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  • 1985-1989  (835)
  • 1975-1979
  • 1988  (835)
  • Organic Chemistry  (765)
  • Ultrastructure
  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructural and cytochemical examination of the nuclear crystalloid inclusions of Olea europaea L. mesophyll cells (1988)
    Springer
    Trees 2 (1988), S. 261-266 
    Details
    ISSN: 1432-2285
    Keywords: Nuclear crystalloid inclusions ; Olea europaea ; Cytochemistry ; Ultrastructure ; Glycoprotein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The nuclei of mesophyll cells of olive trees contain numerous sizeable crystalloid inclusions. Cytochemical examination using epoxy resin-embedded, semithin-sectioned tissue indicated the presence of proteins and oligoor polysaccharides in these inclusions. Their electron microscopical analysis revealed a crystalline substructure consisting of intersected subunits of high order. The spacing of the lattice fibrils and the angles of intersection were determined and used to establish a model of the unit cell of crystallization. It is suggested that the nuclear crystalloids of olive trees consist of glycoprotein molecules. They differ from the intranuclear crystalloids observed in other species predominantly in the high density of their subunit arrangement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00202381
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  • 2
    Electronic Resource
    Electronic Resource
    Collagenous colitis: Histologic, morphometric, immunohistochemical and ultrastructural studies. Report of 21 cases (1988)
    Springer
    Virchows Archiv 413 (1988), S. 287-296 
    Details
    ISSN: 1432-2307
    Keywords: Collagenous colitis ; Myofibroblasts ; Myoid cells ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined 129 colonic biopsies from 21 patients with collagenous colitis, most of whom presented with diarrhoea. Morphometric measurements gave a mean thickness of the subepithelial collagen deposit of 19.5 µ ± 5.1. The trapped fusiform and/or stellate cells within the deposits were identified immunohistochemically as myoid cells, being positive with antibody against smooth muscle cell alpha-actin. Ultrastructurally, these cells have all the characteristic features of myofibroblasts. Similar cells are also present along the crypts, where they were formerly referred to as pericryptal fibroblasts. Although there is still much debate as to the pathogenesis of this condition, we would like to suggest that collagenous colitis is a disease of pericryptal myofibroblasts. During their migration and maturation into the subepithelial region they may synthesize an excess of collagen, under some yet unknown or undefined stimulus/stimuli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00783020
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  • 3
    Electronic Resource
    Electronic Resource
    Pre-fertilization degeneration of both synergids in Brassica campestris ovules (1988)
    Springer
    Sexual plant reproduction 1 (1988), S. 208-216 
    Details
    ISSN: 1432-2145
    Keywords: Megagametophyte ; Synergids ; Brassica campestris ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In Brassica campestris, both synergids of the ovule degenerate before the arrival of the pollen tube. Synergid degeneration does not depend on pollination. At the non-degenerated stage, the synergids are completely filled with a complexly organized cytoplasm containing numerous mitochondria with many cristae, a large number of dictyosomes with many associated vesicles, and a very extensive rough endoplasmic reticulum. The degenerative changes that occur in the cytoplasm of the synergids are characterized by a loss of visibility of the membranes of the endoplasmic reticulum and the simultaneous formation of dense deposits on the surrounding membranes of the mitochondria. Locally, the plasma membranes of the synergids disappear, and some ground plasma of the synergids penetrates into the space between the plasma membranes of the egg cell and the central cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189154
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of chronic diabetes mellitus on the electrical and contractile activities,45Ca2+ transport, fatty acid profiles and ultrastructure of isolated rat ventricular myocytes (1988)
    Springer
    Pflügers Archiv 411 (1988), S. 564-572 
    Details
    ISSN: 1432-2013
    Keywords: Isolated cardiac myocytes ; Electrical activity ; Contraction ; Fatty acids ; Ultrastructure ; Diabetes mellitus, experimental ; Streptozotocin ; Electrophysiology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of chronic experimental diabetes on electrophysiological properties, contractile behavior,45Ca2+ transport, fatty acid profiles and ultrastructural characteristics were studied in enzymatically dissociated ventricular myocytes. Diabetes was induced in rats by streptozotocin administration and animals were killed 8–10 weeks later. Myocytes from diabetic rats exhibited electrical behavior similar to that of myocytes from control rats, but their contractile properties were altered. Their sensitivity of the twitch contractions to various positive and negative inotropic agents (isoproterenol, norepinephrine, phenylephrine, acetylcholine, ouabain and veratridine) was greatly diminished. However, a part of the contractile response (the tonic, sustained contractions) were increased in the diabetic myocytes, indicating that the changes are not caused by a decreased sensitivity of myofilaments. Furthermore, the diabetic myocytes exhibited also significant decrease in total Ca2+ content. The fatty acid profile in the diabetic group was changed mainly in that there were slightly elevated levels of docosahexaenoic acid and diminished levels of palmitic acid. The ultrastructure of the diabetic myocytes was affected only slightly. These investigations offer for the first time a comprehensive picture of changes related to diabetic cardiomyopathy as they occur at the level of cardiomyocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00582379
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  • 5
    Electronic Resource
    Electronic Resource
    Electron microscope localisation of insulin-like immunoreactivity of conventionally processed human insulinomas (1988)
    Springer
    Virchows Archiv 412 (1988), S. 443-450 
    Details
    ISSN: 1432-2307
    Keywords: Insulin ; Insulinomas ; Ultrastructure ; Immunogold technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Localisation of insulin-like immunoreactivity has been studied using the immunogold staining procedure on thin sections of 6 human insulinomas, conventionally processed for electron microscopy. The labelling was restricted to the secretory granules. Depending on their morphology, these either resembled B-cell granules of human adult pancreas or belonged to the atypical (non-diagnostic) group. Within the former group, those with a crystalloid core or an amorphous dense or moderately dense core were strongly immunoreactive, whereas others, filled with a pale material, were poorly labelled. Most granules of this type were stored together within the heavily granulated cells of 3 insulinomas, presenting the classical features of clinical and biological behaviour and a typical light microscopic staining pattern. In contrast, the non-diagnostic granules, characterized by their smaller size, a very dense core and a thin halo, were mainly found within the poorly granulated cells making up the other tumours, and showed a very uneven labelling. Strongly labelled granules were found in one insulinoma that also belonged to the classical type; these were stored together with a few diagnostic granules within the same cells. Only poorly labelled atypical granules were present in two cases revealing a number of unusual features; these included moderate elevation of insulinaemia, uncertain tumour histology, as well as weak immunostaining for insulin/proinsulin and variable argyrophilia of the tumour in paraffin sections. These findings suggest that human insulinomas differ not only in storage capacity but also in their degree of granule maturation. This may involve some deficiency of either the prohormone conversion or the subsequent processing of the cleavage products.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00750578
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  • 6
    Electronic Resource
    Electronic Resource
    Cat scratch disease (1988)
    Springer
    Virchows Archiv 412 (1988), S. 563-572 
    Details
    ISSN: 1432-2307
    Keywords: Cat scratch disease ; Epidemiology ; Ultrastructure ; Bacterial morphology ; Warthin-Starry stain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aetiological agent of cat scratch disease (CSD) has been unknown for more than 30 years. Recently, a micro-organism clearly shown with Warthin-Starry silver (W-S) stain was found and thought to be a possible cause of the disease. In this study, 32 cases of regional lymphadenopathy histologically compatible with CSD and 20 contrasting cases of lymphadenopathy were examined retrospectively with W-S stain. W-S positive pleomorphic organisms were clearly demonstrated in 20 of the 32 suspected cases of CSD, but in none of the other cases. The onset of disease in these 20 cases with W-S positive organisms occurred between July and January. This seasonal variation in the onset of disease was highly significant (P〈0.005) and was not due to a single epidemic. Moreover, some characteristic morphological features of the organism were found by electron microscopic observations. Ultrastructurally, the organism was a bacterium showing a chain-like arrangement, septal formation, branching and clubbed ends.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844292
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  • 7
    Electronic Resource
    Electronic Resource
    Ultrastructural and immunohistochemical characteristics of lipid-rich carcinoma of the breast (1988)
    Springer
    Virchows Archiv 413 (1988), S. 381-385 
    Details
    ISSN: 1432-2307
    Keywords: Lipid rich carcinoma ; Breast ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Five cases of lipid-rich carcinomas of the breast were investigated ultrastructurally and immunohistochemically for alpha-lactalbumin (ALA), lactoferrin (Lfr) and human milk fat globule membrane antigen (HMFG-2). Staining for ALA and Lfr showed intensive reaction on nearly all of the tumour cells whereas immunoreaction for HMFG-2 revealed positivity in single cells. All tumours were negative for steroid receptor content. Ultrastructurally the tumour cells showed numerous intracytoplasmic non-membrane bound lipid droplets which were often found within autophagocytic vacuoles. Neither rough endoplasmic reticulum nor Golgi complexes showed any sign of lipid synthesis. Extrusion of lipid droplets and extracellular lipid deposition was not observed. In conclusion, our findings do not justify the consideration of lipid-rich carcinoma of the breast as a clearly defined group of tumours with specific secretory activity. Therefore, the term lipid-rich carcinoma should be used in preference to lipid-secreting, unless there is evidence of active lipid secretion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00716986
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructural study of chromatolytic neurons in an adult-onset sporadic case of amyotrophic lateral sclerosis (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 523-528 
    Details
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Chromatolysis ; Ultrastructure ; Motor neuron disease ; Hyaline intraneuronal inclusions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural features of chromatolytic neurons observed in a sporadic case with amyotrophic lateral sclerosis (ALS) are reported. A 70-year-old woman died of weakness and atrophy of the four limbs, bulbar and facial muscles, and hyperreflexia, of 3 1/2 years' duration. Neuronal loss was marked in the anterior horn of the spinal cord, with degeneration of the pyramidal tracts. Most of the remaining neurons showed chromatolysis. Some of the chromatolytic neurons contained faintly eosinophilic inclusions with a halo. Few spheroids were observed. Hypoglossal nuclei, nucleus ambiguus, motor nuclei of N. VII and N.V were well populated, but contained several chromatolytic neurons. Ultrastructurally, the chromatolytic neurons contained aggregates of fibrils thicker than the 10-nm neurofilaments. These fibrils were arranged randomly, and were closely associated with granular materials as well as rough endoplasmic reticulum. Neurofilamentous accumulations reported to be common in sporadic ALS were rare in this case. No Bunina body was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687142
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  • 9
    Electronic Resource
    Electronic Resource
    A new type of cytoplasmic inclusion in human choroid plexus (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 11-16 
    Details
    ISSN: 1432-0533
    Keywords: Choroid plexus ; Cytoplasmic inclusion ; Histochemistry ; Ultrastructure ; Frequency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We described a new type of cytoplasmic inclusion in the choroidal epithelial cells of humans. The inclusions usually appeared as brown, round or elongated bodies with or without an inner core, ranging in size from 1.3 to 7.0 μm. Histochemically, they contained polysaccharides, proteins and compound lipids. Ultrastructurally, they were composed of finely granular and filamentous materials, which are densely packed in the inner core and less dense in the outer zone. The frequency study of the inclusions in 197 autopsied patients revealed that their occurrence had no correlation with the age or the disease category. It is concluded that the inclusions are a nonspecific, but peculiar, change of the choroidal epithelial cells, probably representing the morphological expression of a physiological or pathological alteration of the cellular metabolism at the single-cell level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687675
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  • 10
    Electronic Resource
    Electronic Resource
    Creutzfeldt-Jakob disease with intranuclear vacuolar inclusions: a biopsy case of negative light microscopic findings and successful animal transmission (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 422-426 
    Details
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jakob disease ; Slow virus ; Pathology ; Ultrastructure ; Intranuclear vacuolar inclusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a 53-year-old man with a progressive mental deterioration and myoclonic jerks, brain biopsy failed to show any significant light microscopical findings. Electron microscopy revealed membranebound vacuolar inclusions in many neuronal nuclei as the only prominent finding. Hamsters intracerebrally inoculated with the biopsy material demonstrated typical spongiform changes in the gray structures of the brain when sacrificed on the 309th and 332nd days post inoculation, characteristic of experimental Creutzfeldt-Jakob disease (CJD). These intranuclear vacuolar inclusions, originally reported in experimental Creutzfeldt-Jakob disease in this laboratory, may be a valuable electron microscopic feature in some CJD cases and may play an important role in supporting the diagnosis of CJD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686980
