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Biomedical subjects

G Bennett

Publications and source records attributed to G Bennett.

At least 55 records · Page 3Linked to original sources
PubMed1996

Stable inheritance of an HLA-"blank" phenotype associated with a structural mutation in the HLA-A*0301 gene.

A serological family study identified an HLA-A "blank" segregating through three generations of apparently healthy individuals. The HLA-A*0301 allele was assigned by DNA genotyping in each of the three individuals. Complete absence of cellular expression of the HLA-A3 antigen was associated with a 6 nucleotide deletion in exon 3 of the A*0301 gene. The in-frame deletion of nucleotides 373-378 results in the absence of residues C101 and D102 from the mature HLA-A heavy chain. Cysteine 101 is involved in the formation of the highly conserved disulfide bridge in the alpha 2 domain of the class I molecule, and deletion of this residue is believed to be highly disruptive to proper folding and function of the class I molecule.

Base Sequence↗
PubMed1996

Smoking policy and cessation in an inner-city hospital.

Hospital policies regarding cigarette smoking can affect the smoking habits of employees, patients, and visitors. Successful smoking policy development and impact have been reported in a number of hospitals. These reports have been from financially secure or university hospitals. This article reports on the policy experience at Interfaith Medical Center, a public hospital serving an economically disadvantaged black inner-city community. Policy implementation and smoking cessation efforts were directed by a broad-based hospital committee. An employee survey demonstrated support for a policy restricting but not banning smoking (89% of nonsmokers, and 80.2% of smokers). Among smoking employees, 87.6% wanted to quit. A policy restricting smoking to designated areas in the cafeteria and coffee shop was enacted. Health fairs and smokeout contests were enthusiastically received and resulted in short-term cessation verified by exhaled carbon monoxide levels. Assemblies where ex-smokers were given "Hall of Fame" certificates, "stop smoking" art contests, and a "stop smoking hotline" generated further cessation activity. The department of medicine, in cooperation with the National Heart, Lung, and Blood Institute's Smoking Education Program, set up a training program for residents on how to help patients quit. Overall, the smoking prevalence, attitudes, and enthusiasm to quit were similar to previous reports in financially secure hospitals. Unfortunately, lack of resources and staff turnover led to dissolution of the program. Institutional stability and a funding source are critical for the long-term success of hospital smoking cessation programs.

Adult↗
PubMed1995

Evolution in HLA-DRB1 and major histocompatibility complex class II haplotypes of Australian aborigines. Definition of a new DRB1 allele and distribution of DRB1 gene frequencies.

The distribution of HLA-DRB1 alleles was studied in Australian aborigines from different parts of Australia. There were significant differences in the frequencies of DRB1*0412, 1409, and 1410 between the Central Desert and Yuendumu populations and the previously reported Cape York and Kimberley aboriginal populations. A new DRB1 allele, DRB1*1414, present at low frequency in the Central Desert population, was identified. DRB1*1414 appears to be closely related to DRB1*1407 and is proposed to have arisen by intragenic recombination. A novel DR-DQ haplotype, DRB1*1402-DRB3*0101-DQA1*0501-DQB1*0402, was also identified. This haplotype may be ancestral to the DRB1*1409-DQB1*0402 haplotype present in these populations. The presence of alleles and haplotypes apparently confined to Australian aboriginal populations and differences in the distribution of these alleles in different populations suggests that evolution has occurred in the class II region in the period since colonization of Australia, an estimated 50,000 years ago.

Amino Acid Sequence↗
PubMed1995

The effects of cardiopulmonary bypass on systemic and coronary levels of von Willebrand factor.

Von Willebrand factor antigen (vWF Ag) is a marker of endothelial injury which has been shown to rise during surgical procedures, including cardiopulmonary bypass (CPB). The aim of this study was to determine whether intermittent aortic cross-clamping during CPB causes the release of vWF Ag from the coronary vascular bed, which would suggest coronary vascular endothelial cell perturbation. Fifteen consecutive patients undergoing CPB with aortic cross-clamping during coronary artery bypass surgery and/or valve replacement by the same surgeon were studied. Paired venous and coronary sinus samples were taken pre- and post-thoracotomy, prior to cross-clamping on CPB, and 1, 5 and 10 minutes after release of the aortic cross-clamp. Plasma vWF Ag (IU/ml) was measured by ELISA. Venous vWF Ag measured prior to skin incision was 0.75 +/- 0.11 IU/ml (mean +/- SEM) and fell to 0.53 +/- 0.07 IU/ml after institution of CPB but prior to aortic cross-clamping (P < 0.01 vs pre-incision sample). Coronary sinus vWF Ag measured prior to aortic cross-clamping was 0.54 +/- 0.06 IU/ml (P = NS vs paired venous sample). At 1, 5 and 10 min after release of the aortic cross-clamp there was a progressive rise in vWF Ag in both venous and coronary sinus samples (1 min: 0.67 +/- 0.05 IU/ml vs 0.75 +/- 0.10 IU/ml, 5 min: 0.73 +/- 0.07 IU/ml vs 0.76 +/- 0.09 IU/ml, 10 min: 0.74 +/- 0.08 IU/ml vs 0.79 +/- 0.09 IU/ml; P = NS venous vs coronary sinus, respectively). Levels of vWF Ag were highest immediately prior to the termination of CPB (venous: 0.95 +/- 0.12 IU/ml; coronary sinus: 0.91 +/- 0.14 IU/ml). We conclude that cardiac surgery using CPB with aortic cross-clamping is associated with a progressive rise in coronary sinus and venous levels of vWF Ag.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

HLA class I variation in Australian aborigines: characterization of allele B*1521.

