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  • 1980-1984  (1.171)
  • 1965-1969  (394)
  • 1982  (1.171)
  • 1968  (394)
  • Life and Medical Sciences  (1.511)
  • Cat
  • Nuclear reactions
Datenquelle
Materialart
Erscheinungszeitraum
  • 1980-1984  (1.171)
  • 1965-1969  (394)
Jahr
Schlagwörter
  • 1
    Digitale Medien
    Digitale Medien
    Modification of spontaneous activity in primary vestibular neurons during development in the cat (1982)
    Springer
    Experimental brain research 45 (1982), S. 265-268 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibular nerve ; Spontaneous activities ; Development ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The spontaneous activity of primary vestibular neurons was studied during postnatal development in the cat. Activities were categorized as regular, intermediate and irregular on the basis of the coefficient of variation. At birth, few regularly firing units were found while the percentage of intermediate and irregular units was high. During development, the percentage of units meeting the criterion of regularity increased steadily with age. At the same time the number of intermediate and irregular units decreased. The average resting rate of all categories of unit showed an increase in firing from birth up to the adult stage, i. e., around the second postnatal month. The mean firing rate of regularly firing units was always higher than the two other categories throughout all the stages of development. These results were compared with similar work performed in the rat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235786
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  • 2
    Digitale Medien
    Digitale Medien
    The depolarization of feline ventral horn group Ia spinal afferent terminations by GABA (1982)
    Springer
    Experimental brain research 46 (1982), S. 215-233 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Spinal Ia terminals ; Primary afferent depolarization ; GABA ; Bicuculline ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The unmyelinated terminal regions of extensor muscle Ia afferent fibres were stimulated electrically near lumbar motoneurones in anaesthetised cats using 300 μs pulses of less than 1 μA passed through the central NaCl barrel of seven barrel micropipettes. Such terminations were identified by anodal blocking factors of less than four and the latency of the antidromic impulse recorded in the appropriate peripheral muscle nerve. Although the effects of microelectrophoretically administered GABA were occasionally complex, the most consistent finding was a reduction in termination threshold followed by an increase. Both this reduction in threshold by GABA, and that produced by tetanic stimulation of low threshold flexor afferents (PAD) were diminished by microelectrophoretic bicuculline methochloride. This GABA antagonist alone elevated the threshold of some terminations but did not reduce the depolarizing action of either potassium or L-glutamate. Furthermore, since reductions in threshold by GABA, but not by either potassium or L-glutamate, were associated with a decrease in PAD, GABA appears to increase terminal membrane conductance. Since neither GABA nor bicuculline methochloride influenced the threshold or afferent depolarization of non-terminal regions of Ia fibres, these results are consistent with the function of GABA as a depolarizing transmitter at gabergic axoaxonic synapses upon the terminals of Ia afferent fibres synapsing with motoneurones.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237180
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  • 3
    Digitale Medien
    Digitale Medien
    The superior colliculus neurons which project to the dorsal and ventral lateral geniculate nuclei in the cat (1982)
    Springer
    Experimental brain research 46 (1982), S. 234-242 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Ventral lateral geniculate nucleus ; Dorsal lateral geniculate nucleus ; Superior colliculus ; Cat ; Efferent projections
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Cells in the cat superior colliculus which project to the ventral and dorsal lateral geniculate nuclei (VLG and DLG) have been labeled by retro-grade transport of horseradish peroxidase (HRP). We studied the depth, area, and morphology of each labeled neuron quantitatively. Our measurements show that the projection neurons to both VLG and DLG vary in laminar position, size, and morphology. Labeled cells projecting to both nuclei were concentrated within the superficial gray layer, but were also scattered through the optic layer and, after DLG injections, in the intermediate gray layer as well. Labeled cells in both groups varied greatly in size, ranging from 49–344 μm2 cross-sectional area (mean 143 μm2) for the VLG group and from 31–398 μm2 (mean 165 μm2) for the DLG group. The labeled cells also varied in morphology after both VLG and DLG injections. The majority had a granule or vertical fusiform morphology. There were fewer with a stellate morphology and almost none with a horizontal morphology. At least three types of superior colliculus cells thus appear to project to the ventral and dorsal lateral geniculate nuclei. These cell types likely give rise to distinct functional channels to these nuclei.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237181
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  • 4
    Digitale Medien
    Digitale Medien
    Spino-olivary projections from the upper cervical spinal cord: An experimental study using autoradiography and horseradish peroxidase (1982)
    Springer
    Experimental brain research 47 (1982), S. 239-251 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Dorsal column nuclei ; Inferior olive ; Upper cervical projections ; Spino-olivary paths ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Spino-olivary projections from segments C1 and C2 were examined in 17 cats using autoradiographic methods and in nine cats using the method of retrograde horseradish peroxidase (HRP) transport. Injections of 3H-leucine at the junction of the C1–C2 segments produced anterograde terminal labelling in two regions of the contralateral inferior olive, one in the rostromedial half of the dorsal accessory olive (DAO), the other in the caudal half of the medial accessory olive (MAO). Projections to the rostromedial DAO were best demonstrated when tracer labelled the ventromedial part of the dorsal horn, while projections to the caudal MAO were strongly labelled by injections in both the lateral and medial parts of the intermediate grey matter. Injections of HRP into the region of the inferior olive led to retrograde marking of cells in both regions of the contralateral spinal cord implicated by autoradiographic studies to have spino-olivary projections. Dense groupings of small rounded or fusiform cells were labelled contralaterally on the medial aspect of the dorsal horn in C1 and C2, while medium-sized multipolar cells were more sparsely distributed throughout intermediate laminae of C1-C5. Olivary projections from dorsal column nuclei were also examined and compared to those of spinoolivary projections. Injections of 3H-leucine into n. gracilis and cuneatus led to terminal labelling in three olivary regions, including the rostral DAO, the caudo-lateral DAO and the caudal MAO. Projections from the DCN to the rostral DAO and the caudal MAO overlapped with regions of projection from upper cervical segments although the territories occupied by DCN and upper cervical projections were not identical. Amino acid injections which were confined to n. cuneatus gave rise to terminal labelling in only the rostromedial DAO.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239383
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  • 5
    Digitale Medien
    Digitale Medien
    Cerebellotectal projections studied in cats with horseradish peroxidase or tritiated amino acids axonal transport (1982)
    Springer
    Experimental brain research 48 (1982), S. 1-12 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cerebellar nuclei ; Superior colliculus ; Horseradish peroxidase ; Autoradiography ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary After injections of horseradish peroxidase (HRP) into various parts of the superior colliculus (SC) in 14 cats, retrogradely labeled neurons were found in parts of all deep cerebellar nuclei. The present study demonstrated that there are three main origins of the cerebellotectal projections in regard to the locations of the cell bodies: (1) the caudal half approximately of the fastigial nucleus (NM) including the subnucleus medialis parvocellularis (SMP), (2) the ventral and lateral parts of the posterior interpositus nucleus (NIP), and (3) the ventral part of the dentate nucleus (NL) including the subnucleus lateralis parvocellularis (SLP). The pathways and terminations of these projections have also been shown autoradiographically. Thus, fibers from NM crossed within the cerebellum and terminated in the intermediate and deep gray layers of the bilateral SC. Fibers from NIP and NL passed within the superior cerebellar peduncle, which crossed in the tegmentum (“decussation” of the peduncle) and ended in the two layers of the contralateral SC. In addition, some cerebellofugal fibers were found to terminate in the nuclei interstitialis of Cajal and Darkschewitsch, as well as in parts of pretectum and thalamus. The tecto-ponto- (and olivo-) cerebellotectal loop (cf. Kawamura 1980) has been established morphologically and it is briefly commented on in correlation with the propagation of the teleceptive (optic and acoustic) impulses.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239567
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  • 6
    Digitale Medien
    Digitale Medien
    The monocular and binocular segment of the cat's visual cortex (1982)
    Springer
    Anatomy and embryology 163 (1982), S. 487-500 
    Details
    ISSN: 1432-0568
    Schlagwort(e): Monocular and binocular visual cortex ; Cat ; Cytoarchitectonic ; Stereology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The aim of this study was to determine the differences between the monocular and binocular segments of the visual cortex in three cats by means of stereological procedures. The cytoarchitectonic images of both segments are described. The thickness of layers in both segments are slightly different. The following results have been obtained. 1. The nerve and glial cell densities are significantly smaller in the monocular segment than in the binocular one. 2. The mean projection area of the neurons is significantly (p〈0.1%) larger in the monocular segment than in the binocular one. Consequently, the mean perikaryon volume in the monocular segment amounts to about one and a half of that in the binocular segment. 3. A two-way variance analysis of neuronal densities and perikaryon sizes shows a significant difference (p〈0.1%) between both segments. 4. The perikaryon volume fraction of the monocular segment is slightly larger than that of the binocular one. 5. The perikaryon size distributions of both segments are different. The shape of the size distributions within the layers vary in both segments. The results are in accordance with the Y-X-W-classification of nerve cells in the visual system. Semi-automatic sterological procedures are capable of detecting distinct functional areas in the brain which are difficult to distinguish visually.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00305561
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  • 7
    Digitale Medien
    Digitale Medien
    Radioautographic study of 3H-GABA uptake in the oculomotor nucleus of the cat (1982)
    Springer
    Experimental brain research 48 (1982), S. 137-143 
    Details
    ISSN: 1432-1106
    Schlagwort(e): GABA uptake ; Radioautography ; Ultrastructure ; Oculomotor nucleus ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The uptake of tritiated γ-aminobutyric acid (3H-GABA) in the oculomotor nucleus of the cat was studied, using light and electron microscopic examination of radioautograms after intracerebral in vivo administration of the amino-acid. A glial uptake by oligodendrocytes was seen together with a neuronal uptake of the tracer in a certain type of axon terminals found in synaptic contact with both dendrites and soma, some of them exhibiting all the ultrastructural features of motoneurons. Previous neurochemical, electrophysiological and immunocytochemical studies indicate that GABA might well be the inhibitory neurotransmitter in the vestibuloocular reflex arc. The present results show that a morphological substrate exists for the presumed postsynaptic GABAergic inhibition of ocular motoneurons, at least in the oculomotor nucleus of the cat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239581
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  • 8
    Digitale Medien
    Digitale Medien
    Thiamine deficiency in the cat leads to severe learning deficits and to widespread neuroanatomical damage (1982)
    Springer
    Experimental brain research 48 (1982), S. 199-208 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Thiamine ; Vitamin B1 ; Cat ; Amnesia ; Brain lesions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Behavioral and neuroanatomical consequences of a thiamine-deficient diet, combined with the application of a thiamine-antagonist (pyrithiamine) were investigated in the cat. Eight cats (the experimental group) were subjected to a vitamine-B1-poor diet until they developed neurological symptoms (epileptic attacks, ataxia, gait disturbances), while 24 cats were fed normally and served as control group. Immediately following the appearance of neurological signs, a high dose of thiamine was given to the cats of the experimental group; they were then allowed to recover for ten days. Thereafter the performance in learning an alternation task in a T-maze was tested and compared with that of the control group. Behaviorally, the cats of the experimental group manifested drastically retarded acquisition rates in the learning task compared to the cats of the control group. Neuroanatomically, damage was found in the brains of each of the cats in the experimental group; this damage consisted mainly of enlarged ventricles, hemorrhages, neuronal loss and gliosis. Those regions most consistently affected were the periaqueductal gray, the inferior colliculi and the mamillary nuclei. The thalamic mediodorsal nucleus was affected to a minor degree in three cats only. Four cats manifested damage in the hippocampal formation. No damage was found in the cerebellum. Most of the damaged neuroanatomical loci resemble those found in patients with a Wernicke-Korsakoff syndrome.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237215
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  • 9
    Digitale Medien
    Digitale Medien
    A quantitative study of the classification and stability of ocular dominance in the cat's visual cortex (1982)
    Springer
    Experimental brain research 48 (1982), S. 401-408 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Striate cortex ; Ocular dominance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We recorded from single cells in the cat's visual cortex to quantitatively evaluate (1) the reliability of subjective assessments of ocular dominance (101 cells) and (2) the stability of ocular dominance over time (25 cells). We found that the correlation between subjective and objective measures of this variable was poorer than expected, and was worst for cells with low overall response strengths. This result appears to reflect variability in the subjective assessment procedure. For the second part of the study, we recorded from single cortical cells of 5-week-old kittens, and made repeated objective measurements of ocular dominance over time. Twenty-four of the twenty-five cells examined were quite stable in ocular dominance for periods so long as 8 h. One unit was encountered which showed substantial progressive shifts in ocular dominance over time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238616
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  • 10
    Digitale Medien
    Digitale Medien
    Retinotopic organization of extra-retinal saccade-related input to the visual cortex in the cat (1982)
    Springer
    Experimental brain research 46 (1982), S. 368-376 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Saccade-related activity ; Retinotopic organization ; Visual cortex ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Single unit activity of 842 cells has been recorded in cat visual cortex and analyzed with respect to vestibular induced, and spontaneous saccadic eye movements performed in the dark. This study has been done in awake, chronically implanted cats, subsequently placed in “acute” conditions to achieve the precise retinotopic mapping of the cortical areas previously investigated. In areas 17 and 18, respectively, 27% and 24% of the cells tested were influenced by horizontal saccadic eye movements in the dark (E. M. cells). In the Clare-Bishop area, the proportion of E. M. cells was 12%, while only 2% of such cells were found in areas 19 and 21. The distribution of E.M. cells in areas 17 and 18 with respect to retinotopy showed that E.M. cells were more numerous in the cortical zones devoted to the representation of the area centralis (38% in area 17, 27% in area 18) than in the zones subserving the periphery of the visual field (17% and 12%, respectively). Two of the characteristics of E. M. cell activations appear dependant on the retinotopic organization. First, a larger number of E.M. cells presenting an asymmetry in their responses to horizontal saccadic eye movements in opposite directions (directional E.M. cells) were encountered in the cortical representation of the peripheral visual field. 53% of E. M. cells recorded in area 17 and 71% in area 18 were directional in the cortex corresponding to the peripheral visual field. This percentage was of 23% and 25% respectively in the cortex devoted to area centralis. Second, E.M. cells were found to have a latency from the onset of the saccade systematically larger than 100 ms (i.e, they discharged at, or after the end of the eye movement) if they were located in the cortical representation of the area centralis, while E.M. cells related to the peripheral visual field displayed a wider range of latencies (0–240 ms). Results obtained in Clare Bishop area, although limited to the representation of the peripheral visual field, were quantitatively and qualitatively similar to those observed in the homologous retinotopic zones of areas 17 and 18. It is concluded that an extra-retinal input related to oculomotor activity is sent to the cat visual cortex and is organized, at least in areas 17 and 18, with respect to the retinotopic representation of the visual field. These data support the hypothesis of a functional duality between central and peripheral vision and are discussed in the context of visual-oculomotor integration.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238631
