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Biomedical subjects

J L Ferguson

Publications and source records attributed to J L Ferguson.

80 records · Page 5Linked to original sources
PubMed1978

Dexamethasone treatment during hemorrhagic shock: effects independent of increased blood pressure.

Effects of dexamethasone (5 mg/kg of body weight) on organ blood flow, enzyme release, and hemodynamics were studied in dogs with hemorrhagic shock to determine if the consequences observed were due to increased mean arterial blood pressure (MABP) or intrinsic effects of dexamethasone. Hemorrhage was induced in anesthetized dogs until the MABP was 50 mm of Hg and then the dogs were treated with dexamethasone or an equal volume of saline solution. Dogs remained connected to the blood reservoir during the entire experiment and MABP was maintained at 50 mm of Hg in the treated and control groups of dogs. Beneficial actions of dexamethasone treatment independent of increased MABP were observed. Increased survival rate, differential blood flow to some organs, and less tissue damage occurred as a result of dexamethasone treatment and were independent of increased MABP.

Amylases↗
PubMed1977

Regional blood flow redistribution during early burn shock in the guinea pig.

The distribution of blood flow was determined with radioactive microspheres following scald injury in guinea pigs. Burn was induced in halothane-anesthetized guinea pigs by a 3-sec immersion to the xiphoid process in 100 degree C water. Cardiac output and fractional blood flow measurements were made at preburn, 15-min postburn, and 75-min post-burn. In the scalded animals cardiac output decreased 58% by 75 min postburn. Three different blood flow responses to burn were noted: a) Brain, heart, hepatic artery, and adrenals received an increased fraction of the cardiac output; b) the fractional distribution of the diaphragm, liver (portal), spleen, gastrointestinal tract, muscle (from burned portion of the body), and bone remained constant; while c) the pancreas, burned skin, nonburned skin, and adipose tissue received a reduced fraction of the cardiac output. Although some regions of the body (i.e., brain and heart) received a greater percentage of the total cardiac output after burn injury, the cardiac output decrease was sufficient to cause a depression in absolute blood flow to all but two sites (adrenals and hepatic artery).

Animals↗
PubMedDate not supplied

Progressive behavioral changes during the maturation of rats with early radiation-induced hypoplasia of fascia dentata granule cells.

Localized exposure of the neonatal rat brain to X-rays produces neuronal hypoplasia specific to the granule cell layer of the hippocampal dentate gyrus. This brain damage causes locomotor hyperactivity, slowed acquisition of passive avoidance tasks and long bouts of spontaneous turning (without reversals) in a bowl apparatus. Here we report how these behavioral deficits change as a function of subject aging and behavioral test replications. Portions of the neonatal rat cerebral hemispheres were X-irradiated in order to selectively damage the granule cells of the dentate gyrus. The brains of experimental animals received a fractionated dose of X rays (13 Gy total) over postnatal days 1 to 16 and control animals were sham-irradiated. Rats between the ages of 71-462 days were tested 3 separate times on each of the following 3 behavioral tests: 1) spontaneous locomotion, 2) passive avoidance acquisition, and 3) spontaneous circling in a large plastic hemisphere. Rats with radiation-induced damage to the fascia dentata exhibited long bouts of slow turns without reversals. Once they began, irradiated subjects perseverated in turning to an extent significantly greater than sham-irradiated control subjects. This irradiation effect was significant during all test series. Moreover, in time, spontaneous perseverative turning was significantly potentiated in rats with hippocampal damage but increased only slightly in controls. Early radiation exposure produced locomotor hyperactivity in young rats. While activity levels of controls remained fairly stable throughout the course of the experiment, the hyperactivity of the irradiated animals decreased significantly as they matured.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