Identification of target mRNAs for the clock-controlled RNA-binding protein Chlamy 1 from Chlamydomonas reinhardtii.

An endogenous clock regulates the temporal expression of genes/mRNAs that are involved in the circadian output pathway. In the green alga Chlamydomonas reinhardtii, a clock-controlled RNA-binding protein (Chlamy 1) was identified recently, which represents an analog of the circadian trans-acting factor CCTR from the phylogenetically diverse alga Gonyaulax polyedra. In order to identify in C. reinhardtii target mRNAs that can be recognized by Chlamy 1, gel mobility-shift assays and UV-crosslinking experiments were carried out, and revealed that this protein interacts specifically with the 3' untranslated regions of several mRNAs and recognizes them all via a common cis-acting element, composed of at least seven UG repeats. By using competition assays, it was found that the affinity of Chlamy 1 is highest for mRNAs whose products are key components of nitrogen and CO2 metabolism. Since the activities of enzymes involved in nitrogen metabolism vary in a temporal pattern that is opposite in phase to that of Chlamy 1 binding activity, the protein may repress the translation of the cognate mRNAs.

Hospital safety climate and its relationship with safe work practices and workplace exposure incidents.

BACKGROUND: In the industrial setting, employee perceptions regarding their organization's commitment to safety (i.e., safety climate) have been shown to be important correlates to both the adoption and maintenance of safe work practices and to workplace injury rates. However, safety climate measures specific to the hospital setting have rarely been evaluated. This study was designed to develop a short and effective tool to measure hospital safety climate with respect to institutional commitment to bloodborne pathogen risk management programs and to assess the relationship between hospital safety climate and (1) employee compliance with safe work practices and (2) incidents of workplace exposure to blood and other body fluids. METHODS: A questionnaire, which included 46 safety climate items, was developed and tested on a sample of 789 hospital-based health care workers at risk for bloodborne pathogen exposure incidents. RESULTS: A 20-item hospital safety climate scale that measures hospitals' commitment to bloodborne pathogen risk management programs was extracted through factor analysis from the 46 safety climate items. This new hospital safety climate scale subfactored into 6 different organizational dimensions: (1) senior management support for safety programs, (2) absence of workplace barriers to safe work practices, (3) cleanliness and orderliness of the work site, (4) minimal conflict and good communication among staff members, (5) frequent safety-related feedback/training by supervisors, and (6) availability of personal protective equipment and engineering controls. Of these, senior management support for safety programs, absence of workplace barriers to safe work practices, and cleanliness/orderliness of the work site were significantly related to compliance (P<.05). In addition, both senior management support for safety programs and frequent safety-related feedback/training were significantly related to workplace exposure incidents (P<.05). Thus the most significant finding in terms of enhancing compliance and reducing exposure incidents was the importance of the perception that senior management was supportive of the bloodborne pathogen safety program. CONCLUSIONS: Hospital safety climate with regards to bloodborne pathogens can be measured by using a short, 20-question scale that measures 6 separate dimensions. Whereas all 6 dimensions are essential elements of overall safety climate, 3 dimensions are significantly correlated with compliance, and 1 dimension (senior management support) is especially significant with regard to both compliance and exposure incidents. This short safety climate scale can be a useful tool for evaluating hospital employees' perceptions regarding their organization's bloodborne pathogens management program. In addition, because this scale measures specific dimensions of the safety climate, it can be used to target problem areas and guide the development of intervention strategies to reduce occupational exposure incidents to blood and other body fluids.

Defining regions of the Y-chromosome responsible for male infertility and identification of a fourth AZF region (AZFd) by Y-chromosome microdeletion detection.