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  • 11
    Electronic Resource
    Electronic Resource
    Ultrastructural abnormalities of in vitro fertilization of in vitro matured bovine oocytes (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 47-52 
    Details
    ISSN: 1432-0568
    Keywords: Ultrastructure ; In vitro fertilization ; Bovine ; Ova ; Cortical granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes collected from cows at an abattoir by aspiration from small (1–6 mm) antral follicles were matured and inseminated in vitro. At different time intervals after insemination the ova were processed for transmission electron microscopy. Up to and including 6 h after insemination all ova were unfertilized, and their cortical granules were more or less clustered. At 6 h acrosome reaction of spermatozoa was observed on the surface of the zona pellucida. At 8 h the first fertilized ovum appeared and the first fully developed spherical pronucleus was observed, at 20 h the first apposition of pronuclei was seen, and at 40 h divisions were ongoing or completed. More than one third of the fertilized ova showed polyspermic penetration of the zona pellucida, and in most of these ova different developmental stages of supernumerary pronucleus formation were observed in the ooplasm. Abnormal cortical granule release was seen in approximately half of the fertilized ova, and it was more frequent in ova with polyspermic as opposed to monospermic penetration of the zona pellucida.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305013
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  • 12
    Electronic Resource
    Electronic Resource
    Scanning electron microscopy of in vitro fertilization in cattle (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 41-46 
    Details
    ISSN: 1432-0568
    Keywords: In vitro fertilization ; Bovine ; Ultrastructure ; Ova ; Spermatozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cumulus-oocyte complexes were collected from cows at an abattoir by aspiration from small (1–6 mm) follicles. The complexes were matured in vitro for 28 h. Subsequently, the cumulus cells and the zona pellucida were removed by enzyme treatment in a proportion of the complexes (zona-free ova). Both cumulus-enclosed and zonafree ova were inseminated in vitro and processed for scanning electron microscopy after different periods of culture. In the cumulus-enclosed ova the number of spermatozoa attached to and penetrating into the cumulus investment increased with increasing culture time. Practically all spermatozoa displayed intact acrosomes. In the zona-free ova clusters of spermatozoa attached to the ovum surface, and at 5 h a proportion of the spermatozoa had undergone the acrosome reaction, and their internalization into the ooplasma was initiated. The acrosome reaction was characterized by an increasing fenestration of the membrane coverings of the acrosomal region of the sperm head. During the sperm head internalization, where the ovum microvilli appeared to contact especially the equatorial segment and the postacrosomal region, the sperm head gradually disappeared from the ovum surface, and the microvilli at the site of internalization became more bulbous. Simultaneous abstriction of the second polar body was seen in some ova.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00305012
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  • 13
    Electronic Resource
    Electronic Resource
    Pathogenesis of pili annulati (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 308-318 
    Details
    ISSN: 1432-069X
    Keywords: Pili annulati ; Ultrastructure ; DACM staining ; Hair cortex ; Protein metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Plucked scalp hairs and hair roots of pili annulati were examined to understand their pathogenesis. Stereoscopic examinations of hairs in transmitted light and/or reflected light and light microscopic surveys of the cross-sections of hairs confirmed that the cortical empty spaces appeared to be responsible to the unique dotted shiny appearance of the hairs seen by the unaided eyes under a refracted light. By transmission electron microscope, small vacuoles and dense bodies were observed in the cytoplasm of the differentiating cortical cells; subsequently, with increasing number of tonofilaments, an uneven distribution of free ribosomes occurred and abnormal spaces containing fine granular substances were formed in the cytoplasm of the cortical cells. Occasionally, extremely large cortical trichohyaline granules were found. In the keratinized hair, irregular empty spaces were present in the cortex of the abnormal hair segments. Histochemically, the keratinized cortex of the affected hairs always had more residual SH groups than the controls. Pili annulati may be a disorder of protein metabolism involving a partial dysfunction of cytoplasmic ribosomes, resulting in a lack of cortical keratin formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00440605
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  • 14
    Electronic Resource
    Electronic Resource
    Esthesioneuroblastoma: a nasal catecholamine-producing tumor of neural crest origin (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 522-527 
    Details
    ISSN: 1432-0533
    Keywords: Esthesioneuroblastoma ; Tyrosine hydroxylase (TH) ; Immunohistochemistry ; Ultrastructure ; Catecholamine-producing tumor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An esthesioneuroblastoma in a 16-year-old male was studied ultrastructurally and immunohistochemically, using antiserum against tyrosine hydroxylase (TH), a rate-limiting enzyme in the catecholamine-synthesizing pathway. Tumor cells were fairly uniform in appearance, showing scantly cosinophilic cytoplasm and round to oval hyperchromatic nuclei, and were arranged in nests and cords of various sizes. Ultrastructurally, individual tumor cells had well-developed cell organelles including polyribosomes, microtubules, intermediate filaments, centrioles, Golgi apparatus and mitochondria. Secretory-like granules were occasionally found, predominantly in the cell processes. Immunohistochemically, many tumor cells were shown to be immunoreactive for TH. This finding strongly suggested that the present tumor was capable of producing catecholamines and that it might be derived from certain sympathetic neuronal cell nests in the superior nasal cavity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686393
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  • 15
    Electronic Resource
    Electronic Resource
    Ultrastructural pathology in emetine-induced myopathy (1988)
    Springer
    Acta neuropathologica 75 (1988), S. 577-582 
    Details
    ISSN: 1432-0533
    Keywords: Cytoplasmic bodies ; Emetine ; Myopathy ; Sarcomeric lesions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Progressive myopathy developed in two women who consumed ipecac syrup containing emetine hydrochloride to induce vomiting as part of their anorexia nervosa. Muscle biopsy specimens were characterized by severe disruption of the sarcomeres. The ultrastructural spectrum extended from “Z-band streaming” to the formation of cytoplasmic bodies and also comprised abnormalities of the sarcotubular system, thus suggesting that muscle weakness may be related to both sarcomeric and sarcotubular lesions in this self-inflicted myopathy. It is tempting to suggest that muscle weakness may be correlated with or based on the pathology in sarcomeres and the sarcotubular system. As the myopathy is clinically reversible upon discontinuation of ipecac consumption the morphological findings should also be potentially reversible. Experimentally induced emetine myopathy may, thus, serve as a useful model to study morphological dynamics of sarcomeric lesions, which may be observed separately or simultaneously in a variety of spontaneously occurring human neuromuscular disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00686202
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  • 16
    Electronic Resource
    Electronic Resource
    Cytomembranous inclusions in the brain of a patient with the acquired immunodeficiency syndrome (1988)
    Springer
    Acta neuropathologica 76 (1988), S. 101-106 
    Details
    ISSN: 1432-0533
    Keywords: AIDS ; Confronting cylindrical cisterns ; Cytomembranous inclusions ; Tubuloreticular inclusions ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies of cells and tissues in the acquired immunodeficiency syndrome (AIDS) have revealed two distinct cytomembranous inclusions referred to as “tubuloreticular inclusions” (TRI) and “confronting cylindrical cisterns” (CCC). TRI are found most often in leukocytes and endothelial cells in conditions with elevated levels of alpha-interferon, such as viral infections, autoimmune diseases and certain neoplasms. On the other hand, CCC are detected almost exclusively in mononuclear inflammatory cells and are limited to a few conditions, of which AIDS is the most common. CCC have been proposed as an ultrastructural marker for human immunodeficiency virus (HIV) infection. We describe CCC in mononuclear inflammatory cells in the brain of a patient with AIDS. Finding CCC in brain tissue with no other specific feature such as multinucleated giant cells, nevertheless, should alert the neuropathologist to the possibility that the patient might have AIDS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00687686
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  • 17
    Electronic Resource
    Electronic Resource
    Effects of oxygen concentration on embryonic development in rats: a light and electron microscopic study using whole-embryo culture techniques (1988)
    Springer
    Anatomy and embryology 178 (1988), S. 337-343 
    Details
    ISSN: 1432-0568
    Keywords: Hyperoxia ; Hypoxia ; Teratogenesis ; Rat embryo ; Whole-embryo culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By using a whole-embryo culture technique (New 1978), the effects of oxygen concentration (5%, 20% and 95% oxygen) on embryonic development in the rat were investigated by light and electron microscopy. The best embryonic development occurred when the 9.5-day-old embryos were cultured for 24 h with 5% oxygen, and the 10.5-day-old embryos with 20% oxygen (optimum oxygen concentration). When the 9.5- and 10.5-day-old embryos were cultured for 24 h with too little or too much oxygen, retardation of the embryonic growth and abnormal development was observed. Using light microscopy, numerous degenerating cells, exhibiting granular deposits in the cytoplasm, were seen, but the distribution of the degenerating cells was quite different between the two groups. With electron microscopy, the most striking feature of the degenerating cells in the embryos cultured with too little oxygen, was the extreme swelling of the mitochondria without any morphological alterations of the nucleus or the other cell organelles. On the other hand, the characteristic feature of the degenerating cells in the embryos exposed to too much oxygen, was the formation of phagolysosomes in the cytoplasm. Morphological alterations of the nucleus or mitochondria were not evident. In the present study, the possible teratogenic mechanism of too much or too little oxygen in the whole-embryo culture of the rat embryo is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00698664
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  • 18
    Electronic Resource
    Electronic Resource
    Ultrastructural identification of Merkel cells around the mouth of the newborn marsupial (1988)
    Springer
    Anatomy and embryology 177 (1988), S. 403-408 
    Details
    ISSN: 1432-0568
    Keywords: Marsupial ; Newborn ; Ultrastructure ; Merkel cells ; Mechanoreceptor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the epidermal cells surrounding the mouth of three newborn marsupial species, the Northern native cat Dasyurus hallucatus, the brush tail possum Trichosurus vulpecula and the Northern brown bandicoot Isoodon macrourus were examined. The presence of Merkel cells, highly sensitive touch receptors, would suggest that the sense of touch aids the relatively underdeveloped newborn marsupial to move from the urinogenital sinus to the pouch and to locate the teat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304737
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  • 19
    Electronic Resource
    Electronic Resource
    An ultrastructural and morphometric analysis of the Sertoli cell during the spermatogenic cycle of the rat (1988)
    Springer
    Anatomy and embryology 179 (1988), S. 191-203 
    Details
    ISSN: 1432-0568
    Keywords: Sertoli cell ; Spermatogenic cycle ; Ultrastructure ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of Sertoli cells from selected stages of the spermatogenic cycle was assessed by morphometric analysis which showed significant changes in the morphological features of Sertoli cell cytoplasm at the commencement of the cycle (stage II) compared to the middle (stages VII-VIII) and the completion of the cycle (stages IX-XIV). Total volume and surface area of organelles (rough and smooth endoplasmic reticulum (ER), lysosomes, mitochondria and Golgi) exhibited stage-dependent and cyclic variations as did the total surface area of Sertoli cell plasma membrane. Polarization of cytoplasmic organelles to basal or columnar regions of the Sertoli cell, exhibited particularly by the Golgi, rough ER and lysosomes also showed marked cyclic fluctuations during the spermatogenic cycle. Rough and smooth ER exhibited the most dramatic stage-dependent changes in total volume and surface area the former being respectively largest and smallest in stages VII-VIII and XIII-XIV, the latter organelle presenting the reverse pattern in these two groups of stages. Similar stage-dependent alterations of lysosome volume and surface area were also noted, being maximal during stages XIII-XIV-II and reaching a nadir at stage VIII. Although the functional role of most Sertoli cell organelles and inclusions remain largely unknown, the present study suggests that the cyclic and stage-dependent variations in ultrastructure probably reflect major changes in Sertoli cell function necessary for the regulation of the spermatogenic cycle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00304701
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  • 20
    Electronic Resource
    Electronic Resource
    Treatment of infantile phytanic acid storage disease: clinical, biochemical and ultrastructural findings in two children treated for 2 years (1988)
    Springer
    European journal of pediatrics 147 (1988), S. 133-142 
    Details
    ISSN: 1432-1076
