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Biomedical subjects

J Peacock

Publications and source records attributed to J Peacock.

At least 19 recordsLinked to original sources
PubMed1999

How to make nutrition education more meaningful through facilitated group discussions.

Facilitated group discussions provide an alternative method to lecture and one-on-one approaches for conducting educational interventions at clinic sites. They are an interactive form of education wherein learners generate the specific topics to be addressed and share their knowledge and experience with other group members through discussion. In brief, the educator becomes a facilitator who, rather than lecturing, encourages clients to discuss freely among themselves their own approach to the nutrition problems posed during the session. As a facilitator, the nutritionist strives to create a comfortable atmosphere for discussion, encourages participation, and interjects only to correct misinformation and manage group dynamics. Facilitated group discussions allow nutrition practitioners to deliver meaningful nutrition education in a manner that helps empower their clients to improve their dietary habits; at the same time such discussions meet the increased public administrative demands for efficiency. Possible benefits to clients include more confidence, better communication skills, improved thinking skills, and increased motivation and commitment to improving nutrition behavior. We recommend that nutrition educators try facilitated group discussions in their clinics.

Group Processes↗
PubMed1999

Serological discrimination of dogs infected with gastric Helicobacter spp. and uninfected dogs.

Characterization of the humoral immune responses of people to Helicobacter pylori infection has facilitated the investigation of the host response to bacterial virulence factors and the development of sensitive and specific diagnostic tests. Dogs are commonly infected with gastric Helicobacter spp., but the presence of multiple Helicobacter spp. and possible coinfection in individual dogs have complicated serological evaluation. Evaluation of the antigenic homology of Helicobacter spp. revealed that the major protein bands of Helicobacter felis and Helicobacter bizzozeronii, two Helicobacter spp. that infect dogs, were very similar to UreA (29 to 31 kDa), UreB (63 to 66 kDa), and HSP (58 to 60 kDa) of H. pylori, and sera from infected and uninfected dogs bound in a similar way to each antigen. Immunoblotting and an enzyme-linked immunosorbent assay (ELISA) with H. felis ATCC 49179 antigen were performed with 101 serum samples (from 78 infected dogs and 23 uninfected dogs). Samples from uninfected dogs (median = 8) had fewer bands on immunoblotting than samples from infected dogs (median = 16) (P < 0.05). Combinations of the presence of any two of the low-molecular-mass bands (19, 25, 30, 32, and 37 kDa) or the high-molecular-mass bands (86 and 94 kDa) were found almost solely in samples from infected dogs (P < 0.0001). Kinetic ELISA results were significantly higher for samples from infected dogs (median = 0. 0802 optical density unit [OD]/min) than for samples from uninfected dogs (median = 0.01428 OD/min). The combination of ELISA and immunoblotting results gave a specificity of 95.6% and a sensitivity of 79.8%. No correlation between ELISA results, colonization density, degree of inflammation, and presence of lymphoid follicles was observed. The results indicate substantial antigenic homology between H. felis, H. pylori, and H. bizzozeronii. The combination of ELISA and immunoblotting was a highly specific and moderately sensitive indicator of infection. The degree of seropositivity assessed by ELISA was not related to bacterial colonization density, the degree of gastric inflammation, or the presence of lymphoid follicles.

Animals↗
PubMed1999

The effect of different bypass flow rates and low-dose dopamine on gut mucosal perfusion and outcome in cardiac surgical patients.

The aim of this double-blind, randomized, placebo-controlled trial was to investigate the effects of different cardiopulmonary bypass flow rates and low-dose dopamine on gastric mucosal pH (pHi) and outcome. We hypothesized that by minimizing gut mucosal hypoperfusion during and after cardiac surgery endotoxin translocation may be prevented, resulting in an improved clinical outcome. Four groups of 25 patients each receiving high or low flows during bypass and low-dose dopamine or saline for 24 hours after induction of anaesthesia were studied. The pHi was measured at six time intervals over 24 hours. The combination of low-dose dopamine and a low bypass flow rate was associated with a significantly greater frequency and severity of low pHi. This group also demonstrated a significantly lower vascular resistance on admission to the intensive care unit. There may be an association between low pHi and low vascular resistance.

