Behavioral determinants of occupational exposure to chemical agents.

Used the passive-active dimension of the job demand–control model (T. Theorell and R. A. Karasek, see record 83:28881) to examine the impact of behavioral factors on the exposure to and actual uptake of airborne lead in 2 lead exposed populations of male workers (18 from an electric accumulator factors and 18 from a lead smeltery) and to ascertain work-related determinants of hygienic behavior. Environmental exposure was assessed by measurement of the concentration of lead dust in ambient air at the workplace, and the intake of lead was assessed by measurement of the lead in blood level. In the work environment of Ss in active jobs, lower concentrations of lead in air were measures, but higher levels of lead in blood were observed in these workers. The opposite was true of workers in passive jobs. Differences in hygienic behavior (e.g., use of protective equipment) at work may explain these results. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of the use of the Vocational Exploration Group on career maturity.

60 8th- and 9th-grade students, 36 males and 24 females, were randomly assigned to experimental groups participating in the Vocational Exploration Group (VEG) process for 1 hr/wk for 5 wks and to a control group receiving no career education, to determine if VEG treatment applied to rural junior high students would result in increased career maturity. The Career Maturity Inventory, which was administered to all Ss before and after the treatment, indicated significantly positive changes for the experimental groups on the Attitude scale and on 3 of the 5 Competence scales, while scores for the control group remained constant. Results indicate that the VEG can effectively assist students to develop positive attitudes toward the world of work and to acquire critical behavior upon which to base mature career decisions. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of parents' job insecurity on children's work beliefs and attitudes.

The authors hypothesized that children's perceptions of their parents' job insecurity mediate the effects of parental job insecurity and layoffs on children's work beliefs and work attitudes. Male and female undergraduate students (N?=?134; M age?=?18.9 years), as well as their mothers (M age?=?47.0 years) and fathers (M age = 49.1 years), participated voluntarily. With structural equation modeling as implemented by LISREL VIII, support for the proposed model was obtained, whereas no support was obtained for a competing model. Moreover, identification with fathers moderated the influence of perceived paternal job insecurity on children's humanistic work beliefs, but no comparable effect emerged for mothers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of exposure to hypoxia on the signal-averaged electrocardiogram in healthy subjects

The effects of hypoxia on the signal-averaged ECG (SAECG) were investigated in 26 healthy active subjects with no suggestion of cardiac disease. The SAECG was recorded in each resting subject in normoxic and hypoxic normobaric conditions (inspired O2 fraction 20.7 vs 10.0%) which lowered resting arterial O2 saturation from 98.6 +/- 0.6% to 77.7 +/- 8%. Recordings from four subjects (three men) met the definition of abnormal late potentials at baseline; in all these subjects but one, who exhibited an improved but still abnormal QRS duration, these parameters returned to normal in hypoxic conditions. The duration of the filtered QRS was significantly reduced (from 107.6 +/- 13.2 to 101.6 +/- 11.3 ms, P < 0.01), the duration of the low amplitude signals in the terminal portion of the QRS < 40 microV (LAS) significantly decreased (from 26.5 +/- 9.5 to 22.7 +/- 7.9 ms, P < 0.05) and the root mean square voltage in the last 40 ms (Term-RMS) increased non-significantly (from 55.8 +/- 40.2 to 69.1 +/- 38.3 microV, P = 0.058). Hypoxia determined a higher (P < 0.05) heart rate increase in subjects with abnormal records than in normal subjects. These data could be related to a sympathic discharge. They suggest that: (1) variation in heart rate could affect the SAECG; (2) exposure to hypoxia improves SAECG parameters in healthy subjects, possibly related to sympathetic discharge; (3) abnormal records collected during sinus bradycardia could represent a type of false-positive expression of late potentials in young active adults.     

Effects of repeated heat exposure on hypothalamic sensitivity to norepinephrine

Bilateral stainless steel guide tubes were stereotaxically implanted above the anterior hypothalamus (AH) of 12 male Sprague-Dawley rats (300-360 g). Beginning 3 days postsurgery, norepinephrine (NE) was injected into the AH each day at increasing depths below the guide tube until colonic temperature fell at least 0.8 degrees C. Subsequently, the effects of treadmill exercise at 21.5 m/min for 3 wk at 22 degrees C (n = 6) or 35 degrees C (n = 6) on the magnitude of the NE-induced hypothermia were investigated. Training duration ranged from 12 to 50 min/day, depending on the time required for colonic temperature of the heated rats to rise to a predetermined level: 40.4 degrees C on day 1, increasing 0.1 degree C/day to 41.5 degrees C on day 12 and thereafter. Before and after training, bilateral injections of NE (10 micrograms) at 22 degrees C at rest and just before exercise (21.5 m/min) caused the following mean +/- SE reductions in colonic temperature (degree C). (Formula: See Text). These reductions in colonic temperature were associated with sharp elevations in tail-skin temperature, but there were no significant differences in the response between the two groups. We conclude that repeated heat exposure increased the sensitivity of the AH to exogenous NE.     