    Keywords: Infantile Refsum disease ; Phytanic acid ; Dietary treatment ; Peroxisomes ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two patients with infantile phytanic acid storage disease (infantile Refsum disease), one of whom showed the presence of morphologically normal peroxisomes in a liver biopsy, were treated with a low phytanic acid diet for more than 2 years and the effects of treatment on certain clinical, biochemical and ultrastructural parameters were examined. Both patients showed evidence of either an improvement or stabilisation in their clinical condition. Plasma phytanic acid levels decreased to near normal values in approximately 6 weeks after the introduction of the diet; plasma pipecolic acid also declined markedly but the decrease was not so rapid and its level remained abnormal. C26∶C22 fatty acid ratios decreased very slowly and even after 2 years the values remained grossly abnormal. Despite the marked reduction of phytanic acid in the liver, there was an increase in the C26∶C22 fatty acid ratios and this appeared to be paralleled by an increase in inclusion bodies. Our data suggest that some patients with the infantile form of Refsum disease may show some clinical benefit from dietary management and this is reflected biochemically by decreases in the plasma levels of phytanic acid and pipecolic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00442210
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  • 21
    Electronic Resource
    Electronic Resource
    Cadmium induced changes in cell organelles: an ultrastructural study using cadmium sensitive and resistant muntjac fibroblast cell lines (1988)
    Springer
    Archives of toxicology 62 (1988), S. 133-145 
    Details
    ISSN: 1432-0738
    Keywords: Cadmium ; Ultrastructure ; In vitro ; Nucleus ; Cytoplasm ; Muntjac
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A detailed electron microscopy study of cadmium sensitive and resistant muntjac fibroblast cell lines has identified a wide range of intracellular damage following exposure to cadmium. Damaged organelles included cell membrane, mitochondria, Golgi cisternae and tubular network, chromatin, nucleoli, microfilaments and ribosomes. Although cell membrane damage was generally the earliest indication of adverse cadmium action, particularly with continuous cadmium exposures, cells could tolerate extensive membrane loss. Mitochondrial distortion and some damage to Golgi was also tolerated. The turning point at which cadmium became lethal was generally marked by a cascade of events which included damage to both nuclear and cytoplasmic components. These results for fibroblasts are discussed and compared with damage reported in other types of cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00570131
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  • 22
    Electronic Resource
    Electronic Resource
    Ultrastructural observations in port wine stains (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 338-345 
    Details
    ISSN: 1432-069X
    Keywords: Port wine stain ; Endothelium ; Basement membrane ; Collagen ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cause for the progressive vascular dilatation in port wine stains remains unclear. We compared the histology and ultrastructure of lesional and adjacent normal skin in paired biopsy specimens of 12 and 8 patients, respectively (age range, 6 to 53 years). In semithin sections, the lesions of all patients showed ectatic vessels and a fine-fibrous or hyaline thickening of the walls of postcapillary venules, as well as in some instances a loosening of the surrounding connective tissue. Ultrastructurally, the wall material consisted predominantly of peripheral deposits of amorphous material interspersed with collagen fibrils (diameter, 35±4 nm); occasionally the number of basal laminae in the inner part was also increased. Cross-banded filamentous aggregates with a periodicity of 95 nm were observed in and around the walls. The endothelium of many patients displayed fenestrations and/or small gaps. Various kinds of alterations of the intervascular connective tissue were found. We conclude that structural alterations of the vascular and later also of the intervascular connective tissue are related to the dilatation of the vessels. These findings are in agreement with the immunopathologically demonstrated increase of basement membrane components in the same biopsy specimens, but are interpreted as secondary phenomena. Endothelial stability and permeability may also be affected.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00426611
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  • 23
    Electronic Resource
    Electronic Resource
    Structural alterations of collagen fibrils in the reactive type of elastosis perforans serpiginosa (1988)
    Springer
    Archives of dermatological research 280 (1988), S. 319-322 
    Details
    ISSN: 1432-069X
    Keywords: Elastosis perforans serpiginosa ; Collagen fibrils ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00440606
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  • 24
    Electronic Resource
    Electronic Resource
    Serotonin-immunoreactivity in the monkey lateral geniculate nucleus (1988)
    Springer
    Experimental brain research 69 (1988), S. 662-666 
    Details
    ISSN: 1432-1106
    Keywords: Serotonin ; Lateral geniculate nucleus ; Monkeys ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Serotonin-immunoreactivity in the monkey lateral geniculate nucleus appears as a plexus of fine, beaded fibers decreasing in density from magnocellular to parvocellular laminae. Ultrastructurally, these fibers show strictures and dilations, and are filled with dense round particles as well as granular material attached to outer mitochondrial membranes and microtubules. Most of the profiles followed in serial sections lack morphologically defined synapses. The few synapses observed are asymmetric, some with subjunctional dense bodies. This appearance suggests a possible excitatory effect mainly on interneurons which in turn would inhibit principal cells. Serotonin released non-synaptically may block the delivery of transmitters from retinal terminals and/or the receptors for such transmitters, thereby exerting a modulatory depressing action on principal cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247318
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  • 25
    Electronic Resource
    Electronic Resource
    Effect of AF64A on the cholinergic systems of the retina and optic tectum of goldfish (1988)
    Springer
    Experimental brain research 70 (1988), S. 455-462 
    Details
    ISSN: 1432-1106
    Keywords: Cholinergic toxin ; Retina ; Optic tectum ; ChAT ; Ultrastructure ; Goldfish
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary AF64A, a presumed selective cholinergic neurotoxin has been used to study the effect on cholinergic systems of the goldfish retina and optic tectum. Toxin injection in the vitreum and in the optic tectum caused a selective decrease of choline acetyltransferase activity in both areas, while no significant decrease of glutamate decarboxylase and D-3H aspartate uptake were observed at different times after the injections. The effect was particularly dramatic in the retina of long term-injected animals, where choline acetyltransferase dropped to practically zero level. The ultrastructural analysis showed selective degeneration of some neurons in the amacrine and ganglion cell layer of the retina as well as of synaptic terminals and neuronal cell bodies in the optic tectum. The results favour a selective cholinotoxicity of AF64A in fish nerve tissue at doses substantially higher than those found to have additional unselective effects in mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247593
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  • 26
    Electronic Resource
    Electronic Resource
    Reinnervation of dopamine neurons by regenerating serotonin axons in the rat medial zona incerta (1988)
    Springer
    Experimental brain research 72 (1988), S. 473-480 
    Details
    ISSN: 1432-1106
    Keywords: Serotonin ; Tyrosine hydroxylase ; Zona incerta ; Regeneration ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cellular relationships between serotonin (5-HT) axons and tyrosine hydroxylase (TH)-containing neurons were examined by combined (3H)5-HT uptake radioautography and TH immunocytochemistry in the medial zona incerta (ZI) of adult rats, 7 and 50 days after an intracerebral injection of 5,7-Dihydroxytryptamine (5,7-DHT). Seven days post-lesion, only rare, scattered (3H)5-HT-labeled axon terminals were apparent in the zone of the medial ZI accessible to intraventricularly injected (3H)5-HT. In contrast, in sham-injected animals (3H)5-HT-labeled varicosities were numerous and often observed adjacent to TH-immunoreactive perikarya and dendrites. Fifty days post 5,7-DHT injection, the density of (3H)5-HT-labeled terminals approximated that seen in sham-treated animals. At the ultrastructural level, these regenerated 5-HT axons were similar in size, shape and content to those observed in sham-operated rats. Also, as in sham, some of the (3H)5-HT-labeled axons were directly apposed to TH-immunopositive labeled profiles. The latter included large dendritic shafts and dendritic spines, but only rare perikarya. In both sham- and 5,7-DHT-treated animals a few of the contacts between (3H)5-HT-labeled and TH-immunoreactive profiles exhibited an asymmetric synaptic differentiation. These results indicate that 5-HT fibers in the medial ZI, following regeneration, can reestablish normal relationships and even synapses with a given population of chemically identified cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00250592
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  • 27
    Electronic Resource
    Electronic Resource
    Estrogen-induced alterations in synaptic morphology in the midbrain central gray (1988)
    Springer
    Experimental brain research 69 (1988), S. 522-530 
    Details
    ISSN: 1432-1106
    Keywords: Estrogen ; Synapse ; Ultrastructure ; Midbrain central gray ; Lordosis behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Axons of ventromedial hypothalamic (VMH) neurons have been previously shown to terminate in the midbrain central gray (MCG) (Chung et al. 1984, 1986). Since VMH synapses in this region may be involved in the mediation of estrogen-induced lordosis behavior, we examined the effect of estrogen on the morphology of synapses in the MCG. Ovariectomized adult female rats were given daily subcutaneous injections of estradiol benzoate (10 μg) or the vehicle control and after 20 days of injection, only the estrogen-treated rats showed the lordosis response. A quantitative analysis of MCG tissue from these animals demonstrates morphological changes in various synaptic parameters with estrogen treatment including: 1) an increase in the mean number of dense-cored vesicles and an increase in the number of terminals containing densecored vesicles, 2) an increase in the length of postsynaptic densities (PSDs), 3) an increase in the number of PSDs showing perforations, 4) an increase in the number of synapses, and 5) an increase in the number of synapses with positive synaptic curvature. No alterations in the number of subjunctional bodies were observed. The dense-cored vesicles may contain an estrogen-induced trophic factor which may function in maintaining the integrity of postsynaptic processes and cells in the MCG with which VMN endings contact (Chung et al. submitted) and/or which induces morphological changes in postsynaptic structures which facilitate the effects of estrogen on lordosis behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00247306
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  • 28
    Electronic Resource
    Electronic Resource
    Ultrastructural characterisation of macrophages (type A cells) in the synovial lining (1988)
    Springer
    Rheumatology international 8 (1988), S. 171-176 
    Details
    ISSN: 1437-160X
    Keywords: Ultrastructure ; Synovium ; Macrophages ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural localisation of class II and macrophage antigens has been sought in the intimal layer of the human synovium. The cells described as type A in early morphological studies are shown to express both class II antigens and two markers of the macrophage/monocyte lineage of cells, OKM1 and MAB 24. The morphological type B cells were found to express none of these antigens. The findings are consistent with the idea that the synovial lining comprises two cell types, bone-marrow derived macrophages and mesenchymal fibroblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00270456
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  • 29
    Electronic Resource
    Electronic Resource
    The basement membrane and associated structures in the murine endolymphatic sac (1988)
    Springer
    European archives of oto-rhino-laryngology and head & neck 245 (1988), S. 266-272 
    Details
    ISSN: 1434-4726
    Keywords: Murine endolymphatic sac ; Basement membrane ; Fluid transport ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of the basement membrane of the murine endolymphatic sac was studied under various experimental conditions in labyrinthectomized and ethacrynic acid-treated animals and was compared with normal anatomy. The basement membrane was clearly visualized after staining with ruthenium red or dialyzed iron. The basement membrane of the murine sac consists of two different layers: the lamina rara and the lamina densa. It demarcates the border between the epithelial cells and the subepithelial connective tissue. Our findings suggest that the basement membrane acts as a physical support to the epithelium in the endolymphatic sac. The basement membrane also shows a dynamic capacity to form a new basement membrane, with the result that the lateral intercellular space between contiguous epithelial cells may be integrated with the subepithelial space. This system is believed to act as a macromolecular and bulk water transport system. In the subepithelial space, collagen, reticular and elastic fibrils are found having a close relationship to the basement membrane. The elastic fibres are presumed to play a role in the pressure-regulating mechanism in the endolymphatic sac.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00464628
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  • 30
    Electronic Resource
    Electronic Resource
    The effect of low pH and aluminum on the olfactory organ of rainbow trout, Salmo gairdneri (1988)
    Springer
    Environmental biology of fishes 22 (1988), S. 69-77 
    Details
    ISSN: 1573-5133
    Keywords: Acid ; Metals ; Ultrastructure ; Olfaction ; Electrical response ; Pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The effects of acid ((H2SO4) and aluminum AIKSO4 in acidified water on rainbow trout, Salmo gairdneri, olfactory organ were examined using scanning electron microscopy and electrophysiology. Exposure to pH 4.7 resulted in an increase in the number of mucus droplets over parts of the olfactory epithelium, primarily along the ridges of the secondary folds. The addition of aluminum (5.0, 9.5, 20.0 µmol · 1−1) at pH 4.7 resulted in loss of receptor cell cilia, irregularly shaped olfactory knobs, clumped microvilli and swellings on microridge cells. Electrical responses recorded from the olfactory nerve in response to the amino acid L-serine were similar to controls in fish exposed to acidified water. When fish were exposed to acidified water and aluminum the response was depressed. These morphological and electrophysiological changes could be used to indicate metal-induced stress in fish from natural ecosystems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000544