Cardiopulmonary Bypass↗
PubMed1998

Radioresistant MTp53-expressing rat embryo cell transformants exhibit increased DNA-dsb rejoining during exposure to ionizing radiation.

Recent data suggest that aberrant function of the wild type p53 protein (WTp53) may alter cellular survival following DNA damage through cellular pathways involving apoptosis and cell-cycle checkpoints, but little is known concerning it's possible role in DNA repair. In the present study, the ionizing radiation sensitivity was determined for a series of rat embryo fibroblast (REF) cell lines transfected with an activated form of the H-ras oncogene alone, or in combination with a variety of missense-mutant p53 (MTp53) alleles. Transformed REF clones which expressed exogenous MTp53 and p21ras proteins (CLASS II clones) were generally radioresistant in culture as determined by higher values for the surviving fraction after 2 Gy (SF2 value) and the radiation dose required to reduce survival to a fraction of 0.1 (D10 value), compared either to transformed REF clones expressing p21ras protein alone (CLASS I clones), or to non-transfected REF control cell lines expressing baseline endogenous levels of p21ras and WTp53 protein. The increased radioresistance observed in the CLASS II clones (following both HDR- and LDR-irradiation), was significantly correlated with increased expression of MTp53 protein, and a decreased radiation-induced G1 arrest response. The variability observed in clonogenic radiosensitivity among REF clones was not explained by differential radiation-induced apoptosis. Using the Comet assay performed after continuous low dose-rate (LDR)-irradiation, MTp53-expressing REF clones were also found to be more proficient at the rejoining of DNA double-strand breaks (DNA-dsb), compared to WTp53-expressing REF clones. These results suggest that an enhanced DNA and cellular repair capacity may, in part, explain the increased radiation survival observed in some MTp53-expressing transformed fibroblasts and tumours.

Animals↗
PubMed1998

Are women who have abortions different from those who do not? A secondary analysis of the 1990 national survey of sexual attitudes and lifestyles.

Studies of women undergoing termination of a pregnancy are often used to make recommendations about family planning and health education policy. However, it is not clear how similar the women in these studies are to the general population of women of childbearing age. Our secondary analysis of the National Sexual Attitudes and Lifestyles Survey allowed us to test the hypothesis that women who have undergone an abortion are the same as those who have not (in terms of socio-demographic characteristics, lifestyles, and attitudes). Our findings show significant differences between these two groups of women, particularly regarding ethnicity, marital status, number of natural children, lifetime number of sexual partners, and attitudes to abortion. We conclude that family planning/reproductive health services and health education policies need to take these differences into account and that further research is required to explain why these differences arise.

Abortion, Legal↗
PubMed1998

Determination of epidermal transpiration in four cultivars of Nicotiana tabacum L. using epidermal strips in a quasi-steady state system.

