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  • 1
    Electronic Resource
    Electronic Resource
    Morphogenesis and histogenesis of the connecting tubule in the rat kidney (1982)
    Springer
    Anatomy and embryology 165 (1982), S. 81-95 
    Details
    ISSN: 1432-0568
    Keywords: Kidney ; Connecting tubule ; Differentiation ; Growth and development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At the start of its morphogenesis the tubule of an S-shaped body always attaches to the terminal ampulla of the collecting duct. It remains attached there for some time while the terminal ampulla sprouts toward the renal capsule. The most distal part of the tubule that rises to the ampulla forms the connecting tubule, morphogenically the oldest segment of the tubulus nephroni. When younger S-shaped bodies join the same terminal ampulla, 2 to 3 connecting tubules are temporarily attached side by side to a single ampulla. Soon, however, the connecting tubule of the older nephron shifts its point of attachment away from the ampulla to the connecting tubule of the younger nephron. This process is repeated through successive nephron generations. Thus an arcade develops which at the close of morphogenesis includes the connecting tubules of the 3 to 4 oldest juxtamedullary and midcortical nephrons of the collecting duct and is always situated close to interlobular veins. The connecting tubules of the 2 youngest subcapsular nephrons are not incorporated into arcades, but join directly and permanently the collecting duct. — At the start of histogenesis, the undifferentiated tubule epithelium of the S-shaped body has a uniform structure over its entire length. At the junction of the connecting tubule and the terminal ampulla there is a cytologically sharp boundary between cuboidal, dark-stained connecting-tubule epithelium of the nephron and cylindrical, light-stained ampullary epithelium of the collecting duct. The epithelial differentiation begins in the oldest, juxtamedullary connecting tubules of an arcade and progresses upward to the terminal ampulla, so that immature connecting-tubule epithelium and immature ampullary epithelium are temporarily interposed between mature connecting-tubule epithelium and mature collecting-duct epithelium. The mature epithelium of the connecting tubule stains light, in which respect it behaves like the epithelium of the distal tubule. However, it also contains individual cells that are more strongly basophilic, stain dark and, though of nephrogenic origin, cannot be distinguished from the dark cells of the collecting duct by light microscopy. — Morphogenically and histogenically, the arcade-forming connecting tubules and the subcapsular connecting tubules arise from the nephrogenic blastema.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304585
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  • 2
    Electronic Resource
    Electronic Resource
    Histogenesis of the loop of Henle in the rat kidney (1982)
    Springer
    Anatomy and embryology 164 (1982), S. 315-330 
    Details
    ISSN: 1432-0568
    Keywords: Kidney ; Loop of Henle ; Differentiation ; Growth and development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelial differentiation of the loop of Henle was investigated in the kidneys of Wistar rats between embryonic day 15 and postnatal day 30. Three stages can be distinguished in the development of the loop of Henle: (1) the primitive loop, (2) the immature loop and (3) the mature loop. The primitive loop of Henle is composed of thick undifferentiated tubule epithelium and is divided into a strongly basophilic proximal tubule anlage that stains dark in the semithin section, and a weakly basophilic, light-staining distal tubule anlage. The two anlages are separated by a cytologically sharp boundary located in the descending limb just before the bend of the loop. The immature loop of Henle is present when differentiation of the tubule epithelium begins. The shorter initial portion of the proximal tubule anlage develops into proximal straight tubule epithelium with brush border, brush border enzymes and lysosomal enzymes, while the longer, more distal portion of the proximal tubule anlage develops into thin undifferentiated epithelium that is a transitory feature of the immature loop stage. The primitive epithelium of the distal tubule anlage develops into distal straight tubule epithelium. The cytologically sharp boundary of the thin undifferentiated epithelium and distal tubule epithelium is located just before the bend of the loop. The loop of Henle matures as the thin undifferentiated epithelium in the medullary ray and outer stripe of the outer medulla becomes transformed into proximal straight tubule epithelium. At the point where this descending differentiation ends, the borderline of the inner and outer stripe of the outer medulla arises. The thin undifferentiated epithelium in the inner stripe and the inner medulla differentiates into the thin epithelium of the descending limb of Henle's loop. In the bend and ascending limb of long loops, the thick distal tubule epithelium is trans-formed by an ascending autophagous process into the thin epithelium of the ascending limb of Henle. The termination of this process marks the borderline between the inner and outer medulla. The thin descending and thin ascending limb of Henle arise from 2 different anlages; between them lies the histogenetic boundary of the proximal and distal renal tubule.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315754