Cytogenetic and molecular deletion analyses of azoospermic and oligozoospermic males have suggested the existence of AZoospermia Factor(s) (AZF) residing in deletion intervals 5 and 6 of the human Y-chromosome and coinciding with three functional regions associated with spermatogenic failure. Nonpolymorphic microdeletions in AZF are associated with a broad spectrum of testicular phenotypes. Unfortunately, Sequence Tagged Sites (STSs) employed in screening protocols range broadly in number and mapsite and may be polymorphic. To thoroughly analyze the AZF region(s) and any correlations that may be drawn between genotype and phenotype, we describe the design of nine multiplex PCR reactions derived from analysis of 136 loci. Each multiplex contains 4-8 STS primer pairs, amplifying a total of 48 Y-linked STSs. Each multiplex consists of one positive control: either SMCX or MIC2. We screened four populations of males with these STSs. Population I consisted of 278 patients diagnosed as having significant male factor infertility: either azoospermia, severe oligozoospermia associated with hypogonadism and spermatogenic arrest or normal sperm counts associated with abnormal sperm morphology. Population II consisted of 200 unselected infertile patients. Population III consisted of 36 patients who had previously been shown to have aneuploidy, cytological deletions or translocations involving the Y-chromosome or normal karyotypes associated with severe phenotype abnormalities. Population IV consisted of 920 fertile (control) males. The deletion rates in populations I, II and III were 20.5%, 7% and 58.3%, respectively. A total of 92 patients with deletions were detected. The deletion rate in population IV was 0.87% involving 8 fertile individuals and 4 STSs which were avoided in multiplex panel construction. The ability of the nine multiplexes to detect pathology associated microdeletions is equal to or greater than screening protocols used in other studies. Furthermore, the data suggest a fourth AZF region between AZFb and AZFc, which we have termed AZFd. Patients with microdeletions restricted to AZFd may present with mild oligozoospermia or even normal sperm counts associated with abnormal sperm morphology. Though a definitive genotype/phenotype correlation does not exist, large deletions spanning multiple AZF regions or microdeletions restricted to AZFa usually result in patients with Sertoli Cell Only (SCO) or severe oligozoospermia, whereas microdeletions restricted to AZFb or AZFc can result in patients with phenotypes which range from SCO to moderate oligozoospermia. The panel of nine multiplexed reactions, the Y-deletion Detection System (YDDS), provides a fast, efficient and accurate method of assessing the integrity of the Y-chromosome. To date, this study provides the most extensive screening of a proven fertile male population in tandem with 514 infertile males, derived from three different patient selection protocols.

Worksite health promotion programs in the U.S.: factors associated with availability and participation.

PURPOSE: To examine how the availability of and participation in worksite health promotion programs varies as a function of individual (e.g., age), organizational (e.g., occupation), and health (e.g., high blood pressure) characteristics. Availability of worksite programs was also compared to that reported in two previous national surveys of private companies. DESIGN: Data analyzed were from the 1994 National Health Interview Survey (NHIS), a national cross-sectional probability sample of the U.S. civilian population. SUBJECTS: Five thousand two hundred nineteen NHIS respondents met the inclusion criteria of (1) being currently employed in a company of at least 50 employees, and (2) completing the NHIS section on worksite health promotion. MEASURES: Employees indicated the availability of, and their participation in, 33 different types of worksite programs. National Health Interview Survey data were also available regarding general health, blood pressure, body mass index, and medical conditions. RESULTS: Smoking cessation programs had the highest mean availability (43%), followed by health education programs (31%) and screening tests (31%). Overall, availability of worksite programs appeared comparable to that reported in a recent national survey. Participation ranged from 32% for health education programs to 5% for smoking cessation programs. Compared to availability, participation depended less on individual and organizational characteristics. Healthy employees were not consistently more likely to participate in worksite health promotion programs than nonhealthy employees. CONCLUSIONS: Although availability of worksite health promotion programs remains high, participation by employees in specific types of programs can vary widely. Attempts to increase participation should look beyond individual, health, and organizational variables, to specific features of the work environment that encourage involvement in health promotion activities.

Occupational differences in depression and global health: results from a national sample of US workers.

Occupational differences in depression and global health were examined in a sample of 8,486 employed persons who completed the 1987 National Medical Expenditure Survey (NMES). Scores on the depression and global health measures in the NMES were adjusted for age, race, sex, tenure, and hours worked per week, and then grouped according to occupations in the 1980 US Census code. In all, 239 different occupations, distributed across 11 occupational categories, were studied. Results indicated that professional and managerial occupations tended to have healthier scores on both depression and global health. Occupations involving the operation of machines or transportation equipment tended to have poorer scores. These findings are discussed in terms of factors that contribute to occupational differences in well-being, and the need for additional research in which more detailed information concerning working conditions is collected.

Neurobehavioral and health-related deficits in solvent-exposed painters.

The health status of 133 solvent-exposed painters was evaluated using the Neurobehavioral Evaluation System (NES) and blood test results from a physical exam. The comparison group consisted of 51 sheetmetal workers, minimally exposed to solvents. Degree of solvent exposure was calculated using three different indices derived from questionnaire responses. Multivariate analyses, adjusted for age, alcohol consumption, and smoking, indicated that painters performed less well on the symbol digit learning and vocabulary tasks. Evidence was also found for a dose-effect relationship, particularly when several features of the work environment were considered in estimating exposure. Degree of solvent exposure predicted levels of serum lead, BUN, and SGOT. These findings indicate that questionnaire-based measures of solvent exposure can be useful predictors of neurobehavioral and health-related deficits. Verbal ability, often used by researchers as a measure of premorbid functioning, may be adversely affected by solvent exposure.

Low dose versus medium dose UV-A1 treatment in severe atopic eczema.

