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PubMed2001

Unsafe injection practices in a cohort of injection drug users in Vancouver: could safer injecting rooms help?

BACKGROUND: In several European countries safer injecting rooms have reduced the public disorder and health-related problems of injection drug use. We explored factors associated with needle-sharing practices that could potentially be alleviated by the availability of safer injecting rooms in Canada. METHODS: The Vancouver Injection Drug User Study is a prospective cohort study of injection drug users (IDUs) that began in 1996. The analyses reported here were restricted to the 776 participants who reported actively injecting drugs in the 6 months before the most recent follow-up visit, during the period January 1999 to October 2000. Needle sharing was defined as either borrowing or lending a used needle in the 6-month period before the interview. RESULTS: Overall, 214 (27.6%) of the participants reported sharing needles during the 6 months before follow-up; 106 (13.7%) injected drugs in public, and 581 (74.9%) reported injecting alone at least once. Variables independently associated with needle sharing in a multivariate analysis included difficulty getting sterile needles (adjusted odds ratio [OR] 2.7, 95% confidence interval [CI] 1.8-4.1), requiring help to inject drugs (adjusted OR 2.0, 95% CI 1.4-2.8), needle reuse (adjusted OR 1.8, 95% CI 1.3-2.6), frequent cocaine injection (adjusted OR 1.6, 95% CI 1.1-2.3) and frequent heroin injection (adjusted OR 1.5, 95% CI 1.04-2.1). Conversely, HIV-positive participants were less likely to share needles (adjusted OR 0.5, 95% CI 0.4-0.8), although 20.2% of the HIV-positive IDUs still reported sharing needles. INTERPRETATION: Despite the availability of a large needle-exchange program and targeted law enforcement efforts in Vancouver, needle sharing remains an alarmingly common practice in our cohort. We identified a number of risk behaviours--difficulty getting sterile needles, needle sharing and reuse, injection of drugs in public and injecting alone (one of the main contributing causes of overdose)--that may be alleviated by the establishment of supervised safer injecting rooms.

British Columbia↗

PubMed1991

The effect of a cost sharing provision in Japan.

This study evaluated the effect of a 10% cost sharing provision, introduced in October 1984, on demand for medical services. We analysed the data of 1701 health insurance societies, all of which joined the National Federation of Health Insurance Societies between 1983 and 1985. The case rate (per 1000 persons) and the number of serviced days (per case) were analysed as indicators of demand for inpatient, outpatient and dental medical services. The case rate was considered to be an indicator of the patient's behaviour, while the number of serviced days was influenced by the doctor's behaviour. Multiple linear regression analysis was used with each indicator to isolate the effect of the cost sharing provision, adjusted for other variables which influenced demand for medical services. The case rate was reduced significantly in all medical services. This means that a patient was discouraged from using a medical facility by the cost sharing provision. There was little difference among medical services. The number of serviced days was also reduced significantly in all medical services. There was a large difference among medical services. The effect on outpatient service was much greater than that on any other service.

Cost Sharing↗

PubMedDate not supplied

Shared antigenic determinants of immunoglobulins in phylogeny and in comparison with T-cell receptors.

1. Immunoglobulins are a complex multigene family of proteins specified by genes encoding variable (V), sometimes diversity (D), joining (J), and constant (C) domains. 2. Cross-reactions involving conformational determinants related to the VHa system of rabbits occur on heavy chains of vertebrate species ranging from elasmobranchs to man. 3. Serological markers characteristic of mu chains, the heavy chain of the IgM macroglobulins, occur on homologous heavy chains of species representing all vertebrate classes. 4. Serological markers characteristic of gamma type heavy chains, the major isotype in man, are restricted to the mammals, but are found on representatives of even the most primitive mammals, the egg-laying monotremes. 5. Variable region markers characteristic of lambda light chains are shared by light chains of shark and man. 6. Certain idiotypic markers defined by combining site V region sequences are broadly distributed in evolution. 7. Use of synthetic peptides as antigens and in epitope mapping show that amino acid sequences from the third framework region of the variable domain are broadly shared among light chain in phylogeny and between light chains and T-cell receptor beta chains. 8. The "switch peptides" linking the V and C domains of light chains and T-cell receptors, specified by the C-terminal portion of the J segment and the N-terminus of the constant region, are exposed in the three-dimensional structure of immunoglobulin or Tcrs, show striking homology, and form broadly shared antigenic determinants characteristic of immunoglobulins. 9. Although the multigene nature of the immunoglobulins and the complexity of antigenic determinants expressed by these large proteins renders comparison among molecules difficult, serum immunoglobulins and the closely related T-cell receptors express numerous shared determinants defined on the basis of amino acid sequence homology and three-dimensional conformations.

