The accuracy of general practitioner records of smoking and alcohol use: comparison with patient questionnaires

BACKGROUND

General practitioner (GP) records are increasingly being used as sources of information on potential confounders such as smoking use and alcohol intake in epidemiological studies. The aim of this study was to assess the accuracy of GP records on smoking use and alcohol intake compared with data from patient questionnaires.

METHODS

Patients registered with 42 practices in Oxfordshire that agreed to take part in a post-marketing surveillance study of omeprazole were sent a postal questionnaire that included questions about alcohol and tobacco use. Two years later, data on these aspects of lifestyle were abstracted from the GP records.

RESULTS

A total of 892 patients agreed to take part in the study; 804 (90 per cent) completed the postal questionnaire, and the records of 856 (96 per cent) were reviewed. Information on smoking and alcohol use was present in 74 per cent and 63 per cent of GP records, respectively. Agreement between the two data sources was moderate for both smoking (kappa = 0.50) and alcohol use (kappa = 0.52). With regard to smoking, the main discrepancy between the two data sources was that 46 per cent (94/206) of patients who reported themselves as exsmokers were recorded as being never smokers in the GP record. With regard to alcohol, there were no systematic differences between the two data sources.

CONCLUSION

Data from GP records on smoking status and alcohol use are incomplete and subject to some misclassification. This is a source of potential failed adjustment for confounding, which should be considered in epidemiological studies that make use of these records.

Detection of TCR-gamma gene rearrangements in early mycosis fungoides by non-radioactive PCR-SSCP

Early mycosis fungoides (MF) can mimic numerous benign inflammatory dermatoses on routine histological examination. In this study, a recently developed non-radioactive polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) technique was used to assess T-cell clonality in paraffin-embedded skin biopsies clinically and pathologically suspicious for early MF. Non-radioactive PCR-SSCP is a simple, sensitive, reproducible and rapid procedure requiring minimal instrumentation. DNA was extracted from 22 skin biopsies of 20 patients with suspected patch stage MF and 15 skin biopsies of inflammatory dermatoses. V gamma1-8, V gamma9, V gamma10, V gamma11 and J gamma1/J gamma2 consensus primers were used for T-cell receptor (TCR)-gamma gene rearrangement amplification. PCR products were analyzed by non-radioactive SSCP. Clonal TCR-gamma gene rearrangements were detected in 17 of 22 (77%) suspected MF specimens. Clonal SSCP banding patterns were different among individual patients. In addition, identical banded patterns were demonstrated in serial skin biopsies from the same patient. No dominant T-cell clones were found in the inflammatory dermatoses studied. Therefore, non-radioactive PCR-SSCP is a useful molecular diagnostic tool for assessment of T-cell clonality in paraffin-embedded specimens suspicious for early MF. The SSCP imprint of PCR products is specific for each TCR-gamma gene rearrangement, and may be used to evaluate concurrent/recurrent disease in individual patients.

Systematic review of the epidemiological evidence on Helicobacter pylori infection and nonulcer or uninvestigated dyspepsia

BACKGROUND

Previous studies have yielded conflicting results and substantial uncertainty about any independent association of Helicobacter pylori infection with dyspepsia, and about any benefits of antibiotic treatments for nonulcer or uninvestigated dyspepsia.

OBJECTIVES

To perform a systematic review of the literature to determine whether chronic infection with H pylori is relevant to nonulcer or uninvestigated dyspepsia.

METHODS

Observational studies of associations between H pylori and dyspepsia published before April 1999 and randomized trials of the effects of H pylori eradication on dyspepsia published before January 2000 were identified by computer-assisted literature searches of relevant journals, reference lists, and discussions with authors. Relevant data were abstracted from the published reports by 2 investigators according to a fixed protocol.

RESULTS

Thirty relevant observational studies were identified involving approximately 3392 patients with nonulcer dyspepsia, and 11 separate observational studies were identified, involving 6426 patients with uninvestigated dyspepsia. Reports of strong associations in small observational studies without appropriate adjustment for potential confounding factors were not generally confirmed by larger and better-designed studies. No studies have been reported, however, that can reliably confirm or exclude the existence of any weak associations. Twenty-two randomized trials of treatments against H pylori were found involving a total of 2340 patients with nonulcer dyspepsia, almost all with positive H pylori test results. Only a few of these trials involved effective antibacterial regimens with prolonged follow-up, and even these studies were too small to assess the possibility of moderate benefits.

