The relationship between job strain and coronary heart disease: evidence from an english sample of the working male population.

BACKGROUND: Many, but not all, studies have reported that job strain is related to cardiovascular morbidity and mortality. To date, this relationship has not been tested on an English full population sample. This study examines whether the demand-control model of job strain contributes to our understanding of the determinants of coronary heart disease. METHODS: The analysis uses data from 4350 working men aged 20-64 in the 1993 Health Survey for England. Job demand and control characteristics were determined by questionnaire. Several health outcomes were examined: self-rated health; psychiatric health; angina and possible myocardial infarction, measured by the Rose questionnaire; doctor-diagnosed heart disease; any heart disease. The relationship between job strain and the health outcomes was determined by logistic regression analyses after controlling for known confounders. RESULTS: Those in high strain jobs consistently reported poorer health on all measures than men with lower strain. Similarly, men reporting low job strain were least likely to report poor health in 5/6 health outcomes. Those with intermediate levels of strain tended to have intermediate prevalence rates for poor health. The pattern of association between job strain and the CHD was independent of coronary risk factors. CONCLUSIONS: The analyses broadly support Karasek's demand-control model of job strain. Health selection into low strain jobs may account for the lack of an association between job strain and doctor diagnosed heart disease while independent associations between job strain and all CHD measures considered together indicate that job strain may have aetiological significance for heart disease.

Formation of infectious pancreatic necrosis virus-like particles following expression of segment A by recombinant semliki forest virus.

Segment A of the Sp strain (a Norwegian field isolate) of infectious pancreatic necrosis virus (IPNV) was amplified by reverse transcriptase polymerase chain reaction in two stages from RNA isolated from infected cells, and cloned into the Semliki Forest virus (SFV) expression vector pSFV1. Expression and correct processing of IPNV proteins was confirmed by transfection of RNA transcribed from this plasmid into BHK cells. This clone was then used to produce recombinant replication-defective SFV particles (rSFV) expressing the IPNV segment A. Immunofluorescence studies with conformation-dependent monoclonal antibodies to IPNV confirmed that the recombinant proteins produced after infection of the salmonid cell line CHSE-214 with such rSFV retain their antigenicity. Infection of the CHSE cells with the rSFV resulted in the formation of IPNV-like particles, which were similar in size and morphology to IPNV.

Potency testing of a live, genetically attenuated vaccine for salmonids.

Studies have been performed on the use of a live vaccine for immunization of salmonids against the bacterial disease furunculosis. The protection elicited by a kanamycin-resistant aroA mutant of A. salmonicida (Brivax I) and an unmarked aroA deletion mutant (Brivax II) has been examined, and data compared with protection seen using a freeze-dried Brivax II preparation and a commercial, oil-adjuvanted killed vaccine for furunculosis. Whilst high relative percent survival (RPS) values were seen in fish vaccinated with broth-grown Brivax I after a natural exposure to furunculosis (70-100%), much lower RPS values (30-40%) were seen with Brivax II vaccinated fish after an experimental challenge. Nevertheless, the freeze-dried Brivax II formulation performed as well as the broth-grown Brivax II formulation and a commercial vaccine in these studies. In addition, the environmental impact in terms of bacterial shedding into the tank water has been estimated, and shown to approximately 0.03% of the total inoculum used. Lastly, the freeze-dried formulation has been tested for its ability to infect fish and prime for lymphocyte proliferation and antibody production, relative to broth-grown preparations. In all three experiments no significant differences were seen between fish given the broth-grown and freeze-dried formulations. Such data, together with observations that the freeze-dried live preparation had an extended shelf life with the same potency as freshly grown bacteria, show that the potential exists for a commercially viable live vaccine to be produced for use in aquaculture.

Awareness of sexual partners' HIV status as an influence upon high-risk sexual behaviour among gay men.

OBJECTIVE: To evaluate the extent to which 'high-risk' sexual behaviour is influenced by awareness of partners' HIV status among gay men. DESIGN: Structured interviews and collection of saliva samples for anonymous linked testing for HIV-1 antibodies. SETTING: Genitourinary medicine clinics and the gay community. SUBJECTS: Men (n = 677) who reported sexual contact with another man in the last 5 years. RESULTS: The majority of respondents (63%) had had an HIV-antibody test. Analysis of data showed that in 15% of the respondents' 1380 partnerships, HIV status was known by both parties. However, the majority of partnerships involved only safe sex. Only 26% of the partnerships in which unprotected penetrative anal sex had occurred involved mutual knowledge of HIV status and was most likely to occur with regular rather than non-regular/causal partners. Logistic regression revealed that this latter association could not be explained in terms of mutual HIV status knowledge. CONCLUSIONS: Despite widespread HIV testing, the majority of gay men engaging in high-risk sex are unaware of their partner's HIV status.

