Comparison between in vitro and in vivo UHMW-PE degradation.

There is an increasing interest in orthopedics for clinical problems associated with wear and failure of ultra-high-molecular-weight (UHMW) polyethylene devices. Wear not only affects the implant performance but, more importantly, produces the release of particulate debris in the surrounding tissues and fluids. The debris in turn cause a deleterious biological response that can include an inflammatory reaction with subsequent loosening of the implant components. Surface wear is certainly promoted from the oxidation process that can occur during the prosthesis life. However, the oxidation mechanism involved during the implantation period has not been described yet for the UHMW-polyethylene devices. Here, the comparison of FT-IR spectra of a retrieved acetabular cup (9 years in a human body) and thin UHMW-PE films treated respectively with: H2O2, KO2/THF, and Fe[II]/H2O2 solutions indicates the effect of the high reactive hydroxyl radicals as the most important cause of in vivo polymer degradation.

Rating satisfaction research: is it poor, fair, good, very good, or excellent?

Satisfaction is one of the core outcome measures for health care. It is intuitively more appealing than measures of health care effectiveness or efficiency that are more difficult to understand. Satisfaction with health care is a measure with a long history in the social sciences. Most current research is less interested in correlations between patient characteristics and satisfaction and more focused on improving the quality of care and service delivered to patients and health plan members. While this article provides a brief overview of historical satisfaction literature, the primary focus is on current trends in measuring satisfaction, including efforts by the National Committee for Quality Assurance and the Foundation for Accountability. Limitations of current satisfaction measures are discussed; alternatives to using satisfaction to understand the experience of the health care system are suggested.

Glutamate-1-semialdehyde aminotransferase from Sulfolobus solfataricus.

Glutamate-1-semialdehyde aminotransferase (GSA-AT) from the extremely thermophilic bacterium Sulfolobus solfataricus has been purified to homogeneity and characterized. GSA-AT is the last enzyme in the C5 pathway for the conversion of glutamate into the tetrapyrrole precursor delta-aminolaevulinate (ALA) in plants, algae and several bacteria. The active form of GSA-AT from S. solfataricus seems to be a homodimer with a molecular mass of 87 kDa. The absorption spectrum of the purified aminotransferase is indicative of the presence of pyridoxamine 5'-phosphate (PMP) cofactor, and the catalytic activity of the enzyme is further stimulated by addition of PMP. 3-Amino-2,3-dihydrobenzoic acid is an inhibitor of the aminotransferase activity. The N-terminal amino acid sequence of GSA-AT from S. solfataricus was found to share significant similarity with the eukaryotic and eubacterial enzymes. Evidence is provided that ALA synthesis in S. solfataricus follows the C5 pathway characteristic of plants, algae, cyanobacteria and many other bacteria.

Reduced regulatory thermogenesis in pregnant and ovariectomized women.

Diet-induced thermogenesis has been evaluated in five ovariectomized young women, five late pregnant (at the 8th month of pregnancy) and five age matched lean control women. Post-prandial thermogenesis was tested after a 900 Kcal mixed meal. Although pregnant (p less than 0.05) and ovariectomized showed a basal metabolic rate higher than control females, both groups had a significantly lower post-prandial thermogenesis when compared to the lean one (p less than 0.05). It is concluded that post-prandial thermogenesis is depressed in pregnant and ovariectomized females and that this condition may facilitate, at least in predisposed adult women, the development of obesity.

Effect of dietary fibre on postprandial thermogenesis.

The effect of fibre on postprandial thermogenesis was evaluated in seven healthy males (age 29.6 +/- 3.6 years, BMI 24.6 +/- 0.6 kg/m2) after they had ingested three isocaloric meals with different fibre contents: low fibre (Lfb) containing 8 g. dietary fibre; glucomannan (Glc), which was Lfb supplemented with 6 g glucomannan, a pectin-like fibre; and high fibre (Hfb) containing 26 g dietary fibre. Postprandial thermogenesis, evaluated for 6 h after the ingestion of food, was higher after the Lfb (82.3 +/- 5.4 kcal) than after the Hfb and Glc meals (69.4 +/- 6.8 and 61.4 +/- 8.4 kcal, respectively). Glucose and insulin responses were depressed over the first 2 h after the Hfb and Glc meals as compared to the Lfb meal. However, these differences disappeared when the whole 6 h postprandial period was considered. No major effects of the different fibre contents of the meals on postprandial triglyceride and FFA levels were detected. These results demonstrate that the fibre content of meals, besides the well known effect on energy intake, may also affect energy expenditure.