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Biomedical subjects

K Young

Publications and source records attributed to K Young.

189 records · Page 11Linked to original sources
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Analytic calculation of electron beam isodose distributions.

Analytical techniques have been developed to generate electron beam isodose distributions from a modest set of experimental data. These techniques include (1) development of a compact yet powerful linear least-squares optimization program with a graphic display of the results, (2) coordinate transformations to allow straightforward fitting of the isodose distributions with simple polynomial functions, and (3) accurate interpolation methods to allow production of treatment planning dose matrices. The program, written in FORTRAN, has been implemented on a minicomputer and uses the standard peripherals of a commercially available treatment planning system (AECL TP-11). The computer-generated isodose and central-axis distributions correspond very closely with the data for electron energies from 5 to 20 MeV and for all field sizes.

Electrons↗
PubMedDate not supplied

Determination and survey of ochratoxin A in wheat, barley, and coffee--1997.

Ochratoxin A (OA) is a nephrotoxic and nephrocarcinogenic mycotoxin produced by Aspergillus and Penicillium species. It has been found mainly in cereal grains and coffee beans. The purpose of this study was to investigate the occurrence of OA in cereal grains and in coffee imported to the United States. A modified liquid chromatographic (LC) method for determining OA in green coffee was applied to wheat, barley, green coffee, and roasted coffee. The test sample was extracted with methanol-1% NaHCO3 (7 + 3), and the extract was filtered. The filtrate was diluted with phosphate-buffered saline (PBS), filtered, and passed through an immunoaffinity column. After the column was washed with PBS and then with water, OA was eluted with methanol. The eluate was evaporated to dryness, and the residue was dissolved in acetonitrile-water (1 + 1). OA was separated on a reversed-phase C18 LC column with acetonitrile-water-acetic acid (55 + 45 + 1) as eluant and quantitated with a fluorescence detector. Recoveries of OA from the 4 commodities spiked over the range 1-4 ng/g were 71-96%. The limit of detection was about 0.03 ng/g. OA contamination at > 0.03 ng/g was found in 56 of 383 wheat samples, 11 of 103 barley samples, 9 of 19 green coffee samples, and 9 of 13 roasted coffee samples. None of the coffee samples contained OA at > 5 ng/g; only 4 samples of wheat and 1 sample of barley were contaminated above this level.

Carcinogens↗
PubMedDate not supplied

Cervical pathology in West Virginia adolescents.

Cytologic screening is an important diagnostic tool used to detect precancerous and cancerous lesions of the cervix. We studied the prevalence of cervical abnormalities, based on Pap smear results, in patients at the Outpatient Adolescent Clinic at West Virginia University. We found a high incidence of overall intraepithelial cell pathology (24%) in this group with 2.4% high grade and 9.9% low-grade lesions. These findings show that major cervical pathology is present in this age group. Furthermore, repeat smears at intervals of < one year were performed on 317 patients. Of these repeat smears, 7% changed from normal to abnormal in this period. Sexually active adolescent females should have Pap smears at least annually to detect abnormalities that may otherwise not be detected until they are more advanced and difficult to manage. Higher risk adolescents may need semiannual screening.

Adolescent↗
PubMedDate not supplied

Comparison of two immunochemical methods with thin-layer chromatographic methods for determination of aflatoxins.