CONCLUSION

The available evidence indicates that there is no strong association between H pylori and dyspepsia, but there is insufficient evidence to confirm or refute the existence of a modest association.

Analysis of p53-regulated gene expression patterns using oligonucleotide arrays

Oligonucleotide microarrays were employed to quantitate mRNA levels from a large number of genes regulated by the p53 transcription factor. Responses to DNA damage and to zinc-inducible p53 were compared for their transcription patterns in cell culture. A cluster analysis of these data demonstrates that genes induced by γ radiation, UV radiation, and the zinc-induced p53 form distinct sets and subsets with a few genes in common to all these treatments. Cell type- or cell line-specific p53 responses were detected. When p53 proteins were induced with zinc, the kinetics of induction or repression of mRNAs from p53-responsive genes fell into eight distinct classes, five different kinetics of induction, and three different kinetics of repression. In addition, low levels of p53 in a cell induced or repressed only a subset of genes observed at higher p53 levels. The results of this study demonstrate that the nature of the p53 response in diverse mRNA species depends on the levels of p53 protein in a cell, the type of inducing agent or event, and the cell type employed. Of 6000 genes examined for p53 regulatory responses, 107 induced and 54 repressed genes fell into categories of apoptosis and growth arrest, cytoskeletal functions, growth factors and their inhibitors, extracellular matrix, and adhesion genes.

Analysis of p53-regulated gene expression patterns using oligonucleotide arrays

Oligonucleotide microarrays were employed to quantitate mRNA levels from a large number of genes regulated by the p53 transcription factor. Responses to DNA damage and to zinc-inducible p53 were compared for their transcription patterns in cell culture. A cluster analysis of these data demonstrates that genes induced by gamma radiation, UV radiation, and the zinc-induced p53 form distinct sets and subsets with a few genes in common to all these treatments. Cell type- or cell line-specific p53 responses were detected. When p53 proteins were induced with zinc, the kinetics of induction or repression of mRNAs from p53-responsive genes fell into eight distinct classes, five different kinetics of induction, and three different kinetics of repression. In addition, low levels of p53 in a cell induced or repressed only a subset of genes observed at higher p53 levels. The results of this study demonstrate that the nature of the p53 response in diverse mRNA species depends on the levels of p53 protein in a cell, the type of inducing agent or event, and the cell type employed. Of 6000 genes examined for p53 regulatory responses, 107 induced and 54 repressed genes fell into categories of apoptosis and growth arrest, cytoskeletal functions, growth factors and their inhibitors, extracellular matrix, and adhesion genes.

IHG-2, a mesangial cell gene induced by high glucose, is human gremlin. Regulation by extracellular glucose concentration, cyclic mechanical strain, and transforming growth factor-beta1

We used cloning in silico coupled with polymerase chain reaction to demonstrate that IHG-2 is part of the 3'-untranslated region of gremlin, a member of the DAN family of secreted proteins that antagonize the bioactivities of members of the transforming growth factor (TGF)-beta superfamily. Mesangial cell gremlin mRNA levels were induced by high glucose, cyclic mechanical strain, and TGF-beta1 in vitro, and gremlin mRNA levels were elevated in the renal cortex of rats with streptozotocin-induced diabetic nephropathy in vivo. gremlin expression was observed in parallel with induction of bone morphogenetic protein-2 (BMP-2), a target for gremlin in models of cell differentiation. Together these data indicate that (a) IHG-2 is gremlin, (b) gremlin is expressed in diabetic nephropathy in vivo, (c) both glycemic and mechanical strain stimulate mesangial cell gremlin expression in vitro, (d) high glucose induces gremlin, in part, through TGFbeta-mediated pathways, and (e) Gremlin is a potential endogenous antagonist of BMPs within a diabetic glomerular milieu.

