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PubMed2005

Nonagricultural and residential exposures to pesticides.

Epidemiologic studies and risk assessments conducted to assess the chronic effects of pesticides are limited by inadequate measurements of pesticide exposures, and surrogates for these data are frequently used. In this paper, pesticide use and absorbed dose previously measured in residential and occupational settings are used to evaluate the hypothesis that there is a relationship between pesticide use and exposure. For homeowner applicators of 2,4-dichlorophenoxyacetic acid (2,4-D) and chlorpyrifos, exposures were poorly correlated with the amount of herbicide used (r2 = 0.01 to 0.40); however, exposures from a granular product were consistently less than those with liquid formulation. For professional landscape applicators, exposure over 14 days and 7 days of use was poorly correlated with the amount of 2,4-D sprayed (r2 = 0.17 and 0.21, respectively). However, inclusion of the type of spray nozzle used and the use of gloves while spraying in the model explained increased predictability and explained 68% of the variation.

Attitude to Health↗

PubMed1992

[Gene organization of HLA and its association with ocular disease].

It is now evident that the human major histocompatibility complex (MHC), human leucocyte-associated antigen (HLA), regulates the immune response through discrimination between autologous and non autologous substances thereby displaying a high degree of genetic polymorphism. In recent years, the three-dimensional structure of HLA has been clarified by crystal analysis and provides the attractive hypothesis, the so-called hotdog model, explaining the interactions of foreign antigens (or autologous antigens), HLA and T cell receptors and has a great impact on various studies on immunogenetic mechanisms underlying the development of many diseases. Thus, several HLA-associated ocular diseases such as Behçet's disease and Harada's disease have also been analyzed from this point of view by means of recombinant DNA techniques, enabling elucidation of molecular mechanisms of susceptibility to these diseases. This paper describes a general outline of HLA, especially its genetical structure, as well as recent analysis of molecular mechanisms of the predisposition to representative ocular diseases.

Eye Diseases↗

PubMed2005

[Development of internet addiction measurement scales and Korean internet addiction index].

OBJECTIVES: To develop measurement scales of Internet addiction, and propose a Korean Internet Addiction Index (K-IAI) and classification criteria for Internet addiction from the threshold scores developed. METHODS: The identification of the concept of "Internet addiction" was based on the literature review. To select the scales, an exploratory factor analysis was applied. A construct validation was tested by a confirmatory factor analysis (CFA) with a structured equation model (SEM). In testing the validity of the classification criteria, ANOVA and non-recursive models with SEM were applied. RESULTS: Out of 1,080 questionnaires distributed, 1,037 were returned,; a response rate of 96%. The Cronbach-alpha of all items was over 0.75. Using an exploratory factor analysis in the condition of a 6 factor constrain as the study model proposed, 23 of the initial 28 items were identified. In testing the discriminant and convergent validity of the selected 23 scales using CFA with SEM, the Internet addiction model explained about 93% of all variances of the data collected, and all the latent variables significantly explained the designated scales. A K-IAI was proposed using the T-scores of the sum of all factor averages. In the classification of users, the basic concept was a two-standard deviation approach of the K-IAI as the criteria of MMPI. The addiction group had a score > or =70 in the K-IAI, the pre-addiction group between > or =50 and <70, and the average user group <50. The Internet use times of the classified groups were statistically different in the ANOVA and multiple comparisons. CONCLUSIONS: The K-IAI is a reliable and valid instrument for measuring Internet addiction. Moreover, the taxonomy of the groups was also verified using various methods.

Behavior, Addictive↗

PubMed2005

Factors contributing to the variation in oral hygiene practices and facilities in long-term care institutions for the elderly.