Amino Acid Sequence↗

PubMedDate not supplied

The role of negative interpretations of grief reactions in emotional problems after bereavement.

This study explored the role of negative interpretations of grief reactions in emotional problems after bereavement, with 234 individuals who had been confronted with the death of a close relative. It was found that negative interpretations of grief reactions were highly associated with the degree to which these reactions were experienced as distressing, the degree to which mourners engaged in avoidance behaviours and the severity of symptoms of traumatic grief and depression, even when controlling for the frequency of grief reactions and the influence of relevant background variables. Furthermore, behavioural and cognitive avoidance strategies were significantly related to the severity of traumatic grief and depression. Negative interpretations of grief reactions and rumination explained most variance in symptom severity, when controlling for the shared variance between the predictor variables. The results have implications for the treatment of emotional problems after bereavement.

Adaptation, Psychological↗

PubMed1989

Staff perceptions of shared governance.

Future research must consider a number of potential influencing variables, focus on before and after comparisons and comparisons among types of shared governance models, and include replications and longitudinal studies. In addition, qualitative, descriptive data regarding the life of the organization will be beneficial in interpreting the more quantitative findings. The ideal of controlling all variables is simply not possible when one is studying a complex organization. With ingenuity, creativity, and a blend of methodologies, however, researchers may come considerably closer to understanding more about how and why shared governance can work effectively.

Adult↗

PubMed1999

Shared antigenic epitopes and pathobiological functions of anti-p185(her2/neu) monoclonal antibodies.

We have studied two anti-p185 antibodies: the monoclonal antibody 7. 16.4 and rhuMAb 4D5, which were raised against the the ectodomain of rat (p185(neu)), and the human (p185(her2/neu)) homolog, respectively. Studies on the structure of these two antibodies indicate that they share structural similarity in the variable region, especially the CDR3 region, which determines the antibody-antigen interaction. Further studies by flow cytometry revealed that 7.16.4 can compete with rhuMAb4D5 for binding to the cell surface p185(her2/neu), suggesting that these two antibodies share an epitope on the p185 receptor. Furthermore, 7.16.4 can also inhibit proliferation and transformation caused by p185(her2/neu). Moreover the rhuMAb 4D5 binds to the rat p185(neu). With the observation that 7.16.4 positively stains human breast cancer tissues that overexpress p185(her2/neu), 7.16.4 may be useful for the pathological diagnosis and therapy of human tumors.

3T3 Cells↗

PubMed2002

Employer-sponsored insurance: how much financial protection does it provide?

The authors examine the generosity of private employer health insurance coverage using data from two large national surveys of employers. Generosity is measured as the expected out-of-pocket share of medical expenditures for a standard population, given the provisions of the coverage. On average, those covered by employer-sponsored insurance can expect to pay 25 percent of expenditures out of pocket. There is little variability across plans in this share, though plans offered by smaller employers are somewhat less generous than those offered by larger employers. Individuals who incur high costs pay a smaller share of the bill than do those with lower levels of spending. The generosity of employer-sponsored plans increased slightly in the 1990s.

Adult↗

PubMed2000

Needle sharing: a longitudinal study of female injection drug users.

The objective of this study was to examine the psychosocial risk and protective factors related to needle-sharing behavior among female intravenous drug users (IDUs) positive (N = 96) and negative (N = 128) for human immunodeficiency virus (HIV). Participants in this longitudinal study were interviewed individually at two points in time, with a 6-month interval between interviews. The interviewers used a structured questionnaire, which included psychosocial measures and questions about drug and sexual risk behaviors. Data were analyzed using Pearson correlations and hierarchical regression analyses. The findings supported a developmental model in which the psychosocial domains and HIV status predicted T1 (initial) needle-sharing behavior, which in turn was related to T2 (follow-up) needle-sharing behavior. In addition, the relationship between personality and peer risk factors and T2 needle sharing was buffered by family-related protective factors. While HIV-positive status had a direct effect on T1 needle sharing with strangers, its effect was mediated by all of the psychosocial variables in its relation to T1 needle sharing with familiar people. Comparisons of these results were made with a companion study of male IDUs. The results suggest several intervention and treatment approaches that can be implemented at different points in the developmental pathways leading to risky needle-sharing practices among female IDUs.

