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C Sommer

Publications and source records attributed to C Sommer.

141 records · Page 8Linked to original sources
PubMed1990

Pancreatic enzyme synthesis and secretion are independently regulated by insulin and glucocorticosteroids.

Both insulin and glucocorticosteroid (GS) deficiency causes a reduction of amylase synthesis and changes in the dose-response curve of cholecystokinin (CCK) stimulated enzyme secretion in rats. Since we found a reduction of plasma insulin in adrenalectomized rats, we now tested the hypothesis that the regulation of amylase synthesis by insulin may be mediated by GS. Three groups of male rats were investigated: controls, streptozotocin induced diabetics, and diabetics treated with GS. Animals were sacrificed 10-14 days after injection of streptozotocin and isolated pancreatic acini prepared by collagenase digestion. Protein synthesis was measured on the translational level by incubation of acini with 35S-methionine followed by lysis of cells and separation of proteins by SDS-PAGE. In addition, protein synthesis was measured on the transcriptional level by isolation of mRNA from pancreatic acini and translation of proteins using the rabbit reticulocyte lysate system. The loss of insulin in diabetic rats was associated with a 70-90% decrease in amylase synthesis and increases of synthesis of various proteases. This was due to a specific decrease in mRNA coding for amylase and increase in mRNA coding for proteases. Furthermore, the known rightward shift of the dose response curves of CCK stimulated amylase secretion was seen in diabetic animals. Treatment of diabetic rats with GS did deteriorate the catabolic status seen in diabetes with increases in mortality as compared to diabetes alone. However, neither the overall pattern of enzyme synthesis seen in diabetic rats nor the alterations in CCK stimulated enzyme secretion were changed by treatment with GS. We conclude that the regulation of amylase synthesis and enzyme secretion by insulin is not mediated via GS.

Amylases↗
PubMed1989

Hereditary motor and sensory neuropathy with optic atrophy. Ultrastructural and morphometric observations on nerve fibers, mitochondria, and dense-cored vesicles.

Nerve biopsy specimens from three cases of hereditary motor and sensory neuropathy with optic atrophy were studied by light and electron microscopy and by morphometry. All cases had a chronic neuropathy of the neuronal/axonal type with little, presumably secondary, demyelination. There was predominant reduction of the large-caliber population of myelinated and unmyelinated nerve fibers. The number of dense-cored vesicles in unmyelinated and small myelinated fibers was increased. Abnormal mitochondria in Schwann cells with paracrystalline inclusions, prominent cristae including paracrystalline material (cases 1 and 2), and axonal mitochondria with presumable hydroxyapatite crystals (case 3) were found. The morphologic results suggest that hereditary motor and sensory neuropathy with optic atrophy should be regarded as a separate entity within the hereditary motor and sensory neuropathy group.

Adolescent↗
PubMed1989

Amyloid neuropathy: immunocytochemical localization of intra- and extracellular immunoglobulin light chains.

Sural nerve specimens from ten patients with amyloidosis (hereditary, associated with lymphoproliferative disorders, or of unknown origin) and peripheral neuropathy were investigated by immunohistochemistry at the light and electron microscopic level. Peroxidase-antiperoxidase and immunogold techniques were applied to glutaraldehyde-fixed, osmicated and epoxy-embedded tissue. In five cases, four of which associated with lymphoproliferative disorders, amyloid deposits strongly and exclusively reacted with antibodies to kappa or lambda light chains, respectively. By electron microscopy, bundles of immunogold-labelled amyloid fibrils could be identified in coated and uncoated single membrane-bound vesicles of endoneurial macrophages. Schwann cells did not contain intracellular amyloid but their processes were entangled in amyloid fibrils and their basement membranes were sometimes fused with the fibrillar masses. It is concluded that immunoglobulin light chains in AL (amyloid of immunoglobulin light chain origin) amyloidosis precipitate, forming amyloid fibrils, in the presence of, and presumably with the assistance of, endoneurial cells. Inefficiency of phagocytosis appears to be one of the major causes for the deleterious effects of amyloid.

Adult↗
PubMed1988

Binding of swine IgM immunoglobulins to peripheral nerve myelin sheaths in electron microscopic immunocytochemistry.

The IgM fraction of normal swine serum (NSS) was found to adhere to human peripheral nerve myelin sheaths from randomly selected neuropathies and control nerves in electron microscopic immunocytochemical assays. The reaction could be blocked by preincubation with undiluted fetal calf serum (FCS), whereas endoneurial background staining was already abolished by preincubation with 10% FCS. Only the IgM, but not the IgG or the IgA fraction of NSS adhered to peripheral nerve tissue. Such strong adherence of one of the components in an immunocytochemical assay may be a source of misinterpretation. Binding of swine IgM to human peripheral nerve myelin has not been described before and is of interest in the discussion about IgM binding to myelin-associated glycoprotein in IgM gammopathies.

Animals↗
PubMed1983

Tumor regression and other prognosticators in advanced head and neck cancers: a sequel to the RTOG methotrexate study.