OBJECTIVE: This study was designed to explore variations in oral hygiene practices and facilities in long-term care institutions for elders. Reported level of caregivers' knowledge related to oral health, reported work-climate, management, size of the institution and the mean age and degree of dependency of residents were evaluated. METHODS: Sixteen nursing homes were selected, using stratified random sampling, in the region of Gent (Flanders). Nine different strata were used based on size and management. Factors thought to be associated with the variation in oral hygiene practices and facilities were collected from 225 caregivers (75%) through a structured 45-item questionnaire. The questionnaire was validated and tested for reliability during a test-retest prior to the start of the study. The relation between rates of oral hygiene practices and facilities and explanatory variables was investigated using correlation analysis and subsequently by multiple regression analysis. RESULTS: The best fitted regression model explained 30% of oral hygiene practice variation. The most predictive variable was the knowledge of caregivers, which explained 17% of the variation, while mean age explained 7% and managerial behaviour 6.3%. There was a trend towards a negative relationship with mean age, degree of dependency and size of the institution. CONCLUSION: Most of the variance in oral health practices and facilities in long-term care institutions for elders in Gent remains unexplained. Knowledge, mean age and managerial behaviour were the most likely explanatory variables.

Age Factors↗

PubMed2006

[The effect of perceived work and organizational chracteristics on psychological distress and intention to quit of information technology professionals].

PURPOSE: The information technology (IT) and service industry in Japan is known to have many work-related stressors, and requires more effective stress reduction to control an elevated turnover rate and adverse health effects. However, little research has been performed using either individual or organizational outcomes (e.g., psychological distress and intention to quit) to determine micro and macro-level stressors on information technology (IT) professionals. This study aimed to examine the effect of perceived work and organizational characteristics (PWOC) as micro and macro-level stressors on psychological distress and intention to quit, controlling for profitability of the organization and individual characteristics on IT professionals in Japan. METHODS: We conducted a web-based questionnaire at fifty-three Japanese IT-related companies. From May to June of 2003, ten to thirty people from each company, who were chosen according to quota method indicators through the labor unions, voluntarily participated in this study. Participants accessed our webpage, which was designed with a self-administrated questionnaire and was accessible by password. The data they entered were sent to our database automatically. The questionnaire consisted of items concerning socio-demographic status; office size; employment characteristics; work hour characteristics; profitability of the organization; a novel 29-item scale (PWOC); as well as individual characteristics. The response rate was 66% (n = 1049). For the purpose of this study, we analyzed data on an IT engineers' group separately (n = 871). RESULTS: Hierarchical multiple regression analysis showed that each model explained 23% and 26% of the variance in psychological distress and intention to quit, respectively. PWOC sub-scales, which are related to macro-level stressors (e.g., undeveloped management systems and career and future ambiguity), affect not only psychological distress but also intention to quit. Objective data of macro-level stressors such as increased profitability determine intention to quit, independently controlling for their PWOC. Also, growth need strength was an important personal characteristic for psychological distress. The results allow us to speculate on macro as well as micro-level stressors for ways that organizations might reduce IT professionals' stress and increase their productivity. CONCLUSIONS: This study suggests that macro-level stressors are important factors for psychological distress and intention to quit for IT professionals, as well as micro-level stressors. Since occupational stress is costly in terms of organizational outcomes, further research on occupational stress measuring individual and organizational outcomes both within and beyond the Japanese IT industry should prove useful.

Computers↗

PubMedDate not supplied

[Minimal brain dysfunction in adolescents (clinical study)].

Description of the adolescent minimal brain dysfunction (M.B.D.) syndrome (DSM III, Attention deficit disorder, residual type), not easily recognised during adolescence, because the symptomatology of the child hyperkinetic syndrome becomes chiefly social and manifests itself within relationships. But the attention disorders remain. The whole stresses the psychological features of the adolescent: lowering of self-esteem, powerless feelings, paranoid defences, identity, autonomy and authority problems, higher frequency of delinquent behaviour. Biochemical aspects are briefly discussed. The author describes a psychopathological explaining model which allows the understanding of the behavioural symptoms and shows that a same structure underlies the child hyperkinetic syndrome and the M.B.D. syndrome of the adolescent. The M.B.D. is not to be considered as a disease but rather as a psychic handicap in the domains of the intellect, action and affect, which psychosocial expression is determined by the importance of the disorder, the environment, the intelligence quotient, the tolerance of the relative and peers, and the personal history. Three cases are reported.

Adolescent↗

PubMed1991

Ventilatory lung function in young cigarette smokers: a study of susceptibility.