Twenty-two patients with severe atopic eczema were included in a therapy study with UV-A1 (wavelengths > 340 nm) treatment. The patients were divided into two dose groups, each consisting of 11 patients. One group received 10 J/cm2 and the other 50 J/cm2 five times a week for 3 consecutive weeks. No topical or systemical steroids or antihistamines were allowed. Using the SCORAD index as a measure of disease activity before onset of therapy and after 10 and 15 treatments, we observed a significant improvement in both dose groups after 15 treatments (10 J/cm2: p < 0.05, 50 J/cm2: p < 0.005). After 10 treatments only the improvement in the 50 J/cm2 group was significant (p < 0.005); the difference between the two dose groups was significant (p < 0.05). The clinical efficacy of treatment was reflected neither by a decrease of serum IgE nor by a decrease of elevated serum levels of soluble adhesion molecules sICAM-1 and sELAM-1 in the two dose groups. In contrast, a marked but not significant decrease of serum ECP could be observed in the 50 J/cm2 group only. We conclude from these and other published data that although 10 J/cm2 UV-A1 has a limited effect on patients with severe atopic eczema, higher doses are of higher efficiency in the treatment of this condition.

Investigation of plasmid instability in amylase-producing B. subtilis using continuous culture.

Continuous culture was employed to study plasmid instability in an amylase-producing Bacillus subtilis 1A289 that was genetically manipulated. No true steady state could be obtained with 1A289(pEAA)-strain (plasmid)-due to its structural instability, which occurred both with glucose and Maltrin-100 as limiting carbon sources. The plasmid, pEAA (Cm(R), amy(+), i.e., chloramphenicol resistant, amylase positive) degenerated into a smaller plasmid, pEAA1 (CM(R), amy(-)) that was stable. There was a direct correlation between amylase-producing ability and this structural instability since f(amy) (fraction of cells with amylase-producing ability) reached zero at the same time that f (fraction of cells that are resistant to chloramphenicol) reached its maximum level. Since the deletion in pEAA was larger than the original amylase-gene insert, either all of part of the insert is absent from pEAA1. Though on discernible change in 1A289(pHV33), where pHV33 is the vector plasmid, was observed during continuous cultivation, its behavior was different from that of the stable 1A289(pEAA1).

Self-control in pigeons under the Mischel paradigm.

Walter Mischel studied self-control in preschool children in the following manner: if the child waited for an interval to end, he or she received the more preferred of two reinforcers; if the child responded to terminate the interval by ringing a bell, the less preferred reinforcer was given. We used an analogous procedure to study self-control in pigeons: if the bird waited for a trial to end, it received the more preferred reinforcer; if the bird terminated the trial by pecking a key, the less preferred reinforcer was given. We explored the effects on self-control of a number of variables analogous to those studied by Mischel and co-workers, e.g., presence versus absence of reinforcers, of alternative responses, and of stimuli during the wait interval; prior experience of the subjects; and test paradigm. The results obtained with pigeons paralleled the results obtained by Mischel with human children.

Isolation and characterization of a polynucleotide phosphorylase from Bacillus amyloliquefaciens.

Bacillus amyloliquefaciens BaM-2 produces large amounts of extracellular enzymes, and the synthesis of these proteins appears to be dependent upon abnormal ribonucleic acid metabolism. A polynucleotide phosphorylase (nucleoside diphosphate:polynucleotide nucleotidyl transferase) was identified, purified, and characterized from this strain. The purification scheme involved cell disruption, phase partitioning, differential (NH4)2SO4 solubilities, agarose gel filtration, and diethylaminoethyl-Sephadex chromatography. The purified enzyme demonstrated the reactions characteristic of polynucleotide phosphorylase: polymerization, phosphorolysis, and inorganic phosphate exchange with the beta-phosphate of a nucleotide diphosphate. The enzyme was apparently primer independent and required a divalent cation. The reactions for the synthesis of the homopolyribonucleotides, (A)n and (G)n, were optimized with respect to pH and divalent cation concentration. The enzyme is sensitive to inhibition by phosphate ion and heparin and is partially inhibited by rifamycin SV and synthetic polynucleotides.

Inhibition of vesicular stomatitis virus replication by poly(2'-fluoro-2'-deoxyuridylic acid).

Poly(2'-fluoro-2'-deoxyuridylic acid) is known to be an effective inhibitor of the deoxyribonucleic acid polymerase found within the oncornaviruses. This synthetic polynucleotide was found to inhibit the replication of vesicular stomatitis virus in mouse L cells. The polymer was shown to be capable of inhibiting the viral ribonucleic acid (RNA)-dependent RNA polymerase, and it is proposed that this is the mechanism of antiviral activity. The following observations support this viewpoint: (i) the polymer is most active when added after virus adsorption; (ii) the antiviral activity is not species specific; and (iii) the polynucleotide is nontoxic to the host cell. Conventional methodologies designed to increase nucleic acid uptake by cultured cells do not show an increase in antiviral potency.