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Biomedical subjects

J A Valciukas

Publications and source records attributed to J A Valciukas.

At least 19 recordsLinked to original sources
PubMed1990

Fall-off in reporting life events: effects of life change, desirability, and anticipation.

The influence of event characteristics on recall was examined by directly comparing fall-off in reporting life events as a function of life change, desirability, and anticipation. We collected information from a sample of 1,669 blue-collar workers on stressful life events that occurred in a 1-year interval before the questionnaire was administered. The results indicated no fall-off in reporting events associated with marked life changes (ie, salient events). In contrast, significant fall-off was observed for events characterized by varying degrees of desirability and anticipation. Although ratings of desirability and saliency were not independent, saliency of life events emerged as the dimension most closely associated with accuracy of event reporting. Research on the reliability of measures of life events and the association between event characteristics and illness should consider the kinds of systematic reporting differences observed here.

Aged↗
PubMed1987

Pulmonary fibrosis in asbestos insulation workers with lung cancer: a radiological and histopathological evaluation.

This study was undertaken to determine the relation between radiographic and histological manifestations of pulmonary asbestosis (interstitial fibrosis) in insulation workers who had died of lung cancer. Of 450 confirmed deaths from lung cancer a chest radiograph suitable for determining evidence of pneumoconiosis was obtained in 219. Of these cases, 138 also had a tissue specimen submitted that was suitable for histological study to determine the extent of histological fibrosis. There was a significant albeit limited correlation between the radiographic and histological findings (r = 0.27, p less than 0.0013). All 138 cases had histological evidence of parenchymal fibrosis; in 25 (18%), however, there was no radiographic evidence of parenchymal fibrosis. In 10 cases (7%) both parenchymal and pleural disease were undetectable on the radiograph. Thus a negative chest radiograph does not exclude the presence of interstitial fibrosis (asbestosis) in a substantial proportion of insulation workers previously exposed to asbestos who develop lung cancer.

Asbestos↗
PubMed1985

Saccadic eye movements among copper smelter workers.

Saccade accuracy was studied in 87 copper smelter workers. Findings were compared with those obtained in 52 lead-exposed automobile production workers and 52 controls examined as part of a separate study. Both groups of workers showed a decrease in saccade accuracy compared to controls. Saccade accuracy was reduced in copper smelter workers over 50 years of age compared to automobile production workers in this age group. Decreased saccade accuracy was not correlated with blood lead (Pb-B), zinc protoporphyrin (ZPP), or urinary arsenic (As-U) levels among copper smelter workers, but was significantly correlated with both Pb-B and ZPP in the group of automobile production workers. Saccade accuracy decreased significantly with age and duration of exposure only in the group of copper smelter workers. Complex exposures to lead and other toxic agents present in the smelter may account for the reduction in saccade accuracy among copper smelter workers.

Adolescent↗
PubMed1985

Urinary excretion of modified nucleosides in patients with acquired immune deficiency syndrome (AIDS) and individuals at high risk of AIDS.

Patients with certain malignant diseases excrete in their urine elevated levels of modified nucleosides originating from breakdown of transfer RNA (tRNA). A high incidence of acquired immune deficiency syndrome (AIDS), often associated with rapidly progressing Kaposi's sarcoma (KS), is currently being observed in many countries. Male homosexuals are considered to be at highest risk of developing these disorders. We have examined 10 patients with AIDS and 77 male homosexuals without clinical manifestations of AIDS at the time of examination. Elevated levels of modified nucleosides were found in all patients with AIDS. Of further interest was the finding of a high prevalence of abnormal nucleoside levels in the high-risk group, with a trend toward higher levels in those high-risk individuals who had lymphadenomegaly, considered a prodrome of AIDS. These findings indicate that determination of urinary nucleoside levels may help identify individuals at high risk of developing AIDS thereby increasing the possibility for prevention and early therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Occupational lead exposure. Effects on saccadic eye movements.

