Silica exposure and serum angiotensin converting enzyme activity.

BACKGROUND: Silicosis is known in industrial workers for centuries. Till recently, the mainstay of its diagnosis and progress was clinical examination of the respiratory system, pulmonary function test and chest radiography. Several biomarkers such as serum angiotensin converting enzyme (ACE) activity have been examined to determine the extent of silicosis. OBJECTIVE: To elucidate the effect of age, gender, duration of exposure to silica dust, smoking habit, and pulmonary function status on the serum ACE activity among quartz stone workers without disease. METHODS: A cross-sectional study was carried out on 134 (111 men and 14 women) workers of quartz stone crushing units were studied. Standard diagnostic criteria were used for diagnosing silicosis and tuberculosis. Pulmonary functions of the participants were also assessed. RESULTS: The mean±SD age for participants was 26.1±6.3 years (26.6±6.3 for men and 21.9±4.3 for women). The mean±SD duration of exposure was 1.1±1.9 years. In the present study, only one case of silicosis and eight cases of tuberculosis were found. The mean±SD serum ACE levels for those with and without respiratory disease were 68.44±11.61, and 66.9±14.4 IU/L, respectively (p>0.05). CONCLUSION: We could not observe any association between serum ACE activity and age, gender, duration of exposure, smoking habits and pulmonary function status. However, elevated levels of serum ACE was found in a solitary case of silicosis.

Erosion of nails following thallium poisoning: a case report.

This case report describes a patient with thallium poisoning caused by repeated exposure to low doses of thallium. Alopecia and nail changes were the most prominent features of this case. There was dystrophy of nails in the form of whitish lunular stripes. This is the first report of complete erosion of proximal parts of nails following thallium poisoning. This case is the first report of thallium poisoning from India occurring from repeated low dose exposure.

Humoral immunological profile of workers exposed to asbestos in asbestos mines.

Humoral immunological profile including immunoglobulins IgG, IgA, IgM, C-reactive protein, rheumatoid factor, antinuclear antibodies and circulating immune complexes were studied in a representative sample of 36 workers suffering from asbestosis (group A), 35 workers who are exposed to asbestos but not having evidence of asbestosis (group B) and 28 control workers (group C). Mean IgG and IgA levels were found to be significantly higher in the two exposed groups than in the controls. Circulating immune complexes of IgG, IgA and IgM class were detected in a significant percentage of cases in exposed groups than in controls. In groups A and B, the percentage of positive ANF cases was much higher than in the controls. The results suggest that immunological changes are associated with exposure to asbestos and these may play an important role in the pathogenesis of the disease process.

Clinical and biochemical investigations to evolve early diagnosis in workers involved in the manufacture of hexachlorocyclohexane.

365 individuals exposed to hexachlorocyclohexane (HCH) during its manufacture were studied and compared with 146 controls. These 502 cases were divided into five groups on the basis of serum total HCH levels. Exposure was mainly through skin. Results indicate that neurological symptoms reported were due to recent exposure to HCH and were related to the intensity of exposure. ECG abnormalities were seen in exposed cases. A significant positive correlation to liver related enzymes gamma GT, LAP and Alp. P was observed. beta-globulins significantly increased along with an increase in total HCH. Changes in IgM levels were similar as observed in IgA. Remarkably high concentration of HCH residues were found in the serum samples of all exposed workers. beta-HCH contributed more than 80% of the total HCH built up. Presence of circulating immune complexes was also detected in representative samples. Further, repeated biological monitoring was advised to be carried out among such workers exposed to HCH, to evaluate signs of severe health impairment in them.

Humoral immunologic dysfunction in silicosis.