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  • 11
    Digitale Medien
    Digitale Medien
    Interlimb coordination in cat locomotion investigated with perturbation (1982)
    Springer
    Experimental brain research 46 (1982), S. 438-447 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Deiters' neurons ; Locomotion ; Perturbation ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The effects of mechanical stimulation (tap) on single unit activity of Deiter's neurons were analysed in walking cats decerebrated at the premammillary level. Deiters' neurons projecting to the ipsilateral cervical, but not to the lumbosacral, spinal cord (C-Deiters' neurons) were identified by antidromic activation, cerebellar stimulation, and localization of the neurons. During each unperturbed cycle of quadrupedal locomotion, most C-Deiters' neurons showed two frequency modulation peaks in their impulse discharges: one (A peak) in the late swing (E1) or the early stance (E2) phase, the other (B peak) in the late stance (E3) or the early swing (F) phase, of the ipsilateral forelimb. The A peak started to rise shortly before the ipsilateral forelimb was placed. When mechanical perturbation was applied during locomotion to the paw dorsum of the left forelimb (LF) in its stance phase, the ongoing LF stance phase shortened and the simultaneous swing phase of the right forelimb (RF) shortened. Accordingly, in the RF, extensor activity in the swing phase to place down the limb occurred earlier than in unperturbed step cycles. The same LF tap induced a marked enhancement of impulse discharges in C-Deiters' neurons on the right side (with a magnitude of 20–100 imp/s, and the shortest latency of 25 ms). This enhancement was more pronounced than that induced when the perturbation was applied to the LF during its swing phase. The latency manifested a close time relation to the RF extensor activity supporting the postulate that the increased C-Deiters' activity in the RF swing phase contributes to the earlier onset of RF extensor activity which plays an important role in maintaining alternating footfalls after perturbation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238638
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  • 12
    Digitale Medien
    Digitale Medien
    Horizontal eye position-related activity in neck muscles of the alert cat (1982)
    Springer
    Experimental brain research 46 (1982), S. 448-453 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Eye-head coordination ; Vestibular nystagmus ; Visuo-motor system ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The activity of neck muscles was recorded in the alert, head-fixed cat together with the horizontal and vertical components of eye movements. Electromyographic activity of obliquus capitis cranialis and caudalis, and longissimus capitis, is closely related to horizontal eye position in the orbit both during spontaneous eye movements and vestibular nystagmus. The activity of splenius also shows this relationship but the coupling is less tight, probably because of the postural function of this muscle.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238639
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  • 13
    Digitale Medien
    Digitale Medien
    Inhibition of periaqueductal gray neurons by the arcuate nucleus: Partial mediation by an endorphin pathway (1982)
    Springer
    Experimental brain research 46 (1982), S. 462-466 
    Details
    ISSN: 1432-1106
    Schlagwort(e): β-Endorphin ; Periaqueductal gray ; Cat ; Arcuate nucleus ; Naloxone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electrical activation of the ipsilateral arcuate region of the hypothalamus produced an inhibitory influence upon three separate subpopulations of cells encountered in the ventrolateral PAG. Quiescent PAG cells were classified by their response pattern to sural nerve stimulation: Type A cells displayed only a short latency discharge; whereas, Type B cells exhibited a triphasic response pattern. Arcuate nucleus stimulation dramatically reduced the evoked discharge of both A and B cell types. Type C cells represented spontaneously active PAG neurons which were less affected by arcuate nucleus activation. Systemic naloxone (5 mg/kg) reduced the degree of inhibition of only Type B neurons. Naloxone was ineffective in attenuating arcuate inhibition of Type A and C neurons. Type B neurons may represent a class of cells which are more involved in nociceptive systems and therefore are susceptible to modulation by endogenous opiate peptides.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238642
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  • 14
    Digitale Medien
    Digitale Medien
    Single neuron activity related to natural vestibular stimulation in the cat's visual cortex (1982)
    Springer
    Experimental brain research 45 (1982), S. 451-455 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibular input ; Visual cortex ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary This study examines the possibility of a vestibular input to the visual cortex using chronically implanted cats subjected to horizontal sinusoïdal rotation in the dark. In areas 17 and 18 the activity of respectively 14% and 11% of units was modified by vestibular stimulation. Both non-specific and specific influences were observed. Specific influences (42% in area 17 and 33% in area 18) were similar to the types of responses recorded in the vestibular nuclei, and were encountered more frequently within the cortex subserving the peripheral visual field. Our results could provide a neurophysiological basis for some psychophysiological observations concerning visuo-vestibular interactions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01208606
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  • 15
    Digitale Medien
    Digitale Medien
    Connections of the hippocampal formation, mamillary bodies, anterior thalamus and cingulate cortex (1982)
    Springer
    Experimental brain research 47 (1982), S. 79-94 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Horseradish peroxidase ; Cat ; Limbic system ; Hippocampal formation ; Mamillary bodies
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The afferent projections to, and the interconnections between, four structures of the socalled limbic system were investigated in the cat. The retrograde horseradish peroxidase (HRP) technique was used to trace the origins of fibers projecting to each of these four loci. Particular emphasis was laid on tracing cortical afferents of these regions. Four injections were performed in the dorsal and two in the ventral subicular regions; six were centered within the mamillary nuclei, four within the anterior thalamic nuclei, and three within the cingulate gyrus. For each region, a number of projections were found which had apparently not been described before, at least not for the cat: For injections into the subicular regions, a hitherto unknown number of cortical afferents was detected, including labeled cells in the prefrontal and premotor fields and from large areas within the posterior parietal, temporal and occipital cortex (i.e., sensory and sensory integration cortex); numerous neurons were labeled in the anterior nuclear group of the thalamus. Injections of HRP into the mamillary nuclei revealed, aside from a strong projection from the subicular regions, frontocortical and cingulate projections to the mamillary nuclei; the mamillary nuclei also received subcortical projections from the septum, the diagonal band of Broca and from the periaqueductal gray. Following injections into the anterior thalamic nuclei, labeled cells were found in the prefrontal cortex, and to a lesser extent in lateral parts of the cortical hemisphere; subcortically, the mamillary nuclei received connections from hypothalamic areas, the periaqueductal gray, the diagonal band of Broca and the claustrum. Cingulate injections labeled cells in temporal and parietal cortical areas, in the subicular region, and also in the periaqueductal gray. Our findings reveal that each of the four injected areas receives a large number of afferents from divergent regions of the brain; of these, a considerable number is shared by each of the four injection loci. Furthermore, the present results reveal that the subiculum, the mamillary bodies, and the anterior thalamus are more strongly interconnected than previously assumed.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235889
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  • 16
    Digitale Medien
    Digitale Medien
    Central core control of developmental plasticity in the kitten visual cortex: I. Diencephalic lesions (1982)
    Springer
    Experimental brain research 47 (1982), S. 209-222 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Developmental plasticity ; Visual cortex ; Attention ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary In five, dark-reared, 4-week-old kittens the posterior two thirds of the corpus callosum were split, and a lesion comprising the intralaminar nuclei was made of the left medial thalamic complex. In addition, the right eye was closed by suture. Postoperatively, the kittens showed abnormal orienting responses, neglecting visual stimuli presented in the hemifield contralateral to the side of the lesion. Sudden changes in light, sound, or somatosensory stimulation elicited orienting responses that all tended toward the side of the lesion. These massive symptoms faded within a few weeks but the kittens continued to neglect visual stimuli in the hemifield contralateral to the lesion when a second stimulus was presented simultaneously in the other hemifield. Electrophysiologic analysis of the visual cortex, performed after the end of the critical period, revealed marked interhemispheric differences. In the visual cortex of the normal hemisphere most neurons were monocular and responded exclusively to stimulation of the open eye, but otherwise had normal receptive field properties. In the visual cortex of the hemisphere containing the thalamic lesion, the majority of the neurons remained binocular. In addition, the selectivity for stimulus orientation and the vigor of responses to optimally aligned stimuli were subnormal on this side. Thus, the same retinal signals, which in the control hemisphere suppressed the pathways from the deprived eye and supported the development of normal receptive fields, failed to do either in the hemisphere containing the thalamic lesion. Apparently, experience-dependent changes in the visual cortex require both retinal stimulation and the functioning of diencephalic structures which modulate cortical excitability and control selective attention.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239380
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  • 17
    Digitale Medien
    Digitale Medien
    Supraspinal facilitation of cutaneous polysynaptic EPSPs in cat medial gastrocnemius motoneurons (1982)
    Springer
    Experimental brain research 45 (1982), S. 133-143 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cutaneous reflexes ; Supraspinal control ; Motoneurons ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary We examined the characteristics of postsynaptic potentials (PSPs) produced in antidromically-identified medial gastrocnemius (MG) α-motoneurons by electrical stimulation of low threshold (〈 3×T) distal limb cutaneous afferents in the sural (SUR) nerve in adult cats anesthetized with α-chloralose, together with the effects on SUR PSPs of supraspinal conditioning stimulation of the contralateral red nucleus (RN) and pyramidal tract (PT). In the majority of MG motoneurons, SUR afferents with electrical thresholds 〈 1.5×T produced early excitatory synaptic potentials (EPSPs) with minimum central latency of about 2.0 ms, suggesting activation of a trisynaptic segmental pathway with two interposed interneurons. Such early EPSPs were often detectable with stimuli 〈 1.2×T, as determined by recording the compound action potential in the sciatic nerve and from the first appearance of the N1 wave of the cord dorsum potential. Inhibitory synaptic potentials (IPSPs) were regularly produced by SUR volleys of only slightly greater strength (often as low as 1.3×T) and these had minimum central latencies of about 3.0 ms (about 1.0 ms longer than the earliest EPSPs), suggesting a three interneuron central pathway. Repetitive stimulation of RN and PT regularly produced facilitation of both EPSP and IPSP components in the SUR response, suggesting that these supraspinal systems directly or indirectly excite some of the same interneurons that convey the SUR effects to MG motoneurons. When using very low strength SUR stimuli, PT conditioning produced relatively pure facilitation of the SUR EPSPs but with larger SUR volleys, PT clearly facilitated both EPSPs and IPSPs. RN conditioning produced more parallel facilitation of SUR EPSPs and IPSPs. Supraspinal control of the polysynaptic pathway producing SUR EPSPs is of particular interest because of earlier evidence that this pathway is differentially distributed to motoneurons of fast twitch versus slow twitch MG motor units.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235772
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  • 18
    Digitale Medien
    Digitale Medien
    The control of rapid limb movement in the cat (1982)
    Springer
    Experimental brain research 45 (1982), S. 115-125 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Voluntary movement ; Cat ; Triphasic ; EMG ; Antagonist
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Electromyographic (EMG) activity associated with rapid voluntary limb movements exhibits a characteristic “three burst pattern”. The first burst is in the agonist muscle (AG1), the second is in the antagonist (ANT) and the third is again in the agonist (AG2). The present study was undertaken to determine whether ANT and AG2 reflect preprogrammed commands or responses to stretch consequent upon limb displacement. To answer this question EMG activity of agonist and antagonist muscles was examined in cats performing a tracking task. To dissociate centrally programmed muscular events from their intended mechanical consequences, isometric and anisometric conditions were presented in either a predictable or unpredictable sequence. A torque motor was used to control limb trajectory and to impose passive angular displacements. Whereas AG1 was present under both isometric and anisometric conditions, ANT and AG2 required limb displacement and were time locked to movement parameters. ANT occurred within 15 ms following the onset of acceleration. Its magnitude varied linearly with this parameter and inversely with AG1. Passive displacements stretching the antagonist elicited responses with similar latencies and greatest magnitude for a given acceleration. AG2 was only present in underdamped movements with terminal oscillations and typically occurred when the position reached its peak and the velocity recrossed zero. Its magnitude was a function of both limb deceleration and of intended force. The data indicate that both ANT and AG2 represent responses to muscles stretch whose amplitudes are modulated by descending commands. Reciprocal mechanisms operating at a spinal level could account for the reduction of the antagonist response as a function of intended force. The increased sensitivity of late stretch responses in the agonist with higher intended forces is compatible with motoneuron facilitation by tonic descending commands. It is proposed that the stretch evoked responses function to dampen terminal oscillations which ensue from rapid displacement of the mass of the limb against elastic forces of muscle and soft tissue.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235770
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  • 19
    Digitale Medien
    Digitale Medien
    Canal-neck interaction in vestibular nuclear neurons of the cat (1982)
    Springer
    Experimental brain research 46 (1982), S. 269-280 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Vestibular nuclear neurons ; Canal-neck interaction ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The convergence and interaction of horizontal semicircular canal and neck proprioceptive inputs were studied in neurons of the caudal two thirds of the vestibular nuclear complex. Extracellular neuron activity was recorded under muscle relaxation and slight anesthesia in chronically prepared cats. The following stimulations were applied: horizontal rotations of (a) the whole body (labyrinth stimulation), (b) the trunk vs. the stationary head (neck stimulation), and (c) the head vs. the stationary trunk (combined labyrinth and neck stimulation). Of 152 neurons investigated, 83 (55%) showed convergence of the two inputs. In about half of these neurons, the neck input was very weak and hardly affected the labyrinthine response during head rotation. Judged from the response pattern, several of these neurons presumably were related to vestibulo-oculomotor function (i.e., vestibular nystagmus). In the other half (i.e., 27% of all neurons), sensitivity of the two inputs was similar. Both labyrinthine and neck responses contained a dynamic (“velocity”) component; neck responses of more than half of these neurons had, in addition, a static (“position”) component. The dynamic components were either “antagonistic” or “synergistic” as to their convergence during head rotation. When applying this combined stimulation, the dynamic components summed linearly, yielding subtraction in case of antagonistic convergence and addition in case of synergistic convergence. In contrast, the static components of the neck responses remained largely unchanged during head rotation. However, the static head-to-trunk deflection determined the tonic discharge level in such neurons and thus facilitated or disfacilitated the dynamic responses to superimposed labyrinth stimulation. We suggest that the two patterns of labyrinthine-neck interaction observed in vestibular nuclear neurons, i.e., subtraction and addition, may be involved in the postural control of the trunk and head, respectively. In contrast, interference of the neck input with vestibule-oculomotor function appears to be almost negligible in the intact cat.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237185