Adult↗

PubMed2004

Work flow policy and within-worker and between-workers variability in performance.

Work flow policies are shown to induce a change in average between-workers variability (worker heterogeneity) and within-worker variability in performance times. In a laboratory experiment, the authors measured the levels of worker heterogeneity and within-worker variability under an individual performance condition, a work sharing condition, and a fixed assignment condition. The work sharing policy increased the levels of worker heterogeneity and worker variability, whereas the fixed assignment policy decreased them. These effects, along with work flow policy main effects on mean performance times and variability are examined. This article represents an initial step in understanding effects that may be important in the selection of an operating policy, the ignorance of which may lead to costly misestimates of performance.

Analysis of Variance↗

PubMed2006

Comparative postnatal ontogeny of the skull in the australidelphian metatherian Dasyurus albopunctatus (Marsupialia: Dasyuromorpha: Dasyuridae).

We describe the cranial ontogeny of an australidelphian marsupial, Dasyurus albopunctatus, using a combination of qualitative and quantitative approaches. We examined in detail qualitative morphological changes of just-weaned individuals as compared to old adults; specifically, changes in 31 morphological structures (e.g., processes, foramina) and 38 changes in cranial joints. We also interpreted growth-invariant structures in terms of their functional relevance. We performed a multivariate allometry analysis based on 14 cranial measurements taken from 31 specimens encompassing the entire postweaning period. Three variables (height of occipital plate, breadth of braincase, and height of mandible) showed the same allometric trends in D. albopunctatus and the three marsupial species studied previously in the same framework (Didelphis albiventris, Lutreolina crassicaudata, and Dromiciops gliroides). In addition, D. albopunctatus shared allometric trends in two variables (length of the upper postcanine row and length of the orbit) with the microbiotheriid D. gliroides. Most of the growth trends observed are interpreted as linked to the predominantly carnivorous dietary habit of adult D. albopunctatus. Because dasyuromorphians are most likely basal to the major Australasian radiation of marsupials, knowledge of ontogenetic changes in D. albopunctatus may shed light on the evolution of ontogeny in the highly diverse Australasian marsupial fauna.

Animals↗

PubMed2005

Dispositional optimism, trait anxiety, and coping: unique or shared effects on biological response to fertility treatment?

The aim of this study was to examine the unique and shared predictive power of psychological variables on reproductive physical health. Three months before fertility treatment, 97 women completed measures of dispositional optimism, trait anxiety, and coping. Information about biological response to treatment (e.g., estradiol level) was collected from medical charts after treatment. Structural equation modeling showed that measured psychological variables were all significant indicators of a single latent construct and that this construct was a better predictor of biological response to treatment than was any individual predictor. This research contributes to evidence suggesting that the health benefits of dispositional optimism are due to its shared variance with neuroticism.

Adaptation, Psychological↗

PubMed1988

Prognostic variability among chronic pain patients: implications for study design, interpretation, and reporting.

Chronic pain patients share many characteristics, but there is important prognostic variability among them. By selecting for certain characteristics, different recruitment methods and entry criteria for clinical or research programs may influence the likelihood of success regardless of treatment efficacy. This was demonstrated when subjects (n = 55) were recruited through lay publicity for a clinical trial of therapy for chronic back pain. In comparison to routine pain clinic patients (n=61), subjects in the clinical trial were better educated, were more often employed, had more favorable personality profiles, and were less likely to have had surgery or narcotic use (all p less than 0.004). Pain relief was significantly better for clinical trial subjects, apparently due to baseline prognostic differences rather than uniquely efficacious therapy. We conclude that chronic pain patients vary in prognostically important ways; that recruitment methods and criteria strongly influence these characteristics; and that greater attention to these details is needed when interpreting and reporting clinical research.

Adult↗

PubMed2004

Posttraumatic stress disorder and depression following trauma: understanding comorbidity.

