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  • 1995-1999
  • 1990-1994  (1,095)
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  • 1
    Electronic Resource
    Electronic Resource
    Giant inflammatory polyps associated with idiopathic inflammatory bowel disease (1990)
    Springer
    Diseases of the colon & rectum 33 (1990), S. 773-777 
    Details
    ISSN: 1530-0358
    Keywords: Giant inflammatory polyp ; Idiopathic inflammatory bowel disease ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Five cases of giant inflammatory polyps associated with idiopathic inflammatory bowel disease are reported. Polyps produced intestinal obstruction in three cases; consequently, surgery was performed. In a further two cases, intestinal bleeding was improved by endoscopic polypectomy. Electron microscopy showed fibroblasts, myofibroblasts, mast cells, lymphocytes, collagen fibers, capillaries, and venules. Remnants of the original mucosal epithelial cells, smooth muscle cells, and hypertrophic autonomous nerve plexuses were noted. Nerve fibers were interwoven with the matrix of the polyps. Mast cells were closely linked with vessels, nerves, and collagen fibers. They may have an important role in the excessive granulation, angiogenesis, and fibrotic process in giant inflammatory polyps.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02052325
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  • 2
    Electronic Resource
    Electronic Resource
    A monoclonal antibody (Mab 67) marks type B synoviocytes (1990)
    Springer
    Rheumatology international 10 (1990), S. 103-106 
    Details
    ISSN: 1437-160X
    Keywords: Synovium ; Synoviocytes ; Monoclonal antibody ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The functionally important lining cells of the synovium (types A and B synoviocytes) are the subjects of much study but have presented problems with their characterization and microscopical identification, particularly at the light level. Type A (macrophage-like) synoviocytes, however are more easily localized than the type B (fibroblast-like) variety because of the greater availability of antimacrophage antisera. We describe, using light and electron microscopy, a monoclonal antibody which in the synovial intimal layer is specific for type B synoviocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02274823
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  • 3
    Electronic Resource
    Electronic Resource
    Genetic variability associated with hovering time inTabanus nigrovittatus Macquart (Diptera: Tabanidae) (1990)
    Springer
    Journal of insect behavior 3 (1990), S. 579-587 
    Details
    ISSN: 1572-8889
    Keywords: Genetics ; polymorphism ; reproductive isolation ; hovering behavior ; Tabanus nigrovittatus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The salt marsh horse fly, Tabanus nigrovittatusMacquart, exhibits two nonoverlapping daily periods of hovering and mating activity, which are correlated with different environmental temperatures. Allelic and genotypic frequencies of hovering males collected during the two periods were compared by electrophoresis of three polymorphic enzyme loci. Approximately 26% of early-hovering males possessed a Pgmallozyme that was absent in our sample of late-hovering males. However, based on other allozyme loci, we found no evidence for reproductive isolation between early and late hoverers. All the genetic data are consistent with the hypothesis that the Pgmpolymorphism is associated with behaviorally and physiologically distinct groups of males that, by all other criteria, form a single Mendelian population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01052329
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  • 4
    Electronic Resource
    Electronic Resource
    Anatomically identical short-segment Hirschsprung's disease in three male siblings (1990)
    Springer
    Pediatric surgery international 5 (1990), S. 359-360 
    Details
    ISSN: 1437-9813
    Keywords: Hirschsprung's disease ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three male children with identical short-segment Hirschsprung's disease born to a young married couple are reported. There was no positive family history despite an extensive search. There were no associated abnormalities. Although sex-modified multifactorial inheritance, with males having a lower threshold of genes for expression of Hirschsprung's disease, is accepted, the identical expression of the disorder in the three siblings presented suggests a dominant, possibly X-linked gene with variable penetrance. Another possibility is that an identical micro-environmental factor was present prenatally resulting in all three boys having Hirschsprung's disease. This is the first report of three siblings with identical short-segment Hirschsprung's disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00177106
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  • 5
    Electronic Resource
    Electronic Resource
    Cellular schwannoma (1990)
    Springer
    Virchows Archiv 416 (1990), S. 237-248 
    Details
    ISSN: 1432-2307
    Keywords: Neurilemoma ; Pseudosarcoma ; Electron microscopy ; Immunohistochemistry ; Cytogenetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A series of 29 cellular schwannomas is described in terms of their clinical presentation and course, light and electron-microscopic appearance, immunohistochemical properties and cytogenetics. The study indicates that cellular schwannoma can be defined as a subtype of classical schwannoma, characterized by spindle cells forming a compact fascicular, sometimes fibrosarcoma-like growth pattern, a low mitotic activity, a generally moderate nuclear and cellular polymorphism and a high degree of Schwann cell differentiation as seen by electron microscopy and immunohistochemistry. The tumour is characteristically located close to the vertebral column, in the mediastinum or retroperitoneum and has a benign course. Occasionally bone destruction and neurological symptoms develop. The clinical appearance together with the high cellularity, fascicular pattern and mitotic activity had led to the erroneous diagnosis of a soft tissue sarcoma in a few cases, and cellular schwannoma may thus be considered to be a pseudosarcoma. Immunohistochemically, cellular schwannomas appear to deviate from classical schwannomas and malignant peripheral nerve sheath tumours by their expression of glial fibrillary acidic protein. The chromosome analysis revealed a normal diploid stemline karyotype, with a variety of abnormal clones, including one with monosomy 22.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01678983
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  • 6
    Electronic Resource
    Electronic Resource
    Non-functional malignant paraganglioma of the stomach (1990)
    Springer
    Virchows Archiv 417 (1990), S. 261-266 
    Details
    ISSN: 1432-2307
    Keywords: Stomach ; Paraganglioma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report the second case of a malignant paraganglioma of the stomach in a 56-year-old female patient. However, our case is the first investigated by immunohistochemistry and electron-microscopy. The tumour was characterized immunohistochemically by the presence of neurofilament protein, glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, chromogranin A, ACTH, leu-enkephalin and vasoactive intestinal polypeptide, and ultrastructurally by demonstration of neurosecretory granules and paranuclear intermediate filament whorls. Despite massive metastatic spread in the abdominal cavity, the patient is still alive 4 years after initial diagnosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600143
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  • 7
    Electronic Resource
    Electronic Resource
    An electron microscopic study of glomerular lesions in hereditary nephrotic mice (ICGN strain) (1990)
    Springer
    Virchows Archiv 417 (1990), S. 223-228 
    Details
    ISSN: 1432-2307
    Keywords: Mouse ; Nephrotic syndrome ; Hereditary nephritis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glomerular lesions in hereditary nephrotic mice (ICGN strain) were investigated by electron microscopy. The glomeruli of unaffected animals, which appeared normal by light microscopy, had developed an ultrastructural change in the glomerular capillary basement membrane (GCBM). There was a partial thickening of the GCBM with bilaminar splitting of the lamina densa and an electron-dense fibrillar material exhibiting cross-striations. In affected animals, light microscopy revealed a marked thickening of GCBM and an increase of mesangial matrix without cellular proliferaton. By electron microscopy, multilaminar splitting of the lamina densa in the thickened GCBMs and fusion of the epithelial foot processes were observed. In some severely affected animals, immune complex deposition was found in GCBM, but little if any was observed in other animals. In the end, the glomeruli were globally sclerosed. Our findings suggest that initial structural abnormalities in GCBM may play an important role in the onset and development of the disease, though subsequent events such as immune complex deposition would modify the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600137
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  • 8
    Electronic Resource
    Electronic Resource
    Histological and ultrastructural effects of cyclosporin A on normal human skin xenografted on to nude mice (1990)
    Springer
    Virchows Archiv 416 (1990), S. 505-511 
    Details
    ISSN: 1432-2307
    Keywords: Cyclosporin A ; Human skin xenografts ; Histology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cyclosporin A (CsA) is a potent immunosuppressant with a selective activity on T-helper lymphocytes. However, CsA also exerts biological effects on non-lymphoid cells (fibroblasts, endothelial and epithelial cells). CsA can inhibit in vivo and in vitro DNA synthesis of epidermal keratinocytes (EK) and induces in vivo morphological alterations of kidney epithelial cells. In the present study we investigated the in vivo effects of a short-term CsA treatment (50 mg/kg per day) on DNA synthesis (evaluated through 5-bromo-2′-deoxyuridine incorporation) and on the histological features of normal human skin xenografted (NHSX) on to congenitally athymic nude mice. When compared with control NHSX, CsA induced a statistically significant inhibition of DNA synthesis of NHSX EK. At the light- and electron-microscopic level, apart from a decrease in the thickness of the viable epidermis of NHSX (statistically non-significant), no noticeable differences between treated and control NHSX could be detected. EK, Langerhans cells and melanocytes appeared morphologically unaffected by CsA and no signs of acute toxicity (giant mitochondria, vacuolization, microcalcifications) were seen. These results suggest that CsA exerts a subtle effect on human EK; indeed, despite an unequivocal antiproliferative activity, no significant histological changes related to the acute CsA toxicity seem to be induced on the various epidermal cell types.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01600301
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  • 9
    Electronic Resource
    Electronic Resource
    Comparative histogenesis and morphogenesis of mucoepidermoid carcinoma and pleomorphic adenoma (1990)
    Springer
    Virchows Archiv 417 (1990), S. 405-417 
    Details
    ISSN: 1432-2307
    Keywords: Salivary gland ; Neoplasm ; Mucoepidermoid carcinoma ; Electron microscopy ; Histogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Current classifications of salivary gland tumors separate mucoepidermoid carcinoma from other neoplasms on the basis of a number of histological features, in particular the lack of participation of neoplastic myoepithelial cells. However, ultrastructural examination of low- and intermediate-grade mucoepidermoid carcinomas and pleomorphic adenomas reveals many common organizational and cellular features. Of prime importance is the relationship of intermediate cells to the luminal cells in mucoepidermoid carcinomas, which is remarkably similar to that seen between modified myoepithelial cells and luminal cells in pleomorphic adenomas. The results suggest that intermediate cells of mucoepidermoid carcinoma are the counterpart of the modified myoepithelial cells of pleomorphic adenoma. The generally accepted hypothesis that the former tumor develops from an excretory duct reserve cell, while the latter originates from an intercalated duct stem cell does not seem to be valid; pleomorphic adenoma and mucoepidermoid carcinoma appear to be closely related morphologically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01606029
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  • 10
    Electronic Resource
    Electronic Resource
    Ultrastructural quantitation of atubular and hypertrophic glomeruli in rats with lithium-induced chronic nephropathy (1990)
    Springer
    Virchows Archiv 417 (1990), S. 513-522 
    Details
    ISSN: 1432-2307
    Keywords: Atubular glomeruli ; Chronic nephropathy ; Electron microscopy ; Lithium ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The very heterogeneous population of glomeruli in rats with lithium-induced chronic nephropathy which includes small glomeruli without connection to a proximal tubule (atubular glomeruli) and large hypertropic glomeruli with connection to a normal proximal tubule, was studied at the ultrastructural level, using stereological methods. After 8 weeks of lithium treatment followed by 8 weeks without lithium the hypertrophic glomeruli showed no changes in their relative ultrastructural composition, including normal mesangium, basement membrane-like material and peripheral basement membrane. The absolute quantities of each component were, however, increased due to the increased volume of the glomeruli. The atubular glomeruli had increased volume fractions of mesangium, peripheral basement membrane, basement membrane-like material and epithelium, whereas the absolute quantities were decreased due to the decreased volume. The thickness of the basement membrane was within normal limits in the group of hypertrophic glomeruli but increased by 31% above controls in the group of atubular glomeruli. Both groups of glomeruli in lithium-treated animals showed normal mean foot process width, but with a slightly abnormal distribution. The atubular glomeruli showed a disproportionate large decrease in peripheral filtration surface and capillary length, compared with the reduction in glomerular volume, whereas the hypertrophic glomeruli showed changes in proportion with the increased volume.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01625732
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  • 11
    Electronic Resource
    Electronic Resource
    Neuropeptide Y- and substance P-like immunoreactive nerve fibers in the rat dura mater encephali (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 363-373 
    Details
    ISSN: 1432-0568
    Keywords: Neuropeptide Y ; Substance P ; Immunocytochemistry ; C-fibers ; Dura mater ; Dural sinus ; Meningeal arteries ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Density and pattern of nerve fibers with neuropeptide Y-like immunoreactivity (NPY-LI) and substance P-like immunoreactivity (SP-LI) in the rat dura mater encephali were investigated by light and electron microscopy using whole-mount preparations. NPY-LI fibers are observed throughout the encephalic dura mater. A remarkable net of NPY-LI nerve fibers is located in the walls of the sagittal and transverse sinuses. Beyond that NPY-LI network, distinct NPY-LI nerve fibers or plexus occur in the rostral falx, parietal dura mater of the olfactory bulb, supratentorial dura mater, parietal dura mater of the cerebellum, tentorium cerebelli and the ventral dura mater. Electron microscopic studies reveal that NPY-LI is exclusively located in unmyelinated axons of small and large nerve fiber bundles, with or without a perineural sheath. Immunopositive C-fibers are predominantly associated with the vascular bed. SP-LI nerve fibers have a moderate and more uniform distribution in the encephalic dura mater. A distinct plexus of SP-LI fibers follows the branches of the middle meningeal artery and the adjacent dura mater. SP-LI fibers are most prominent in the parietal dura mater of the cerebellum. Fine beaded SP-LI fibers, arising from larger SP-LI fiber bundles, are observed in close association to the capillary bed. SP-LI axons are all unmyelinated. They are found in larger nerve fiber bundles with a perineural sheath or in Schwann cells lacking any perineural sheath. The function of NPY-LI and SP-LI nerve fibers in the rat dura mater is discussed in relation to their topography, density and termination.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02433496
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  • 12
    Electronic Resource
    Electronic Resource
    Myopathy with altered mitochondria due to a triosephosphate isomerase (TPI) deficiency (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 387-394 
    Details
    ISSN: 1432-0533
    Keywords: Triosephophosphate isomerase (TPI) ; Mitochondrial myopathy ; Muscle tissue ; Electron microscopy ; Enzyme histochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Morphological changes are shown in the muscle biopsy specimens of an 8-year-old girl who suffered from a triosephosphate isomerase (TPI) deficiency, resulting in a chronic, nonspherocytic, hemolytic anemia, mental retardation and neuromuscular impairment. The newly introduced enzyme histochemical reaction for TPI demonstrated a total lack of histochemically detectable enzyme activity, whereas biochemical analysis of muscle tissue revealed less than 10% of the normal enzyme activity. Electron microscopy showed a degenerative myopathy with an increase in the amount of intracellular glycogen. Additionally, mitochondrial changes within the muscle fibers were observed to be similar to those in mitochondrial myopathies. The disturbed balance between glycerinaldehyde phosphate and dihydroxy-acetone phosphate, due to the deficiency of the TPI enzyme, is interpreted as the biochemical background of an impaired electron transport across the mitochondrial membrane, resulting in the coexistence of an impaired glycolytic pathway and an impaired mitochondrial metabolism of muscle cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308714
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  • 13
    Electronic Resource
    Electronic Resource
    Myopathy in Marinesco-Sjögren syndrome: an ultrastructural study (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 123-128 
    Details
    ISSN: 1432-0533
    Keywords: Marinesco-Sjögren syndrome ; Muscle biopsy ; Electron microscopy ; Autophagocytosis ; Double-membrane structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven muscle biopsies from patients with the clinical characteristics of Marinesco-Sjögren syndrome (MSS) revealed myopathic changes of two types; muscle fiber necrosis followed by regeneration and focal myofibrillar degeneration inducing autophagocytosis with rimmed vacuole formation. In two young patients, massive muscle fiber necrosis with phagocytic invasion was the predominant feature and autophagic phenomenon was minimal, resembling the findings in progressive muscular dystrophy. Myofibrillar degeneration with autophagic phenomenon was prominent in five adult patients. The coexistence of these two degenerative processes and the secondarily induced reactive changes of muscle fiber hypertrophy, interstitial fibrosis, occasional ragged-red fibers and type 1 fiber predominance, are responsible for the wide spectrum of muscle pathology in MSS. The dense double-membrane structure surrounding myonuclei, previously reported as being specific to MSS, was present in only one biopsy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308914