Rumen fermentation in lactating cows selected for milk fat content fed two forage to concentrate ratios with hay or silage

Sixteen multiparous cows, including eight rumen fistulated cows, were used in a 4x4 Latin square experiment designed to study dietary effects on rumen and blood parameters and milk production in cows differing in genetic capacity for milk fat content. Diets contained forage to concentrate ratios of 50:50 or 30:70 with either grass hay or silage as the forage. Ruminal fermentation was characterized by a high molar percentage of butyrate, 14 to 17%. Forage to concentrate ratio affected most rumen parameters, with the exception of the molar percentage of propionate (18 to 19%). The silage had a higher fiber degradation rate compared with hay. Compared to hay diets, silage diets had higher ruminal outflow rates, lower acetate:propionate ratios, and greater milk production with no differences in milk composition. Cows selected for low milk fat had higher molar percentages of propionate in the rumen. The low milk fat cows had higher milk production than cows selected for high milk fat but did not differ in milk fat yield. Cows fed the 30:70 diets had higher plasma insulin concentrations in response to a glucose challenge. The low milk fat cows had lower basal concentrations of insulin and lower insulin responses to a glucose challenge. Small changes in nutrient metabolism and supply were sufficient to influence milk production.

Intravenous ifosfamide/mesna is associated with depletion of plasma thiols without depletion of leukocyte glutathione

Depletion of cellular glutathione (GSH) enhances the efficacy of many anticancer agents in preclinical systems. Limited published data showing depletion of GSH in vitro and in patients by ifosfamide and/or mesna provided the rationale for a Phase I trial. Ifosfamide and mesna were infused over 24 and 36 h, respectively, at equal daily doses; carboplatin was given after ifosfamide to a target plasma area under the curve of 4 mg x min x ml(-1). Plasma and peripheral WBC thiols were quantitated by high-performance liquid chromatography. The dose of ifosfamide was escalated from 2 to 8 g/m2; the maximum tolerated dose was 6 g/m2. Significant depletion in plasma cysteine and homocysteine, precursors for GSH synthesis, was observed (maximum, 95% to >99% at 8 g/m2). Plasma mesna and cysteine/ homocysteine levels were inversely correlated; nadir levels of cysteine/homocysteine were maintained for several hours after ifosfamide infusion had stopped and while mesna infusion was continuing. In vitro coincubation experiments confirmed that mesna reduces these thiols from disulfides to sulfhydryls, which are readily cleared, as evidenced by the significantly increased rate of excretion of cysteine in urine. In contrast, ifosfamide/mesna treatment caused a moderate depletion of plasma GSH in only 60% of the patients, with a nadir at 24 h and recovery immediately after the end of ifosfamide infusion. The GSH depletion in these patients was not dose related. The profile of GSH recovery in plasma after ifosfamide and the fact that mesna could not reduce GSH disulfides in vitro suggest that the observed GSH depletion in plasma in 60% of the patients may be related to direct reactions of GSH with ifosfamide metabolites and/or mesna. Our results indicate that mesna is a modulator of GSH precursors and that a prolonged infusion of mesna may be required to achieve GSH precursor starvation and the consequent GSH depletion in cells.

A comparison of melanoma mortality among WWII veterans of the Pacific and European theaters

PURPOSE

To determine whether cutaneous melanoma is associated with past military service in tropical locations, as a test of the 'critical period' sunlight exposure hypothesis.

METHODS

Mortality data from a longitudinal follow-up study of 5524 former prisoners of war (POW) and 3713 non-POW veteran controls, all white male veterans of World War II (WWII), were examined to determine whether death attributed to melanoma was associated with history of military service in Pacific or European theaters during WWII or with POW status. Deaths from colon cancer were used as a comparison outcome.

RESULTS

During 50 years of follow-up, there were 18 deaths from melanoma and 83 deaths from colon cancer among the cohort. Melanoma mortality varied with theater of war and POW status, whereas colon cancer mortality was similar for all subgroups. Pacific War POWs were at the highest risk overall (odds ratio (OR), 3.35; 95% confidence interval (CI), 0.39-28.76), whereas veterans of the Pacific War had nearly the same risk of melanoma (OR, 1.04; 95% CI, 0.09-11.94) compared with veterans of the European War. European theater POWs had a higher risk than non-POW veterans (OR, 2.76; 95% CI, 0.31-24.81). None of these differences, however, were statistically significant.

