New primers for promising single-copy genes in fungal phylogenetics and systematics.

Developing powerful phylogenetic markers is a key concern in fungal phylogenetics. Here we report degenerate primers that amplify the single-copy genes Mcm7 (MS456) and Tsr1 (MS277) across a wide range of Pezizomycotina (Ascomycota). Phylogenetic analyses of 59 taxa belonging to the Eurotiomycetes, Lecanoromycetes, Leotiomycetes, Lichinomycetes and Sordariomycetes, indicate the utility of these loci for fungal phylogenetics at taxonomic levels ranging from genus to class. We also tested the new primers in silico using sequences of Saccharomycotina, Taphrinomycotina and Basidiomycota to predict their potential of amplifying widely across the Fungi. The analyses suggest that the new primers will need no, or only minor sequence modifications to amplify Saccharomycotina, Taphrinomycotina and Basidiomycota.

Speciation of human microsporidia by polymerase chain reaction single-strand conformation polymorphism.

We describe the application of single-strand conformation polymorphism (SSCP) analysis to the speciation of human microsporidia after polymerase chain reaction (PCR) amplification with the panmicrosporidian primers PMP1 and PMP2. We compared the DNA extracted and amplified from different genotypes or isolates of Enterocytozoon bieneusi, Encephalitozoon cuniculi, E. hellem, and E. intestinalis plus an isolate of Vittaforma corneae. The PCR-SSCP, when performed at 20 degrees C, generated 2 bands in distinctive, reproducible patterns in polyacrylamide gels for each species of microsporidia tested, regardless of genotype or isolate. We found PCR-SSCP to be an easy and reproducible method for speciation of human microsporidia when the primer pair PMP1 and PMP2 is used.

Misclassification of physical work exposures as a design issue for musculoskeletal intervention studies.

OBJECTIVES: This study determined the impact of misclassification due to using job titles as surrogate variables for physical work exposures to assess confounding in a study of the preventive effect of back belts on back injury. The authors present retail merchandise data that quantify misclassification from residual confounding by physical work exposures on injury rate ratios when available administrative job titles are used. METHODS: Job title and direct observation data on 134 workers were used to calculate the percentage to which the job-title-adjusted rate ratio for back injury accounts for confounding by the true physical work exposures, awkward postures, and heavy weight handling. Workers' compensation data, an estimate of the effect of back belts from the literature, and the percentage of adjustment of the rate ratio due to the job title variable were used to calculate the magnitude of bias from the rate ratio adjusted for job title. RESULTS: The job title variable was found to have sensitivities of 97% and 85% and specificities of 68% and 58% for awkward postures and heavy weight handling, respectively. The magnitude of confounding bias remaining for the back-injury rate ratio when the job title surrogate was used was 24% for postures and 45% for heavy weight handling. CONCLUSIONS: The administrative job title performed poorly in this setting; residual confounding was sufficient to bias the rate ratio from 2.0 to 1.3. The effect of additional sources of misclassification and the need for better exposure measures than job title are discussed.

Performance of three enzyme immunoassays and two direct fluorescence assays for detection of Giardia lamblia in stool specimens preserved in ECOFIX.

ECOFIX is a single-vial stool preservative that is both formalin- and mercury-free. We evaluated the abilities of three commercial Giardia lamblia-specific enzyme immunoassays (EIAs) (ProSpecT Giardia Microplate Assay [Alexon-Trend Inc.], Giardia Test [Techlab], and Premier Giardia lamblia [Meridian Diagnostics, Inc.]) and two commercial direct fluorescent-antibody (FA) assays for G. lamblia (Crypto/Giardia IF Test [Techlab] and Merifluor Cryptosporidium/Giardia [Meridian Diagnostics, Inc.]) to detect G. lamblia in 34 G. lamblia-positive and 44 G. lamblia-negative stool specimens (determined by traditional examination for ova and parasites) preserved in ECOFIX compared to their abilities to detect G. lamblia in the same specimens preserved in formalin as the "gold standard" for each assay. Of the 34 formalin-fixed positive specimens, the number detected by each assay was as follows:, Alexon EIA, 34; Meridian EIA, 27; Techlab EIA, 29; Meridian FA assay, 31; and Techlab FA assay, 28. Both FA tests and the Alexon EIA performed well with ECOFIX, but the other two EIAs detected fewer positive specimens (the difference was statistically significant with the Techlab EIA) when ECOFIX was the preservative. Use of G. lamblia cyst antigen from cultured organisms preserved in formalin and ECOFIX demonstrated that the Alexon EIA could detect smaller amounts of antigen in ECOFIX than the other two EIAs could and suggested that cyst antigen is more stable in formalin. We recommend that laboratories use an FA assay or the Alexon EIA if they plan to use ECOFIX as their stool preservative.

