Homogeneity of a supersaturated solid solution.

Extended x-ray absorption fine structures, small-angle x-ray scattering, and atomistic model calculations have been employed to probe the homogeneity of the fcc solution created in Ag-Cu, a classical system demonstrating the extension of solubility across the entire miscibility gap through rapid quenching. Our results reveal that in many cases the supersaturated solutions formed have decomposition features on the scale of 1 nm. Conventional diffraction methods are inadequate in determining the level of supersaturation or the uniformity of such solid solution alloys.

X-ray fluorescence mapping and micro-XANES spectroscopic characterization of exhaust particulates emitted from auto engines burning MMT-added gasoline.

The elemental distribution and compositional homogeneity in auto exhaust particulates emitted from methylcyclopentadienyl manganese tricarbonyl-(MMT-)added gasoline engines have been investigated using a newly installed synchrotron X-ray microprobe. Two representative groups of exhaust particulate matter, as defined in a recent bulk X-ray absorption fine structure (XAFS) spectroscopic study at the Mn K-edge, were studied. The micro-X-ray absorption near-edge structure (XANES) spectra indicate a relatively homogeneous distribution of phases within a given particulate sample, down to a spatial extent of 40 microm (the resolution of microprobe). The micro-XANES also enabled analysis of several areas which displayed compositions different from the bulk sample, supporting the general theory describing manganese species formation in the exhaust. The ability to evaluate small regions also enabled direct verification of manganese sulfate from the S XANES despite the vast excess of sulfur present in other forms. The presence of a chloride compound, introduced through the sample dilution air and engine intake air, was also revealed. The study demonstrates the value of the combined X-ray microfluorescence with excitation by polychromatic radiation for elemental mapping and micro-XANES spectroscopy for chemical speciation in the study of dilute environmental materials containing low-Z constituents such as Cl, S, and P.

Temporal trends in BMI among adults with diabetes.

OBJECTIVE: Increasing obesity within the general population has been accompanied by rising rates of diabetes. The extent to which obesity has increased among people with diabetes is unknown, as are the potential consequences for diabetes outcomes. RESEARCH DESIGN AND METHODS: Community medical records (hospital and ambulatory) of all Rochester, Minnesota, residents aged > or =30 years who first met standardized research criteria for diabetes from 1970 to 1989 (n = 1,306) were reviewed to obtain data on BMI and related characteristics as of the diabetes identification date (+/-3 months). Vital status as of 31 December 1999 and date of death for those who died were obtained from medical records, State of Minnesota death tapes, and active follow-up. RESULTS: As of the identification date, data on BMI were available for 1,290 cases. Of the 272 who first met diabetes criteria in 1970-1974, 33% were obese (BMI > or =30), including 5% who were extremely obese (BMI > or =40). These proportions increased to 49% (P < 0.001) and 9% (P = 0.012), respectively, for the 426 residents who first met diabetes criteria in 1985-1989. BMI increased significantly with increasing calendar year of diabetes identification in multivariable regression analysis. Analysis of survival revealed an increased hazard of mortality for BMI > or =41, relative to BMI of 23-25 (hazard ratio 1.60, 95% CI 1.09-2.34, P = 0.016). CONCLUSIONS: The prevalence of obesity and extreme obesity among individuals at the time they first met criteria for diabetes has increased over time. This is disturbing in light of the finding that diabetic individuals who are extremely obese are at increased risk of mortality compared with their nonobese diabetic counterparts.

Amorphous structures in the immiscible Ag-Ni system.

Vapor quenching in the phase-separating Ag-Ni system creates alloys that appear homogeneously amorphous under conventional probes. However, an atomic-level structural analysis based on extended x-ray absorption fine structures in combination with reverse Monte Carlo and molecular dynamics simulations demonstrates that these new phases are characterized by nonuniform, spinodal-like structures on an extremely fine scale. This heterogeneous nature of the structure is directly responsible for the unexpectedly low heat (and temperature) of crystallization observed in calorimetric measurements.

Radiation oncology practice accreditation.

The practice accreditation program of The American College of Radiology is described. Practice accreditation constitutes a facile mechanism to accomplish external quality assurance and to assess compliance with recognized standards. The process of accreditation includes critical review of each radiation therapy facility, the technical staff, all quality assurance procedures, medical physics staff, nursing and physician personnel as well as a whole host of other items, the most important of which is meticulous examination of selected patient charts. In the appendix, standards developed by the American College of Radiation Oncology, are reported.

PANORAMA: an integrated Web-based sequence analysis tool and its role in gene discovery.

As the exponential growth of DNA sequence information in databases continues, the task of converting this deposited information into knowledge becomes more dependent on integrative sequence analysis and visualization tools. PANORAMA is an Internet-accessible software package that performs a variety of informatics analyses on a given DNA sequence and returns a visual and interactive representation of the results. Its design is modular, so that further sequence analysis tools can be integrated with minimal effort. The utility of PANORAMA is demonstrated in the analysis of 650 kb of human genomic DNA from chromosome region 3p21.3, a region of potential tumor suppressor genes involved in lung cancer, breast cancer, and other forms of cancer. PANORAMA aided in the discovery of genes and alternate splice forms of known exons, in the demarcation of intron-exon boundaries, and in the identification of promoter regions and polymorphisms, all of which contributed to a better understanding of the region. PANORAMA is available on the World Wide Web at http://atlas.swmed.edu.

Results of the 1992 association of residents in radiation oncology (ARRO) survey.

In 1992 the Association of Residents in Radiation Oncology (ARRO) conducted its ninth annual survey of all residents in training. The survey identified perceived strengths and shortcomings of training. Factors influencing the choice of Radiation Oncology as a medical specialty were identified. Residents raised concerns over the adequacy and preparation of training. Factors influencing the decision to enter private practice or academic medicine were also identified. Future surveys are planned to expand this important database.

