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Biomedical subjects

L Whitaker

Publications and source records attributed to L Whitaker.

At least 19 recordsLinked to original sources
PubMed1996

Community service needs of people with HIV infection in London.

The objectives of this study were to describe the expressed needs for community services of HIV-infected individuals by disease stage, gender and transmission category and the barriers which prevent the receipt of such services. Structured interviewer-administered questionnaires concerning a 6-month retrospective period were used to obtain information on need for community services and problems which prevented the receipt of services. The study sample included 70 homosexual men with asymptomatic HIV disease, 42 homosexual men with symptomatic non-AIDS, 53 homosexual men with AIDS, 23 heterosexual men, 29 heterosexual women, 9 male and 9 female injecting drug users. The main outcome measures were the extent to which needs for community services were met and person/service combinations for which problems or barriers prevented the receipt of community services. On average, subjects expressed a need for 10 categories of community services over the 6-month period: homosexuals expressed a mean of 10, heterosexuals 10, injecting drug users 11, subjects with asymptomatic HIV infection 9, subjects with symptomatic non-AIDS 11, subjects with AIDS 13, men 9 and women 14. A total of 58% of community service needs were always met, 6% were rarely not met, 16% were sometimes not met, 6% were often not met and 14% were not met at all. The extent to which subjects felt that their needs were met was similar for the different study groups, but the needs of women were met somewhat less frequently than those of men. Similarly, people with AIDS felt that their needs were met slightly less often. Reported levels of unmet need were high for a wide range of services. The most common reason subjects gave for not having received a community service for which they expressed a need was ignorance of where or how to obtain the service. This was mentioned in one-third of all such cases. Anxieties over the competence with which a service would be rendered was mentioned in 13% of cases and long waiting times in 11%. The frequencies of unmet need for many community services were high and often seemed to arise either from a lack of awareness on the part of subjects on how and where services could be obtained or from doubts about the relevance of services offered. Both of these barriers should be surmountable through the provision of better information to patients, extending user involvement in service development and the better co-ordination of service delivery through care management approaches.

Adult↗
PubMed1995

Provision of sex education and early sexual experience: the relation examined.

OBJECTIVES: To explore the relation between receipt of sex education and experience of first intercourse. SUBJECTS AND DESIGN: The national survey of sexual attitudes and lifestyles is based on a sample of 18,876 respondents aged 16-59, randomly selected from the Post Office's small-user postcode address file. Data were collected between May 1990 and November 1991 by personal interviews combining a self administered questionnaire with a face to face interview. MAIN OUTCOME MEASURES: Age at first intercourse, use of contraception at first intercourse, actual and preferred source of sex education (including school based lessons). RESULTS: Median age at first intercourse fell by four years for women and three years for men over the past four decades, to 17 for both men and women aged 16-19 at the time of interview. Of those respondents for whom school was the main source of information about sexual matters, men were less likely, and women no more likely, to have had intercourse before the age of 16 than were those citing other main sources, such as friends and the media. Both men and women were more likely to have used some method of contraception. In multivariate analysis, these effects remained after controlling for the effect of current age, educational attainment, and religious affiliation. CONCLUSIONS: These data provide no evidence to support the concern that provision of school sex education might hasten the onset of sexual experience. These findings have important implications for the provision of sexual health education and highlight the need to carry out prospective and randomised studies of the impact of sex education.

Adolescent↗
PubMed1995

HIV positive patients first presenting with an AIDS defining illness: characteristics and survival.

OBJECTIVES: To study the presentation and survival of patients who present with their first diagnosis of being HIV positive at the same time as their AIDS defining illness. DESIGN: Retrospective study of patients presenting with AIDS between 1991 and 1993. SETTING: Department of genitourinary medicine, St Mary's Hospital, London. MAIN OUTCOME MEASURES: AIDS defining illness at presentation and survival after diagnosis of AIDS. RESULTS: Between January 1991 and December 1993, 97 out of 436 patients (22%) presented with their first AIDS defining illness coincident with their first positive result of an HIV test (group B). The remaining 339 patients (78%) had tested positive for HIV-1 infection within the previous eight years and had consequently been followed up in clinics before developing their first AIDS defining illness (group A). The two groups of patients did not differ in age and sex distribution, risk factors for HIV-1 infection, nationality, country of origin, or haematological variables determined at the time of the AIDS defining illness. However, the defining illnesses differed between the two groups. Illnesses associated with severe immunodeficiency (the wasting syndrome, cryptosporidiosis, and cytomegalovirus infection) were seen almost exclusively in group A whereas extrapulmonary tuberculosis and Pneumocystis carinii pneumonia were more common in group B. The survival of patients in group B after the onset of AIDS was significantly longer than that of patients in group A as determined by Kaplan-Meier log rank analysis (P = 0.0026). CONCLUSIONS: Subjects who are HIV positive and present late are a challenge to the control of the spread of HIV infection because they progress from asymptomatic HIV infection to AIDS without receiving health care. The finding that presentation with an AIDS defining illness coincident with a positive result in an HIV test did not have a detrimental effect on survival gives insights into the effects of medical intervention on disease progression after a diagnosis of AIDS.

