Biomedical subjects

A Wu

Publications and source records attributed to A Wu.

At least 217 records · Page 12Linked to original sources

PubMed1976

Use of breath analysis to monitor methylene chloride exposure.

Twenty male and female subjects were exposed repetitively to methylene chloride (CH2Cl2) vapor, 50, 100, 250, and 500 ppm, for 1,3, or 7.5 h in a controlled-environment chamber. Postexposure alveolar breath samples were collected in small glass breath tubes and analyzed for CH2Cl2 by gas chromatography. From these data is a series of breath CH2Cl2 excretion curves were constructed that can be used to estimate the magnitude of a recent exposure. The CH2CL2 breath concentration in the immediate postexposure period accurately reflected the vapor concentration to which the subjects had been exposed most recently. Breath samples collected 1--2 h following exposure were accurate indicators of the time-weighted average vapor exposure experienced by the subjects during the previous 8 h of occupational exposure. Breath analysis offers a practical, noninvasive method for monitoring occupational exposure to CH2Cl2.

Adult↗

PubMed1976

Elevated serum gamma-glutamyl-transferase (transpeptidase) and histological liver damage in alcoholism.

In 66 alcoholic patients, serum gamma-glutamyl-transferase (transpeptidase) (GGTP) activity was studied in relationship to other biochemical liver function tests and histological liver damage. Elevated serum GGTP activity was the single most common biochemical abnormality (74%) and, when present was accompanied by histological abnormalities in all but one case. In seven patients, including two with alcoholic cirrhosis, this was the only biochemical abnormality. The mean serum GGTP was highest in the cirrhotic group. There was some correlation between serum GGTP activity and the degree of histological hepato-cellular necrosis. The values showed a wide scatter, however, and 12 patients had normal serum GGTP activity when histological damage was present. While elevated serum GGTP levels in alcoholism may be partly related to structural liver damage, other mechanisms, such as hepatic microsomal enzyme induction or alcoholic pancreatic damage, may also play a role.

Adult↗

PubMed1975

Folate deficiency in the alcoholic--its relationship to clinical and haematological abnormalities, liver disease and folate stores.

Clinical and laboratory observations were made on 84 patients regularly taking more than 80 g of alcohol daily. Macrocytosis was present in 84.5%, but only 13% were anaemic. Twenty-seven of the 57 bone marrows sampled were abnormal, 20 showing megaloblastic changes, mostly mild in degree. Serum, red cell, and liver folate levels were reduced in 28%, 35% and 31% of patients respectively. Liver folate concentration showed good correlation with serum and red cell folates. The folate deficiency was more severe in those patients, more often female, who had inadequate diets or drank wine and spirits rather than beer. The amount of alcohol consumption and extent of liver damage did not affect folate status. The findings suggest that folate deficiency is common among alcoholics in this country. More frequently, however, patients had macrocytosis, sometimes with megaloblastosis, in the absence of folate deficiency emphasizing the direct toxic effect of alcohol on the developing erythroblast.

Adult↗

PubMed1975

Rapid analysis of the central nervous system stimulants, amphetamines, via gas chromatography-mass spectrometry: rapid acylation in the presence of a mercury catalyst.

A simple, direct, instantaneous, and quantitative acetylating procedure for amphetamines has been developed. The method uses trifluoroacetic anhydride in the presence of mercuric trifluoroacetate as a catalyst. The product was characterized by a gas chromatography-mass spectrometry system. The salient features of this technique are: (a) rapidity of analysis; (b) no previous cleanup to remove adulterants; and (c) detection of amphetamines at the picomole level. We have routinely applied this technique for court samples and law enforcement authorities. The method could prove to be applicable, with minimum amounts of involvement in sample preparation, to the analysis of a variety of compounds containing an acyl displaceable hydrogen.

Acylation↗

PubMed1975

Effect of alcohol on total urinary hydroxyproline excretion.

Urinary hydroxyproline excretion was measured in 33 patients regularly drinking over 80 gm. alcohol daily. Those with changes of cirrhosis on liver biopsy excreted significantly more hydroxyproline than those with normal appearances, fatty change or hepatofibrosis. In 16 patients, the excretion was measured both when they were drinking and when abstaining from alcohol, in the form of several beverages. The rate of excretion was significantly higher after alcohol has been withdrawn. This result raises the possibility that alcoholic beverages may inhibit collagen degradation. If substantiated, it further suggests that the effect of alcohol on collagen metabolism may be of importance in the pathogenesis of alcoholic cirrhosis.

Alcoholism↗

PubMed1974