Activity of the plasma membrane H(+)-ATPase and optimal glycolytic flux are required for rapid adaptation and growth of Saccharomyces cerevisiae in the presence of the weak-acid preservative sorbic acid

The weak acid sorbic acid transiently inhibited the growth of Saccharomyces cerevisiae in media at low pH. During a lag period, the length of which depended on the severity of this weak-acid stress, yeast cells appeared to adapt to this stress, eventually recovering and growing normally. This adaptation to weak-acid stress was not due to metabolism and removal of the sorbic acid. A pma1-205 mutant, with about half the normal membrane H+-ATPase activity, was shown to be more sensitive to sorbic acid than its parent. Sorbic acid appeared to stimulate plasma membrane H+-ATPase activity in both PMA1 and pma1-205. Consistent with this, cellular ATP levels showed drastic reductions, the extent of which depended on the severity of weak-acid stress. The weak acid did not appear to affect the synthesis of ATP because CO2 production and O2 consumption were not affected significantly in PMA1 and pma1-205 cells. However, a glycolytic mutant, with about one-third the normal pyruvate kinase and phosphofructokinase activity and hence a reduced capacity to generate ATP, was more sensitive to sorbic acid than its isogenic parent. These data are consistent with the idea that adaptation by yeast cells to sorbic acid is dependent on (i) the restoration of internal pH via the export of protons by the membrane H+-ATPase in an energy-demanding process and (ii) the generation of sufficient ATP to drive this process and still allow growth.     

Interest of epitopic dissection in immunoanalysis of proteins and peptides: review of theoretical and practical aspects

AIM: To assess cell proliferation in early prostate cancer and associated pathological lesions. METHODS: Using the Ki-67 antibody, the cell proliferation index was measured in early stage prostatic carcinoma in 37 incidental tumours diagnosed at transurethral prostatectomy (TURP) and in 20 low volume cancers treated by radical prostatectomy. Proliferation indexes have also been measured in areas of normal peripheral zone, transition zone hyperplasia, atrophic appearing lobules, and high grade prostatic intraepithelial neoplasia in the radical prostatectomy cases. RESULTS: In the TURP series the proliferation index correlated with grade and stage. Logistic regression analysis, however, showed that Gleason grade was the most reliable predictor of biopsy proven residual disease and clinical progression. In the radical series transition zone carcinoma the proliferation index was half that of peripheral zone carcinoma. The atrophic lobules also showed a high proliferation index of the same order as seen in the peripheral zone carcinoma. Normal peripheral zone showed the lowest proliferation index and in hyperplastic transition zone it was also less than the other areas. CONCLUSIONS: There is only limited support for the correlation of proliferation index with grade in early stage prostatic carcinoma. The findings do not suggest that proliferation index adds to the prognostic information given by grade and stage in pT1 disease. The significant difference in proliferation index in transition zone and peripheral zone carcinomas supports the morphological distinction of these tumour types and is consistent with differences in biological behaviour. The high proliferation index in lobules considered morphologically atrophic is reminiscent of previous observations in which carcinoma was spatially associated with atrophy.     

Gastrointestinal lavage reduces total body water

BACKGROUND: The aim of this study was to measure changes in total body water (TBW) in surgical patients after gastrointestinal lavage. METHODS: In a prospective, controlled study we used bioelectrical impedance to calculate the change in TBW in two groups of general surgical patients in the pre-operative period: the colonic lavage group consisted of patients fasted overnight who received 3 L of gastrointestinal lavage solution (GLS; n = 30), and the control group consisted of patients fasted overnight only (n = 30). Total body water was measured before and after either lavage and fasting (lavage group) or fasting alone (control group). RESULTS: The lavage group had a mean TBW loss of 729 mL +/- s.e. 217 and the control group a mean loss of 84 mL +/- s.e. 93 (P < 0.01 unpaired t-test). CONCLUSIONS: The results suggest that GLS results in a net loss of TBW. Although this fluid loss is modest, it may be important in surgical patients who have minimal cardiovascular reserve.     

Evaluation of RU28318 and RU40555 as selective mineralocorticoid receptor and glucocorticoid receptor antagonists, respectively: receptor measures and functional studies