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  • 31
    Electronic Resource
    Electronic Resource
    Effects of intralipid and hydrocortisone upon human fetal lung cell cultures (1988)
    Springer
    Research in experimental medicine 188 (1988), S. 411-423 
    Details
    ISSN: 1433-8580
    Keywords: Human fetal lung cell cultures ; Lamellar bodies ; Pneumocytes type II ; Intralipid ; Hydrocortisone ; Ultrastructure ; Morphometric analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Organotypic cell culture systems of human fetal lungs of 15, 18, and 26 weeks' gestational age were treated with Intralipid, a phosphatidylcholine-containing lipid mixture, and with hydrocortisone of varying concentrations. The lamellar bodies found in the pneumocytes type II were ultrastructurally identified. Their amount was quantitated by point-counting, a morphometrical method. Intralipid had a stimulating effect upon the surfactant production depending on the concentration admitted. This effect was quantitatively compared to the known effect of hydrocortisone. Intralipid at a concentration of 10−2% produced a significant increase of the relative volume of lamellar bodies (P = 0.05) at a gestational age of 18 weeks. This effect is comparable to hydrocortisone treatment at a concentration of 10−1% (P = 0.05) and 10−3% (P = 0.01). At a gestational age of 26 weeks, Intralipid at a concentration of 10−1% (P = 0.01) stimulated lamellar body production. Hydrocortisone had a similar effect at a concentration of 10−1% (P = 0.01). Intralipid does not pass the placenta-barrier and is locally applied by amniocentesis. Therefore, complications to the maternal organism and probably to the fetuses are negligible. The application of Intralipid represents an alternative method to accelerate antenatal surfactant production and to improve the rate of survival of preterm infants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01851999
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  • 32
    Electronic Resource
    Electronic Resource
    Observations of soybean root meristematic cells in response to heat shock (1988)
    Springer
    Protoplasma 144 (1988), S. 1-9 
    Details
    ISSN: 1615-6102
    Keywords: Heat shock ; Soybean root ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Soybean seedlings (Glycine max) were incubated in narrow temperature regimes to study the effects of heat shock on cell structures. The incubation temperatures used were as follows: 1. 28 °C (2h); 2. 40 °C (2h); 3. 45 °C (2h); 4. 40 °C (2h)→45 °C (2h); 5. 47. 5 °C (10 min); 6. 40 °C (2h)→47. 5 °C (10 min). Both optical and electron micrographs were taken of the different tissues of root meristems as they responded to heat shock. Cells of roots heated to 45 °C (2h) or 47.5 °C (10 min) with lethal treatment showed drastic heat injuries:e.g., membrane damage, coagulated plasmolysis, protoplasmic contraction, and leakage of cell content. Nucleolar segregation occurred in cells treated at both lethal and supraoptimal temperatures. Seedlings preincubated at 40 °C (2 h) became thermo-tolerant to lethal temperature treatment of 45 °C (2 h) or 47.5 °C (10 min), by protecting the plasmalemma, mitochondria, plastids and nuclei from heat damage. Without preincubation, however, these structures were destroyed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320274
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  • 33
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    Electronic Resource
    Preliminary observations on the formation of the male germ unit in pollen tubes ofCyphomandra betacea sendt. (1988)
    Springer
    Protoplasma 147 (1988), S. 55-63 
    Details
    ISSN: 1615-6102
    Keywords: Generative cell ; Sperm cell ; Treetomato ; Ultrastructure ; Vegetative nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The structure of the generative cell and its association with the vegetative nucleus in the pollen tube ofCyphomandra betacea Sendt. were observed with the electron microscope. The generative cell, bounded by its own plasma membrane and the inner plasma membrane of the vegetative cell, possesses the cytoplasmic extension which lies within the embayments of a vegetative nucleus. The generative cell contains the normal complement of organelles and, especially, microtubules which cluster into several groups adjacent to the plasma membrane, oriented along the longitudinal axis of the cell. In the pollen tube reaching the lower end of the style aftersemivivo pollination, both of the sperm cells are elongated and polyribosomes and microtubules are the outstanding feature in the cytoplasm. The two sperm cells are connected by a common transverse cell wall, while cytoplasmic channels exist in both the periplasm of the two sperm cells and the transverse wall. The leading sperm cell (Svn) is closely associated with the vegetative nucleus. Thus the present study demonstrates the existence of the male germ unit in the pollen tube ofC. betacea. The possible cytoplasmic continuity between the sperm cells and between the gametes and vegetative cell is considered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01403877
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    Electronic Resource
    A novel oxygen induced reduction of α, β-unsaturated carbonyl compounds by benzeneselenol (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 115-117 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A novel oxygen induced reduction of α,β-unsaturated carbonyl compounds is discovered. The reduction of the carbon-carbon double bond of α,β-unsaturated carbonyl compounds by benzeneselenol was caused by an introduction of molecular oxygen into the reaction system. This reduction is likely to proceed via a radical chain pathway involving an SH2 type reaction between a phenylseleno radical and a 1,2-adduct of benzeneselenol to the carbonyl group of the α,β-unsaturated carbonyl compound to give an allylic radical which absracts a hydrogen atom from benzeneselenol to form the reduction product.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010207
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  • 35
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    Electronic Resource
    ESR studies of photochemical reaction of 2-methyl-3-acetylquinoxaline N,N′-dioxide(MAQO) (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 191-195 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photochemical reaction of MAQO with various aromatic amines were studied by ESR. The results show that nitroxide radicals are stable productrs of the photooxidation of both diphenylamines and phenylamines. The photolyzed phenothiazine does not yield nitroxide as the final product, instead it gives the neutral radical as the stable final product.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010403
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    Syntheses, spectroscopic characterization and electronic structure of cyclopropenylidene ligated platinum complexes (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 333-349 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: New series of platinum complexes of cyclopropenylidenes of the types of PtX2(CP)2 and trans-PtX(PBu3)2(CP) have been synthesized, where CP is di-t-butylcyclopropenylidene (BCP) or bis(diisopropylamino)cyclopropenylidene (ACP). The 13C-NMR chemical shifts, and 13C-195Pt coupling constants (1JPtC) for the complexes are discussed in comparison with those values derived from closely related series of compounds, trans-PtCl(PR3)2L; L — —CH3, —C6H5 and —C≡CBu-t. An excellent linear relationship through the origin was obtained between 1JPtC and the formal ‘s’ % character of the carbon directly bonded to Pt for the series trans-PtCl(PR3)2L in which the Pt—C bond is regarded as a pure σ-linkage, whereas 1JPtC deviates largely from this relationship when pπ—dπ bonding interaction possibly exists in the Pt—C bond. The NMR data suggest the strong nmr trans-influence of the cyclopropenylidenes and that in the Pt—CP bond the σ-interaction is appreciable but the π-interaction is negligible.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010604
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    Electronic Resource
    Electronic Resource
    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010301
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  • 38
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    Photocyclization of N-Alkyl-N-(3-aryl-3-butenyl) ureas. Hydrogen transfer via charge transfer exciplexes in alkene photochemistry (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 123-131 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photolysis of N-alkyl-N-(3-aryl-3-butenyl) ureas (1) in acetonitrile gave cyclization products, 3-aryl-3-methyl-pyrrolidines, in good yields, whereas irradiation of 1 in methanol afforded methanol adducts as well as the cyclization products. Both the reactions are singlet reactions, and the cyclization is presumed to proceed via 1,6-hydrogen transfer from exciplexes with charge transfer character.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010302
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  • 39
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    The Effect of hydrophobic-lipophilic interactions on chemical reactivity. 12. Mechanistic investigations of NaCMA-catalyzed hydrolysis of esters (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 143-151 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependence of the catalytic efficiencies of sodium carboxymethylamylose (NaCMA) for the hydrolysis of N-lauryl-3-acetoxypyridinium iodide (1) and p-nitrophenyl dodecanoate (3) on its degree of substitution (D. S. = 0·00, 0·12, 0·18, 0·24, 0·29 and 0·35) and on the pH values of the solutions (pH = 7·32, 7·80, 8·10 and 9·30) have been studied. At fixed D. S. values, the observed hydrolysis rates of 1 and 3 increase with increasing concentrations of NaCMA and follow saturation kinetics. At fixed concentration of NaCMA, the rates increase with decreasing D. S. values until they reach maxima at D. S. = 0·00. Furthermore, at any D. S. value the catalytic efficiency increases with increasing pH values of the solutions. All these results indicate that the hydroxyl groups are actually the principal catalyzing groups.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010304
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  • 40
    Electronic Resource
    Electronic Resource
    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010401
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  • 41
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    Participation of beta carbon-silicon bonds in the development of positive charge in five-membered rings (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 169-178 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The development of positive charge β to silicon in a saturated five-membered ring has been studied in the cis- and trans-2-(trimethylsilyl)cyclopentyl trifluoroacetates. The cis substrate solvolyzes in 97% trifluoroethanol at 25° C about 5 times faster than the analogous six-membered ring, after correction for differences in ring strain. The trans substrate solvolyzes about 360 times more slowly than the analogous six-membered ring. These changes are in agreement with a hyperconjugative mechanism for interaction between the silyl group and the developing positive charge. The expected cosine-squared dependence of hyperconjugation on the Si—C—C—X dihedral angle suggests that the cis dihedral angle is reduced somewhat from the 60° in the six-membered ring, and the trans dihedral angle is reduced substantially from the 180° in the six-membered ring.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010307
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    Acidities of radical cations derived from arylacetonitriles (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 209-223 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The equilibrium acidities of phenylacetonitrile, and 20 of its m- and p-substituted derivatives have been measured in Me2SO solution. Their pKa′s plot linearly with those of the corresponding anilines. Combination of the pKa′s of these acids with their oxidation potentials, Eox(HA), and those of their conjugate bases, Eox(A-), provide an estimate of the acidities of the corresponding radical cations. The pKHA+ values for ArCH2CN+., where Ar is Ph, 1- and 2-naphthyl, and 9-anthryl, are -32, -18·5, -17·5, and -11, respectively, compared to 21·9, 20·85, 20·65, and 19·8 for the corresponding ArCH2CN acids. Acidities of PhCH(Me)CN+., Ph2CHCN+., 9-CN-FlH+., and 9-CN-XnH+. are -33, -35, -25, and -27, respectively, compared to 23·0, 17·5, 8·3, and 13·6 for the corresponding acids from which they were derived. The homolytic bond dissociation energies (BDEs) for the benzylic C—H bonds in these arylacetonitriles, estimated by combining pKHA with Eox(A-), fall in the range of 69 kcal/mol for 9-CN-XnH to 82 kcal/mol for PhCH2CN. For GC6H4CH2CN+. radical cations the acidities are decreased, relative to G=H, when G is an electron donor substituent and increased when G is an acceptor. The BDEs of the benzylic C—H bonds in GC6H4CH2CN are weakened by up to 4 kcal/mol by para donors and strengthened by up to 1·2 kcal/mol by m- or p-acceptors. The significance of these changes in BDEs with regard to the use of σ. scales and the ΔAOP method for estimating substituent effects on radical stabilities is discussed.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010405
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    Oxygen-atom transfer chemistry of α-AZO hydroperoxides: Effect of competitive intramolecular hydrogen bonding and α-methyl substitution (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 259-265 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 1-(Phenylazo)-1-(2-pyridyl)ethyl hydroperoxide, 1, 1-(phenylazo)-1-(2-furyl)ethyl hydroperoxide, 2, phenylazo(2-furyl)methyl hydroperoxide, 3, 1-(phenylazo)-1-(4-anisyl)ethyl hydroperoxide, 4, were synthesized in moderate yield by autoxidation of the phenylhydrazones in benzene. The ionic oxidation of benzyl methyl sulfide in benzene by 1-4 yielded the sulfoxide and the metastable α-azo hydroxides in essentially quantitative yield. The reaction was of the first order in α-azo hydroperoxide and sulfide, respectively. The relative reactivity series found was: 1(1.0) 〈4(1.4) 〈 phenylazo(4-anisyl)methyl hydroperoxide 5 (2·9) 〈2 (3·8) 〈 3 (9·6). α-Methyl substitution was found to slow the rate of oxygen-atom trasfer by a factor of 2 to 2.5. The low relative reactivity of 1 was opposite that expected based on electronic effects. Competitive intramolecular hydrogen bonding of the hydroperoxy proton to the pyridyl nitrogen in 1 accounted for the observed result.