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  • 14
    Electronic Resource
    Electronic Resource
    Histological changes of neuronal damage in vegetative dogs induced by 18 minutes of complete global brain ischemia: two-phase damage of Purkinje cells and hippocampal CA1 pyramidal cells (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 527-534 
    Details
    ISSN: 1432-0533
    Keywords: Global ischemia ; Cerebellum ; Hippocampus ; Electron microscopy ; Synapse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have developed a functional vegetative model by an 18-min clamping of the ascending aorta combined with a bypass formation between the aorta to right atrium and the aorta to femoral vein. Complete global brain ischemia (CGBI) induced for 18 min with this model provided the following distinct advantages: cardiopulmonary functions were well preserved during postischemic recirculation, and all dogs survived without serious extracerebral complications. Neuronal damage in vegetative dog induced by an 18-min CGBI was studied by light and electron microscopy. The Purkinje cells and the hippocampal CA1 pyramidal cells showing clumping of nuclear chromatin and slightly increased stainability were observed after CGBI without recirculation. All these neurons showed transient increased stainability with microvacuolation 15 min after recirculation. Over 50% of these neurons showed virtually normal features 1 h after recirculation. Damage to these neurons progressed again slowly up to 6 h after recirculation. However, all these neurons had disintegrated 2–3 days after recirculation. A decrease in synaptic vesicles was observed in many presynaptic terminals in the molecular layers of the cerebellum after CGBI without recirculation. These changes in the presynaptic terminals progressed 15 min after recirculation. These results indicated that the damage to the Purkinje cells and the CA1 pyramidal cells induced by CGBI consisted of two phases, and that the change in the early phase was reversible. We speculate that the damage to the Purkinje cells in the early stage is related to the decrease of the synaptic vesicles in the presynaptic terminals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294614
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  • 15
    Electronic Resource
    Electronic Resource
    An immunocytochemical study of protein clearance in brain infusion edema (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 162-177 
    Details
    ISSN: 1432-0533
    Keywords: Infusion edema ; Immunocytochemistry ; Clearance ; Electron microscopy ; Brain edema
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathways and mechanisms by which edematous fluid accumulation in the extracellular space (ECS) clears from brain are poorly understood. The objective of this study was to explore, using immunocytochemical technique, the fate of a proteinaceous fluid added to the brain ECS and to study the clearance pathways. The protein movement of this edema fluid was investigated using the direct infusion model on rats. Rat albumin (20 μl) was slowly infused into the caudate-putamen of anesthetized adult rats and the spread and clearance of the edema was followed in various brain regions using immunocytochemical and conventional light and electron microscopy at 0, 1, 2, 3, 4, 6, and 8 days post-infusion. Our studies showed that protein-rich edema fluid cleared slowly from the brain, with 8 days required for the infusion albumin to exit completely from the brain parenchyma. Immediately following infusion, the albumin was distributed in the ECS of the white matter and the overlying deep cortical layers related to the infusion site. During the next 24 h, more of the infused albumin traveled through the ECS to the cortical surface where the albumin passed through the glia limitans to reach the subarachnoid front. Additionally, at 48 h post-infusion, that albumin, which had migrated to the ventricular wall, cleared from the ECS of the subependymal white matter and the ependymal clefts to reach the ventricular cerebrospinal fluid (CSF). In edematous regions, the perivascular spaces of venules and veins were filled with reaction product. Continuity of this perivascular reaction product existed from the deep edematous area to the temporobasal subarachnoid space from where the reaction product gradually disappeared from the parenchyma. From these studies we infer that during the late state of the resolution process the edema front moves toward both the ventricle and the cortical surface to reach the CSF. Thus, among the potential routes for edema clearance, the pathways leading to CSF clearance of fluid predominated. During this clearance process, neither neurons, glia nor the vascular endothelium showed any endocytotic response to the infused albumin throughout the 8-day course. We conclude from these observations that the CSF pathway is the major route of protein-rich edema clearance, when such clearance is not complicated by any concomitant CNS perturbation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334505
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  • 16
    Electronic Resource
    Electronic Resource
    An immunoelectron microscopic study of corticotrophs in the golden hamster (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 539-545 
    Details
    ISSN: 1432-0568
    Keywords: Corticotrophs ; Pituitary gland ; Golden hamster ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructure of corticotrophs in the pituitary of golden hamsters was studied by immunocytochemistry. Corticotrophs were classified into three types according to the different size of the secretory granules. Type A and B cells were oval or polygonal in shape containing small (158±38 nm) and medium-sized (250±53 nm) secretory granules, respectively. Type C cells were usually pyramidal or irregular in shape, and contained large secretory granules (380±78 nm). The cytoplasmic organelles of type B and C cells were fairly well developed. In all types of corticotrophs, the secretory granules varied in electron density, and were either arranged in a single row along the cell membrane, or concentrated in the vascular pole of the cytoplasm. Many of the corticotrophs sent processes to encircle neighboring somatotrophs. In the female, the proportions of type A and B cells were higher then those in the male, whereas that of the type C cells was lower. All three types of corticotrophs were observed in the early postnatal stage. The population of type A cells decreased with the advancement of postnatal development, with a concomitant increase of that of the type C cells. Thus, type A cells might represent the immature type of corticotrophs which would evolve to become the type C cells. One to 2 weeks after adrenalectomy, the number of type C cells was drastically increased. This was accompanied by their prominent changes in ultrastructure as in the type B cells. The cytoplasm became hypertrophic with extensive dilated cisternae of rough endoplasmic reticulum. The large Golgi apparatus displayed profiles seemingly involved in the formation of secretory granules. The number of type A cells was moderately decreased, and they showed little morphological alteration. Since type B and C corticotrophs exhibited a remarkable response to adrenalectomy, it is concluded that they represent the active state of corticotrophs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00186460
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  • 17
    Electronic Resource
    Electronic Resource
    Patterns of differentiation in central neurocytoma (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 473-479 
    Details
    ISSN: 1432-0533
    Keywords: Central neurocytoma ; Neuronal differentiation ; Glial differentiation ; Synaptophysin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Central neurocytoma has been characterised by its intraventricular localisation, predominant occurrence in young adults, oligodendroglioma-like histology, benign course and ultrastructural evidence for neuronal differentiation. Eleven intraventricular central neurocytomas were studied histopathologically, employing cell type-specific immunocytochemical markers and electron microscopic analysis. In the past, these lesions have caused diagnostic problems since central neurocytomas share basic histopathological features with other periventricular neoplasms. Accordingly, several tumours of this series had previously been classified as ependymomas of the foramen of Monro or oligodendrogliomas. Although generally regarded as benign lesions, two central neurocytomas of this series showed histopathological evidence of anaplasia, with focal necrosis, mitotic activity and vascular proliferation. All central neurocytomas exhibited immunoreactivity for neuronspecific enolase and synaptophysin, indicating consistent neuronal differentiation. Three tumours were studied by electron microscopy and contained synaptic vesicles, neuritic processes and neurosecretory granules. In addition, one tumour contained ganglioid cells and this was associated with focal immunoreactivity for neurofilament protein, suggesting that some central neurocytomas may, at least focally, continue to differentiate towards the formation of mature neurons. Two of the tumours expressed glial fibrillary acidic protein in a considerable percentage of neoplastic cells which demonstrates a capacity for bipotential, i.e. glial and neuronal differentiation. We conclude that the central neurocytoma can be reliably diagnosed using antibodies to neuron-specific enolase and synaptophysin, and that histogenetically, this neoplasm is derived from a neuroectodermal precursor cell capable of both, neuronal and glial differentiation. The hypothesis is proposed that the central neurocytoma originates from the subependymal plate of the lateral ventricles, an embryonal matrix cell layer which postnatally maintains a limited proliferative potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00296105
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  • 18
    Electronic Resource
    Electronic Resource
    Polar spongioblastoma: an immunohistochemical and electron microscopical study (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 228-232 
    Details
    ISSN: 1432-0533
    Keywords: Cerebral tumor ; Polar spongioblastoma ; Astrocytoma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is reported of a 9-year-old boy with a cerebral polar spongioblastoma. This neoplasm, first described by Russell and Cairns in 1947, is morphologically a distinct entity characterized by bipolar tumor cells with palisading nuclei. In the case under study immunoreactivity for neuron-specific enolase was found and ultrastructural features of developing neuronal elements were present. A neuro-endocrine nature was suggested by de Chadarévian et al. (1984) in a morphologically similar case. These findings are in contrast with the longheld view that the polar spongioblastoma is cytogenetically related to the embryonal radial glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334514
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  • 19
    Electronic Resource
    Electronic Resource
    Appearance of tubulovesicular structures in experimental Creutzfeldt-Jakob disease and scrapie preceeds the onset of clinical disease (1990)
    Springer
    Acta neuropathologica 79 (1990), S. 349-354 
    Details
    ISSN: 1432-0533
    Keywords: Creutzfeldt-Jakob disease ; Electron microscopy ; Scrapie ; Tubulovesicular structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have consistently observed tubulovesicular structures in brain tissues during the terminal stages of naturally occurring and experimentally induced spongiform encephalopathies, irrespective of the host species and virus strain. In NIH Swiss mice inoculated intracerebrally or intraocularly with the Fujisaki strain of Creutzfeldt-Jakob disease (CJD) virus, tubulovesicular structures, measuring 20–50 nm in diameter, were particularly prominent in dilated, pre-and postsynaptic neuronal processes, occasionally being mixed with synaptic vesicles. These structures appeared 13 weeks following intracerebral inoculation, 5 weeks before the onset of clinical signs, when spongiform changes were also detected. The number and density of tubulovesicular structures increased steadily during the course of clinical disease, and were particularly abundant in mice 47 to 51 weeks after intraocular inoculation. In hamsters infected with the 263 K strain of scrapie virus, these structures were initially detected 3 weeks following intracerebral inoculation and increased dramatically at 10 weeks postinoculation. The appearance of tubulovesicular structures before the onset of overt disease in mice inoculated with CJD virus by either the intracerebral or intraocular route, and before the appearance of other neuropathological changes in hamsters infected with scrapie virus, indicate that they represent either a part or aggregate of the infectious virus or a pathological product of the infection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00308710
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  • 20
    Electronic Resource
    Electronic Resource
    Ultrastructural and biochemical findings in brain cell cultures infected with canine distemper virus (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 59-67 
    Details
    ISSN: 1432-0533
    Keywords: Brain cell culture ; Canine distemper virus ; Cerebroside sulfotransferase ; Electron microscopy ; Oligodendrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the pathomechanism of demyelination in canine distemper (CD), dog brain cell cultures were infected with virulent A75/17-CD virus (CDV) and examined ultrastructurally. Special attention was paid to the oligodendrocytes, which were specifically immunolabelled. In addition, cerebroside sulfotransferase (CST), an enzyme specific for oligodendrocyte activity was assayed during the course of the infection. Infection and maturation as well as CDV-induced changes were found in astrocytes and brain macrophages. Infection of oligodendrocytes was rarely seen, although CST activity of the culture markedly decreased and vacuolar degeneration of these cells occurred, resulting in their complete disappearance. We concluded that the degeneration of oligodendrocytes and demyelination is not due to direct virus-oligodendrocyte interaction, but due to CDV-induced events in other glial cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294222
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  • 21
    Electronic Resource
    Electronic Resource
    A case of cerebral composite ganglioneuroblastoma: an immunohistochemical and ultrastructural study (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 98-102 
    Details
    ISSN: 1432-0533
    Keywords: Composite ganglioneuroblastoma ; Electron microscopy ; Cerebrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An unusual cerebral tumor is reported in a 14-year-old boy. On light and electron microscopy, the constituent cells were very complex; the majority of the neoplastic cells were primitive neuroectodermal cells dispersed in myxomatous or fibrous stroma. Neoplastic neuronal cells and hypertrophic astrocytes were also observed in these areas. The neuronal cells showed a continuous spectrum of differentiation from very primitive to mature ganglion cells. Furthermore, the tumor contained a highly cellular discrete area consisting of neuroblasts and their precursor cells. From these findings, a diagnosis of composite ganglioneuroblastoma was made.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294230
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  • 22
    Electronic Resource
    Electronic Resource
    Cerebral medulloepithelioma — electron microscopy and immunohistochemistry (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 103-107 
    Details
    ISSN: 1432-0533
    Keywords: Brain neoplasms ; Medulloepithelioma ; Primitive neuro-ectodermal tumor ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case is reported of a boy, 3 years of age, with a large medulloepithelioma in the left cerebral hemisphere. Medulloepitheliomas are rare tumors of the primitive medullar epithelium. Histological, immunohistochemical and electron microscopical findings are presented. We discuss previously reported cases, the ontogeny of this type of tumor and the relation to the socalled primitive neuro-ectodermal tumors (PNET).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00294231
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  • 23
    Electronic Resource
    Electronic Resource
    An autopsy case of peroneal muscular atrophy with rigidity and tremor (1990)
    Springer
    Acta neuropathologica 80 (1990), S. 671-679 
    Details
    ISSN: 1432-0533
    Keywords: Peroneal muscular atrophy ; Rigidity and tremor ; Autopsy ; Morphometry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An autopsy case of hereditary peroneal muscular atrophy (PMA) with rigidity and static tremor is presented. The patient developed slowly progressive distal muscular atrophy of the legs at the age of 15 years. By the age of 52 years, PMA became marked associated with pes cavus, and tremor and rigidity of the extremities were noted. Motor and sensory conduction velocities gradually depressed and lost near the end of his life. At autopsy, the major neuropathological abnormalities involved the peripheral nervous systems, and were characterized by axonal atrophy and loss of myelinated fibres. These changes involved both the proximal and distal nerves, being more severely affected in the distal. The pathological changes in other regions of the nervous systems were mainly confined to the spinal cord, dorsal ganglia and spinal nerve roots, and pigmented neurons in the brain stem. Morphometrically, the total fascicular area was much smaller than in control, but the total number of myelinated fibers greatly outnumbered that of control 75 200 to 48 200 at the proximal sciatic nerve and then gradually decreased towards the periphery; however, even in the distal sural nerve, the total number of myelinated fibers exceeded that of control (6820 to 5469). Thus, the density of myelinated fibers were much higher, being 1.5 to 2 times greater, than in control. Its abrupt decline at the distal nerve might account for neurogenic atrophy of the distal musculature. Unmyelinated fibers were slightly increased in density and not atrophic. This case is unique in its clinicopathology and does not belong to any subtypes of PMA including “neuronal plus”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00307638
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  • 24
    Electronic Resource
    Electronic Resource
    Demyelination and remyelination in spinal cord lesions of human lymphotropic virus type I-associated myelopathy (1990)