Effects of different protective agents on the phototoxicity of fluoranthene to Daphnia magna

OBJECTIVE: To determine if a risk prediction model for patients with unstable angina would predict resource utilization. METHODS AND RESULTS: Four hundred sixty-five consecutive patients admitted for unstable angina to a tertiary care university-based medical center were prospectively evaluated from June 1, 1992, to June 30, 1995. The proportion of patients receiving coronary angiography, coronary angioplasty, and coronary artery bypass grafting were analyzed according to four risk groups on the basis of a previously published model: Group 1, <2% risk of major complication; Group 2, 2.1% to 5% risk; Group 3, 5.1 % to 15% risk; and Group 4, >15.1 % risk. Hospital length of stay and estimated cost of hospitalization based on DRG and specific payer ratio of cost-to-charge were also compared between groups. Multiple linear regression analysis was used to determine the influence of estimated risk and procedures on hospital costs. The four groups were well matched for gender, hypertension, tobacco history, and previous percutaneous transluminal coronary angioplasty and myocardial infarction. Group 4 had a higher incidence of previous coronary bypass grafting (35% vs 10%, p=0.001) and triple vessel or left main coronary artery disease compared with Group 1 (44% vs 13%, p=0.041). Group 4 patients were more likely to be admitted to the coronary care unit compared with Group 2 or Group 1 patients (80% vs Group 1: 51% [p= 0.001]; and vs Group 2: 53% [p=0.001]), more likely to receive heparin (87% vs 71%, p=0.007), and more likely to receive a beta-blocker or calcium channel blocker (89% vs 74%, p=0.008) than Group 1. Coronary angioplasty rates were similar for all groups, but Group 4 patients were more likely to receive coronary bypass grafting than Group 2 or Group 1 (27% vs Group 2: 12%, p=0.004 and vs Group 1: 8%, p=0.002). Hospital length of stay was highest in Group 4 and lowest for Group 1. Average hospital costs were significantly less in Group 3 than in Group 4, but higher than in Group 1. Multivariate analysis determined a dependency of costs on risk group with Group 2 having costs 31.4% (95% CI=9.8 to 57.2), Group 3 46.7% (24, 3 to 73.1), and Group 4 75% (46.9 to 110.7) higher than Group 1. The use of procedures also significantly increased costs, with PTCA-treated patients having a 44.9% (26.7 to 65.7) increase in costs compared with medically treated patients, and surgically treated patients having a 204.7% increase in costs. CONCLUSION: Resource utilization as assessed by the use of revascularization procedures, length of stay, and hospital costs are influenced by patient acuity estimated from a prediction model on the basis of estimated risk of cardiac complications. The model exerts independent influence on cost even after adjustment for various procedures. The use of revascularization procedures, especially coronary artery surgery, remains a large determinant of hospital cost.     

Oxygen toxicity in the newborn. The effect of chronic continuous 100 percent oxygen exposure on the lungs of newborn mice

Continuous exposure of newborn mice of a single, highly inbred strain to 100% oxygen at normal atmospheric pressure for up to 6 weeks resulted in a progressive evolution of pulmonary changes which consisted of dense fibrous tissue deposition, chronic bronchitis and bronchiolitis, and emphysema. Survival of the experimental animals decreased with the duration of exposure, and it was 18% after the sixth week. While the pulmonary changes were evolving, lung growth was markedly inhibited in the experimental animals, whereas lung weight increased significantly. The present study indicates that in contrast to the adult mouse, survival of a substantial percentage of newborn mice for at least 6 weeks is possible, but it is associated with severe changes in pulmonary structure that doubtlessly lead to serious derangement of cardiopulmonary functions.     