    Additional Material: 2 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010503
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    Extrusions of dibromocarbene under neutral conditions (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 281-285 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The thermal and photochemical decompositions of 5 have been studied. Both reactions lead to CBr2 transfer in good to high yields. With the 2-pentenes as substrates, CBr2 transfer is stereospecific in the classical singlet carbene manner.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010506
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  • 45
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    Homocub-1(9)-ene trapped (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 305-308 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Decomposition of the tosylhydrazone salts formed from cubyl carboxaldehyde and homocubanone, potential precursors of cubylcarbene (5) and homocubanylidene (6), leads in each case to products derived from 6. It is suggested that homocub-1(9)-ene (7) is the active ingredient in the formation of 6 from both precursors. The hydrazones formed from N-aziridylamines are useful photochemical sources of 6, and presumably other carbenes. Flash vacuum pyrolysis of the tosyl hydrazone salts and hydrazones at 600°C leads to indene.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010509
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  • 46
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    Novel reactions of sterically protected fused 1,2,3-selenadiazole. A new aspect of reactivity of organoselenium intermediates (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 317-332 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Light- and heat-induced decompositions and reactions with nucleophiles of 6,6,8,8-tetramethyl-2-selena-3,4-diaza-7-oxabicyclo[3.3.0]octa- 1(5),3-diene have been studied. In contrast with the conversion to the cyclopentyne derivative (9), selenium containing intermediates (6a, 6b, and 7) were efficiently trapped using several reagents to give various kinds of organoselenium compounds. Of particular note is the isolation of a stable selenirane derivative (16) obtained by the cycloaddition of the photochemically generated selenirene intermediate (7) with furan. The character and reactivity of the intermediates are also discussed.
    Additional Material: 3 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010603
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    The solvatochromic equation and insight into chemical reactivity (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 359-362 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Reaction rates for solvolysis of a mustard analogue are accurately correlated by the solvatochromic equation without inclusion of a nucleophilicity term, and thus the equation is shown to reveal mechanistically significant information.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010606
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010501
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    Concerning the weakness of intramolecular general acid catalysis in the hydrolysis of vinyl ethers. o-carboxy-α-methoxy-β,β-dimethylstyrene (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 247-257 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rate of hydrolysis of the aromatic vinyl ether o-carboxy-α-methoxy-β,β-dimethylstyrene was found to be accelerated 25-fold by ionization of its carboxylic acid group, but the effective molarity which may be calculated if all of this rate acceleration is ascribed to intramolecular general acid catalysis is only EM = 1 · 1 m. This is similar to the small effective molarities found before for intramolecular catalysis by carboxylic acid groups of aliphatic vinyl ethers, which shows that, unlike the situation in other intramolecular reactions, e.g. ketone enolization, the extra rigidity of aromatic over aliphatic systems does not improve the efficiency of intramolecular catalysis in vinyl ether hydrolysis.It is suggested that this behaviour is the result of reduced conjugation between the vinyl ether group and the aromatic ring in the transition state of the vinyl ether hydrolysis reaction, which retards the rate and offsets any improvement effected by increased rigidity of the aromatic system.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010502
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  • 50
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    Synthesis of optically active 2,2′-diselenocyanato-1,1′-binaphthyl and its molecular structure. Hypervalent nature of divalent selenium atom in crystal state (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 179-184 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: 2,2′-Diselenocyanato-1,1′-binaphthyl(1), the first selenium-containing binaphthyl derivative, has been synthesized in optically active form the corresponding diamine by diazotization followed by the reaction with potassium selenocyanate. Its molecular structure is determined by X-ray diffraction method. It is revealed that selenium atoms have hypervalent penta-coordination in the crystal.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010308
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    Ab initio Mo calculations on the rearrangements of 7-oxa-2-bicyclo[2.2.1]heptyl cations. The facile migration of acyl group in wagner-meerwein rearrangements (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 287-298 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Ab initio STO-3G and 6-31G minimized geometries of 5-oxo- (9), 6-oxo-7-oxabicyclo[2.2.1]hept-2-yl cation (12) and 7-oxabicyclo[2.2.1]hept-2-yl cation (15) were obtained. The energy barriers for their Wagner-Meerwein rearrangements to the more stable 5-oxo- (11), 6-oxo-3-oxabicyclo[2.2.1]hept-2-yl (13) and 3-oxabicyclo[2.2.1]hept-2-yl (17) cations, respectively, have been evaluated and compared with those calculated for the rearrangement of the 5-oxo (18) and 6-oxobicyclo[2.2.1]hept-2-yl cations (20). In agreement with experimental data, the ‘true migratory aptitude’ of an acyl group is higher than that of β-oxoalkyl group in competitive Wagner-Meerwein rearrangments that are ‘energetically unbiased’. The ease of the acyl group 1,2-shift toward an electron-deficient center is related to the electron-donating ability of the carbonyl group due to favorable n(CO) ↔ σ σ ↔ p(C+) hyperconjugative interaction.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010507
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    Free radical chain reactions of ate complexes. Electron transfer processes 42 (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 299-303 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Iodide ion promotes the free radical reaction of isopropylmercury idide with bromotrichloromethane to yield isopropyl bromide with rate enhancement in the order of 104. The reaction involves electron transfer from i-PrHgI2- to the trichloromethyl radical in a long kinetic chain process. Iodide ion also promotes the free radical chain conjugate addition of tert-butylmercury chloride to α,β-unsaturated ketones, esters, phosphonate esters and sulfones. Competitive reactivity studies indicate that lithium di-tert-butylcuprates or tri-tert-butylzincates react with 2-cycloalkenones by a mechanism involving attack by tert-butyl radicals. No evidence for radical attack is observed for the corresponding n-butyl ate complexes of copper or zinc.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010508
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    Effect of cosolvent additives on relative rates of photooxidation on semiconductor surfaces (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 103-114 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The effect of solvent additives on the course of TiO2 photocatalyzed oxygenation of α-methylstyrene has been studied. While the addition of small amounts of nonhalogenated alcohols to TiO2 powders suspended in acetonitrile was found to decrease the rate of photooxygenation, added halogenated alcohols increase the rate of reaction. In addition, the solvent additives affect the observed product distribution.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010206
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  • 54
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    Oxygen induced reduction: Reaction of benzeneselenol with aromatic aldehydes in the presence of oxygen (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 119-121 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Reduction of aromatic aldehydes by benzeneselenol is found to be promoted by molecular oxygen to give corresponding alcohols in good yields. No reduction took place without oxygen.A free radical process involving SH2 reaction at the selenium atom is proposed where the phenylseleno radical attacks the selenium atom of selenohemiacetal, the adduct of benzeneselenol to aldehyde, to give the ketyl radical which then abstracts hydrogen from benzeneselenol. The intermediacy of selenohemiacetal is supported by a quantitative reduction of α-methoxybenzyl phenyl selenide, which is used as a model compound of the intermediate.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010208
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  • 55
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    The effect of hydrophobic-lipophilic interactions on chemical reactivity. 11. The dependence of the wrapping-up capability of sodium carboxymethylamylose on its degree of substitution (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 133-141 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The dependency of the wrapping-up capability of sodium carboxymethylamylose (NaCMA) on its degree of substitution (D. S. = 0·00, 0·12, 0·18, 0·24, 0·29, 0·35 and 0·41) have been studied, using two guest species, iodine and cetyl-trimethylammonium bromide (CTAB). The λmax values of NaCMA-iodine helical inclusion complexes decrease with increasing D. S. values and the amounts of encapsulated iodine by NaCMA as measured by amperometric titrations also decrease with increasing D. S. values. With CTAB as the substrate, the largest number of binding sites, n, and the dissociation constants Kd have been determined by the method of surface tension versus the CTAB concentration plots. The results show that n decreases while Kd increases with increasing D. S. values. All these observations point to the fact that the wrapping-up capability of NaCMA decreases with increasing degrees of substitution. The results are discussed in terms of host-guest and host-solvent hydrophobic-lipophilic interactions as well as intramolecular hydrogen-bonding.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010303
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  • 56
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    Reaction branching as a mechanistic alternative to tunneling in explaining anomalous temperature-dependencies of kinetic isotope effects (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 161-167 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The temperature-dependence of the kinetic isotope effects for branched reactions proceeding via a common intermediate has been simulated by calculations. It is shown that, under certain conditions, anomalously small isotope effects on the Arrhenius preexponential factors, as well as unusually large observed isotope effects, may originate from the branching.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010306
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    Non-planar structures of the pentafluoroallyl and 1,1-difluoroallyl anions (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 153-160 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structures of the allyl anion (1) and two fluoro-substituted derivatives, perfluoro (2) and 1,1-difluoro (3) have been calculated by ab inito molecular orbital theory. Geometries were gradient optimized, and force fields and an MP-2 correlation correction were determined at stationary points. The calculations were done with a double zeta basis set augmented by d functions on carbon (DZ + Dc). Final self-consistent field (SCF) and MP-2 energy calculations were done with the DZ + Dc basis set augmented by diffuse functions. The ground state of 1 is the planar allyl anion (C2v). The rotation barrier in 1 is 21·1 kcal/mol at the MP-2 level. The cyclopropyl carbanion is 27·0 kcal/mol higher in energy at the MP-2 level. The perfluoroallyl anion is not planar, and the rotated structure is 25·7 kcal/mol more stable than the C2v structure at the MP-2 level. The lowest energy structure on the potential energy surface for 2 is the perfluorocyclopropyl carbanion which is 27·8 kcal/mol more stable than the C2v structure at the MP-2 level. The 1,1-difluoroallyl anion is also not planar. Here the most stable structure on the potential energy surface is the rotated allyl anion which is 8·3 kcal/mol more stable than the all-planar allyl anion structure.
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    URL: http://dx.doi.org/10.1002/poc.610010305
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    Nonplanar phenyl ring and inverse order of solvolytic reactivity for tertiary benzylic substrates (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 241-245 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The rates of solvolysis of l-aryl-l-phenyl-2,2-dimethylpropyl(1) p-nitrobenzoates and of aryldiphenylmethyl-p-nitrobenzoates (2) were measured in 80% acetone. An inverse order of reactivity, kp-CF3/km- CF3 〉 l was observed for 1 but not for 2. The X-ray crystallogoraphic study of the parent compounds, l,l-diphenyl-2,2-dimethylpropyl-p-nitrobenzoate (1b) and triphenylemethyl benzoate (3b), and of 2-phenyl-2-propyl-p-nitrobenzoate (4) indicated that in the highly congested system 1 both phenyl rings were nonplanar, whereas the phenyl rings in 3 and 4 were essentially planar.
    Additional Material: 4 Tab.
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    URL: http://dx.doi.org/10.1002/poc.610010407
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  • 59
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    NMR studies on the restricted rotation of 1-[2-(1-phenyl) propyl]-2,5-dimethylpyrrole derivatives (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 185-190 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: From the 1H-NMR spectra of the various pyrrole compounds, 1-substituted 2,5-dimethylpyrroles having two substituent groups on the carbon adjacent to the nitrogen atom were found to be very much hindered compounds. 1-[(1-Substituted)-2-phenylethyl]-2,5-dimethylpyrroles showed the restricted rotation, and the phenyl group of the most stable conformer was in close proximity to the pyrrole group due to dipole interaction. These NMR observations were supported by force field conformational analysis.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010402
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    Electron spin resonance study on radicals stabilized by the σ-π captodative effect1 (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 197-207 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: ESR spectra of l-cyano-2-(trimethylsilyl)ethyl and related radicals were recorded. Temperature dependent ESR spectra of these radicals revealed that electron-releasing trimethylsilylmethyl and electron-withdrawing cyano groups synergetically functioned to stabilize the radical centers due to σ-π captodative effects.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/poc.610010404
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    Acidities of benzyl phenyl sulfones and of the corresponding radical cations. Homolytic bond dissociation energies (BDEs) of α—C—H bonds in benzyl phenylsulfones (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 225-239 
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    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The excellent linearity (R2 = 0·997) of a plot of pKa values for 17 m- and p-substituted benzyl phenyl sulfones, GC6H4CH2SO2Ph, vs. those for the corresponding arylacetonitrile, GC6H4CH2CN, demonstrates that substituent solvation and substituent solvation assisted resonance (SSAR) effects for p-CN, p-COPh, and p-SPh are nearly identical in these two substrates. The PhSO2 group in PhCH2SO2Ph increases the BDE of the α-C—H bond by 2 kcal/mol, relative to toluene. The α-C—H bonds in GC6H4CH2SO2Ph sulfones are stabilized by 1-2 kcal/mol by acceptor G′s (m-CN, p-CN, m-CF3, p-CF3), but weakened by 1 and 5 kcal/mol, respectively, by donors (p-OMe and p-NMe2). The GC6H4CH2SO2Ph+. radical cation with G = H has a pKHA+. = -25. Its acidity is increased when G is an acceptor by as much as 9 to 10 kcal/mol (G = 3-CN, 3-CF3, 4-CF3, 4-NO2), but is decreased when G is a donor by as much as 33 kcal/mol (G = NMe2). When G = 4-SPh the radical cation is stabilized, relative to G = H, by a larger amount (25 kcal/mol) than when G = 4-OMe (18 kcal/mol). Structural changes along the series PhCH2SO2Ph, 2-naphthyl-CH2SO2Ph, 9-anthryl CH2SO2Ph cause negligible changes in the acidities of these acids, but sizable decreases in the acidities of the corresponding radical cations. Introduction of a phenylsulfonyl group into the methyl group of 9-methylanthracene or the 9-position of fluorene or xanthene increase the BDEs by 3, 2, and 7 kcal/mol, respectively. These effects of PhSO2 groups are compared and contrasted with those of CN groups.