    Springer
    Acta neuropathologica 81 (1990), S. 78-83 
    Details
    ISSN: 1432-0533
    Keywords: HTLV-I-associated myelopathy ; Spinal cord lesion ; Electron microscopy ; Primary demyelination ; Remyelination by oligodendrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We describe postmortem findings in a patient with human T lymphotropic virus type I (HTLV-I)-as-sociated myelopathy (HAM). The patient developed the disease 8 years after blood transfusion and showed good response to corticosteroid treatment but died of cardiac failure. Histologically, chronic, mild meningoence-phalomyelitis was noted predominantly involving the bilateral lateral and anterior columns of the middle to lower thoracic segments. The spinal cord lesions showed obvious loss of myelinated nerve fibers and fibrillary gliosis with minimal inflammatory cell infiltration. Electron microscopy of the lesion revealed disintegration of the myelin sheaths, regular separation of the minor dense line of the myelin sheaths, and completely demyelinated axons. In addition, remyelinated fibers with thin central myelin sheaths and disproportionately large axons were seen frequently. These findings indicate that primary demyelination and remyelination by oligodendrocytes occur in the spinal cord lesions of HAM.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00662641
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  • 25
    Electronic Resource
    Electronic Resource
    Ultrastructure, protein synthesis and secretion of day-6 rabbit blastocysts cultured in a chemically defined, protein-free medium (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 465-472 
    Details
    ISSN: 1432-0568
    Keywords: In vitro culture ; Electron microscopy ; Fluorography ; Blastocyst ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Day-6 rabbit blastocysts were cultured in Ham's F10 medium supplemented with polyvinylpyrrolidone as a macromolecular component, for 4 to 12 h. The integrity of the blastocyst cells was demonstrated by electron microscopy. Expansion and biosynthesis of proteins and of DNA were studied after culturing in the presence of 35S-methionine and 3H-thymidine. Polyvinylpyrrolidone did not interfere with the subsequent protein analysis, which was performed by two dimensional gel electrophoresis followed by silver staining and fluorography. More than 600 labelled proteins were found in the blastocyst tissue, many of them were also present in the blastocyst fluid and in the blastocyst coverings. Several proteins seemed to be produced for incorporation into the blastocyst coverings; others, only detected in the culture medium, might have been synthesized for secretion into the environment.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178911
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  • 26
    Electronic Resource
    Electronic Resource
    Immunocytochemical localization of CR3 complement receptors with OX-42 in amoeboid microglia in postnatal rats (1990)
    Springer
    Anatomy and embryology 182 (1990), S. 481-486 
    Details
    ISSN: 1432-0568
    Keywords: Immunocytochemistry ; Electron microscopy ; CR3 receptors ; Amoeboid microglia ; Rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study described the labelling of amoeboid microglial cells in the postnatal rat brain with OX-42, an antibody that recognizes type 3 complement receptors CR3 in mononuclear phagocytes. Of the diverse morphological forms of amoeboid microglia present in the corpus callosum in early postnatal (2–5 days) rats, cells with a round regular outline, or showing short stout processes, were the most intensely stained. When traced from the main cell colony into the borderline zone with the cortex, the immunoreactivity of amoeboid microglia that assumed a ramified form was drastically reduced. Examination of materials from the late postnatal (8–12 days) age group showed that the majority of the OX-42 positive cells in the corpus callosum became oval, elongated and ramified. Immunoelectron microscopy confirmed the above observations, and also showed that the immunoreactivity in the round amoeboid microglia was localized in their plasma membrane, surface projections and invaginations, as well as in some of the subsurface vacuoles. The immunoreactivity was reduced in the oval cells, and diminished in the elongated or ramified form. It is proposed that the presence of CR3 membrane receptors in amoeboid microglial cells is related to their active role in endocytosis. These, however, diminish with the growth of the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178913
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  • 27
    Electronic Resource
    Electronic Resource
    Distribution and characteristics of the different astroglial cell types in the adult lizard (Lacerta lepida) spinal cord (1990)
    Springer
    Anatomy and embryology 181 (1990), S. 567-575 
    Details
    ISSN: 1432-0568
    Keywords: Astrocyte ; Radial astrocyte ; GFAP ; Electron microscopy ; Phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The astroglial cells have been studied in the lizard spinal cord by means of metallic impregnations, immunohistochemical (glial fibrillary acidic protein) and ultrastructural methods. Three astroglial cell types have been immunohistochemically identified: ependymocytes, radial astrocytes and astrocytes. Transitional forms have also been observed. Scarce immunopositive ependymocytes were located in the dorsal and ventral regions of the ependyma. The radial astrocytic somata were located around the ependymal layer and their processes reached the subpial glia limitans. Typical astrocytes were the most abundant astroglial cell type; astrocytes located in the ventral horn showed a greater development than those of the dorsal horn. In the white matter, the astrocytes were large and their processes formed part of the subpial glia limitans; on some occasions, astrocytic cell bodies also formed part of this subpial limitans. Transitional elements between astrocytes and radial astrocytes were observed in both grey and white matter. The perivascular and subpial glia limitans were continuous and showed a strong immunoreactivity. The comparative analysis of our results in the lizard spinal cord with those in other vertebrate groups leads us to conclude that reptiles could represent the key group in the phylogenetic evolution of the astroglial cells in vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174628
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  • 28
    Electronic Resource
    Electronic Resource
    Hereditary palmoplantar keratosis of the Gamborg Nielsen type (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 363-370 
    Details
    ISSN: 1432-069X
    Keywords: Autosomal recessive palmoplantar keratosis ; Electron microscopy ; Keratinization ; Keratohyalin ; Keratohyaline proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A new kind of diffuse palmoplantar keratoderma with autosomal recessive inheritance and without associated symptoms was described in Norrbotten, Sweden by Gamborg Nielsen in 1985. Clinically, it ranges between the less severe dominant Unna-Thost type and the more severe recessive Meleda type, as it is milder than the latter. Skin biopsies of five patients from three different families with this new palmoplantar keratoderma, as well as five obligatory heterozygotes from one family, were investigated ultrastructurally in order to characterize this new entity and to differentiate it from the Meleda type. Several features are common to both autosomal recessive palmoplantar keratoses. They show a broadened granular layer, a transit region consisting of cells with a marginal envelope, and considerable hyperkeratosis. Morphologically, this transformation delay is less pronounced in the Gamborg Nielsen type than in the classical Meleda type. As is typical for ridged skin, both types of palmoplantar keratoses possess composite keratohyaline granules. In contrast to the normal appearance of keratohyaline granules in the Meleda type, the Gamborg Nielsen type also shows qualitative deviations of keratohyaline granules with different degrees of spongiosity and electron density and sometimes with a granular border. It seems that abnormal keratohyaline proteins are synthesized that behave differently. The sudden transformation of a granular into a horny cell is physiologically regulated by different enzymes. A delay in this process may be caused by a mutation that reduces or alters the enzymes concerned. We assume the palmoplantar keratoderma of the Gamborg Nielsen type to be a variant of the heterogeneous group of the Meleda type of palmoplantar keratoderma with autosomal recessive inheritance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372085
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  • 29
    Electronic Resource
    Electronic Resource
    Electron microscopic study of cultured cells from the murine hair tissues: cell growth and differentiation (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 402-407 
    Details
    ISSN: 1432-069X
    Keywords: Electron microscopy ; Culture ; Hair cells ; Growth ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cultured hair cells from 4-day-old C3H mice were studied by electron microscopy. The hair roots isolated from the skin by collagenase digestion were dispersed into a cell suspension by treatment with a mixture of trypsin and ethylenediaminetetraacetate. The cells were cultured in MCDB-153 (a medium containing seven growth factors) for 1, 3, 6 or 13 days. The number of cultured cells on day 3 was twice that on day 1, and stayed at the same level until day 13. By electron microscopy, some of the cells cultured for 1 day were seen to be undifferentiated and others already showed differentiation into various hair structures. Such differentiated cells disappeared on day 3 and most of the cells cultured for 3 days were undifferentiated. Cells cultured for 6 days were differentiated showing inner root sheath cell, hair cortical cell and medulla cell structures. The characteristics of these cultured cells corresponded well to those of in vivo cells of the hair tissues from the back skin of 7-day-old C3H mice. On day 13 degeneration occurred in the cultured cells. In none of these cultures were mesenchymal cells, such as fibroblasts, found. The present electron microscopic study reveals that immature cells obtained from mouse hair tissues proliferate in vitro and differentiate into several subpopulations corresponding to those of in vivo cell layers of hair tissues. The present culture technique may be useful for studies of hair cell growth and differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372092
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  • 30
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of keratin and α-l-fucose in human eccrine sweat glands (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 12-16 
    Details
    ISSN: 1432-069X
    Keywords: Immunogold ; Electron microscopy ; Eccrine sweat glands ; Keratin ; Fucose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Human eccrine sweat glands were embedded in Lowicryl K4M. Cytokeratin proteins and blood group H antigen were localized by applying a postembedding immunogold method using a monoclonal antikeratin antibody and the lectin Ulex europaeus I. The antikeratin antibody labeled intermediate filaments in the secretory coil and dermal duct. Within dark secretory cells bundles of filaments criss-crossing the cell were labeled. Within the luminal cells of the dermal duct filaments arranged parallel to the cell surface and lying in the apex of the cell were labeled, too. The association of keratin filaments with desmosomes was visualized demonstrating their subcellular connection with other cell organelles. The desmosomes themselves remained unlabeled. The lectin Ulex europaeus I is a blood group H specific lectin and binds to α-l-fucosyl-containing glycoproteins. Dark cells of the secretory coil reacted with the lectin. Here the secretory granules, the lateral cell membranes, and the microvilli membranes were labeled. The endoplasmatic reticulum, the Golgi complex, and transport vesicles were not labeled, although the glycoprotein synthesis is considered to be located in the Golgi complex. Thus, either the number of α-l-fucose molecules in the Golgi is too low to be detected by the technique employed or the determinant of blood group H antigen is released after the secretory granules and transport vesicles leave the Golgi complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00505639
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  • 31
    Electronic Resource
    Electronic Resource
    Bicomponent keratohyalin in normal human ridged skin (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 71-75 
    Details
    ISSN: 1432-069X
    Keywords: Bicomponent keratohyalin ; Ridged skin ; Keratinization ; Sweat ducts ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Up to now, bicomponent keratohyalin has only been described for rat epithelium and human intraepidermal sweat ducts and fetal nail organ cells. In normal human interductal epidermis, the keratohyalin appears homogeneous, osmiophilic and stellate in shape. Under pathological conditions, bicomponent keratohyalin has been observed in different palmoplantar keratoses and has therefore been thought to be associated with abnormal keratosis. We studied the keratinization process in normal human plantar epidermis, in which keratohyalin was found to exhibit several morphological differences as compared to that seen in non-ridged skin. The most striking feature was seen in upper granular cells, where the keratohyalin granules consisted of two components of differing electron density. The electron-dense component formed the main part of the composite granule and was found in the cytoplasm of lower and upper granular cells. The less-electron-dense component was attached to the main component and appeared in the cytoplasm of upper granular cells, forming the convex contact zone. No intranuclear osmiophilic inclusions were present. The respective electron densities of the two keratohyalin components of ridged skin were obviously different to that of the bicomponent keratohyalin granules seen in the epidermal sweat-duct cells of the same specimen. These findings indicate the presence of at least two different types of keratohyalin proteins in normal human ridged skin. They can be distinguished at the electron-microscope level and differ from the keratohyalin of human non-ridged skin as well as from bicomponent keratohyalin granules derived from human epidermal sweat-duct cells or from rat epithelium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00493461
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  • 32
    Electronic Resource
    Electronic Resource
    Altered keratin expression in ichthyosis hystrix Curth-Macklin (1990)
    Springer
    Archives of dermatological research 282 (1990), S. 227-233 
    Details
    ISSN: 1432-069X
    Keywords: Genodermatoses ; Keratinization disorders ; Fetal cytokeratins ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pathogenesis of a rare form of the ichthyotic diseases, ichthyosis hystrix Curth-Macklin, was investigated by immunohistochemistry and electron microscopy. Monoclonal antibodies (Mabs) against keratins expressed in normal basal cells (PKK2 and KA1), Mabs against keratins only present in normal fetal skin (PKK1), and Mabs against keratins 1, 2, 10, and 11 (KA5 and K8.60) were used. The Mabs reacting with normal basal cells showed an increased reaction with many cell layers. The Mab PKK1 distinctly reacted with the basal cell layer, suggesting an expression of fetal keratins. Electron microscopic study of both normal-looking and involved skin revealed the keratinization disorder characterized by tonofilament shells, perinuclear vacuoles, and binuclear keratinocytes. The results suggest that there is no prematurity of keratinization, but rather a pathological expression of specific keratin genes leading to expression of fetal keratins in this form of ichthyosis hystrix.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00371641
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  • 33
    Electronic Resource
    Electronic Resource
    Electron microscopy: A contribution to further classification of acute unclassifiable childhood leukemia (1990)
    Springer
    Annals of hematology 60 (1990), S. 291-296 
    Details
    ISSN: 1432-0584
    Keywords: Electron microscopy ; Leukemia ; Minimally differentiated leukemia ; Childhood
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural, light microscopical and immunological features of twelve cases of acute childhood leukemia are described. Nine cases were unclassifiable by light microscopy, morphology and cytochemistry, and three were difficult to classify because of a low percentage of Sudan-Black B positive blasts. By means of electron microscopy (including peroxidase cytochemistry), two main groups were seen: 1. Acute myeloid leukemia, in which could be distinguished a) a more differentiated myeloid leukemia, b) a leukemia with megakaryoblastic involvement and c) a minimally differentiated acute myeloid leukemia with granules present and 2. lymphoblastic leukemia. One case could not be classified. The first group included two possible cases of a hybrid leukemia with CD19 or CD10 positivity as well as ultrastructural peroxidase activity. We conclude that electron microscopy aids to further classification of minimally differentiated and hybrid acute leukemias.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01736231
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  • 34
    Electronic Resource
    Electronic Resource
    Catecholamine-containing axon terminals in the hypoglossal nucleus of the rat: an immuno-electronmicroscopic study (1990)
    Springer
    Experimental brain research 81 (1990), S. 167-178 
    Details
    ISSN: 1432-1106
    Keywords: Hypoglossal nucleus ; Catecholamines ; Norepinephrine ; Immunocytochemistry ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A correlative light and electron microscopic investigation was undertaken to determine the morphology and distribution of catecholamine (CA)-containing axon terminals in the hypoglossal nucleus (XII) of the rat. This was accomplished immunocytochemically with antibody to tyrosine hydroxylase (TH). The major findings in this study were the following: 1) Immunoreactive profiles were found throughout XII and included unmyelinated axons, varicosities, axon terminals and dendrites; 2) Nonsynaptic immunoreactive profiles (preterminal axons, varicosities) were more frequently observed (55.2%) than synaptic profiles (43.5%); 3) CA-containing axon terminals ending on dendrites were more numerous (71.8%) than those synapsing on somata (25.4%) or nonlabeled axon terminals (2.7%); 4) The morphology of labeled axon terminals was variable. Axodendritic terminals typically contained numerous small, round agranular vesicles, a few large dense-core vesicles and were associated with either a symmetric or no synaptic specialization, axosomatic terminals were often associated with a presynaptic membrane thickening or a symmetric synaptic specialization and contained small, round and a few elliptical-shaped vesicles, while axoaxonic synapses formed asymmetric postsynaptic specializations; and 5) CA-positive dendritic processes were identified in XII. These findings confirm the CA innervation of XII, and suggest a complex, multifunctional role for CA in controlling oro-lingual motor behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00230113