Quantitative measures of saccadic eye movements were examined in 52 lead exposed autobody shop workers and 52 age matched controls with no history of occupational lead exposure. Three characteristics of saccadic eye movements were studied: 1) saccade accuracy; 2) number of overshoots; and 3) maximum velocity. The results indicated that workers exposed to inorganic lead showed a decrease in saccade accuracy and an increase in overshoots compared with controls. Saccade maximum velocity was lower in lead exposed workers than in controls but the difference was just short of statistical significance. Correlations between measures of saccadic eye movements and indicators of lead absorption--blood lead (Pb-B) and zinc protoporphyrin (ZPP) levels--were analyzed in the lead exposed workers. Saccade accuracy was negatively correlated with both Pb-B and ZPP levels. The number of overshoots was not correlated with either Pb-B or ZPP levels. Saccade maximum velocity was not correlated with Pb-B, however, there was a significant negative correlation with ZPP. Age effects observed in the control group were disrupted in lead exposed workers. In addition, saccadic eye movements in younger workers (below 30 years old) were more affected by exposure to inorganic lead than were saccadic eye movements in older workers (50 years and older). It is proposed that these findings are consistent with a relatively rapid buildup of metabolically active lead burden observed in the study group. The data suggest that quantitative assessment of eye movements may be an important tool for studying subclinical central nervous system (CNS) dysfunction due to inorganic lead exposure.

Adult↗
PubMed1984

Distribution of blood lead, blood cadmium, urinary cadmium, and urinary arsenic levels in employees of a copper smelter.

A cross-sectional medical examination of a copper smelter work force included determination of blood lead (Pb-B), zinc protoporphyrin (ZPP), blood cadmium (Cd-B), urinary cadmium (Cd-U), and urinary arsenic (As-U), since it was known that such metal impurities were present in the copper concentrate. A total of 776 copper smelter employees (680 active and 96 retirees and ex-employees) were examined. Another 144 men, never employed in the smelter, but who had worked in copper mines (and sometimes in gold mines) were also examined. Mean Pb-B, ZPP, Cd-B, and As-U were significantly higher in active copper smelter employees than in retirees or miners, indicating exposure and absorption in the copper smelter. Significant correlations between Pb-B and Cd-B, and Cd-U and As-U were present, confirming the common source of absorption. Although there was evidence for an increased lead absorption, this was very moderate, with practically no Pb-B levels in excess of 60 micrograms/dl. A marked effect of smoking on blood cadmium levels was present; nevertheless, for all smoking categories Cd-B levels were significantly higher in active employees, indicating the independent contribution of exposure to cadmium in the smelter. Cd-U did not exceed 10 micrograms/g creatinine, the generally accepted "critical" level for the kidney, but was higher than 2 micrograms/g creatinine, a level very rarely exceeded in the general population, in a sizable proportion of those examined. The highest Cd-U levels were found in retired copper smelter employees; age might have been a contributing factor, besides a longer duration of exposure in the smelter.

Absorption↗
PubMed1984

Epidemiologic study of renal function in copper smelter workers.