Biomonitoring of possible human exposure to environmental genotoxic chemicals: lessons from a study following the wreck of the oil tanker Braer

In January 1993 the oil tanker Braer ran aground in the Shetland Islands, Scotland. Approximately 80,000 tons of crude oil were released. Exceptionally high winds caused extensive pollution and exposure of the local population to crude oil. We describe the study which was immediately set in place to examine the exposed population for evidence of genotoxic exposure. Blood samples were taken and primary DNA damage was measured in the mononuclear cell fraction by the butanol modification of the 32P-postlabelling method. Mutation was measured at the hprt locus in T lymphocytes. No evidence of genotoxicity was obtained for either end point, but nevertheless, we believe that useful lessons were learnt, which should be incorporated into the design of future studies: (1) A rapid response is essential, and even if sufficient funds are not immediately available, it is still worth attempting to obtain samples quickly and use cryopreservation, also to attempt to estimate exposure. (2) Adequate numbers of volunteers must be sought, together with enough controls, not just to allow meaningful analysis but to overcome loss of samples and failure of things to go according to plan. (3) Points concerning laboratory practice include: (i) samples should be coded, (ii) clearly defined and proven protocols should be used, (iii) irreplaceable samples should not be used for method development, (iv) should a problem become apparent during the study, work on such samples should cease immediately until the problem is solved, (v) all critical experimental components should be pretested against a laboratory standard. (4) The study design should include replicate experiments to monitor experimental variability and reproducibility, as well as internal standards and cryopreserved "in house" samples. Care must be taken that samples from any one exposure group are spread between a number of independent experiments and that each experiment includes samples from a number of exposure groups. (5) A computerised data base should be maintained with full details of experimental variables, donor attributes, and raw data so that any contribution of experimental artefacts to "outlier" results can be monitored. (6) Because of the nature of the statistical variation for many environmental genotoxicity end points, only a large-scale study is likely to be capable of yielding useful information.     

Studies on maturity in newborn infants. IX. Further observations on the use of external characteristics in estimating gestational age

A simple method for assessing maturity based on 8 external characteristics has previously been described. Some new results with the use of this method are now presented. The precision in estimating gestational age is sufficiently good, more than 95% of the infants were correctly estimated within +/- 3 weeks. Reducing the criteria to seven and thereby excluding the ophthalmoscopic examination did not significantly change the precision of the estimation. The examination based on external characteristics is a very simple and useful method for maturity assessment, even in sick newborn infants. Tables for transforming maturity score into gestational age are presented.     

Effects of parents' experiential avoidance and PTSD on adolescent disaster-related posttraumatic stress symptomatology.

Despite the importance of family context to adolescents' reactions following disaster, little research has examined the role of parents' functioning on adolescents' disaster-related posttraumatic stress disorder (PTSD) symptoms. Using data from 288 adolescents (ages 12 to 19 years) and 288 parents exposed to a series of severe tornadoes in a rural Midwestern community, this study tested a conceptual model of the interrelationships between individual and parental risk factors on adolescents' disaster-related PTSD symptoms using structural equation modeling. Results showed that the psychological process of experiential avoidance mediated the relationship between family disaster exposure and PTSD for both adolescents and their parents. Parents' PTSD symptoms independently predicted adolescents' PTSD symptoms. Further, parents' postdisaster functioning amplified the effects of adolescent experiential avoidance on adolescents' disaster-related PTSD symptoms. Findings highlight the importance of family context in understanding adolescents' postdisaster reactions. Clinical implications are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Perinatal nicotine exposure impairs ability of newborn rats to autoresuscitate from apnea during hypoxia

Failure to autoresuscitate by hypoxic gasping during prolonged sleep apnea has been suggested to play a role in sudden infant death. Furthermore, maternal smoking has been repeatedly shown to be a risk factor for sudden infant death. The present experiments were carried out on newborn rat pups to investigate the influence of perinatal exposure to nicotine (the primary pharmacological and addictive agent in tobacco) on their time to last gasp during a single hypoxic exposure and on their ability to autoresuscitate during repeated exposure to hypoxia. Pregnant rats received either nicotine (6 mg. kg-1. 24 h-1) or vehicle continuously from day 6 of gestation to days 5 or 6 postpartum via an osmotic minipump. On days 5 or 6 postpartum, pups were exposed either to a single period of hypoxia (97% N2-3% CO2) and their time to last gasp was determined, or they were exposed repeatedly to hypoxia and their ability to autoresuscitate from primary apnea was determined. Perinatal exposure to nicotine did not alter the time to last gasp, but it did impair the ability of pups to autoresuscitate from primary apnea. After vehicle, the pups were able to autoresuscitate from 18 +/- 1 (SD) periods of hypoxia, whereas, after nicotine, the pups were able to autoresuscitate from only 12 +/- 2 periods (P < 0.001) of hypoxia. Thus our data provide evidence that perinatal exposure to nicotine impairs the ability of newborn rats to autoresuscitate from primary apnea during repeated exposure to hypoxia, such as may occur during episodes of prolonged sleep apnea.     