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  • 35
    Electronic Resource
    Electronic Resource
    Renal amyloidosis in juvenile chronic arthritis: evolution after chlorambucil treatment (1990)
    Springer
    Pediatric nephrology 4 (1990), S. 463-469 
    Details
    ISSN: 1432-198X
    Keywords: Juvenile chronic arthritis ; Renal amyloidosis ; Chlorambucil ; Electron microscopy ; Protein AA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Over a 22-year period, eith patients affected with severe systemic or polyarticular juvenile chronic arthritis (JCA) developed systemic amyloidosis with nephrotic syndrome. They were treated with chlorambucil over 5–192 months (mean=44 months). With treatment, an abrupt decrease in the severity of JCA was observed in six patients but two patients were chlorambucil resistant. After a mean follow-up period of 10 years from onset of renal symptoms, one chlorambucil-resistant patient died of end-stage renal failure; two patients have a persistent nephrotic syndrome; and five patients are free from proteinaria, of whom one has developed hypertension. A good correlation was observed between the response of the rheumatic disease to chlorambucil treatment and the clinical course of renal symptoms. Fourteen renal biopsies were performed in these eight patients. In all, amyloid deposits were of the AA type, which persisted on repeat biopsies. In addition, 15%–60% of glomeruli had become globally sclerotic by the second or third biopsies. At the ultrastructural level, modifications in the structure of amyloid deposits and reparative changes of the glomeruli, characterized by partial restoration of glomerular architecture, were observed in three patients with a favourable clinical course.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00869821
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  • 36
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    Electronic Resource
    The rheumatic poison: a survey of some published investigations of the immunopathogenesis of Henoch-Schönlein purpura (1990)
    Springer
    Pediatric nephrology 4 (1990), S. 533-541 
    Details
    ISSN: 1432-198X
    Keywords: Henoch-Schönlein purpura ; Pathogenesis ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Laboratory studies of the pathophysiology of Henoch-Schönlein purpura (HSP) have become more numerous in recent years with the recognition of the disease's links with the mucosal immune system in general and IgA nephropathy in particular. There are weak genetic associations with C4 null phenotypes and with HLA B35 and DR4. Studies of plasma proteins in HSP patients show an increased IgA concentration, activation of the alternative pathway of complement and consumption of factor XIII. High molecular weight (polymeric) IgA has been detected in affected individuals, which some investigators have called “immune complexes”. Many patients synthesise an IgA rheumatoid factor in the acute phase, but other autoantibodies are largely absent. In vitro studies of lymphocytes from HSP patients have demonstrated an increased number of IgA-bearing and secreting B-cells, with altered T-cell regulation of antibody synthesis. While these observations point to immune dysregulation — primarily of IgA production — as a consistent feature of acute HSP, there is as yet insufficient information available to allow a consistent theory of pathogenesis to be formulated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00869841
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  • 37
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    Electronic Resource
    The genetics of two homothallic species of the Mucoraceae (1990)
    Springer
    Sexual plant reproduction 3 (1990), S. 31-34 
    Details
    ISSN: 1432-2145
    Keywords: Mucoraceae ; Zygomycetes ; Homothallic ; Genetics ; Nutritional complementation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Auxotrophic strains of Mucor genevensis and Zygorhynchus exponens were crossed and the resulting zygospores germinated. The presence of a true sexual cycle in both species was demonstrated by the recovery of recombinant genotypes. Expected Mendelian ratios were not realized, however. The presence of selfed zygospores among those isolated makes this observation understandable. It was possible to demonstrate nutritional complementation when young mating mycelium was transferred to minimal medium and forced heterokaryons were recovered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00189949
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  • 38
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    Electronic Resource
    Medium-chain acyl CoA dehydrogenase deficiency: Electron microscopic differentiation from Reye syndrome (1990)
    Springer
    European journal of pediatrics 150 (1990), S. 111-114 
    Details
    ISSN: 1432-1076
    Keywords: Electron microscopy ; Liver ; MCAD deficiency ; Reye syndrome
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Inborn errors involving the oxidative metabolism of fatty acids may present clinically with a Reye syndrome-like picture. This case report of a patient with medium-chain acyl CoA dehydrogenase (MCAD) deficiency illustrates that electron microscopy may help to differentiate this disorder from Reye syndrome even if a liver biopsy is performed in a patient who recovered from an acute metabolic decompensation. Together with this case, a review of the few reports in the literature of pathological findings in MCAD deficiency is given. Changes uncharacteristic for Reye syndrome are a largedroplet steatosis and the presence of distinctive mitochondrial abnormalities on electron microscopy. The detection of an electron dense mitochondrial matrix and a widened space of inner mitochondrial membranes rules out Reye syndrome and is suggestive of a disorder of mitochondrial fatty acid oxidation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02072051
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  • 39
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    Electronic Resource
    Radiological “metamorphosis” in a patient with severe congenital osteogenesis imperfecta (1990)
    Springer
    European journal of pediatrics 149 (1990), S. 403-405 
    Details
    ISSN: 1432-1076
    Keywords: Osteogenesis imperfecta ; Collagen type I ; Radiology, classification ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Congenital osteogenesis imperfecta (OI) was diagnosed by ultrasound in a 31-week-old fetus, and the diagnosis confirmed after delivery by caesarean section at week 36. The baby survived the neonatal period, but failed to thrive, had recurrent respiratory infections and ultimately died at 8 months. Cultured fibroblasts synthesized both normal type I collagen and unstable type I collagen harbouring a structural defect in the α1(I) cyanogen bromide-derived peptide number 8 (CB8) region of the molecule, indicating a heterozygous dominant mutation. A+ birth, the radiological picture was that of the “thin bone”-type of congenital OI (OI type IIB/III in the Sillence classification); at the age of 12 weeks ribs and long bones had undergone a marked expansion giving a very different picture, that of the “thick bone”-type congenital OI (OI type IIA). The mechanism responsible for this change in bone structure is not known, but fractures and callus formation are unlikely to be the only factors. Caution is needed in the interpretation of radiographs of newborns with OI for prognostic or genetic purposes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02009659
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  • 40
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    Electronic Resource
    Common mechanisms in proboscis extension conditioning and visual learning revealed by genetic selection in honeybees (Apis mellifera capensis) (1990)
    Springer
    Journal of comparative physiology 166 (1990), S. 545-552 
    Details
    ISSN: 1432-1351
    Keywords: Honeybees ; Learning ; Classical conditioning ; Selection ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Four strains of the honeybee (Apis mellifera capensis), which were selected for high (N=2) or low (N=2) performance levels in classic conditioning of olfactory and mechanosensory stimuli, were examined in two instrumental visual learning tasks. Bees were trained to coloured cardboards either at the hive entrance or at the feeding station. Positive correlations were detected between olfactory/mechanosensory conditioning and visual learning. Good and poor learners from strains selected for olfactory conditioning differed significantly in their visual learning values. These strain differences reflect genetic differences in a common learning system rather than task specific differences in sensory, motor or motivational components. Parameters that were influenced by activity of the colony (duration of stay at the feeding place, time between visits) also differed among selected strains. These effects were not due to selection. Instead, they reflect a specific genetic background produced in each strain independently of selection. The results indicate that associative learning has a genetic basis which is independent of the sensory stimuli associated with reward, the learning procedure (classical conditioning or instrumental learning) or the motor patterns used to execute the learned behavior (proboscis extension, control for flight behavior, open field orientation).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00192025
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  • 41
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    Electronic Resource
    Loss of nerve fibres in the corpus callosum of progressive subcortical vascular encephalopathy (1990)
    Springer
    Journal of neurology 237 (1990), S. 39-41 
    Details
    ISSN: 1432-1459
    Keywords: Progressive subcortical vascular encephalopathy ; Electron microscopy ; Nerve fibres ; Corpus callosum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nerve fibres of the corpus callosum were studied by electron microscopy in five elderly patients with progressive subcortical vascular encephalopathy (PSVE) and compared with those in six age-matched controls. The number of nerve fibres per unit area of the corpus callosum was decreased in PSVE by 18–26%. The loss of nerve fibres in the corpus callosum can play a role in inducing the cognitive deficit of PSVE, on the basis of the loss of nerve fibres in the cerebral hemispheres.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00319666
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  • 42
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    Electronic Resource
    Light and electron microscopic examination of amyloid-rich primitive plaques: comparison with diffuse plaques (1990)
    Springer
    Journal of neurology 237 (1990), S. 88-93 
    Details
    ISSN: 1432-1459
    Keywords: Amyloid-rich primitive plaque ; Diffuse plaque ; Amyloid ; Periodic-acid methenamine silver method ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In Alzheimer-type dementia brains, numerous “amyloid-rich primitive plaques (PPs)” were observed with β-protein immunostaining and periodicacid methenamine (PAM) staining. These amyloid-rich primitive plaques were accompanied by various degrees of small argyrophilic rod-like, granular or filamentous structures. Routine and modified-PAM electron microscopy revealed many bundles and flecks consisting of amyloid fibrils scattered widely throughout the plaques. Degenerate neurites, astrocytic processes and bundles of glial fibres also participated in the formation of the plaques. The similarities and differences between these amyloid-rich primitive plaques and diffuse plaques are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00314668
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  • 43
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    Electronic Resource
    Primary intracerebral sarcoma in childhood: case report with electron-microscope study (1990)
    Springer
    Journal of neurology 237 (1990), S. 382-384 
    Details
    ISSN: 1432-1459
    Keywords: Intracerebral sarcoma ; Meningeal sarcoma ; Light microscopy ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of a primary intracerebral sarcoma is described in a 5-year-old girl. Histology and immunohistochemistry excluded the diagnosis of a leiomyosarcoma, a malignant haemangiopericytoma or a fibrosarcoma; electron-microscopical findings indicated that the origin of the sarcoma was in the pia mater.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315665
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  • 44
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    Electronic Resource
    The vascular architecture of human xenotransplanted tumors: histological, morphometrical, and ultrastructural studies (1990)
    Springer
    Journal of cancer research and clinical oncology 116 (1990), S. 517-524 
    Details
    ISSN: 1432-1335
    Keywords: Tumor vascularization ; Tumor blood flow ; Xenograft ; Nude mouse ; Vascular corrosion cast ; Ultrastructure ; Electron microscopy ; Heterogeneity ; Vessel morphology ; Morphometry ; Necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study was designed to examine the vascular system of human xenotransplanted tumors on nude mice with different complementary morphometrical and morphological methods. The vascular system shows a chaotic arrangement. There is an extreme heterogeneity in the vascular distribution and density. Large avascular regions could be identified in several non-necrotic tumors. There was no clear difference in the vascular density between the center and the periphery of the tumors, nor was there any zonal correlation for the distribution of the necrosis. With three-dimensional corrosion casts it could be demonstrated that clusters of vessels were directly beneath areas almost free of vessels. In the center, vessels often form a sinusoidal system with numerous blind ends without clearly discernible endothelial cells. Numerous irregular tumor-cell-lined sinusoids are visible next to endothelial-lined vessels with transmission electron microscopy. With scanning electron microscopy it could be demonstrated that large-calibre endotheliazed vessels were found in the direct vicinity or in the center of non-viable zones. Even large-calibre vessels have a capillary wall structure. Sometimes, a basement membrane cannot be observed at all or only incompletely. There are numerous indications of vascular discontinuities and leaks with a widespread intercellular occurrence of blood cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01613005
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  • 45
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    Electronic Resource
    The Iowa multiplex family study of schizophrenia: Linkage analyses on chromosome 5 (1990)
    Springer
    European archives of psychiatry and clinical neuroscience 239 (1990), S. 290-292 
    Details
    ISSN: 1433-8491
    Keywords: Schizophrenia ; Linkage ; Genetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We analysed six multiplex pedigrees of schizophrenia for linkage to two DNA probes mapping to the chromosome 5q11–q13 region where linkage to a gene for schizophrenia was recently reported. Analyses were conducted using three penetrance models and considering the affected state to be schizophrenia, the schizophrenia spectrum, and all psychiatric diagnoses. All analyses gave consistently negative lod scores. Although the region was not formally excluded, no evidence for linkage was found.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01735053
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  • 46
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    Electronic Resource
    Genetic data and natural history of Friedreich's disease: a study of 80 Italian patients (1990)
    Springer
    Journal of neurology 237 (1990), S. 345-351 
    Details
    ISSN: 1432-1459
    Keywords: Spinocerebellar degeneration ; Friedreich's disease ; Diagnostic criteria ; Genetics ; Natural history
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The clinical and genetic features of 80 patients with Friedreich's disease from 64 families are described. Diagnostic criteria were: no evidence of dominant inheritance, onset by the age of 20 years, progressive unremitting ataxia of limbs and gait, and absence of knee and ankle jerks. Furthermore, at least one of the following accessory signs was present: dysarthria, extensor plantar response and echocardiographic evidence of hypertrophic cardiomyopathy. Two peaks of onset age were evident at 6–9 and 12–15 years. Analysis of intrafamily variation of onset age and absence of clustering of cardiomyopathy and diabetes did not suggest genetic heterogeneity. Peripheral nerve impairment was an early finding and showed slight further progression, whereas involvement of the cerebellar and corticospinal pathways appeared later and mainly accounted for the progressive worsening of the disease.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315657
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  • 47
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    Electronic Resource
    Approximate analysis of variance of spatially autocorrelated regional data (1990)
    Springer
    Journal of classification 7 (1990), S. 53-75 
    Details
    ISSN: 1432-1343
    Keywords: Analysis of variance ; Choropleth map ; Ecology ; Genetics ; Geography ; Permutation test ; Spatial autocorrelation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Description / Table of Contents: Résumé Cet article présente une solution au problème de l'analyse de variance, pour certains cas où la variable à analyser est spatialement autocorr élée alors que le critère de classification représente des sous-régions connexes du territoire à l'étude. On sait que les méthodes classiques d'analyse de variance ne sont pas applicables dans ce type de situation puisque la condition d'indépendance des échantillons n'est pas respectée; l'autocorrélation positive réduit la variabilité intragroupe, si bien que la quantité relative de variabilité intergroupe s'en trouve artificiellement augmentée. Cette situation correspond en réalité à une vaste catégorie de problèmes en génétique des populations, en écologie et dans d'autres branches de la biologie, ainsi qu'en épidémiologie, en géographie, en géologie, en science économique, en science politique et en sociologie. Ce nouveau test appartient à la famille des tests par permutation. Nous calculons la somme des dispersions intragroupes et testons contre une distribution de référence obtenue en permutant les régions géographiques un grand nombre de fois sur la carte. La véritable difficulté de ce test est d'ordre algorithmique, puisqu'il n'est pas facile de permuter des régions sur une carte, de façon à ce que chaque groupe demeure connexe, et que la carte permutée occupe le même espace total que la carte d'origine. Cet article présente la théorie, les algorithmes, ainsi que des résultats obtenus par cette méthode. Un programme écrit en PASCAL est disponible.