BACKGROUND: Australia has a high rate of cardiovascular disease mortality and also a significant proportion of migrants. Little is known about the morbidity experience or cardiovascular risk factors among the larger migrant groups, and this is especially true of the Arabic-speaking population. OBJECTIVES: The objectives of the study were to identify the health profile of Arabic-speaking people in Sydney, Australia, to explore the relationship between level of acculturation and health indicators and to identify the morbidity profile of patients presenting to Arabic-speaking general practitioners (GPs). DESIGN: Adult Arabic-speaking patients aged 18-70 years attending 20 Arabic-speaking GPs in Canterbury, Sydney, during the 2-week study period were asked to complete a self-administered questionnaire in Arabic or English while waiting to see the GP. Data on cardiovascular risk factors, level of acculturation and reasons for seeing the GP were collected. RESULTS: Data were collected from 851 patients (62% response rate). Almost three-quarters (73%) of males and 36% of females were considered overweight or obese (body mass index > 25). Of concern, 37% of males and 28% of females were smokers. Females were significantly less likely to have been tested for diabetes (p < .05) or raised blood pressure (p < 0.05) compared with females in NSW. Respondents consumed less bread per day and more fruits than in NSW overall. Respiratory complaints (flu and colds) were the most frequently reported reasons for patient encounters. Except for the youngest age group, males gave more reasons for encounters than females. CONCLUSIONS: Consecutive sampling of ethnic patients attending a GP who speaks their language holds promise as a method of needs assessment with migrant populations. Further, our results suggest that smoking and weight reduction programs are priorities in the Arabic-speaking community. These risk factors are ideal for intervention by GPs speaking the same language.     

Evaluation and treatment of the infected foot in a community teaching hospital

More inpatient hospital days are used for the care of diabetic foot infection than for any other diabetic sequela. Both the number of lower extremity amputations and the overall treatment cost of treating diabetic infections may be reduced by using a team approach in the care of the infected diabetic pedal wound. The authors propose an evaluation and treatment protocol of infected pedal ulcerations in an urban, community teaching institution when admitted to an established, multidisciplinary diabetic foot care team. The hospital course of 111 patients admitted with a primary diagnosis of infected pedal ulceration are retrospectively reviewed. Results revealed an average-length hospital stay of 7.4 days with a 96% limb-salvage rate. The authors suggest that in the treatment of the infected pedal wound, a diabetic foot care team with a well developed treatment protocol may yield a consistently favorable outcome and a cost-effective hospital course.     

Phenotypic analysis of antigen-specific T lymphocytes

Identification and characterization of antigen-specific T lymphocytes during the course of an immune response is tedious and indirect. To address this problem, the peptide-major histocompatability complex (MHC) ligand for a given population of T cells was multimerized to make soluble peptide-MHC tetramers. Tetramers of human lymphocyte antigen A2 that were complexed with two different human immunodeficiency virus (HIV)-derived peptides or with a peptide derived from influenza A matrix protein bound to peptide-specific cytotoxic T cells in vitro and to T cells from the blood of HIV-infected individuals. In general, tetramer binding correlated well with cytotoxicity assays. This approach should be useful in the analysis of T cells specific for infectious agents, tumors, and autoantigens.     

Metabolism and biochemical effects of 3,3',4,4'-tetrachlorobiphenyl in pregnant and fetal rats

The metabolism and distribution of a single oral dose of 25 mumol 14C-labelled 3,3',4,4'-tetrachlorobiphenyl (14C-TCB) were investigated in pregnant female Wistar rats and their fetuses. TCB was administered on day 13 of gestation and the elimination was followed for 7 days. Non-pregnant rats were treated similarly for comparison. Fecal elimination of 14C-TCB derived radioactivity was significantly lower in pregnant rats than in non-pregnant rats. The major metabolite found in adult liver and plasma, placental tissue, whole fetuses and fetal plasma was 3,3',4',5-tetrachloro-4-biphenylol (4-OH-TCB). Tissue levels (liver, abdominal fat, skin, skeletal muscle, kidney and plasma) of 14C-TCB-derived radioactivity declined by 65-85% over a 7-day period following administration in the adult animals. However, 14C-TCB-derived radioactivity accumulated more than 100-fold in the fetuses over the same time period, and GC/MS analysis revealed that the fetal accumulation in radioactivity was due primarily to 4-OH-TCB, and not the parent compound. On day 20 of gestation, concentrations of 4-OH-TCB were 14 times greater in fetal plasma than maternal plasma. Treatment with 14C-TCB significantly reduced plasma thyroxine levels by at least 28% up to 7 days after administration in non-pregnant animals and up to 4 days after administration in pregnant rats (31% decrease). By 7 days after administration plasma thyroxine levels had returned to control levels in the TCB-treated pregnant rats. However, fetal plasma thyroxine levels were significantly decreased by 35% in fetuses from 14C-TCB-treated dams 7 days after TCB administration. Hepatic microsomal ethoxyresorufin-O-deethylase (EROD) activity was significantly induced in TCB-treated dams relative to controls at 4 and 7 days after administration, while no EROD activity was detected in hepatic microsomes from control or TCB treated fetal rats at day 20 of gestation. These data suggest that hydroxylated metabolites of polychlorinated biphenyls may play a role in the development toxicity of these compounds.