CONCLUSIONS

To the extent that POW status is associated with higher sun exposure, these data are consistent with the hypothesis that exposure to high levels of solar radiation in young adulthood is associated with a higher risk of melanoma mortality.

HIV/AIDS and nutrition. Implications for disease management

As a result of major advances in treatment, persons with HIV/AIDS are living longer and requiring more care management. Effective management of HIV-infected patients with nutritional alterations can result in fewer secondary infections and hospital admissions, better clinical outcomes, and lower healthcare costs. In this article, nutritional alterations, interventions, and resources during the course of HIV disease and their implications for care management are discussed.

Enlarged cholinergic forebrain neurons and improved spatial learning in p75 knockout mice

The p75 low affinity neurotrophin receptor (p75) can induce apoptosis in various neuronal and glial cell types. Because p75 is expressed in the cholinergic neurons of the basal forebrain, p75 knockout mice may be expected to show an increased number of neurons in this region. Previous studies, however, have produced conflicting results, suggesting that genetic background and choice of control mice are critical. To try to clarify the conflicting results from previous reports, we undertook a further study of the basal forebrain in p75 knockout mice, paying particular attention to the use of genetically valid controls. The genetic backgrounds of p75 knockout and control mice used in this study were identical at 95% of loci. There was a small decrease in the number of cholinergic basal forebrain neurons in p75 knockout mice at four months of age compared with controls. This difference was no longer apparent at 15 months due to a reduction in numbers in control mice between the ages of 4 and 15 months. Cholinergic cell size in the basal forebrain was markedly increased in p75 knockout mice compared with controls. Spatial learning performance was consistently better in p75 knockout mice than in controls, and did not show any deterioration with age. The results indicate that p75 exerts a negative influence on the size of cholinergic forebrain neurons, but little effect on neuronal numbers. The markedly better spatial learning suggests that the function, as well as the size, of cholinergic neurons is negatively modulated by p75.

Psychosocial morbidity: the economic burden in a pediatric health maintenance organization sample

OBJECTIVES

To evaluate psychosocial morbidity in pediatric primary care and to determine displaced health care utilization.

DESIGN AND SETTING

A cross-sectional sample of parent-child dyads was screened using the Pediatric Symptom Checklist (PSC) at 6 pediatric sites of a health maintenance organization (HMO). Cost and utilization data were retrieved from regional databases for this sample.

PARTICIPANTS

Parent-child dyads from an HMO in northern California (N = 1840). The children ranged in age from 2 to 18 years.

RESULTS

In all, 13.0% of children exhibited psychosocial dysfunction. The rate of children's chronic illness was 18.4%. Multiple regression analyses measured utilization and cost of health and psychiatric care for the selected population for the previous year; the average log cost of health care per child was $393. The average health care cost for children with anxious, depressed symptoms was $805. Chronically ill children were the highest utilizers of health care, with an average log cost of $1138. When psychosocial dysfunction was present, regression models showed that health care spending was highest for young children.

CONCLUSIONS

Health care utilization was higher for children with psychosocial morbidity, was higher among younger children, and decreased with age as psychiatric costs progressively increased.

Renal itch

Renal itch is localized or generalized itch, affecting patients with chronic renal failure, where there is no primary skin disease and no systemic or psychological dysfunction that might cause pruritus. It does not result from raised serum urea levels. The prevalence of renal itch has increased with the growing population in chronic renal failure and is a considerable cause of morbidity. The prevalence of itch increases with deteriorating renal function but does not improve significantly with dialysis. The pruritus is independent of duration of dialysis or cause of renal failure. The aetiology of renal itch is unclear. There is little evidence of a major role for histamine and antihistamines are rarely beneficial. Hyperparathyroidism, abnormal cutaneous innervation and endogenous opioids have been postulated as contributory factors. Treatment of renal itch is difficult. Naltrexone, oral activated charcoal, UVB phototherapy and ondansetron have been shown to be effective. Topical capsaicin may be of benefit in patients with localized pruritus. The definitive treatment for renal itch remains renal transplantation.

