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Biomedical subjects

D J Bowen

Publications and source records attributed to D J Bowen.

At least 19 recordsLinked to original sources
PubMed1992

Taste and food preference changes across the course of pregnancy.

The present study investigates taste and specific food consumption changes across the course of pregnancy. These variables could potentially play a role in excess pregnancy-associated weight gains. Pregnant and postpartum women were asked to consume a series of everyday foods in the laboratory. Consumption and taste perception of each food were measured. In contrast to the self-report literature on cravings and aversions during pregnancy, which emphasizes changes in the first trimester, this study found that women in the second trimester consumed significantly more sweet food, but not salty or non-sweet/non-salty food, as compared with women at any other point in pregnancy. Subjects were restrained eaters, and so possibly refrained from daily consumption of excess sweet foods. This study suggests that psychological variables may interact with behavioral and physiological variables to control food preferences and eating in pregnancy.

Adult↗
PubMed1992

The relationship of HIV-1 viral sequences detected by the polymerase chain reaction in haemophilic patients to clinical and other markers of infection.

A nested primer polymerase chain reaction (PCR) of pol gene sequences of human immunodeficiency virus-1 (HIV-1) was applied to whole blood of 31 haemophiliacs who were, or had been, positive for HIV p24 antibody (HIVAb) by enzyme linked immunosorbent assay (ELISA) and samples from 22 persistently HIVAb negative haemophiliacs who had been at risk of contracting HIV from treatment. The results were compared with those of p24 HIV antigen determination, T4 cell counts beta 2 Microglobulin (beta 2M) levels and clinical evidence of progression of HIV disease. There was no discrepancy between the PCR results and past or present seropositivity for HIVAb. The qualitative PCR was more sensitive than the p24 antigen assay but the presence of the latter was predictive of progression of infection as determined clinically and by falling T4 cell counts and rising levels of beta 2M. The results of the PCR are reassuring for HIVAb negative haemophiliacs at risk from treatment and to HIVAb negative sexual contacts of HIVAb positive persons.

Adult↗
PubMed1991

Evidence for an involvement of eicosanoids in neurokinin3-receptor mediated acetylcholine release from myenteric neurons.

The release of acetylcholine (ACh) from myenteric plexus evoked by 5-hydroxytryptamine (5-HT) and senktide (a selective neurokinin3 (NK3) agonist) was depressed by mepacrine, an inhibitor for phospholipase A2 activity. Release of ACh was stimulated by arachidonic acid; this release was partially depressed by nordihydroguaiaretic acid (NDGA), which inhibits lipoxygenase activity. NDGA failed to modify the ACh secretion elicited by 5-HT. Release of ACh evoked by senktide was significantly inhibited by NDGA, suggesting an involvement of eicosanoids in the release of ACh elicited by specific neurokinin receptors in myenteric neurons.

Acetylcholine↗
PubMed1991

Tryptophan and high-carbohydrate diets as adjuncts to smoking cessation therapy.

Treatments that reduce the immediate effects of smoking withdrawal have potential for helping smokers quit. Serotonin-enhancing substances, such as tryptophan and high-carbohydrate diets, have been used in clinical disorders to relieve negative affect, a classic symptom of cigarette withdrawal. This research project investigated the use of tryptophan (50 mg/kg/day) and high-carbohydrate diets, together with more traditional smoking cessation treatment techniques, to ameliorate the smoking withdrawal syndrome and to improve abstinence rates. Subjects were randomly assigned to receive either tryptophan (n = 16) or placebo (n = 15). Standard smoking cessation treatment was identical for the experimental and control groups and consisted of four 2-hr weekly sessions of multicomponent group therapy. Smoking behavior, symptoms of nicotine withdrawal, and negative affect were assessed during a 2-week withdrawal period. Tryptophan-treated subjects who could not fully abstain were able to smoke fewer daily cigarettes. Reported anxiety and other withdrawal symptoms were lower in the tryptophan group compared with control subjects. These data suggest that serotonin-enhancing substances show promise for use as an adjunct to existing smoking cessation programs.

Adolescent↗
PubMed1991

Descriptions of early triers.

The onset of smoking behavior in adolescents has been described as a process, beginning when children are young. Little empirical evidence is available, however, on the nature and specifics of the onset process in young children. More information is needed about the early stages of smoking onset in order to design interventions for young children and for early triers. The purpose of the present study was to describe several onset-related variables in young girls and boys and to discuss implications for designing prevention interventions that target young children. A total of 1,663 5th-grade students completed a questionnaire assessing smoking behavior, psychosocial characteristics, and perceptions of a "smoker" image. Saliva samples for cotinine analysis were also collected. Students were classified as either never-triers (never tried a cigarette) or early triers (tried one or more cigarettes) on the basis of self-reported smoking. Most students who had tried a cigarette were in the early stages of smoking onset, because approximately 30% had tried one cigarette and less than 10% had tried a second. Triers versus never-triers differed on their reported images of smokers, and several psychosocial characteristics predicted trying a cigarette and intentions to smoke for boys.

Attitude↗
PubMed1991

The triple threat: a discussion of gender, class, and race differences in weight.

Gender, poverty and race, the "triple threat" referred to in the title, are three major risk factors that contribute to the high prevalence of weight-related problems in this country. Current psychological literature on weight management has generally ignored the effects of these variables and their implications for developing interventions for underserved populations which include women, minorities and poor people. The present paper discusses the literature on the effects of gender, race, and class on weight levels and associated psychosocial variables. Conclusions drawn illustrate that weight is a major issue for women, and that race and class also have effects on weight levels which can affect health status. Areas of further exploration and of action are identified to address problems that women face regarding weight.

Attitude to Health↗
PubMed1990

Variations in food preference and consumption across the menstrual cycle.