A quasi-steady state method is presented for quantifying epidermal transpiration of epidermal strips where simple relations between transmembrane fluxes and parameters of diffusibility of penetrating compounds hold. Contrary to most permeability studies, we did not use astomatous, enzymatically isolated, or dried cuticular membranes, because these procedures are largely responsible for the problems cited in the literature. Instead, we used freshly harvested stomatous epidermal strips, thus avoiding the sorption of lipids by the cuticular membranes during enzymatic isolation. Our approach allowed estimation of amounts and composition of intracuticular soluble lipids. Diffusion coefficients (D-values) were calculated with smaller associated standard deviations and an order of magnitude lower than previously reported; the fresh material sorption of the diffusing compound by the membrane and hydration of the cuticular pores was greatly reduced. In the present study the hold-up time (te) ranged from 66.2+/-0.3 to 110.3+/-0.9 sec. Furthermore, 0.1 microm thick membranes were used, contrary to previous studies of water permeability that used cuticles more than 2 microm thick. Because a small but constant flow of penetrant could be detected during the first half of the steady flow to te, small holes probably did not influence the reported permeability. Permeability coefficients (Pd) in the order of 0.65 x 10(-9) ms(-1) were calculated. Pd values in the order of 5.68 x 10(-3) ms(-1) were calculated when incomplete stomatal closure occurred, while when areas of mass flow were detected, Pd values in the order of 1.26 x 10(-2) ms(-1) were calculated. The degree of contamination of the epidermal strips by cellular debris was quantified and expressed as the total chlorphyll content per exposed surface area of the epidermal strip, and an average of 8.7% contamination was observed compared to the total leaf chlorophyll content. Leakage from the system was calculated to be approximately 0.18 x 10(-10) ms(-1), which represents an average 2.7% experimental variability. These results are discussed in terms of the limitations associated with using composite membranes that are stomatous and have trichomes, for possible application in drought tolerance selection.

Lipids↗
PubMed1997

Mutator phenotype in Msh2-deficient murine embryonic fibroblasts.

Embryonic fibroblast cell lines were established from mice deficient, heterozygous, or proficient for Msh2, one of the three known DNA mismatch repair genes involved in hereditary nonpolyposis colon cancer (HNPCC). Cell lines were established by transfection of primary mouse embryo fibroblasts with E7 and Ras oncogenes or mutant p53. Spontaneously immortalized cells derived from the primary cultures were also studied. To determine whether these cells developed a mutator phenotype similar to that found in colon cancer cells deficient in mismatch repair, we measured mutation rates, microsatellite instability, and sensitivities to a range of DNA-damaging agents. The mutator phenotype detected in the E7 and Ras or mutant p53-immortalized Msh2-/- mouse cells was similar to that found in human mismatch repair-deficient colorectal carcinoma cell lines. Mutation rates to ouabain resistance were increased 8-12-fold relative to lines from Msh2+/+ mice, and microsatellite instability was detectable in 12-18% of subclones derived from the Msh2-/- line but was undetectable in subclones developed from the Msh2+/+ line. Furthermore, E7 and Ras or spontaneously immortalized Msh2-/- cells were significantly more resistant to the cytotoxic effects of 6-thioguanine relative to Msh2+/+ cells. In contrast, these lines showed various responses to UV light and cis-platinum, suggesting that mismatch repair deficiency was not the sole determinant for sensitivity to these DNA-damaging agents. Particular attention was paid to the properties of cells heterozygous for the Msh2 mutant gene, which would mimic the situation of an HNPCC carrier. However, our studies failed to reveal any properties of these cells that might provide a growth advantage or predispose them for the acquisition of further mutations. This observation is consistent with the model that inactivation of the wild-type Msh2 allele is a critical step for tumorigenesis in HNPCC patients.

Animals↗
PubMed1997

An in vitro study on the effect of branch points on the stability of coronary artery flow.

Empirical correlations for the onset of turbulence in pulsatile flow through a straight tube and a 45 degrees T-bifurcation are presented. We pumped three different test fluids of kinematic viscosity 0.008-0.035 cm2 s-1 through four straight tubes 0.4-3.0 cm in diameter and three 45 degree T-bifurcations 0.45-2.2 cm in diameter. A Scotch yoke mechanism provided an oscillatory sine wave flow component of known stroke volume and frequency. To determine transition to turbulence, we adjusted the mean flow independently until we detected signal instabilities from hot film or electrochemical wall shear stress probes. The critical peak Reynolds number was found to correlate with two independent dimensionless groups: the Womersley parameter and the Strouhal number. We derived power low functions of these groups to provide an accurate and convenient method of predicting transition in both straight and bifurcating tubes. When compared to pulsatile flow through the straight tube, the presence of flow separation within the 45 degrees T-bifurcation induced flow instabilities at lower values of the peak Reynolds number. The correlation for the 45 degrees T-bifurcation is also a suitable model for predicting transition at coronary branch points, which we previously studied in an in vitro pulse duplicator. Flow instabilities at coronary branch points may play an important role in atherogenesis.