Coronary heart disease in Filipino and Filipino-American patients: prevalence of risk factors and outcomes of treatment

BACKGROUND

Very little has been published on Filipino (F) or Filipino-American (FA) health. Nothing has been written about coronary risk factors and their relationship to outcomes of percutaneous coronary intervention or cardiac surgical treatment in this group. The purpose of this study was to analyze prospectively collected data at a center treating coronary artery disease in a large series of Filipino patients.

METHODS

From January 1, 1992 to December 1, 1996, 527 consecutive FA patients and 3,176 Caucasians (C) were identified from an ongoing cardiac database. In-hospital and late outcomes post discharge were evaluated and results between the FA and C groups were compared.

RESULTS

The FA population had a higher incidence of hypertension (79% vs. 61%, p < 0.0001) and diabetes (34.7% vs. 24.1%, p < 0.001) compared to C patients. Hypercholesterolemia was similar in both groups. Obesity (FA 12.2% vs. C 18.3%, p < 0.0001) and current smoking (FA 15.8% vs. C 21.5%, p < 0.001) were more common in the C patients. Age at presentation did not differ between groups. Morbidity and mortality were higher in the FA patients following intervention in the catheterization lab (4.2% vs. 1.3%, p < 0.01). Logistic regression showed that FA ethnicity was an independent predictor of death after catheterization laboratory intervention (p < 0.01), along with emergency procedure, depressed ejection fraction, history of myocardial infarction (MI) and age greater than 65. For coronary bypass surgery, mortality and rate of MI was similar in both groups. Late follow-up post discharge (mean 17 months, range 12Eth 68) was obtained on 90% and 89% of eligible FA and C patients, respectively. Occurrence of late death and MI did not differ between the groups. However, need for any reintervention (catheterization laboratory or surgical) was significantly higher in the FA patients (21.2% vs. 14. 9%, p < 0.001). Cox proportional hazard regression modeling showed that FA ethnicity was an independent predictor of need for late reintervention (p < 0.01), along with type of initial treatment, history of diabetes, presence of triple vessel disease, initial presentation with acute MI and age greater than 65.

CONCLUSION

Filipino-Americans have a higher prevalence of hypertension and diabetes, and a lower prevalence of smoking and obesity compared to Caucasians. FA ethnicity is an independent predictor of higher mortality after catheterization laboratory intervention and increased need for late reintervention. However, the rate of late MI and death in FA was similar to C patients. These results suggest that FA patients, especially those presenting with diabetes for CAD treatment, need to be followed closely after percutaneous intervention or cardiac surgery procedures.

Health, body condition and blood metabolites in reindeer after submaintenance feed intake and subsequent feeding

The transition from experimentally induced poor nutritional conditions to feeding was studied with 69 eight-month-old female reindeer (Rangifer tarandus tarandus). During a pre-experimental period, all reindeer were fed a simulated winter diet with 80% lichens Cladina spp. and 20% Vaccinum myrtillus shrubs and Salix spp. leaves (lichen diet) ad lib. The reindeer were divided into five groups. A control group (group C) was fed the lichen diet ad lib. throughout the experiment. Four groups were fed half of that ration for eight days and were then totally deprived of feed for one day (restriction period). During the following 34 days (feeding period) the groups were re-fed the lichen diet (group L), fed pelleted reindeer feed combined with either lichen (group PL) or grass silage (group PS), or fed silage with a gradually increasing addition of pellets (group SP). Weekly measurements of blood samples and body weighr showed that the control group remained clinically healthy and had stable blood plasma concentrations of protein, urea, glucose and insulin throughout the experiment, but they lost weight. At slaughter, before and after the restriction period, all animals had lost rumen-free body weight, but the reindeer fed a restricted amount of feed lost more than the control group. Also the plasma metabolites were affected by the restricted feeding, with increased concentrations of urea and decreased concentrations of glucose. Group L responded immediately to the ad lib. feeding with blood metabolite levels rapidly approaching those of group C. The body weight developments were similar in groups L and C. Although the feed rations were increased gradually, diarrhoea occurred in some animals belonging to groups PL and PS within the first week of the feeding period. All reindeer recovered, after antibiotic treatment of the worst affected animals. The PL and PS groups, which had high contents of metabolisable energy and crude protein in their diets, showed increased con-centtations of plasma protein, urea and insulin. At the end of the feeding period, these groups had increased their body and carcass weights and gained fat, whereas reindeer fed the lichen diet had lost weight. Severe health problems (malnutrition and so-called wet belly) occurred in group SP during the first weeks of feeding and led to loss of animals, and consequently the SP group was excluded from the remainder of rhe experiment. The general conclusion is that the lichen diet did not cause any digestive problems, but resulted in a continuous decline in body weight and small or deficient fat reserves. After the initial diarrhoea, feeding with diets comprising pellets from the start resulted in improved condition, expressed as increased body weight, fat gain and higher concentrations of plasma protein, urea and insulin in relation to the control group. The diet initially based on grass in the form of silage of the given quality seemed insufficient as feed to reindeer calves in a poor nutritional state.