There is some evidence that food consumption changes across the menstrual cycle. However, archived studies tend to rely on self-report data and do not differentiate among types of food eaten. The present laboratory study was designed to measure women's taste preferences and specific food consumption across the menstrual cycle. Women came into the laboratory, consumed everyday foods, and rated them on taste judgment scales. The foods were weighed before and after the tasting session to determine amount eaten. After the tasting session, subjects completed several questionnaires (e.g., measures of affect, restrained eating, menstrual cycle and menstrual symptoms). Physical measurements (e.g., height, weight) were taken at the end of the session. Sweet food consumption and preference ratings were significantly higher during the premenstrual period. Consumption and ratings of other foods did not differ. There were no differences in levels of mood, obesity, or restrained eating across the menstrual cycle. Low restraint was associated with reporting fewer menstrual symptoms, in general, and slightly better mood. These results support the idea that specific taste preferences change over the menstrual cycle, and that endocrinological factors could be involved in this phenomenon.

Adult↗
PubMed1990

Site-directed mutagenesis of aspartic acid 372 at the ATP binding site of yeast phosphoglycerate kinase: over-expression and characterization of the mutant enzyme.

A new phosphoglycerate kinase over-expression vector, pYE-PGK, has been constructed which greatly facilitates the insertion and removal of mutant enzyme genes by cleavage at newly introduced BamHI sites. This vector has been used to prepare mutant protein in appreciable (100 mg) quantities for use in kinetic, crystallographic and NMR experiments. Aspartate 372 is an invariant amino acid residue in genes known to code for a functionally active PGK. The function of this acidic residue appears to be to help desolvate the magnesium ion complexed with either ADP or ATP when this substrate binds to the enzyme. Both crystallographic and nuclear magnetic resonance experiments show that the replacement of the residue with asparagine has only minimal effects on the overall structure. The substitution of the charged carboxyl group with that of the neutral amide affects the binding of the nucleotide substrate as predicted but not, as might have been expected, the binding of 3-phosphoglycerate. The overall velocity of the enzymic reaction (Vmax) is reduced 10-fold by the substitution of aspartic acid 372 by an asparagine residue (D372N). This reduction in Vmax is considerably less than one would expect from its known position within the structure of the enzyme. This result therefore poses questions about our understanding of charged groups at the active centres of enzymes and of the reason for their apparent conservation.

Adenosine Triphosphate↗
PubMed1990

Family studies in von Willebrand's disease by analysis of restriction fragment length polymorphisms and an intragenic variable number tandem repeat (VNTR) sequence.

We have previously identified a microsatellite variable number tandem repeat region of the nucleotide sequence ATCT within intron 40 of the von Willebrand factor (vWF) gene. By polymerase chain reaction (PCR) amplification of this region, eight major alleles have been demonstrated in the South Wales population, with an overall heterozygosity rate of 75%. Direct sequencing has shown that the alleles correspond to lengths of between six and 14 ATCT repeats. In the present study we describe the use of this variable repeat sequence and previously reported restriction fragment length polymorphisms (RFLP) to study inheritance patterns in families with type I, IIA and severe type III von Willebrand's disease (vWD). The results confirm that analysis of this precisely localized intragenic locus provides a highly informative marker for gene tracking studies in the major forms of vWD.

Base Sequence↗
PubMed1989

Possible explanations for excess weight gains in pregnancy: an animal model.

An animal study was designed to address the reasons for excess pregnancy-associated weight gains. Forty-eight adult female rats were divided into two diet groups: a bland chow group and a chow plus glucose solution group. Half of each group was impregnated. Body weight, consumption of both foods, and water consumption were measured daily before, during, and after pregnancy. During pregnancy and after delivery, animals from each food-by-pregnancy group were killed, and adipose tissue analyses were performed. During pregnancy and during lactation, pregnant rats with two foods consumed more glucose solution and gained more adipose tissue with larger cells than did any other group. Taking both studies together, pregnancy is accompanied by sweet food consumption increases and can lead to adipose tissue gains in subjects not influenced by psychological variables.

Adipose Tissue↗
PubMed1988

Effects of chronic nicotine administration on insulin, glucose, epinephrine, and norepinephrine.

There is an inverse relationship between nicotine administration and body weight. Previous research indicates that this relationship results partially from effects of nicotine on energy intake. The present research includes two animal studies designed to investigate the effects of chronic nicotine administration on biochemical responses that affect energy utilization. The results indicate that chronic nicotine administration is accompanied by significant decreases in circulating insulin levels. Nicotine increases levels of catecholamines, but this effect is short-lived. The effects of nicotine on insulin are consistent with the conclusion that nicotine administration increases energy utilization.

Animals↗
PubMed1986

Effects of nicotine on body weight and food consumption in female rats.

Women often report that they smoke cigarettes to avoid weight gains and that they relapse after abstaining from tobacco because of weight gains. Men also report these concerns but to a lesser extent. This gender difference may reflect sociological and cultural pressures about physical appearance, or it may reflect sex differences in the effects of nicotine. The present research was designed to examine the effects of nicotine administration and cessation of nicotine on body weight, food consumption, and water consumption. Alzet miniosmotic pumps were implanted SC to administer saline or three different concentrations of nicotine to female Sprague-Dawley rats for 17 days. This paradigm has been used in previous studies of nicotine and body weight in male rats. Animals were used as subjects to avoid cultural factors and cognitive concerns about body weight. Nicotine administration decreased normal body weight gains and cessation of nicotine was accompanied by significant increases in body weight compared to controls. In contrast to previous studies of male rats, the nicotine-related changes in body weight were accompanied by changes in bland food and water consumption. These findings indicate that females are more sensitive than males to the effects of nicotine on body weight and feeding during and after drug administration.

Animals↗