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  • 3
    Electronic Resource
    Electronic Resource
    Gradient of adaptability in four different motor systems performing the same learned motor task in cats (2003)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 18 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The ability of four different brainstem motoneuron pools to perform a newly acquired motor task was studied in alert cats. A classical conditioning of eyelid responses was carried out in (i) unoperated animals, and in animals with (ii) transection, 180° rotation, and re-suture of the zygomatic facial nerve branch, (iii) a crossed anastomosis of the buccal to the zygomatic facial nerve branch and (iv) a hypoglossal–facial nerve anastomosis. Animals were conditioned with a delay paradigm using a tone (350 ms, 600 Hz, 90 dB) as conditioned stimulus, followed 250 ms later by an air puff (100 ms, 3 kg/cm2) as unconditioned stimulus. Animals with zygomatic nerve rotation performed conditioned responses (CRs) at control rate, with significantly larger amplitude, area and velocity, but a de-synchronized oscillatory pattern. Animals with buccal–zygomatic anastomosis acquired CRs at control rate, but these CRs had significantly smaller amplitude than those of controls and a de-synchronized pattern. Animals with a hypoglossal–facial anastomosis were unable to perform CRs. The trigeminal hyper-reflexia triggered by the axotomy was probably the origin of the large CRs after zygomatic nerve rotation. Trigeminal hyper-reflexia could also contribute to generation of the small CRs recorded after buccal–zygomatic anastomosis. Although trigeminal hyper-reflexia was also present following hypoglossal–facial anastomosis, hypoglossal motoneurons did not reach their firing threshold to perform CRs. In accordance with the embryonic origin of involved motoneurons, animals with buccal–zygomatic and hypoglossal–facial anastomoses moved the ipsilateral eyelid synchronously to mouth-related activities. It is suggested that there is a gradient of adaptability in motoneuron pools forced to perform new motor tasks through foreign muscles, which depends on their embryological origins and functional properties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2003.03019.x
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  • 4
    Electronic Resource
    Electronic Resource
    Contralateral trigeminal nerve lesion reduces polyneuronal muscle innervation after facial nerve repair in rats (1999)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 11 (1999), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Functional recovery after facial nerve surgery is poor. Axotomized motoneurons (hyperexcitable upon intracellular current injections, but unable to discharge upon afferent stimulation) outgrow supernumerary branches which are misrouted towards improper muscles. We hypothesized that alterations in the trigeminal input to axotomized electrophysiologically silent facial motoneurons might improve specificity of reinnervation. To test this we compared, in the rat, behavioural, electrophysiological, and morphological parameters after transection and suture of the buccal facial nerve (buccal–buccal anastomosis, BBA) with those after BBA plus excision of the ipsi- or contralateral infraorbital nerve (ION). After BBA, the mystacial vibrissae dropped and remained motionless until 18–21 days post operation (days PO). After BBA plus ipsilateral ION excision, there was no recovery of vibrissae whisking at all. Following BBA plus contralateral ION excision, full restoration of whisking occurred at 7–10 days PO. Electromyography of whiskerpad muscles showed normal waveform and amplitude was also most rapidly restored after BBA plus contralateral ION excision. Neuron counts after retrograde tracing showed that the intact buccal nerve contained axons of the superior (91%) and inferior (9%) buccolabial nerves. After BBA, the superior nerve comprised 56%, the inferior 21%, and 23% of the motoneurons projected within both nerves. After BBA plus ipsilateral ION excision, misdirection worsened and values changed to 48, 39 and 13%, respectively. After BBA plus contralateral ION excision, portions improved to 69, 23 and 8%. We conclude that, by reducing the redundant axon branching, lesion of contralateral ION provides the best conditions for recovery of vibrissae rhythmical whisking after reconstructive surgery on the facial nerve.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.1999.00545.x
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  • 5
    Electronic Resource
    Electronic Resource