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  • 20
    Digitale Medien
    Digitale Medien
    An “oblique effect” in the visual evoked potential of the cat (1982)
    Springer
    Experimental brain research 46 (1982), S. 151-154 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Oblique effect ; Visual evoked potentials ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary An oblique effect was observed in the amplitude of the VEP recorded from area 17 of the cat. The ratio of the responses to oblique gratings compared with responses to horizontal and vertical gratings averaged 0.77. Orientation dependence was strongest at low spatial frequencies, unlike the effect found in primates.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238110
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  • 21
    Digitale Medien
    Digitale Medien
    Bilateral projections from the visual cortex to the striatum in the cat (1982)
    Springer
    Experimental brain research 47 (1982), S. 28-32 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cortico-striatal projections ; Cat ; Visual cortex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Direct projections from visual areas 17, 18, 19, and lateral suprasylvian visual area (LS) to the striatum were searched for in 12 adult cats using the autoradiographic technique to detect neuronal pathways. Striatal labels were found only after injections in areas 19 and LS. Projections homolateral to the injection sites were observed from both areas to the head and body of the caudate nucleus and to the putamen. Contralateral projections were found from both areas 19 and LS: however, area 19 did not project to the contralateral putamen. The extent of contralateral projections was smaller and they were confined within the same regions as the homolateral ones. Silver grains were often arranged in cluster-like patches, which were more evident ipsilaterally, in the head of the caudate nucleus and after injections in area LS. The present data support the view of a not strictly topographical segregation of striatal projections from the cat visual cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235882
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  • 22
    Digitale Medien
    Digitale Medien
    Thalamocortical neurons projecting to the areas surrounding the anterior and middle suprasylvian sulci in the cat (1982)
    Springer
    Experimental brain research 45 (1982), S. 59-70 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Thalamocortical connection ; Cat ; Suprasylvian sulcus area ; Horseradish peroxidase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The thalamic projections to the cortical area surrounding the anterior (ASs) and middle (MSs) suprasylvian sulci in the cat were studied using horseradish peroxidase histochemistry. The medial MSs area (medial wall of the MSs) receives thalamic afferents from the pulvinar-lateralis posterior (Pul-LP) complex, posterior nucleus (Pn) and medial interlaminar nucleus (MIN) and C laminae of the dorsal lateral geniculate nucleus (GLd). Groups of labeled cells in the Pul-LP complex are arranged to form four different neuronal bands oriented dorsoventrally. The four neuronal bands are located, laterally to medially, in the lateral and medial parts of Pul and in the lateral and central parts of LP. The ventral ends of the first (in the lateral Pul) and the third (in the lateral LP) bands extend to MIN and Pn, respectively. The locations of the four bands in the Pul-LP complex appear to correspond to the terminal fields of afferents from four different regions (retina, pretectum, visual cortex and superior colliculus) related to visual function. The anterior part of the lateral MSs area (lateral wall of the MSs) receives thalamic fibers from the lateral and intermediate divisions of the posterior nuclear group (POl and POi), while its posterior part receives fibers from the dorsal and medial parts of LP and POi. Both walls of the ASs receive fibers from the ventrolateral part of LP as well as from the anterior part of POl and the POl-POm border. In addition, the ASs-MSs area receives fibers from the central lateral nucleus (CL) It is of interest to correlate the locations of cells projecting to the ASs-MSs area with the pathways terminating in thalamic regions. It is clear that, from the hodological point of view, the ASs-MSs area is functionally segregated, which is in agreement with previous studies we have made of corticocortical connections.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235763
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  • 23
    Digitale Medien
    Digitale Medien
    Central core control of developmental plasticity in the kitten visual cortex: II. Electrical activation of mesencephalic and diencephalic projections (1982)
    Springer
    Experimental brain research 47 (1982), S. 223-233 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Development ; Plasticity ; Central core ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Fifteen dark-reared, 4- to 5-week-old kittens were stimulated monocularly with patterned light while they were anesthetized and paralyzed. Six of these kittens were exposed to the light stimuli only, in four kittens the light stimuli were paired with electric stimulation of the mesencephalic reticular formation and in five kittens with electric activation of the medial thalamic nuclei. Throughout the conditioning period, the ocular dominance of neurons in the visual cortex was determined from evoked potentials that were elicited either with electric stimulation of the optic nerves or with phase reversing gratings of variable spatial frequencies. In two kittens, ocular dominance changes were assessed after the end of the conditioning period by analyzing single unit receptive fields. Monocular stimulation with patterned light induced a marked shift of ocular dominance toward the stimulated eye, when the light stimulus was paired with electric activation of either the mesencephalic reticular formation or of the medial thalamus. Moreover, a substantial fraction of cells acquired mature receptive fields. No such changes occurred with light or electric stimulation alone. It is concluded that central core projections which modulate cortical excitability gate experience-dependent modifications of connections in the kitten visual cortex.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239381
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  • 24
    Digitale Medien
    Digitale Medien
    Contralateral corticofugal projections from the lateral, suprasylvian and ectosylvian gyri in the cat (1982)
    Springer
    Experimental brain research 47 (1982), S. 234-238 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Connections ; Auto-radiography ; Superior colliculus ; Intralaminar nuclei ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Contralateral corticofugal projections were investigated following multiple injections of a mixture of tritiated leucine and proline into the lateral, postlateral, suprasylvian and ectosylvian gyri of adult cats. Transported label was found in several Contralateral subcortical regions. These included the claustrum, caudate-putamen, thalamic intralaminar nuclei, pretectum, and the superior and inferior colliculi. These results show that the crossed corticofugal projections are common in the cat and are more extensive than has been previously reported.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00239382
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  • 25
    Digitale Medien
    Digitale Medien
    Distribution of physiological types of motor units in the cat peroneus tertius muscle (1982)
    Springer
    Experimental brain research 48 (1982), S. 177-184 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Motor unit types ; Twitch and tetanic tensions ; Potentiation ; Peroneus tertius muscle ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Motor units of the cat peroneus tertius muscle were systematically analyzed using the criteria established by Burke et al. (1973). On the basis of their speed of contraction and resistance to fatigue, 121 (97%) of 125 motor units examined in ten adult cats could be classified as belonging to one of four types: fast-fatiguable (FF), fast-resistant (FR), fast-intermediate (FI), and slow-resistant (S). Peroneus tertius was found to contain 30% FF motor units, 9% FI units, 39% FR units, and 22% S units. Contraction times of fast motor units (FF, FR, and FI) ranged from 15 to 27 ms and those of S units from 26 to 42 ms. The mean tetanic tensions were 37 g for FF units, 29 g for FI units, 7.5 g for FR units, and 1.1 g for S units. Fast motor units displayed considerable post-tetanic potentiation of twitch tension. Under similar conditions of stimulation, FF units appeared able to potentiate more and faster than FR units.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237213
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  • 26
    Digitale Medien
    Digitale Medien
    A high probability of an orientation shift between layers 4 and 5 in central parts of the cat striate cortex (1982)
    Springer
    Experimental brain research 48 (1982), S. 245-255 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Visual cortex ; Cat ; Orientation columns ; Perpendicular penetrations ; Orientation shift
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary On the postlateral gyrus of the cat striate cortex the cells' preferred orientation was measured as a function of cortical depth in penetrations as parallel as possible to the radial fibre bundles. According to the penetration angle and in agreement with the current model of orientation columns, there was a low orientation drift in layers 2–4. At the transition between layers 4 and 5 an orientation shift of 45–90 deg was found in most penetrations. The orientation differences between adjacent recording sites in lower layers was normally low too, but clearly higher than in upper layers. The results are discussed in terms of more independent orientation mechanisms in upper and lower layers.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00237220
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  • 27
    Digitale Medien
    Digitale Medien
    Velocity sensitivity mechanisms in cat visual cortex (1982)
    Springer
    Experimental brain research 45 (1982), S. 285-294 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Velocity sensitivity ; Upper cut-off velocity ; Temporal summation ; Cat ; Visual cortex
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary To understand why some cells in the visual cortex respond to high stimulus velocities while others fail to do so, a sample of 71 of such cells were examined for their responses to stationary presented stimuli as well as to moving edges or slits of different widths. When presented with stationary stimuli it was found that cells which respond best to slowly moving stimuli generally have tonic discharges, long time to peak latencies and often long minimal durations of stimulation. In contrast, cells which respond preferentially to fast stimuli have phasic discharges, short latencies and short critical durations of stimulation when presented with stationary flashed slits. In the latter type of cells the responses to very fast stimulus movement were abolished selectively when contrast and width of the stimulus were not optimal. A few cells exhitited a velocity-response (VR) curve with a central dip indicating good responsiveness to either slow or fast movement but little to medium velocities. These cells responded both phasically and tonically to stationary slits and the latency of the tonic and phasic responses corresponded well to the latency of the responses at low and high velocities, respectively. It is suggested that the ability of phasic cells to respond to high velocities is linked to their limited need for temporal summation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00235789
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  • 28
    Digitale Medien
    Digitale Medien
    Descending projections to the inferior olive from the mesencephalon and superior colliculus in the cat (1982)
    Springer
    Experimental brain research 45 (1982), S. 333-348 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Inferior olive afferents ; Mesencephalon ; Superior colliculus ; Autoradiography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Descending projections from the mesencephalon and superior colliculus to the inferior olive were analyzed by an autoradiographic tracing method. Injections of tritium-labelled leucine were placed in regions which had previously been identified as sources of afferents to the olive. These were located adjacent to the central gray and extended from the rostral red nucleus to the posterior thalamus. Additional injections were made in the superior colliculus. Other injections were placed in the basal ganglia and thalamus. Injections restricted to one side of the central mesencephalon resulted in predominantly ipsilateral labelling of the olive. After injections in the caudo-medial parafascicular and subparafascicular nuclei and rostral nucleus of Darkschewitsch, deposits of grains were observed in the rostral pole of the medial accessory olive and adjacent ventral lamella of the principal olive. The medial accessory olive contained grains into its middle third. More caudal injections which involved the interstitial nucleus of Cajal as well as the nucleus of Darkschewitsch and rostral red nucleus resulted in the dense labelling of the entire principal olive (except the dorsal cap), the entire medial acessory olive (except subnucleus β and the caudo-medial pole) and the caudo-dorsal accessory olive. Injections centered in the caudal magnocellular red nucleus and extending into the rostral parvocellular division labelled the dorsal lamella of the principal olive almost exclusively. When only the caudal part of the red nucleus was involved in the injection, the olive was entirely clear of grains. Minor contralateral distributions were observed in the dorsomedial cell column, the medial tip of the dorsal lamella and in the caudal medial accessory olive. The deep layers of the superior colliculus were found to project strongly to the contralateral medial accessory olive immediately beside subnucleus β and weakly to the same area ipsilaterally. Four pathways were identified as contributing fibers to the olivary projections. These were the medial longitudinal fasciculus, the medial tegmental tract, the central tegmental tract and tectospinal or tectobulbar fibers. The rubrospinal tract did not contribute projections to the olive. Injections in the caudate nucleus, entopeduncular nucleus and ventral anterior and ventral lateral thalamic nuclei, did not result in any labeling in the olive.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01208593
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  • 29
    Digitale Medien
    Digitale Medien
    Dorsolateral spinal afferents to some medullary sensory nuclei (1982)
    Springer
    Experimental brain research 46 (1982), S. 12-23 
    Details
    ISSN: 1432-1106
    Schlagwort(e): Cat ; Medullary nuclei ; Dorsolateral spinal afferents ; Orthograde degeneration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The course and termination of afferents in the spinal dorsolateral fascicle to some medullary sensory nuclei were studied by tracing degeneration following lesions of spinal white matter. The main conclusions depend on successive degeneration experiments; other points were studied with single-stage lesions. The dorsal column nuclei were particu-larly studied; terminations in these nuclei following dorsolateral lesions followed a clear-cut pattern, with fibres arising from segments below T 6 terminating in the gracile nucleus and those with more rostral origin solely in the cuneate nucleus. In both nuclei, the major terminations were in their rostral third with most fibres traversing deep caudal regions where some termination also occurred. Some fibres ended contralaterally. These restricted regions of termination contrasted with the wide-spread terminations seen after lesions of the dorsal column. A region at the cuneate rostral pole, adjacent to but clearly separable from nucleus z, receives a dense projection from both caudal and rostral spinal levels, the former fibres terminating in the dorsal part of the region, the latter extending more ventrally. We treat this as a separate subnucleus. The afferents to the dorsal column nuclei (together with those terminating in the other nuclei studied) were confined to the extreme dorsolateral white matter. Our observations confirm the established view that only afferents arising from caudal segments (below at least T 4–5) terminate in nucleus z, and that afferents terminating in group x arise from all levels (at least between C 5 and L 5): also that neither receives any afferents through the dorsal columns. Dorsolateral fibres arising from segments above at least T 6 terminate in a clear-cut area at the lateral border of the external cuneate nucleus. Heavy terminal degeneration was also seen in the lateral cervical nucleus of afferents arising from both above and below T4–5
