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Biomedical subjects

M Abeles

Publications and source records attributed to M Abeles.

At least 73 records · Page 4Linked to original sources
PubMed1982

Quantification, smoothing, and confidence limits for single-units' histograms.

In this article the relationships among firing rate, probability of firing and counts per bin are examined. It is suggested that PSTHs, autocorrelations and crosscorrelations of neuronal activity should all be expressed in units of firing rates (spikes/s), since the values obtained by such scaling are independent of bin size and of total time of measurement. A simple method for these histograms is described. Methods to compute confidence limits for PSTHs, autocorrelations and crosscorrelations are suggested. The computations are based on the null hypothesis that the spike train(s) is (are) the realization of (independent) Poisson-point process(es). The validity and the limitations of these computations methods, when applied to spike trains, are discussed. Methods to smooth out random fluctuation with little distortion of the histogram's shape are described. It is suggested that one can minimize the distortion of the histogram in the time-domain and in the frequency-domain by using a bell-shaped bin whose center point slides continuously along the histogram. The article aims at giving the potential user of the methods some insight for the meaning of the formulae. It describes in detail how the methods are applied in practice and illustrates each method by using real data from single-unit recordings.

Animals↗
PubMed1982

Role of the cortical neuron: integrator or coincidence detector?

A model was constructed of the relations between the incoming excitatory postsynaptic potentials and inhibitory postsynaptic potentials to the intracellular membrane potential fluctuations and to the firing rate of a single neuron. From this model, the strength of synapses was assessed in two ways: 1) the ability of several synchronous presynaptic spikes to initiate a postsynaptic spike, termed the synchronous gain of the synapse; and 2) the ability of several asynchronous presynaptic spikes to add a spike to the output spike train, called the asynchronous gain. It was found that for the conditions prevailing in the brain's cortex, the synchronous gain is almost always higher. It appears that the cortical neurons act as coincidence detectors, and that the appropriate code for the higher cortical functions is coincidence and not firing rate.

Action Potentials↗
PubMed1979

Eosinophilic fasciitis: a clinicopathologic study.

Eosinophilic fasciitis is a syndrome that is characterized by induration of the skin, peripheral eosinophilia, and a good clinical response to corticosteroid therapy. A skin biopsy specimen from a 69-year-old man who died four months after diagnosis of eosinophilic fasciitis showed that vessel walls in the fascia were invaded by inflammatory cells; endothelial cell proliferation appeared to lead to obliteration of the lumen. No evidence of internal organ involvement was noted at postmortem examination. These findings suggest that, although cutaneous vasculitis may play a role in this disorder, lack of visceral involvement and generally benign course of the disease dictate conservative therapy.

Adrenal Cortex Hormones↗
PubMed1978

Aseptic necrosis of bone in systemic lupus erythematosus. Relationship to corticosteroid therapy.

The relationship of corticosteroid therapy to the development of aseptic necrosis (AN) in 365 patients with systemic lupus erythematosus (SLE) was investigated. Seventeen patients (4.7%) were identified as having AN. The dosage of corticosteroids ingested during the initial period of therapy in patients with AN was tabulated and compared with that of 25 SLE control patients. There was a substantially greater dose of costicosteroids ingested in the first one, three, and six months of therapy in the patients with AN than in the control SLE group. Severity of disease and duration of therapy were not found to correlate with AN. Total corticosteroid dose was virtually identical in both groups. Thus, high initial corticosteroid dosages in patients with SLE seem to be associated with the development of AN.

Adult↗
PubMed1977

Skin immunofluorescence in infective endocarditis.

Immunofluorescent microscopy was performed on the clinically normal skin of 3 patients with infective endocarditis, 3 patients with bacteremia, and 6 normal subjects. Perivascular deposition of immunoglobulin and complement was demonstrated in two of the three patients with infective endocarditis and in none of the bacteremic or control subjects.

Adult↗
PubMed1977

Aseptic necrosis presenting as wrist pain in SLE.

Aseptic necrosis of the wrist in systemic lupus erythematosus (SLE) is not rare. In 156 patients with SLE, aseptic necrosis occurred in 11 patients, of whom 3 (27%) had wrist involvement. Onset of pain was insidious and the symptoms were thought to be related to synovitis due to SLE. An average of 11 months elapsed before aseptic necrosis was correctly diagnosed. An awareness of this possibility is important in the management of any patient with SLE who complains of wrist pain.

Adolescent↗
PubMed1977

Treatment of rheumatoid arthritis with gold.

There have been three important double-blind studies evaluating the use of gold therapy in rheumatoid arthritis. Patients treated with gold have decreased number of joints with synovitis, decreased ring size, increased grip strength, and roentgenographic evidence of arrest or decrease in the progression of skeletal lesions. If a patient with active synovitis does not respond to nonsteroidal anti-inflammatory drugs after four months of treatment, he is a candidate for gold therapy. Maintenance gold therapy has been shown to sustain clinical improvement. Patients must be monitored with appropiate laboratory tests.

Arthritis, Rheumatoid↗