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    URL: http://dx.doi.org/10.1002/poc.610010406
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    The lone-pair orbitals of triaziridine (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 267-273 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The PE spectra of four stable bicyclic triaziridines with trifluoromethyl, methyl, phenyl, spirocyclopentane and spirocyclohexane substituents are measured. From a comparison of these experimental data with MNDO calculations the energies and the interactions of the nitrogen lone-pair orbitals were obtained. The trifluoromethyl group may be reliably simulated by a fluorine atom. The ionization potentials are unexpectedly high and so are the cyclovoltammetric anodic potentials. The MNDO valence electron densities are in agreement with the comparatively small differences in the chemical shifts of the differently substituted nitrogens of the triaziridine rings.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010504
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    2,3:5,6-bis(ethylenedithio)- and bis(trimethylenedithio)-N,N′- dicyanoquinonediimines as new electron acceptors (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 275-280 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: In order to examine the substituent effect of ethylenedithio and trimethylenedithio groups on electron acceptors, the two title compounds were prepared in one step from the corresponding quinones. These species behave as weak π-electron acceptors owing to the electronic and sterical effects of the fused groups. Only the bis(ethylenedithio) derivative formed a charge-transfer complex with tetrathiotetracene, which showed a moderate electric conductivity of 2·0 × 10-2 S cm-1. In addition, both species oxidized copper, sodium, and potassium iodides to give the corresponding deeply colored metal salts, most of which were semiconductive. The naphtho analogs were similarly studied, but hardly served as electron acceptors.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010505
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  • 64
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010601
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  • 65
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    Photoinduced potentiometric response of poly(vinyl chloride)/spirobenzopyran/crown ether composite memberanes modified with urease (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 309-315 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Photoresponse of the poly(vinyl chloride) membranes, which contain spirobenzopyran and crown ether, covered with a urease layer was studied in the presence and absence of urea. In the absence of urea, UV light irradiation induced more than 160 mV of membrane potential change, whereas the photoresponse decreased with an increase in the concentration of urea in the solution. The effects of such operating variables as crown loading and pH and ionic strength in the aqueous phase on the potentiometric response were also elucidated in the presence of urea. The results were explicated using the fact that the local concentration on NH4+ and H+ ions changed as a result of the urease-catalyzed decomposition reaction of urea.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010602
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  • 66
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    Complex formation between 1,3,5-trinitrobenzene and 1,8-diazabicyclo-[5,4,0]-undec-7-ene (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 351-357 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The title reaction is an instance of a simple nucleophilic attack of neutral nitrogen on aromatic sp2 carbon. The kinetic data (obtained in dimethyl sulphoxide) are compared to the results reported by the literature for the same reaction of aliphatic amines. Some possible interactions (substrate/nucleophile, substrate/salt) preceding the attack of the nucleophile are discussed.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010605
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  • 67
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    Ultrastructure of the ovarian medulla in the newly hatched chick treated with human chorionic gonadotropin (1988)
    Springer
    Cell & tissue research 253 (1988), S. 665-670 
    Details
    ISSN: 1432-0878
    Keywords: Ovary ; Steroid-secreting cells ; Ultrastructure ; Chorionic gonadotropin ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of the ovarian medulla of the newly hatched white leghorn chick were studied in control animals and compared with chicks that were treated with human chorionic gonadotropin during embryonic development. The ovarian medulla was mainly occupied by epithelial cells which formed cords or islets surrounded by a basal lamina. Within this epithelial compartment, steroidogenic cells, poorly differentiated cells and a lacunary system could be recognized. When chicks were treated with human chorionic gonadotropin, steroidogenic cells became discernible; there was an increment in the amount of cytoplasm and the area of mitochondria. Poorly differentiated cells exhibited signs of stimulation, and transitional images suggested the transformation of these cells into steroidogenic cells. The epithelial cells of the lacunar system also displayed stimulated cytoplasmic organelles. Evidence was supplied suggesting that relatively undifferentiated cells persist in the ovarian medulla until hatching and can develop into steroidogenic cells under gonadotropic stimulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00219758
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  • 68
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    Morphology of smooth muscle cells in the rat thoracic duct (1988)
    Springer
    Cell & tissue research 251 (1988), S. 243-248 
    Details
    ISSN: 1432-0878
    Keywords: Thoracic duct ; Smooth muscle cell ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The three-dimensional cytoarchitecture and ultrastructure of the smooth muscle cells in the wall of the rat thoracic duct were investigated by scanning and transmission electron microscopy. The muscle layer basically consists of a single layer of circularly arranged cells. The smooth muscle cell is fusiform or ribbon-like in shape, as in veins or venules with a similar or smaller diameter. Connections by spinous processes are observed between adjacent muscle cells along their length. Spot-like membrane contacts frequently occur in areas where facing membranes are closely apposed. These are thought to be gap junctions and may be responsible for electrical coupling and mechanical attachment. Large invaginations arranged regularly in rows on the surface of the smooth muscle cells can be observed. These invaginations are closely associated with a flattened sarcoplasmic reticulum, and caveolae tend to open into the invaginations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215831
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  • 69
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    The pattern of organization of intermediate filaments and their asymmetrical association with dense bodies in smooth muscle of an ascidian Halocynthia roretzi (1988)
    Springer
    Cell & tissue research 252 (1988), S. 23-32 
    Details
    ISSN: 1432-0878
    Keywords: Smooth muscle ; Intermediate filaments ; Dual network ; Ultrastructure ; Ascidian ; Halocynthia roretzi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An extensive network of intermediate filaments that interconnected cytoplasmic dense bodies and connected the dense bodies to the cell surface was revealed in double-fixed, tannic acid-stained preparations of ascidian smooth muscle. The filament network ran through spaces in the continuous network of myofibrils, connecting them longitudinally, obliquely and transversely to form an intimately associated, dual network. In their transverse passage, the intermediate filaments ran across myofibrils along I-zones exclusively, interconnecting successive dense bodies. The pattern of attachment of intermediate filaments to dense bodies was predominantly “one-sided.” The filaments, which themselves were not incorporated into the contractile apparatus, remained folded or unfolded between myofibrils and between sarcomere-like structures in synchrony with the contraction-relaxation cycles. These results suggest that the intermediate filaments mechanically maintain the organization and arrangement of myofibrils via an intimate association with the myofibrils in the regions of the dense bodies, in such a way that the filaments do not impede muscle function. Based on these observations, a new model for the network of intermediate filaments in smooth muscle cells is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213822
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  • 70
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    Electron-microscopic immunocytochemistry of 5-hydroxytryptamine in the ascidian endostyle (1988)
    Springer
    Cell & tissue research 253 (1988), S. 137-143 
    Details
    ISSN: 1432-0878
    Keywords: Endostyle ; Ultrastructure ; Immunocytochemistry ; 5-Hydroxytryptamine ; Granules ; Ciona intestinalis ; Corella parallelogramma, (Tunicata) ; Ascidia mentula (Tunicata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The cellular and subcellular distribution of serotonin (5-hydroxytryptamine, 5-HT) in the endostyle of three species of ascidians, Ciona intestinalis, Corella parallelogramma, Ascidia mentula, was studied by light-(immunoperoxidase) and electron-microscopic (immunogold) immunocytochemistry. At the light-microscopic level 5-HT-like immunoreactivity (5-HT-LI) was exclusively found in cells located in the lateral portion of the endostyle, between zone 7, known to have iodinating capacity, and zone 8, which consists of ciliated cells. At the electron-microscopic level, the 5-HT-immunoreactive cells were found to correspond to cells containing polymorphous, dense granules, 100–300 nm in diameter. The granules were located in the supranuclear cytoplasm facing the endostyle lumen as well as in the infranuclear cytoplasm facing the extracellular space. Quantification showed that the 5-HT-LI was considerably higher (13–67 times) in cytoplasmic areas containing granules as compared to areas devoid of granules. Most, but not all, of the 5-HT-LI was associated with the dense core of the granules. In conclusion, serotonin-containing cells are located in the peripheral portion of the endostyle, between zones 7 and 8. Serotonin is stored in cytoplasmic granules that are present both in the apical and basal cytoplasm. This suggests the possibility that the cells are bipolar and secrete serotonin both in a basal direction to the extracellular space, and in an apical direction to the pharyngeal lumen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221748
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  • 71
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    Effect of live and heat-killed bacteria on the secretory activity of Paneth cells in germ-free mice (1988)
    Springer
    Cell & tissue research 251 (1988), S. 87-93 
    Details
    ISSN: 1432-0878
    Keywords: Paneth cells ; Ultrastructure ; Morphometry ; Facultative anaerobes ; Germ-free mice
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Germ-free mice were given live or heat-killed facultative anaerobes, and the ultrastructure of ileal Paneth cells was quantitatively examined with special reference to secretory granules showing a bipartite substructure (central core and peripheral halo). After administering live or heatkilled bacteria, there was a decrease in the area occupied by the cores of secretory granules in Paneth cells, and exocytosed core material was observed in the crypt lumen. There were no changes in the area occupied by the halo of secretory granules. None of the examined Paneth cells phagocytosed bacteria. It is concluded that certain bacteria may affect the secretion of antibacterial agents contained in the secretory granules of Paneth cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215451
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  • 72
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    Structure of radical intermediates appearing in the grignard reaction of monoketones (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 21-27 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The structure of radical intermediates appearing in the reactions of MeMgBr with aromatic monoketones was investigated by using ESR and visible spectroscopy. Stable radical intermediates in the reacting solutions were assigned to the dimeric radical ion pairs.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010104
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  • 73
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    Circular dichroism of In-Situ trinuclear organotransition metal complexes with optically active ligands (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 33-38 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Several Cotton effects are developed within absorption bands of trinuclear organotransitionmetal complexes in the presence of acids, diols, amines and aminoalcohols even in the case of bulky substituents on nitrogen; with monohydroxy compounds no circular dichroism could be detected.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010106
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  • 74
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    Marcus-grunwald theory and the nitroalkane anomaly (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 29-31 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The Disparity reaction proposed in a recent application of Marcus-Grunwald theory to nitroalkane ionization is shown to put the reaction's transition state in an energy-diagram region where electronic rearrangement leads proton transfer, contrary to experimental evidence; it is suggested that addition of solvent reorganization to electronic rearrangement as the second reaction progress variable would remedy this situation.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010105
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  • 75
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    Reaction of triethylsilyl radical with sulfides, a laser flash photolysis study (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 39-46 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Triethylsilyl radical was generated by laser flash photolysis of a 1:1 (v/v) solution of triethylsilane and di-tert-butyl peroxide. The silicon centered radical was reacted with sulfides to give carbon centered radicals by displacement at sulfur. The carbon radicals were readily detected by their transient absorption spectra. The absolute rate of reaction of triethylsilyl radical with 9-fluorenylphenylsulfide, di-n-butylsulfide, di-sec-butyl sulfide, di-tert-butyl sulfide and di-n-butyl disulfide are 2.40 ± 0.12 × 108 M-1S-1, 1.1 × 107±0.89×106M-1S-1, 8.79± 0.73×106M-1S-1, 3.29±0.18×106 M-1S-1, and 3.41±0.09×108 M-1S-1, respectively.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010107
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  • 76
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    Editorial (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. ii 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010102
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  • 77