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00238093
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  • 30
    Digitale Medien
    Digitale Medien
    Augmentation of vagal reflex bradycardia by central α1adrenoceptors in the cat (1982)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 321 (1982), S. 44-47 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Vagal reflex bradycardia ; Carotid sinus nerve stimulation ; Depressor nerve stimulation ; Clonidine ; Yohlmbine ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Vagal reflex bradycardia was induced in anaesthetized cats with high level spinal axotomy by electrical stimulation of either the carotid sinus nerves or a depressor nerve. In both preparations reflex bradycardia increased with the rate of stimulation. Injection of 1 μg/kg clonidine into a lateral cerebral ventricle augmented reflex bradycardia in response to carotid sinus nerve stimulation while the same dose of clonidine was ineffective when given intravenously. The antagonistic effect of intracerebroventricular yohimbine (50 μg/kg) indicated that the effect of clonidine was due to its α1agonistic action. In contrast to carotid nerve stimulation the reflex bradycardia in response to depressor nerve stimulation was affected neither by intracerebroventricular injection of clonidine (2 μg/kg) nor by yohimbine (100 μg/kg). It is concluded that in the cat, the function of the central parts of the baroreceptor reflex which originate from the carotid sinus area is augmented by stimulation of α1adrenoceptors while the function of those parts originating from the aortic area is not.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00586347
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  • 31
    Digitale Medien
    Digitale Medien
    Release of endogenous histamine in the hypothalamus of anaesthetized cats and conscious, freely moving rabbits (1982)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 321 (1982), S. 282-286 
    Details
    ISSN: 1432-1912
    Schlagwort(e): Release of endogenous histamine ; Hypothalamus ; Cat ; Freely moving rabbit ; Electrical stimulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The hypothalamus of anaesthetized cats and conscious, freely moving rabbits was superfused with CSF through double-walled, push-pull cannulae and the release of endogenous histamine was determined in the superfusates by a radioenzymatic assay. In the posterior hypothalamic area of the anaesthetized cat, the rate of release of endogenous histamine varied rhythmically; phases of high rate of release appeared at 60 min cycles. The release of histamine was increased by electrical stimulation of the superfused area, as well as by hypothalamic superfusion with potassium-rich CSF. In the conscious rabbit, the anterior hypothalamic area and the posterior hypothalamic nucleus were superfused simultaneously. In both regions, the resting release of histamine varied rhythmically at approximately 70 min cycles. Phases of high or low-rate of release in the anterior hypothalamic area coincided with the corresponding phases in the posterior hypothalamic nucleus. The rhythmic release of endogenous histamine in the hypothalamus, as well as the ability of depolarizing stimuli to enhance the release of the amine support the idea that histamine acts as a neurotransmitter in the central nervous system.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00498514
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  • 32
    Digitale Medien
    Digitale Medien
    Electrophysiological mapping of sympathetic nuclei in the L2 and L3 segments of the spinal cord (1982)
    Springer
    Pflügers Archiv 394 (1982), S. 156-160 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Spinal sympathetic nucleus ; Antidromic field potential analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The spinal sympathetic preganglionic nuclei were mapped using antidromic field potential analysis during electrical stimulation of L2 and L3 white rami. The spinal sympathetic nuclei were localized respectively in L2 and L3 segments of the lumbar cord as a narrow strip along craniocaudal axis of the spinal cord. The caudal and of each preganglionic sympathetic nucleus was localized caudally to the corresponding dorsal root entry (DRE). The cranial end of the nucleus in different experiments was localized at different levels along the corresponding DRE or cranial to the corresponding DRE. We suggest that neurones which send axons to a single white ramus form an anatomically separate sympathetic preganglionic nucleus in the lumbar spinal cord within one segment.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00582918
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  • 33
    Digitale Medien
    Digitale Medien
    Responses of cat dorsal spino-cerebellar tract neurons to sinusoidal stretching of the gastrocnemius muscle (1982)
    Springer
    Pflügers Archiv 395 (1982), S. 99-107 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Dorsal spino-cerebellar tract ; Signal transmission from Ia afferents ; Sinusoidal muscle stretch ; Quantitative analysis ; Cat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A defined class of cells within the nucleus dorsalis (Clarke's column) receives excitatory input from Ia afferents of mainly one muscle. Action potentials were recorded from axons of these cells (DSCT neurons) which are excited by Ia afferents of the gastrocnemius muscles. We investigated the response to sinusoidal muscle stretch over a wide range of amplitudes (10 μm–4 mm) and frequencies (0.1–130 Hz) in the deefferented preparation. The dynamic stretch was superimposed on a moderate static muscle stretch to ensure that the muscle was not slack during the phase of release. The response up to 10 Hz was displayed as PST histograms (cycle histograms) and a sinewave of stretch frequency was fitted to the PST histograms to define amplitude and phase of a response sinewave. At a constant frequency of about 3Hz, the relation between stretch amplitude and response amplitude could well be described by decelerating intensity functions: the hyperbolic or tanh log function and a modified power function (exponent 0.48±0.12). The phase lead of the response sinewave increased with increasing stretch amplitudes of up to 0.5 mm and then decreased. At constant stretch amplitudes of 0.5–2.0 mm the frequency response was investigated. In relation to stretch frequencies between 0.1 and 1 Hz an increase in the response amplitude of 4.4dB was observed and an increase for 13dB/decade between 3 and 10 Hz. At 0.1 Hz the phase of the response sinewave was 48° in advance and increased to a maximum lead of 89° at 6–8Hz. Above 10Hz the positions of the responding action potentials with respect to the stretch cycle were used to define a phase, which was in advance up to 60 Hz but decreased and changed to a phase lag at higher frequencies. If in PST histograms no periods of silence occurred during the phase of stretch release, the mean discharge rate was found to be independent of the sinusoidal stretching. If the pauses were present the mean rate increased with increasing stretch frequencies or amplitudes.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00584721
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  • 34
    Digitale Medien
    Digitale Medien
    Arterial chemoreceptor inhibition by a single inspirate containing carbon monoxide is accounted for by raised arterial $$P_{ O_2 }$$ (1982)
    Springer
    Pflügers Archiv 393 (1982), S. 313-317 
    Details
    ISSN: 1432-2013
    Schlagwort(e): Cat ; Carbon monoxide ; Chemoreceptor mechanism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Carbon monoxide (CO) slugs (10–100 ml) injected into the inspired air of 6 hypoxic, anaesthetized cats reduced carotid body chemoreceptor discharge. The inhibition was invariably associated with a sharprise in $$P_{a, O_2 }$$ which was continuously recorded by a fast responding intravascular electrode. This suggests that CO in solution in the blood leaving the lungs displaces O2 from blood after it has left the exchange region and that the displaced O2 raises the $$P_{a, O_2 }$$ and inhibits chemoreceptor discharge. Our results provide no support for the idea that a haemoglobin-like pigment is involved in the mechanism of arterial chemoreceptor excitation.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00581416
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  • 35
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710301
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  • 36
    Digitale Medien
    Digitale Medien
    Electron microscopy of the leucocytes of the typhlosole in ammocoetes, with special attention to the antibody- producing cells (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 87-100 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In an attempt to determine the role in the immune responses of the typhlosole, a hematopoietic tissue along the ventral wall of the larval lamprey Lampetra reissneri, scanning and transmission electron microscopic observations were made on ammocoetes hyperimmunized with sheep red blood cells. Besides including the cells of the erythrocyte series, this tissue also contained the following leucocytes forming an amorphous parenchyma: the cells of the granulocyte series, the most predominant cell type, possessing a markedly lobed nucleus and membrane-bounded granules of various sizes; the macrophages possessing primary and secondary lysosomes and long lamellipodia on the cell surface; the lymphocytes of a large nucleocytoplasmic ratio with a number of long, spiky microvilli, constituting a major type of rosette-forming (antigen-binding) cells; and the plasma cells possessing highly extended cisternae of rough endoplasmic reticula that are characteristic of the higher vertebrates. The immunoperoxidase technique, which employs rabbit antibodies against lamprey immunoglobulin, proved that these plasma cells do contain immunoglobulin. These results strongly indicate that the typhlosole of the larval lamprey, besides functioning as a hematopoietic tissue, is actively involved in the antibody responses. It is also stressed that the plasma cell occurs in the most primitive vertebrates as an immunologically competent cell.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730108
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  • 37
    Digitale Medien
    Digitale Medien
    Limb regenerative capacity of four species of Japanese frogs of the families hylidae and ranidae (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 129-135 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The regenerative capacity of limbs was investigated by amputation of limbs at the zeugopodium in postmetamorphic froglets and adults of various sizes in four species of Japanese frogs, all of which showed some regeneration at these ages. In Hyla arborea japonica and Rana brevipoda porosa most young froglets regenerated their limbs well; however, the rate of regeneration decreased with the age of amputation, and the limb became nonregenerative in adults. Limbs of adults in Rana rugosa and R. japonica, on the other hand, exhibited good regeneration. All of the regenerates in the four species were heteromorphic, consisting histologically of well-developed cartilaginous rods surronded by connective tissue and skin. Limited development of muscle was appartment in regenerates of the three ranid species. The relations between body size, innervation of limbs, and regenerative capacity are discussed.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730202
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  • 38
    Digitale Medien
    Digitale Medien
    Functional morphology of the head of the inertial suction feeding butterflyfish, Chaetodon miliaris (perciformes, chaetodontidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 283-312 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The structure and mechanism involved in jaw movements are described for an inertial high-speed suction feeding fish, Chaetodon miliaris. Jaw biomechanics were studied by (1) manipulation of live and fresh-killed specimens, (2) electrical muscle stimulation of anesthetized live specimens, (3) connective tissue severance experiments of fresh-killed and live anesthetized specimens, and (4) cine photography of live unimpaired and surgically impaired specimens.Three couplings appear to be involved in jaw opening: a levator operculi-opercular-interopercular-mandible coupling; and epaxial complex and/or hypaxial/sternohyoideus complex-hyoid apparatus-uncontracted protractor hyoideus-mandible coupling. Jaw opening, protrusion, closing of the protruded mouth, and jaw retraction occur in 60-110 msec. Jaw protrusion coincides with mandible depression during opening of the mouth. Closure of the protruded mouth is apparently the result of contractions of pars A1 and A2 of the adductor mandibulae muscle. Pars A3 and Aw may induce retraction of the jaws in the closed-protruded state. Jaw closure in the retracted, nonprotruded state may involve all branches of the adductor mandibulae.The importance of these findings is discussed in light of previous studies as are some proposed functions of jaw protrusion in this species.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740305
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  • 39
    Digitale Medien
    Digitale Medien
    Arterial retia related to supply of the central nervous system in two small toothed whales- narwhal (Monodon monoceros) an beluga (Delphinapterus leucas) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 41-56 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: We have studied the comparative anatomy of arterial plexuses (retia mirabilia) related to supply of the central nervous system in two closely related species of toothed whales - narwhal (Monodon monoceros) and beluga Delphinaterus leucas). In both species, retia originate from major vessels in the neck, thorax, and lumbar regions, then extend into the neural canal and cranium to supply the spinal cord and brain. The system generally consists of arteries embedded in á matrix of fatty connective tissue. Constituent vessels are only occasionally reated to veins or venous sinuses. Though retial anatomy is similar in the two species, there are two related features that appear species specific: (1) amount of retia originating from the supreme intercostal arteries and (2) thoracic retial size. Both are larger in the narwhal, as are values for hematocrit and hemoglobin concentration, which, in this study, we use as indices of diving ability. Our data are consistent with the hypothesis that the retia are in some way linked to diving ability. The nature of this link is not known; however, we discuss our results in the context of the most popular hyotheses of retial function.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740105
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  • 40
    Digitale Medien
    Digitale Medien
    Transformations of osteoclast phenotype in ia rats cured of congenital osteopetrosis (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 141-147 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The reduced bone resorption characteristic of osteopetrosis is accompanied in the incisors-absent (ia) rat mutation by a significant increase in osteoclasts of inactive (mutant) phenotype. Restoration of bone resorption in ia rats by transfer of spleen cells from normal littermates is preceded by a transformation of osteoclasts from mutant to normal phenotype.In this investigation the proportions of osteoclasts of normal phenotype have been determined by light microscopy in untreated ia and normal rats and in ia rats treated with various cell populations from normal rats. Significant increases in numbers of osteoclasts of normal phenotype were seen in the mutant skeleton soon after cell treatments that eventually restored bone resorption and cured the disease. No changes in osteoclast phenotype were seen after cell transfers that did not cure the disease.These data establish transformation of osteoclast phenotype as an early event in the recovery from osteopetrosis and suggest that determination of osteoclast phenotype is a reliable predictor of the success of normal cell populations to restore bone resorption in this mutation.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740203
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  • 41
    Digitale Medien
    Digitale Medien
    Cytological characterization of the germinal line during testicular differentiation in the lizard Liolaemus gravenhorsti (gray) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 169-184 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The gross morphology, histology, and ultrastructure of Liolaemus gravenhorsti gonads prior to and after differntiation are described. Special emphasis has been given to characterization and changes of the germ cell line throughout intrauterine development and 3 days postpartum.During the pregonadal stage, the primordial germ cell migrates toward gonadal rudiments by way of the mesenchyme. These cells can easily be identified by their great size, voluminous and lobulated nucleus, great quantities of yolk platelets, microtubules, and numerous lipid inclusions. In the undifferentiated gonad, the germ cells (type 1 gonocytes) have an ovoid or spherical shape and autodigestion of yolk platelets, great development of Golgi complex, and mitochondrial aggregation, though fewer liposomes, pseudopodes, and microtubules were noted. Concomitantly with the beginning of mitosis, a third type of germ cell appears, the type 2 gonocytes, which are smaller, with poorly defined membranous systems in various degrees of involution. The seminiferous cords are organized when somatic cells of the medullar portion of the gonad surround type 1 gonocytes. Germinal cells are centrally localized in the cords. Near birth many gonocytes migrate toward the basal lamina of cords and differentiate into spherical prespermatogonia, with few organoids. Sertoli cells eparate them from the basal lamina. In advanced pregnancy, Leyding cells become numerous with morphology typical of androgen-producing cells.
