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Biomedical subjects

L C Taylor

Publications and source records attributed to L C Taylor.

29 records · Page 2Linked to original sources

Properties of aflatoxin-DNA adducts formed by photoactivation and characterization of the major photoadduct as aflatoxin-N7-guanine.

Aflatoxin-DNA adducts were formed by microsomal and photoactivation, using nick-translated DNA labelled with 14C in each of the DNA bases [3H]AFB1 and [3H]AFB2. DNA adducts were analysed by HPLC of DNA hydrolysates, and were characterized as double labelled peaks with specific retention times. The only AF-DNA adducts which were detected in significant amounts were guanine adducts, irrespective of the type of aflatoxin used or the mode of its activation. No stable adduct with adenine, cytosine or thymine was detected. UV spectra, proton NMR spectroscopy and mass spectrometry are consistent with the notion that the major AFB1-DNA photoadduct is the N7-guanine adduct. This report provides direct evidence for the existence of aflatoxin photoadducts formed on DNA.

Aflatoxin B1↗

Expectations and outcome skills of a generalist health care administrator.

The question of the degree of technical versus managerial competence to be found in future graduates from health administration programs is not easily resolved. In the HIMSS 1988 survey of CIOs the attributes needed for success are listed in descending rank order as follows: leadership ability, vision/imagination, knowledge of hospital systems, business acumen, decisiveness, and technical competence. CIOs ranked technical competence as less important than other attributes associated with general management success. The expectations for attitudes, knowledge, and skills presented in this article support the greater importance of management abilities relative to pure technical competence. However, it is vital that an appropriate level of technical knowledge and skill be maintained to enable future alumni of health administration programs to function effectively as administrators. Depending on their role in a health care organization, greater or lesser technical knowledge may be needed. Those pursuing a career path toward CIO must, of necessity, have greater technical knowledge and skill. We have discussed necessary and expected attitudes, knowledge, and skills that will be needed by the generalist health administration graduate in the future. It will be important to develop and maintain an attitude that MIS is a strategic tool, that health care technology is a corporate asset, and that information is power. Graduates must recognize the necessity of maintaining and enhancing their knowledge and skills through continuing education. The knowledge base of MIS education should focus on determining information needs to support strategic goals, understanding of general systems theory, principles of systems analysis, design, implementation and maintenance, awareness and exposure to standard application software, and an awareness of external sources of data.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Literacy↗

Improved detection limits in an organic mass spectrometer using a combination of matrix free FAB and photodiode array detection.

Scanning mass spectrometers suffer from the disadvantage of monitoring only one mass at any particular time in contrast to mass spectrographs which allow the simultaneous detection of an extended mass range. Historically such mass spectra were recorded by directing the ion beam onto a photographic plate which was subsequently developed and interpreted. The introduction of electronic devices such as the photodiode array enabled the development of imaging detectors capable of real time readout, so that a range of masses can be detected and rapidly processed using a computer system. This work uses such a detector in combination with a double focusing MS50RF mass spectrometer for the parallel detection of a limited mass range.

Mass Spectrometry↗

Alloviroidin, the naturally occurring toxic isomer of the cyclopeptide viroidin.

A novel toxic cyclopeptide from Amanita suballiacea (Murr.) mushrooms that possesses structural features similar to viroidin is described. This peptide, alloviroidin, is identical with viroidin in mass, affinity for actin, and all amino acids except for one. The single discernible difference between the two peptides exists in the configuration at carbon 4 of the 4,5-dihydroxyleucine residues, as shown by a combination of chemical modification and magnetic resonance experiments. The configuration of this residue in viroidin is similar to that of phalloidin and is 2S,4R, while that in alloviroidin is established to be 2S,4S. This peptide is thus unique in its hydroxylation pattern among both the virotoxins and phallotoxins and may be an intermediate for more highly hydroxylated virotoxins, such as viroisin.

Actins↗

The bowel habit of milk-fed infants.

A prospective study of the bowel habits of 240 infants aged 2-20 weeks was performed. Half of the infants were breast fed and half were fed cow's milk formula (CMF). Breast-fed infants had a higher mean frequency of defaecation than did CMF-fed infants at 2, 4 and 8 weeks (p less than 0.02). By 16 weeks the mean frequency of bowel actions per day of infants of both feeding groups was 2. With increasing age, infants produced fewer stools of greater firmness (p less than 0.05) though the breast fed tended to pass larger, softer stools than did the CMF-fed infants until the introduction of weaning foods (p less than 0.05). Stool colour was uniformly yellow in both feeding groups until the introduction of weaning foods, when it changed to brown. Weaning foods were introduced at an earlier age in the CMF-fed infants (p less than 0.05), though by 20 weeks 93% of all infants had received some. These data define the normal range of the bowel habits of milk-fed infants and may reflect differences in gastrointestinal function between those fed on the breast and with CMF.

Animals↗

Disposition, metabolism, and excretion of the anticancer agent crisnatol in the rat.

Disposition and metabolism of crisnatol (14C-labeled), a novel antitumor agent, was examined after po and iv administration to rats. After both routes of drug administration, there was rapid elimination of the administered radioactivity in the urine (6-12% of the dose) and feces (81-92% of the dose). The drug appeared to be rapidly absorbed after oral dose and there was substantial "first-pass" metabolism. Analysis of the excreta indicated extensive metabolism of crisnatol by the rat, with the intact compound being the major radiolabeled component in the feces (17-20% of dose). Intact drug was not present in urine. Biotransformation of crisnatol by the rat mainly involves oxidation and conjugation pathways. Hydroxylation and dihydrodiol formation in the chrysene ring and oxidation of the propanediol side chain resulted in the formation of the three major fecal metabolites. The principal metabolite in the urine was also a dihydrodiol. Concentrations of intact drug in each tissue assayed exceeded those in plasma, and in the lungs the tissue/plasma ratio approached 300 and 82 at 2 hr after iv and po doses, respectively.

Animals↗