Arteriosclerosis↗
PubMed1997

Gallstone removal with a modified cholecystoscope: an alternative to cholecystectomy in the high-risk patient.

BACKGROUND: Symptomatic gallstones in patients who are at high risk from or who wish to avoid anesthesia may be difficult to treat, especially if the gallstones are unsuitable for oral dissolution or lithotripsy. We describe our experience with a minimally invasive surgical method of gallstone extraction under thoracic epidural or intercostal anesthesia. STUDY DESIGN: Eight-one patients who were either at high risk from or did not wish to undergo general anesthesia or those who wished to conserve their gallbladder underwent percutaneous cholecystolithotomy with a modified cholecystoscope. Of these patients, 63 (78 percent) were in American Society of Anesthesiology grades III and IV and 28 (35 percent) had thick-walled, diseased gallbladders. RESULTS: Gallstones were completely cleared in 66 (81 percent) patients and complete symptom relief was obtained in more than 95 percent of these patients. There were no deaths or serious complications. CONCLUSIONS: Percutaneous cholecystolithotomy under regional anesthesia is an effective means of gallstone treatment in selected high-risk patients.

Adult↗
PubMed1997

Detection of serum antibodies to Helicobacter pylori by an immunochromatographic method.

OBJECTIVES: FlexsureHP is a bi-directional immunochromatographic device for detection of IgG antibodies to Helicobacter pylori in human serum. This test, requiring only three steps and a 4-min incubation, can be used as an office-based diagnostic test. The goal of this study was to compare the sensitivity and specificity of the FlexsureHP, when performed by a clinician, with the established ELISA in the evaluation of clinical samples in an office setting. RESULTS: The sensitivity and specificity of the FlexsureHP, compared with the biopsy, is 92.4% and 83.0%, respectively, with a positive predictive value of 88.4%. This was not significantly different from the results obtained when the ELISA was compared with biopsy data. CONCLUSION: The immunochromatographic device, FlexsureHP, is a rapid, highly sensitive, and moderately specific office-based diagnostic test for H. pylori infection.

Adult↗
PubMed1996

Randomised, prospective, single-blind comparison of laparoscopic versus small-incision cholecystectomy.

BACKGROUND: We report a prospective randomised comparison between laparoscopic and small-incision cholecystectomy in 200 patients which was designed to eliminate bias for or against either technique. METHODS: Patients were randomised in the operating theatre and anaesthetic technique and pain-control methods were standardised. Four experienced surgeons did both types of procedure. Identical wound dressings were applied in both groups so that carers could be kept blind to the type of operation. FINDINGS: There was no significant difference between the groups for age, sex, body mass index, and American Society of Anaesthesiologists grade. Laparoscopic cholecystectomy took significantly longer than small-incision cholecystectomy (median 65 [range 27-140] min vs 40 [18-142] min, p<0.001). The operating time included operative cholangiography which was attempted in all patients. We found no significant difference between the groups for hospital stay (postoperative nights in hospital, median 3-0 [1-17] nights for laparoscopic vs 3-0 [1-14] nights for small-incision, p=0.74), time back to work for employed persons (median 5-0 weeks vs 4.0 weeks; p=0.39), and time to full activity (median 3-0 weeks vs 3.0 weeks; p=0.15). INTERPRETATION: Laparoscopic cholecystectomy takes longer to do than small-incision cholecystectomy and does not have any significant advantages in terms of hospital stay or postoperative recovery.

Analgesia, Patient-Controlled↗
PubMed1996

P53-mediated radioresistance does not correlate with metastatic potential in tumorigenic rat embryo cell lines following oncogene transfection.