    Zusätzliches Material: 30 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740206
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  • 42
    Digitale Medien
    Digitale Medien
    A forebrain atlas and stereotaxic technique for the lizard, Anolis carolinensis (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 217-236 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A forebrain atlas and stereotaxic neurosurgical techniques were developed for use in anatomical and behavioral experiments on the green anolis lizard (Anolis carolinensis). Green anoles are convenient and robust experimental subjects with a rich behavioral repertoire, the social components of which are partly under hormonal control.The technique and atlas were devised to conduct neuroethological investigations of the effect of lesions on species-typical display behavior. The atlas consists of 12 transverse sections from an average size adult male. The figures (4-15) are based on Nissl material and supplemented with fiber-stained material from adjacent sections. They appear at the end of the article. Limitations on the accuracy of stereotaxic coordinates are discussed and tables of correlative nomenclature for principal telencephalic and diencephalic nuclei are provided.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740210
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  • 43
    Digitale Medien
    Digitale Medien
    Structure and cytochemistry of the silk glands of the mygalomorph spider Antrodiaetus unicolor (araneae, antrodiaetidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 269-274 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Dissection and a variety of absorption and fluorescent cytochemical methods have demonstrated that Antrodiaetus unicolor females have only one type of silk gland and spigot and, consequently, the simplest silk production system of any spider yet investigated histochemically. The small spherical to pear-shaped glands are grouped into four clusters, each cluster serving one of the four spinnerets. The spigots are long, slender, and slightly bent distally. Although all gland cells are structurally similar, each gland simultaneously produces two different secretory products, the secretion of the distal hemisphere being rich in basic protein and sulfhydryl groups, and the proximal hemisphere secretion being an acidic protein containing a high concentration of histochemically demonstrable C-terminal carboxyl groups. The two products remain segregated as they pass through the duct, where the acidic protein forms a thin outer layer around a core of basic protein. It is suggested that this segregation may persist in the silk strand after it exits from the spigot and that the outer acidic protein may be an adhesive agent.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740303
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  • 44
    Digitale Medien
    Digitale Medien
    Evolution of the vestibulolateral lobe of the cerebellum in electroreceptive and nonelectroreceptive teleosts (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 335-348 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The organization of the vestibulolateral lobe of the cerebellum is described in electroreceptive and closely related nonelectroreceptive teleost fishes. The vestibulolateral lobe includes an eminentia granularis and a lobus caudalis. The eminentia granularis is a lateral line-recipient, granule cell zone which in weakly electric fish (i.e., electroreceptive fish with an electric organ) has anterior and posterior divisions associated respectively with a mechanoreceptive medial medullary nucles and an electroreceptive lateral line lobe. A lobus caudalis includes a separate granule cell zone - the pars medialis, a molecular layer, and large Purkinje-like cells. Compared with weakly electric mormyrids, the pars medialis is hypertrophied in weakly electric gymnotoids and electroreceptive silurids. However, the pars medialis is also hypertrophied in nonelectroreceptive teleosts, suggesting it is a granule cell zone not associated with electroreception and perhaps the lateral line system.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740307
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  • 45
    Digitale Medien
    Digitale Medien
    Ultrastrucuture of the fat body of the reproductive pair in higher termites (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 313-322 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The fine structure of the fat body of the higher termite king and queen has been studied both in species with (Macrotermes bellicosus, M. subhyalinus) and without (Cubitermes fungifaber) tracheal rosettes. There is a very pronounced sexual dimorphism. The adipocytes of the queen are highly specialized for protein synthesis and secretion; they store only a small quantity of reserves. The adipocytes of the king are not specialized in protein synthesis, but accumulate large amounts of reserve substances. The previously proposed different functions of the termite queen's fat body are discussed; it appears to be mainly concerned with vitellogenesis.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720306
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  • 46
    Digitale Medien
    Digitale Medien
    The ovary of Fundulus heteroclitus (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 1-16 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Scanning and transmission electron microscopy, together with dissection and light microscopy, have produced heretofore unavailable structural detail of the ovary of Fundulus heteroclitus. Structural and functional interrelationships among developing follicles and other histological elements, particularly as they might relate to vascularization of follicles, oocyte development, and ovulation, are described and discussed. Mature eggs, ovulated into the ovarian lumen, accumulate in the posterior “ovisac” region of the ovary prior to oviposition. This “ovisac” region is thin-walled and apparently nongerminal. The temporary retention of ovulated eggs permits cyclical oviposition even though oogenesis and ovulation are asynchronous. The histological differences between the ovisac and the anterior ovigerous of the ovary are described. The lumenal epithelium of the ovisac displays a localized population of unusual cells with long cytoplasmic extensions. The ultrastructure of these cells suggests that they might function in the transport of ovulated eggs into the oviduct and/or in secreting the substance (“jelly”) which forms the surface coat of extruded eggs.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730102
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  • 47
    Digitale Medien
    Digitale Medien
    Setiferous structures of male coleoptera (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 43-72 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A scanning electron microscopy study was made of the male setiferous sex patches and analogous structures in 11 families of Coleoptera (Anthribidae, Bruchidae, Ciidae, Cleridae, Coccinellidae, Dermestidae, Leiodidae, Ptinidae, Staphylinidae, Tenebrionidae, and Ostomatidae). These secondary sexual characters appear to have several features in common including relatively long, often ridged, setae, cuticular ducts (frequently cribriform pore plates), and the production of a secretion. It is suggested that these structures may all be concerned with the production, release, and dissemination of pheromones.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730106
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  • 48
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730201
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  • 49
    Digitale Medien
    Digitale Medien
    Synganglial and neurosecretory morphology of female Ornithodoros parkeri (cooley) (acari: Argasidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 159-177 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Single esophageal and paired cheliceral, palpal, pedal (I-IV), and opisthosomal nerves enter the synganglion and form specific neuropilar ganglia. The ganglia are integrated by a complex series of commissures and connectives. Eighteen paraldehyde-fuchsin-positive neurosecretory regions, which vary greatly in size and amount of granular neurosecretory material, are each associated (one or more) with neuropilar ganglia. Presumably transport of neurosecretory materials to target tissues occurs through axonal pathways, perineurial-neural lamella associations, and the neurohemal retrocerebral organ complex.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730204
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  • 50
    Digitale Medien
    Digitale Medien
    Rosette glands in the gills of the grass shrimp Palaemonetes pugio. II. Premolt ductule reformation: Replacement of ciliary processes by cytoplasmic processes in relation to gland maturation (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 69-77 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The events associated with premolt reformation of the cuticularized ductule in the underdeveloped (immature) branchial rosette glands, which are common in the gills of small (14-18 mm, total length) grass shrimp, are described and contrasted with the events of ductule reformation in the fully developed (mature) resette glands most common in larger shrimp. In immature rosette glands, two ciliary processes emerge from each of the component secretory cells and ascend into the basal luminal region of the old ductule. Subsequently a new ductule is formed around the old ductule, and the ciliary processes disappear, either because of degeneration or retraction. The transitory ciliary processes appear to prevent the old ductule from collapsing during the formation of a new ductule. Such transitory ciliary processes, however, are not found in association with premolt ductule reformation in the mature rosette glands; in their place are seen a number of microvilli-like cytoplasmic processes, which emanate from the apices of the secretory cells and from the channels of the central cell. These cytoplasmic processes in mature glands, like the ciliary processes in immature glands, are transitory and appear to prevent the collapse of the old ductule.Cytoplasmic processes comparable to those in mature glands, but relatively few in number and originating only from the secretory cells, are seen together with ciliary processes in some immature glands. The relative abundance of cytoplasmic processes in the mature glands, coupled with the observation that transitory ciliary processes occur in immature glands but not in mature glands, suggests that, during glandular maturation, transitory ciliary processes are replaced by transitory cytoplasmic processes.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710105
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  • 51
    Digitale Medien
    Digitale Medien
    Two sperm types in the spermatozeugmata of Tubifex tubifex (annelida, oligochaeta) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 123-136 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The spermatozeugmata (sperm bundles lacking a distinct wall) from the spermathecae of Tubifex tubifex are composed of two different zones: an internal axial cylinder containing conventional spermatozoa and an external cortex composed of modified spermatozoa, tightly packed together. The conventional spermatozoa conform to the classical clitellate scheme: very long and thin with a complex acrosome, a filiform nucleus, small mitochondria, and a flagellum with Y links and β glycogen granules as accessory structures. The modified spermatozoa show “empty” acrosomes, degenerating nuclei, and tails which contain γ glycogen granules. The tails are helically wound around the spermatozeugma and are connected to each other by junctional complexes. The tips of the cortical tails are free and move with a metachronal wave. The presence of two sperm types in tubificids is discussed and a protective function for the modified cortical spermatozoa is proposed.
    Zusätzliches Material: 27 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710202
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  • 52
    Digitale Medien
    Digitale Medien
    Development of the embryonic chick phagocytic system: Intraembryonic erythrophagocytosis induced by phenylhydrazine (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 183-194 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The intraembryonic reticuloendothelial response to phenylhydrazine-induced hemolytic anemia was studied embryonic chicks (days 13-16) by light and electron microscopy and histochemical and biochemical assays for acid phosphatase. Phenylhydrazine was given on day 13 and tissue taken at 2, 5, and 10 h and at 1, 2, and 3 days after injections. The response varied in the three major reticuloendothelial organs. The spleen first demonstrated an increase in erythrophagocytosis that was accompanied by increased acid phosphatase levels. Erythrophagocytosis occurred primarily in the red pulp resulting in increased numbers of macrophages, increased size of macrophages, and retention of erythrocytes, which together combined to enlarge the spleens. By 2 days after phenylhydrazine injection, greatly enlarged macrophages began to migrate into the venous system, where some erythrophagocytosis continued to occur. The liver was also a major erythroclastic organ in which Kupffer cells became increasingly erythrophagocytic. However, erythrophagocytosis began later than in the spleen, and as measured by acid phosphatase levels, the liver was not as effective in removing damaged erythroid cells. Marrow erythrophagocytosis was only slightly enhanced; however, the marrow responded by increasing its production of red blood cells. Thus, the intraembryonic reticuloendothelial organs of the embryonic chick responded to phenylhydrazine-induced hemolytic anemia in much the same manner as might be expected of the adult bird.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710206
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  • 53
    Digitale Medien
    Digitale Medien
    The structure of the chambered nautilus siphuncle: The siphuncular epithelium (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 5-22 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The siphuncle of the chambered nautilus (Nautilus macromphalus) is composed of a layer of columnar epithelial cells resting on a vascularized connective tissue base. The siphuncular epithelium taken from chambers that have not yet begun to be emptied of cameral liquid has a dense apical brush border. The great number of apical cell junctions (zonula adherens) compared to the number of nuclei suggests extensive interdigitation of these cells. The perinuclear cytoplasm of these preemptying cells is rich in rough endoplasmic reticulum. The siphuncular epithelium of both emptying and “old” siphuncle (which has already completed emptying its chamber) both show little rough endoplasmic reticulum but do contain extensive systems of mitochondria-lined infoldings of the basolateral plasma membranes. Active transport of NaCl into the extracellular space of this tubular system probably entrains the water transport involved in the chamber-emptying process. Both emptying and old siphuncular epithelium also show large basal infoldings (canaliculi) continuous with the hemocoel, which appear to be filled with hemocyanin. The apical cell junctions of emptying and old siphuncular epithelium contain septate desmosomes that may help to prevent back-flow of cameral liquid into the chambers.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720103
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  • 54
    Digitale Medien
    Digitale Medien
    Rosette glands in the gills of the grass shrimp, Palaemonetes pugio. I. Comparative morphology, cyclical activity, and innervation (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 41-67 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Two types of exocrine rosette glands (called type A and type B), located in the gill axes of the grass shrimp Palaemonetes pugio, are described. The type A glands are embedded within the longitudinal median septum of the gill axes, whereas the type B glands typically project into the efferent hemolymph channels of the gill axes. Although both glands have certain common characteristics (i.e., a variable number of radially arranged secretory cells, a central intercalary cell, and a canal cell that forms the cuticular ductule leading to the branchial surface), they differ in the following respects. The type B gland is innervated, but the type A gland is not; axonal processes, containing both granular (ca. 900-1300 Å) and agranular (ca. 450-640 Å) vesicles, occur at a juncture between adjacent secretory cells and the central cell of the type B gland. The secretory cells of type A and type B glands differ in their synthetic potential and membrane specializations. These differences are more pronounced in well-developed, mature glands, most frequently encountered in larger (24-28 mm, total length) grass shrimp, than in the underdeveloped, immature glands that are most abundant in smaller (14-18 mm, total length) grass shrimp. Thus, in mature glands, the secretory cells of the type A rosette glands are characterized by extensive RER, abundant Golgi, and numerous secretory granules, whereas the secretory cells of the type B gland are characterized by extensively infolded and interdigitated basal plasmalemmas and by the presence of numerous mitochondria. In general, both types of glands exhibit increased secretory activity soon after ecdysis. The central and canal cells in both glands seem to have a role in the modification of the secreted materials. The possible functions assigned to the type A gland and the type B gland include phenol-oxidase secretion and osmoregulation, respectively.
    Zusätzliches Material: 48 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710104
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  • 55
    Digitale Medien
    Digitale Medien
    Transformation of the intestinal epithelium of the larval anadromous sea lamprey Petromyzon marinus L. during metamorphosis (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 89-117 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The events in the transformation of the intestine of the larval lamprey into the adult intestine were followed through the seven (1-7) stages of metamorphosis in anadromous Petromyzon marinus L. Light and electron-microscope observations demonstrated that the processes of degeneration, differentiation, and proliferation are involved in the transformation. In the anterior intestine, degeneration of cells and the extrusion of others into the lumen results in the disappearance of secretory (zymogen) cells and the decline in numbers of endocrine and ciliated cells. Larval absorptive cells, with a prominent brush border, are believed to dedifferentiate into unspecialized columnar cells with few microvilli. Degeneration and removal of cells occurs by both autophagy and heterography and cells extruded into the lumen in the anterior intestine are phagocytosed by epithelial cells of the posterior intestine. The loss of epithelial cells during transformation results in the folding and degradation of parts of the basal lamina and in an extensive widening of the lateral intercellular spaces in all parts of the intestine. As metamorphosis is a nontrophic period of the lamprey life cycle, the possible morphological effects of starvation on the intestinal epithelium are discussed.The development of longitudinal folds is a consequence of the events of metamorphic transformation of the intestinal mucosa. Although an interaction between the epithelium and the underlying tissues is believed to be importent, the actual mechanism of fold development is unknown.The intestinal epithelium of adult lampreys develops from surviving cells of the larval (primary) epithelium. Unlike the situation in amphibians, there does not appear to be a group (nest) of undifferentiated larval cells which differentiate into the adult (secondary) epithelium. Instead, in lampreys, columnar cells that persist through the degradative processes seem to be the source of absorptive and ciliated cells and probably are responsible for mucous and secretory cells.Preliminary observations indicate that the intestinal epithelium of feeding adults is specialized into an anterior region which liberates a secretion, absorbs lipid, and possesses the machinery for ion transport. A posterior region absorbs lipid, secretes mucus, and likely is involved in some protein absorption.
    Zusätzliches Material: 29 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710107
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  • 56
    Digitale Medien
    Digitale Medien
    The organization of the octavolateralis area in actinopterygian fishes: A new interpretation (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 159-181 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The octavolateralis area of actinopterygian fishes can be subdivided into a dorsal lateralis area composed of first-order lateral line nuclei, and a ventral octavus area composed of nuclei receiving first-order input from the eighth nerve. Three patterns of organization of the lateralis area are recognized in the present study. The organization of this area in polypteriforms and chondrosteans is similar to that in chondrichthyans. On the basis of recent studies in chondrichthyans (McCready and Boord, '76; Boord and Campbell, '77; Bodznick and Northcutt, '80), it is hypothesized that this pattern reflects the subdivision of the lateral line system into mechanoreceptive and electroreceptive portions. As petromyzontid agnathans also share this pattern of organization, it is hypothesized that they are elecroreceptive. The lateralis area of holosteans and nonelectroreceptive teleosts exhibits a second organizational pattern that is hypothesized to reflect the loss of the electroreceptive portion of the lateral line system; it is suggested that electroreception was lost sometime between the chondrostean and teleostean radiations. Each group of electroreceptive teleosts is believed to have evolved electroreception independently (Bullock, '74), a situation that is reflected centrally by a third organizational pattern within the lateralis area, which is distinctly different from that of early radiations of electroreceptive fishes.The octavus area of actinopterygians exhibits two patterns of organization-that of polypteriforms, chondrosteans, and holosteans, and that of teleosts. The functional significance of these patterns has yet to be elucidated.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710205
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  • 57
    Digitale Medien
    Digitale Medien
    Differentiation of Acmaea digitalis oocytes with special reference to lipid-endoplasmic reticulum-annulate lamellae-polyribosome relationships (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 225-243 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: During initial stages of oogenesis, many nucleoli are adpressed to the inner membrane of the nuclear envelope. Small nucleolar fragments appear to traverse the pores of the nuclear envelope and accumulate in the perinuclear ooplasm as fibrogranular bodies. Mitochondria become closely associated with some of the fibrogranular bodies. In addition to ribosomes and polyribosomes that are present in small oocytes, lamellae of rough-surfaced endoplasmic reticulum (rER) increase greatly in number during early stages of differentiation. Some individual lamellae are attached at their ends to the outer membrane of the nuclear envelope. Many parallel lamellae of rER are then encountered as well as numerous circular profiles consisting of concentric loops of rER. Soon after the differentiation of the extensive system of rER, lipid droplets or spheres appear in the ooplasm and they are initially surrounded by many circular, concentric lamellae of rER. Initially, the number of concentric lamellae of rER surrounding a lipid droplet may vary from less than a dozen to more than two dozen. During middle and late phases of vitellogenesis, most of the lipid spheres that comprise the most numerous and significant component of the yolk are surrounded by only one or two concentric lamellae of rER (in some cases the lamellae are part rough-surfaced and part smooth-surfaced). In addition, annulate lamellae are then observed to be associated with a portion of the lipid droplet surface. The number of annulate lamellae that extend focally from the lipid sphere distally into the cytoplasm is variable; often two or three to more than a dozen lamellae. Small granules, many of which range from 6 to 12 nm and thin fibrils (approximately 2-3 nm in width) may be associated with the annulate lamellae. In addition, polyribosomes frequently appear to be continuous with the pore-associated material of the annulate lamellae. The ends of some annulate lamellae may extend as lamellae of the rER. The morphologic relationships and relationships and variations observed between the lipid droplets, rER, annulate lamellae, and polyribosomes during lipidogenesis in this oocyte are interpreted to support a recent hypothesis (Kessel, 1981a,b) that the pores of annulate lamellae may be involved in some manner with the processing of ribosomal subunits or precursors into functioning polyribosomes, and that their appearance in specific association with the surface of many lipid spheres and rER in the oocyte late in vitellogenesis may be related to the formation of additional functional polyribosomes necessary to complete the final synthesis of many lipid droplets that are present in the ooplasm of the full-grown oocyte.
