Subclinical effects

Effect. Potential biomarkers of the subclinical effects of hydrogen sulfide are decreases in the activities of the heme synthesis enzymes, ALA-S and Haem-S (Jappinen and Tenhunen 1990). These effects have nothing to do with the mechanism of toxicity, however. Neurological indices are also used as biomarkers of effect for hydrogen sulfide (Gaitonde et al. 1987 Kilbum 1993 Stine et al. 1976 Tvedt et al. 1991b). 

Baloh RW, Spivey GH, Brown CP, et al. 1979. Subclinical effects of chronic increased lead absorption—a prospective study 11. Results of baseline neurologic testing. J Occup Med 21 490-496. 

Milbum H, Mitran E. Crockford GW. 1976. An investigation of lead workers for subclinical effects of lead using three performance tests. Ann Occup Hyg 19 239-249. 

What are these subclinical effects Very simply, they are effects that occur at blood lead levels below those that produce clinically measurable effects - they occur in the absence of any sign of overt lead poisoning. These effects can be detected only by studying various forms of behavior, such as degree of hyperactivity and classroom attention span, and performance on various tests of intelligence and mental development. Deficits in neurobehavioral development, as measured by two widely used tests - the Bayley and McCarthy Scales - have been reported in children exposed prenatally (via maternal blood) to blood... 

Hathaway J A Subclinical effects of trinitrotoluene A review of epidemiology studies. In Richert DE (ed) Toxicity of Nitroaromatic Compounds, pp 255-274. New York, Hemisphere Publishing, 1985... 

Subclinical effects are often observed when molybdenum levels in soil exceed 3 pg/g an excess of molybdenum in forage is toxic to livestock. Deficiency diseases have been observed in livestock when soil molybdenum levels are below 0.5 pg/g. 

TCDD exposure, but biochemical examinations revealed a pattern suggestive of a subclinical effect on lipid metabolism (USAF 1991). Blood triglycerides showed a strong positive association with both the initial levels of 2,3,7,8-TCDD and the current serum levels the authors indicated that this variable is highly sensitive to body fat, which was increased in the more highly exposed individuals. Cholesterol, HDL, and the cholesterol-HDL ratio also showed significant associations with 2,3,7,8-TCDD. 

TCDD serum levels (USAF 1991). The diabetes finding remained significant even after adjusting for body fat. Furthermore, subclinical effects in thyroid function (significant decrease in mean T3 uptake and increases in mean TSH) were reported for Operation Ranch Hand veterans with high current... 

TCDD in these children. The findings from the Tognoni and Bonaccorsi (1982) study suggest that chloracne is a more sensitive toxicological endpoint than immunological effects because alteration in complement levels is a subclinical effect and correlated with the incidence of chloracne. 

Hsieh GC, Parker RDR, Sharma RP, et al. 1990. Subclinical effects of groundwater contaminants. III. Effects of repeated oral exposure to combinations of benzene and toluene on immunologic responses in mice. Arch Toxicol 64(4) 320-328. 

Hsieh GC, Sharma RP, Parker RDR. 1988b. Subclinical effects of groundwater contaminants I. Alteration of humoral and cellular immunity by benzene in CD-I mice. Arch Environ Contain Toxicol 17 151-158. 

The authors of a study of the use of MRI scans to assess the subclinical effects of the anthracyclines concluded that increased MRI enhancement equal to or greater than 5 on day 3 compared with the baseline predicted significant reduction in ejection fraction at day 28 (32). In 1000 patients given doxorubicin chemotherapy and irradiation there were six cases of congestive heart failure and three cases of myocardial infarction there was a cumulative cardiac mortality of 0.4% in all anthracycUne-exposed patients (33). 

Lamm O, Pratt H. 1985. Subclinical effects of exposure to inorganic mercury revealed by somatosensory-evoked potentials. Eur Neurol 24 237-243. 

When zinc deficiency is not severe enough to cause clinical signs and symptoms, it may still have a subclinical effect on immune function, the synthesis and action of hormones, and neurological function. 

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