The objective of this study was to estimate the effect of cigarette smoking on ventilatory lung function among young adults with special emphasis on the recognition of susceptible subgroups. In a cross-sectional study of 1,044 adults aged 15-40 yrs, a statistically significant linear relationship between quantity of smoking in cigarette-years and level of forced expiratory volume in one second (FEV1) was found. Among current cigarette smokers, FEV1 level was on average 35 ml lower for each 100 cigarette-years of exposure (corresponding to smoking of ten cigarettes per day for 10 yrs) compared to lifelong nonsmokers in a linear regression adjusted for confounding. Potentially susceptible subgroups were studied by introducing interaction terms between quantitative smoking and gender, wheezing, atopy, asthma, childhood respiratory illness and exposure to environmental tobacco smoke during the growth period, to the additive linear regression model explaining the FEV1 level. Wheezing was found to modify the effect of smoking significantly: the FEV1 level was on average 68 ml lower for each 100 cigarette-years due to interaction between smoking and wheezing. An introduction of the interaction term eliminated the independent effect of smoking. The results suggest that the detrimental effect of smoking on FEV1 in young adults may be limited to individuals with wheezing. Thus, the presence of wheezing among smokers indicates a higher risk for low level of ventilatory lung function compared to smokers who do not wheeze.

Adolescent↗

PubMed1991

N-acetyl-beta-D-glucosaminidase as a predictor of milk loss and recovery after clinical mastitis.

Milk samples were collected at onset of 508 episodes of clinical mastitis on a 1,700-cow dairy farm in Michigan. Daily milk production and disease events were recorded for all cows in the herd. Despite statistical association with severity of mastitis, this association was too weak for N-acetyl-beta-D-glucosaminidase (NAGase) activity to be of great value as a prognostic test for clinical mastitis. High milk NAGase activity was significantly (P less than 0.0001) associated with: increased duration of treatment; increased duration of clinical signs of mastitis; decreased daily milk production; and increased risk of the cow being culled because of mastitis. The NAGase value was combined with days in milk production, baseline milk production before mastitis onset, parity, and season of onset to predict the outcome of clinical cases as measured by the first 3 aforementioned variables. Statistical models explained little of the variability among cows in duration of treatment (R2 = 0.11), duration of clinical signs of infection (R2 = 0.11), and milk production change (R2 = 0.09).

Acetylglucosaminidase↗

PubMed1991

Ascorbic acid enhances the effects of 6-hydroxydopamine and H2O2 on iron-dependent DNA strand breaks and related processes in the neuroblastoma cell line SK-N-SH.

Neuroblastoma cells accumulate ascorbic acid and iron. It was hypothesized that these features could be exploited for sensitizing neuroblastoma cells for therapy in combination with reactive oxygen intermediates. In the present study the effects of 6-hydroxydopamine (6-OHDA) and H2O2 on metabolic parameters critical for cell survival were investigated in cells with low and high ferritin content in the presence and absence of ascorbate. Human neuroblastoma SK-N-SH cells were pretreated with 100 microM FeSO4 and 10 microM desferrioxamine, respectively, for 24 h yielding cells with different ferritin contents. The effects of 6-OHDA and H2O2 (25 microM-250 microM) in the absence and presence of 1 mM ascorbic acid on DNA strand break formation, activation of poly(ADP-ribose) polymerase, and finally decrease in NAD+ and ATP concentration were investigated. All these parameters were influenced by 6-OHDA and H2O2 in a concentration-dependent manner in a similar way. The effects were most pronounced in ferritin-rich cells and in the presence of ascorbic acid. Using isolated CCC PM2 DNA, 6-OHDA and ascorbic acid caused strand breaks that were prevented in the presence of mannitol or desferrithiocine. H2O2-mediated strand breaks were observed only in the presence of ascorbic acid. Based on these data and data published by others a model explaining the deleterious effects of ascorbic acid on neuroblastoma cells is presented. It is suggested that continuous application of a high dosage of ascorbic acid might be a useful approach in neuroblastoma therapy.

