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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
PubMed1995

School policy in COMMIT: a promising strategy to reduce smoking by youth.

Organizational smoking policy has been identified as a potentially effective way to influence health behavior, particularly in worksites. Examining the elements of existing school smoking policies for both students and employees can provide insight into the potential effectiveness of these policies in changing young people's smoking behavior. This paper examines selected components of existing school smoking policies in a national sample of schools at all levels of education as part of the Community Intervention Trial for Smoking Cessation. Schools were questioned about their school smoking policies, related resources, and compliance. The data show much variation in the elements of school tobacco use policy to change smoking behavior. Existing policies in schools differ among grade levels, thus providing different messages about the appropriateness of smoking. Policies differ for students and adults, providing another opportunity for confusion about the messages that policy can deliver. In general, resources available to support existing policies are lacking. Many schools offer classes on knowledge of negative health effects of smoking but do not teach the psychosocial skills necessary to resist tobacco use. In its present forms, school policy has great potential for an effective tool for health promotion, but considerable reform is needed to overcome current barriers.

Adolescent↗
PubMed1995

Allelic associations and homozygosity at loci from HLA-B to D6S299 in genetic haemochromatosis.

Haemochromatosis (GH) is an autosomal recessive disorder in which increased iron absorption causes iron overload. The gene (HFE) is closely linked to HLA-A on chromosome 6 (6p21.3) but has not yet been identified. We have examined eight polymorphic loci, HLA-B (most centromeric), I82, D6S265, HLA-A, D6S128, HLA-F, D6S105, and D6S299 (most telomeric) in 37 unrelated patients and 60 control subjects. There are also significant positive associations between GH and alleles at all loci except D6S299. Analysis of 48 GH chromosomes in which haplotypes could be established showed that the most common haplotype was I82-2:D6S265-1:HLA-A3:D6S128-2:HLA-F1:D6S105-8. This was present in 28 of 48 chromosomes. In 14 the haplotype included HLA-B7 but only in seven did this extend beyond the telomere to D6S299-2 (the most common allele on GH chromosomes at this locus). In 36 out of 48 chromosomes the two locus haplotype, F1:D6S105-8 was present. Since haemochromatosis appears to originate from a founder mutation we have examined linkage disequilibrium between these various loci and GH using calculations of pexcess. The maximum value (0.72, 95% CI 0.55-0.85) is given by D6S105-8 but is not significantly different from values for HLA-A3 and HLA-F1 (0.50, 95% CI 0.34-0.61 and 0.49, 0.25-0.66 respectively). However, both HLA-A and D6S105 give a value for pexcess which is significantly higher than that for the most centromeric marker, HLA-B (0.17, 95% CI 0.02-0.30). We have counted the number of patients who are homozygous for the common allele at each locus. At D6S105, 22 patients are homozygous for allele 8, with 18 homozygous for HLA-F1 and 10 homozygous for A3. The pattern of cumulative homozygosity suggests a gene location closer to D6S105 than HLA-A. We have also analysed our data for divergence from the apparent founder haplotype (A3:F1:105-8) and have calculated the theoretical frequencies of crossovers between loci. These data suggest a location telomeric to D6S105. A more precise localisation of the gene may be possible with the identification of new markers around D6S105.

Adolescent↗
PubMed1994

Effects of dietary fat feedback on behavioral and psychological variables.

This paper reports on the immediate and delayed reactions to dietary fat consumption feedback. Subjects in our study received (1) personalized dietary fat feedback and (2) information about how to alter their fat consumption. Fat consumption was measured using a brief fat assessment instrument. Subjects were categorized into three risk groups: at or below, above, and significantly above the recommended level. Emotional, cognitive, and behavioral reactions were measured immediately after receiving feedback and at 1 month postfeedback. Subjects who received high fat feedback showed greater negative emotional distress in response to the feedback and stated that they knew less about high-fat foods than subjects receiving lower feedback. By the 1-month follow-up, subjects in the highest feedback condition were least likely to report intentions to lower their dietary fat. Interventions designed to alter dietary fat consumption should take into account the emotional and cognitive consequences of risk factor feedback.

Adolescent↗
PubMed1994

Pretreatment with alfentanil reduces pain caused by propofol.

We have compared two groups (n = 22) of unpremedicated patients to determine if the pain caused by injection of propofol could be modified by alfentanil. In group I, alfentanil 1 mg was given as a bolus i.v. injection 15 s before administration of propofol i.v., while group II received saline. Propofol was given in 20-mg increments every 4 s. All injections were given through the same i.v. cannula on the dorsum of one hand. We found that alfentanil pretreatment reduced pain on injection of propofol (P = 0.001).

Adolescent↗
PubMed1994

Alleles at D6S265 and D6S105 define a haemochromatosis-specific genotype.