Tolerability and side-effects of post-exposure prophylaxis for HIV infection

A study of HIV post-exposure prophylaxis in 28 recipients showed that indinavir-containing regimens were poorly tolerated. This finding has implications for compliance and efficacy of the currently recommended combinations.

Endogenous IGF-1 regulates the neuronal differentiation of adult stem cells

Stem cells from the adult forebrain of mice were stimulated to form clones in vitro using fibroblast growth factor-2 (FGF-2). At concentrations above 10 ng/ml of FGF-2, very few clones gave rise to neurons; however, if FGF-2 was removed after 5 days, 20-30% of clones subsequently gave rise to neurons. The number of neuron-containing clones and the number of neurons per clone was significantly enhanced, if insulin-like growth factor (IGF)-1 or heparin were added subsequent to FGF-2 removal. The spontaneous production of neurons after FGF-2 removal was shown to be due to endogenous IGF-1, since antibodies to IGF-1 and an IGF-1 binding protein totally inhibited neuronal production. Similarly, these reagents also abrogated the neuron-promoting effects of heparin. Thus, it appears that endogenous IGF-1 may be a major regulator of stem cell differentiation into neurons. Furthermore, it was found that high levels of IGF-1 or insulin promoted the maturation and affected the neurotransmitter phenotype of the neurons generated.

Cytokine-mobilized peripheral blood progenitor cells for allogeneic reconstitution of miniature swine

BACKGROUND

Because of the relative ease of acquisition, increased yield, and improved engraftment characteristics, mobilized peripheral blood progenitor (stem) cells (PBSCs) have recently become the preferred source for hematopoietic stem cell transplantation. In our laboratory, procurement of a megadose of PBSCs is necessary for on-going studies evaluating non-myelosuppressive transplant regimens for the induction of mixed chimerism and allograft tolerance. To exploit hematopoietic growth factor synergy, we have sought to combine growth factors with proven utility to improve PBSC mobilization and maximize our PBSC procurement through an automated collection procedure.

METHODS

Mobilization characteristics of PBSCs were determined in 2-5-month-old miniature swine. Animals received either swine recombinant stem cell factor (pSCF, 100 microg/kg) and swine recombinant interleukin 3 (pIL-3, 100 microg/kg), administered intramuscularly for 8 days, or pSCF, pIL-3, and human recombinant granulocyte-colony stimulating factor (hG-CSF), at 10 microg/kg. Leukapheresis was performed beginning on day 5 of cytokine treatment and continued daily for 3 days.

RESULTS

Collection of PBSCs from cytokine-mobilized animals via an automated leukapheresis procedure demonstrated a 10-fold increase in the number of total nucleated cells (TNC) (20-30 x 10(10) TNC) compared to bone marrow harvesting (2-3 x 10(10) total TNC). A more rapid rise in white blood cells (WBCs) was seen after administration of all three cytokines compared to pSCF and pIL-3 alone. An increase in colony-forming unit granulocyte-macrophage frequency measured daily from peripheral blood during cytokine treatment, was seen with the addition of hG-CSF to pSCF/pIL-3 correlating well with the rise in WBCs. Similarly, the addition of hG-CSF demonstrated a notable increase in the median progenitor cell yield from the 3-day leukapheresis procedure. Cytokine-mobilized PBSCs were capable of hematopoietic reconstitution. PBSCs mobilized with pSCF/pIL-3 were infused into an SLA-matched recipient conditioned with cyclophosphamide (50 mg/kg) and total body irradiation 1150 cGy. Neutrophil and platelet engraftment occurred on days 5 and 7, respectively, with minimal evidence of graft-versus-host disease. Complete donor chimerism has been demonstrated 331 days after transplant.

