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Biomedical subjects

M Brownstein

Publications and source records attributed to M Brownstein.

At least 55 records · Page 3Linked to original sources
PubMed1978

Identification of insulin in rat brain.

Insulin concentrations in acid/ethanol extracts of the whole rat brain were on the average 25 times higher than plasma insulin levels. Brain insulin was indistinguishable from authentic pancreatic insulin, based on its behavior in radioimmunoassay, radioreceptor assay, and bioassay and its chromatographic pattern on Sephadex G-50 column chromatography. Insulin was found in all regions of the brain examined, but distribution was uneven. Some regions had insulin concentrations as much as 100 times higher than in plasma; levels at least 10 times higher were found in other regions. The role of insulin in the central nervous system is not clear at present but, because both insulin and insulin receptors are abundant in the central nervous system, an extensive physiological regulation of the central nervous system by insulin is proposed.

Adipose Tissue↗
PubMed1978

Replacement of damaged arteries and veins with vein grafts when replanting crushed, amputated fingers.

Two cases are presented in which multiple vein grafts were used to revascularize several digits in hands injured by severe crushes. One case had partial amputations of 4 digits, and the other had 4 complete amputations. After debriding the damaged parts of the vessels, we interposed vein grafts in both the arterial and venous circulations to the digits. Seven of 8 revascularized digits survived. In crushing injuries, it is essential to debride the vessels proximally and distally to where the intima has not been injured. To bridge the gaps, vein grafts can be used successfully where other methods are undesirable or impossible.

Adolescent↗
PubMed1976

Effect of stress on serotonin concentration and tryptophan hydroxylase activity of brain nuclei.

The effects of a single stressful stimulus on serotonin (5-HT) concentration and of repeated stressful stimuli on tryptophan hydroxylase (THy) activity were measured in individual hypothalamic nuclei and other rat brain regions using specific sensitive radioisotopic enzymatic microassays. Two h after formalin injection, 5-HT levels were increased in the dorsal raphe (RDN). Acute immobilization stress, however, reduced the concentrations of 5-HT in several of the hypothalamic nuclei: the medium eminence (ME), lateral amygdaloid nucleus, hippocampus, cingulate cortex (CCX) and RDN. Five consecutive daily immobilization periods failed to alter THy activity in any region examined. These results suggest a rapid release of 5-HT both from the cells and the axon terminals in the central nervous system, and failure, even with repeated stresses, to elicit induction of increased levels of the biosynthetic enzyme regulating the synthesis of the neurotransmitter.

Animals↗
PubMed1975

The effect of two diverse inhalation anesthetic agents on serotonin in discrete regions of the rat brain.

Sensitive radioisotopic enzymatic methods were used to determine 5-HT levels in 16 different regions of brain from rats anesthetized for 90-105 min with 1% halothane or 18% cyclopropane. These two anesthetics were chosen because of their differing effects on the electroencephalogram and on the cardiovascular and respiratory systems. 5-HT levels in the nucleus amygdaloideus centralis, substantia nigra, and nucleus centralis superior were increased after administration of either anesthetic, but only anesthesia with cyclopropane was associated with an increase in 5-HT level in the nucleus raphe dorsalis. The changes in levels of transmitter does not distinguish cause from effect of anesthesia, and further experiments are needed to delineate what role, if any, the specific areas play in muscle relaxation, analgesia, sleep or anesthesia.

Amygdala↗
PubMed1975

The regional distribution of somatostatin in the rat brain.

A sensitive and specific radioimmunoassay for somatostatin (SRIF) has been used to determine the regional distribution of SRIF in rat brain. The hypothalamus contained the highest concentration of SRIF. Lower, but significant amounts of SRIF were present outside of the hypothalalmus. Within the hypothalamus, the concentration of SRIF was highest in the median eminence and arcuate nucleus although all of the hypothalmic nuclei contained some fo this material. The implications of this distribution are discussed.

Animals↗
PubMed1974

Pineal gland: 24-hour rhythm in norepinephrine turnover.

There is a 24-hour rhythm in the turnover of norepinephrine in sympathetic nerves innervating the pineal gland. This rhythm persists in blinded animals but is suppressed in normnal rats by light. The rhythm in norepinephrine turnover generates the rhythums in pineal indoleamines and N-acetyltransferase.

Acetyltransferases↗