Novel tumor necrosis factor toxic effects. Pulmonary hemorrhage and severe hepatic dysfunction.

Recombinant human tumor necrosis factor is an investigational antitumor agent currently undergoing clinical trials. Previous reports of pulmonary and hepatic toxicities include mild reversible decline in pulmonary diffusing capacity and mild elevation of bilirubin and transaminases. This report describes two novel toxicities in patients receiving their first intravenous dose of tumor necrosis factor: pulmonary hemorrhage and severe hepatic dysfunction. These patients received no other antitumor therapy for at least 4 weeks before tumor necrosis factor treatment and no additional antitumor therapy concomitant with tumor necrosis factor. An analysis of the possible pathogenesis is presented.

Development of systemic lupus erythematosus after interferon therapy for chronic myelogenous leukemia.

A 19-year-old man with Philadelphia-positive chronic myelogenous leukemia treated with interferon-alpha (IFN-alpha) therapy for 45 months had systemic lupus erythematosus disease features: malar rash, migratory arthralgias, elevated antinuclear antibodies, elevated antinative DNA, hypocomplementemia, lymphopenia, and proteinuria. After discontinuation of the IFN and initiation of corticosteroids, there was gradual recovery of symptoms, a decline in antinative DNA and antinuclear antibodies to normal levels, and a decrease in proteinuria. The potential association between IFN therapy and the development of systemic lupus erythematosus, and the role of IFN in other autoimmune diseases, is discussed.

Supplementary feeding programs: a critical analysis.

A critical analysis of the Supplementary Feeding Programs which have been undertaken around the world is presented. Although only a few programs have been rigorously evaluated it seems that in relation to their main objectives, most of them have not proved to be successful. Some suggestions for improvement are put forward and the particular case of the Brazilian programs is assessed in detail.

Anthropometric measurements of white and black southern adolescent girls.

Anthropometric measurements of 691 white and 550 black 12-, 14-, and 16-year-old girls from three income groups, residing in the southern United States, were evaluated, Heights, weights, mid-upper arm circumferences, and arm muscle areas of 14-year-old girls were significantly higher than those of 12-year-old girls and significantly lower than those of girls 16 years of age; triceps skinfolds, arm fat areas, and body mass indexes of 12-year-olds were significantly lower than those of older subjects. Blacks had significantly higher weights, body mass indexes, and arm muscle areas than whites. Black 12-year-old girls were significantly taller than white 12-year-old girls but significantly shorter than older girls of either race; white 16-year-old girls were significantly taller than blacks of that age. Body mass indexes of black 12-year-olds and white 14-year-olds were significantly higher than those of white 12-year-olds, and significantly lower than those of black 14- and 16-year-olds. Medium-income blacks and whites of all income levels had lower (usually significantly) weights, body mass indexes, mid-upper arm circumferences, arm muscle areas, and arm fat areas than low- and high-income blacks did. Anthropometric values of white, but not of black, girls were generally similar to those reported in surveys of primarily white girls.

[Cardioactive contaminants and actual active ingredient content of various digitalis preparations]. / Kardioaktive Verunreinigungen und tatsächlicher Wirkstoffgehalt verschiedener Digitalispräparate.

To establish possible cardioactive impurities which have not been totally separated while isolating the compound from plant material several preparations containing digoxin (NOVODIGAL = beta-acetyldigoxin, LANITOP = beta-methyldigoxin and LANICOR = digoxin) were analyzed by HPLC-chromatography after careful extraction. Impurities were found (digoxigenin, digoxigenin-monodigitoxosid, digoxigenin-bisdigitoxosid) which on the one hand occur as natural lanatosid-derivates in digitalis leaves but on the other hand also are described as possible metabolites of digoxin in human organism. The experiments have shown that the results of studies in metabolization of digoxin without knowledge of purity of the substance applied have to be interpreted with care.

Erythrocyte and dietary zinc in adolescent females.

Erythrocyte zinc has been suggested as an index of zinc status. This study was undertaken to investigate the possible relationships of erythrocyte zinc concentration to age, physical maturity, and zinc intake of teenage girls of two races. Dietary zinc was calculated from two 1-day food recalls, and erythrocyte zinc was determined for over three hundred 12-, 14- and 16-yr-old girls in Oklahoma and Virginia. Erythrocyte zinc concentration increased and the intake of zinc from the diet decreased after attainment of menarche. Among girls of the same menarcheal state, age was not related to zinc intake, but concentration of zinc in erythrocytes increased with each 2-yr age increment in those that were past menarche. Results did not show a direct relationship of erythrocyte zinc values to calculated intakes of zinc by adolescent females. Black and white races did not differ in either zinc intake or red cell zinc content.

Temas seleccionados sobre medicina de animales de laboratorio: el cobayo

[Prefacio] Este es el tercer trabajo de una serie de monografías sobre animales de laboratorio editado por la Organización Panamericana de la Salud (OPS), Centro Panamericano de Fiebre Aftosa(CPFA). El contenido de referencia, impreso antes de 1976 fue extraído en su mayor parte de THE BIOLOGY OF THE GUINEA PIG (Biología del Cobayo), trabajo publicado por Joseph E. Wagner y Patrick J. Manning y patrocinado por el "American College of Laboratory Animal Medicine" (Colegio Americano de Medicina de Animales de Laboratorio). El contenido que aparece en esta publicación es objeto de referencias individualizadas. El propósito de este trabajo es presentar de manera concisa mucho del conocimiento publicado y de la experiencia personal acerca de la biología básica y de la producción y manejo de cobayos en las regiones tropicales y subtropicales.