Performance of para-Pak Ultra ECOFIX compared with Para-Pak Ultra formalin/mercuric chloride-based polyvinyl alcohol for concentration and permanent stained smears of stool parasites.

ECOFIX is a mercury and formalin-free fecal preservative that can be used for concentration of stool specimens and preparation of permanently-stained slides. In this study, the standard two-vial ParaPak Ultra system was compared with ECOFIX Ultra for the detection of intestinal parasites. A total of 261 specimens in 92 sets (77 with 3 specimens, 15 with 2 specimens) were collected in ECOFIX, formalin, and low viscosity polyvinyl alcohol (LV-PVA). Concentrations were performed from ECOFIX using Hemo-De and saline and from formalin using ethyl acetate and formalin. To prepare permanently-stained smears, ECOSTAIN (a modification of Wheatley's trichrome stain) was used on ECOFIX material and Wheatley's trichrome stain was used on specimens preserved in PVA. A total of 157 protozoa and helminths were detected; 132 (84.1%) were recovered in formalin/PVA and 129 (82.2%) in ECOFIX. In permanently-stained smears, 139 protozoa were observed, 116 (83.5%) in PVA-preserved material and 117 (84.2%) in ECOFIX. Fecal concentration yielded 111 parasites (103 protozoa and 8 helminths), of which 98 (88.3%) were detected in formalin-fixed stool and 48 (43.2%) in ECOFIX. Significantly fewer ECOFIX-preserved concentrates were positive for Blastocystis hominis (35 versus 15, p-value <0.001) and Endolimax nana (19 versus 2, p-value <0.001). In conclusion, use of the ECOFIX Ultra collection device in combination with ECOSTAIN resulted in largely comparable recovery of enteric parasites to the conventional two-vial ParaPak Ultra system when both sedimentation-concentration and permanently stained smears were performed, and 2-3 specimens per patient were evaluated.

Risk factors for back injury in 31,076 retail merchandise store workers.

Risk factors for work-associated strain or sprain back injuries were investigated in a cohort of 31,076 material handlers from 260 retail merchandise stores in the United States. The workers studied were those with significant material-handling responsibilities--daily lifting and movement of merchandise. Workers in jobs with the greatest physical work requirements had an injury rate of 3.64 per 100 person-years versus 1.82 in workers with lesser work requirements. The unadjusted injury rate for males was 3.67 per 100 person-years compared with 2.34 per 100 person-years for females, but the excess for males was confounded by higher physical work requirements for men in the stocker/receiver job category. The injury rate ratio for short versus long duration of employment was 3.53 (95% confidence interval: 2.90, 4.30); for medium versus long duration of employment, it was 1.38 (95% confidence interval: 1.18, 1.62). The elevated rate ratios were maintained when the data were stratified by subsets with different rates of turnover. The results suggest that workers with the greatest physical work requirements and those with the shortest duration of employment are at the highest risk of back injuries. However, selection forces causing worker turnover within this cohort of active workers are not well characterized and have the potential to bias the measures for time-related factors such as duration of employment.

Workplace changes associated with a reduction in musculoskeletal symptoms in office workers.

The purpose of this study was to identify factors associated with reductions observed in musculoskeletal symptoms when office workers were moved to a new building. A questionnaire including items regarding symptoms and aspects of the work environment was administered to 577 office workers before and after they were moved from nine buildings to a single new facility in 1992. Employees working in two reference buildings, where they remained throughout the study period, were also surveyed. Two musculoskeletal outcomes, hand/arm and neck/shoulder/back, were selected for study. In matched multivariate analyses, the reduction in hand/arm symptoms from 1992 to 1993 was associated with improved satisfaction with the physical workstation (odds ratio [OR] = 2.0); the reduction in neck/shoulder/back symptoms was associated with improved chair comfort (OR = 1.8), fewer housekeeping responsibilities (OR = 3.6), female gender (OR = 1.8), and low pay range (OR = 1.7). Longitudinal results suggested that changes in workstations resulted in decreased symptoms. Results of this investigation might be used to develop workplace changes that result in reductions of musculoskeletal disorders.