    Zusätzliches Material: 43 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710210
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  • 58
    Digitale Medien
    Digitale Medien
    Types of neurons and synaptic connections at hypostome-tentacle junctions in Hydra (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 119-128 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Using transmission electron microscopy of thin sections we have examined neuronal concentrations at hypostome-tentacle junctions in Hydra littoralis. A total of 194 ganglion cells were counted in 587 serial thin sections of a single hypostome-tentacle junction. We found two distinct types of ganglion cells: those with and those lacking stereocilia. The majority of the neurons observed lacked stereocilia; in a single hypostome-tentacle junction only 37% of the ganglion cells possessed a kinocilium surrounded by rodlike stereocilia. Most of the ganglion cells (55%) were clustered together in the oral or upper epidermis of the hypostome-tentacle junction: Nineteen percent were in the lateral and 26% in the aboral or lower epidermis. The two types of ganglion cells did not differ significantly in their distribution. Both types of ganglion cell had synaptic contacts with other neurons and with epitheliomuscular cells. More than 85% of the neuroneuronal and 61% of the neuroepitheliomuscular cell synapses were located in the oral epidermis of a hypostome-tentacle junction. In addition, two-way chemical synapses and a gap junction between neurons were observed at hypostome-tentacle junctions. Our morphological evidence of synaptic connectivity in neuronal clusters at hypostome-tentacle junctions suggests that primitive ganglia are present in Hydra.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730110
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  • 59
    Digitale Medien
    Digitale Medien
    Abnormal development of vertebrae in paralyzed chick embryos (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 179-184 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Ventral bars, cartilaginous projections from the ventral aspect of the synsacrum that contact and form a joint with the ilium, were found in all normal chick embryos of age E9 and older. Bars were absent in a number of embryos which had been paralyzed from age E4 by the use of the acetylcholine receptor blocker α-bungarotoxin. They were also absent in some embryos that had been paralyzed between ages E4 and E10 but allowed to move thereafter. The bars, already formed, remained present in a third group of embryos in which paralysis was initiated at age E10. Apparently, normal embryonic movements induce the formation of bars. In support of this conclusion is the observation that two of three embryos which had had their hindlimb buds amputated at age E3 lacked bars. In these embryos with amputations, the ilium was present at least in part, but the forces exerted on the region where the bars develop would have been greatly reduced because of the lack of hind limb musculature. It is concluded that the bars, which form part of the iliosynsacral joint, are induced epigenetically by normal embryonic movements.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730205
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  • 60
    Digitale Medien
    Digitale Medien
    Development of the crayfish retina: A light and electron microscopic study (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 101-118 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The development of the crayfish retina was examined in embryos and first, second and third instars with both and light and electron microscope. Light microscopic observations indicate that differentiation begins at the posterior portion of the optic disc and progresses in an anterior direction. Development of screening pigment, dioptric elements, and rhabdoms all parallel this posterior to anterior gradient in the retina. Tracer studies in early embryos reveal that the retina is separated from the proximal neuropil regions by a distinct vascular space. This observation suggests that the source of new cells for the retina may not be the more proximal cell proliferation zone as previously indicated. It is proposed that mitotic activity within the retina and/or differentiation of cells from the anterior surface layer of the eye may be sources for addition of new cells to the retina. Proto-ommatidial clusters of seven retinula cells occur very early at the posterior region of the embryonic retina. Initially the receptor cells extend throughout the entire thickness of the retina, but later they withdraw from beneath the cornea to occupy only the proximal portion of the retina. Microvilli of the rhabdom arise from the centrally opposed membranes of the retinula cells in each cell cluster. Each new microvillus contains a core of fine filaments which extend out into the cytoplasm at its base. As development of the microvilli continues, the core filaments appear to be lost or altered, but the cytoplasmic bundles at the base of the microvilli persist.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730109
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  • 61
    Digitale Medien
    Digitale Medien
    A model for comparison of masticatory effectiveness in primates (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 139-149 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A model is presented to express how effectively animals increase the exposed surface area of their food by chewing. It includes a coefficient of masticatory effectiveness (E) the value of which increases with effectiveness of exposing new food surface area with each chew. Humans and other species of primates differ significantly in their values of E; among the nonhuman primates studies, Lemur catta has a higher coefficient than Lemur fulvus, and both have higher coefficients than either Varecia variegatus or Galago crassicaudatus argentatus. The differences among the coefficients to these prosimians are correlated with variations in specific features of the molar morphology.Of six lower molar shearing crests considered, the relative length of the post-metacristid correlates most highly with the coefficient of masticatory effectiveness for the prosimian species. Also, among comparable-sized prosimians, E correlates significantly with the absolute postmetacristid length. Both these findings indicate that the relative size of molar shearing crests is related significantly to how effectively an animal chews its food. There are also implications for an adaptation to a high-fiber diet.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720202
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  • 62
    Digitale Medien
    Digitale Medien
    A structural analysis of the freshly extruded spermatophore from the lobster, Homarus americanus (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 193-207 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Freshly extruded spermatophores from the lobster, Homarus americanus, were examined using light microscopy and scanning and transmission electron microscopy. The tubular spermatophore is trifoil in shape with two lobes tapered laterally from a third lobe situated ventrally. It is comprised of sperm surrounded by three acellular investments: (1) a primary spermatophore layer, (2) an intermediate layer, and (3) an outer bounding layer. The sperm are packed into a continuous tube contained largely within the ventral lobe and are embedded in a matrix of moderate electron density. The primary spermatophore layer is uniformly thick around the sperm mass and contains at its peripheral margins both ring structures and crystals in an amorphous matrix. The intermediate layer is thicker dorsally than ventrally. Dense granules dominate the ventral half of the intermediate layer while inclusions populate the dorsal half; both react positively to the periodic acid-Schiff (PAS) technique. The innermost portion of the outer bounding layer is composed of parallel fibrils; a flocculent material is present peripherally. This flocculent substance is presumed to impart stickiness to freshly extruded spermatophores. These observations provide a basis for the future understanding of the mechanisms involved in long-term storage of sperm in spermatophores.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720206
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  • 63
    Digitale Medien
    Digitale Medien
    The early embryonic development of the primitive moth, Neomicropteryx nipponensis lssiki (lepidoptera, micropterygidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 259-269 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This paper describes the early embryonic development of Neomicropteryx nipponensis from oviposition to the formation of the inner layer. Newly laid eggs are covered with many hygroscopic, gelatinous masses. The chorion is composed of a porous, spongy exochorion of variable thickness and of a thin endochorion. The eggs have a very thin periplasm and contain large amounts of yolk made of proteid and fatty yolk droplets. The processes of maturation division, fertilization, and cleavage are similar to those commonly found in lepidopteran eggs. The blastoderm of Neomicropteryx is very thin in comparison with that of other lepidopteran eggs. The small circular germ disk is formed on the ventral egg surface. It then invaginates deeply into the yolk to form a sac-shaped germ rudiment. The formation of the germ rudiment and of the embryonic membranes resembles that of swift moths, Endoclita (suborder Monotrysia) and of the caddisfly, Stenopsyche (Trichoptera), but differs from that of ditrysian Lepidoptera. As in other lepidopteran insects, the formation of the inner layer begins after completion of the germ band, which has a bilobed protocephalon and a slender protocorm. Unlike the situation in most lepidopteran eggs, yolk segmentation does not occur in N. nipponensis. During formation of the germ band, hydropyle cells are formed in the dorso-posterior region of the serosa; these are here reported for the first time in the eggs of holometabolan insects.
    Zusätzliches Material: 27 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720302
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  • 64
    Digitale Medien
    Digitale Medien
    Development and metamorphosis of the feeding apparatus of the stone crab, Menippe mercenaria (brachyura, xanthidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 299-312 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Analysis of the feeding apparatus of the stone crab, Menippe mercenaria (Brachyura, Xanthidae), has demonstrated that substantial internal and external morphological alterations occur at metamorphosis and suggests that the mastication of food shifts from the mandibles to the gastric mill at that time. These changes correspond to the changes in environment and diet that take place at metamorphosis, when the previously planktotrophic larvae begin benthic life.A detailed account of the structure and development of the mandibles is presented. The mandibles of all zoeal stages are similar: The incisor process has a series of teeth and denticles and the prominent molar process appears to be well adapted for grinding food. Megalopal mandibles are transitional but have the form that is typical of all subsequent stages: The expanded incisor process is rounded and toothless and the molar process is less prominent and has lost its grinding denticles. The cardiac stomach of the zoeal stages has no gastric mill; the medial and lateral teeth of the mill first appear in the megalopa.A very simple procedure is described for preparing larval mandibles for scanning electron microscopy using the molted exoskeletons from larval rearing experiments.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720305
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  • 65
    Digitale Medien
    Digitale Medien
    The sensory systems and feeding behavior of leafhoppers. I. The aster leafhopper, Macrosteles fascifrons stål (homoptera, cicadellidae) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 361-379 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of the sensilla, and other structures, within the stylets and precibarium of Macrosteles fascifrons were examined by transmission and scanning electron microscopy. Precibarium is a new term, defined here, for the canal that precedes the cibarium inside the leafhopper head. Within the precibarium are found 20 chemosensilla and a previously undescribed structure, the precibarial valve. Twelve mechanosensilla, three in each stylet, are found within the maxillary and mandibular stylets. The relationship between all of these structures and feeding by the insect is detailed in a feeding mechanism hypothesis. It is concluded that leafhoppers (and probably all homopterans) utilize the precibarial chemosensilla alone for gustatory discrimination, the stylet sensilla for proprioception, and the precibarial valve for regulation of fluid uptake and compartmentalization of the sensilla.
    Zusätzliches Material: 22 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720310
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  • 66
    Digitale Medien
    Digitale Medien
    Histological and enzyme histochemical studies on the nephrons of the freshwater fishes, Cyprinus carpio and Carassius auratus (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 29-33 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The nephrons of carp (Cyprinus carpio) and goldfish (Carassius auratus) were examined histologically and also histochemically for enzymes. In both species the distal and collecting tubules have much wider lumens than do the other renal tubules; thus urine probably flows more slowly in these larger tubules. Enzyme histochemistry shows that epithelium of the neck and proximal and intermediate tubules respires anaerobically. whereas that of the distal and collecting tubules respires aerobically. The distribution of Na-K-ATPase in the distal and collecting tubules indicates that they also transport sodium actively. The slow flow of urine and the energy produced by aerobic metabolism probably increase the efficiency of active transport.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730104
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  • 67
    Digitale Medien
    Digitale Medien
    Ultrastructural localization of glucose-6-phosphatase and alkaline phosphatase in the vaginal epithelium of rat (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 1-10 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The effect of ovarian hormones on the activities of glucose-6-phosphatase and alkaline phosphatase in the vaginal epithelium was studied in immature and ovariectomized rats, using ultracytochemical techniques. Comparative studies were done on normal rats at the luteal phase and on day 14 of pregnancy.Various vaginal cells show different degrees of response to progesterone and diethylstilbestrol (DES) with regard to glucose-6-phosphatase activity. Intense glucose-6-phosphatase activity was observed in the cisternae of granular endoplasmic reticulum (rER), Golgi saccules and vesicles, and nuclear envelope of both basal cells and stromal cells of progesterone treated rats, whereas in the basal cells and stromal cells of DES-treated and control animals the enzyme was totally lacking. Detectable glucose-6-phosphatase activity was also observed, however, in the rER cisternae and Golgic complex of keratohyalin-secreting squamous intermediate cells of the vaginal epithelium of DES-treated rats. Alkaline phosphatase was observed in the plasma membranes of various cell types of vaginal epithelium in the normal, progesterone-, and DES-treated rats, Alkaline phosphatase was also found on the limiting membranes of secretory granules of mucocytes in animals at the luteal phase and during pregnancy. DES and progesterone in the doses used did not affect alkaline phosphatase activity in the rat vagina. Overall, progesterone enhances glucose-6-phosphatase activity in basal cells of the rat vagina prior to completion of mucification. Alkaline phosphatase was found in all cells involved in mucin secretion.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710102
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  • 68
    Digitale Medien
    Digitale Medien
    Morphology and distribution of chromaffin cells in the adrenal gland of cordylidae (Reptilia, Sauria): A comparative study (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 79-88 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The distribution of the adrenaline and noradrenaline chromaffin cells in the adrenal glands of 10 members of the family Cordylidae have been examined. In the genus Gerrhosaurus, all the catecholamine cells lie on the surface of the adrenal gland, forming a continuous envelope of one or two layers of cells that mainly contain noradrenaline (NA). In the genus Platysaurus, the chromaffin envelope is intermittent. There are relatively large tracts of interspersed interrenal tissue containing some adrenaline cells (A). Islets of chromaffin cells are scattered between these interrenal tracts. In the genus Pseudocordylus and the genus Cordylus, the superficial chromaffin cells tend to gather into a multilayered dorsal mass, containing mainly NA cells. Inside the interrenal parenchyma, there are always numerous chromaffin islets, containing mainly A cells.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710106
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  • 69
    Digitale Medien
    Digitale Medien
    Morphometric studies on tenuissimus muscle spindles in the cat (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 137-150 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Muscle spindles were studied histochemically in serial transverse sections of 42 cat tenussimus muscle specimens. Staining for myofibrillar adenosine triphosphatase was employed to identify nuclear bag1, nuclear bag2, and nuclear chain intrafusal muscle fibers. The nuclear chain fibers were further subdivided into three categories according to their polar length and the intensity of their staining for nicotinamide adenine dinucleotide tetrazolium reductase. A total of 430 spindle poles were surveyed. The mean spindle content of bag1, bag2, and chain fibers was established. The mean polar length of intrafusal fibers as well as that of the intracapsular and extracapsular spindle regions was determined. A cholinesterase (ChE) staining technique was used to demonstrate the termination sites of motor axons along intrafusal fibers. Two types of circumscribed ChE deposits, the “rim” and the “plate,” occurred on the fibers. The nuclear chain fibers usually carried both the ChE rims and plates, while most nuclear bag fibers displayed only the plates. The ChE plates were assessed in term of their appearance, staining intensity, length, and location along the fibers. The mean number of ChE plates found along the fibers was established for each of the various intrafusal fiber types.These histochemical observations are discussed with regard to the current concepts of cat spindle morphology and motor innervation. The results suggest a degree of predictability in the spindle fiber content and in the distribution of motor nerve terminals along intrafusal muscle fibers, at least in the tenuissimus muscle.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710203
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  • 70
    Digitale Medien
    Digitale Medien
    An ultrastructural analysis of isolated basement membranes in the acellular renal cortex: A comparative study of human and laboratory animals (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 195-211 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Freshly harvested kidneys from New Zealand white rabbits, Sprague-Dawley white rats, rhesus monkeys, and transplant-quality human kidneys were used in this study. Minced renal cortical tissue blocks (〈2 mm3) were treated with 1 mM EDTA, 3% Triton X-100, 0.025% DNAse, and 4% sodium deoxycholate in an effort to remove all cellular elements and leave the extracellular matrix (ECM) intact. These preparations showed remarkable structural preservation and all components of the ECM, including basement membranes (BMs), maintained their in vivo histoarchitectural relationships. By light microscopy, at least four major BM types were recognizable, including Bowman's capsular BM (BCBM), tubular BM (TBM), glomerular BM (GBM), and peritubular capillary BM (PTCBM). Scanning electron microscopy demonstrated that, despite the lack of supporting interstitium, GBMs in human, monkey, and rat (and rabbit to a lesser degree) exhibit intrinsic structural rigidity such that their convoluted spheroidal shapes are maintained following cell removal. Transmission electron microscopy showed that major BM types are morphologically heterogeneous and vary markedly within and between species. Randomized measurements showed that isolated BM thicknesses (lamina densa only) compared favorably with those reported in cellular preparations. Mean thicknesses of GBMs were within normal ranges in all species with or without power transformations to reduce right-sided skew of distribution curves. In all species, thickness of BCBM 〉 TBM 〉 GGBM 〉 PTCBM. The striking morphologic heterogeneity of major BM types demonstrated in the acellular renal cortex is not surprising in view of recent biochemical analyses that show that BMs derived from different sources are compositionally disparate. We conclude that BMs should be evaluated and characterized individually and that morphologic definition of isolated BMs is necessary prior to further analysis.