Adenosine Triphosphate↗

PubMedDate not supplied

15-hydroxyeicosatetraenoic acid synthesis from exogenous arachidonate by bronchial mucosa.

Arachidonate metabolism in bronchial mucosa was investigated. Bronchial biopsies from four asthmatics and three non-asthmatic controls were challenged with 300, 465, 650 and 960 mOsm/kg saline in the presence of [3H]arachidonate. Supernatants were analysed by reverse-phase high-performance liquid chromatography. The major arachidonate metabolite was identified as 15-monohydroxyeicosatetraenoic acid (15-HETE), with significantly higher production in biopsies from asthmatics than controls. Statistical analysis of the full model explained 81% of the variation (F = 14.8; df = 6, 21; P less than 0.001). Hyperosmolarity and the presence of sarcoid had no significant effect on 15-HETE synthesis, reducing R2 by only 6%.

Adult↗

PubMed1990

Return to work after stroke: development of a predictive model.

Seventy-nine stroke patients who underwent a vocationally oriented, comprehensive, inpatient stroke rehabilitation program were followed up to evaluate their return to work. At follow-up, 49% had returned to work a mean of 3.1 months after rehabilitation discharge. Factors associated with success and with failure of vocational rehabilitation were then identified, and a predictive model was developed. There were positive associations between return to work and Barthel Index on admission (p = 0.0002) and discharge (p = 0.0015). Negative associations were found between return to work and aphasia (p = 0.0009), rehabilitation length of stay (p less than 0.0001), and prior alcohol consumption (p = 0.03). A step-wise multiple regression model explained 42% of the variance in return to work. Those most likely to return to work were not aphasic; they had shorter rehabilitation lengths of stay and higher Barthel Index scores on discharge; and they were lighter consumers of alcoholic beverages before their strokes. In conclusion, a set of factors predictive of return to work in younger stroke patients was identified, including, most notably, a strong negative association with aphasia and an intriguing negative association with prior alcohol consumption.

Adult↗

PubMed1990

Neutralization and delinquency: a comparison by sex and ethnicity.

A path model illustrating the relationships between church attendance, delinquent peer association, tendency to neutralize delinquency, and self-reported delinquent behavior was compared between males and females and between Mexican-American and Anglo college students (N = 694). The structure of the relationships among these variables was found to be similar across all four subsamples, although there was some variation in the strength of the relationships. In all four subsamples, the strongest paths were between neutralization and delinquent behavior, especially among Anglos and among males, and the weakest paths were between church attendance and delinquent behavior. On the other hand, church attendance was more strongly related to having fewer delinquent peers among Anglos and females. The path models explained substantial amounts of variation in delinquent behavior: 38% among Anglos, 32% among females, 31% among males, and 30% among Mexican-Americans.

Adaptation, Psychological↗

PubMed1990

Functional morphology of the hindlimb in some lacertilia.

Based on a global exploration of the hindlimb in some lacertilian species, an equally global functional approach has been undertaken, which led to the concept of the crural mechanism, an integral mechanism comprising the knee joint and the joints between respectively tibia and fibula on the one hand and the astragalocalcaneum on the other. Simple models explain the position of muscles and ligaments in relation to the homonymous rotation of tibia and fibula as well as the relative anterior displacement of fibula in front of the tibia. The linkage of knee and ankle joints appears to be based on those morphological features in both proximal and distal joints, that preclude pure axial rotations of tibia and fibula without deviation of these bones, again in both knee and ankle. The final result appears to be an integral mechanism endowed with one degree of freedom. An attempt has been made to identify the significance of the crural mechanism for function of the hindlimb in sprawling gait.

Animals↗

PubMed1989

Molecular mechanisms of defense against oxygen lack.

Evidence has been accumulating over the last several years suggesting that suppression of oxidative metabolism without concomitant glycolytic activation and the maintenance of cell membrane electrochemical gradients are central and minimal provisions for protecting tissues against oxygen lack. This evidence for diving vertebrates is reviewed and evaluated. It is concluded that the model explains long-term anoxia and hypoxia tolerance of aquatic lower vertebrates. Whereas this strategy, which is dominated by metabolic suppression capacities, may also be utilized by large, long-duration divers such as Weddell seals, it is unlikely to play a significant role in smaller and faster swimming marine mammals, where the energy demands of exercise greatly exceed the energy savings achievable by switching down metabolic rates of hypoperfused tissues.