Immunoglobulins may play an important role in the evolution of silicosis, and their determination may serve as a helpful criterion in the diagnosis of silicosis. Serum immunoglobulin levels were studied in slate pencil workers (130) exposed to high concentrations of silica dusts and non-exposed controls (50). Significantly higher levels of immunoglobulins were observed in the silica exposed individuals. A rising trend in the serum IgG from a mean of 1373 mg/dl in control group to 2193.68 mg/dl in exposed group (conglomerate) and IgM from 140.51 mg/dl in control to 201.19 mg/dl in exposed group (conglomerate silicosis) was observed with increase in the duration of dust exposure. Highest mean levels of IgG (2193.60 mg/dl) and IgM (201.19 mg/dl) were observed in the workers having conglomerate silicosis. The results indicate that though, the levels of immunoglobulins were raised in subjects exposed to silica, this parameter may be of limited value for determining progressive of silicosis.

Serum hexachlorocyclohexane residues in workers engaged at a HCH manufacturing plant.

The accumulation of hexachlorocyclohexane, one of the most commonly used chlorinated insecticides, was studied in a high-risk group of people who are exposed during its manufacturing process. The serum HCH concentration was estimated by quantitating its alpha, beta, gamma and delta-isomers with the help of GLC analysis. Exposed workers involved in maintenance work were found to have 3 times higher HCH residues than the controls, while in the plant operators and supervisors the levels were 5 times higher. The most severely exposed were the handlers who are in direct contact with the insecticide. The level of serum HCH residues in them was found to be about 12 times higher than those in the controls. The percentage composition of the insecticide, with respect to the different isomers, varied up to 20% for the gamma-isomer, up to 30% for alpha-isomer and had between 60%-100% of the beta-isomer in the samples. The serum levels of the insecticides were clearly related to the workers' job-related close contact, intensity, frequency, and the duration of their exposure. The total of HCH residues in the sera studied were in the range of 0.143-1.152 ppm. The importance of these findings and the relevant protective measures are discussed.

Dominant-lethal study of technical-grade hexachlorocyclohexane in Swiss mice.

Male Swiss mice, 6-8 weeks old, were given a diet containing technical-grade hexachlorocyclohexane (BHC) at 500 ppm continuously for 4, 6 and 8 months. After the completion of the scheduled exposure period, the males were sequentially mated with 2-3 untreated virgin females at weekly intervals for 8 weeks. The females were autopsied at mid-term pregnancy for evaluation of dominant-lethal mutation. The number of dead implants, including deciduomas and dead embryos, showed a significant increase. Similarly, the percentage fertility and live embryos per female showed a decline when compared with the control

Distribution of isomers of BHC and related histopathology of liver in hexachlorocyclohexane (technical grade BHC) fed mice.

In an attempt to correlate body burden and related liver histopathology after exposure to 500 ppm benzene hexachloride, 6- to 8-wk-old male and female mice were fed benzene hexachloride with their mash diet for a 6-month period. The mice were divided into 8 groups (12/group; 6 experimental, 6 control) and were sacrificed by group monthly. During the first month, 3 groups of mice were sacrificed after 10, 20, and 30 days of treatment, respectively. A dose-related increase in liver weight was found in test animals (P less than .01). The histopathology of liver showed clear, oval cells; hypertrophied cells with foci; and neoplastic nodules that were apparent during the final 3- to 6-month period. Few oval and hypertrophied cells were found in control animals. The alpha isomer concentration of benzene hexachloride rose during the first 2 months of treatment, but declined after that time. A transient rise was noted for the beta isomer concentration of benzene hexachloride at the end of the 6-month period. The gamma isomer concentration was elevated during the initial 3 months of treatment, but declined during the subsequent 3 months. The results present definitive changes suggestive of precancerous states.

Early changes in serum protein and liver LDH isoenzymes in mice exposed to technical grade hexachlorocyclohexane (BHC) and their possible relationship to liver tumours.

Mice were exposed to hexachlorocyclohexane (BHC) in order to study the changes in the serum protein pattern and in the LDH isoenzymes of the liver. After 2 months of exposure the protein pattern showed a new band which persisted even after the development of a tumour. The LDH isoenzymes pattern showed a gradual decrease of the faster moving LDH-1 and LDH-2 bands which later disappeared completely when hepatic tumours formed. The significance of these results is discussed.