Traditional methods of serological typing have largely used antisera of Caucasoid origin, which can overlook HLA heterogeneity in non-Caucasoid populations. Therefore, we have used molecular techniques to evaluate potential polymorphism in HLA class I molecules of Aborigines from the central desert and northern coast of Australia. The DNA sequence of common Aboriginal HLA-A and B antigens were compared with serological reaction patterns which suggested new polymorphisms. Although serological data indicated that long and short variants of A34 may exist, regardless of the serological pattern, all individuals carried the A*3401 allele. Therefore, the variation in A34 reaction pattern observed serologically was not attributable to primary sequence variation in the HLA A*3401 allele. Similarly, there was no detectable polymorphism in the sequences of selected HLA-B alleles, even though some of these alleles showed unusual serological reaction patterns. However, a new allele of B15 (B*1521) was detected in two individuals carrying this serotype. The cells from both of these individuals showed ambiguous reaction patterns with monospecific B62 and B75 sera. cDNA sequencing of the HLA B15 gene from these cells revealed a B15 allele that differed from B*1502 by a single nucleotide change. This change occurred at position 272, resulting in a C to G substitution at residue 67 in the consensus B15 cDNA sequence. Hence, the Australian Aborigines as an ethnic group show very little primary sequence polymorphism within the class I loci, consistent with the results obtained from previous serological studies.

Amino Acid Sequence↗
PubMed1995

Positioning post-outpatient cardiac catheterization.

UNLABELLED: The optimal positioning post-outpatient cardiac catheterization is a largely unexplored area of research. Traditionally, patients have been placed supine, with the head of the bed (HOB) flat. This study sought to explore the influence of three different post-procedure positions on the incidence of complications and patient perceptions of satisfaction. Sixty-nine patients were randomized into three groups immediately after hemostasis of the arterial puncture site was achieved. Group 1 patients were placed supine with the HOB flat. Group 2 patients were placed on their sides, with the affected extremity straight. Group 3 patients were placed on their backs, with the HOB at 15-30 degrees. Endpoints included the presence of any complication (bleeding, hematoma formation or expansion, back pain and urinary retention) and patient comfort and satisfaction with the randomized position. Patients were asked prior to discharge to select the position they would have preferred post-procedure. Selection of an alternative position was felt to indicate dissatisfaction with the randomized position. Ten patients in Group 1, and nine patients in Group 2 and Group 3 experienced a complication (X2 = 3.682, df = 1, p = 0.05). Eighty-five percent of Group 1 patients selected an alternative position vs. 24% of those patients in Group 2 and Group 3 (X2 = 27.6, df = 1, p < .001). CONCLUSION: varying patient position post-outpatient cardiac catheterization is at least as safe as the traditional supine position and is more comfortable for patients.

Adult↗
PubMed1994

Passive stiffness of the lumbar torso in flexion, extension, lateral bending, and axial rotation. Effect of belt wearing and breath holding.

This work investigated the passive bending properties of the intact human torso about its three principal axes of flexion: extension, lateral bending, and axial rotation. Additionally, the effects of wearing an abdominal belt and holding the breath (full inhalation) on trunk stiffness was investigated. The torsos of 22 males and 15 females were subjected to bending moments while "floating" in a frictionless jig with isolated torso bending measured with a magnetic device. Belts and breath holding appear to stiffen the torso about the lateral bending and axial rotation axes but not in flexion or extension. Torsos are stiffer in lateral bending and capable of storing greater elastic energy. Regression equations were formulated to define stiffness and energy stored for input to biomechanical models that examine low back function and for bioengineers designing hardware for stabilization and bracing or investigation of traumatic events such as automobile collision.

Abdomen↗
PubMed1994

Mechanistic studies of uridine diphosphate glucuronosyltransferase.

Bisubstrate reaction kinetics and product inhibition studies were used to characterize the kinetic mechanism of a partially purified uridine diphosphate glucuronosyltransferase (UDPGT). These studies indicate that the reaction most likely occurs via a random order sequential mechanism. The effect of electron withdrawing and donating groups on the rate of reaction was also determined. It was found that electron donating groups increased the rate of glucuronide conjugation. This result is consistent with nucleophilic attack of the C-1 carbon of the UDP-glucuronic acid (UDPGA) by an SN2 mechanism. This is the first direct evidence for a SN2 mechanism in UDPGT catalysis.

Animals↗
PubMed1994

Developing an effective infection control program for home care.

Home care agencies can develop comprehensive, effective infection control and prevention programs by including six critical elements: surveillance for infections, infection control education, consultation, epidemiological investigation, quality improvement activities, and policy and procedure development.

Centers for Disease Control and Prevention, U.S.↗