156 resultados para General Chemistry


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A markedly elevated circulating CEA level was observed in January 1978 in a 40-year-old male patient who complained of functional digestive disorders consisting of 2-3 bowel movements at the end of each night. During follow-up of more than 3 years the CEA level was always found to be higher than 300 ng/ml as determined on 12 different blood samples using 3 different assays: the Hansen assay, our own inhibition radioimmunoassay performed on perchloric acid extract of serum, and a newly developed solid phase non-competitive enzyme immunoassay involving monoclonal anti-CEA antibody. The clinical evolution showed no aggravation of the persistent but mild bowel troubles, i.e. no real diarrhea or blood in the stool. The patient enjoys excellent general health and shows no weight loss. Barium enema, colonoscopy and extensive investigation by computerized axial tomography showed no evidence of primary or metastatic tumor. Apart from CEA, the blood chemistry was within normal limits. Six members of the patient's family have normal CEA levels. A possible explanation for this unique case of marked and persistent elevation of circulating CEA without evidence of cancer is discussed.

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When massively expressed in bacteria, recombinant proteins often tend to misfold and accumulate as soluble and insoluble nonfunctional aggregates. A general strategy to improve the native folding of recombinant proteins is to increase the cellular concentration of viscous organic compounds, termed osmolytes, or of molecular chaperones that can prevent aggregation and can actively scavenge and convert aggregates into natively refoldable species. In this study, metal affinity purification (immobilized metal ion affinity chromatography [IMAC]), confirmed by resistance to trypsin digestion, was used to distinguish soluble aggregates from soluble nativelike proteins. Salt-induced accumulation of osmolytes during induced protein synthesis significantly improved IMAC yields of folding-recalcitrant proteins. Yet, the highest yields were obtained with cells coexpressing plasmid-encoded molecular chaperones DnaK-DnaJ-GrpE, ClpB, GroEL-GroES, and IbpA/B. Addition of the membrane fluidizer heat shock-inducer benzyl alcohol (BA) to the bacterial medium resulted in similar high yields as with plasmid-mediated chaperone coexpression. Our results suggest that simple BA-mediated induction of endogenous chaperones can substitute for the more demanding approach of chaperone coexpression. Combined strategies of osmolyte-induced native folding with heat-, BA-, or plasmid-induced chaperone coexpression can be thought to optimize yields of natively folded recombinant proteins in bacteria, for research and biotechnological purposes.

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STUDY OBJECTIVES: To evaluate the association between objective sleep measures and metabolic syndrome (MS), hypertension, diabetes, and obesity. DESIGN: Cross-sectional study. SETTING: General population sample. PARTICIPANTS: There were 2,162 patients (51.2% women, mean age 58.4 ± 11.1). INTERVENTIONS: Patients were evaluated for hypertension, diabetes, overweight/obesity, and MS, and underwent a full polysomnography (PSG). MEASUREMENTS AND RESULTS: PSG measured variables included: total sleep time (TST), percentage and time spent in slow wave sleep (SWS) and in rapid eye movement (REM) sleep, sleep efficiency and arousal index (ArI). In univariate analyses, MS was associated with decreased TST, SWS, REM sleep, and sleep efficiency, and increased ArI. After adjustment for age, sex, smoking, alcohol, physical activity, drugs that affect sleep and depression, the ArI remained significantly higher, but the difference disappeared in patients without significant sleep disordered breathing (SDB). Differences in sleep structure were also found according to the presence or absence of hypertension, diabetes, and overweight/obesity in univariate analysis. However, these differences were attenuated after multivariate adjustment and after excluding subjects with significant SDB. CONCLUSIONS: In this population-based sample we found significant associations between sleep structure and MS, hypertension, diabetes, and obesity. However, these associations were cancelled after multivariate adjustment. We conclude that normal variations in sleep contribute little if any to MS and associated disorders.

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BACKGROUND: Changes in antihypertensive drug treatment are paramount in the adequate management of patients with hypertension, still, there is little information regarding changes in antihypertensive drug treatment in Switzerland. Our aim was to assess those changes and associated factors in a population-based, prospective study. METHODS: Data from the population-based, CoLaus study, conducted among subjects initially aged 35-75 years and living in Lausanne, Switzerland. 772 hypertensive subjects (371 women) were followed for a median of 5.4 years. Data Subjects were defined as continuers (no change), switchers (one antihypertensive class replaced by another), combiners (one antihypertensive class added) and discontinuers (stopped treatment). The distribution and the factors associated with changes in antihypertensive drug treatment were assessed. RESULTS: During the study period, the prescription of diuretics decreased and of ARBs increased: at baseline, diuretics were taken by 46.9% of patients; angiotensin receptor blockers (ARB) by 44.7%, angiotensin converting enzyme inhibitors (ACEI) by 28.8%, beta-blockers (BB) by 28.0%, calcium channel blockers (CCB) by 18.9% and other antihypertensive drugs by 0.3%. At follow-up (approximately 5 years later), their corresponding percentages were 42.8%, 51.7%, 25.5%, 33.0% 20.7% and 1.0%. Among all participants, 54.4% (95% confidence interval: 50.8-58.0) were continuers, 26.9% (23.8-30.2) combiners, 12.7% (10.4-15.3) switchers and 6.0% (4.4-7.9) discontinuers. Combiners had higher systolic blood pressure values at baseline than the other groups (p < 0.05). Almost one third (30.6%) of switchers and 29.3% of combiners improved their blood pressure status at follow-up, versus 18.8% of continuers and 8.7% of discontinuers (p < 0.001). Conversely, almost one third (28.3%) of discontinuers became hypertensive (systolic ≥140 mm Hg or diastolic ≥90 mm Hg), vs. 22.1% of continuers, 16.3% of switchers and 11.5% of combiners (p < 0.001). Multivariate analysis showed baseline uncontrolled hypertension, ARBs, drug regimen (monotherapy/polytherapy) and overweight/obesity to be associated with changes in antihypertensive therapy. CONCLUSION: In Switzerland, ARBs have replaced diuretics as the most commonly prescribed antihypertensive drug. Uncontrolled hypertension, ARBs, drug regimen (monotherapy or polytherapy) and overweight/obesity are associated with changes in antihypertensive treatment.