Hereditary haemochromatosis is an HLA-linked, recessive disorder with HLA-A3 a strong marker for the gene. We have identified molecular markers for two serologically indistinguishable subtypes of HLA-A3 and examined these in 42 patients with haemochromatosis. The common HLA-A3 subtype HLA-A*0301 (highly correlated with allele 1 of D6S265) was a slightly better marker for haemochromatosis (RR = 10.1, Chi2 = 30) than the serologically recognized A3 antigen (RR = 9.1; Chi2 = 27.3). Allele 8 of the more telomeric locus D6S105 was also strongly associated with haemochromatosis (RR = 13.0; Chi2 = 21.1) but alleles at this locus were not in strong linkage disequilibrium with HLA-A alleles in the control subjects. The co-occurrence of D6S265-1 and D6S105-8 alleles yielded a higher risk (RR = 16.9; Chi2 = 44). Homozygosity for the haplotype including these markers was specific for haemochromatosis, i.e. did not occur in 376 healthy subjects but was observed in 21.4% of patients. These results refine the HLA-A3 association with haemochromatosis, suggest that the haemochromatosis gene is located on the telomeric side of HLA-A and define a possible haplotype in which the first mutation may have occurred.

Adolescent↗
PubMed1994

Factor IX gene haplotypes in Brazilian blacks and characterization of unusual DdeI alleles.

Analysis of factor IX gene polymorphisms is considered the best approach for prenatal diagnosis and carrier detection of haemophilia B when the identification of the gene mutation is not possible. Studies involving factor IX gene polymorphisms in Black populations are scarce and essentially restricted to the North-American Black population whose composition is substantially different from that of the Brazilian and presumably other Black populations of South America. In this paper we report the analysis of eight factor IX gene polymorphisms in Brazilian Blacks: 5' BamHI, DdeI, intron 2 BamHI, XmnI, TaqI, TaqI, MspI, MnlI and HhaI. Characterization of the VNTR-like DdeI polymorphism revealed six different alleles: B, AB, A2B, A2B2, A3B and A5B, the last being described here for the first time. The 5' BamHI, DdeI, MspI and HhaI polymorphisms showed the highest heterozygosities (0.40-0.50) and are in linkage equilibrium with one another. 19 complete haplotypes could be identified in this population. Based on the results we propose a systematic strategy for carrier detection and prenatal diagnosis of haemophilia B in this population. The combined analysis of four polymorphisms (5' BamHI, HhaI, MspI and DdeI) provided an informative genetic marker in 85% of the females. The use of all eight polymorphisms allows information in 95% of females. Additionally, differences in gene frequencies and haplotype distribution suggest dissimilarities in factor IX gene polymorphisms between the Brazilian and the North-American Black populations.

Alleles↗
PubMed1993

Female twins with severe Christmas disease (hemophilia B).

Hemophilia B is an X-linked bleeding disorder. We report on female twins, who were conspicious in prolonged bleeding after venipuncture as well as hematomas after intramuscular injections even in the first months of their life. Their father suffering from a severe hemophilia B deceased in 1992. Their mother, half-brother and grandmother from their father's side had no signs of bleeding disorders. Clotting analysis performed in both twins revealed a markedly prolonged partial thromboplastin time (> 100 s). The factor IX levels were below 2%. In order to detect mutations, a general screen using the polymerase chain reaction (PCR) followed by single strand conformation polymorphism (SSCP) analysis of the PCR products have been performed. PCR products have been cut into smaller fragments using restriction endonucleases (RE) for an in-depth SSCP screen. A general screen for gross abnormalities in the factor IX gene including deletions, insertions and rearrangements was performed by Southern blot analysis of RE-digests of genomic DNA using the factor IX cDNA as a hybridization probe. Furthermore, we screened for mutations in the CG dinucleotides comprising part of RE-recognition sequences (exon 1, 2, 3, 4, 5, and 8). By all methods applied herein, no mutations have been detected in these twins. On the basis of our results the hemophilia B of these twins might be explained by extreme non-random lyonization.

Child, Preschool↗
PubMed1993

Factor XIII ABristol 1: detection of a nonsense mutation (Arg171-->stop codon) in factor XIII A subunit deficiency.

Molecular analysis has been performed on a patient with coagulation factor XIII A subunit deficiency. A previously published genomic sequence indicates that exon 4 of the factor XIII A subunit gene contains two TaqI restriction sites within which arginine (CGA)-->stop (TGA) nonsense mutations are possible. Oligonucleotide primers were therefore used to amplify exon 4 by the polymerase chain reaction. TaqI digestion of the 326 base pair (bp) product derived from normal genomic DNA yielded expected fragments of 244, 73 and 9 bp in size. In the case of the patient, however, an additional fragment of 253 bp was present. Direct sequence analysis showed that the 5' TaqI site had been lost from one allele by a C-->T transition at nucleotide 598. Family studies demonstrated the mutation in the patient's father but no other first-degree relatives. This is the third independent mutation described in the factor XIII A subunit gene and the first to be identified in a patient compound heterozygous for the disorder.

Adult↗
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↗