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010101
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  • 78
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    Nucleophilic substitution at saturated carbon atoms. Mechanisms and mechanistic borderlines: Evidence from studies with neutral leaving groups (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 1-20 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Substrates with neutral leaving groups undergo unimolecular solvolysis in nonpolar solvents. Whereas t-alkyl substrates invariably solvolyze by a unimolecular mechanism, s-alkyl and primary alkyl substrates can undergo both uni and bimolecular reactions, and the bimolecular step can take place on either the substrate itself or on an intimate ion-molecule pair formed in either a pre-equilibrium or in a rate determining step. Study of reactions at borderlines indicates that the individual reaction types remain distinct and do not merge.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010103
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  • 79
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    Generation of α- oxo selenoaldehydes by treatment of α, α′ -diketo selenides with base (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 59-61 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Treatment of α, α′ -diketo selenides, which recently became readily obtainable, with base affords α-oxo selenoaldehydes and ketones. The seleno-carbonyl compounds thus formed are reactive transient species, but can be trapped by Diels-Alder reaction to give 3,6-dihydro-2H-selenapyran derivatives in moderate to good yields.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010110
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  • 80
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    Ethenediylidene-2,2′ -bis(1,3-dithiole) and butatriene-1,4-diylidene-2,2′-bis(1,3-dithiole) (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 47-51 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: This paper describes the synthesis and electrochemical behavior of dicationic salts of ethenediylidene-2,2′ -bis(1,3-dithiole) (3) and butatriene-1,4-diylidene-2,2′ -bis(1,3-dithiole) (4). These are expected as donor components for developing organic conducting and superconducting materials, on the grounds of high electron donating ability and of rigid skeletal structure with two and four cumulenic carbons inserted between two 1,3-dithioles. These salts were obtained in good overall yields by several steps starting from (2-morpholino-4,5-dimethyl or -diphenyl)-1,3-dithiolylium salt. From the 1H and 13C NMR, and electronic spectra it is suggested that the π conjugation between two 1,3-dithiolylium ions through an acetylenic bond is less effective than that through an olefinic bond of the corresponding salts of ethanediylidene-2,2′ -bis(1,3-dithiole) (1) and 2-butene-1,4-diylidene-2,2′-bis(1,3-dithiole) (2). The cyclic voltammetric study shows that the corresponding radical cations, and in particular 3 and 4, are less stable even at -40°C, thus providing reasons for our current lack of success in isolation of 3 and 4. From comparison of the first redox potentials of neutral species, it is deduced that the donating ability increases in the order of TTF 〈 1 ⋍ 2 ≲ 3 ≪ 4.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010108
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  • 81
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    Reaction of sulfur ylides with elemental sulfur and selenium. Aspects and mechanistic considerations (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 53-57 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The reaction of sulfur ylides with elemental sulfur or selenium initially affords thio- or seleno-carbonyl compounds, which then react with starting ylides to give episulfides or episelenides from which the heteroatom (sulfur or selenium) is extruded to give olefins as the final product. In the case of carbonyl-stabilized ylides, the resulting thio- or seleno-carbonyl compounds react with starting ylides to afford 1,3-oxathioles or 1,3-oxaselenoles as previously reported. Supporting evidence for the intermediacy of thio(seleno)-carbonyl compounds and episulfides (episelenides) is presented.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010109
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    Masthead (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988) 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010201
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  • 83
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    Study on 5, 15-dialkylporphyrins interconversion between two conformers in solution (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 63-73 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Novel structural features of 5, 15-dialkylporphyrins in solution are described. The 1H-NMR spectra of these compounds showed broad signals at room temperature, which split into two sets of signals at lower temperatures. This unusual phenomenon was ascribed to a dynamic interconversion between tow distorted structures. The 5, 15-dialkylporphyrin has a distorted ring due to the steric hindrance between the 5(or 15)-alkyl group and the 3, 7(or 13, 17)-alkyl groups and, depending on the position of the 5, 15-alkyl groups relative to the average ring plane, can exist in two conformations; syn (where the two alkyl groups are on the same side of the ring plane) and anti (on the opposite sides). Preliminary kinetic study of this interconversion using the NMR line shape analyses is also reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010202
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  • 84
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    Thiophilic reactions of 2,4,6-tri-t-butylphenyllithium with carbon disulfide and thiophosgene (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 75-81 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Highly sterically demanding 2,4,6-tri-t-butylphenyllithium (1) reacts with carbon disulfide to give 1,2-dibutylthio-1,2-bis(2,4,6-tri-t-butylphenylthio) ethene (3), l-butylthio-1-(2,4,6-tri-t-butylphenylthio)pent-l-ene (4), and 2-butylthio-3-(2,4,6-tri-t-butylphenylthio)-1,3-dithiole-2-thione (5) when 1 is prepared by the reaction of 1-bromo-2,4,6-tri-t-butylbenzene with n-butyllithium. When the reaction is carried out using 1 prepared from 2 and t-butyllithium and then quenched with l-iodoethane, 2-ethylthio-3-(2,4,6-tri-butylphenylthio)-1,3-dithiole-2-thione and 1,2-diethylthio-1,2-bis(2,4,6-tri-t-butylphenylthio) ethene are produced. The formation of all these products can be explained in terms of initial thiophilic attack of 1 on the sulfur of carbon disulfide and an intermediate with a dual property of carbanion and carbene (i.e., ArSC(Li)(=S) ⇌ ArSC̈SLi) is suggested. The reaction of 1 with thiophosgene affords 1,2-dichloro-1,2-bis(2,4,6-tri-t-butylphenylthio) ethene, bis(2,4,6-tri-t-butylphenylthio)acetylene, and 1-chloro 2,4,6-tri-t-butylbenzene, the first two of which are explained to be formed by thiophilic attack of 1 with thiophosgene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010203
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    Intramolecular orientation at the micellar interface: Control of norrish type I and type II reactivity of benzoinalkylethers via conformational effects (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 91-102 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photolysis of benzoinalkylethers 1-5 solubilized in detergents show a significant deviation from the course of reaction in isotropic organic solvents. Remarkable difference in photobehaviour is noticed between the short chain (1-3) and the long chain (4 and 5) benzoinalkylethers in the micellar media. However, the influence of the micellar media on the photobehaviour of alkyldeoxybenzoins 6 and 7 was small. The importance of ‘cage effect’ in controlling the product distribution was evident from its dependence on the micellar size and on the occupancy number. More importantly, a comparative analysis of the photobehaviour of the ketone 1-7 reveals that the micellar interface can be used to control the conformations of organic molecules.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010205
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  • 86
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    Electronic Resource
    Theoretical studies on the acylation reactions of ammonia by ketenes: Determination of reactivity by molecular orbital theory (part 54) (1988)
    Chichester : Wiley-Blackwell
    Journal of Physical Organic Chemistry 1 (1988), S. 83-90 
    Details
    ISSN: 0894-3230
    Keywords: Organic Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Theoretical studies on the reactions of ammonia with ketene and dimethylketene using the MNDO method are reported. The single step addition of ammonia to the olefinic bond of ketenes was found to provide a lower energy-barrier path than the two step carbonyl addition mechanism. The barrier height was lower in the reaction of keten compared with that of dimethylketene in support of the faster rate of solution phase reactions of aniline and ketenes. The deformation energies of reactants had an overwhelming influence in determining the activation barriers in all the reactions investigated.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/poc.610010204
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  • 87
    Electronic Resource
    Electronic Resource
    Sublethal muscle fibre injuries after high-tension anaerobic exercise (1988)
    Springer
    European journal of applied physiology 57 (1988), S. 360-368 
    Details
    ISSN: 1439-6327
    Keywords: Humans ; Skeletal muscles ; Anaerobic exercise ; Histocytochemistry ; Ultrastructure ; Muscle cell injury
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The vastus lateralis muscles of eleven male elite sprinters (17–28 years) were investigated in order to examine the impact of high tension anaerobic muscular work on muscle fibre fine structure. In an attempt to reproduce the training regimen six subjects ran 20 repetitions of 25 s on a treadmill with 2 min 35 s in between, at a speed corresponding to 86% of their personal best 200 m time. PAS-stained sections of biopsies taken approximately 2 h after training generally indicated glycogen depletion in type 1 and type 2B fibres. At the light microscopic level, no signs of inflammation or fibre rupture were observed. However, at the ultrastructural level, frequent abnormalities of the contractile material and the cytoplasmic organelles were detected. Z-band streaming, autophagic vacuoles and abnormal mitochondria were the most conspicuous observations. Control specimens from sprinters who did not perform the acute exercise routine also displayed structural deviations, although to a lesser degree. It is hypothesized that during sprint training the leg musculature is put under great mechanical and metabolic stress which causes the degenerative response reported here.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00635996
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  • 88
    Electronic Resource
    Electronic Resource
    Cortical cytoskeleton of the flagellateProteromonas lacertae: Interrelation between microtubules, membrane and somatonemes (1988)
    Springer
    Protoplasma 142 (1988), S. 46-54 
    Details
    ISSN: 1615-6102
    Keywords: Cytoskeleton ; Plasma membrane ; Microtubules ; Ultrastructure ; Freeze-fracture ; Flagellates ; Proteromonas lacertae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The anterior half of the cell surface of the parasitic flagellateProteromonas lacertae is corrugated while the posterior half is covered by hair-like appendages, called somatonemes. In the anterior part, the cortical microtubules are lined by a zig-zag shaped microfibril. Here, these two structures seem to be separated from the plasma membrane. In the posterior half of the cell the somatonemes, analogous to the mastigonemes of chrysophytes, are anchored to the cortical microtubules by paired small deposits of dense material. This was clearly demonstrated by Triton X 100 treatment which solubilized the plasma membrane but left the somatonemes attached to the cortical microtubules. Freeze-fracture images revealed the alignment of clustered intramembrane particles on the P-face of the plasma membrane which correspond to the attachment sites of the somatonemes, seen as dots in thin sections. The ER-derived membrane-associated somatonemes are probably linked to the cortical microtubules by anchoring proteins which are part of the plasma membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01273225
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  • 89
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    Electronic Resource
    Dynamics of the microtubular cytoskeleton in the green algaAphanochaete magna (Chlorophyta). I. Late mitotic stages and the origin and development of the phycoplast (1988)
    Springer
    Protoplasma 142 (1988), S. 176-187 
    Details
    ISSN: 1615-6102
    Keywords: Aphanochaete ; Astral microtubules ; Immunofluorescence ; Phycoplast ; Spindle breakdown ; 3-D reconstruction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The spatial and temporal organization of the microtubular cytoskeleton at the transitional stage of mitosis and cytokinesis has been studied in the chaetophoralean green algaAphanochaete magna using indirect immunofluorescence light microscopy and transmission electron microscopic analysis of serial sections including computer-aided three-dimensional reconstruction. At late mitosis, elaborate asterlike microtubule systems including bundles interconnecting both centriolar regions are present. These systems disappear a the onset of interzonal spindle disintegration. The incipient phycoplast consists of a star-shaped microtubule assemblage projecting from the intact interzonal spindle. It develops strongly at the time of spindle disintegration, later on it becomes compressed by daughter nuclei movement. Cell plate formation is associated with a two-dimensional phycoplast. Phycoplast microtubules remain for a while associated with the completed cross wall but finally they depolymerize. The general occurrence of astral microtubule systems (includingA. magna) is evaluated. The subsequent developmental stages of the phycoplast, formation, maturation and depolymerization, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01290874
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  • 90
    Electronic Resource
    Electronic Resource
    Morphology ofEntomophthora muscae protoplasts grownin vitro (1988)
    Springer
    Protoplasma 146 (1988), S. 166-173 
    Details
    ISSN: 1615-6102
    Keywords: Entomophthorales ; Entomophthora muscae ; Ultrastructure ; Cytochemistry ; Protoplast ; in vitro growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Entomophthora muscae (C.) Fres. can be grownin vitro as protoplasts. Light and electron microscopical studies of thein vitro developed protoplasts have demonstrated the absence of an organized wall over the protoplasmic Con A-positive membrane at all stages of growth. The cytological organization is typical of the Entomophthorales with condensed chromatin in the interphase nuclei and small eccentric metaphase spindles. Long strands of endoplasmic reticulum, microubules and vesicles surrounding the plasmalemma may be involved in maintaining the precise shape ofE. muscae protoplast. Starvation of the fungus induces the formation of hyphal bodies after deposition of Con A- and WGA-positive wall material at the plasmalemma surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405926