OBJECTIVE: Posttraumatic stress disorder (PTSD) and major depression occur frequently following traumatic exposure, both as separate disorders and concurrently. This raises the question of whether PTSD and depression are separate disorders in the aftermath of trauma or part of a single general traumatic stress construct. This study aimed to explore the relationships among PTSD, depression, and comorbid PTSD/depression following traumatic injury. METHOD: A group of 363 injury survivors was assessed just prior to discharge from hospital and 3 and 12 months postinjury. Canonical correlations were used to examine the relationship between PTSD and depression symptom severity and a set of predictor variables. Multinomial logistic regression was used to identify whether the diagnostic categories of PTSD, depression, and comorbid PTSD/depression were associated with different groups of predictors. RESULTS: The majority of psychopathology in the aftermath of trauma was best conceptualized as a general traumatic stress factor, suggesting that when PTSD and depression occur together, they reflect a shared vulnerability with similar predictive variables. However, there was also evidence that in a minority of cases at 3 months, depression occurs independently from PTSD and was predicted by a different combination of variables. CONCLUSIONS: While PTSD and comorbid PTSD/depression are indistinguishable, the findings support the existence of depression as a separate construct in the acute, but not the chronic, aftermath of trauma.

Adult↗

PubMed1997

Withholding research results in academic life science. Evidence from a national survey of faculty.

OBJECTIVES: To identify the prevalence and determinants of data-withholding behaviors among academic life scientists. DESIGN: Mailed survey of 3394 life science faculty in the 50 universities that received the most funding from the National Institutes of Health in 1993. PARTICIPANTS: A total of 2167 faculty responded to the survey, a 64% response rate. OUTCOME MEASURES: Whether respondents delayed publication of their research results for more than 6 months and whether respondents refused to share research results with other university scientists in the last 3 years. RESULTS: A total of 410 respondents (19.8%) reported that publication of their research results had been delayed by more than 6 months at least once in the last 3 years to allow for patent application, to protect their scientific lead, to slow the dissemination of undesired results, to allow time to negotiate a patent, or to resolve disputes over the ownership of intellectual property. Also, 181 respondents (8.9%) reported refusing to share research results with other university scientists in the last 3 years. In multivariate analysis, participation in an academic-industry research relationship and engagement in the commercialization of university research were significantly associated with delays in publication. Odds ratios (ORs) and 95% confidence intervals (CIs) were 1.34 (1.07-1.59) and 3.15 (2.88-3.41), respectively. Variables associated with refusing to share results were conducting research similar to the Human Genome Project (OR, 2.09; 95% CI, 1.75-2.42), publication rate (OR, 1.02; 95% CI, 1.01-1.03), and engagement in commercialization of research (OR, 2.45; 95% CI, 2.08-2.82). CONCLUSIONS: Withholding of research results is not a widespread phenomenon among life-science researchers. However, withholding is more common among the most productive and entrepreneurial faculty. These results also suggest that data withholding has affected a significant number of life-science faculty and further study on data-withholding practices is suggested.

Biological Science Disciplines↗

PubMed2003

Genetic and environmental influences on substance initiation, use, and problem use in adolescents.

BACKGROUND: We conducted a sibling/twin/adoption study of substance initiation, use, and problem use, estimating the relative contribution of genetic and environmental influences on these phenotypes in adolescents. METHODS: The participants were 345 monozygotic twin pairs, 337 dizygotic twin pairs, 306 biological sibling pairs, and 74 adoptive sibling pairs assessed by the Colorado Center for the Genetics and Treatment of Antisocial Drug Dependence, Denver and Boulder. The initiation, use, and problem use of tobacco, alcohol, marijuana, and other illicit drugs were assessed. Tetrachoric correlations were computed for each group, and univariate model-fitting analyses were conducted. RESULTS: There were moderate to substantial genetic influences, with the exception of alcohol use and any drug use, and modest to moderate shared environmental influences on substance initiation, use, and problem use. For alcohol and any drug, heritability was higher and the magnitude of shared environmental influences was lower for problem use than for initiation or use. Environmental influences shared only by twin pairs had a significant effect on tobacco initiation, alcohol use, and any drug use. For tobacco use, tobacco problem use, and marijuana initiation, heritability was higher and the magnitude of shared environmental influences was lower in female than in male adolescents. There was no evidence for sex-specific genetic or shared environmental influences on any variable. CONCLUSIONS: The moderate to substantial heritabilities found for adolescents in the present study are comparable to those found in twin studies of adult substance use and substance use disorders. The finding that problem use is more heritable than initiation and use is also consistent with the results of adult twin studies. The significance of environmental influences shared only by twin pairs on tobacco initiation, alcohol use, and any drug use suggests the influences of peers, accessibility of substances, and sibling interaction.

