Biomedical subjects
Publications and source records attributed to P Lampert.
Treatment of SJL/J mice with myelin components prior to infection with Theiler's picornavirus did not effect the development of inflammatory demyelinating lesions characteristic of Theiler's mouse encephalomyelitis. These results suggest that the pathogenesis of this disease differs from experimental autoimmune encephalomyelitis, which can be suppressed by such a treatment.
Molecular hybridization, monoclonal antibody, and electron microscopic analyses showed lymphocytic choriomeningitis virus (strains Armstrong and WE) persistently infecting cells of the islets of Langerhans in BALB/WEHI mice. When monoclonal or monospecific antibody conjugated with two different fluorochrome dyes was used to mark insulin-containing beta cells or viral antigens, viral nucleoprotein was identified predominantly in beta cells. Electron microscopy confirmed these findings by showing virions budding from the beta cells. Persistent infection was associated with chemical evidence of diabetes (hyperglycemia, abnormal glucose tolerance, and normal or low-normal concentrations of insulin). Concentrations of cortisol and insulin-like growth factor in blood were normal, as was the level of growth hormone in the pituitary gland. The virus-infected islet cells showed normal anatomy and cytomorphology. Neither cell lysis nor inflammatory infiltrates were routinely seen. Thus a virus may persistently infect islet cells and provide a biochemical and morphological picture comparable to that of early adult-onset diabetes mellitus in humans.
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Patterns of demyelination were studied in sciatic nerves, spinal roots and ganglia of chickens afflicted with either Marek's disease (MD) or experimental allergic neuritis (EAN). MD was induced in susceptible chicks after hatching by inoculation of the JM strain of MD Herpes virus. Tissues from these chickens were examined 7-83 days after infection. EAN was studied 10-21 days after sensitization of 4 week old chickens to emulsions containing human peripheral nerve with complete Freund's adjuvant. In both conditions lesions were encountered which consisted of perivenular infiltrates of mononuclear cells that penetrated the basal lamina of the neurolemmal sheath, displaced Schwann cells, lysed and stripped myelin lamellae without damage to axons. Other lesions in MD were characterized by lymphomatous infiltrates that contained necrotic cells and disintegrating axons. The similarity of the demyelinating process in MD to that seen in EAN suggests that MD virus infection activates lymphocytes sensitized to peripheral nerve myelin. The findings are discussed with reference to acute idiopathic polyneuritis (Guillain-Barré syndrome) in patients with preceding or concurrent Herpes virus infections including those known to cause lymphoproliferative disorders.
Mice injected intraperitoneally with 20 mg of ferritin twice weekly for more than 4 weeks developed proteinuria due to the deposition of ferritin-antiferritin antibody complexes in renal glomeruli. Deposits of ferritin, immunoglobulin G (IgG) and third complement component (C3) also accumulated in the perivascular, extracellular space of the choroid plexus as demonstrated by immunofluorescence and electron microscopy. The findings confirm previous observations on immune complex deposits in the choroid plexus in spontaneous autoimmune disease and persistent viral infections. The occurrence of similar deposits in the human choroid plexus and the possibility of an associated disturbance of the blood-spinal fluid barrier are discussed.
A sural nerve biopsy was performed on an 8-year-old boy with a chronic, slowly progressive polyneuropathy. Light and electron microscopy as well as teased nerve-fiber preparations demonstrated numerous giant axons filled with closely packed neurofilaments. Both myelinated and unmyelinated fibers were involved. Segmental demyelination, remyelination, and onion-bulb formation by multiple Schwann cell processes were observed, suggesting recurrent Schwann cell dysfunction. Abundant aggregates of cytoplasmic microfilaments occurred in Schwann cells, endothelial cells, perineurial cells, endoneurial fibroblasts, and endomysial fibroblasts. These findings support the proposal that giant axonal neuropathy is a generalized disorder of cytoplasmic microfilaments and that segmental demyelination occurs concomitantly with axonal and Schwann cell disease. The pathogenesis of this rare disorder is discussed with reference to experimental toxic neuropathies.
Peripheral nerves of diabetic rats were studied 2 years after alloxan injection. We observed demyelination and remyelination, axonal degeneration and regeneration, reduplication of basal laminae around vessels and Schwann's cells, as well as onion bulb formation by proliferated Schwann's cells. Crystalline deposits composed of aggregates of fibrillary electron dense material often occurred in vessel walls and endoneurium of diabetic animals but rarely were seen in nerves from age-matched control animals. Glycogen accumulated in myelinated and unmyelinated axons within mitochondria. Axoplasmic inclusions resembling Lafora's bodies and the inclusions of glycogenosis type IV were frequent and often were accompanied by deposits of particulate glycogen. The findings suggest that the neuropathy in alloxan diabetes is caused by metabolic impairment of anxons, Schwann's cells, and vessels, leading to segmental demyelination and axonal degeneration.
Ultrastructural and neurochemical studies were done on three male patients with adrenoleukodystrophy. In each case, the affected white matter contained enlarged glial cells filled with pathognomic intracytoplasmic inclusions consisting of electron-lucent spicules bounded by 25-Angstrom wide membranes. Similar inclusions were present in adrenocortical cells. These findings and a review of 47 reported cases indicate that adrenoleukodystrophy is a storage disorder caused by a sex-linked recessive error of metabolism.
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