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  • 91
    Electronic Resource
    Electronic Resource
    Effects ofl-propionylcarnitine on electrical and mechanical alterations induced by amphiphilic lipids in isolated guinea pig ventricular muscle (1988)
    Springer
    Heart and vessels 4 (1988), S. 197-206 
    Details
    ISSN: 1615-2573
    Keywords: l-Propionylcarnitine ; Amphiphile ; Action potential ; Ultrastructure ; Guinea pig ventricular muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We examined the effects ofl-propionyl-carnitine (Prop.C), a short-chain acylcarnitine, on amphiphile (l-lysophosphatidylcholine orl-palmitoylcarnitine)-induced electrophysiological and ultrastructural changes in isolated guinea pig ventricular papillary muscles, under acidic conditions (pH 6.9). Conventional microelectrode, tension-recording, and electron microscope techniques were used. Both amphiphiles, at a concentration of 10−4 M, significantly decreased the resting membrane potential, action potential amplitude, and action potential duration, but increased the developed and resting tension. Such amphiphile-induced electrical changes were not observed in muscles pretreated with the beta-blocker, atenolol, although the mechanical changes remained unaffected. The application of Prop.C (10−2 M), in the continued presence of the amphiphiles caused a return of the action potential duration and the developed tension to the control level. However, the resting potential and action potential amplitude remained unaffected; in fact, the maximum upstroke velocity ( $$\dot V_{max} $$ ) of the action potential tended to decrease further. Pretreatment with Prop.C prevented all the amphiphile-induced electrophysiological and mechanical changes, except for $$\dot V_{max} $$ . Electron microscopic studies revealed that amphiphile-induced ultrastructural changes were prevented, at least in part, in the presence of Prop.C. Thus, Prop.C antagonizes some of deleterious effects of amphiphiles, such as lysophosphatidylcholine and palmitoylcarnitine, upon the electrical and mechanical activities of the ventricular muscle, under acidic conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02058587
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  • 92
    Electronic Resource
    Electronic Resource
    Metabolism of P-particles (polysaccharide particles) in mature pollen grains ofEryngium campestre L. (Apiaceae) (1988)
    Springer
    Protoplasma 146 (1988), S. 65-71 
    Details
    ISSN: 1615-6102
    Keywords: Apiaceae ; Eryngium campestre ; Metabolism ; Pollen grain ; P-particle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The metabolism of P-particles (polysaccharide particles) was investigated in mature pollen grains ofEryngium campestre L. Numerous P-particles, originating from dictyosome activity, are found to be accumulated near the apertures, followed by mitochondria. A single layer of ER profiles seems to prevent the fusion of the P-particles with the intine. Instead of this, they fuse with each other forming nonmembrane-bounded polysaccharide-aggregates, which subsequently change their granulated structure to an amorphous. Mitochondria together with small vesicles are involved in the conversion-process. The so formed wall precursors pass through the ER and fuse into the intine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405914
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  • 93
    Electronic Resource
    Electronic Resource
    Ultrastructural aspects of the hyphal tip ofSclerotium rolfsii preserved by freeze substitution (1988)
    Springer
    Protoplasma 146 (1988), S. 143-149 
    Details
    ISSN: 1615-6102
    Keywords: Hyphal tip ; Ultrastructure ; Freeze substitution ; Sclerotium rolfsii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hyphal tip ofSclerotium rolfsii was examined after fixation by freeze substitution. The Spitzenkörper consisted of a dense mass of apical vesicles and microvesicles surrounding a vesicle-free zone. Linear arrangements of microvesicles were occasionally observed within the Spitzenkörper. Abundant microfilaments were seen within the Spitzenkörper region, often in close association with apical vesicles and microvesicles. Microtubules passed through the Spitzenkörper and terminated at the plasmalemma at the extreme hyphal apex. Filasomes were mostly observed within the apical region and were in close proximity to the plasmalemma. Rough ER, mitochondria, microtubules, and vacuoles were abundant in the subapical region and were usually oriented parallel to the long axis of the hypha. Ribosomes were aligned on the outer surfaces of mitochondria. Golgi body equivalents were observed throughout the subapical region and appeared as inflated cisternae of varying shapes and electron opacities. Relationships to other basidiomycetous hyphal tip cells are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01405923
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  • 94
    Electronic Resource
    Electronic Resource
    Three-dimensional organization of the plasmalemmal vesicular system in directly frozen capillaries of the rete mirabile in the swim bladder of the eel (1988)
    Springer
    Cell & tissue research 254 (1988), S. 17-24 
    Details
    ISSN: 1432-0878
    Keywords: Endothelium ; Swim bladder ; Capillaries ; Vesicles ; Ultrastructure ; Cryofixation ; Anguilla rostrata (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Several recent studies comparing chemically fixed and cryofixed endothelium have indicated that glutaraldehyde fixation may result in increases in the population of “vesicles” in the cytoplasm. Other reports based on ultrathin serial-section reconstruction of chemically fixed endothelium have revealed that the vesicular system is comprised of interconnected membranous compartments, which are ultimately continuous with either cell surface but do not extend across the endothelial cell. In this study, we have investigated the three-dimensional organization of the vesicular system in directly frozen, freeze-substituted capillaries of the rete mirabile from the swim bladder of the eel, specifically using the same block of embedded capillaries in which frozen capillaries had previously been found to contain less “vesicles” than chemically fixed capillaries. The results show that essentially all vesicles remain inter-connected with each other and are part of two separate sets of invaginations from the luminal and abluminal cell surface like in chemically fixed tissue. Any increase in vesicle number resulting from glutaraldehyde fixation does not affect the overall three-dimensional organization of the vesicular system in these endothelial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220012
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  • 95
    Electronic Resource
    Electronic Resource
    Lymphocytes of the intestinal mucosa of chickens (1988)
    Springer
    Cell & tissue research 251 (1988), S. 189-195 
    Details
    ISSN: 1432-0878
    Keywords: Lymphocytes ; Epithelium ; Mast cells ; Granular leukocytes ; Basophils ; Ultrastructure ; Chicken
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination, by light and electron microscopy, of the morphology and the staining properties of intraepithelial lymphocytes from the intestine of the chicken revealed a population of lymphoid cells, of which a proportion (up to 20%) is granulated. The majority of cells were immunoreactive with anti-T cell serum and can therefore be considered to be related to T-lymphocytes, but they did not proliferate when cultured with phytohaemagglutinin. The granulated cells were identical to those previously designated globule-containing leukocytes, but were distinct from mast cells in their morphology, staining reactions and the stability of the granules in different fixatives and buffers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215464
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  • 96
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    Structural changes produced in Kupffer cells in the rat liver by injection of lipopolysaccharide (1988)
    Springer
    Cell & tissue research 251 (1988), S. 205-214 
    Details
    ISSN: 1432-0878
    Keywords: Kupffer cells ; Granulocytes ; Ultrastructure ; Lipopolysaccharide ; Liver ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of Kupffer cells has been studied at various times after an intravenous injection of lipopolysaccharide of Salmonella abortus equii. The most prominent effects were: an increase in the number and dimensions of phagocytic vacuoles (often containing ingested LPS and neutrophilic granulocytes); mitochondrial damage, including disintegration of the matrix and cristae; an increase in the amount of dilated, lucent rough endoplasmic reticulum; presence of fat droplets in the cytoplasm. Five days after injection of lipopolysaccharide, the Kupffer cells had resumed their normal ultrastructure. Several minutes after injection of lipopolysaccharide, platelets adhered to the Kupffer and endothelial cells. Between one and six hours, neutrophilic granulocytes accumulated in the liver sinusoids. The resulting obstruction of the hepatic microcirculation most probably affected cellular ultrastructure by ischaemia. At three days, the number of Kupffer cells was doubled, and increased further at later time intervals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215466
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  • 97
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    Electronic Resource
    An ultrastructural study of mitosis and cytokinesis in normal ‘resting’ human breast (1988)
    Springer
    Cell & tissue research 252 (1988), S. 581-587 
    Details
    ISSN: 1432-0878
    Keywords: Normal resting breast ; Ultrastructure ; Mitosis ; Cytokinesis ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The parenchyma of the normal “resting” human breast was examined by electron microscopy to characterize the cells undergoing mitosis and the mechanism by which the normal tissue architecture is maintained during this process. In this study of 112 mitotic cells, it was found that the mitotic cells were luminally positioned, polarised epithelial cells with no evidence of myoepithelial cell division. Ultrastructurally, the nuclear and cytoplasmic changes were consistent with previous reports of mitosis in other tissues. However, unlike all previous reports, two specific orientations of the nuclear spindle and thus the planes of cytokinesis were observed. In a few cases the spindle formed parallel to the lumen and division resulted in two luminally positioned daughter cells. However, in the majority of mitotic cells the spindle was approximately at right angles to the lumen and this orientation resulted in a luminally and a basally positioned daughter cell. It is proposed that the abnormally positioned basal daughter cell could develop into a myoepithelial cell or undergo deletion (apoptosis). Thus the two orientations of mitosis may explain the mechanism by which the epithelial and myoepithelial cell populations were maintained by a single progenitor cell without disrupting the integrity of the tissue architecture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216645
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  • 98
    Electronic Resource
    Electronic Resource
    Melanophore death and disappearance produces color metamorphosis in the polychromatic Midas cichlid (Cichlasoma citrinellum) (1988)
    Springer
    Cell & tissue research 253 (1988), S. 9-14 
    Details
    ISSN: 1432-0878
    Keywords: Chromatophores ; Color change ; Ultrastructure ; Melanophores ; Macrophages ; Xanthophores ; Cichlasoma citrinellum (Teleostei: Cichlidae)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary We describe the histological basis of color metamorphosis in the polychromatic Midas cichlid, Cichlasoma citrinellum. Eight percent of the individuals in a natural population transform from gray with black markings to orange, simultaneously losing their ability to adjust coloration in response to background and social context. This trait is inherited. Light- and electron microscopy revealed that this transformation is a two-step process. First, the melanophores die, then macrophage-like cells remove the debris. As a result of this initial process, the underlying xanthophores become visible, producing the orange coloration. A similar process may occur in individuals that further transform to white, or go directly from gray to white.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221733
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  • 99
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    Electronic Resource
    Neurosecretory centers from the eyestalk of Siriella armata M. Edw. (Crustacea: Mysidacea): ultrastructural variations during normal and experimentally inhibited molt cycle (1988)
    Springer
    Cell & tissue research 254 (1988), S. 381-391 
    Details
    ISSN: 1432-0878
    Keywords: X-organ ; Sinus gland ; Ultrastructure ; Cyclic activity ; Siriella armata (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the medulla interna-medulla externa X-organ (MI-ME Xo)-sinus gland (SG) complex in the eyestalk of Siriella armata is described during the normal and the experimentally inhibited molt cycle. In the normal SG, four types of neurosecretory axon terminals, each containing distinguishable neurosecretory granules, can be described. Thus, type-2 granules are synthesized by G1 neurons forming the MI-ME Xo. The cell bodies and axonal endings of these cells in the sinus gland have been examined at the following molt stages: intermolt (stage C4), premolt (D0 and D2), and postmolt (A1, A2 and B). Changes in ultrastructure of the G1 cells have been monitored and correlated to inhibitions of the molt-and reproductive cycle produced by electrocauterization of the MI-ME Xo. The results obtained suggest that the neurosecretion from the G1 cells exerts a positive influence on molt and brood preparation. The occurrence of a distal group of G1 cells whose axons terminate at a different site from the SG suggests that the neural factors of the MI-ME Xo are diverse and control different physiological activities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00225810
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  • 100
    Electronic Resource
    Electronic Resource
    Primary malignant astrocytoma of the cerebellum in children (1988)
    Springer
    Child's nervous system 4 (1988), S. 306-309 
    Details
    ISSN: 1433-0350
    Keywords: Malignant astrocytoma ; Glioblastoma ; Cerebellum ; Children ; Cytofluorometric DNA analysis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The case of a 1-year-old girl with primary malignant astrocytoma of the cerebellum is presented with special reference to ultramicroscopic study and cytofluorometric DNA analysis. The routine light microscopic study was not pathognomonic because of the immaturity of the composing cells. The glial fibrillary microfilaments characteristic of astroglial cells were confirmed by means of electron microscopy. Cytofluorometrically, the DNA histogram of this case revealed a prominent peak in the 4C region, with considerable dispersion to the 8C region, indicating the polyploidic and heterogeneic pattern of malignant tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271931
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