AIDS Serodiagnosis↗
PubMed1995

The use of air or CO2 as insufflation agents for double contrast barium enema (DCBE): is there a qualitative difference?

One hundred consecutive out-patients referred for double contrast barium enema (DCBE) were randomized in a double-blind prospective study to receive either air or CO2 as an insufflation agent. Each examination was performed by the same radiologist and radiographer. The two groups were equally matched for age and sex. Each completed examination was independently assessed by three radiologists for a variety of parameters. The results show that the patients receiving air as an insufflation agent had better overall colonic distension than the group receiving CO2 and that this was statistically significant (P = 0.0004). There was no significant difference in the mean time taken to perform the examination in the two groups nor was there any significant difference in mucosal coating or preparation. In conclusion, our results suggest that poor colonic distension is a potential problem when CO2 is used for DCBE and that this cannot be solely attributed to the time taken to perform the examination. Poor distension could lead to diagnostic errors and this may outweigh the advantages in patient acceptability when using CO2 as an insufflation agent.

Adult↗
PubMed1995

Estimating the sexual mixing patterns in the general population from those in people acquiring gonorrhoea infection: theoretical foundation and empirical findings.

STUDY OBJECTIVES: To describe mathematically the relationship between patterns of sexual mixing in the general population and those of people with gonorrhoea infection, and hence to estimate the sexual mixing matrix for the general population. DESIGN: Integration of data describing sexual behaviour in the general population, with data describing sexual behaviour and mixing among individuals infected with gonorrhoea. Use of these data in a simple mathematical model of the transmission dynamics of gonorrhoea infection. SETTING: The general population of London and a genitourinary medicine (GUM) clinic in west London. PARTICIPANT: These comprised 1520 men and women living in London who were randomly selected for the national survey of sexual attitudes and lifestyles and 2414 heterosexual men and women who presented to the GUM clinic with gonorrhoea. MAIN RESULTS: The relationship between sexual mixing among people with gonorrhoea and sexual mixing in the general population is derived mathematically. An empirical estimate of the sexual mixing matrix for the general population is presented. The results provide tentative evidence that individuals with high rates of acquisition of sexual partners preferentially select other individuals with high rates as partners (assortative mixing). CONCLUSIONS: Reliable estimates of sexual mixing have been shown to be important for understanding the evolution of the epidemics of HIV infection and other sexually transmitted diseases. The possibility of estimating patterns of sexual mixing in the general population from information routinely collected in gonorrhoea contact tracing programmes is demonstrated. Furthermore, the approach we describe could, in principle, be used to estimate the same patterns of mixing, using contact tracing data for other sexually transmitted diseases, thus providing a way of validating our results.

Adolescent↗
PubMed1994

Using STD occurrence to monitor AIDS prevention.

Monitoring the effects of AIDS prevention programmes is increasingly important but methodologically difficult. The use of surveillance derived measures of the occurrence of sexually transmitted diseases as indicators of high risk sexual behaviour, or of HIV incidence, has been widely recognized as a possible approach. This paper first examines the theoretical and empirical basis for this strategy, and highlights, using examples, some of the pitfalls in the interpretation of trends in sexually transmitted disease occurrence. Problems arising in the interpretation of the types of STD surveillance data currently available in countries in Western Europe are discussed. Ways in which STD surveillance systems might be developed so as to enhance their value in monitoring AIDS prevention are proposed. The paper goes on to identify areas of clinical and epidemiological research which might improve our ability to interpret such enhanced STD surveillance data.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Changing use of hospital services and costs at a London AIDS referral centre, 1983-1989.

OBJECTIVE: To describe the use of hospital-based services and associated costs over time for HIV-infected individuals by disease stage and year of treatment. METHODS: Data on service use were abstracted from inpatient and outpatient case-notes of 459 HIV-infected patients (121 asymptomatic and 338 AIDS patients) treated at St Mary's Hospital, London between 1983 and 1989. Cost estimates were derived from a survey of the 37 departments involved with HIV-related care. The number and type of admissions and outpatient visits, referral and discharge venues, number and type of tests and procedures performed, drugs prescribed and associated costs for the study period were the outcome measures used. RESULTS: Most patients were homosexual men. At the time of first HIV-related visit, 80.7% lived in London. Most day cases and planned admissions were organized through the outpatient clinic; 31% of emergency admissions were initiated by patients themselves. For people with AIDS the number of day case admissions increased while planned admissions decreased. There was a marked reduction in the duration of inpatient stays, especially for AIDS patients. Costs associated with inpatient care decreased concomitantly. The number of outpatient visits for patients with symptomatic disease increased, resulting in increased outpatient expenditure. Asymptomatic patients had fewer inpatient tests, while outpatient tests did not change over time; costs followed similar patterns. Mean inpatient and outpatient drug-days prescribed did not change nor did average inpatient drug-costs although outpatient drug-costs increased. Inpatient tests performed on symptomatic non-AIDS patients decreased, while mean outpatient tests increased; average costs followed similar patterns. Inpatient drug-days prescribed and costs remained the same, while outpatient drug-days and average drug-costs increased during the study period. For AIDS patients, the number of inpatient tests performed and their average costs decreased but outpatient tests performed increased, though their average costs remained the same. Mean inpatient drug-days prescribed and average drug-costs decreased, while number of outpatient drug-days prescribed and average drug-costs increased markedly over time. For each disease category, expenditure on admissions and related tests decreased over time, while expenditure on outpatient visits and drug-costs increased. CONCLUSIONS: The shift from an inpatient- to an outpatient-based service has resulted in fewer patients being investigated and treated in hospital and more as outpatients. This has resulted in a reduction of inpatient-related costs, while outpatient-related costs have increased. The overall contribution of drug-costs to the total cost has increased greatly over time. With the anticipated advent of new antiviral compounds, the importance of ascertaining their effectiveness as well as their efficacy will become crucial.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Changing presentation and survival, service utilization and costs for AIDS patients: insights from a London referral centre.

