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Biomedical subjects

M S Davidson

Publications and source records attributed to M S Davidson.

6 recordsLinked to original sources
PubMed1997

Differential expression of Egr-1-like DNA-binding activities in the naive rat brain and after excitatory stimulation.

Egr-1 and related proteins are inducible transcription factors within the brain recognizing the same consensus DNA sequence. Three Egr DNA-binding activities were observed in regions of the naive rat brain. Egr-1 was present in all brain regions examined. Bands composed, at least in part, of Egr-2 and Egr-3 were present in different relative amounts in the cerebral cortex, striatum, hippocampus, thalamus, and midbrain. All had similar affinity and specificity for the Egr consensus DNA recognition sequence. Administration of the convulsants NMDA, kainate, and pentylenetetrazole differentially induced Egr-1 and Egr-2/3 DNA-binding activities in the cerebral cortex, hippocampus, and cerebellum. All convulsants induced Egr-1 and Egr-2 immunoreactivity in the cerebral cortex and hippocampus. These data indicate that the members of the Egr family are regulated at different levels and may interact at promoters containing the Egr consensus sequence to fine tune a program of gene expression resulting from excitatory stimuli.

Animals↗
PubMed1976

Complement system in pneumococcal infections.

The properdin or alternate complement pathway may function as a heat-labile opsonin for pneumococci, and evidence has been sought for its activation in pneumococcal infections. Twenty-two patients had determinations of C1q, C4, properdin factor B, C3, and hemolytic complement during hospitalization for pneumococcal infection. Measurements were made during the first 36 h after admission on 16 patients and later during recovery on 16. The admission and recovery values were compared statistically with each other and with the levels of 15 normal individuals. The admission and recovery mean values were normal and nearly identical for C1q and C4, which are two early components of the classical pathway. The mean level of factor N, a properdin pathway component, was significantly depressed on admission, but the mean recovery value was normal. Admission levels for C3, a component of the late common pathway, were depressed, and recovery values were normal. Total hemolytic complement was decreased on admission, although the decrease was not significant for the patients with both admission and recovery determinations. The findings are consistent with the hypothesis that factor B is turned over rapidly, or consumed, early in pneumococcal infections; alternatively, persons with low baseline factor B levels may be particularly susceptible to pneumococcal infection.

Adult↗
PubMedDate not supplied

Glutamate-mediated transmission, alcohol, and alcoholism.

Glutamate-mediated neurotransmission may be involved in the range of adaptive changes in brain which occur after ethanol administration in laboratory animals, and in chronic alcoholism in human cases. Excitatory amino acid transmission is modulated by a complex system of receptors and other effectors, the efficacy of which can be profoundly affected by altered gene or protein expression. Local variations in receptor composition may underlie intrinsic regional variations in susceptibility to pathological change. Equally, ethanol use and abuse may bring about alterations in receptor subunit expression as the essence of the adaptive response. Such considerations may underlie the regional localization characteristic of the pathogenesis of alcoholic brain damage, or they may form part of the homeostatic change that constitutes the neural substrate for alcohol dependence.

Alcoholism↗