Adenosine Triphosphatases↗

PubMedDate not supplied

[Comparative analysis of sequences of protein D2 from photosystem 2 reaction center and various Ca 2+-binding proteins].

The amino acid sequence of D2 protein was compared with those of calcium binding proteins and receptor for calcium channel blockers in connection with the data showing the participation of Ca2+ in photosystem 2 electron transport and the inhibition of this process by calmodulin antagonists, calcium channel blockers and local anesthetics. Protein D2 possesses a pattern analogous to the "EF-hand" sites of the calcium binding proteins. Comparison of the amino acid sequence of the calmodulin fragment binding the phenothiazine type calmodulin antagonists with the amino acid sequence of D2 protein and calcium channel protein revealed a high degree of sequence identity. Common structural features take place also between the membrane spanning segment III of D2 protein, which contains the tyrosine residue (161), responsible for ESR-signal IIS, and the membrane segment IVS5 of calcium channel protein. A model explaining the mechanism of calcium function in the oxygen-evolving system is proposed.

Amino Acid Sequence↗

PubMed1989

Clinical features of a neuropathologically verified familial Alzheimer's cohort with onset in the fourth decade: comparison with senile onset Alzheimer's disease and etiopathogenic implications.

Clinical and pathologic features of a family with early onset, autosomal dominant, familial Alzheimer's disease (AD) are compared and contrasted with senile onset dementia of the Alzheimer type. Late onset AD has previously been observed to have a characteristic progression and clinical course. A previously unreported pedigree, with two siblings and their father affected, of early clinical onset is presented. Molecular genetic study of this family using in situ chromosome hybridization showed an apparent marker on chromosome 9. This early onset form of AD is observed to be clinically consistent with the common late onset form of AD, but follows a more rapid course. An etiopathogenic model explaining the early onset, and other forms of AD is presented.

Adult↗

PubMed1989

Factors associated with hospital-specific cesarean birth rates.

The variation in hospital-specific cesarean birth rates was examined using a multiple regression analysis in a national data base of deliveries in 1977. This data base included 222,285 singleton births in 282 hospitals representing all regions of the United States. The 32 independent variables included measures of medical risk, technologic sophistication, demographic characteristics and economic incentives. The incidences of medical risk factors, nonwhite race and ratio of obstetricians to fertile women were associated positively with hospital-specific cesarean delivery rates. Participation in health maintenance organizations and numbers of deliveries were correlated negatively with those rates. Hospital-specific cesarean delivery rates were not associated with technologic sophistication, malpractice premiums or reimbursement differences between routes of delivery. Pay source stratified models explained 45-63% of the variation in the hospital-specific cesarean rates. Sensitivity analysis revealed that even a 50% change in the incidence of any independent variable would change the cesarean delivery rate by less than 2%.

Birth Rate↗

PubMed1989

[Effects of air pollutants on the respiratory system in young children].

A one year study on a random sample of 1225 Swiss children aged 0-5 years was conducted in four different areas (two urban, one suburban and one rural) of Switzerland to investigate the relationship between air pollution and respiratory symptoms. For each child daily symptoms over a six week period were recorded by their parents in the form of a standard diary and air pollution was assessed by personal NO2-samplers. 20% of the diaries were validated by comparison with the attending pediatrician's case-notes and showed good agreement (87%). The frequency of respiratory symptoms per child per day was found to increase with increasing levels of NO2 measured outdoors, but not with NO2 concentration indoors (when other indoor sources for NO2 where present). Possible other factors were accounted for by multiple regression analysis and the variables "season" and "child's susceptibility to colds" also showed a significant association with respiratory symptoms. But the relationship between NO2 outdoors and respiratory symptoms per child per day remained statistically significant. The multiple regression model explains 7% of the total variability. The result indicates that air pollution is a contributory factor in the development of respiratory symptoms in children.

Air Pollutants↗