Three different methods were compared for the determination of total flatoxins in corn and peanuts naturally contaminated with aflatoxins and in corn, peanuts, cottonseed, peanut butter, and poultry feed spiked with aflatoxins B1, B2, and G1. The 3 methods were an enzyme-linked immunosorbent assay (ELISA) screening test; a monoclonal antibody-affinity column-solid-phase separation method; and the AOAC official thin-layer chromatography (TLC) methods for all except poultry feed, for which Shannon's TLC method for mixed feed was used. The ELISA test is designed to provide only positive results for total aflatoxins at greater than or equal to 20 ng/g or negative results at less than 20 ng/g. The affinity column separation is coupled with either bromination solution fluorometry to estimate total aflatoxins or liquid chromatography (LC) to quantitate individual aflatoxins. Fluorodensitometry was used to determine aflatoxins in commodities analyzed by the TLC methods. The LC and TLC results were in good agreement for all the analyses. The results for the affinity column using bromination solution fluorometry were similar except those for cottonseed, which were about 60% higher. The ELISA screening method correctly identified naturally contaminated corn and peanut positive samples. No false positives were found for controls. The correct response for spiked corn, raw peanuts, peanut butter, and cottonseed at greater than or equal to 20 ng aflatoxins/g was about 90%. The correct response for spiked poultry feed at greater than or equal to 20 ng aflatoxins/g was about 50%.

Aflatoxins↗
PubMedDate not supplied

Cyclopiazonic acid production by cultures of Aspergillus and Penicillium species isolated from dried beans, corn meal, macaroni, and pecans.

Ninety-five isolates of Aspergillus and Penicillium species from selected dried foods were examined for their ability to produce cyclopiazonic acid (CPA). The isolates were grown in sterile synthetic liquid medium at 28 degrees C for 8 days in the dark. The medium and mold mycelia were then extracted with chloroform. CPA was semiquantitatively determined by thin layer chromatography through visual comparison with standards. The cultures of A. flavus were also examined for their ability to produce aflatoxin. One A. tamarii and all 13 P. urticae isolates produced CPA, whereas only 19 of the 31 (61%) A. flavus isolates produced CPA, and 6 (19%) A. flavus produced aflatoxin. All 13 P. urticae isolates also produced patulin and griseofulvin. CPA-producing A. flavus was found in all food types but not in all samples. CPA-producing P. urticae was found only in dried beans and macaroni.

Aflatoxins↗
PubMedDate not supplied

Survey of deoxynivalenol in U.S. 1993 wheat and barley crops by enzyme-linked immunosorbent assay.

Wheat and barley from the 1993 crop year were analyzed for deoxynivalenol (DON). A total of 630 samples were collected by the Federal Grain Inspection Service in 25 states and analyzed using a commercially available, direct competitive, enzyme-linked immunosorbent assay. The limit of determination was about 0.5 micrograms/g. DON contamination in the 483 wheat samples averaged 2.0 micrograms/g and ranged from < 0.5 to 18 micrograms/g. DON contamination in the 147 barley samples averaged 4.2 micrograms/g and ranged from < 0.5 to 26 micrograms/g. About 40% fo the wheat samples and 57% of the barley samples contained DON levels that were greater than the U.S. Food and Drug Administration 1982 advisory level of 2 micrograms/g for DON in wheat designated for milling (human consumption).

Enzyme-Linked Immunosorbent Assay↗
PubMedDate not supplied

Quality of life of adult long-term survivors of bone marrow transplantation: a qualitative analysis of narrative data.

Recently, clinicians and researchers alike have challenged the long-standing impression that survivors of bone marrow transplantation (BMT) experience a less than optimal quality of life (QOL). Despite the accumulating evidence suggesting that most adult survivors adjust relatively well within two to five years after BMT, little is known about the growing population of recipients living well beyond five years. This paper reports the design and qualitative components of a large study that used a cross-sectional, descriptive, mailed survey design. The aim of the study was to document systematically how 125 adult survivors of BMT (6-18.4 years post-transplant) perceived the quality of their lives. An eight-item, open-ended questionnaire was used to gather information on the reestablishment of life after BMT, demands of recovery, coping strategies, limitations imposed by BMT, current health problems, QOL, and concerns for the future. Content analysis of the verbatim responses indicated that most long-term survivors, despite the persistence of lingering side effects, perceive themselves as cured and well, leading full and meaningful lives. Nursing therapeutics can focus on providing accurate and timely information about the known long-range complications of BMT. Further research is needed to examine the entire issue of social support following BMT and to identify the special care requirements of the recipients (5%) who reported poor physical and mental health.

Activities of Daily Living↗