PIP: The authors interviewed and collected saliva samples from 677 men who reported having sexual contact with other men in the preceding five years to assess the extent to which high-risk sexual behavior is influenced by awareness of partners' HIV status among gay men. Participants of mean age 32.6 years of a range of 16-71 years were recruited from genitourinary medicine clinics and the gay community over the period March 1991-April 1992. 52% were from London, 21% from Manchester, 18% from central England, 6% from Bristol, and 3% from elsewhere. 63% had previously had an HIV-antibody test. 94 (16%) of the 580 satisfactory saliva samples tested for HIV-1 antibodies were seropositive; 17 men were previously unaware of their HIV-positive serostatus. The 577 men who reported having a sex partner within the previous month provided information on 1380 partners during the period. 45% of the sexually active men reported engaging in some kind of penetrative anal sex in the previous month, while 23% reported having unprotected anal sex in the previous month. HIV status was known by both parties, however, in only 15% of the 1380 partnerships. 891 partnerships involved no penetrative anal sex and 1107 involved only nonpenetrative or penetrative sex always with a condom. Further, 26% of the partnerships in which unprotected penetrative anal sex took place involved mutual knowledge of HIV status and was most likely to occur with regular instead of nonregular/casual partners. It is of interest that 114 partners were known to be married and 311 were of unknown marital status. Higher social class was associated with a reduced likelihood of having risky sex and high-risk sex was more common in partnerships in which there was an age gap in excess of two years between partners.

Risk behaviour, anti-HIV and anti-hepatitis B core prevalence in clinic and non-clinic samples of gay men in England, 1991-1992.

OBJECTIVE: To describe the sexual risk behaviour of and HIV and hepatitis B antibody prevalence in gay men in England. DESIGN: Cross-sectional. RESPONDENTS: Gay men recruited from community settings (bars, clubs, gay organizations) and genito-urinary clinics in London, Manchester, the Midlands and Bristol; men who participated in an earlier study. METHODS: Interview including demographic information, sexual behaviour, partner type and health service use. Subjects donated saliva, which was screened for antibodies to HIV-1 by immunoglobulin G (IgG) antibody capture enzyme-linked immunosorbent assay (GACELISA) and to hepatitis B core (HBc) antigen by IgG antibody capture radioimmunoassay (GACRIA). RESULTS: Ninety-four out of 580 (16.2%) men were HIV-antibody-positive; 6.2% of men aged < or = 25 years were positive versus 19.5% of men aged > or = 26 years. HIV-antibody prevalence was highest in London (21.1%), and twice that previously reported outside London (10.5%). Ninety-four out of 568 (16.5%) men were HBc-antibody-positive; 6.9% of men aged < or = 25 years were positive versus 19.7% of men aged > or = 26 years. Anti-HBc prevalence was highest in London (19.8 versus 12.7% outside London). Manual workers were more likely to be anti-HBc-positive, as were men who reported recent high-risk intercourse. Sexually transmitted diseases associated with frequent partner change (gonorrhoea, non-specific urethritis) were reported. CONCLUSION: The HIV epidemic in gay men in England continues, particularly outside London, where prevalence was double that of previous studies. We found relatively high rates of infection in young men whose main sexual experience has been in a time of unprecedented awareness of AIDS. Our data on hepatitis B suggests that further pro-active immunization programmes are urgently required. These findings add to concerns about provision of interventions targeting gay men.

Problems in the assessment of outcome in a back pain clinic.

A sample of 72 patients attending the rheumatological back pain clinic of a district general hospital were interviewed at home, before their visit, about their expectations of the clinic. They also completed a Back Pain Disability Questionnaire. Fifty of the patients were recontacted by mail 3 months after their first clinic attendance and asked to complete the Back Pain Disability Questionnaire together with satisfaction questionnaires. Patients' reports, both with regard to expectations and satisfaction, particularly emphasized the importance of communication. One-third of the follow-up sample rated their clinic attendance as unhelpful, and although such views correlated with lack of improvement in pain and disability, other factors are involved in patients' evaluations. Significant correlations were obtained between subjective outcomes and health locus of control, social class and previous hospital treatment. Patient satisfaction may be a valuable measure of outcome in assessing the efficacy of back pain treatment.

Effects of referral to a specialist for headache.

Patients consulting neurological outpatient clinics for headaches that were found not to be due to a serious structural lesion were followed up one year afterwards. Considerable improvement in symptoms was found in the sample. This was only partly attributable to any medical treatment received at the clinics or subsequently from a general practitioner. Improvement was associated with previously expressed satisfaction with the clinic consultation, and a nonspecific `placebo' response is postulated.

Social dimensions of healing: a longitudinal study of outcomes of medical management of headaches.

The social sciences have made few direct empirical contributions to the understanding of 'non-specific' benefits of treatment and generally the symbolic healing of indigenous non-Western medicine has received most attention in this field. This paper reports some results of a wider study of neurological clinics in England in which it is shown that a sample attending for headaches experienced considerable improvement in symptoms when followed up 1 year after attendance. Most of this improvement appeared not to be due to any intended treatments received at the clinics but could be attributed to the quality of patients' immediate responses to clinic attendance as assessed from reach interviews conducted after their consultations. This relationship between immediate 'satisfied' response and subsequent symptomatic improvement is interpreted in terms of the general levels of expectancy and sense of potential control achieved by obtaining referral to a specialist which directly enhanced recovery in those patients who felt the doctor's actions to be directly relevant to their personal concerns. Disappointment with the doctor reduced the 'non-specific' therapeutic benefits of the hospital referral. The intimate connections of patient satisfaction, treatment received and subsequent outcomes need more careful consideration in social studies of Western medicine.