A medical cross-sectional examination of a copper smelter work force was undertaken after environmental contamination with lead, cadmium and arsenic had been documented. A total of 920 subjects was examined, including active smelter employees, retired workers and copper mine employees who had never worked in the smelter. Slight to moderate absorption of lead and cadmium was definitely present in the active copper smelter employees, who had significantly higher levels of Pb-B, ZPP and Cd-B than retired employees and miners. Cd-U levels were higher in retired workers, who were also older and had, as a group, longer duration of exposure in the smelter. Cd-U did not exceed 10 micrograms/g creatinine, the level considered critical for nephrotoxicity, in any of the subjects. Median Cd-B level for active workers was 2.75 micrograms/L. Lead absorption was characterized by a relatively small proportion (16.7%) of active employees with Pb-B levels 40 micrograms/dL or higher. We were particularly interested in exploring the possibility that simultaneous exposure to lead and cadmium, although at levels not associated with nephrotoxicity for each metal separately, could result in renal function impairment. Distribution patterns of BUN and serum creatinine levels were unremarkable. Urinary beta 2-microglobulin levels were less than 200 micrograms/g creatinine in 95% of copper smelter employees. There were no significant correlations between urinary beta 2-microglobulin levels and Cd-U, Cd-B, Pb-B and ZPP or between urinary beta 2-microglobulin excretion and serum creatinine or BUN levels. Urinary beta 2-microglobulin levels were significantly correlated with age in the copper smelter workers, but not in the miners. Nevertheless, in the absence of any significant correlations between urinary beta 2-microglobulin and Cd-U, Cd-B, a causal relationship with cadmium absorption cannot be affirmed. That kidney function could be impaired by long-term exposure in the smelter was only indirectly suggested. Effects on renal function at the low levels of cadmium and lead absorption that were observed in this smelter population are minimal.

Adult↗
PubMed1983

Lead exposure and nerve conduction velocity: the differential time course of sensory and motor nerve effects.

Nerve conduction velocities (NCV) of the median motor, median sensory, peroneal motor, and sural nerves were measured on 40 lead-exposed automobile production workers as part of a comprehensive health survey. Blood lead (Pb-B) and blood zinc protoporphyrin (ZPP) were measured. The control group (N = 31) consisted of workers without lead exposure. All subjects were screened for the following conditions: Limb, neck or back injury, diabetes, neurological disease, and alcohol consumption of more than 28 alcoholic beverages per week. Limb temperature was assessed at three sites for each NCV measurement. The lead-exposed workers had slower median sensory NCV (42.9 vs. 46.8 m/sec, p less than 0.006) and slower sural NCV (37.8 vs. 42.8 m/sec, p less than 0.0004). All NCV estimates were then statistically adjusted for age and temperature, and transformed to Z values for further analyses. The mean standardized NCVs were slower in the lead-exposed group for the median sensory (-1.03 vs. -0.04, p less than 0.0003) and the sural nerves (-2.52 vs. -0.52, p less than 0.001). The study group was divided into two groups, with less than ten years and more than ten years of lead exposure. The subsample exposed less than ten years showed slowing of the median sensory (-0.94 vs. -0.04, p less than 0.005) and the sural nerves (-2.42 vs. -0.52, p less than 0.0001). Pb-B and ZPP levels were correlated with sural velocity (r = -0.54, p less than 0.04, and 4 = -49, p less than 0.06, respectively. Mean Pb-B was 59.7 micrograms/dl and mean ZPP was 175.8 micrograms/dl).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1982

Assessment of lead health hazards in a body shop of an automobile assembly plant.

This study of an occupationally lead-exposed group in the automobile assembly industry (body shop employees) has provided information with regard to current and recent lead-exposure levels characteristic for these operations. Comparison with findings in other, previously studied occupational groups (secondary smelter workers) indicated that current and recent lead exposure was significantly lower in the autobody shop employees. Prevalence of symptoms was found to be higher than in a control, non-lead-exposed group of maintenance workers in the same plant, but the differences reached the level of statistical significance only sporadically. Long-term effects on renal function, as reflected in blood urea nitrogen (BUN) and creatinine levels, were documented to be significant in this group of autobody shop employees. When compared with two secondary lead smelter populations previously studied, correlations between indicators of renal function, BUN and creatinine, and duration of lead exposure were consistently higher in the secondary lead smelter populations than in the group of autobody shop employees, although duration of lead exposure was greater in the latter. These findings are consistent with a dose-response relationship with regard to renal function impairment due to lead absorption. An increased prevalence of hypertension, especially diastolic, was also found, probably the consequence of renal effect.

Adult↗
PubMed1982

A composite index of lead effects. Comparative study of four occupational groups with different levels of lead absorption.