PURPOSE: Changes in wild-type p53 protein function occur in the majority of human tumors, and may alter genomic stability and the cellular response to ionizing radiation. Whether oncoproteins can render tumor cells both radioresistant and metastatic, may have implications for clinical strategies designed to improve local tumor control. In the studies reported here, we tested the hypothesis that acquired radioresistance correlates with metastatic potential within a large panel of transformed rat embryo cell (REF) lines following transfection with activated H-ras, mutant p53, and HPV16-E7 alleles. METHODS AND MATERIALS: Rat embryo cells (REF cells) were transfected using the calcium-phosphate technique with an activated H-ras gene alone, or in combination with human papillomavirus HPV16-E7 and/or human or murine mutant p53 sequences. Other rat embryo cell clones expressing transfected HPV-E7 and activated ras sequences subsequently acquired endogenous p53 gene mutations during culture in vitro. The relative expression of p21ras and p53 protein for each REF transformant was determined by Western blot analysis following transfection. REF clones were phenotypically characterized at early passage (i.e., passages 5-7) and late passage (i.e., passages 10-20) for their: (a) relative tumor growth rate, and (b) their ability to undergo spontaneous metastasis following intramuscular injection into the hind legs of SCID mice. In vivo phenotypic end points were then compared to previously measured parameters of in vitro radiosensitivity for each cell line. Additionally, the expression of the cellular protease, plasminogen activator, was determined for a number of metastatic and nonmetastatic cell lines. RESULTS: We found no evidence that selected oncogene-transfected REF transformants that were radioresistant in culture had a greater spontaneous metastatic potential than nonradioresistant REF transformants. Neither the level of expression of the p21ras protein nor that of the p53 protein was correlated with the spontaneous metastatic phenotype when tested at early passage. The metastatic phenotype appeared to be independent of p53 genotype. The majority of metastatic REF clones tested (7 out of 9 clones) expressed plasminogen activator following oncogene transfection, in contrast to nonmetastatic REF transformed cell lines. CONCLUSIONS: Our results suggest that (a) intrinsic radioresistance does not correlate with spontaneous metastatic potential in oncogene-expressing REF transformant cell lines, and (b), novel clinical strategies designed to overcome oncogene-mediated radioresistance could potentially impact on overall survival, as gains in local tumor control may not be offset by a greater risk of distant metastasis.

Animals↗
PubMed1996

Methicillin-resistant Staphylococcus aureus: investigation of a hospital outbreak using a case-control study.

A retrospective case-control study of 50 MRSA-positive patients was carried out during an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) at an acute general hospital in London. Controls were randomly selected from MRSA-negative patients admitted during the outbreak period. Risk factors investigated included length of admission prior to screening, number of ward changes, main diagnosis, extent of staff contact, pressure sores, surgical and other invasive procedures and antibiotic treatment. Outcome variables examined were rates of infection (versus colonization) with MRSA and mortality. Patients with MRSA were in hospital longer before microbiological specimens were taken and moved wards more often than controls. In a logistic regression analysis, length of stay in hospital, pressure sores, physiotherapy and surgical procedures were associated with a significantly increased risk of acquiring MRSA. Odds ratios (and 95% confidence intervals) for having acquired MRSA were: 8.3 (1.02-71.43) if a patient had pressure sores; 3.7 (1.10-12.5) if they received physiotherapy; and 3.2 (1.82-10.0) if they underwent surgical procedures. The rate of clinical infection amongst patients with this strain of MRSA was 26% and included life-threatening infections such as septicaemia, underlining the potential virulence of MRSA. Surgery and physiotherapy may have been markers of debility. Physiotherapy was probably a marker of increased rates of contact with all hospital staff, and high standards of hand hygiene should be promoted amongst all staff as the most important factor in controlling an outbreak of MRSA. Good bed management is essential for hospital infection control.

Aged↗
PubMed1996

Acute renal failure in cardiac surgical patients, potentiated by gentamicin and calcium.

