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Biomedical subjects

R Neuman

Publications and source records attributed to R Neuman.

31 records · Page 2Linked to original sources
PubMed1988

Extrahepatic tumor deposits misdiagnosed as intrahepatic metastases.

Focal hepatic lesions seen on roentgenologic evaluation of the liver in patients with cancer are usually assumed to be caused by parenchymal metastases. In this report, liver imaging tests showed six patients with filling defects caused by peritoneal carcinoma indenting the liver parenchyma. Extrahepatic tumor deposits were misdiagnosed in all but one of these cases. The roentgenographic characteristics that can assist in the differentiation of intrahepatic and extrahepatic metastases are a lens-shaped defect, a defect adjacent to the hemidiaphragm, and a halo around the liver suggesting peritoneal carcinomatosis. A high index of suspicion for extra-hepatic tumor masses causing intrahepatic filling defects may help prevent unnecessary exploratory surgery for treatment of hepatic metastases. Angiography may occasionally be helpful in distinguishing intrahepatic from extrahepatic disease.

Diagnostic Errors↗
PubMed1988

A small dose of morphine increases intake of and preference for isotonic saline among rats.

Water-deprived rats were given hourly opportunities to ingest physiological saline and water for a number of days until they were taking substantial amounts of both solutions. Prior to some opportunities to ingest, they were injected with either morphine (2.0 mg/kg) or a placebo. Across a variety of procedures, morphine increased intake of and, in 1-hr tests, increased preference for 0.9% NaCl. Intake of 1.5% NaCl also increased after administration of morphine. These data suggest that endogenous opioids are involved in sodium intake. These data also provide further support for the idea that one or more of the endogenous opioid systems are involved in the regulation of ingestion.

Animals↗
PubMed1987

Is activation of N-methyl-D-aspartate receptor gated channels sufficient to induce long term potentiation?

Superfusion of hippocampal slices with Mg2+ free medium (20-30 min) produced in CA1 interictal bursts and an enhancement of the Schaffer collateral synaptic response which persisted for over 2 h after return to control media. This long lasting effect, which was blocked by N-methyl-D-aspartate (NMDA) antagonists, was not associated with changes in postsynaptic cell excitability. A cut between CA3 and CA1, which blocked the bursts in CA1 (but not in CA3), also abolished the long lasting effects of Mg2+ free medium. It is concluded that the activation of NMDA receptors gated ionic channels is insufficient per se to induce a long term potentiation of synaptic transmission.

Action Potentials↗
PubMed1976

Hepatic cholesterol-7alpha-hydroxylase activity in neurogenic hypercholesterolemia.

The cholesterol-7alpha-hydroxylase activity of hepatic microsomal preparations of hypothalamic hypercholesterolemic rats and normal rats was assayed in rats fed diets high and low in cholesterol, and in rats killed at the supposed height and at the nadir of the diurnal cycle of enzyme activity. The activity of this enzyme system appeared to be unimpaired in the hypothalamic hypercholesterolemic rat.

Animals↗
PubMedDate not supplied

Neurogenic hypercholesterolemia: influence of autonomic drugs.

Eleven substances capable of either augmenting or depleting the alpha- and - beta-adrenergic capacities of the autonomic nervous system were administered to rats exhibiting hypothalamic hypercholesterolemia and to normal controls. Only the beta-adrenergic blocking agents propranolol and possibly 6-OH dopamine were observed to alter (raise) the serum cholesterol concentration, and this occurred in both experimental and control animals. Neither atropine, nor the serotonin-depleting agent, rho-chlorophenylalanine, nor the serotonin-antagonist cyproheptadine, were observed to alter serum cholesterol level. Such absence of effect was also noted with metaraminol, phenoxybenzamine, isoproterenol, epinephrine, reserpine, and alpha-methyl tyrosine.

Adrenergic alpha-Agonists↗
PubMedDate not supplied

Further studies of opioids and intake of sweetened alcoholic beverage.

Rats were placed on a daily regimen of water deprivation followed by a limited opportunity to take either water or a sweetened alcoholic beverage. Across days of opportunity, they took less water and more alcohol until they were taking considerable amounts of alcohol. Naloxone, the classic antagonist at opioid receptors, was given prior to opportunity to drink and it reduced intakes of alcoholic beverage. Small doses of morphine, the classic agonist, increased intakes of alcoholic beverage at doses as low as 0.41 mg/kg. The effects of two other antagonists at opioid receptors (LY117413 and MR2266) were also tested. Both reduced intakes of alcohol. The data showing that more than one or two opioid antagonists reduce intakes of alcoholic beverages, even palatable beverages usually taken in large amounts, and that morphine increases intakes at very low doses, strengthen the idea that endogenous opioid systems are involved in modulating intake of alcohol.

Alcohol Drinking↗
PubMedDate not supplied

Investigations concerning the action of serveral chemical and biological agents on HBsAg.

Native and purified HBsAg preparations were subjected in vitro to the action of cetylpyridinium bromide (Bromocet), hibitan-chlorhexidine (Hibiscrub), chloramine B and propolis extract, at different concentrations and for various time intervals. The effect of these agents on the serological reactivity of HBsAg was tested by electroimmunodiffusion (EID) and radioimmunoassay (RIA). Chloramine B and the propolis extract had a significant inhibitory effect-ascertained by both EID and RIA - on purified HBsAg, but not on the native preparation. The inhibition exerted by Bromocet and Hibiscrub indicated by EID results was not confirmed by RIA.

Cetylpyridinium↗