Biomedical subjects
A H Harris
Publications and source records attributed to A H Harris.
Historical trends in road accident types, deaths and casualties in Western Australia.
Road accident casualties are major consumers of health service resources in Australia, using inpatient care, accident and emergency treatment and other facilities. We analysed hospitalisations resulting from road accidents in Western Australia from 1968 to 1987 to examine trends in accident types, deaths and casualties. Data from the Western Australian Health Department's Hospital Morbidity System were used. Although hospitalisations from road accidents generally decreased, they were still higher than the Australian average in 1985. The rate of decline in hospitalisations was similar to that for fatalities and was not generally related to age or sex. There was some evidence of a more rapid decline in the rate of severe injuries than in minor ones. Further steps need to be taken to reduce the number of casualties from road accidents, as road accidents represent a major public health problem in Western Australia.
Effect of prostaglandins, inositol 1,4,5-trisphosphate, and phorbol esters on radiation-induced decreases in calcium influx in rat brain synaptosomes.
Gamma irradiation (60Co) reduced KCl-stimulated voltage-dependent uptake of 45Ca2+ in rat whole-brain synaptosomes. Prostaglandins, inositol 1,4,5-trisphosphate, and phorbol esters were tested for their ability to inhibit radiation-induced decreases in calcium influx. None of the compounds tested alone completely prevented radiation-induced decreases in calcium uptake, but some drug combinations did inhibit decreases. Results suggest that radiation-induced decreases in calcium uptake are due to impairment of protein kinase C activity and mobilization of calcium by these drugs.
Epidermal growth factor receptor in human uterine tissues.
Epidermal growth factor receptor (EGFR) was studied in human endometrium and myometrium collected throughout the menstrual cycle (five follicular, five luteal specimens) by immunohistochemistry and quantitative ligand binding. EGFR was principally present on the cell surface of glandular epithelium of the endometrium. Staining was no different between the follicular and luteal phases. There was more EGFR binding in endometrium than myometrium by quantitative ligand binding in membrane preparations: endometrium, median = 92.5 fmol/mg protein (range 25.3-294) n = 10; myometrium, median = 43.0 fmol/mg protein (range 23.4-57) n = 10. There was no difference in the level of binding in the follicular and luteal phases.
Role of neurotensin in radiation-induced hypothermia in rats.
The role of neurotensin in radiation-induced hypothermia was examined. Intracerebroventricular (ICV) administration of neurotensin produced dose-dependent hypothermia. Histamine appears to mediate neurotensin-induced hypothermia because the mast cell stabilizer disodium cromoglycate and antihistamines blocked the hypothermic effects of neurotensin. An ICV pretreatment with neurotensin antibody attenuated neurotensin-induced hypothermia, but did not attenuate radiation-induced hypothermia, suggesting that radiation-induced hypothermia was not mediated by neurotensin.
Novel long-term cardiovascular effects of industrial noise.
Baboon subjects were instrumented with indwelling arterial catheters for continuous measurement of blood pressure and heart rate before, during, and after exposure to industrial noise eight hours daily. Initial exposure to noise produced transient, acute elevations of systolic and diastolic blood pressures and heart rates at noise onset, which habituated over the course of noise exposure. Chronic exposure to noise lowered blood pressure and heart rate not only during noise, but particularly after daily noise offset. Blood pressures returned toward baseline after noise exposure was terminated. Plasma catecholamines were also decreased during noise exposure. A control animal which received only masking noise did not demonstrate decreases in cardiovascular parameters. The possibility of classically conditioned associations of noise onset with feeding was discussed.
Discriminative control of hyperdipsic drinking in the baboon.
A baboon subject was surgically prepared with an arterial catheter and subsequently trained to elevate diastolic blood pressure with an operant schedule of food procurement and shock avoidance with associated discriminative stimuli. Blood pressure elevations developed in accordance with the requirements of the conditioning procedure. In addition, large-scale increases in water intake occurred on days when the conditioning sessions were in effect. Both blood pressure and water intake elevations were maintained when the conditioning procedure was changed to eliminate food reinforcement. Electrical monitoring of water spout contacts revealed that drinking occurred exclusively during response-produced SDS associated with food delivery, and did not occur either during response-produced SDS associated with electric shock, or during intertrial intervals. Because acute elevations in blood pressure preceded licking bouts, the drinking was not producing the pressor episodes. Overall, the data illustrate that drinking can occur in a systematic manner under the control of exteroceptive discriminative stimuli during non-skeletal response contingencies.
