Selective hydration of nitriles to amides catalysed by PCP pincer supported nickel(II) complexes.

The (PCP)Ni-OH complexes (R = (i)Pr, (t)Bu, Cy) are effective catalyst precursors for the selective hydration of nitriles to the corresponding amides under relatively mild conditions (80 °C) and low catalyst loadings (0.05-0.5%). Substrate scope includes aliphatic, vinylic and aromatic nitriles, but substrates with protic groups poison the catalyst abruptly. The catalysts are effective because the electron rich nature of the PCP ligands and their steric bulk renders the hydroxo group labile.

Cell attachment to laser-induced AAm- and HEMA-grafted ethylene-propylene rubber as biomaterial: in vivo study.

With the purpose of improved tissue compatibility, ethylene-propylene rubber (EPR)-based vulcanizates have been surface grafted with acrylamide (AAm) and 2-hydroxyethyl methacrylate (HEMA) using CO2-pulsed laser as excitation source. Grafted surfaces were characterized by performing scanning electron microscopy combined with energy dispersive X-ray analysis and attenuated total reflectance infrared spectroscopy to study the surface morphology and grafting. Surface hydrophilicity (measured by water drop contact angle) increased for the grafted samples. Fractal type of morphology is formed by the grafted poly(AAm) and poly(HEMA) chains on the surface of EPR, which provides both hydrophilic and hydrophobic sites. In vivo tissue compatibility was assessed by implanting test samples in the deep intramuscular and peritoneal layers of rabbits. After 8 weeks of implantation, comparative results indicate that the adhesion of macrophages to EPR samples modified with AAm and HEMA, with no respiratory burst and cellular damage, is significantly lower than their adhesion on unmodified surfaces which show an activated state of the attached macrophages. Also, no acute or chronic inflammatory reaction was observed at the site of implantation and a thinner fibrous tissue capsule formed around the modified samples, whereas foreign body giant cells adhered to unmodified EPR.

Clinical efficacy of force titrated doses of diltiazem extended-release. A placebo controlled study.

Thirty patients with clinical and ambulatory essential hypertension were treated in a double-blind fashion with force titrated doses of placebo or diltiazem once daily (OD) extended-release (ER) 120, 240, 360, and 540 mg to characterize the full-dose range of the new formulation. An incremental dose-response effect was observed both in clinic and ambulatory blood pressure parameters. Doses of > or = 240 mg significantly decreased clinic diastolic blood pressure, whereas systolic blood pressure was significantly lowered by the 540-mg dose. Moreover, compared with placebo, ambulatory blood pressure was significantly decreased by the 360- and 540-mg dose levels. Trough/peak ratios for systolic and diastolic blood pressures were 50% and higher at dose levels of 240 mg and above. Adverse reactions with diltiazem OD ER were generally mild and similar to those observed with placebo. The findings of this study indicate that the most favorable effects of diltiazem OD ER were observed in response to the 360- and 540-mg dose levels. The dose escalation forced titration study design appears to be a valuable tool in obtaining rigorous dose-response data of new antihypertensive agents.

Lipid and lipoprotein changes associated with oral contraceptive use: a randomized clinical trial.

To determine the effects of oral contraceptives on lipids and lipoproteins over a six-month period, we randomized 266 women into four oral contraceptive groups: ethinyl estradiol 35 micrograms plus ethynodiol diacetate 1 mg, ethinyl estradiol 30 micrograms plus levonorgestrel 0.15 mg, ethinyl estradiol 35 micrograms plus norethindrone 1 mg, and ethinyl estradiol 35 micrograms plus norethindrone 0.5 and 1 mg (biphasic). For all groups, total cholesterol increased 5.9-9.1% from baseline values over the six months. Triglycerides increased with all preparations, with the ethynodiol diacetate group (37.6%) and the biphasic norethindrone group (45.3%) showing the greatest increase. Low-density lipoprotein cholesterol increased 10-15.6% among the groups; low-density lipoprotein-apolipoprotein B changed proportional to the low-density lipoprotein cholesterol increases. All groups except the ethynodiol diacetate group showed a decrease of high-density lipoprotein cholesterol, with the levonorgestrel group (8.7%) and biphasic norethindrone group (4.5%) showing the largest declines. Apolipoprotein A-1 increased in all groups, with the ethynodiol diacetate preparation (19.3%) showing the greatest increase and the levonorgestrel preparation (3.2%) showing the smallest increase from baseline values. The changes in apolipoprotein A-1 were out of proportion to the changes in high-density lipoprotein cholesterol, suggesting that the high-density lipoprotein particle may be undergoing some type of metabolic alteration.

