Allyl fluoride copolymers

Allyl fluoride can be copolymerized with vinyl chloride, vinyl acetate, ethyl acrylate, or SO₂ using free radical types of initiation. The copolymerization of allyl fluorida with vinyl chloride is comparable to the free radical initiated copolymerization of propylene with vinyl chloride. The allyl fluoride-vinyl acetate couple tends to form completely random copolymers, the reactivity ratios of the monomers being close to unity.     

Incidence and risk factors for serious hypoglycemia in older persons using insulin or sulfonylureas

BACKGROUND: Our knowledge about the risk of hypoglycemia associated with diabetes treatment is derived from studies that often exclude frail, elderly persons. OBJECTIVE: To determine the incidence and risk factors for developing serious hypoglycemia among older persons using sulfonylureas or insulin. METHODS: We conducted a population-based, retrospective cohort study of 19932 Tennessee Medicaid enrollees, aged 65 years or older, who used insulin or sulfonylureas from 1985 through 1989. The main end point was serious hypoglycemia defined as a hospitalization, emergency department admission, or death associated with hypoglycemic symptoms and a concomitant blood glucose determination of less than 2.8 mmol/L (< 50 mg/dL). RESULTS: We identified 586 persons with a first episode of serious hypoglycemia during 33,048 person-years of insulin or sulfonylurea use. The crude rates (per 100 person-years) of serious hypoglycemia were 1.23 (95% confidence interval [CI], 1.08-1.38) in users of sulfonylureas and 2.76 (95% CI, 2.47-3.06) among insulin users. Recent hospital discharge was the strongest predictor of subsequent hypoglycemia in older persons with diabetes. The adjusted relative risk of serious hypoglycemia occurring in days 1 through 30 after hospital discharge was 4.5 (95% CI, 3.5-5.7) compared with the risk associated with a hypoglycemic event occurring 366 or more days after hospital discharge. Other independent risk factors included advanced age (relative risk, 1.8; 95% CI, 1.4-2.3), black race (relative risk, 2.0; 95% CI, 1.7-2.4), and use of 5 or more concomitant medications (relative risk, 1.3; 95% CI, 1.1-1.5). CONCLUSIONS: In this population, the incidence of serious hypoglycemia is approximately 2 per 100 person-years, suggesting that many older adults can be safely treated with hypoglycemic drugs. Frail, elderly persons--the oldest-old, those using multiple medications, and those who are frequently hospitalized--are at a higher risk for drug-associated hypoglycemia. Such individuals may benefit from intensive education about the symptoms of hypoglycemia and close monitoring for adverse events related to diabetes treatment.     

Poly(ethylene glycol) fluorescent linkers

The first examples of PEG linkers containing the highly fluorescent dansyl group have been synthesized. Quantum yields of these PEG fluorescent linkers (PFL) were determined and utilized in calculating the PEG number of various protein conjugates. The method was also shown to be applicable to lower molecular weight drugs as exemplified by taxol.     

The influence of polyethylene glycol conjugation on bovine hemoglobin's intrinsic effect on the gastrointestinal system of the rat

The purpose of this study was to determine the impact of polyethylene glycol (PEG) conjugation on bovine hemoglobin's effect on gastrointestinal (GI) blood flow and motility in the Sprague Dawley rat. This study was divided into two parts: part one assessed blood flow, while the other evaluated bolus transit time through the GI. To examine blood flow, thirty-two rats were divided into four experimental groups (PEG-hemoglobin, bovine hemoglobin, Ringer's Lactate and autologous blood sham). Blood flow within the superior mesenteric artery was monitored during graduated isovolemic hemodilution. In the second part of the study, GI motility was estimated by bolus transit time. Thirty-six rats were assigned to four groups (PEG-hemoglobin, bovine hemoglobin, Ringer's Lactate and no treatment sham) and following an overnight fast, the rats were given a bolus injection (25 mL/kg) of test article. Three hours following injection, they received an oral 0.3 mL gavage of a charcoal/arabic gum mixture and were later sacrificed and their GI tract evaluated. Results indicated that the infusion of bovine hemoglobin reduced both baseline blood flow through the mesenteric artery and gastrointestinal transit time. In contrast, PEG-hemoglobin maintained baseline blood flow through the mesenteric artery and had no effect on GI transit time or morphology. Therefore, PEG conjugation of bovine hemoglobin significantly attenuated its intrinsic effect on the GI system of the rat.     

The Oxidative Dehydrogenation of Ethylbenzene. Cobalt Molybdate Catalysts

The role of the catalyst and feed composition in the conversion and product distribution in the oxidative dehydrogenation of ethylbenzene, using a series of cobalt molybdate catalysts, was investigated.     

Development of membranes and resins for piezodialysis

For piezodialysis to become a useful water desalination process, the most critical requirement is the development of appropriate membranes. The membrane presently being sought is a mosaic of cation-passing and anion-passing resins, each resin having a high degree of coupling between the mobile counterions and water. Of a wide variety of possible fabrication techniques, three are of particular interest: phase separation, pattern molding and latex-polyelectrolyte fabrication. The latex-polyelectrolyte fabrication technique has produced membranes which bring piezodialysis close to practical reality.     

Diuretic-based treatment and cardiovascular events in patients with mild renal dysfunction enrolled in the systolic hypertension in the elderly program

BACKGROUND: It is expected that the treatment of hypertension in patients with renal disease decreases the risk of cardiovascular events, but the evidence in these patients is lacking. OBJECTIVE: To assess the effect of diuretic-based treatment on cardiovascular events in patients with isolated systolic hypertension and renal dysfunction. METHODS: A total of 4336 persons aged 60 years and older with systolic blood pressures of 160 mm Hg and higher and diastolic blood pressures of less than 90 mm Hg were randomly assigned to receive either placebo or chlorthalidone (12.5-25.0 mg/d), with the addition of atenolol (25-50 mg/d) or reserpine (0.05-0.10 mg/d) if needed, and observed for 5 years. The risk of first-occurring cardiovascular events, including stroke, transient ischemic attack, myocardial infarction, heart failure, coronary artery bypass surgery, angioplasty, aneurysm, endarterectomy, sudden death, or rapid death, was stratified according to baseline serum creatinine levels (35.4-84.0, 84.1-101.6, 101.7-119.3, and 119.4-212.2 micromol/L [0.4-0.9, 1.0-1.1, 1.2-1.3, and 1.4-2.4 mg/dL]). RESULTS: Systolic blood pressure reduction was not affected by baseline serum creatinine levels. Active treatment did not affect the risk of serum creatinine levels becoming elevated during follow-up. The risk of hypokalemia with active treatment decreased significantly with increasing baseline serum creatinine levels. In the 4 baseline serum creatinine groups, the relative risk (95% confidence interval) of cardiovascular events developing with active treatment was 0.73 (0.54-0.97), 0.63 (0.49-0.82), 0.62 (0.44-0.87), and 0.59 (0.38-0.91). The results were similar for the outcomes of stroke or coronary artery events and in analyses stratified by sex or age. CONCLUSION: Diuretic-based treatment of patients with isolated systolic hypertension prevents the development of cardiovascular events in older persons with mild renal dysfunction.