    Notes: Abstract The classical method for analysis of variance of data divided in geographic regions is impaired if the data are spatially autocorrelated within regions, because the condition of independence of the observations is not met. Positive autocorrelation reduces within-group variability, thus artificially increasing the relative amount of among-group variance. Negative autocorrelation may produce the opposite effect. This difficulty can be viewed as a loss of an unknown number of degrees of freedom. Such problems can be found in population genetics, in ecology and in other branches of biology, as well as in economics, epidemiology, geography, geology, marketing, political science, and sociology. A computer-intensive method has been developed to overcome this problem in certain cases. It is based on the computation of pooled within-group sums of squares for sampled permutations of internally connected areas on a map. The paper presents the theory, the algorithms, and results obtained using this method. A computer program, written in PASCAL, is available.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01889703
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    Electronic Resource
    The Rj4 allele in soybean represses nodulation by chlorosis-inducing bradyrhizobia classified as DNA homology group II by antibiotic resistance profiles (1990)
    Springer
    Theoretical and applied genetics 80 (1990), S. 33-37 
    Details
    ISSN: 1432-2242
    Keywords: Genetics ; Symbiosis ; Nitrogen fixation ; Coevolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary To determine the relationship between nodulation restriction by the Rj4 allele of soybean, rhizobitoxine-induced chlorosis, and taxonomic grouping of bradyrhizobia, 119 bradyrhizobial isolates were tested in Leonard jar culture for nodulation response and chlorosis induction. In addition to strain USDA 61, the strain originally reported as defining the Rj4 response, eight other isolates (i.e., USDA 62, 83, 94, 238, 252, 259, 260, and 340) were discovered to elicit the nodulation interdiction of the Rj4 allele. Only 16% of all the bradyrhizobial strains tested induced chlorosis, but seven of the nine strains (78%) interdicted by the Rj4 allele were chlorosis-inducing strains. Furthermore, in tests for antibiotic resistance profile, eight of the nine interdicted strains (89%) were classed in DNA homology group II. This evidence suggests that the Rj4 allele has a positive value to the host plant in shielding it from nodulation by certain chlorosis-inducing bradyrhizobia of a DNA homology group with impaired efficiency of nitrogen fixation with soybean.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224012
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  • 49
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    Electronic Resource
    Genetical control and linkage relationships of Isozyme markers in sugar beet (B. vulgaris L.). 2. NADP- and NAD-specific malate dehydrogenases, 6-P-gluconate dehydrogenase, shikimate dehydrogenase, diaphorase and aconitase (1990)
    Springer
    Theoretical and applied genetics 80 (1990), S. 593-601 
    Details
    ISSN: 1432-2242
    Keywords: Beta vulgaris ; Sugar beet ; Isozymes ; Genetics ; Linkage ; Pollen fertility restorer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The NADP-specific malate dehydrogenase isozymes were controlled by multiple gene systems. Three genes coding for dimeric enzymes segregated in a dependent fashion (NADP-Mdh 1, NADP-Mdh 2, NADP-Mdh 3). A fourth gene (NADP-Mdh 4), also coded for dimers, but was not polymorphic in B. vulgaris. A fifth gene (NADP-Me 1) coded for enzymes active as monomers. Two genes were found to control the main zone of NAD-specific malate dehydrogenase: one coded for dimers (Mdh 1), while a second (Mdh 2) was not polymorphic in the assessions studied. 6-P-Gluconate dehydrogenase was not polymorphic in B. vulgaris; the two types detected on SGE1 electrophoresis were due to developmental expression of the different systems. No genetical segregations could be detected in progeny of crosses of the distinct phenotypes. A shikimate dehydrogenase gene (Skdh 1) that coded for monomers was identified. The diaphorase system was rather complex, but one gene (Dia 1) coding for monomeric enzymes could be identified. Aconitase was found to be controlled by two independent genes (Aco 1, Aco 2), both polymorphic and coding for proteins active as monomers. Tight linkage was found between the genes NADP-Mdh 1, NADP-Mdh 2 and NADP-Mdh 3. Linkage was also found between a pollen fertility restorer (Z) and the Mdh 1 gene. The identification of linkage with Aco 1 needs further investigation. R segregated independently from Mdh 1, Aco 1 and Dia 1. Independent segregations were scored for isozyme genes Pgm 2, Icd 1, Ak 1, Gpi 1, Aco 1 and Dia 1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00224217
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  • 50
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    Differentiation of mast cells during postnatal development of neonatally estrogen-treated rats (1990)
    Springer
    Cell & tissue research 259 (1990), S. 25-31 
    Details
    ISSN: 1432-0878
    Keywords: Testis ; Mast cells ; Estrogen ; Cytochemistry ; Electron microscopy ; Rat, Wistar
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The accumulation of mast cells in the testicular interstitium of neonatally estrogen-treated rats was studied from 15 to 90 days of age. The maturation of these cells was assessed by ultrastructural analysis and their histochemical properties were examined with the sequential alcian blue-safranin staining method. The first identifiable mast cells appeared in the testis at 17–20 days of age, as immature cells with proliferative capacity. The density of mast cells increased up to 45 days of age, showing a slight decrease from 45 to 90 days of age. Before 45 days of age, most mast cells showed alcian blue-stained granules, whereas at 45 days of age, most cells presented a mixture of alcian blue and safranin-stained granules. From this age onward, most cells were stained with safranin. These maturational changes were well-correlated with their ultrastructural features. Mast cells presented few and heterogeneous immature granules up to 45 days of age, and many uniform electron-dense granules at 90 days of age. These results indicate that the testicular interstitium of neonatally estrogen-treated rats provides an adventageous environment for the recruitment, proliferation and maturation of connective tissue mast cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571426
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  • 51
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    Electronic Resource
    Keratin filaments of epithelial and taste-bud cells in the circumvallate papillae of adult and developing mice (1990)
    Springer
    Cell & tissue research 260 (1990), S. 41-48 
    Details
    ISSN: 1432-0878
    Keywords: Keratin filament ; Circumvallate papilla ; Taste bud ; Immunocytochemistry ; Electron microscopy ; Mouse (dd)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Keratin filaments of epithelial- and taste-bud cells in the circumvallate papillae of adult and developing mice were studied by immunocytochemistry using monoclonal antikeratin antibodies (PKK2 and PKK3) and by conventional electron microscopy. Elongated cells (type-I,-II, and-III cells) of the taste buds were stained by PKK3 antibody, which reacts with 45-kdalton keratin, whereas basal cells of the taste buds and surrounding epithelial cells showed negative staining with PKK3. Such PKK3-reactive cells occurred at 0 day after birth, when taste-buds first appeared in the dorsal surface epithelium of the papillae. Thus 45-kdalton keratin seems to be an excellent immunocytochemical marker for identifying taste-bud cells. Epithelial cells in all layers of the trench wall and basal layer cells of the dorsal surface contained densely aggregated bundles of keratin filaments that reacted with PKK2 antibody, but not with PKK3. In contrast, taste-bud cells and spinous and granular layer cells of the dorsal surface possessed loose aggregated bundles of filaments that reacted with PKK3, but not with PKK2. These results suggest that the aggregation and distribution pattern of keratin filaments may reflect differences in the keratin subtypes that comprise these filaments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297488
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  • 52
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    Electronic Resource
    Crystalloid lysozyme inclusions in Paneth cells of vitamin A-deficient rats (1990)
    Springer
    Cell & tissue research 260 (1990), S. 625-628 
    Details
    ISSN: 1432-0878
    Keywords: Vitamin A-deficiency ; Paneth cells ; Crystalloid lysozyme ; Tubular structures ; Intestinal local immunity ; Electron microscopy ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of vitamin A-deficiency on jejunal Paneth cells in rats was investigated. Crystalloid particles were observed in secretion granules of Paneth cells from 6 out of 8 rats with vitamin A-deficiency. The particles were similar to those found in Paneth cells under other experimental conditions. Using an immuno-electron-microscopic technique we demonstrated a clear lysozyme immunoreactivity of these particles. In 2 vitamin A-deficient rats tubular structures have been detected in addition to the crystalloid particles. Crystalloid particles or tubular structures were not detectable in a control group of 8 vitamin A-supplemented rats. The morphological alterations of Paneth cells may be correlated to an impaired local immunity of the intestine during vitamin A-deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00297244
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  • 53
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    A freeze-etch study of angular marginal-plate-containing peroxisomes in the proximal tubules of bovine kidney (1990)
    Springer
    Cell & tissue research 260 (1990), S. 409-414 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Peroxisomes ; Marginal plates ; Electron microscopy ; Freeze-etching ; DAB-cytochemistry ; Bovine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of peroxisomes in the proximal nephron tubules of bovine kidney cortex was studied using ultrathin-sectioning, diaminobenzidine cytochemistry for the visualization of catalase, and by freeze-fracture. Peroxisomes in this nephron segment are up to 1.5 μm in diameter and exhibit a peculiar angular shape, which is probably related to the occurrence of multiple straight plate-like inclusions (marginal plates) in the matrix of peroxisomes; they lie directly underneath the peroxisomal membranes. The peroxisomal membrane in such regions follows the outline of the marginal plate. The peculiar shape of peroxisomes allows their unequivocal identification in freeze-fracture preparations. Peroxisomal membranes are recognized by their flat, often rectangular appearance. Intramembrane particles are much more numerous on P-fracture faces than on E-fracture faces. A crystalline lattice-structure with a periodicity of approximately 10 nm can be observed on the flat rectangular areas of E-fracture faces. This lattice structure is intensified after prolonged freeze-etching. Intramembranous particles seem to be superimposed over this pattern. The crystalline pattern on the E-fracture faces of peroxisomal membranes is probably not a membrane structure but it reveals the structure of the membrane-associated marginal plates. A cast of the marginal-plate surface may be generated by a collapse of the peroxisomal membrane half onto the immediately underlying matrix inclusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00318644
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  • 54
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    Intragranular co-storage of neuropeptide Y and arginine vasopressin in the paraventricular magnocellular neurons of the rat hypothalamus (1990)
    Springer
    Cell & tissue research 262 (1990), S. 47-52 
    Details
    ISSN: 1432-0878
    Keywords: Neuropeptide Y ; Arginine vasopressin ; Co-storage ; Immunohistochemistry ; Electron microscopy ; Paraventricular nucleus ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Certain populations of arginine vasopressin (AVP) neurons in the magnocellular paraventricular nucleus became immunoreactive for neuropeptide Y (NPY) when rats were treated with colchicine or monosodium glutamate (MSG). The co-storage of these peptides was examined by empooying a post-embedding electron-microscopic immunohistochemistry technique using goldlabeled antibodies to the two peptides. In colchicinetreated rats, the neuronal perikarya contained numerous secretory granules showing co-storage of the two peptides. The cells of the MSG-treated rats were characterized by having well-developed Golgi bodies with the granular structures also co-storing the two peptides, although the secretory granules in the perikarya were rather fewer than in the colchicine-treated rats. It is concluded that the destruction of the arcuate nucleus by MSG-treatment may potentiate the synthesis of NPY in AVP neurons, the synthesis of which is latent in intact animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00327744
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  • 55
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    Structural changes during the first divisions of embryos resulting from anther and free microspore culture inBrassica napus (1990)
    Springer
    Protoplasma 156 (1990), S. 149-162 
    Details
    ISSN: 1615-6102
    Keywords: Anther embryogenesis ; Brassica napus ; Electron microscopy ; Histochemistry ; Microspore embryogenesis ; Pollen division
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Ultrastructural and cytochemical features of embryo development during anther and free microspore culture inBrassica napus have been followed from the late uninucleate microspore stage through the first embryonic division. On transfer to culture, the microspore cytoplasm possesses a large vacuole, often containing electron opaque aggregates, and a peripheral nucleus. Mitochondria, endoplasmic reticulum and starch-free plastids are distributed throughout the cytoplasm. The conditions of culture induce a number of major changes in the cytoplasmic organisation of the microspore. First, the central vacuole becomes fragmented allowing the nucleus to assume a central position within the cell. Secondly, starch synthesis commences in the plastids which, in turn, are seen to occupy a domain investing the nucleus. Thirdly, the cell develops a thick fibrillar wall, situated immediately adjacent to the intine of the immature pollen wall. Finally, the microspores develop large cytoplasmic aggregates of globular material. The nature of this substance remains unknown, but it remains present until the young embryos have reached the 30 cell stage. The first division of cultured microspores destined to become embryos is generally symmetrical, in contrast to the asymmetric division seen in normal development in vivo. Consideration is given to the differences observed between embryos developing from anthers and free microspores in culture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01560653
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  • 56
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    Electronic Resource
    Localization of acid phosphatase in lactating rat mammary glands (1990)
    Springer
    Protoplasma 153 (1990), S. 149-156 
    Details
    ISSN: 1615-6102
    Keywords: Acid phosphatase ; Electron microscopy ; Mammary glands ; Subcellular fractions ; Substrate specificity ; Sulfhydryl agents ; Tartrate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Localization of acid phosphatase in mammary glands of lactating rats was studied by both biochemical and cytochemical methods. Cytochemically, acid phosphatase activity was detected by using lead citrate as the capture agent for the inorganic phosphate released from p-nitrophenyl phosphate. The activity was predominantly localized in the lumina of the endomembrane system and in the milk that had been secreted into the alveolar lumen. Biochemically, acid phosphatase was present in all the subcellular fractions with higher activities in the membrane-associated fractions. The localization of tartrate-resistant acid phosphatases within the endomembrane system of fully lactating rat mammary tissue suggests a possible role for these enzymes in milk secretory processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01353999
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    Tubulin conformation in microtubule-free cells ofVigna sinensis (1990)
    Springer
    Protoplasma 154 (1990), S. 132-143 
    Details
    ISSN: 1615-6102
    Keywords: Vigna sinensis ; Immunofluorescence ; Electron microscopy ; Colchicine ; Tubulin reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The primary leaf, epicotyl, and root cells ofVigna sinensis seedlings grown continuously in a 0.08% colchicine solution, become microtubule-free and polyploid. In meristematic root cells a tubulin transformation is detected 1–3 h after the treatment had begun. Tubulin strands are organized at the positions of the pre-existing microtubules. Frequently, the strands converge on or are organized in the cortical cytoplasmic zone where in normal cells the preprophase microtubule band (PMB) is assembled. In meristematic root cells subjected to a 6–12 h colchicine treatment, the tubulin strands become perinuclear, entering the cortical cytoplasm at regions close to the nucleus. One day after the onset of the treatment, tubulin generally forms a continuous reticulum of interconnected strands in all the organs examined. In most cells this reticulum surrounds the nucleus partly or totally or lies close to it, exhibiting variable configurations in different cells. After prolonged treatments, the organization of the tubulin reticulum changes further. Now this consists of crystal-like structures interconnected by thin strands. On thin sections of fixed tissue the tubulin strands consist of paracrystalline material. The distribution of this material in the affected cells coincides with that of tubulin reticulum visualized by immunofluorescence. In transverse planes each strand exhibits circular subunits arranged close to one another in a hexagonal pattern but in longitudinal ones variable images were observed. The paracrystalline material persists in root cells subjected to an 8-day continuous colchicine treatment. The immunolabeled strands seem to be composed of tubulin-colchicine complexes and not pure tubulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01539840
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    Are genes units of inheritance? (1990)
    Springer
    Biology and philosophy 5 (1990), S. 349-371 
    Details
    ISSN: 1572-8404
    Keywords: Genetics ; gene structure ; hereditary unit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Definitions of the term ‘gene’ typically superimpose molecular genetics onto Mendelism. What emerges are persistent attempts to regard the gene as a ‘unit’ of structure and/or function, language that creates multiple meanings for the term and fails to acknowledge the diversity of gene architecture. I argue that coherence at the molecular level requires abandonment of the classical unit concept and recognition that a gene is constructed from an assemblage of domains. Hence, a domain set (1) conforms more closely to empirical evidence for genetic organization of DNA regions capable of transcription and (2) has ontological properties lacking in the traditional unit definition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00165258
