Biomedical subjects
S Magge
Publications and source records attributed to S Magge.
Molecular biology of axonal outgrowth. 2. Pathfinding and molecular guidance cues.
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Cranial plate and screw fixation in infancy: an assessment of risk.
Sixty-seven surgeons, members of the International Craniofacial Surgery Society, responded to a questionnaire focused on assessing the incidence and risk of cranial plate and screw translocation intracranially in infants undergoing cranial surgery. Despite screws, plates, and wires being evident intracranially in individual cases, no apparent increase in seizure frequency or susceptibility to head trauma was noted in this preliminary study.
Human epileptic astrocytes exhibit increased gap junction coupling.
Fluorescence Recovery After Photobleach (FRAP) was used to quantify astrocyte gap junction coupling from tissues surgically resected from medically intractable epilepsy patients. Mesial temporal lobe cases provided hippocampus, surrounding hyperexcitable parahippocampus and normal cortex for culture. Cortical tumor cases yielded astrocytoma proper, cortex margins with normal EEG activity, and hyperexcitable cortex. Cells isolated from cortex surrounding astrocytomas and the parahippocampus surrounding the hippocampus showed an increase in glutamate-induced Ca2+ oscillations and intercellular Ca2+ waves. Gap-junction coupling was more pronounced in cells isolated from hyperexcitable tissue than from normal tissues as judged by their faster and more complete fluorescence recovery from laser bleach [FRAP]. This data suggests that intractable epilepsy may be associated with alterations in glial gap junction coupling.
Insulin-mediated post-transcriptional regulation of hepatic malic enzyme and albumin mRNAs.
Livers of insulin-treated diabetic rats accumulate albumin and malic enzyme mRNAs at very different rates. We now report that in normal rats insulin directs a specific increase in malic enzyme mRNA, while albumin mRNA levels remain unaltered. These studies support the contention that insulin regulates the accumulation of hepatic mRNAs in a highly specific manner. To evaluate whether or not albumin and malic enzyme mRNA levels are determined by altered rates of transcription, in vitro transcription assays were performed. The results of these studies demonstrate that increased malic enzyme mRNA levels in insulin-treated normal rats and increased malic enzyme and albumin mRNA levels in insulin-treated diabetic rats do not involve altered rates of transcription of the genetic sequences encoding these proteins. For these two specific proteins, insulin mediates changes in mRNA levels by a post-transcriptional mechanism.
Synovial lymphocyte response to chlamydial stimulation associated with intrasynovial chlamydial antigen in a patient with "rheumatoid arthritis".
A 48-year-old man with "rheumatoid arthritis" of 3 years duration was found to have synovial fluid lymphocytes that were maximally stimulated in vitro by chlamydial antigen, on 5 of 6 tests over 18 months. Immunocytochemical staining of a synovectomy specimen, using the peroxidase-antiperoxidase technique, subsequently revealed chlamydial antigen in the synovium. The possibility that Chlamydia in the synovium may produce features of rheumatoid arthritis is discussed.
Light and electron microscopic studies on the synovial membrane in Reiter's syndrome. Immunocytochemical identification of chlamydial antigen in patients with early disease.
Studies by light microscopy on synovium obtained from 11 patients with Reiter's syndrome during the first month of an episode showed proliferation of synovial lining cells, polymorphonuclear neutrophils among the synovial lining cells, increased surface fibrin, and vascular congestion. Biopsy specimens taken later showed vascular congestion and still proliferated synovial lining cells, fewer polymorphonuclear neutrophils in some, and a tendency toward increased infiltration with lymphocytes and plasma cells. Electron microscopy of samples from 8 patients during the first month of disease activity showed occlusion of vessels by platelets in 4, and fibrin or dense granular material in the vessel walls in 4. Five of the patients with arthritis of less than 4 weeks duration had unidentified intracellular and extracellular particles; some of these were highly suggestive of Chlamydia. No such particles were noted in samples from patients with more chronic cases. Using an antibody to Chlamydia trachomatis and the peroxidase-antiperoxidase technique, immunocytochemistry showed reaction product in synovial macrophages in 2 patients with arthritis of less than 4 weeks duration, but not in the 1 patient studied who had more chronic disease. These studies provide support for dramatic synovial vascular injury consistent with that caused by endotoxin and the presence of chlamydial antigen in synovial macrophages, at least in the early phases of synovitis.