Biological indicators of lead effects on the central nervous system (CNS), hematogenous bone marrow, and kidney function as measured by performance tests, hemoglobin (Hgb) and BUN levels respectively were combined in an integrative index (INDEX). Such an index was calculated by removing age effects in measures of performance and kidney function and then transforming all the variables to Z (standard) units. The relationships between INDEX and biological indicators of lead exposure and absorption (Pb-B and ZPP) were studied in four groups: 191 non-lead exposed males (control group), 169 copper smelter workers, 133 autobody shop workers and 87 secondary lead smelter workers. We found that: 1) the magnitude of the correlation coefficient between INDEX and ZPP was much higher than were the correlations between the various single indicators of lead effects (performance test scores, Hgb, and BUN); and 2) the magnitude of the correlation coefficients was related to the degree of lead exposure and absorption (as reflected in distribution patterns of Pb-B and ZPP) in each group. The concept of an integrative index of biological effects of lead is important for the evaluation of early manifestations of lead toxicity and also for the correct assessment of adverse health effects of lesser intensity than those characteristic for the classic picture of overt lead poisoning.

Adult↗
PubMed1981

An integrative index of biological effects of lead.

Biological indicators of lead effects on the central nervous system (as measured by performance tests), hematogenous bone marrow (hemoglobin levels) and kidney function (BUN Levels) can be combined in an integrative index (INDEX). This integrative index can be in turn related to indicators of lead exposure and absorption. Such an index was calculated by removing age effects in measures of performance and kidney function and then transforming all the variables to Z (standard) units. Secondary lead smelter workers and a control group were studied. In secondary lead smelter workers this INDEX was found to be significantly correlated with ZPP, blood lead levels, and duration of lead exposure. In this population the magnitude of the correlation coefficients with ZPP levels was much higher than than for blood lead levels. INDEX had a higher correlation with ZPP than with each of its components: performance test scores, hemoglobin, and BUN levels. Although performance test scores, hemoglobin, and BUN levels were shown to discriminate between the control, non-lead-exposed population, and the lead-exposed group, INDEX (and particularly one pair of its components, CNS and hemoglobin levels) achieved the best discrimination between groups. The concept of an integrative index of biological effects of lead may be especially useful in defining populations at high risk for developing chronic, potentially irreversible neurologic and kidney dysfunction, and in assessing the severity of lead effects in individual cases.

Analysis of Variance↗
PubMed1980

Zinc protoporphyrin, blood lead and clinical symptoms in two occupational groups with low-level exposure to lead.

The results of cross-sectional clinical field surveys of 45 cable manufacturing workers and 90 telephone cable splicers are presented. Despite the rare occurrence of clinically overt lead poisoning among these occupational groups, high prevalence of lead-associated central nervous system symptoms and gastrointestinal symptoms was found. Hierarchical log-linear models for multidimensional contingency tables were fitted to those data and indicate that there is a partial correlation between reported symptoms and zinc protoporphyrin: individuals with high zinc protoporphyrin levels were more likely to report symptoms than those with low levels. No significant partial association was found between symptoms and blood lead. Because of the intermittent lead exposure encountered in one of the populations, individuals were identified with "normal" blood lead levels associated with "elevated" zinc protoporphyrin concentrations, thus indicating the difference in the biological significance between indicators of lead absorption (blood lead) and of biological response tests (ZPP). Suggestion is made that both types of diagnostic tests be utilized in the medical surveillance of lead-exposed workers.

Adult↗
PubMed1980

Kidney function and lead: relationships in several occupational groups with different levels of exposure.