Employees exposed to lead in Washington state nonconstruction workplaces: a starting point for hazard surveillance.

A survey of selected Washington state employers was carried out to (1) determine the number of employees working in lead-using businesses, (2) characterize processes and tasks where exposures occur, and (3) determine the number of employers familiar with the lead standard, lead health effects, and how exposures can be controlled. A total of 1822 nonconstruction employers likely to use lead were identified using Washington State Department of Labor and Industries files, telephone directories, Washington State Department of Ecology files, air sampling results from state workplace inspections, and the state's Adult Blood Lead Registry. A total of 89.5% of employers returned the mail questionnaire. Of 789 employers responding that they engaged in lead-using tasks, 45% stated they were aware there was an Occupational Safety and Health Administration standard for lead, 21% had done air sampling for lead, 17% had done blood-lead screening, and 76% reported some type of industrial hygiene measures to control exposures. The most commonly reported lead-using activities included soldering; auto repair; scrap metal handling; sanding; cutting or welding surfaces coated with leaded materials; painting with leaded paints; and radiator repair. A total of 18,970 nonconstruction workers (and 9416 construction workers) were estimated to be lead-exposed in Washington in 1995. Identification of potentially exposed workers through hazard surveillance and characterization of workplace knowledge and practices (through survey and the registry) has allowed the Department of Labor and Industries to target resources toward industries most in need of exposure reduction efforts.

Falls in construction: injury rates for OSHA-inspected employers before and after citation for violating the Washington State Fall Protection Standard.

This study examined the relationship between Washington's fall protection standard and injuries in construction workers. Workers' compensation claim rates for falls were examined for employers that were cited for violating the standard over the 1991-1992 period. Fall injury rates for the periods before and after inspections were compared. Claims for a control group of employers that had not been cited were also examined. For the 784 cited employers, the claim rate for compensable fall injuries decreased from 1.78 to 1.39 per 200,000 hours worked for the one-year periods before and after inspection. For the control group (n = 8,301), the claim rate decreased from 1.04 to 0.95 per 200,000 hours. Cited employers were 2.3 times as likely as control employers (p < 0.0001) to experience a claim rate reduction, after adjustment for employer size and type of business. Results suggested that industry-wide fall injury rates might be expected to decrease if more employers were inspected.

Washington State's late night retail worker crime protection regulation. Relationships with employer practices.

Washington's late night retail worker crime protection regulation, enforced by the state Occupational Safety and Health Administration (OSHA) program, was intended to prevent injuries by deterring violent crimes. We investigated whether the regulation was associated with businesses' violence prevention activities. We surveyed 1,516 employers at high risk of robbery, including gas stations, groceries, hotels, restaurants, and taverns, in 1995 to determine whether they had violence prevention training programs for their employees (a requirement of the standard). Awareness of the regulation was low (4.4%). Employers covered by the regulation were more likely to have programs (Odds Ratio [OR] = 1.4), as were those aware of a regulation (OR = 3.4). State OSHA plan contact (an inspection or consultation) was also associated with having a program (OR = 1.9). Despite low awareness of the standard, results suggested that regulatory efforts to protect high-risk employees were associated with employers' robbery and crime prevention activities.

Fatal and nonfatal injuries related to violence in Washington workplaces, 1992.

This study describes injuries related to assaults and violence that occurred in Washington State workplaces in 1992. Nonfatal injuries are emphasized. High-risk industries and occupations are described. Fatalities caused by work-related violence were identified using the 1992 U.S. Department of Labor Bureau of Labor Statistics (BLS) Census of Fatal Occupational Injuries. Nonfatal injuries were identified using the BLS Annual Survey of Occupational Injuries and Illnesses and the Washington State workers' compensation system. Thirteen occupational fatalities resulted from assaults or violent acts in 1992. BLS data identified 784 nonfatal injuries that resulted in one or more day off work; workers' compensation data identified 2,395 claims. Industries experiencing the highest claim rates were Social Services (148 per 10,000) and Health Services (106 per 10,000). Nonfatal violent injuries were common and appeared to have different risk factors than fatal injuries. Industries in which injuries occurred were often predictable and suggested specific strategies for prevention efforts.

