Biomedical subjects
Publications and source records attributed to D E Pleasure.
Erythrocyte calcium transport as a function of free [Ca++] was examined using inside-out vesicles from eight pairs of patients with Duchenne dystrophy and age- and sex-matched controls. The Km for Ca++ of the transport protein and the Vmax were higher in the Duchenne vesicles in seven of the eight pairs. The mean Km and Vmax were significantly higher in the Duchenne group.
Antisera raised in rabbits against galactocerebroside bind to bovine oligodendroglia in suspension in significant titer as demonstrated by indirect immunofluorescence. Absorption of antigalactocerebroside antiserum with galactocerebroside, oligodendroglia, or myelin markedly reduces the antigalactocerebroside antibody titer as measured by a radioimmunoprecipitation test as well as the binding to oligodendroglia. Incubation with some other galactose-containing glycolipids results in a parallel decrease in binding to oligodendroglia and reduction in antigalactocerebroside antibody titer. Antigalactocerebroside antibodies provide a useful and specific tool with which to study development of oligodendroglia and myelin as well as immunopathologic mechanisms which might be involved in demyelinating diseases.
Explants from newborn mouse cerebellum were cultured in nutrient media containing either adequate (30%) or low (15% or 7.5%) serum content. By light microscopic observation, delayed and inhibited myelination was detected in cultures fed with low serum media (experimental cultures). Specific activities of two enzymes related to myelin synthesis, 2',3'-cyclic nucleotide-3'-phosphohydrolase and 3-hydroxy-3-methylglutaryl coenzyme A reductase, were also reduced in experimental cultures. Morphometric analysis of electron micrographs showed that the size of presynaptic endings and total area occupied by synapses in experimental cultures were substantially reduced, while synaptic density per unit area increased. Reflecting the results of synaptic underdevelopment, the levels of two neurotransmitter enzymes, choline acetyltransferase and glutamic acid decarboxylase, were also decreased in experimental cultures.
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Cell-mediated immunity to myelin basic protein, to an extract of central nervous system white matter, and to measles virus nuclear core, was studied nine patients with multiple sclerosis in a serial longitudinal fashion using in vitro inhibition of buffy coat migration. The mean migration index to all antigens at various times before, during, and after exacerbation of multiple scelrosis in the patients did not differ from the index in a reference group of normal subjects. The incidence of inhibition of migration induced by central nervous system white matter and basic protein was greater than in serially studied normal subjects (p less than 0.05, p less than 0.2 less than 0.1, respectively) but bore no definite relation to clinical course.
We demonstrated antibodies to isolated oligodendrocytes and to oligodendroglia in brain sections by indirect immunofluorescence technic in serums of 19 of 21 patients with multiple sclerosis. We also found such antibodies in three of five patients with subacute sclerosing panencephalitis and one of four patients with acute disseminated encephalomyelitis, but not in patients with other neurologic diseases or normal persons. The antibodies were absorbed by preincubation of serum with isolated oligodendrocytes or whole white matter, but not with purified myelin or liver tissue. Immunofluorescent staining was blocked by either rabbit anti-oligodendrocyte serum or non-fluoresceinated goat anti-human immunoglobulin. These findings suggest that antibodies to oligodendroglia are distinct from antibodies to myelin and that demyelination in multiple sclerosis could be a consequence of an immunopathologic reaction directed against oligodendroglial cells.
Adult rats given high orally administered doses of triethyltin (TET) sulfate lost weight, developed hind limb wasting, and became paraplegic or quadriplegic within three weeks of intoxication. A 33% reduction in the motor nerve conduction velocity (MNCV) of the sciatic nerve in the absence of significant demyelination was observed. There was observed, however, intramyelinic edema formation and an increased number of axonal neurofilaments and neurotubules; changes that paralleled the decrease in MNCV during the period of intoxication. Although the animals became asymptomatic and the MNCV normalized within two to three weeks of discontinuing the TET intoxication, the intramyelinic vacuoles and the increased numbers of neurofilaments and neurotubules persisted.
Peripheral nerve is a complex tissue composed of endoneurial fascicles surrounded by perineurium and epineurium. We separated endoneurium from peri- and epineurium in human sural nerves by "endoneurial plucking", a method of microdissection. Endoneurial contents (axons, myelin sheaths, Schwann cells, vessels, and interstitial collagen) were cleanly separated in high yield from enveloping connective tissue, by both microscopic and biochemical criteria. Most of the nerve sulfatide and unesterified sterol was found in the endoneurial fraction while most of the collagen was in the peri-epineurial fraction. This microdissection method should prove useful in biochemical investigations of peripheral nerve.
The effectiveness of epineurial, perineurial, and a combined epiperineurial methods of nerve suture in the severed sciatic nerve of rabbits was studied by biochemical assay of the collagen just distal to the neuroma and the collagen and myelin of the posterior tibial nerve. Repairs were done both immediately after severance and in a separate group 3 weeks later. More collagen was found near the neuroma in the immediate epineurial group, but 60 per cent of the normal myelin was found in the posterior tibial nerve after the immediate epineural suture compared to 28.3 per cent in the immediate perineurial group.
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Axoplasmic flow of proteins is interrlupted in cats with neuropatlhy induced by acrylamide, but it is niot initerrupted in nzormlal cats and in those with neuropathy induced by tri-orthocresyl phiospliate. The proteins move from lumbosacral motor neurons along the ventral roots and from ganglion cells toward the spinal cord along the dorsal roots at about 1(1/2) millimeters per day.
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