Potential kidney function decrement with long term lead exposure is important in the overall assessment of adverse health effects of lead in industrial workers or other exposed groups. Two clinical field studies of secondary lead smelter workers have shown that a significant proportion of workers had slightly to moderately elevated blood urea nitrogen (BUN) and creatinine levels; the prevalence was higher in those with longer lead exposure. Since a decrement of kidney function with age has been documented, and since duration of lead exposure may also be strongly related to age, it was necessary to assess the age dependent renal function decrement in control (non-lead-exposed) populations. BUN and creatinine levels in the lead exposed workers showed a much more significant correlation with age than that which was found in the non-exposed populations; the correlation remained statistically significant after correcting for the age-dependent decrement derived from the control populations. Moreover, highly significant correlations between BUN and creatinine and the biological indicator of lead absorption, zinc protoporphyrin, were found. The results indicate a sizeable and significant decrement in kidney function in the secondary lead smelter workers studied; by removing its age-dependency, this effect was found to be lead-induced. In other occupational groups, with lesser and/or shorter lead exposure, a significant effect on renal function as reflected in BUN and creatinine levels could not be detected.

Adult↗
PubMed1980

Lead exposure and behavioral changes: comparisons of four occupational groups with different levels of lead absorption.

The association between lead absorption and objective psychological performance tests in five groups with different levels of lead absorption was studied in the following groups: (1) a control, non-lead-exposed group; (2) cable splicers, (3) cable manufactures, and (4) secondary lead smelter workers. The following performance tests were used: Block Design, Digit Symbol, and Embedded Figures. Age-corrected performance test scores and the average of three test scores (INDEX) were used throughout. A significant association between performance tests scores and increased lead absorption was found. Zinc protoporphyrin level was a more "powerful" (in the statistical sense) indicator of lead-induced CNS effects than blood lead levels. This study provides additional evidence that neurotoxic effects associated with occupational exposure to lead can be demonstrated by means of performance tests. It has been known and widely accepted that increased lead absorption is associated with "non-specific" subjective symptoms: tiredness, sleep disturbance, irritability, etc. Psychometric techniques (including an appropriate statistical analysis strategy) are highly sensitive for the early detection of CNS neurotoxicity, such as metal toxicity. Moreover, even in lead-exposed but asymptomatic individuals, a significant correlation (negative) between test scores and levels of lead absorption could be detected. It is concluded that workers exposed to lead at levels considered "safe" might be at risk of developing brain dysfunction with long term exposure.

Humans↗
PubMed1980

Health status of cable splicers with low-level exposure to lead: results of a clinical survey.

The results of a cross-sectional clinical field survey of 90 telephone cable splicers are presented. Despite the rare occurrence of clinically overt lead poisoning among cable splicers, the observed prevalence of symptoms was 29% for lead-associated central nervous system symptoms and 21% for gastrointestinal symptoms. These two groups of symptoms were directly related to zinc protoporphyrin (ZPP) levels but no relationship was found between them and blood lead concentrations. Only 5% of the workers had significantly elevated blood lead levels (greater than 40 microgram/100ml). Because of the intermittent lead exposure encountered in this trade, individuals were identified with "normal" blood lead levels associated with "elevated" zinc protoporphyrin concentrations, indicating the difference in biological significance between exposure-(blood lead) and biological-response tests (ZPP). Suggestion is made that both types of diagnostic tests be utilized in the medical surveillance of lead-exposured workers.

Adult↗
PubMed1979

The neurotoxicity of polybrominated biphenyls: results of a medical field survey.

Neurologic symptoms were the earliest and most prominent symptoms recorded in Michigan farm residents exposed to PBB as compared to a non-PBB exposed control farm population in Wisconsin. In Michigan (particularly among males) those who exhibited the most marked symptoms tended to show diminished performance as assessed by special tests, although population differences in performance were not as marked. Low indices of performance were also significantly correlated with intake of home-produced foodstuffs, particularly during the years 1972--1974 and store-bought products during the years 1975--1976. Between 1972 and 1976 the Michigan farm residents studied made significant changes in their consumption patterns of products suspected to be contaminated with PBB, as compared to those of Wisconsin farm residents. Serum PBB levels were not found to be significantly higher in Michigan males and females exhibiting the most prominent neurologic symptoms. Serum PBB levels were negatively correlated with performance test scores, particularly in males in older age groups.

Adolescent↗