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Biomedical subjects

M Wallace

Publications and source records attributed to M Wallace.

At least 163 records · Page 9Linked to original sources
PubMed1988

Black Americans' perceptions of cancer. A study utilizing the Health Belief Model.

The purpose of this study was to determine black adults' knowledge and perceptions of cancer by utilizing the Health Belief Model. The subjects were obtained by randomly selecting 11 churches from a list of 33. There were 769 black adults who responded to the survey (64 percent response rate). Mean age of respondents was 44.3 years, SD = 14.7. Only 29 percent were able to correctly identify all seven of the American Cancer Society warning signs; 13 percent were unable to identify any warning signs. One in four believed it was likely they would develop cancer sometime in their life, and 42 percent believed blacks were more susceptible to cancer than whites. Forty-one percent believed most people who get cancer will die from it. Perceived barriers to treatment included cost and pain. A large number of significant differences (P < .01) were found when responses were examined in relation to the sex, educational level, and age of the subjects.

Adult↗
PubMed1987

Effect of treatment setting on social workers' knowledge of psychotropic drugs.

Because the use of psychotropic drugs is a part of treatment in a variety of settings, social workers may find it helpful, if not necessary, to be knowledgeable about such medication. The study reported here explored social workers' knowledge of and attitudes toward psychotropics and concluded that treatment setting had an observable impact on both variables.

Attitude↗
PubMed1986

Molecular genetics of Huntington's disease.

The discovery of a DNA marker linked to the HD gene has provided new avenues into the investigation of this devastating disorder. Genetic investigations have determined that in most and possibly all HD families, the disease is caused by a defect that maps near the telomere on the short arm of chromosome 4. DNA markers will soon provide presymptomatic diagnosis for this disorder, but this increased capability may be a mixed blessing in the absence of effective treatment. The most hopeful route to developing such treatment lies in cloning and characterization of the primary defect. Precise genetic and physical mapping using DNA markers and improvements in techniques for analyzing large segments of DNA have set the stage for cloning of the disease gene in the near future. It will undoubtedly reveal an interesting mechanism for complete phenotypic dominance in man for comparison with completely dominant mutations in other species, particularly Drosophila. The nature of the defect may provide new insights into the functional organization of the central nervous system. For the sake of the many individuals who are afflicted by HD or who are asymptomatic gene carriers, it is to be hoped that cloning and characterizing the disease gene will also yield the necessary information to develop an effective therapy.

Chromosome Mapping↗
PubMed1986

Francisella tularensis infection in captive, wild caught prairie dogs.

An adult, wild caught prairie dog was found dehydrated and ataxic, with severe diarrhea. Gross necropsy lesions consisted of scattered pinpoint white foci throughout the liver and spleen. A massive, purulent bronchopneumonia was found also. Direct fluorescent antibody tests and culture of spleen and liver samples confirmed a diagnosis of tularemia.

Animals↗
PubMed1984

Synergistic activation of rat hepatocyte glycogen phosphorylase by A23187 and phorbol ester.

The combination of 1.6 microM 4 beta phorbol, 12 beta myristate, 13 alpha acetate (PMA) and 1 microM A23187 produced a five-fold greater stimulation of rat hepatocyte glycogen phosphorylase activity than was seen with PMA alone. Vasopressin activation of glycogen phosphorylase was comparable to that seen with PMA plus A23187. Glycogen phosphorylase activity due to PMA plus A23187 was increased significantly after 30 sec, maximal at 120 and sustained at elevated levels for 240 sec. In contrast, activation due to vasopressin was maximal at 30 sec followed by a decrease. The addition of PMA 5 min prior to the A23187 abolished the synergism between these two agents. These data are compatible with the hypothesis that diacylglycerol and Ca2+ synergistically increase glycogen phosphorylase activity in rat hepatocytes.

Animals↗
PubMed1984

Schedule-induced behavior in hyperactive children.

A schedule-induced behavior paradigm was used to investigate the activity patterns of hyperactive children in a standardized situation. In Experiment I, 10 hyperactive and 10 normal control children matched for age, sex, and IQ were observed under conditions of baseline and schedule. Measures of a number of categorized activities were taken on a time-sampling basis. Hyperactive children were more active than controls in baseline and did not respond to the schedule, unlike the controls who became significantly more active in schedule conditions. In Experiment II, 12 hyperactive and 6 normal children were again subjected to the same experimental paradigm, but in two of the four experimental sessions the stimulant drug methylphenidate was administered in an attempt to reduce the amount of baseline activity. Results were substantially similar to those of Experiment I, with hyperactive children more active than controls in baseline and insensitive to the schedule. There was no overall effect of drug administration on the behavior of either group. There were some rate-dependent effects of both drug and schedule conditions.

Attention Deficit Disorder with Hyperactivity↗
PubMed1984

Effects of 6-OHDA lesions in the nucleus accumbens on the acquisition of self injection of heroin under schedule and non schedule conditions in rats.

Acquisition of heroin self injection is enhanced in bodyweight reduced rats if a non contingent food delivery schedule is operating (schedule-induced self injection). Dopamine depletion of the nucleus accumbens septum (NAS) reduces nicotine self injection and a number of other schedule-induced behaviours. In the present experiment 6-OHDA lesions in the NAS significantly reduced the levels of heroin self injection in 7 rats on a food delivery schedule compared with sham lesioned controls. The reduced heroin intake did not differ from that of lesioned or sham lesioned rats with no schedule present. The results confirm previous reports that intact dopaminergic neurones in the NAS are necessary for schedule-induced behaviours to occur, and demonstrate that components of the same behaviour which are not schedule-induced can continue without disruption in the presence of the lesions.