    Zusätzliches Material: 21 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710207
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  • 71
    Digitale Medien
    Digitale Medien
    Morphology of the aedeagal gland of the male mealworm beetle (Tenebrio molitor L.) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 259-281 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The aedeagal gland of male Tenebrio molitor consists of numerous acini containing several secretory units (organules) of three epithelial cells in series. The distal cortical cell and intermediate cell are secretory cells. Secretory products are passed into microvilli-lined extracellular reservoirs. From these storage areas products flow through minute canaliculi and into the efferent ductule. Canaliculi, cuticular trabeculae, and fibrillar material are characteristic features of the efferent ductules within the extracellular reservoirs of secretory cells. After passing from the secretory cells, the efferent ductule penetrates the basal ductule cell. The thin epicuticle that comprises the wall of the ductule is confluent with the epicuticle of the cuticular sheath forming the wall of the genital pocket. Secretory products flow from the cortical cell ductule into the intermediate cell and eventually empty into the genital pocket. A chemical reaction apparently takes place in the intermediate cell ductule, resulting in a frothy secretion product. When released from the ductule, this frothy product forms a foam-like layer that coats the inner wall of the genital pocket. Ultrastructural and probable functional aspects of this gland are described and discussed.
    Zusätzliches Material: 30 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710303
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  • 72
    Digitale Medien
    Digitale Medien
    Structure and evolution of tetraodontoid teeth: An autoradiographic study (pisces, Tetraodontiformes) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 283-292 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: For years teeth of tetraodontoid fishes generally have been considered coalescent even though “coalescence,” which also is found in fishes of other families, has never been well defined. This paper deals with some aspects of coalescence of the teeth in tetraodontoids and attempts to define this condition. The sites of osteodentinogenesis and the mechanisms by which hard tissues are formed, reabsorbed, and abraded during feeding were analyzed from semiserial decalcified sections and from ground sections, as well as from autoradiographs of the premaxilla and dentary bones of Sphoeroides greeleyi. The observations reported here, taken together with other data we have obtained on members of the Tetraodontoidei, permit clear definitions of “tooth” and “supporting bone,” and consequently the structural meaning of coalescence. From these data we hypothesize how coalesced masticatory structures may have evolved in this group.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710304
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  • 73
    Digitale Medien
    Digitale Medien
    Announcement (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 365-365 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710309
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  • 74
    Digitale Medien
    Digitale Medien
    Mastication in the tuatara, Sphenodon punctatus (reptilia: Rhynchocephalia): Structure and activity of the motor system (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 321-353 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The masticatory pattern of Sphenodon punctatus, the sole remaining rhynchocephalian, now restricted to islands off the coast of New Zealand, has been analyzed by detailed anatomy, cinematography, cinefluoroscopy, and electromyography. Food reduction consists of a closing, crushing bite followed by a propalineal sliding of the dentary row between the maxillary and palatine ones. The large, fleshy tongue can be protruded to pick up small prey, and also plays a major role in prey manipulation. The rotational closing movement of the jaw, supporting the basic crushing movement, is induced by the main adductor musculature. It is followed by a propalineal anterior displacement relying heavily on the action of the M. pterygoideus. The fiber lengths of the several muscles reflect the extent of shortening. The most obvious modification appears in the M. pterygoideus, which contains a central slip of pinnately arranged short fibers that act a period different from that of the rest of the muscle; their action increases the power during the terminal portion of the propalineal phase. This also allows the animal to use its short teeth in an effective shearing bite that cuts fragments off large prey.The action of single cusped dentary teeth acting between the maxillary and palatine tooth rows provides a translational crushing-cutting action that may be an analog of the mammalian molar pattern. However, this strictly fore-aft slide does not incorporate capacity for later development of lateral movement.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710307
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  • 75
    Digitale Medien
    Digitale Medien
    Architecture of the hind limb muscles of cats: Functional significance (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 185-195 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Force, velocity, and displacement properties of a muscle are determined in large part by its architectural design. The relative effect of muscle architecture on these physiological variables was studied by determining muscle weight, fiber length, average sarcomere length, and approximate angle of pinnation for 24 cat hind limb muscles. Muscle lengths ranged from 28.3 to 144 mm, whereas fiber lengths ranged from 8.4 to 105.5 mm. Generally, fiber to muscle length ratios were similar throughout a muscle. Estimated angles of pinnation of muscle fibers varied from 0 to 21° with most having an angle of less than 10°. The cross-sectional area of the knee extensors was similar to the knee flexors (16.43 vs. 16.83 cm2) whereas the cross-sectional area of the ankle extensors was more than six times greater than the ankle flexors (18.59 vs. 2.83 cm2). There was a 6.7-fold difference in the maximal force between muscles, when normalized to a constant weight, that could be attributed to architectural features. Rations of wet weight to predicted maximal tetanic tension for each muscle and group were calculated to compare the relative priority of muscle force versus muscle length-velocity for a given mass of muscle. These ratios varied from 0.4 to 4.84. The ratios suggest that velocity and/or displacement is a priority for the hamstrings, whereas force is a priority for the quadriceps and lower leg muscles. As much as a 12.6-fold difference in maximal velocity between muscles can be attributed to differences in fiber lengths. This can be compared to approximately a 2.5-fold difference in maximal velocity reported to occur as a result of biochemical (intrinsic) differences.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730206
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  • 76
    Digitale Medien
    Digitale Medien
    Ultrastructural aspects of mechano- and chemoreceptors in Branchiobdella pentodonta (annelida, oligochaeta) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 237-245 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The surface receptors in Branchiobdella pentodonta consist of “sense buttons” prevalent on the prostomium, isolated sense cells all along the body of the animal, and free nerve endings. The “sense buttons” are uni- and multiciliated neurosensitive elements and supporting cells together with mucus glandular processes and muscle fibers. In the neurosensitive elements the cilia are always surrounded by cytoplasmic extroversion. The cytoplasm of the apical zone has abundant small dense granules, mitochondria, bands of tonofilaments, and microtubules. The cilium of uniciliated elements originates from three short roots. The highly vacuolated support cells surround the neurosensitive elements, separating them from each other. The “sense buttons” appear to be mechanoreceptors and chemoreceptors, and the isolated sense cells tactile mechanoreceptors, as are the free nerve endings. The surface receptors are compared with those of other Oligochaeta and Hirudinea.
    Zusätzliches Material: 15 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730210
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  • 77
    Digitale Medien
    Digitale Medien
    The cellular basis of the aggressive acrorhagial response of sea anemones (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 259-278 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Some sea anemones possess structures called acrorhagi at the base of the tentacles. The acrorhagi are utilized solely for aggression. Acrorhagial aggression involves very exquisite intra- and interspecific recognition. This study examined acrorhagi and putative acrorhagial analogues or homologues in four species of sea anemone. The morphology and ultrastructure of tentacles, pseudoacrorhagi, column vesicles, and verrucae (adhesive column vesicles) differed from that of acrorhagi. Coral capitate tentacles and acrorhagi have different surface morphology, nematocysts, and functions. Besed on morphology, acrorhagi seem more likely to be homologous to tentacles than to verrucae.Acrorhagial nematocyst discharge and ectodermal peeling, the culmination of the response, were shown to require prior acrorhagial expansion in Anthopleura krebsi and Bunodosoma cavernata. A mechanical mechanism is suggested where- by distention of the acrorhagus opens a ciliary pit on the nematocyte surface and exposes the pit wall and microvilli, which may contain the chemoreceptors for the peeling process, including nematocyst discharge. A similar system may also be responsible for changing the threshold of nematocyst discharge in sea anemone tentacles. A case of possible neurosecretion in an anthozoan was also shown in this study.
    Zusätzliches Material: 35 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730303
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  • 78
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740101
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  • 79
    Digitale Medien
    Digitale Medien
    The ultrastructure of spermatogenesis in Labidocera aestiva (copepoda: Calanoida) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 1-15 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The fine structure of spermatogenesis is described for the marine calanoid copepod Labidocera aestiva. The mature spermatozoon is a slightly flattened, disc-shaped cell without a flagellum or an acrosome.Primary spermatocytes in first meiotic prophase are characterized by large nuclei showing progressive condensation of chromatin. The cytoplasm contains free ribosomes, numerous mitochondria, cytoplasmic vesicles, centrioles, and perinuclear nuage. Densely staining cisternae are associated with the nuage of pachytene and diplotene primary spermatocytes. This association may represent the temporary differentiation of an acrosome. Synaptonemal polycomplexes are frequently present in the nuclei of zygotene, pachytene, and diplotene primary spermatocytes. Many of the intercellular bridges which join the germ cells throughout spermatogenesis appear occluded by systems of transverse membranous cisternae. After the second meiotic telophase, spermatids are incorporated into nongerminal accessory cells that may facilitate the release of spermatids from the testis and regulate the rate of spermatogenesis by phagocytosis.During spermiogenesis the mitochondria become closely applied to the nuclear envelope, the nuclear envelope fragments and forms an elaborate membrane complex, a pentalaminar plasma membrane develops, and electron-dense material accumulates on the inner and outer surfaces of the plasma membrane in the mature spermatozoon.
    Zusätzliches Material: 29 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740102
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  • 80
    Digitale Medien
    Digitale Medien
    Hamster nasal glands: Their structure, sialic acid content, and vulnerability to actinomycin D (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 79-94 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study examines the structure of mucosal glands in the walls of the hamster maxillary recess, compares the histochemical appearance of nasal glands to their sialic acid content, and determines the vulnerability of nasal glands to actinomycin toxicity. Observations were made on plastic-embedded tissue with light and transmission electron microscopes. Determinations of total sialic acid in mucosal samples were conducted with thiobarbituric acid. Experimental hamsters were administered 0.2 μg of actinomycin D (IP)/gm body weight/day for five days. Types of granules present in the lateral nasal gland (LNG) and glands of the maxillary recess (MRGs) include: 2.0 μm lightly basophilic, lightly electron-dense granules and 1.5 μm strongly basophilic, electron-dense granules in the same acinar cell type in both the LNG and MRGs; 1.5 μm metachromatic granules in some acinar cells of the LNG; 1.0 μm moderately electron-dense granules in cells of MRG ducts; and 0.7 μm electrondense granules in cells of LNG intercalated ducts. Acid glycoproteins, demonstrable by histochemistry, are present in the LNG but not in the MRGs. However, the total sialic acid content of tissues from MRG tissue is greater than that of other tissues measured. A minor number of LNG acini, those with metachromatic granules, have branching basal cytoplasmic projections. Many dark cells are present in striated ducts of the LNG. Histological alteration due to actinomycin-D toxicity, conspicuous in parotid salivary parenchyma, is greater in MRG than in LNG tissue.
    Zusätzliches Material: 28 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740107
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  • 81
    Digitale Medien
    Digitale Medien
    The structure of the head kidney in the mudskipper, Periophthalmus koelreuteri (pallas) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 121-131 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The head kidneys of adult Periophthalamus koelreuteri contain many functional glomerular nephorns which on the basis of this histochemical study, are indistinguishable from those of the typical opistonephros of marine teleosts. The anterior lobes resemble, in location and in the presence of intertubular erythropoeitic tissue, the pronephros in other species. The single nephron found there, however, does not differ significantly from the other nephrons of the head kidney. It is suggested, therefore, that the nephrons of the head kidney in this species are opisthonephric in origin.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740109
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  • 82
    Digitale Medien
    Digitale Medien
    A comparative immunocytochemical investigation of the crustacean hyperglycemic hormone (CHH) in the eyestalks of some decapod crustacea (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 161-168 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The eyestalk of the astacideans Orconects limosus, Nephrops norvegicus, and Homarus gammarus, and the palinuran Palinurus vulgaris, was examined with an antiserum raised against purified crustacean hyperglycemic hormone (CHH) of the astacidean species Astacus leptodactylus. A distinct immunopositive reaction occurs in a group of neurosecretory cells in the medulla terminalis ganglionic X-organ (MTGX), in the MTGX-sinus gland tractus, and in a considerable part of the sinus gland. The immunoreactive sites in the eyestalk of the investigated species correspond to the site of production, storage, and release of the CHH. Preliminary investigations with this antiserum also indicate that a positive immunoreaction can be obtained in the eyestalk of other decapod crustaceans, for example, of the brachyuran Macropipus puber and the caridean Palaemon serratus.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740205
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  • 83
    Digitale Medien
    Digitale Medien
    Structure of the shell from eggs of the tuatara, Sphenodon punctatus (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 197-205 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Shells from eggs of the tuatara (Sphenodon punctatus) are 0.2 mm thick and are composed of a layer of calcite and a multi-layered, fibrous shell membrane. Most of the calcareous layer is composed of roughly circular columns of crystalline material that extend deep into the shell membrane. The crystalline matrix of the columns is interwoven with fibers of the shell membrane except near the outer surface of the eggshell, where the calcareous material is more compact. Overlying the columns is a granular layer composed of blocks of crystalline material of random size, shape, and orientation. Disruption of this granular layer, perhaps through swelling of the eggs or as a result of environmental factors, gives the outer surface of the eggshell a coarse, weathered appearance. Removal of the calcareous material with a decalcifying agent shows that the outer surface of the shell membrane is composed of a meshwork of small fibers bound together by an amorphous matrix. No matrix was observed in inner layers of the shell membrane, and the fibers of these inner layers are arranged somewhat more regularly than the outer fibers. No structure comparable to the central cores of avian and certain chelonian eggs was observed in eggshells of the tuatara.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740208
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  • 84
    Digitale Medien
    Digitale Medien
    The leukocytic organ of the megascolecid earthworm, Amynthas diffringens (annelida, oligochaeta) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 174 (1982), S. 251-268 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Leukocytic organs of Amynthas diffringens are aggregations of leukocytes contained within a smooth muscle and stromal cell framework suspended in the coelom. Elongate processes of stromal cells subdivide each organ into numerous cell-filled compartments and are perforated by 130-nm pores that may permit the exchange of humoral substances between compartments, or between the organ and the surrounding coelomic fluid.We divide leukocytes within the organs into four morphotypes. Phagocytic leukocytes have many lysosomelike vesicles and may possess phagosomes. Mature types I, II, and III granulocytic leukocytes share certain features but are readily distinguished by cell shape and by the size, shape, and electron density of the cytoplasmic inclusions. Immature as well as mature phagocytes and granulocytes occur within these organs, suggesting that they are sites of leukocyte maturation and storage. Concentrations of leukocytes within the organs result in extensive cell to cell contact, especially within islets and tightly packed cords. Phagocytosis of cell debris occurs throughout the organs.Immature stages of the four morphotypes are difficult to distinguish even at high magnification, raising the possibility that they may originate from a common precursor. Our inability to observe mitoses or to detect lymphocytelike stem cells suggests that immature leukocytes migrate to the organs via coelomic fluid from as yet unidentified primary sites of production.