Sheep red blood cell and Brucella abortus antibody responses in chickens selected for multitrait immunocompetence.

Chickens from replicated lines divergently selected for multitrait immunocompetence were tested for their antibody responses to sheep red blood cells and Brucella abortus antigen. All birds were injected with sheep red blood cells and B. abortus antigens at 4 and 9 wk of age, and blood samples were taken 6, 8, and 10 d postimmunization. Antibody titers were determined by using agglutination assays. For sheep red blood cell responses, the most marked difference was between the high and low lines postsecondary immunization. The high line titer was still rising at 10 d, whereas the low line had reached its peak at 8 d and was decreasing. This may be a result of the selection process in which the high line is selected for a high, persistent response to two T cell-dependent antigens at 3 wk postimmunization. For B. abortus responses, the only differences were between high and low lines postsecondary immunization. The high lines were always higher than the low lines, with differences getting smaller as time postimmunization increased. In summary, selection for multitrait immunocompetence resulted in changes in antibody response to unrelated antigens.

Identification of microsporidia in stool specimens by using PCR and restriction endonucleases.

We report the development of a PCR-based assay for the detection of microsporidia in clinical specimens. A single primer pair complementary to conserved sequences of the small-subunit rRNA enabled amplification of DNA from the four major microsporidian pathogens of humans: Encephalitozoon cuniculi, Encephalitozoon hellem, Enterocytozoon bieneusi, and Septata intestinalis. The extraction method allowed PCR amplification of E. bieneusi and S. intestinalis DNA from sodium hypochlorite-treated stool specimens. Differentiation of the microsporidian gastrointestinal pathogens E. bieneusi and S. intestinalis could be accomplished by restriction endonuclease digestion of PCR products using PstI and HaeIII.

Health symptoms and the work environment in four nonproblem United States office buildings.

OBJECTIVES: The objective of this study was to quantify health symptom reports in four "nonproblem" buildings and to assess the relationship between symptoms and air quality measures, workstation characteristics, and psychosocial aspects of the workplace. METHODS: Environmental sampling was conducted in four office buildings occupied by employees working for the state of Washington in March of 1992. A questionnaire was concurrently administered to building occupants. RESULTS: While measured contaminant levels were low, symptoms were frequent. Fifty-five percent of the 646 respondents reported recent symptoms which affected the eyes, nose, or throat and improved when away from work. Symptoms were not associated with measured contaminant levels, but, rather, with perceptions about air movement, dryness, odors, and noise. Psychosocial factors were less strongly associated with symptoms. CONCLUSIONS: Even in nonproblem buildings, symptom reports can be frequent and may represent overall satisfaction with the work environment. In response to symptoms ascribed to air quality problems, it may be appropriate to address employee perceptions regarding the work environment in addition to evaluating environmental characteristics relating to chemicals, biological contamination, air movement, temperature, and humidity.

Development and evaluation of a rapid and simple procedure for detection of Pneumocystis carinii by PCR.

We report the development of a simplified PCR-based assay for the detection of Pneumocystis carinii DNA in clinical specimens. The adoption of a rapid DNA extraction procedure and the introduction of a type of enzyme-linked immunosorbent assay for PCR product detection enabled this procedure to be carried out in a single working day in a clinical microbiology laboratory. The PCR assay was prospectively compared with an immunofluorescent-antibody (FA) staining method for the detection of P. carinii in induced sputum and bronchoalveolar lavage (BAL) specimens. The results of the study showed that, for induced sputum specimens, FA staining had a sensitivity of 78% (32 of 41 specimens) and a specificity of 100% (166 of 166 specimens); PCR was 100% (41 of 41 specimens) sensitive and 98% (162 of 166 specimens) specific. For BAL specimens, FA staining was 100% sensitive (21 of 21 specimens) and 100% specific (133 of 133 specimens), and PCR had a sensitivity of 100% (21 of 21 specimens) and a specificity of 99% (132 of 133 specimens). These results strongly suggest that use of our PCR-based assay could effect clinically useful improvements in the sensitivity of induced sputum specimens for the detection of P. carinii.

A case-control study of chronic neuropsychiatric disease and organic solvent exposure in automobile assembly plant workers.

