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Biomedical subjects

M L Bleecker

Publications and source records attributed to M L Bleecker.

At least 37 records · Page 2Linked to original sources
PubMed1990

Solvent-associated decrements in olfactory function in paint manufacturing workers.

To assess the effects of low-level organic solvent exposure on olfactory function, a cross-sectional study in paint manufacturing workers was undertaken. Workers in two paint manufacturing facilities (N = 187) were tested using the University of Pennsylvania Smell Identification Test (UPSIT), a standardized, quantitative test of olfactory function. Industrial hygiene air samples over the past 13-15 years revealed that average solvent exposures in these plants were 2-40% of the existing threshold limit values for the three chemicals measured. Stratification by smoking status revealed evidence of dose-related decrements in olfactory function (p = .01) only in non-smokers. Furthermore, those nonsmoking workers in the highest exposure category had UPSIT scores below the fifth percentile for their age. These results suggest that solvents may cause nervous system dysfunction at lower levels than previously suspected, and that the olfactory system may be a critical target organ for the neurotoxic effects of solvents and other chemicals.

Adult↗
PubMed1990

Subclinical neuropsychiatric effects of chronic low-level solvent exposure in US paint manufacturers.

In the present study, 187 workers at two US paint manufacturing plants were assessed for symptoms of painters syndrome using the Zung Depression Index, Scandinavian Questionnaire 16, and the Present State Exam. No significant associations were found between solvent exposure and total scores, although a sum of individual questions related to depression on the Present State Exam was found to be related to both health status and exposure. The clinical relevance of these findings is discussed. Overall, exposure was not associated with the constellation of symptoms characteristic of the painters' syndrome.

Adult↗
PubMed1989

Absence of depression in elderly adults.

Depressive symptomatology has been reported to be most prevalent over the age of 65. This study examined the effects of age (young less than or equal to 60 years, old greater than 60 years) and sex on the Beck Depression Inventory (BDI), MMPI Scale 2 (Depression), and Geriatric Depression Scale (GDS). Responses to somatic versus psychological complaints on the BDI were examined separately, and the physical malfunctioning subscale (D3) of the MMPI-2 was also evaluated. No age effects were found on any of the depression scales' total scores. On the BDI, the older group reported more somatic complaints than the younger group. Psychological complaints were reported equally for young and old groups. Women reported more depressed items on the MMPI-2 and reported a greater number of symptoms of physical malfunctioning (D3) than men for both age groups. No age by sex interaction reached significance. A report of greater physical malfunctioning (D3) was significantly associated with higher scores on all the depression scales. The increased prevalence of somatic complaints on self-report depression scales probably results in higher scores, which are misinterpreted as representing more depression in the elderly population. It is recommended that a depression scale such as the GDS, which excludes somatic items, be used to assess depression in older adults.

Adult↗
PubMed1989

The MMPI: regional difference or normal aging?

The Minnesota Multiphasic Personality Inventory (MMPI) is currently undergoing a process of revision and renormalization. Of particular concern is whether or not there is a need to develop separate normative tables for elderly subjects. Colligan, Osborne, Swenson, & Offord (1983) tested a large group of healthy subjects who ranged in age from 18 through 99. Their investigation uncovered numerous significant relationships between test taker age and scores on various scales of the MMPI. The present study looked at the MMPI profiles of 214 healthy men and women between the ages of 39 and 89. The results gleaned from this investigation do not reflect the same intensity of age-related changes that are reported by Colligan et al. (1983) and other similar studies. More specifically, we were unable to detect the age-related elevations in the "neurotic triad" (Hs, D, Hy scales) that have often been cited by other researchers. Additionally, we were not able to support the typically reported aging effects in scales Mf, Pa, Pt, and Si. We suggest that these and other similar differences may be attributed to geographic, societal, and population factors.

Adult↗
PubMed1988

Age-related sex differences in verbal memory.

Verbal learning and memory were studied in 196 healthy men and women aged 40 to 89. The Rey Auditory Verbal Learning Task (RAVLT), a 15-word list, was presented over five trials followed by free recall after each trial. A recognition trial of 50 words subsequently was administered. A stepwise regression that examined the contributions of age, sex, and vocabulary on the five trials of the RAVLT showed that age and sex accounted for a significant portion of the variance on each trial. Vocabulary accounted for a significant portion of the variance only on trials 4 and 5. The recognition trial was not affected by age, sex, or vocabulary. Men had lower scores overall as compared to women. In the older age group (ages 66-89), this difference was significant on trials two through five. Possible mechanisms that may underlie these age-related sex differences in learning curves are discussed.

Adult↗
PubMed1988

Age-specific norms for the Mini-Mental State Exam.

We administered the Mini-Mental State Exam (MMSE) to 194 healthy men and women, ages 40 to 89 years. Total score was significantly associated with age (p less than 0.0001), but not vocabulary, education, Beck's Depression Inventory Score, or sex. The lowest quartile cutoff scores for the MMSE by decade were 40s - 29; 50s - 28; 60s - 28; 70s - 28; and 80s - 26. When screening for progressive decline in cognitive performance, the use of age-specific norms may provide greater sensitivity than the present recommended cutoff score of less than 24.