    Zusätzliches Material: 22 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051740302
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  • 85
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710101
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  • 86
    Digitale Medien
    Digitale Medien
    The cranial osteology and hyolaryngeal apparatus of Rhinophrynus dorsalis (Anura: Rhinophrynidae) with comparisons to recent pipid frogs (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 11-40 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The cranial osteology (including the hyolaryngeal apparatus) of Rhinophrynus dorsalis (Anura: Rhinophrynidae) is described from whole skeletons and serial cross sections. Some unique features of the extensively ossified skull include the enlarged and protracted olfactory region, for which the nasals form part of the septum nasi; the relatively short maxillaries and broad premaxillaries, and the immense quadratojugal; the extreme forward position of the quadrate; the lack of a firm articulation of the pterygoid and quadrate with the neurocranium and crista parotica; the quadrate lacking the distinct processes typical of other frogs; a single foramen for Nn. II-VII; a large, distinct operculum; and a bipartite hyale.Rhinophrynus shares other unusual cranial characteristics with the other pipoid frogs, Xenopus, Pipa, Hemipipa, and Hymenochirus. Among these features are the presence of a single frontoparietal in the adult, and the absence of parasphenoid alae, palatines, and mentomeckelian bones. Rhinophrynus differs from the pipids in the lack of a columella and a palatine process on the premaxilla, and in the possession of a quadratojugal, parahyoid bone, paired prevomers, olfactory eminence, massive quadrate that lacks distinguishable processes, a modified squamosal, and a bipartite hyale.Although the cranium of Rhinophrynus is distinctive, the evolutionary significance of its unusual features will remain obscure until comparable data are gathered from other closely related groups, the Discoglossoidea and the Pelobatoidea.
    Zusätzliches Material: 36 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710103
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  • 87
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710201
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  • 88
    Digitale Medien
    Digitale Medien
    Change of digastric muscle length in feeding rabbits (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 151-157 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: An experiment was undertaken to measure directly the changing length of a jaw muscle during feeding in four intact, unanesthetized New Zealand White rabbits. Metal markers were implanted to define the anterior and posterior ends of the single belly of the digastric muscle and fluroscopic images were recorded on videotape while the animals fed on pelleted chow and carrot. Graphs of muscle length versus incisor separation were obtained by making measurements of single frames of the videotape record. The graphs revealed that when pelleted chow was being chewed the length of the diagastric muscle changed by no more than 9% of its greatest length; during the latter part of the closing stroke it changed very little. Incising and chewing carrot caused the digastric muscle to change in length continuously throughout the chewing cycle; incising carrot resulted in a 13% change in the length of the digastric muscle. The velocity of shortening is slightly less than one muscle length per second.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710204
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  • 89
    Digitale Medien
    Digitale Medien
    Active supercontraction in rolling-up muscles of Glomeris marginata (myriapoda, diplopoda) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 75-82 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The lateroventral muscles of Glomeris marginata keep the animal rolled up and are able to develop and maintain great tension. Their fibers are not equipped with a particularly strong contractile apparatus but can super-contract. The sarcomere shortens its resting length by up 60% and in a typical supercontraction the thick filaments pass through the Z-line into adjacent sarcomeres. The Z-line structure changes according to the contraction state: It passes from a homogeneous, dense zig-zag line in decontracted fibers to a rarified, vaguely outlined Z-band in supercontracted fibers, in which it is possible to see actin and myosin filaments. The Z-line is thus involved in an active expanding process and is functionally very different from the fragmented and discontinuous Z-line of “classical” supercontracting muscles. The different meaning of the two cases of supercontraction is discussed.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720107
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  • 90
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720201
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  • 91
    Digitale Medien
    Digitale Medien
    The conjugation junction of Tetrahymena: Its structure and development (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 159-178 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The conjugation junction of Tetrahymena has been examined by thin sections, freeze fracture preparations, and by scanning electron microscopy. The junction is formed where the anterior tips of the pairing cells attach to one another. The structure is essentially a large disk composed of two face-to-face plasma membranes separated by a gap of extracellular space measuring about 50 nm. Rows of intramembrane particles are present at the boundary between the junction and ordinary cell cortex. These particles form a ring around the junction. Subjacent to each membrane is a thick mottled layer of material. Pores form in the junction at sites of membrane fusion. Though wider than long, these structures are actually bridges of cytoplasm that connect the conjugating cells. Pores fall into certain size and shape classes, indicating that membrane fusion is highly controlled in this system. At the level of the cytoplasmic bridge the submembrane material is compact and electron-dense. Changes in the structure of the epiplasmic layer have been monitored as the normal cortex is modified during tip transformation and through formation of the mature conjugation junction. Evidence is provided that the submembrane layer plays a significant role in the regulation of pore formation. This cytoskeletal structure may also limit the extent of membrane fusion, thus controlling the size of the cytoplasmic channels.
    Zusätzliches Material: 17 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720204
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  • 92
    Digitale Medien
    Digitale Medien
    Cerebellar afferents to paramedian lobule from the trigeminal complex in Tupaia glis: A horseradish peroxidase (HRP) study (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 209-222 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Projections from the trigeminal complex to paramedian lobule (PML) were studied in the tree shrew (Tupaia glis) by means of retrograde transport of horseradish peroxidase (HRP). Neurons which project to both dorsal and ventral folia of PML are located primarily in those areas of the trigeminal nuclear complex interpreted as nucleus interpolaris (Vi) and caudal areas of the nucleus oralis (Vo). The majority of HRP-labeled neurons lie in ventral and ventrolateral regions of Vi/Vo. No HRP-reactive cells are present in the principal (Vp), mesencephalic, or motor nuclei nor in nucleus caudalis or rostral portions of oralis. The majority of trigeminocerebellar (TC) cells are found in ipsilateral Vi; however, sparse numbers of labeled somata are present in this subnucleus on the contralateral side. Within Vi/Vo, small fusiform and medium- and large-sized multipolar neurons contain HRP-reaction product. Large multipolar cells are found primarily in ventrolateral portions of Vi/Vo, while medium and small neurons are scattered throughout the ventral half of the nucleus. Small-sized neurons are also present dorsally within Vi/Vo. Axons of labeled TC cells course laterally through the spinal trigeminal tract, enter medial aspects of the restiform body, and arch dorsally into the cerebellum.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720207
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  • 93
    Digitale Medien
    Digitale Medien
    Histology and histochemistry of the parotid and the principal and accessory submandibular glands of the little brown bat (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 271-285 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The parotid and the principal and accessory submandibular glands of the little brown bat, Myotis lucifugus (Vespertilionidae), were examined using light microscopy and staining methods for mucosubstances. The parotid gland is a compound tubuloacinar seromucous gland. Parotid gland secretory cells contain both neutral and nonsulfated acidic mucosubstances. The principal and accessory submandibular glands are compound tubuloacinar mucus-secreting glands. They contain somewhat atypical mucus-secreting demilunar cells that often appear to be interspersed between mucous tubule cells. The mucous tubule cells in both the principal and accessory submandibular glands contain sulfomucins. Demilunar cells of the principal submandibular gland contain moderate amounts of nonsulfated acidic mucosubstances, but the corresponding cells of the accessory submandibular gland contain considerable neutral mucosubstance with very little acid mucosubstance. Intercalated ducts composed of cuboidal or low columnar epithelial cells are present in all three glands. Striated ducts in all glands are composed of columnar cells whose apices bulge into the ductal lumina. Excretory ducts are composed of simple columnar epithelium, with occasional basal cells that suggest a possible pseudostratified nature. The cells of the excretory ducts also have bulging apices. All duct types contain apical cytoplasmic secretory material that is a periodic acid-Schiff positive, neutral mucosubstance. Ductal apical secretory material is more evident in intercalated and striated ducts than in excretory ducts.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720303
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  • 94
    Digitale Medien
    Digitale Medien
    Mechanisms of rapid morphogenetic movements in the metamorphosis of the bryozoan Bugula neritina (cheilostomata, cellularioidea). I. Attachment to the substratum (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 335-348 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The larval morphology, settlement behavior, and the rapid morphogenetic movements that occur during the first 60 sec of metamorphosis of the cellularioid cheilostome bryozoan Bugula neritina have been examined and analyzed by light and electron microscopy. The larva attaches to the substratum at the onset of metamorphosis by the eversion of the internal sac. At the same time, the coronal cilia reverse their direction of beat, spreading an adhesive secreted by the neck region of the everting sac over the metamorphosing larva. During attachment, the larva goes through several configurations that coincide with the sequential contraction and relaxation of certain larval muscles. Histological and ultrastructural evidence indicates that the neck and wall regions of the internal sac are everted by the contraction of the muscles in the equatorial plane of the larva at the same time that the roof region in pulled toward the larval equator by the contraction of the axial muscles. The subsequent relaxation of the axial muscles allows the roof region to be everted by the antagonistic force generated by the sustained contraction of the equatorial musculature. After the roof region attaches to the substratum, the apical disc is temporarily retracted by a second contraction of the axial muscles. The apical disc subsequently reextends as the axial muscles relax just before coronal involution. A comparison of the ontogenetic sequence of rapid morphogenetic movements in the metamorphoses of cheilostome and ctenostome bryozoans indicates that cellularioid cheilostomes have undergone peramorphosis in the aspect of development.
    Zusätzliches Material: 19 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720308
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  • 95
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730101
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  • 96
    Digitale Medien
    Digitale Medien
    Origin and formation of the royal fat body of the higher termite queens (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 17-28 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The formation of the royal fat body was studied by electron microscopy in three species of higher termites (Macrotermes bellicosus, Macrotermes subhyalinus, and Cubitermes fungifaber). The swarming alate imago has a storage fat body typical of most insects. In non-physogastric young queens, during the fasting period, the adipocytes deplete their reserves and then, along with the increased vitellogenesis, acquire protein-synthesizing structures (R.E.R.). During the development of physogastry they progressively specialize in protein synthesis and secretion and undergo many cell divisions. The cytological change is paralleled by a spatial reorganization of the fat body. Observations on the transformation of imaginal adipocytes into royal adipocytes show that the royal fat body is derived from the imaginal fat body and not from the tracheal cells as previously claimed.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730103
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  • 97
    Digitale Medien
    Digitale Medien
    Ultrastructure of the pineal gland of the eastern chipmunk (Tamias striatus) (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 173 (1982), S. 73-86 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The ultrastructure of the pineal gland of the wild-captured eastern chipmunk (Tamias striatus) was examined. A homogenous population of pinealocytes was the characteristic cellular element of the chipmunk pineal gland. Often, pinealocytes showed a folliclelike arrangement. Mitochondria, Golgi apparatus, granular endoplasmic reticulum, lysosomes, centrioles, dense-core vesicles, clear vesicles, glycogen particles, and microtubules were consistent components of the pinealocyte cytoplasm. The extraordinary ultrastructural feature of the chipmunk pinealocyte was the presence of extremely large numbers of “synaptic” ribbons. The number of “synaptic” ribbons in this species exceeded by a factor of five to 30 times that found in any species previously reported. In addition to pinealocytes, the pineal parenchyma contained glial cells (oligodendrocytes and fibrous astrocytes). Capillaries of the pineal gland of the chipmunk consisted of a fenestrated endothelium. Adrenergic nerve terminals were relatively sparse.
    Zusätzliches Material: 25 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051730107
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  • 98
    Digitale Medien
    Digitale Medien
    Fine structure of maxillary sensilla of larval Toxorhynchites brevipalpis (Diptera: Culicidae) with comments on the role of sensilla in behavior (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 171 (1982), S. 293-303 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Each maxilla of fourth instar Toxorhynchites brevipalpis bears nine sensilla: Four are located at the tip of the maxillary palp and five on the maxillary body. At the palp tip are three tapered pegs on bulbous bases (MS1, MS2, MS6) that are innervated by four, two, and two neurons, respectively, and probably function in chemoreception. Also at the palp tip is a sturdy, cuticular rod with a lumen (MS5) that opens distally to the exterior. The proximal end of the rod is closed by a cuticular base to which a single unbranched dendrite containing only a few microtubules is attached. The function of MS5 is enigmatic; possibilities include mechanoreception and detection of infrared radiation.On the maxillary body are two tapered pegs on a common bulbous base (GS1, GS2) that are each innervated by three neurons, and probably are chemosensory. Three setae also occur on the maxillary body. They arise from prominent sockets and are each innervated by a neuron terminating at the hair base as a tubular body, a characteristic of cuticular mechanosensilla.The maxillary sensilla are innervated by a total of 18 neurons: 14 are probably chemosensory, three mechanosensory, and one is of unknown function. These results, combined with those from a previous study on antennal sensilla (Jez and McIver, '80), indicate that the mechanosensitive neurons of the antennae and maxillae are a relatively small percentage of the total mechanosensilla on the entire larva. In contrast the chemosensitive neurons of the antennae and maxillae provide most of the information about the chemical environment of the larva.T. brevipalpis has three less than the maximum of seven maxillary palpal sensilla found in larval mosquitoes so far studied. This difference may reflect a lesser need for sensory information about the acceptability of potential food in predators compared to browsers and filter-feeders.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051710305
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  • 99
    Digitale Medien
    Digitale Medien
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982) 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720101
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    Digitale Medien
    Digitale Medien
    Integumentary appendages of chelonians (1982)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 172 (1982), S. 59-74 
    Details
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The head and neck of four families of turtles, the Chelydridae, Kinosternidae, Pelomedusidae, and Chelidae, possess a diverse assemblage of skin appendages. Appendages are termed barbels when they occur in the gular region and tubercles when they occur other places. The appendages consist of protrusions of the dermis and epidermis and are devoid of such specializations as taste buds or neuromasts. They lack skeletal tissue, muscle, or erectile tissue. Methylene blue and silver staining techniques reveal a high density of nerves. The occurrence and morphology of barbels and tubercles suggest that they function as mechanoreceptors. Skin appendages are most elaborate in carnivorous species and reach maximum development in two distantly related convergent species: Macroclemys temmincki (Chelydridae) and Chelus fimbriatus (Chelidae). Skin appendages also help provide camouflage and disruptive effects on the head. The increase in surface area produced by the appendages may be important in aquatic respiratory gas exchange in some species within the Kinosternidae.
    Zusätzliches Material: 30 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jmor.1051720106
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