Human exposure to a granulocytic Ehrlichia and other tick-borne agents in Connecticut

Indirect fluorescent-antibody (IFA) staining methods with Ehrlichia equi (MRK or BDS strains) and Western blot analyses containing a human granulocytic ehrlichiosis (HGE) agent (NCH-1 strain) were used to confirm probable human cases of infection in Connecticut during 1995 and 1996. Also included were other tests for Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis (HME), Babesia microti, and Borrelia burgdorferi. Thirty-three (8.8%) of 375 patients who had fever accompanied by marked leukopenia or thrombocytopenia were serologically confirmed as having HGE. Western blot analyses of a subset of positive sera confirmed the results of the IFA staining methods for 15 (78.9%) of 19 seropositive specimens obtained from different persons. There was frequent detection of antibodies to a 44-kDa protein of the HGE agent. Serologic testing also revealed possible cases of Lyme borreliosis (n = 142), babesiosis (n = 41), and HME (n = 21). Forty-seven (26.1%) of 180 patients had antibodies to two or more tick-borne agents. Therefore, when one of these diseases is clinically suspected or diagnosed, clinicians should consider the possibility of other current or past tick-borne infections.     

Immune system dysfunction during exposure to poult enteritis and mortality syndrome agents

Poult Enteritis and Mortality Syndrome (PEMS) is a condition of yet undefined etiology. Affected flocks may exhibit 100% morbidity with mortality up to 50% or more between 2 to 4 wk of age. The current study reports the immune status of poults experimentally infected with PEMS agent(s) in various trials. When compared with the unchallenged controls, PEMS-infected poults had significant atrophy of the bursa (up to 2-fold), thymus (up to 11-fold), and spleen (up to 2-fold) (P < or = 0.05). When challenged with SRBC, PEMS-infected poults had 1 to 2 log2 lower anti-SRBC antibody titers than the controls (P < or = 0.05). Responsiveness to a mitogenic lectin, phytohemagglutinin-P, was reduced significantly in PEMS poults (P < or = 0.05). These data show that the immune system of the poults is compromised significantly during PEMS infection in terms of lymphoid organ integrity and humoral and cell-mediated immunity. These findings imply, therefore, that immune dysfunction may contribute to the mortality observed during PEMS outbreaks.     

Adhesion of oral Candida albicans isolates to denture acrylic following limited exposure to antifungal agents

Candidal adherence to denture acrylic surfaces is implicated as the first step in the pathogenesis of Candida-associated denture stomatitis, the most prevalent form of oral candidosis in the West. This condition is treated by topically administered antifungal agents, mainly belonging to the polyenes and azoles. As the intraoral concentrations of antifungals fluctuate considerably due to the dynamics of the oral environment, the effect of short exposure to sublethal concentrations of antifungals on the adhesion of Candida albicans to denture acrylic surfaces was investigated. Seven oral C. albicans isolates were exposed to four-eight times minimum inhibitory concentrations (MIC) of five antifungal drugs, nystatin, amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole, for 1 h. After removing the drug (by repeated washing) the adhesion of these isolates to acrylic strips was assessed by an in vitro adhesion assay. Exposure to antifungal agents significantly reduced the adherence of all seven C. albicans isolates to denture acrylic. The mean percentage reductions of adhesion after limited exposure to nystatin, amphotericin B, 5-fluorocytosine, ketoconazole and fluconazole were 86.48, 90.85, 66.72, 65.88 and 47.42%, respectively. These findings indicate that subtherapeutic doses of antifungals may modulate oral candidal colonization. Further, these results may have an important bearing on dosage regimens currently employed in treating oral candidosis.     

硫化剂对CPE粘结磁体性能的影响

针对高填充率的氯化聚乙烯(CPE)粘结磁体，提供几种常用的硫化体系．通过分析硫化体系的硫化特性，找出不同的硫化体系对磁体性能的影响．     

Effects of postassault exposure to attack-similar stimuli on long-term recovery of victims.

Recent studies have suggested a classical conditioning explanation for the "core of distress" symptom reported by rape victims that reportedly persists well after most other symptoms have subsided. The current study tested an extension of this theory to the long-term reactions of victims of domestic assault and nondomestic assault in addition to victims of rape. Level of long-term psychological distress was found to be strongly related to level of victim exposure to stimuli in the absence of a subsequent attack; long-term distress level was found to be unrelated to short-term distress level when controlling for level of exposure to attack-similar stimuli. Results suggest the tenability of a classical conditioning model of long-term psychological distress experienced by victims of the types of assault studied, thus highlighting the importance of situational variables in the recovery process. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)