Spectrophotometric determination of methomyl residues in selected vegetables, grains, and soil

Methomyl (S-methyl-N-[(methylcarbamoyl) oxy] thioacetimidate) is converted to oxime and hydroxylamine by alkali and acid treatment, respectively. Hydroxylamine is oxidized with iodine in the presence of sulfanilic acid to yield p-diazoniumbenzenesulfonic acid which is coupled with alpha-naphthylamine to form a crimson p-benzenesulfonic acid-azo-alpha-naphthylamine with an absorption maximum at 520 nm. The relationship between absorbance and concentration of methomyl is linear in the range 0.5-10 microgram. The method is sensitive and specific; 0.625 ppm methomyl can be determined in a 40 g sample of selected vegetables, grains, and soil.     

Role of the Maillard reaction in aging of tissue proteins. Advanced glycation end product-dependent increase in imidazolium cross-links in human lens proteins

Dicarbonyl compounds such as glyoxal and methylglyoxal are reactive dicarbonyl intermediates in the nonenzymatic browning and cross-linking of proteins during the Maillard reaction. We describe here the quantification of glyoxal and methylglyoxal-derived imidazolium cross-links in tissue proteins. The imidazolium salt cross-links, glyoxal-lysine dimer (GOLD) and methylglyoxal-lysine dimer (MOLD), were measured by liquid chromatography/mass spectrometry and were present in lens protein at concentrations of 0. 02-0.2 and 0.1-0.8 mmol/mol of lysine, respectively. The lens concentrations of GOLD and MOLD correlated significantly with one another and also increased with lens age. GOLD and MOLD were present at significantly higher concentrations than the fluorescent cross-links pentosidine and dityrosine, identifying them as major Maillard reaction cross-links in lens proteins. Like the N-carboxy-alkyllysines Nepsilon-(carboxymethyl)lysine and Nepsilon-(carboxyethyl)lysine, these cross-links were also detected at lower concentrations in human skin collagen and increased with age in collagen. The presence of GOLD and MOLD in tissue proteins implicates methylglyoxal and glyoxal, either free or protein-bound, as important precursors of protein cross-links formed during Maillard reactions in vivo during aging and in disease.     

A novel membrane protein is a mouse mammary tumor virus receptor

Mouse mammary tumor virus (MMTV) infects a number of different cell types, including mammary gland and lymphoid cells, in vivo. To identify the cellular receptor for this virus, a mouse cDNA expression library was transfected into Cos-7 monkey kidney cells, and those transfected cells able to bind virus were selected by using antibody against the virus's cell surface envelope protein, gp52. One clone isolated from a library prepared from newborn thymus RNA, called MTVR, was able to confer virus binding to both monkey and human cells; this binding was blocked by anti-MTVR antibody. Moreover, transfection of MTVR into CV1 cells rendered them susceptible to infection by a murine leukemia virus-based retrovirus vector pseudotyped with the MMTV envelope protein. An epitope-tagged MTVR cofractionated with cellular membranes. Coimmunoprecipitation of the MMTV envelope protein and a MTVR-rabbit Fc fusion protein showed that these two proteins bound to each other. The MTVR sequence clone is unique, shows no homology to known membrane proteins, and is transcribed in many tissues.     

Communication problems for patients hospitalized with chest pain

In many settings, primary care physicians have begun to delegate inpatient care to hospitalists, but the impact of this change on patients' hospital experience is unknown. To determine the effect on physician-patient communication of having the regular outpatient physician (continuity physician) continue involvement in hospital care, we surveyed 1,059 consecutive patients hospitalized with chest pain. Patients whose continuity physicians remained involved in their hospital care were less likely to report communication problems regarding tests (20% vs 31%, p =.03), activity after discharge (42% vs 51%, p =.02), and health habits (31% vs 38%, p =. 07). In a setting without a designated hospitalist system, communication problems were less frequent among patients whose continuity physicians were involved in their hospital care. New models of inpatient care delivery can maintain patient satisfaction but to do so must focus attention on improving physician-patient communication.     

Studies in char gasification—III: The combustion zone

The fluidized bed steam-oxygen-char gasifier is modelled by treating the bed as one in which the solids are well mixed and the gases are in plug flow. This model permits a detailed analysis of the combustion zone. The entire reactor is assumed to be at a uniform temperature. From the results of the model calculations, it was concluded that the assumption of negligible combustion zone thickness made in the earlier two papers is acceptable This model predicts higher total carbon conversion and methane mole fraction in the product gas than the lumped model analysed in an earlier paper.     

Acute respiratory response to prolonged, moderate levels of sidestream tobacco smoke

Carefully controlled, clinical research has shown psychiatric rehabilitation to significantly help persons with severe mental illness address their disabilities and obtain a higher quality of life. For psychiatric rehabilitation to yield its greatest effect, discrete principles and skills that are part of the rehabilitation paradigm must be disseminated to staff working in real-world settings. Staff training strategies that help the rehabilitation team develop effective programs are especially important. This paper reviews Interactive Staff Training (IST), an approach to team building and program development that combines educational and organizational strategies. IST comprises four stages--introduction to the system, program development, program implementation, and program maintenance--with each stage defined by behavioral tasks that engage the team and corresponding products that serve as markers of progress. Testing treatment dissemination strategies poses interesting problems for the researcher, some which are reviewed here. Outcome studies completed on IST are summarized in light of these problems. The paper ends with a consideration of some future directions for research in this area.