A case-control study of chronic neurological and psychiatric disease and occupational exposure to solvents was carried out in eight automobile assembly plants. Cases included 299 subjects who were granted medical disability retirement in 1980-8. Two control groups were selected, the first from those granted retirement in the same period because of medical disability from causes unrelated to solvent exposure. The second included hourly employees from the plant population. In these facilities, solvent exposures tended to be short term and low level, although common: the average duration of exposure was 2.3 years; about 41% experienced at least one day of exposure. Of those exposed, 46% had less than one year of exposure. Results for all psychiatric disease combined (273 cases) suggested that cases had lower exposures than either control group, regardless of how exposure was expressed. Results could not be explained by conventional confounding exposures or characteristics or by usual manifestations of the healthy worker effect. By contrast, chronic neurological disease, and multiple sclerosis in particular, seemed to be associated with exposure, although few cases were identified and observed increases in risk were not statistically significant.

Cumulative trauma disorders of the hand and wrist in the auto industry.

Surveillance for cumulative trauma disorders (CTDs) of the hand and wrist was carried out in five US automotive plants from 1985 to 1986, using Occupational Safety and Health Administration (OSHA) Form 200 injury and illness logs and medical insurance claims. Results using both record sources indicated that hand and wrist disorders may be more common in foundries than in other types of automotive plants. Similarly, in assembly plants, employees in certain departments appeared to be at higher risk for CTDs. Although our results are based on small numbers of cases, they suggest plants and departments that might be targeted for more detailed investigation.

Improved diagnosis of Pneumocystis carinii infection by polymerase chain reaction on induced sputum and blood.

Detection of Pneumocystis carinii by the polymerase chain reaction (PCR) may facilitate non-invasive diagnosis of P carinii pneumonia and study of its epidemiology. We have compared the sensitivity and specificity of two PCR methods with those of conventional staining for detection of P carinii in induced sputum, bronchoalveolar lavage fluid (BAL), and blood. Of 71 sputum samples, 17 were from patients with microbiologically confirmed P carinii pneumonia. A nested PCR method correctly identified the presence of P carinii in all 17 (100% sensitive, 95% confidence interval [CI] 81-100%) and found no organisms in 50 of 54 microbiologically negative samples (93% specific, 95% CI 82-98%). PCR with a single primer pair was 71% sensitive (44-90%) and 94% specific (85-99%). The sensitivity of conventional staining methods (direct and indirect fluorescence antibody and toluidine-blue-O tests) was significantly less (38-53%) than that of nested PCR (p less than 0.05). In BAL, neither PCR method was significantly better than the conventional staining methods. P carinii was detected in BAL or sputum from 10 immunocompromised patients without microbiological evidence of P carinii pneumonia, which suggests that symptom-free carriers or subclinical infection can exist. P carinii was detected by nested PCR in blood from 2 of 3 patients with disseminated pneumocystosis but in only 1 of 11 patients with P carinii infection restricted to the lungs. Nested PCR on induced sputum is more sensitive than conventional staining methods for the diagnosis of P carinii pneumonia and provides a non-invasive method of detecting disseminated disease.

Use of medical insurance claims for surveillance of occupational disease. An analysis of cumulative trauma in the auto industry.

Medical insurance claims, linked with work histories for a large automotive manufacturer over a 3-year period, identified large numbers of cases of potentially work-related diseases, including 30,600 episodes of probable cumulative trauma disorders (CTD). CTD incidence rates were calculated within five plants, and high-risk areas identified, however, unknown differences in medical insurance coverage by exposure group limited interpretation. Case-control analyses, with controls also identified by insurance claims, addressed coverage and produced age-adjusted and sex-adjusted estimates of risks. All five plants had departments with statistically significant, elevated risks for one or more of the diagnoses carpal tunnel syndrome, CTD of other upper extremities, rotator cuff syndrome, CTD of the neck and of the lower back. Medical insurance claim data linked with work history provide the basis for practical and comprehensive surveillance for CTD and potentially a variety of other occupational diseases.

Solvent nephrotoxicity in humans and experimental animals.

Evidence from human case reports, epidemiologic studies and animal experiments have suggested that exposure to organic solvents is associated with a wide spectrum of renal disorders, including tubular necrosis, interstitial disease, glomerulonephritis and neoplasia. This review summarizes what is known about solvent-induced renal damage in humans and experimental animals, with emphasis on hypothesized mechanisms by which this broad range of disorders may occur.