Animals↗
PubMed1984

Resistance of schedule-induced behaviours to hippocampal lesions.

It has been reported that electrolytic lesions of the hippocampus accelerate the onset of schedule-induced drinking (SID) and also lead to significant increases in adrenal weights [2]. In the present experiment three groups of Long Evans rats received electrolytic or 6-Hydroxydopamine or sham lesions of the hippocampus and one group received electrolytic cortical lesions. Half of each group were tested 1 hr/day for 10 days under scheduled food delivery and the other half received food in a single presentation. It was found that both electrolytic hippocampal and cortical lesions reduced the level of SID compared with sham and 6-Hydroxydopamine lesions which did not differ from each other. However, there is support for the suggestion that hippocampal catecholamine neurones are involved in corticosterone regulation as shown by a significant increase in plasma corticosterone levels in non-scheduled, 6-Hydroxydopamine lesioned rats.

Animals↗
PubMed1984

Schedule-induced self injection of drugs.

The schedule-induced polydipsia paradigm has been used to induce oral ingestion of large volumes of alcohol, barbiturate and other drug solutions. We have developed a method of schedule-induced self injection which allows the study of acquisition and maintenance of drug intake behaviour in changing environments free from the interference of taste factors or imbalances due to excessive water intake. In this paper we review our findings on the acquisition and maintenance patterns of amphetamine, methadone, heroin, alcohol, nicotine, cocaine, delta 9-THC and haloperidol . For all drugs except amphetamine, the combination of schedule and nutritional deprivation leads to the highest rates of drug intake although the schedule does not appear to be a potent factor at free feeding weight. Drug intake is the result of the interaction of environmental factors and pharmacological properties of the drugs, rather than the effects of drug or environmental factors separately . From a number of preliminary studies, data on corticosterone response in drug self-injection behaviour and the function of the nucleus accumbens septum are presented.

Alcoholism↗
PubMed1984

The effect of naloxone on schedule-induced and other drinking.

A dose-response study of the effect of naloxone on schedule-induced drinking confirmed that this type of drinking is resistant to the opiate antagonist at doses which depressed drinking induced by water-deprivation, hypertonic saline and salbutamol. Naloxone also failed to reduce intake of saline solution in the presence of scheduled food presentation. The findings support the suggestion that schedule-induced drinking is regulated by a system of neural control which differs from that involved in deprivation and other forms of drinking. It would appear that opiate receptors do not play a part in the regulation of schedule-induced drinking.

Albuterol↗
PubMed1984

Study of the ductal epithelial cell component of human labial salivary glands in vitro.

Salivary gland cultures were propagated from primary explant cultures of 55 human labial gland biopsies. Cultures were maintained for at least 7 days in 199 medium plus 20% newborn calf serum and growth measured at this time both by cell counting and planimetry of the area. Ductal cell population identification was undertaken on the basis of an intra-cellular function, the latter being the histochemical detection of the enzyme 11 beta-hydroxysteroid dehydrogenase. Epithelioid cell lines were derived by enzymatic and mechanical means. Non-invasive quantitation of the proportion of ductal epithelial cells present in primary explant cultures, and derived cell lines, was attempted using a radioimmunoassay to detect conversion in the media of cortisol to cortisone. The cell lines were terminated after undergoing 18 passages over 20 weeks. By this time the epithelioid morphology of cells could no longer be equated to a differentiated epithelial cell origin since conversion of cortisol to cortisone in the growth media no longer occurred.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1984

Alpha 1-adrenergic stimulation of phosphatidylinositol turnover and respiration of brown fat cells.

The alpha-adrenergic agonist phenylephrine (in the presence of the beta-adrenergic antagonist alprenolol) stimulated respiration and incorporation of [3H]glycerol and [32P] Pi into phosphatidylinositol of hamster brown fat cells in a concentration-dependent manner. Both responses were preferentially inhibited by prazosin as compared with yohimbine, indicating alpha 1 specificity. Uniquely, prazosin inhibition of phenylephrine-stimulated phosphatidylinositol metabolism had two components, since 30% of the response was inhibited by less than 1 nM prazosin, 10 nM gave no further inhibition, and 100 nM prazosin completely inhibited the response. The phosphatidylinositol response was still present in Ca2+-free buffer, although reduced in magnitude. The concentration relationships of the effects of agonists and antagonists were compared with those of previous results of [3H]prazosin binding and with phenylephrine potency to compete for binding. On the basis of these comparisons, it is suggested that the highly prazosin-sensitive part of the phosphatidylinositol response may be closely associated with receptor occupation.

Adipose Tissue, Brown↗
PubMed1983

Increased weight gain and reduced activity in brown adipose tissue produced by depletion of hypothalamic noradrenaline.

The effects of hypothalamic noradrenaline depletion produced by injection of 6-hydroxydopamine (6-OHDA) into the vicinity of cell bodies of the ventral noradrenergic bundle (VNAB) on weight gain, food intake and brown adipose tissue (BAT) activity (as measured by GDP binding in BAT mitochondria), were examined in rats at two different ages and under two different dietary conditions (chow and chow plus palatable cheese). VNAB lesions enhanced weight gain in the chow plus cheese diet conditions and produced small increases in feeding. These effects were parallelled by reductions in BAT activity in the VNAB group, suggesting a reduced capacity for dietary thermogenesis which may contribute to the significant overweight.

Adipose Tissue, Brown↗