The randomized Radiation Therapy Oncology Group (RTOG) Methotrexate trial in advanced squamous cancers of the head and neck has reported no control or survival benefits when the chemotherapy adjuvant was administered to patients just prior to definitive irradiation. The required data collection and outcome reporting among 146 patients bearing oral cavity primaries and 354 patients with oropharyngeal cancers has allowed a multi-variate approach seeking answers to many unresolved questions. As anticipated, the ability to control these squamous cancers is largely a function of size (T & N stage) with a superior clearance among T3-4 primaries of the oropharynx (66%) contrasted to identically staged oral cavity tumors (48%). Adjusted median survival is more than doubled to 26.6 months or 19.8 months among oral cavity and oropharynx patients respectively, when compared to the 8 month median survival when neither primary nor cervical nodes are controlled. Lymph node deposits also impact upon survival, especially among oropharynx patients where the 17.6 month adjusted median survival among N0 patients declines to 11.0 months when the primaries are associated with N3 nodes. Surprisingly, the ability to control nodel deposits of all sizes (N1, N2, or N3) is superior among oropharynx patients when compared with identical oral cavity metastases (e.g. 71.4% adjusted clearance in N3 oropharyngeal deposits versus 46.1% in N3 nodes secondary to oral cavity primaries). Adjustments for maldistribution of advanced N-stages in association with T-4 primary stage eliminated an apparent T-stage effect upon nodal clearance within both anatomic regions. Finally, the association of T and N-stage upon distant metastases was investigated, with the surprising conclusion that neither initial T nor N-stage exerts any apparent influence on the observed 10-12% occurrence. The interrelationship of these various prognostic variables is explored using the Cox and logistic models.

Carcinoma, Squamous Cell↗
PubMed1981

[Corneal damage caused by chloracetophenone].

Chloracetophenone solubilized in 1,1,1-trichlorethan was applied in different concentrations to the rabbit cornea. Applications were made to the centre of the cornea as well as to the limbal area and also in an experiment with centrallimbal burning. The ensuing stromal scarring was related to the absolute quantity of applied chloracetophenone, and burning of the limbal area seemed to be more effective than central applications.

Animals↗
PubMed1981

[Clinical aspects of tear gas burns on the cornea (author's transl)].

A report on the consequences of tear gas burns on the cornea and other extraocular and intraocular injuries sustained by 45 patients. Forty burns were caused by pistol shots, while five of the patients treated had burns from tear gas sprays. This report covers the distribution of the patients according to age and sex and described changes in central visual acuity. Differences in the type of injury according to the cause (explosive or aerosol) can be demonstrated: aerosol burns had less severe consequences. Twelve of the 45 patients were followed up.

Adolescent↗
PubMedDate not supplied

Immune-mediated neuropathy and myopathy in post-streptococcal disease: electron-microscopical, morphometrical and immunohistochemical studies.

A 22-year-old man suffered from a complete flaccid tetraparesis and an immune complex-mediated rapid progressive glomerulonephritis after group A streptococcal infection. Serum creatine kinase was excessively elevated and myoglobinuria occurred. Nerve conduction studies revealed evidence of axonal neuropathy. Recovery was satisfactory within 18 months. Sural nerve and peroneus muscle biopsies were performed in the 4th and 14th week of the disease. Light microscopy of the sural nerve showed an incipient axonal type of neuropathy in the first biopsy. Ultrastructurally, Wallerian degeneration and endoneurial inflammatory cells were present. In the muscle biopsy, few atrophic fibers and altered blood vessels without further anomalies were found. In the second sural nerve biopsy, macrophages were numerous, some of which were immunoreactive for HLA-DR, and only a few myelinated and some unmyelinated nerve fibers remained. Muscle fibers in the second biopsy showed high-grade atrophy and myofibrillar abnormalities. Immunohistochemistry revealed diffuse endoneurial immunoglobulin deposition in the first sample, while in the later biopsy specimen, deposits of IgG, and kappa and lambda light chains were visible in circumscribed endoneurial areas. Immune-mediated neuropathy and myopathy are not well-known complications of streptococcal disease. This is, to our knowledge, the first detailed report on morphological findings in muscle and nerve in such a disorder.

Adult↗
PubMedDate not supplied

Methodology for spinal neurotoxicity studies.

OBJECTIVE: To highlight the advantages and limitations of modern neurotoxicologic techniques useful in assessing neurotoxicity in spinal cord and nerve roots. METHODS: Techniques discussed include electrophysiologic and behavioral testing and, most important, neuropathologic evaluation of appropriately sampled and processed neurological tissue. References are given to details of methodologic procedures commonly used in neurotoxicity studies, and a detailed appendix is included for preparation of fixative and processing of tissue for electron microscopy. Tissue culture techniques and animal models, including dog spinal cord and rat peripheral nerve preparations, are also evaluated for their usefulness in neurotoxic testing. Background is provided describing the categories of neuropathologic change associated with several classes of known neurotoxic agents and specific neuronal processes affected by these agents. RESULTS: This information can be used to help develop a focused scientific approach to the problems associated with continuous spinal anesthesia. CONCLUSION: The use of neuropathologic methods to evaluate tissue injury is of the utmost importance in establishing the pathogenic mechanisms of injury and likelihood for repair and functional recovery.

Anesthesia, Spinal↗