    Multimodal early onset stimulation combined with enriched environment is associated with reduced CNS lesion volume and enhanced reversal of neuromotor dysfunction after traumatic brain injury in rats (2005)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 21 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: This study was designed to determine whether exposure to multimodal early onset stimulation (MEOS) combined with environmental enrichment (EE) after traumatic brain injury (TBI) would improve neurological recovery and to elucidate its morphological correlates. Male Sprague–Dawley rats were subjected to lateral fluid percussion (LFP) brain injury or to sham operation. After LFP, one-third of the animals (injured and sham) were placed under conditions of standard housing (SH), one-third were kept in EE only, and one-third received EE + MEOS. Assessment of neuromotor function 24 h post-injury using a standardized composite neuroscore test revealed an identical pattern of neurological impairment in all animals subjected to LFP. Neuromotor dysfunction in SH animals remained on a similar level throughout the experiment, while improvements were noted in both other groups 7 days post-injury (dpi). On 15 dpi, reversal of neuromotor dysfunction was significantly better in EE + MEOS animals vs. SH- and EE-only groups. In parallel, the comparison of lesion volume in EE + MEOS- vs. EE-only vs. SH rats revealed that animals exposed to EE + MEOS had consistently the lowest values (mm3, mean ± SD; n = 6 rats in each group) as measured in serial brain sections immunostained for neuron-specific enolase (5.2 ± 3.4 ≤ 5.5 ± 4.1 〈 9.5 ± 1.9), caspase 3-active/C3A (5.9 ± 4.0 ≤ 6.4 ± 3.9 〈 10.3 ± 1.8) and glial fibrillary acidic protein (6.0 ± 3.4 ≤ 6.5 ± 4.3 〈 10.7 ± 1.2). This first report on the effect of EE + MEOS treatment strongly indicates that the combined exposure reduces CNS scar formation and reverses neuromotor deficits after TBI in rats.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.04070.x
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  • 6
    Electronic Resource
    Electronic Resource
    Factors limiting motor recovery after facial nerve transection in the rat: combined structural and functional analyses (2005)
    Oxford, UK : Blackwell Science Ltd
    European journal of neuroscience 21 (2005), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It is believed that a major reason for the poor functional recovery after peripheral nerve lesion is collateral branching and regrowth of axons to incorrect muscles. Using a facial nerve injury protocol in rats, we previously identified a novel and clinically feasible approach to combat axonal misguidance – the application of neutralizing antibodies against neurotrophic factors to the injured nerve. Here, we investigated whether reduced collateral branching at the lesion site leads to better functional recovery. Treatment of rats with antibodies against nerve growth factor, brain-derived neurotrophic factor, fibroblast growth factor, insulin-like neurotrophic factor I, ciliary neurotrophic factor or glial cell line-derived neurotrophic factor increased the precision of reinnervation, as evaluated by multiple retrograde labelling of motoneurons, more than two-fold as compared with control animals. However, biometric analysis of vibrissae movements did not show positive effects on functional recovery, suggesting that polyneuronal reinnervation – rather than collateral branching – may be the critical limiting factor. In support of this hypothesis, we found that motor end-plates with morphological signs of multiple innervation were much more frequent in reinnervated muscles of rats that did not recover after injury (51% of all end-plates) than in animals with good functional performance (10%). Because polyneuronal innervation of muscle fibres is activity-dependent and can be manipulated, the present findings raise hopes that clinically feasible and effective therapies could be soon designed and tested.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.2005.03877.x
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  • 7
    Electronic Resource
    Electronic Resource
    Mitochondria in fine afferent nerve fibres of the knee joint in the cat: a quantitative electron-microscopical examination (1994)
    Springer
    Cell & tissue research 275 (1994), S. 493-501 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Mitochondria – Free nerve ending – Nociceptors – Knee joint – Aδ-fibre – C-fibre – Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The distribution of mitochondria, their content and concentration (expressed as the ratio of the mean volume of mitochondria and the surface of the sensory axon) were determined in group-III and -IV nerve fibres innervating the knee joint capsule in the cat. Mitochondria mainly accumulated in axonal swellings (“beads”) and end bulbs of the terminal branches. Between single nerve fibres, marked differences in the content and the concentration of mitochondria were obtained in proximal portions (inside of the perineurium) and in distal portions (unmyelinated sensory endings). In group-III nerve fibres, the mitochondrial concentration ranged from 0.005 to 0.030 μm3/μm2(proximal portion) and from 0.016 to 0.080 μm3/μm2(distal portion). In unmyelinated group-IV nerve fibres, the values also showed a broad variation ranging from 0.001 to 0.011 μm3/μm2(proximal portion) and from 0.003 to 0.019 μm3/μm2(distal portion). The wide range of mitochondrial concentrations may reflect different energy consumption during receptive processes: nerve fibres with a low mechanical threshold and a high probability of excitatory events may be rich in mitochondria, whereas fibres with a high mechanical threshold and a low probability of excitatory events may be poor in mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318818