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  • 59
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    The importance of sampling scale in the assessment of intraspecific life-history differences in plains killifish, Fundulus zebrinus, populations (Pisces: Cyprinodontidae) (1990)
    Springer
    Environmental biology of fishes 29 (1990), S. 263-275 
    Details
    ISSN: 1573-5133
    Keywords: Demography ; Genetics ; Geographic variation ; Stochasticity ; Fluctuating environments ; Allele frequencies ; River ecology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis The purpose of this study was to determine the effects of unpredictable environmental fluctuations on the demographic and genetic structure of Fundulus zebrinus populations. Collections of F. zebrinus were taken from three rivers in the Arkansas River basin: the Arkansas, Chikaskia, and Ninnescah. Fish were sampled from three sites on each river on nine collection dates throughout 1984 and 1985. Totals of 2100 fish and 6000 fish were included in electrophoretic and demographic analyses, respectively. The results of the study indicate that within a limited geographic region (i.e. within rivers) spatial differences and temporal changes in both demographic and genetic population characteristics occur frequently and are primarily stochastic. However, on a larger spatial scale (i.e. across rivers), general trends emerge for demographic and especially for genetic population characteristics. These results illustrate the importance of sampling scale for conclusions of life-history evolution in fluctuating environments. In addition, it was found that regulation of Fundulus zebrinus populations includes an important density-independent component. Stochastic demographic differences across space and changes through time and spatially and temporally heterogeneous allele frequencies, are both indicative of density-independent regulation. Variation in population parameters, both demographic and genetic, was observed between populations sampled from each river. These population differences were attributed to differences between the rivers themselves.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00001184
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    Genetic aspects of interpopulational differences in pheromone blend of cabbage looper moth,Trichoplusia ni (1990)
    Springer
    Journal of chemical ecology 16 (1990), S. 2935-2946 
    Details
    ISSN: 1573-1561
    Keywords: Genetics ; sex pheromone ; Lepidoptera ; Noctuidae ; Trichoplusia ni ; cabbage looper moth ; reproductive isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The genetic basis of interpopulational differences in the pheromone blend emitted by the cabbage looper moth,Trichoplusia ni (Hübner), was examined by crossing individuals from a field-derived population (P1) with individuals from a long-maintained laboratory colony (P2). These colonies differed in the emission rate and relative proportions of four of the five known minor pheromone components, but not in the emission rate of the major component, (Z)-7-dodecenyl acetate (Z7-12∶Ac). These differences in pheromone blend were quantitatively small but biologically significant, because in the field, males responded preferentially to traps baited with a pheromone blend that is similar to that emitted by P1 females relative to a blend similar to that emitted by P2 females. In initial crosses, variation in the quantity and quality of pheromone blends among families of P1, P2, and F1 hybrid females was examined. In F1 females the relative proportions (quantity relative to the major component) of (Z)-5-dodecenyl acetate (Z5-12∶Ac) and (Z)-7-tetradecenyl acetate (Z7-14∶Ac) were intermediate to parental lines. In a second more extensive set of crosses, analyses included P1, P2, F1, F2, and selected backcrosses. The relative proportion of Z5-12∶Ac, Z7-14∶Ac, and Z9-14∶Ac emitted by F1 females were intermediate to parental lines. The frequency distributions of relative proportions of these components emitted by females were not consistent with those expected under a single autosomal or sex-linked gene hypothesis, suggesting that more than one gene is involved in the quantitative differences in the pheromone blend.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00979485
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    Lipofuscin pigments in the spiral ganglion of the rat (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 189-193 
    Details
    ISSN: 1434-4726
    Keywords: Spiral ganglion ; Lipofuscin ; Ceroid ; Vitamin E deficiency ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to clarify morphological differences in lipofuscin or so-called age pigments observed in the spiral ganglion cells of both young and adult rat groups and to characterize the size and structure of ceroid pigment granules generated in vitamin-E-deficient rats. The results showed different patterns of lipofuscin distribution in the two groups. The adult rat group had large aggregated lipoid, dark pigment granules of irregular shape in the cytoplasm. In contrast, the young group had small numbers of small, dense homogeneous granules, suggesting higher Schwann cell phagocytic activity. The ceroid pigments apparently included numerous vesicles and droplets of more variable density and size than the lipofuscin pigments appearing in the non-treated older animals. Both lipofuscin and ceroid pigments developing in such non-dividing cells are produced as a result of peroxidation reactions, so that the more they accumulate in the cytoplasm the more likely cell function deteriorates. The present study has shown that lipofuscin/ceroid granules are generated in the spiral ganglions under either endogenous (aging) or exogenous (vitamin E deficiency) conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175975
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    A hyaluronate secretor in the nasal mucosa: a cytochemical study using hyaluronidase-gold (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 237-239 
    Details
    ISSN: 1434-4726
    Keywords: Hyaluronate ; Hyaluronidase-gold ; Nasal mucosa ; Goblet cells ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural distribution of hyaluronate in the nasal mucosa of Wistar rats, especially in secretory cells, was examined by hyaluronidase-gold labeling using electron microscopy. The main secretor of hyaluronate in the nasal mucosa was found to be the goblet cells and not the nasal glands.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178993
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    Electron microscopic demonstration of sialic acid residues in the organ of Corti with lectin from Limax flavus (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 247 (1990), S. 240-243 
    Details
    ISSN: 1434-4726
    Keywords: Organ of Corti ; Limax flavus ; Feutin-gold ; Electron microscopy ; Sialic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The localization of sialic acid (N-acetyl- and N-glyconylneuraminic acid) in the organ of Corti of the mongolian gerbil was examined with electron microscopy by postembedding labeling using Limax flavus agglutinin and feutin-gold. Gold labeling was observed on the fibrous structure of the tectorial membrane, the basilar membrane and the spiral limbus. The labeling was also observed on the cuticular plate of the hair cells, the head and cone of the pillar cells and the head plate of Deiters' cells and other supporting cells. Collagen or cytoskeletal glycoproteins are suggested to be the source of the sialic acid in these structures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00178994
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    Mesothelium of Reissner's membrane in guinea pigs: an electron microscopic study (1990)
    Springer
    European archives of oto-rhino-laryngology and head & neck 248 (1990), S. 57-62 
    Details
    ISSN: 1434-4726
    Keywords: Vestibular membrane ; Reissner's membrane ; Mesothelium ; Fixation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The mesothelial cells of Reissner's membrane in guinea pigs were found to be connected by junctional complexes. No cell discontinuities or gaps were observed by scanning or transmission electron microscopy. These results are not in accordance with previous studies. They were achieved by in vivo vascular perfusion fixation, handling of cochleae in protective specimen carriers, thiocarbohydrazide treatment and continuous dehydration. Findings in the present study indicate that the interepithelial space between the epithelial and mesothelial cell layers constitutes a specific compartment which must be considered when examining solute transport over Reissner's membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00634783
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  • 65
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    Regiochemical Trends in Intramolecular [2 + 2] Photocycloadditions of 6-(prop-2-enyl)cyclohex-2-enones and 5-(prop-2-enyl)cyclopent-2-enonesDedicated to Prof. H. F. Mark, Brooklyn, in admiration and reverence on the occasion of his 95th birthday (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 288-297 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The effect of substituents (X = H, Me, or F at C(6), R = H or Me at C(2′) of the allyl side chain) on the photoisomerization (λ = 350 nm) of 6-allylcyclohex-2-enones 1 in MeCN is studied. Substituents X control the overall efficiency of intramolecular [2 + 2] photocycloadduct formation (Φ: Me 〉 F 〉 H) but do not exercise an influence on the orientation of addition of the exocyclic double bond to the enone C=C bond. In contrast, replacement of the prop-2-enyl (R = H) by a 2-methylprop-2-enyl (R = Me) side chain causes a change in the tricyclo[3.3.1.02,7]nonan-6-one 4 vs. tricyclo[4.2,1.03,8]nonan-7-one (5) product ratio from 100:0 (R = H) to roughly 2:1 (R = Me) but has almost no bearing on the relative rates of conversion of 1 to products. For C(6)-unsubstituted enones 1aa and 1ba (X = H), the efficiency of cyclization becomes low enough so that lumiketone rearrangement to bicyclohexanones 6 and 3-isopropylcyclopent-2-enones 9 becomes competitive. Enones 9 undergo consecutive intramolecular [2 + 2] photocycloaddition to tricyclo[3.2.1.03,6]octan-2-ones 7 and to tricyclo[3.2.1.03,6]octan-7-ones 8, compounds 8 only being formed when R = Me.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730208
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    Effets de substituant, d'hétéroatome et de solvant sur les cinétiques de décoloration thermique et les spectres d'absorption de photomérocyanines en série spiro[indoline-oxazine] (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 303-315 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Substituent, Heteroatom, and Solvent Effects on the Thermal-Bleaching Kinetics and Absorption Spectra of Photomerocyanines Issued from Spiro[indoline-oxazines]Quantitative information useful for the development of new photochromic systems is obtained from the study of heteroatom and substituent effects on the thermal-bleaching kinetics and the absorption spectra of the photomerocyanines issued from spiro[indoline-oxazines]. The effect on photochromic properties of the presence of N-atoms either in the dimethine bridge or in the aromatic rings has been investigated through the comparison of spiro[indoline-naphthopyrans] C with spiro[indoline-naphthoxazines] A and with spiro[indoline-quinolinoxazines] B. Besides the occurrence of biexponential thermal-bleaching kinetics in non-polar solvents is observed: a tentative explanation for this observation is given which involves the formation, in either sequential or parallel steps, of energetically distinct stereoisomers of the opened form.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730210
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    Stereoselectivity and Chiral Recognition in the Electron-Transfer Reaction between Spinach Ferredoxin and Optically Active Cobalt(III) ComplexesPart XIII of the series ‘Stereoselectivity in Reactions of Metal Complexes’. For Part XII, see [1]. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 346-352 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The kinetics of the electron transfer between reduced spinach [2Fe-2S]-ferredoxin and the optically active complexes [Co((R,R)- or (S,S)-alamp)py]+ (I), [Co((R,R)- or (S,S)-promp)H2O]+ (IIa), and [Co((R,R)- or (S,S)-promp)py]+ (IIb) have been investigated. The reactions are stereoselective, and for I and IIa, the Stereoselectivity strongly depends on temperature due to large differences in the activation enthalpy between enantiomeric reagents. Isokinetic behaviour is observed between enantiomers, the ΔΔHΔ-Λ# values being largely compensated by the ΔΔSΔ-Λ# values. The compensation behaviour is explained by the combination of stereochemical interactions and desolvation processes on formation of the precursor complex or the transition state.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730214
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    A Facile Synthesis of Optically Pure (-)-(S)-Ipsenol Using a Chiral Titanium ComplexPart 6 of ‘Enantioselective Syntheses with Titanium-Carbohydrate Complexes’; part 5, see [1]. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 353-358 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A stereocontrolled synthetic route to optically pure (-)-(S)-ipsenol (1), the pheromone of Pityokteines curvidens and various other bark-beetle species is described. Key step of the synthesis is an enantioselective aldol reaction using a chiral titanium-carbohydrate complex (Scheme 1). The carboxylate function of the optically pure β-hydroxy acid 5 thus obtained in mol quantities is then elaborated to the diene moiety by standard methodology (Scheme 2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730215
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    Synthese von 2-Oxo-2H-pyran-5-Carboxylat-Derivaten (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 411-416 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis of 2-Oxo-2H-pyran-5-carboxylate Derivatives3-Substituted diethyl pent-2-enedioates are easily formylated by means of ethyl formate/TiCl4/4-methylmorpholine to produce the ethoxymethylene derivatives, which are smoothly cyclized either with HCOOH or PPA to corresponding 2-oxo-2H-pyran-5-carboxylate derivatives.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730220
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    Potential antipsychotic agents. Part 8Part 7: [1].. Antidopaminergic properties of a potent series of 5-substituted (-)-(S)-N-[(1-ethylpyrrolidin-2-yl)methyl]-2,3-dimethoxybcnzaimides. Synthesis via common lithio intermediates (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 417-425 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of 5-substituted (-)-(S)-N-[(1-ethylpyrrolidin-2-yl)methyl]-2,3-diniethoxybenzanndes were made by reaction of the corresponding benzoyl chlorides with (S)-1-ethylpyrrolidine-2-methylaruine (→ 14-16, 18-21). The acids required were prepared in a regiospecific manner from 5-bromo-2,3-dimethoxybenzoic acid which was protected as dihydrooxazole (→ 4-8), metalated, reacted with various electrophiles (MeI, EtI, BuBr, CC13CCl3 or MeSSMe), and hydrolyzed (→9-13). Alternatively, (-)-(S)-5-bromo-N-[(1-ethylpyrrolidin-2-yl)methyl]-2,3-di-methoxybenzamide was treated with KH followed by BuLi and an electrophile (I2 or Me3SiCl) to give the 5-iodo and 5-(trimethylsilyl) derivatives 17 and 22, respectively. All 5-substituted amides were highly potent inhibitors of [3H]spiperone binding in rat striatal membranes with IC50 values of 0.5 to 5 nM (Table 3). Thus, a relatively large steric bulk can be accomodated in the position para to the 2-MeO group. This work also supports the notion that a positive as well as negative electrostatic potential can be located in this position. A selected number of derivatives were also investigated in vivo and found to inhibit apomorphine-induced behavioural responses in the same dose range as haloperidol and raclopride (Table 4). This new group of benzamides is suitable for investigations of dopamine D-2 receptors in labelled or unlabelled form.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730221
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    Stereoselective Coordination to Chiral Matrices. Cobalt(III). Chemistry of Simple Facially Coordinating Chiral Triamines (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 874-882 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Chiral ligands coordinated to metal ions exert a selectivity towards the additional coordination of racemic substrates. Experimentally determined equilibria distributions of [Co(L3)2]3+ and [Co(L3)(L2)(X)]n+ are compared with calculated data based on strain-energy minimization (L3: trap = propane-1,2,3-triamine; 1,2,4-trab = butane-1,2,4-triamine; 1,2,3-trab = butane-1,2,3-triamine; 1,3,4-trpe = pentane-1,3,4-triamine; 1,3,4-tmeb = 2-methylbutane-1,3,4-triamine; 1,2,4-trpe = pentane-1,2,4-triamine; L2: en = ethane-1,2-diamine; pn = propane-1,2-diamine; X: NH3, OH2, OH-). Equilibration of Co(III) complexes was achieved by oxygenation of aqueous solutions of Co(II) salts in presence of the ligands. Quantitative isomer distribution was investigated with HPLC, and quantitative analysis of the enantiomeric excess (ee) of the racemic substrate (present in a two-fold excess) was studied, after chromatographical recovery, by 1H-NMR analysis of its Mosher-acid derivative. There is good agreement between calculated and experimental data. Systems with L = 1,2,4-trab are, as expected, relatively poorly discriminating (ee([Co(1,2,4-trab)2]3+) ∼ 5%; ee([Co(1,2,4-trab)(pn)(X)]n+) ∼ 10%). Calculations indicate that Me substitution of the ligand backbone of 1,2,4-trab (and trap) leads to an increased enantioselectivity (with practically constant isomer selectivity), and at the optimum site for substitution ∼ 90% ee is predicted.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730413
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    Reaction of 3-Amino-2H-azirines with 2-Amino-4,6-dinitrophenol (Picramic Acid): Synthesis of Quinazoline- and 1,3-Benzoxazole DerivativesPresented (H. H.) at the ‘International Symposium über Stickstoff-Ringe und -Ketten’, Heidelberg, March 19-21, 1990. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 959-974 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The reaction of 3-(dimethylamino)-2H-azirines 1a-c and 2-amino-4,6-dinitrophenol (picramic acid, 2) in MeCN at 0° to room temperature leads to a mixture of the corresponding 1,2,3,4-tetrahydroquinazoline-2-one 5, 3-(dimethylamino)-1,2-dihydroquinazoline 6, 2-(1-aminoalkyl)-1,3-benzoxazole 7, and N-[2-(dimethylamino)phenyl]-α-aminocarboxamide 8 (Scheme 3). Under the same conditions, 3-(N-methyl-N-phenyl-amino)-2H-azirines 1d and 1e react with 2 to give exclusively the 1,3-benzoxazole derivative 7. The structure of the products has been established by X-ray crystallography. Two different reaction mechanisms for the formation of 7 are discussed in Scheme 6. Treatment of 7 with phenyl isocyanate, 4-nitrobenzoyl chloride, tosyl chloride, and HCl leads to a derivatization of the NH2-group of 7 (Scheme 4). With NaOH or NaOMe as well as with morpholine, 7 is transformed into quinazoline derivatives 5, 14, and 15, respectively, via ring expansion (Scheme 5). In case of the reaction with morpholine, a second product 16, corresponding to structure 8, is isolated. With these results, the reaction of 1 and 2 is interpreted as the primary formation of 7, which, under the reaction conditions, reacts with Me2NH to yield the secondary products 5, 6, and 8 (Scheme 7).