A retrospective study in coronary artery bypass graft patients was undertaken to assess the effect of gentamicin and a bypass prime with a high calcium on the incidence of renal failure. Patients who received both Haemaccel (polygeline, Hoechst Marion Roussel) (calcium concentration 6.25 mmol/l) in the bypass prime and gentamicin perioperatively had a higher incidence of renal failure compared with those who received only Haemaccel (P = 0.005), only gentamicin (P = 0.002) or neither (P = 0.0001). We suggest that the combination be avoided in this group of patients.

Acute Kidney Injury↗
PubMed1996

Comparison of rapid serological tests (FlexSure HP and QuickVue) with conventional ELISA for detection of Helicobacter pylori infection.

BACKGROUND: There is a need for accurate and rapid tests for Helicobacter pylori infection especially since the recent National Institutes of Health Consensus Development Conference on H. pylori in peptic ulcer disease charged the medical community with treating H. pylori infection in all patients with H. pylori and ulcer disease. METHODS: We prospectively compared a simple, rapid serological test (FlexSure HP, SmithKline Diagnostics) for the detection of serum IgG antibodies against H. pylori with another rapid test (QuickVue, Quidel) and two enzyme immunoassays (HM-CAP, Enteric Products, and PyloriStat, BioWhittaker). Serum samples from 551 individuals including both symptomatic patients (196) and asymptomatic volunteers (355) were tested for the presence of IgG antibodies against H. pylori. The presence or absence of active H. pylori infections was determined using the [13C]-urea breath test. RESULTS: All of the serological tests performed well. FlexSure HP had calculated sensitivity, specificity, and accuracy of 94.4, 87.6, and 91.1%, respectively, relative to the urea breath test. In 49 of the 551 samples, the urea breath test and FlexSure HP did not agree. Those samples were tested with HM-CAP immunoassay to confirm presence or absence of IgG antibodies against H. pylori. After the resolution of the discordant results, the sensitivity, specificity, and accuracy of FlexSure HP were 96.0, 95.1, and 95.6%, respectively, and were comparable to HM-CAP and PyloriStat. FlexSure HP was compared with histology or culture in 75 cases, and the accuracy was 100%. FlexSure HP and QuickVue were compared using 200 serum samples. FlexSure HP was more specific (88.7 vs 79.4%) and accurate (91 vs 84%) than QuickVue (p < 0.05 for both), relative to the urea breath test with discordant samples unresolved. FlexSure HP was also simpler to use, easier to interpret, and faster than QuickVue. FlexSure HP required no sample dilution, one reagent, four steps, and 5 min to complete. CONCLUSION: FlexSure HP is an excellent option for in-office tests for the physician who desires immediate results or for small laboratories that do not have the volume of H. pylori testing to justify ELISA test formats.

Adolescent↗
PubMed1995

Flow instabilities induced by coronary artery stents: assessment with an in vitro pulse duplicator.

An in vitro pulse duplicator system was used to investigate whether coronary artery stents induce downstream flow instabilities. Hot film or electrochemical probes were used to measure wall shear stress before and after deployment of both single and multiple (overlapping) stents in normal and diseased coronary geometries. Left main coronary diameters ranged from 4 to 5 mm, whereas left anterior descending (LAD) and left circumflex (LCX) diameters ranged from 2 to 4 mm. Under resting conditions, all coronary flow waveforms remained laminar, even after stent placement. However, disturbances were found downstream from a stent placed in the proximal LAD under mild exercise conditions. These disturbances were found 5 mm distal to the stent, in both the LAD and the proximal LCX. Turbulence intensities of order 5% were induced by a single slotted stent in a normal LAD geometry. In cases of distal disease, the turbulence intensity was 9% with one stent and 11% with tandem stents. In cases of proximal disease, these values were 19 and 25%, respectively. The shear stress from these disturbances (20-200 dynes cm-2) is sufficient to delay re-endothelialization and promote restenosis. Therefore, the disturbances could contribute to the increased incidence of restenosis reported with multiple stents, and with stents used in cases of diffuse coronary disease.

Aorta↗