CONCLUSIONS

Our preliminary results show that in this well-defined miniature swine model, recombinant swine cytokine combinations (pSCF, pIL-3 with or without hG-CSF) successfully mobilize a high yield of progenitor cells for allogeneic transplantation. Furthermore, these cytokine-mobilized PBSCs demonstrate the potential to reconstitute hematopoiesis and provide long-term engraftment in miniature swine.

Evaluation of thresholds for benomyl- and carbendazim-induced aneuploidy in cultured human lymphocytes using fluorescence in situ hybridization

Threshold mechanisms of activity for mutagenic agents have been debated for some time, especially for those substances which induce aneuploidy by inhibiting mitotic spindle function. No observed effect levels (NOELs) or "practical thresholds" have been demonstrated for several aneugens both in vitro and in vivo generally by either counting chromosomes in metaphase preparations or by observing micronuclei. Recently, fluorescence in situ hybridization (FISH) has proven to be a sensitive and useful technique for the assessment of aneuploidy at low concentrations. Using binucleate human lymphocytes coupled with FISH, we have been able to characterize a threshold mechanism of action for two spindle inhibitors, benomyl and its active metabolite, carbendazim. Test chemicals were added 24 h following culture initiation. After a further 20 h, cytochalasin B was added, and cells were harvested 28 h later (72 h post initiation). The distribution of chromosomes between the nuclei of binucleate cells was evaluated by fluorescence microscopy for the simultaneous detection of centromeres labeled with FITC (green) or Cy-3 (red). Six human chromosomes were investigated in pairs (1 and 8, 11 and 18, and X and 17). Abnormalities were classified as chromosome loss (including centromeric positive micronuclei), chromosome gain, non-disjunction, or polyploidy. Dose-response data were generated over a range of closely spaced concentrations at 100 ng/ml intervals. The threshold, defined as the lowest "effect" concentration using statistical methods, was determined for each chromosome. Non-disjunction proved to be the most sensitive endpoint for the detection of aneuploidy occurring at higher frequencies and lower concentrations. Results for the six chromosomes demonstrated similar dose-response data which included a series of concentrations with no statistically significant increase above background, followed by a second range of higher concentrations with a statistically significant, concentration-dependent increase. Nearly equimolar threshold concentrations were determined for benomyl- and carbendazim-induced non-disjunction.

Peptic ulcer bleeding: accessory risk factors and interactions with non-steroidal anti-inflammatory drugs

AIMS

To determine risk factors for peptic ulcer bleeding other than non-steroidal anti-inflammatory drugs (NSAIDs). Methods-Data on possible antecedent risk factors obtained in a large case control study of 1121 patients admitted to hospitals in Glasgow, Newcastle, Nottingham, Oxford, and Portsmouth with bleeding peptic ulcers were compared with the same information obtained in 989 population controls. Data were analysed by logistic regression with the calculation of odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

From a logistic regression model, oral anticoagulants (OR 7. 8; 95% CI 2.8-21.5), previous peptic ulcer (3.8; 2.6-4.9), treatment for heart failure (5.9; 2.3-13.1), oral corticosteroid use (2.7; 1. 3-4.5), treatment for diabetes (3.1; 1.2-4.3), and current smoking (1.6; 1.2-2.0) were all independent risk factors. No association was found with use of calcium channel antagonists. Odds ratios for concomitant NSAID usage were multiplicative with the exception of current smoking.

CONCLUSIONS

Some 45% of admissions for peptic ulcer bleeding in England and Wales in those aged 60 or more are calculated to be attributable to, or associated with, these accessory risk factors, which, together with those associated with aspirin or other NSAID use will account for over 80% of predisposing factors to ulcer bleeding.