Dosimetry measurements and analyses of 10-MV x rays for Clinac-18

Radiation parameters for two Varian Clinac-18 10-MV x-ray units were measured and compared with the same parameters for the Toshiba LMR-13 and the Arco Mevatron XII. Comparison of the percentage depth dose, surface dose, and depth of maximum ionization as a function of field size are presented.

Carboxyhemoglobin trend in Chicago blood donors, 1970-1974

An 18% reduction in the carboxyhemoglobin (HbCO) saturation in nonsmoking Chicago blood donors occurred between 1970 and 1974, indicating that current donors are being exposed to a lower average carbon monoxide (CO) concentration than had been experienced by 1970 donors. In contrast to the situation in 1970, when it was discovered that 74% of the nonsmokers in Chicago were being exposed to CO in excess of the amount permitted by the federal air quality standards, in 1974 only 41% of the nonsmokers were being overexposed. The observed reduction in HbCO correlates well with both the ambient CO levels recorded at the air monitoring stations and the reduction in CO emission from automobiles. If the current trend continues, Chicago should reach compliance with air quality standards for CO by 1985. The measurement of HbCO in a representative urban population is an accurate index of actual CO exposure and supplements the air pollution data provided by air monitoring stations.

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.

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.

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.

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.

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.

Reduced serum somatomedin activity in patients with chronic liver disease

1. Somatomedin (SM; sulphation factor) activity was estimated by a chick-cartilage assay in fasting sera from twenty-one patients with chronic liver disease.

2. Low SM values were found in nine out of the ten patients with cirrhosis and in two other patients, one with hepatofibrosis and one with hepatoma.

3. In general, the lowest serum SM activities were found in those patients with the most severe disease and significant correlations were found between serum SM and serum albumin, alkaline phosphatase and bilirubin.

4. Growth hormone was also measured in the samples and concentrations above 10 units/ml were found in seven patients, all of whom had reduced serum SM activities.

5. These findings indicate that low serum SM activity in liver disease is not related to growth hormone deficiency and suggest that the liver may be an important site for SM synthesis in man.