Adolescent↗

PubMed1992

Methods for inference on transmission in seroprevalence data for multiple infections.

When risk factors for an infectious disease are unknown, a method commonly employed is to investigate parallels with known infections (covariate infections). Data sets of value here are those for specified populations in which the seroprevalence of antibodies for multiple infections has been ascertained. The use of markers of covariate infections in multivariable analyses is problematic when the covariate infection is not itself an independent risk factor for the outcome of interest. In the performance of these analyses, the authors recommend the following strategy: 1) For estimates of the effects of measured risk factors on the outcome, adjustment for the covariate infection should not be done; this will avoid problems of overadjustment. 2) After control for the measured risk factors, an estimate of the "effect" of the covariate infection may be used as an indicator of the presence of unmeasured shared risk factors. 3) When shared, measured risk factors exist, the authors propose the use of methods developed for analysis of repeated measures of categorical variables to assist in inference about shared mechanisms of action of these risk factors. This analytic strategy takes advantage of the method of analogy for building understanding of transmission of new agents through their parallels with better known ones and is useful in the development of hypotheses.

Communicable Diseases↗

PubMed1982

Serology of Neisseria gonorrhoeae: W-antigen serogrouping by coagglutination and protein I serotyping by enzyme-linked immunosorbent assay both detect protein I antigens.

A total of 224 strains were serogrouped by coagglutination (COA) and serotyped by protein I enzyme-linked immunosorbent assay (ELISA). Of these strains, 61 were from patients with disseminated gonococcal infection, 21 were from patients with pelvic inflammatory disease, and 115 were from patients with uncomplicated gonococcal infection in Singapore, the Philippines, and Denmark. Twenty-seven were laboratory reference strains. Of the patient strains, 102 belonged to COA serogroup WI, and all of the 100 strains that typed with protein I serotypes 1, 2, or 3 were in this group. Most of the strains of gonococci from the 61 patients with disseminated gonococcal infection were within this group (COA WI, 53 or 87%; protein I serotypes 1, 2, or 3, 51 or 84%). All 46 strains that were protein I serotypes 4 through 7 were also COA serogroup WII. Protein I serotypes 8 and 9 accounted for 49 (25%) of the 197 patient strains. Twenty-eight of these strains typed as COA serogroup WII, 20 typed as serogroup WIII, and 1 typed as serogroups WII and WIII. COA W serogrouping and protein I ELISA both appeared to detect antigens on the protein I molecule of the outer membrane of Neisseria gonorrhoeae. Protein I serotyping, which uses unboiled organisms, may generally recognize more variable and surface-exposed antigenic determinants. In contrast, COA W serogrouping, which uses boiled organisms, may recognize less exposed shared antigenic determinants in addition to variable protein I antigenic determinants. Both methods may prove useful for further studies of the epidemiology and pathogenesis of gonorrhea.

Agglutination Tests↗

PubMed2006

Semi-supervised discovery of differential genes.

BACKGROUND: Various statistical scores have been proposed for evaluating the significance of genes that may exhibit differential expression between two or more controlled conditions. However, in many clinical studies to detect clinical marker genes for example, the conditions have not necessarily been controlled well, thus condition labels are sometimes hard to obtain due to physical, financial, and time costs. In such a situation, we can consider an unsupervised case where labels are not available or a semi-supervised case where labels are available for a part of the whole sample set, rather than a well-studied supervised case where all samples have their labels. RESULTS: We assume a latent variable model for the expression of active genes and apply the optimal discovery procedure (ODP) proposed by Storey (2005) to the model. Our latent variable model allows gene significance scores to be applied to unsupervised and semi-supervised cases. The ODP framework improves detectability by sharing the estimated parameters of null and alternative models of multiple tests over multiple genes. A theoretical consideration leads to two different interpretations of the latent variable, i.e., it only implicitly affects the alternative model through the model parameters, or it is explicitly included in the alternative model, so that the interpretations correspond to two different implementations of ODP. By comparing the two implementations through experiments with simulation data, we have found that sharing the latent variable estimation is effective for increasing the detectability of truly active genes. We also show that the unsupervised and semi-supervised rating of genes, which takes into account the samples without condition labels, can improve detection of active genes in real gene discovery problems. CONCLUSION: The experimental results indicate that the ODP framework is effective for hypotheses including latent variables and is further improved by sharing the estimations of hidden variables over multiple tests.

Algorithms↗