Adult↗
PubMed1988

Conditioning of physical symptoms after neurotoxic exposure.

Psychologic reactions to a neurotoxic exposure can produce prolonged physical symptoms which are as debilitating as the direct effects of the neurotoxic substance. A group of patients exist who experience reoccurrence of exposure-related symptoms when exposed to a variety of common environmental substances, such as perfume, gasoline, and cigarette smoke. We propose a classical conditioning model to explain the development of this phenomenon. Identification and treatment of these individuals are also discussed.

Adult↗
PubMed1987

Medical surveillance for carpal tunnel syndrome in workers.

Carpal canal size was examined as a risk factor associated with carpal tunnel syndrome in the workplace. Seven of 14 electricians had symptoms of carpal tunnel syndrome. When cross-sectional areas were measured by computed tomography (CT), affected workers had a cross-sectional area of 1.75 +/- 0.21 cm2; control values were 2.53 +/- 0.15 cm2 (p less than 0.05). Subjects with a subclinical syndrome had an area of 1.83 +/- 0.22 cm2, which was similar to the group with symptoms. Wrist circumference was not a predictor of the smallest carpal canal area. Unusual bony and soft tissue structures within the carpal canal were easily identified with CT.

Adult↗
PubMed1987

Risk of astrocytic brain tumors associated with occupational chemical exposures. A case-referent study.

A case-referent study was conducted on the risk of brain tumors among workers exposed to organic chemicals in petroleum refining and chemical manufacturing. Brain tumor cases in northern New Jersey, Philadelphia, and the Gulf Coast of Louisiana were identified from death certificates of a recent three-year period. The cases (N = 300) were white men aged greater than or equal to 30 years with a confirmed diagnosis of glioblastoma multiforme, astrocytoma, or a mixed glioma with astrocytic cells. The referents (N = 386) were white men who died from causes other than brain tumor, epilepsy, cerebrovascular disease, suicide, or homicide and were frequency-matched with the cases on age at death, year of death, and study area. Next-of-kin were interviewed for complete occupational histories. No statistically significantly elevated odds ratios (OR) were associated with employment in the chemical industry. The risk of astrocytic tumors was elevated among the subjects with production or maintenance jobs in petroleum refining (OR 1.7, 95% confidence interval 0.7-4.2); however, it decreased with duration employed. There were nonsignificant excess risks of astrocytic tumors among the men exposed to cutting fluids (OR 1.6) or organic solvents (OR 1.3), and also among the subjects exposed to lubricating oils (OR 1.4), organic solvents (OR 1.5), or cutting fluids (OR 1.8) for greater than or equal to 20 years.

Astrocytoma↗
PubMed1987

New techniques for the diagnosis of carpal tunnel syndrome.

An overview is presented of the assessment of carpal tunnel syndrome (CTS) in manual workers, with emphasis on the distinction from other compression syndromes and from diffuse polyneuropathy. Clinical examinations, electrodiagnostic studies, the determination of vibration threshold, thermography, and, recently, computerized tomography have been used. This last-mentioned method has also been employed in a study indicating that a subgroup of the general population may possess a risk factor, small carpal canal, associated with the development of CTS.

Carpal Tunnel Syndrome↗
PubMed1987

Constant current sine wave transcutaneous nerve stimulation for the evaluation of peripheral neuropathy.

We have evaluated various forms of peripheral neuropathy with a new device which emits a constant sinusoid stimulus at varying frequencies to quantitate current perception thresholds (CPTs). In normal individuals, CPT measures increase with increasing stimulation frequency, are highest on the toe and lowest on the face. There is a significant effect of age and sex on threshold perception. In patients with neuropathy, there is a marked increase in thresholds on hands and feet, as well as a lesser but still significant increase of facial CPTs. Thresholds furthermore correlated with clinical severity in a group of patients with diabetic neuropathy. Facial thresholds were markedly elevated in the patients with moderate to severe neuropathy, suggesting that the device is sensitive to the systemic nature of peripheral neuropathy. The authors believe the device will be a useful tool in screening for sensory neurologic abnormalities.

Adult↗
PubMed1987

Brain tumor mortality risk among men with electrical and electronics jobs: a case-control study.