Experimental procedure for the manufacture and calibration of polyacrylamide gel (PAG) for magnetic resonance imaging (MRI) radiation dosimetry.

A simple methodology for the manufacture and calibration of polyacrylamide gel (PAG) for magnetic resonance imaging (MRI) radiation dosimetry is presented to enable individuals to undertake such work in a routine clinical environment. Samples of PAG were irradiated using a linear accelerator and imaged using a 0.5 T (22 MHz) Philips Gyroscan MRI scanner. The mean spin-lattice relaxation rate was measured using a 'turbo-mixed' sequence, consisting of a series of 90 degrees pulses, each followed by acquisition of a train of spin echoes. The mean sensitivity for five different batches of PAG in the range up to 10 Gy was calculated to be 0.0285 s-1 Gy-1 for the mean spin-lattice relaxation rate with a percentage standard deviation of 1.25%. The overall reproducibility between batches was calculated to be 2.69%. This methodology, which introduces the novel use of pre-filled nitrogen vials for calibration, has been used to develop techniques for filling anatomically shaped anthropomorphic phantoms.

The relationship between diagnostic information available at admission and discharge for patients in one PSRO setting: implications for concurrent review.

Professional Standards Review Organization (PSRO) operating guidelines recommend the use of Professional Activity Study (PAS) length of stay norms for conducting concurrent review. These norms, determined by aggregating discharge abstracts from PAS hospitals in the same United States census region, are assigned to patients based only on information known at admission. This study investigated the relationship between patient information available at admission and the information available at discharge in light of its effects on the concurrent review process. Analyzing 52,210 patient records from 68 hospitals in one PSRO setting, it was found that changes in patients' primary diagnosis resulted in changes in their PAS diagnostic category for 41.3 per cent of the patients. A change in PAS diagnostic caetgory after the assignment of the review norm resulted in missed and unnecessary reviews as well as early and late reviews. These findings indicate that there are serious operational problems with the current method of performing concurrent review.

The effect of topical L-selenomethionine on minimal erythema dose of ultraviolet irradiation in humans.

The purpose of this study was to determine whether topical L-selenomethionine reduces the degree of acute damage to the skin (i.e., sunburn) induced by ultraviolet (UV) irradiation in humans. Eight women volunteers were treated for 2 weeks first with lotion vehicle then with topical L-selenomethionine for two weeks at each of three concentrations (0.002%, 0.02%, and 0.05%). At the end of each 2-week treatment period, the minimal erythema dose (MED) of UV irradiation was measured using a Multiport Solar Ultraviolet Simulator. It was found that topical L-selenomethionine was effective in protecting against acute UV damage to the skin. A response curve demonstrated that increasing concentrations of topical L-selenomethionine gave increasing MED, with a plateau of maximal protection attained at a concentration between 0.02% and 0.05%. Although previous studies in rats and mice demonstrated percutaneous absorption of selenium after application of L-selenomethionine, in the concentrations used here, the topical L-selenomethionine did not result in increased levels of selenium in the blood plasma of the patients tested.

Biocompatibility evaluation of laser-induced AAm and HEMA grafted EPR. Part 1: In-vitro study.

Samples based on ethylene-propylene rubber (EPR) have been surface grafted with acrylamide (AAm) and 2-hydroxyethyl methacrylate (HEMA) using CO2-pulsed laser as a stimulation source. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDXA) and attenuated total reflectance infrared (ATR-IR) spectra were performed on the modified samples. These techniques revealed the formation of grafted poly(AAm) and poly(HEMA) on the surface of EPR. The surface grafted poly(AAm) and poly(HEMA) were found to have a fractal type of morphology. EDXA showed insignificant grafted AAm and HEMA in regions where fractals were absent. Fractal patterned surfaces provide hydrophilic and hydrophobic sites, making EPR suitable as a biomaterial. In-vitro adhesion and spreading of alveolar macrophages (AMs) cultured on the surface of modified samples have been evaluated by hemocytometry and SEM, respectively, and compared with unmodified controls. Relationships between AM adhesion and their spreading, with surface morphology, graft level and water compatibility are also discussed. Generally, more AMs attach onto unmodified surfaces with a greater degree of spreading, than on the modified EPR. Samples grafted between 0.7 mg/cm2 and 1 mg/cm2 showed fairly low AM density compared with both unmodified EPR and lightly modified samples (less than 0.2 mg/cm2). AMs cultured on the unmodified EPR were larger and displayed pronounced ruffling of the plasma membrane, an increased capacity for adherence and spreading on the surface, and an increased number of extensive filopodia. Moreover, AMs attached onto the surface of modified samples appeared rounded, with minimal cytoplasmic spreading and ruffling.