Hyperdipsia in the baboon during operant conditioning of blood pressure elevation.
Water intake was monitored in intact baboons during acquisition stages of blood pressure conditioning (Experiment 1) and during 24-hr periods (Experiment 2). Water intake was elevated during noncontingent food pellet delivery, and more so during early acquisition stages of operantly conditioned blood pressure elevations. Changes in blood pressure, heart rate, and water intake were found to correspond closely during conditioning sessions. Several possible sources of control over drinking are discussed, such as the role of food-related discriminative stimuli, and hypothalamic integration of cardiovascular hemodynamics, water ingestion, and thermal regulation.
A standard technique for haemagglutination inhibition tests for antibodies to avian infectious bronchitis virus.
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The ultrastructural localization of immunoglobulin in chronic lymphocytic lymphoma cells: changes in light and heavy chain distribution induced by mitogen stimulation.
The distribution of light and heavy immunoglobulin chains in chronic lymphocytic leukemia (CLL) cells has been investigated at the ultrastructural level using an immunoperoxidase technique. Light chains were localized in the lumens of the perinuclear space and rough endoplasmic reticulum, while staining for heavy chains was weak or negative and generally confined to the membranes of the rough endoplasmic reticulum. This pattern is consistent with immunoglobulin biosynthetic studies on CLL cells in which light chains are synthesized in excess over heavy chains and secreted as the exclusive immunoglobulin product. The pokeweed mitogen stimulation of two populations of CLL cells for 6 days resulted in a balanced synthesis and secretion of light and heavy chains that was reflected in concomitant change in light and heavy chain distribution and intensity of staining using the immunoperoxidase technique.
Plasma catecholamines and renin during operant blood pressure conditioning in baboons.
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Baroreflex sensitivity during operant blood pressure conditioning.
Baroreflex sensitivity was measured in baboons operantly conditioned to increase their diastolic blood pressure in daily, 12-hr sessions, by using the extent of increases in interpulse interval per unit of increase in systolic pressure after intravenous phenylephrine injection as an index of baroreflex sensitivity. Following training, baroreflex sensitivity increases averaging 32% were observed before and after the 12-hr conditioning sessions. During the conditioning sessions, however, consistent diastolic blood pressure elevations averaging 17% (14 mmHg) were accompanied by significant decreases in baroreflex sensitivity averaging 44% relative to the increased "before" and "after" sensitivity levels. The results suggest that changes in baroreflex sensitivity participate in operantly conditioned blood pressure changes.
Sympathetic adrenergic blockade effects upon operantly conditioned blood pressure elevations in baboons.
Sympathetic adrenergic nervous activity during operantly conditioned hypertension was evaluated by assessing the effects of specific alpha-(phentolamine or phenoxybenzamine) and beta- (propranolol) adrenergic blockers in baboons reinforced for increasing diastolic pressure in daily, 12-h sessions. In the first 10 min of control (no blockade) sessions, mean heart rate increased 24 bpm (21%) above the value for the 10 min immediately prior to the beginning of the sessions; systolic pressure increased 27 mm Hg (22%) and diastolic pressure increased 24 mm Hg (31%). Beta-blockade eliminated the tachycardia but did not attenuate the increased blood pressure. Alpha-blockade did not attenuate the increased blood pressure significantly either. Combined alpha- and beta-blockade did significantly attenuate the increase in diastolic pressure, but consistent, significant increases in systolic pressure (17 mm Hg, 17%) and diastolic pressure (16 mm Hg, 26%) still occurred. The results support the participation of the sympathetic adrenergic nervous system in producing operantly conditioned blood pressure changes, but the results are also consistent with the additional participation of nonadrenergic factors in operantly conditioned hypertension.
Psychological and physiological variables associated with large magnitude voluntary heart rate changes.
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Animal learning. Visceral and autonomic conditioning.
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Size reduction in bighorn sheep (Ovis canadensis) at the close of the Pleistocene.
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Instrumental conditioning of large-magnitude, daily, 12-hour blood pressure elevations in the baboon.
Blood pressure and heart rate were monitored continuously in four baboons during extended exposure to a daily 12-hour conditioning procedure providing food and shock-avoidance as contingent consequences of prespecified increases in diastolic blood pressure. Sustained and significant increases (30 to 40 mm-Hg) in both systolic and diastolic blood pressure were maintained throughout the daily 12-hour conditioning sessions, accompanied by elevated heart rates.
Instrumental (operant) conditioning of visceral and autonomic functions.
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