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730423
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    Analogues of Sialic Acids as Potential Sialidase Inhibitors Synthesis of 2-C-Hydroxymethyl Derivatives of N-Acetyl-6-amino-2,6-dideoxy-neuraminic Acid (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 940-958 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The intramolecular cycloaddition of the previously described azidoalkene 16, the related diacetates 7 and 13, and the monoacetate 8 led diastereoselectivity to the (2R)- and (2S)-configurated hydropyridotriazoles 17, 9 and 11, 14 and 15, and 10 and 12, respectively (Scheme 1). Thermolysis of 16 gave also the aziridine 18, its proportion increasing with reaction time. The diastereoselectivity of the cycloaddition- is rationalized on the basis of steric interactions and of H—bonds in the transition state. Photolysis in benzene partially transformed 9 into the aziridine 19. Treatment of 9 with aqueous AcOH gave 19 and the tetrahydrofuran 20, with AcOH in benzene 20 and the triacetate 23, and with aqueous H2SO4 in THF, the primary alcohol 22 (room temperature) or 19 and 22 (0°). Deacetylation of 9 followed by reaction with pyridinium hydrochloride led to the tetrahydrofuran 21 and the chloride 24 (Scheme 2). The diacetate 22 and the triacetate 23 gave the tripl 25 which was deprotected to 26. Reduction of the keto-aziridine 18 (NaBH4) gave the alcohols 27 and 29 which were acetylated to give 28 and 19, respectively (Scheme 3). Treatment of the aziridine 28 with AcOH in benzene followed by deacetylation gave 30 and hence 31. AcOH in benzene transformed the triazoline 15 first into the aziridine 32 and hence into 33, which was deprotected to give the triol 34 and hence 35. The 2-(hydroxymethyl)piperidines 26, 31, and 35 inhibited Vibrio cholerae sialidase with K1 = 3.8 · 10-2 M, 3.4 · 10-3 M, and 1.5 · 10-4 M, respectively. The conformation of the glycerol side chain of these compounds and of the unbranched piperidines 2-4 deviates from the one of Neu5Ac (and Neu2en5Ac). This finding is rationalized by an H-bond between OH—C(8) and NH—C(6). The conformations and the K1 values of 26, 31, and 35 correlate with each other.
    Additional Material: 3 Tab.
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  • 74
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    Synthesis of IH-Cyclopropal[g]quinoline via Trapping of an ortho-Quinodimethane (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1228-1232 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1H-Cyclopropa[g]quinoline (3-aza-lH-cyclopropa[b]naphthalene; 17) was synthesized via interception of the heterocyclic ortho -quinodimethane 15 with l-bromo-2-chlorocyclopropene, followed by aromatization of the adduct 16 with t-BuOK.
    Additional Material: 1 Ill.
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  • 75
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    Isolation and Characterization of s̰-Adducts upon Attempted Vicarious Nucleophilic Substitution with Cationic Arene-Iron Complexes (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1242-1249 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of the carbanions derived from chloromethyl phenyl sulfone or 1 -chloroethyl phenyl sulfone with the cationic [Fe(arene)Cp] complexes 8 or 9 produced isolable c-adducts 10-12. Attempted base induced elimination of the s̰-adducts, which would have led to products of vicarious nucleophilic substitution (VNS reaction), failed. Similarly, no VNS products were obtained, when the (arene)tricarbonylchromium complexes 4 were reacted with the anion of chloromethyl phenyl sulfone.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19900730514
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  • 76
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    A New Convergent Synthesis of Thiamine HydrochlorideDedicated to Dr. Otto Isler on the occasion of his 80th birthday (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1300-1305 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Thiamine hydrochloride (1a; 3-[(4-amino-2-methylpyrimidin-5-yl)methyl]-5-(2-hydroxyethyl)-4-methylthia-zolium chloride hydrochloride; vitamin B1) has been synthesized in excellent yield by condensation of 3-mercapto-4-oxopentyl acetate (5a) with 3, 4-dihydro-7-methylpyrimido[4, 5-d]pyrimidine (4) in formic acid. The two intermediates 5a and 4 are prepared from 3-chloro-4-oxopentyl acetate (3) and 4-amino-2-methyl-5-(aminomethyl)-pyrimidine (Grewe diamine; 2a), respectively.
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    URL: http://dx.doi.org/10.1002/hlca.19900730518
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  • 77
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    Ringerweiterungen und Ringverengungen bei der Umsetzung von 1, 3-Oxazolidin-2, 4-dionen und 1, 3-Thiazoiidin-2, 4-dion mit 3-Amino-2H-azirinen (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1314-1328 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring Enlargements and Ring Contractions in the Reaction of 1, 3-Oxazolidine-2, 4-diones and l, 3-Thiazolidine-2, 4-dione with 3-Amino-2H-azirinesThe reaction of 3-amino-2H-azirines 1 and 1, 3-oxazolidine-2, 4-diones 2 in MeCN at room temperature leads to 3, 4-dihydro-3-(2-hydroxyacetyl)-2H-imidazol-2-ones 3 in good yield (Scheme 2, Table 1). A reaction mechanism proceeding via ring enlargement of the bicyclic zwitterion A to give B, followed by transannular ring contraction to C, is proposed for the formation of 3. This mechanism is in accordance with the result of the reaction of 2a and the 15N-labelled 1a*: in the isolated product 3a*, only N(3) is labelled (Scheme 1). The analogous reaction of 1 and 1, 3-thiazolidine-2, 4-dione (5) is more complex (Schemes 4 and 5, Table 2). Besides the expected 3, 4-dihydro-3-(2-mercaptoacetyl)-2H-imidazol-2-ones 7, 5-amino-3, 4-dihydro-2H-imidazol-2-ones of type 8 and/or N-(1, 4-thiazin-2-ylidene)ureas 9 are formed. In the case of 2-(dimethylamino)-1-azaspiro[2. 3]hex-1-ene (1d), the postulated eight-membered intermediate 6d could be isolated. Its structure as well as that of 9f has been determined by X-ray structure analysis. A reaction mechanism for the formation of the 1, 4-thiazine derivatives of type 9 is proposed in Scheme 6.
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  • 78
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    Synthesis of Potential Glucosidase-Inhibitors: D-Xylopyranoside-5-spiro-l′-cyclopropanesTaken in part from the thesis of L.P.M. [1] (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1329-1337 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of the D-xylopyranose-5-spiro-1′-cyclopropane 5, its methyl α-D-glycoside 7 and its benzyl β-D-glycoside 13 from D-glucose is described, and their conformation in solution is discussed. A Königs-Knorr glycosidation of 10 reveals the ionic intermediate of a 1, 1-(dibromocyclopropyl)carboxonium ion type to be stable against opening of the cyclopropane ring. Very weak inhibition of saccharase was observed for the α-D-configurated methyl glycoside 7, whereas the β-D-configurated benzyl glycoside 13 did not inhibit emulsin.
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  • 79
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    Chemie von α-Aminonitrilen.2. Mitteilung über die Chemie von α-Aminonitrilen. 1. Mitteilung:[1]. Aziridin-2-carbonitril photochemische Bildung aus 2-AminopropennitrilOtto Isler gewidmet (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1373-1390 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: 2-Aminopropenenitrile in solvents such as MeCN, MeOH, or H2O is photoisomerized by UV light to racemic aziridine-2-carbonitrile (rac-2); the larger part of the starting material, however, fragments to HCN and MeCN. The observed photocyclization constitutes a structural connection within an ensemble of C3H4N2 compounds considered to be potentially relevant to prebiotic chemistry.
    Notes: No Abstract.The English Footnotes (*) referring to Schemes 1-6 are intended to provide an extension of this summary. In the Footnote (*) to Scheme 5, a definition of the term ‘chirogenic reaction step’ is given.
    Additional Material: 1 Ill.
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  • 80
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    Elektrophile Substitutionsreaktionen des 1,1-Difluoro-1H-cyclopropabenzolsHerrn Prof. Dr. Dr. h. c. mult. Rolf Huisgen zum 70. Geburtstag gewidmet (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1497-1503 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electrophilic Substitution Reactions of 1,1-;Difluoro-1H-cyclopropabenzene1,1-Difluoro-1H-cyclopropabenzene (1) can be deprotonated with strong bases at C(2). The resulting 1,1-di-fluoro-2-lithio-1H-cyclopropabenzene (2) reacts with electrophiles to form C(2)-substituted derivatives of 1. The Diels-Alder reactions with electron-poor dienes, characteristic for 1H-cyclopropabenzene, do not occur with the 1,1-difluoro analogue 1.
    Additional Material: 1 Tab.
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    URL: http://dx.doi.org/10.1002/hlca.19900730529
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  • 81
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    Eine Synthese methylierter Epoxyhydroazulenone durch intramolekulare [4 + 3]-Cycloaddition einer aus 1,1-Dichloro-6-(3-methylfur-2-yl)hexan-2-on erzeugten Oxyallyl-ZwischenstufeAus der Dissertation von R. K[1].Diese Arbeit Wurde erstmals auf dem ‘6th European Symposium on Organic Chemistry, ESOC 6’, vom 10-15.9.1989 in Belgrad, Jugoslawien, vorgestellt; Book of Abstracts A-O 022, S,40. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1504-1514 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A synthesis of Methylated Epoxyhydroazulenones by Intramolecular [4 + 3] Cycloaddition of an Oxyallyl Intermediate, Generated from 1,1-Dichloro-6-(3-methyl-2-furyl)hexan-2-one(Z)-3-Methylpent-2-en-4-yn-1-ol (7) was transformed to 2-(4-chlorobutyl)-3-methylfuran (4b) and 2-(but-3-enyl)-3-methylfuran (10a) by C-alkylation and 5-exo-dig cyclization. The Grignard derivative formed from 4b gave 1,1-dichloro-6-(3-methylfur-2-yl)hexan-2-onc (1b) on reaction with dichloroacetyl chloride. This dichloromethyl ketone undergoes a base-induced cyclization to form diastereoisomeric 7-chloro-1,2,3,6,7,8a-hexahydro-4-methyl-8H-3a,6-epoxyazulen-8-ones (3bα and 3bβ) by way of an intramolecular [4+3] cycloaddition of an oxyallyl intermediate 2b. By dechlorination and hydrogenation of 3bβ, the tricyclic hydroepoxyazulenones 18 and 19 have been synthesized.
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  • 82
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    Rogiolol Acetate: A Novel β-Chamigrene-Type Sesquiterpene Isolated from a Marine SpongeWe use the chamigrene numbering for the structural formulae and spectroscopic data; IUPAC nomenclature and numbering are used for retrieval purposes (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1612-1620 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The marine sponge Spongia zimocca SCHMIDT, 1862, collected in front of the torrent II Rogiolo, south of Livorno, contains the sesquiterpene rogiolol acetate (= (+)-(2R,3S,6R,8R,9R)-2,8-dibromo-9-chloro-1,1,9-trimethyl-5-methylidenespiro[5.5]undec-3-yl acetate; (+)-3a), which represents the first chamigrane isolated from a sponge. Although compounds of this class are common in red seaweeds of the genus Laurencia, and our sponge actually contains 9-bromochamigrene and a variety of other metabolites of nearby growing Laurencia sp., (+)-3a is unique to our sponge.
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/hlca.19900730606
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  • 83
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    Stereochemistry of the Robinson Anellation: Studies on the Mode of Formation of the Intermediate Hydroxy Ketones (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1621-1636 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The stereochemical outcome of the base-catalyzed cyclization of diketones 5-8 has been investigated under protic conditions (Scheme 3). The more stable trans-fused ketols are preferentially formed in kinetically controlled aldol reactions, when the incipient angular substituent R = H (6 → 10a) or CN (7 → 11a, 8a → 12a). For R = Me (as in 5), axial attack of the side-chain enolate double bond on the ring C≡O group results in the rather selective formation of cis-9b. It is assumed that these cyclizations are controlled by relative product stabilities (product-like transition state) and steric effects. The competition between fused (e.g. 9) and bridged ketol (e.g. 13) formation in these cyclizations is discussed. The cis-fused (‘steroid’) ketols were readily equilibrated with their trans-counterparts (9b ⇄ 9a, 10b ⇄ 10a, 11b ⇄ 11a) under aprotic conditions (5 mol-% of LDA, THF, 0°), thus, allowing assessments of relative stabilities.
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  • 84
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    The Reaction of Singlet Oxygen with Adamantylideneadamantane Mediated by Rose Bengal (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1653-1658 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The photo-oxygenation of adamantylideneadamantane (1) on siliceous supports using admixed granules of ion-exchange resin fixed to methylene blue (MB) and rose bengal (RB) gave exclusively the corresponding dioxetane derivative 2 for the former sensitizer, while the latter gave 2 and traces of the epoxide 3. RB and the charge-transfer complex produced from N-ethylcarbazole and 2,4,5,6-tetranitrofluoren-9-one both reacted with chemically generated singlet oxygen to give superoxide radical anion. Trapping of the latter with 5,5-dimethyl-1-pyrroline 1-oxide gave an adduct exhibiting a characteristic ESR spectrum. The treatment of 1 in MeOH with 30% aqueous H2O2 for 22 h at 60° gave 3 in 100% yield. Repetition of this experiment in the presence of 2,6-di(tert-butyl)-p-cresol caused no significant change. These results indicate that singlet oxygen reacts with 1, in the presence of RB, by two different processes. The first leads to dioxetane formation. The second process involves conversion of singlet oxygen by RB to superoxide radical anion which subsequently gives H2O2 so producing epoxide 3 from 1.
