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Biomedical subjects

H K Wilson

Publications and source records attributed to H K Wilson.

65 records · Page 4Linked to original sources
PubMed1976

Food intake, dietary supplements and survival time of scorbutic guinea pigs.

Manual presentation of a liquid scorbutogenic diet permitted a more complete characterisation of the terminal stages of scurvy in guinea pigs. A bioflavonoid preparation from orange peel, previously shown both to increase the tissue concentrations of ascorbic acid and to stimulate the growth of hypovitaminotic C guinea pigs, had no influence on the survival time of scorbutic guinea pigs. Tetrahydrofolic acid, reported to possess 40% of the activity of ascorbic acid in the protocollagen proline-hydroxylase system, also failed significantly to prolong the survival period. This latter finding could indicate that ascorbic acid has essential biochemical functions in addition to its involvement in the hydroxylation of proline and lysine.

Animals↗
PubMedDate not supplied

A GC/MS method for the determination of 4,4'-diaminodiphenylmethane and substituted analogues in urine.

A sensitive and specific gas chromatography/mass spectrometry (GC/MS) method has been developed for the analysis of 4,4'-diaminodiphenylmethane (DDM), 3-ethyl DDM (EDDM), and 3,3'-diethyl DDM (DEDDM) in urine. The method has been applied to the analysis of urine samples from workers exposed to a mixture of all three compounds, and the analysis has shown that EDDM and DEDDM are excreted in urine. We have also shown that there are two classes of conjugates present in urine. EDDM and DEDDM are excreted as heat labile conjugates, while DDM and EDDM are excreted, at least in part, as heat stable but alkaline hydrolyzable conjugates. It is proposed that the method described here could be used for biological monitoring of workers exposed to mixtures of DDM, EDDM, and DEDDM.

Aniline Compounds↗
PubMedDate not supplied

Sample handling and storage for the quantitative analysis of volatile compounds in blood: the determination of toluene by headspace gas chromatography.

The problems associated with the handling and storage of blood samples for the analysis of toluene in toxicological casework using headspace gas chromatography have been investigated. Significant losses of toluene and the internal standard, ethylbenzene, from solution may be observed during handling. Toluene may be lost into the headspace above the blood in a storage container while such headspaces can also be detrimental, leading to the formation of n-hexanal, a possible interference with the assay. Large differences in the stability of toluene were seen for blood samples in different types of storage container. Storage containers in which the sample was only in contact with glass, teflon, or aluminum foil were most satisfactory. It is recommended that blood samples should be stored in appropriate containers with minimum headspace under cold conditions (4 degrees C). Transfers of blood should also be made at cold temperatures. The applicability of these guidelines to the analysis of other volatile compounds is discussed.

Blood Preservation↗
PubMedDate not supplied

The determination of 4,4'-methylenebis (2-chloroaniline) in urine by electron capture gas chromatography.

The development and use of a gas chromatographic method for monitoring workers who are occupationally exposed to 4,4'-methylenebis(2-chloroaniline) (MBOCA) is reported. The increase in ether-extractable MBOCA on mild hydrolysis is determined. The analytical conditions for a specific and sensitive electron capture gas chromatographic method that will measure both "free" MBOCA and "total" MBOCA are established. It is suggested that workers should be monitored by the measurement of "total" urinary MBOCA.

Benzhydryl Compounds↗
PubMedDate not supplied

The measurement of salivary cadmium by electrothermal atomic absorption spectrophotometry and its use as a biological indicator of occupational exposure.

We have examined the potential use of salivary cadmium measurements for the biological monitoring of occupational cadmium exposure, paying particular attention to the contamination risks associated with such measurements. We have developed a method for the direct determination of cadmium in saliva by graphite furnace atomic absorption spectrophotometry, which minimizes the risk of contamination during sample preparation and analysis. The limit of detection is 0.6 nmoll-1, which is sufficiently sensitive to discriminate between unexposed and occupationally exposed individuals. The method has been employed to measure cadmium levels in saliva samples collected by two different methods from an unexposed population, a group of ex-workers previously exposed to cadmium (Group 1), and two groups of currently exposed workers (Groups 2 and 3). Salivary cadmium levels were significantly raised in both of the groups of currently exposed individuals (group 2 median (Md) = 17 nmoll-1, group 3 Md = 70 nmoll-1, p greater than 0.0001), and in past workers with previous long-term exposure (Group 1 Md = 2.5 nmoll-1, p greater than 0.001) when compared with an unexposed population. The results suggest that the measurement of salivary cadmium may reflect recent exposure to the metal. However, considerable care must be taken in collecting samples because a risk of contamination during sampling is apparent with procedures commonly used for saliva collection, and for this reason the applicability of such measurements for biological monitoring is limited.

Cadmium↗