Brain tumor risk associated with electrical and electronics jobs and with occupational exposure to microwave and radiofrequency (MW/RF) electromagnetic radiation was evaluated with the use of data from a death certificate-based case-control study of brain tumors and occupational risk factors in northern New Jersey, Philadelphia, PA, and southern Louisiana. Next-of-kin of 435 white men who died of a primary brain tumor and of 386 controls who died from other causes were interviewed to obtain information on lifetime occupational history and other factors that might be related to excess brain tumor risk. The relative risk (RR) for all brain tumors was elevated among men exposed to MW/RF radiation [RR = 1.6; 95% confidence interval (Cl) = 1.0, 2.4] and was significantly elevated among men exposed for 20 or more years. All of the excess risk for MW/RF radiation-exposed subjects was derived from jobs that involved the design, manufacture, repair, or installation of electrical or electronic equipment (RR = 2.3; 95% Cl = 1.3, 4.2), while risk of brain tumors among MW/RF radiation-exposed subjects who never worked in electrical or electronics jobs was not elevated (RR = 1.0; 95% Cl = 0.5, 1.9). Furthermore, risk was elevated for electronics workers who were considered to have no exposure to MW/RF radiation. Among electrical and electronics workers, risk was highest for engineers, teachers, technicians, repairers, and assemblers combined (RR = 3.9; 95% Cl = 1.6, 9.9) and was limited to excess risk from astrocytic tumors (RR = 4.6; 95% Cl = 1.9, 12.2). Risk of astrocytic tumors among these electronics manufacture and repair workers increased with duration of exposure to tenfold among those employed for 20 or more years. Among electricians and power and telephone linemen combined (electrical tradesmen), the RR for astrocytic tumors was slightly elevated, but not statistically significant (RR = 1.8), and showed no consistent evidence of a duration-response relationship. Electrical tradesmen are exposed to extremely low frequency electromagnetic radiation, while men in some jobs associated with electronics manufacture and repair are exposed to electromagnetic radiation in the very high frequency and ultra-high frequency ranges and also may be exposed to soldering fumes, solvents, and a variety of other chemicals.

Astrocytoma↗
PubMed1987

Neuropsychological impairment following inorganic arsenic exposure.

A 50-year-old chemical engineer, routinely screened for occupational arsenic exposure, was admitted with a delirium for which no known etiology was found. Elevated levels of arsenic were found in the urine and hair. The patient received chelation treatment with British anti-Lewisite; substantial amounts of arsenic were excreted and the toxic encephalopathy improved gradually over the 8-month follow-up period. The patient was tested at 6 weeks, 4 months, and 8 months postdelirium with a battery of neuropsychological tasks. The pattern of results showed verbal learning and memory to be severely impaired while tests of general intellectual abilities and language remained unaffected. Follow-up examinations with no subsequent reexposure revealed improvements on specific cognitive tasks. It is unclear whether recovery of cortical functions occurred or if compensatory strategies were developed. It is proposed that a subacute exposure to arsenic may have contributed to the neuropsychological deficits.

Arsenic↗
PubMed1986

Neuropathy target esterase in human lymphocytes and platelets.

The target enzyme in organophosphorous-induced delayed neuropathy (OPIDN) has been designated neuropathy target esterase or neurotoxic esterase (NTE). NTE activity can be measured in blood lymphocytes and platelets, which could be of use as biomonitors in man at risk for the development of OPIDN. Separation of lymphocytes and platelets from whole blood, recovery, purity, storage and expression of data were examined. A substantial amount of the NTE activity of a human lymphocyte preparation made using Ficoll/Pacque was due to contamination by platelets; further purification was achieved by sucrose-gradient centrifugation. In an easily prepared sample of human platelets less than 10% of NTE was associated with contaminating white cells. We were unable to preserve NTE activity of platelets or lymphocytes at -80 degrees C either 'dry' or with added buffer and glycerol. In 68 male subjects, NTE activity in platelets averaged 8.36 +/- 1.54 nmol min-1 mg protein-1 and NTE activity in lymphocytes, obtained from blood after removal of platelets, 13.34 +/- 2.42 nmol min-1 mg protein-1. A good correlation was found between platelet and lymphocyte NTE activity. NTE activity in platelets may be a preferable method for measuring exposure to axonopathic organophosphorous compounds because of the ease and purity of separation. No correlation with other neuropathic risk factors such as age, smoking and alcohol intake was noted.

Adult↗
PubMed1986

Vibration perception thresholds in entrapment and toxic neuropathies.

Due to the ever-increasing problems associated with carpal tunnel syndrome in the workplace where exposure to neurotoxic substances may also occur, measure of nerve function addressing both of these neuropathies is needed. Limitations in the standard neurological examination and nerve conduction studies have resulted in efforts to develop portable instruments for quantitative sensory testing. Fingertip vibration perception is altered in carpal tunnel syndrome and toxic neuropathies. Vibration perception is described for the median-innervated II digit and the ulnar-innervated V digit using an Optacon tactile stimulator. Discussion focuses on the interaction between toxic and entrapment neuropathies as reflected by vibration thresholds.

Carpal Tunnel Syndrome↗
PubMed1986

New screening device for assessment of peripheral neuropathy.

Screening for the onset of toxic and entrapment neuropathy is a major concern in occupational medicine today. Current perception thresholds may be used as a measure of the integrity of the peripheral nervous system. A new transcutaneous nerve stimulator was used to evaluate current perception thresholds in 54 normal persons and 33 diabetic subjects. Current perception thresholds in the normal volunteers with no evidence of peripheral neuropathy were found to vary significantly with the frequency and location of the stimulation, as well as age. The test identified the diabetic peripheral neuropathy with an overall sensitivity of 94%. This new diagnostic technique is quick, simple to perform, noninvasive and nonaversive and provides a sensitive quantitative measure of sensory function. This diagnostic stimulator will be useful for screening occupationally related toxic and entrapment neuropathies in which sensory impairment is an early finding.

Adult↗