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    Synthesis and Properties of a New Dihydroflavin: Reduction of a Flavinium Salt by BorocyanohydridePreliminary results were reported at the ‘Fifth International Symposium on Flavins and Flavoproteins’; San Francisco, March 31-April 3 1975. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1669-1678 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reduction of 6 by borocyanohydride yielded the new dihydroflavin 7. The intermediate product 8 could only be observed in solution by 1H-NMR. The chemical and physical properties of 7 are reported. UV/VIS, 1H- and 13C-NMR, and luminescence techniques were used.
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  • 86
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    The Photoreversible Addition of Sulfur Dioxide to Benzobenzvalene: A new Approach to the Benzoprefulvene Biradical (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1724-1729 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Benzobenzvalene (naphthvalene; 1) is shown to add SO2 to a lateral bicyclobutane bond with formation of a sulfone 2 and a ‘γ-sultine’ 3. The structure of the latter is unambiguously established by X-ray diffraction. Both adducts extrude SO2 upon direct photolysis at 254 nm and regenerate 1 accompanied by naphthalene in a 1:3 ratio. This result is interpreted in terms of a reversible homolytic cleavage leading, for both, 2 and 3, to the same sulfinyloxy biradical 5, which by loss of SO2 gives the benzoprefulvene biradical 6. The latter in its singlet state undergoes ring closure to 1, or it opens to give naphthalene.
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  • 87
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    Glycosylidene Carbenes. Part 2. Synthesis of O-Aryl Glycosides (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1764-1778 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Phenol, 4-methoxyphenol, 4-nitrophenol, methyl orsellinate (1), and 2,6-di(tert-butyl)-4-methylphenol (BHT; 2) have been glycosylated by thermal reaction (20-60°) with various glycosylidene-derived diazirines.4-Methoxyphenol reacted with the D-glucosylidene-derived diazirine 3 to give O-glucosides (4 and 5, 69%, 3:1) and C-glucosides (6 and 7, 16%, 1:1). Similarly, phenol yielded O-glucosides (10 and 11, 70%, 4:1) and C-glucosides (12 and 13, 13%, 1:1). 4-Nitrophenol gave only O-glycosides, 3 leading to 14 and 15 (75%, 3:2; Scheme 1), and the D-galactosylidene-derived diazirine 17 to 22 and 23 (52% (from 16), 65:35; Scheme 2). The reaction of phenol with 17 yielded 58% (from 16) of the O-galactosides 18 and 19 (4:1) and 14% of the C-galactosides 20 and 21 (1:1). From the D-mannosylidene-derived diazirine 25, we predominantly obtained the α-D-configurated 26 (38 % from 24). These results are interpreted by assuming that an intermediate (presumably a glycosylidene carbene) first deprotonates the phenol to generate an ion pair which combines to give O- and - with electron-rich phenolates - also C-glycosides. A competition experiment of 3 with 4-nitro- and 4-methoxyphenol gave the products from the former (14 and 15) and the latter phenol (4-7) in almost equal amounts. Differences in the kinetic acidity of OH groups, however, may form the basis of a regioselective glycosidation, as evidenced by the reaction of 3 with methyl orsellinate (1) yielding exclusively the 4-O-monoglycosylated products 27 and 28 (78%, 85:15), although diglycosidation is possible (27→ 31 and 32; 67%, 4:3; Scheme 3). Steric hindrance does not affect this type of glycosidation; 3 reacted with the hindered BHT (2) to afford 33 and 34 (81 %, 4:1). The predominant formation of 1,2-trans -configurated O-aryl glycosides is rationalized by a neighbouring-group participation of the 2-benzyloxy group.
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    Anion Selectivity of Tetravalent Tin Compounds in Membranes Studied by 119Sn-, 13C- and 1H-NMR (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1894-1904 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The fundamental molecular aspects of trialkyltin compounds of the type R3SnY have been investigated in view of their applicability as ion-selective components in solvent polymeric membranes. The interaction between these compounds and anions has been studied using 119Sn- and 13C-NMR. Neutral tetracoordinated trialkyltin compounds form a negatively charged pentacoordinated complex upon interaction with Cl-ions in homogeneous organic phases as well as in membranes in contact with aqueous solutions. Although in a homogeneous phase, the electronegative substituent Y determines the complex-formation constant, it has no influence on the potentiometric anion selectivity in liquid membranes containing trialkyltin carriers R3SnY with different Y. The observed selectivity pattern is not given by the magnitude of the stability constants in a homogeneous phase but is dictated by the prevailing association-dissociation process leading to tetracoordinated compounds which change in constitution due to varying sample composition, The results obtained from equilibrium studies of tetravalent mono tin compounds with anions in both homogeneous phase and in two-phase systems confirm the earlier hypothesis that trialkyltin compounds incorporated in solvent polymeric membranes act as electrically neutral carriers for anions.
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  • 89
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    Stereoelectronic Aspects of the Anomeric Effect in Fluoromethylamine (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1805-1817 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High-level ab initio calculations have been made for fluoromethylamine to study structural and energetic effects of the relative orientation of the N lone pair to the C—F bond. The anti-conformer (N lone pair anti-planar to the C—F bond) corresponds to the global energy minimum. It has the longest C—F distance, the shortest C—N distance, and is 7.5 kcal·mol-1 more stable than the related perpendicular conformation (lone pair perpendicular to the C—F bond). The syn-conformation also shows hallmarks of the anomeric effect: long C—F bond, short C—N bond, and energetic stability when allowance is made for the two pairs of eclipsed hydrogens. The transition state for N inversion is close to the syn-structure; rotation about the C—N bond is strongly coupled with this inversion process. Small bond distance changes of ca. 0.02 Å between parallel and perpendicular conformations are associated with dissociation energy differences of ca. 30 kcal·mol-1. Various criteria for assessing the strength of the anomeric effect are discussed.
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    URL: http://dx.doi.org/10.1002/hlca.19900730702
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  • 90
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    Enzyme-Mediated Regioselective Acylations of Flavonoid Disaccharide Monoglycosides (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1837-1844 
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    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Flavonoid disaccharide monoglycosides have been acylated by the catalytic action of the protease subtilisin in anhydrous pyridine. The effects of the nature of the sugars and of the interglycosidic bonds on the regioselectivity of the reactions have been analyzed. The selectivity was excellent with rutin (1), hesperidin (2), naringin (6), and quercetin 3-O-[O-(β-D-glucopyranosyl)-(1→4)-α-L-rhamnoside] (9), giving single monoesters on their glucose moieties (see la, 2a, 6a, and 9b, resp.); quite interestingly, in the last compound, acylation did not occur at the free primary OH group but at the secondary OH—C(3‴). On the other hand, a mixture of mono- and diesters was obtained with the flavonoid peltatoside (7).
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730705
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  • 91
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    The chemistry of coumarin derivatives, part 2.Part 1, see [1a] Reaction of 4-hydroxycoumarin with α,β-unsaturated aldehydes (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1865-1878 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 4-Hydroxycoumarin (= 4-hydroxy-2H-1-benzopyran-2-one) reacts with enals to give 1,2- or 1,4-addition products, depending on the nature and relative location of the substituents on the olefinic double bond (Scheme 2). The resulting adducts further react intra- or intermolecularly, affording dimeric coumarins or pyranocoumarins in the case of 1,2-addition and acetalic pyranocoumarins in the case of 1,4-addition. With enals bearing alkyl groups at C(β), 2H-pyrano[3,2-c]coumarins are the only products formed, and the reaction represents an easy and straightforward entry into this class of recently described biologically active natural products.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730709
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  • 92
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    Synthesis and Configuration of Some Hydroxymilbemycin Derivatives Including 22,23-Dihydroavermectin B1b AglyconeDedicated to Prof. Oskar Jeger (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1905-1917 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of several configurationally defined hydroxymilbemycin derivatives is described. One of these allylic alcohols is the known 5-O-[(tert-butyl)dimethylsilyl]-13α-hydroxymilbemycin D (= 5-O-[(tert-butyl)-dimethylsilyl]-22,23-dihydroavermectin B1b, aglycone; 15D), the synthesis of which represents LI conversion of the milbemycin to the avermectin series of natural products. The configurations at C(13), C(14), and C(15) of the new milbemycin derivatives were determined by NMR experiments and force-field calculations.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730713
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  • 93
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    Configuration-Odor Relationships in 5β-Ambrox (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 1935-1947 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The four possible A/B cis-fused diastereoisomers of Ambrox® have been synthesized and their configurations and conformations established by X-ray and NMR analysis. Only 5β-ambrox (= 1,2,3a,4,5,5β,6,7,8,9,9a,9bα-dodecahydro-3aβ,6,6,9aβ-tetramethylnaphtho[2,1-b]furan; 5) has an odor quality comparable to Ambrox®. The 1,3-synperiplanar/diaxial conformation of the substituents at C(8) ( = C(3a)) and C(10) (= C(9a)) has thus been confirmed to be a compulsory structure element for the particular odor.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730717
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  • 94
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    Mitteilungen (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 2070-2070 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730727
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  • 95
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    Metal Complexes with Macrocyclic Ligands. Part XXXIPart XXX: see [1].. Protonation studies and complexation properties of tetraazamacrocyclic methylenephosphonates with earth-alkali ions (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 140-148 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The three ligands 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylenephosphonic acid) (1), 1,4,7,11-tetraazacyclotridecane-1,4,7,11-tetrakis(methylenephosphonic acid) (2), and 1,4,8,11-tetraazacyclotetradecane-1,4,8,1 1-tetrakis(methylenephosphonic acid) (3) have been synthesized by condensation of the corresponding macrocycles with formaldehyde and phosphorous acid. The protonation and stability constants with the earth-alkali ions have been determined at 25° and I = 0.1 M (Me4)N(NO3) by potentiometric titrations. Because of the high values of the first two protonation constants, 1H-NMR measurements were necessary to determine them. Titrations in different supporting electrolytes (NaNO3, KNO3, RbNO3, CsNO3, and Me4N(NO3)) show that their choice is of paramount importance, as the above ligands can form complexes with alkali-metal ions. The potentiometric results for the earth-alkali ions show that beside mononuclear complexes of different degrees of protonation ([MLHn], n = 0-4), also binuclear species are formed ([M2LHm], m = 0-2). It is interesting that 1 with the smallest macrocyclic ring has the greatest tendency to form binuclear complexes, which are so stable that they partially prevent the formation of the corresponding mononuclear species. For [ML], [MLH], [M2L], and [M2LH], the stability sequence is Mg2+ 〈 Ca2+ 〉 Sr2+ 〉 Ba2+, whereas for [MLH2], [MLH3], and [MLH4], the stability steadily decreases from Mg2+ to Ba2+.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730115
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  • 96
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    Intramolecular Dynamics of Tetranuclear Iridium Carbonyl Cluster Compounds. Part IIIPart I and II: see[8]. Crystallographic and dynamic evidence for the intermediate of the ‘merry-go-round’ process in nonacarbonyl-μ3-(1,3,5-trithiane)-tetrairidium (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 154-160 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The title complex crystallises in two C3v, isomeric forms differing in carbonyl-ligand arrangement. In solution, the isomer 1b with three edge-bridging carbonyls on a common face of the metal tetrahedron converts via an endothermic equilibrium into the isomer 1u with no bridging carbonyls. The latter was shown by 13C-NMR to be the intermediate of the ‘merry-go-round’ process which exchanges the sites of the basal CO's.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730117
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  • 97
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    Total Syntheses of (-)-Conduritol B ((-)-1L-Cyclohex-5-ene-1,3/2,4-tetrol) and of (+)-Conduritol F((+)-1D-Cyclohex-5-ene-1,2,4/3-tetrol). Determination of the Absolute Configuration of (+)-LeucanthemitoEnantiomerically pure 7-oxabicyclo [2.2.1]hept-5-en-2-yl derivatives (‘naked sugars’[1]) as synthetic intermediates, Part XI. Part X, see[2];Part IX, see[3]. (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 161-168 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ‘naked sugar’ (+)-(1R,2R4R)-2-endo-cyano-7-oxabicyclo[2.2.1]hept-5-sn-2-exo-yl acetate ((+)-4) was converted (7 steps, 45% overall) with high stereoselectivity into (-)-(4R,5S,6R)-4,5,6-tris{[(tert-butyl)dimethylsilyl]oxy}cyclohex-2-en-1-one ((-)-11). Reduction of (-)-1 with NaBH4- CeCl3 · 7 H2O, followed by deprotection of the silyl ether moieties gave (+)-conduritol F ((+)-1; 47%) whose characteristics were identical to those of natural (+)-leucanthemitol. Reduction of (-)-11 with DIBAH, followed by deprotection of the silyl ether moiety led to (-)-conduritol B ((-)-3; 51 %).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730118
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  • 98
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    A Novel Nitrone Cycloaddition/Rearrangement (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 169-173 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Adamantanone-derived nitrone 4 and some other keto-nitrones, when reacted with aromatic and aliphatic aldehydes in refluxing toluene or tetrahydrofuran, formed the corresponding aldonitrones (Z)-10, the latter arising from the fragmentation of an initially formed 1,4,2-dioxazolidine 6 to adamantan-2-one and an oxaziridine intermediate 11, which then rearranges to (Z)-10.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730119
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  • 99
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    Synthesis of Derivatives of (1R*,10aR*)-1-Azido-10-benzylidene-4-(diethylphosphono)-1,2,10,10a-tetrahydro-2-oxo-4H-azeto[1,2-a]pyrido[1,2-d]pyrazin-9-ylium Bromide (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 180-184 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The synthesis of some derivatives of the title compound VI is described. Bromination of diethyl (cis-3-azido-2-oxo-4-styrylazetidin-1-yl)(pyridin-2-yl)methylphosphonate (6) in MeOH gave tricyclic β-lactam 7, while similar bromination of diethyl (cis-3-azido-2-oxo-4-vinylazetidin-1-yl)(pyridin-2-yl)methylphosphonate (9) afforded tri-cyclic β-lactam 10. Mechanisms for these transformations are proposed (Schemes 1 and 2).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730121
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  • 100
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    Synthesis and Complexation of 1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoxime. Crystal Structure of (1,2-Bis[(monoaza[15]crown-5)-N-yl]glyoximato)palladium(II) (1990)
    New York, NY : Wiley-Blackwell
    Helvetica Chimica Acta 73 (1990), S. 174-179 
    Details
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A new vicinal dioxime ligand with two crown-ether groups, 1,2-bis[(monoaza[15]crown-5)-N-Yl]-glyoxime(LH2), has been prepared from cyanogen di-N-oxide and monoaza[15]crown-5. Ni(II), Pd(II), and Pt(IV) complexes of LH2 with or without alkali-metal ions bound to macrocyclic groups have been isolated. The high affinity of [Pd(LH)2] and [Ni(LH)2] for the K+ ion is observed in solvent extraction experiments. A single-crystal X-ray structure confirms the postulated geometry of [Pd(LH)2]- The Pd-atom of the centro-symmetric molecule has square-planar PdN4 coordination where Pd-N distances range from 1.978(3) to 1.970(3) Å. The N-Pd-N intraligand angle is 79.9(1)°.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/hlca.19900730120
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