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  • 8
    Electronic Resource
    Electronic Resource
    Mitochondria in fine afferent nerve fibres of the knee joint in the cat: a quantitative electron-microscopical examination (1994)
    Springer
    Cell & tissue research 275 (1994), S. 493-501 
    Details
    ISSN: 1432-0878
    Keywords: Mitochondria ; Free nerve ending ; Nociceptors ; Knee joint ; Aδ-fibre ; C-fibre ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of mitochondria, their content and concentration (expressed as the ratio of the mean volume of mitochondria and the surface of the sensory axon) were determined in group-III and-IV nerve fibres innervating the knee joint capsule in the cat. Mitochondria mainly accumulated in axonal swellings (“beads”) and end bulbs of the terminal branches. Between single nerve fibres, marked differences in the content and the concentration of mitochondria were obtained in proximal portions (inside of the perineurium) and in distal portions (unmyelinated sensory endings). In group-III nerve fibres, the mitochondrial concentration ranged from 0.005 to 0.030 μm3/μm2 (proximal portion) and from 0.016 to 0.080 μm3/μm2 (distal portion). In unmyelinated group-IV nerve fibres, the values also showed a broad variation ranging from 0.001 to 0.011 μm3/μm2 (proximal portion) and from 0.003 to 0.019 μm3/μm2 (distal portion). The wide range of mitochondrial concentrations may reflect different energy consumption during receptive processes: nerve fibres with a low mechanical threshold and a high probability of excitatory events may be rich in mitochondria, whereas fibres with a high mechanical threshold and a low probability of excitatory events may be poor in mitochondria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318818
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  • 9
    Electronic Resource
    Electronic Resource
    Quantitative image analysis of the chromatolysis in rat facial and hypoglossal motoneurons following axotomy with and without reinnervation (1996)
    Springer
    Cell & tissue research 286 (1996), S. 537-541 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Chromatolysis ; Regeneration ; Degeneration ; Image analysis ; Hypoglossal nerve ; Facial nerve ; Rat (Wistar ; Hsd Cpb: WU)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Image analysis was used to quantify the time course of chromatolysis in regenerating and degenerating motoneurons. Following facial-facial, hypoglossal-hypoglossal nerve suture, or resection of facial and hypoglossal nerves with postoperative survival times of 4 h to 112 days, the texture of the Nissl substance of facial and hypoglossal motoneurons was analyzed on both sides of the brainstem in paraffin serial sections with a VIDASplus image analyzer. In this quantitative study of 149 Wistar rats, alterations of the Nissl substance were measured that were statistically significant but not yet visible to the human eye. Chromatolysis started significantly as early as 8 h and was not fully reversed 112 days after any of the types of axotomy. The reaction was more intense and longer lasting following axotomy without reinnervation than with reinnervation. Thus, chromatolysis starts much faster and lasts far longer than was previously known. The quantified chromatolysis is much stronger after permanent target deprivation than during complete regeneration of motoneurons but is reversible in both cases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050723
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  • 10
    Electronic Resource
    Electronic Resource
    Invaginated apical vacuoles in the cells of the proximal convoluted tubule in the rat kidney (1984)
    Springer
    Cell & tissue research 235 (1984), S. 463-466 
    Details
    ISSN: 1432-0878
    Keywords: Endocytosis ; Kidney (rat) ; Proximal tubule ; Apical vacuoles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Following perfusion fixation of the rat kidney with glutaraldehyde the proximal tubule cells display small apical vacuoles, large apical vacuoles, and apical vacuoles in which a part of the limiting membrane is invaginated into the vacuole. These invaginated apical vacuoles occur more frequently in proximal convoluted tubules than in proximal straight tubules. One tubular cell may contain apical vacuoles of different sizes and stages of invagination, ranging from larger vacuoles with a wide lumen and a small area of invaginated membrane to smaller elements with no apparent lumen and a large area of invaginated membrane. Invaginated apical vacuoles lie either singly in the cytoplasm or close to the membranes of other apical vacuoles, but never in contact with the cell membrane or the membranes of lysosomes, endoplasmic reticulum, Golgi apparatus, mitochondria and peroxisomes. These findings suggest that the invaginated apical vacuoles are not fixation artifacts, but rather develop in living state in cells of the proximal tubule from spherical endocytotic elements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217875
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