OBJECTIVE: To describe the use of services and associated costs for HIV-infected patients by stage of infection in the context of changing patterns of presentation and survival. METHODS: A retrospective analysis of inpatient and outpatient case-notes of 335 AIDS patients and a survey of HIV-related care provided by 37 departments at St Mary's Hospital, London. Survival from time of diagnosis of AIDS, time from diagnosis of HIV infection to AIDS, and use and costs of services per patient-year were outcome measures. RESULTS: During the study period 1 January 1982 to 30 September 1989, 152 AIDS patients were diagnosed before 1987 (group 1) and 183 since 1987 (group 2), most of whom were homosexual men. The median interval of first HIV-related visit to diagnosis of AIDS increased from 0 (group 1) to 264 days (group 2; P < 0.0001). Median survival from AIDS diagnosis increased from 14.6 (group 1) to 21.0 months (group 2; P < 0.02). Group 2 patients used fewer inpatient services than group 1 patients irrespective of disease stage. Symptomatic patients in group 2 used more outpatient services than group 1 patients. Total HIV-related expenditure was lower for patients without AIDS in group 2 than in group 1, while expenditure for AIDS patients remained similar. CONCLUSION: Earlier patient presentation, a shift from inpatient- to outpatient-based clinical care and increased survival from time of AIDS diagnosis has occurred. Increased drug expenditure was offset by reduced inpatient expenditure. Total expenditure per patient-year was stable; increased survival and introduction of new drugs will increase future lifetime use of resources.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Raynaud's syndrome: diagnosis and treatment.

Patient care and research in clinical vascular surgery have traditionally and appropriately focused on the complications of atherosclerosis. Without question, however, the clinical field of vascular surgery encompasses a number of areas other than clinical vasospasm as exemplified by Raynaud's syndrome. At the Clinical Research Center at the Oregon Health Sciences University, during the past 20 years the vascular surgery unit has maintained an active research program in Raynaud's syndrome and to date has enrolled and longitudinally followed more than 1000 patients with this affliction. There has been an opportunity to participate in the long-term management of this large population with emphasis both on natural history and vascular laboratory diagnosis and treatment. Raynaud's syndrome is a condition characterized by episodic digital ischemia in response to cold or emotional stimuli. The incidence is greater in women, and it is more frequent in areas with a cool, damp climate. Raynaud's usually affects the hands and fingers, but it may affect the feet and toes as well. The classical Raynaud's attack is tricolor and consists of blanching of the digits resulting from cessation of arterial flow, then cyanosis upon rewarming. This is followed by reactive hyperemia, which causes the digits to turn red. Raynaud's syndrome is classified into two groups: vasospastic or obstructive. Vasospastic Raynaud's is generally cold-induced. Nicotine, stress, and caffeine are associated with vasospasm. Obstructive Raynaud's is observed in association with other diseases such as connective tissue disorders, atherosclerosis, traumatic occlusion, Buerger's disease, and occupational related disorders. The diagnosis of Raynaud's is based on differentiating between vasospasm and obstruction and detecting the presence of associated disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1993

On the plausibility of the clonal expansion theory of the immune system in terms of the combinatorial possibilities of amino-acids in antigen and self-tolerance.

The clonal expansion theory of the immune system was first proposed over 30 years age (Jerne, 1955; Burnet, 1959). It still forms the basis of current thinking about the immune system. It was not obvious to the authors of this paper that the combinatorial possibilities of the 20 available amino acids in antigen peptides could result in a system that could distinguish successfully between self and foreign antigen, utilizing only the trial and error method proposed by the clonal expansion theory. In this paper it is demonstrated that the theory is credible on this issue, at least with respect to major histocompatibility complex (MHC) restricted antigen recognition, and that the very high proportion of immature lymphocytes that die in the thymus is consistent with the theory.

Amino Acids↗
PubMed1993

Prostitution and risk of HIV: female prostitutes in London.

OBJECTIVE: To measure the prevalence of HIV and to describe established risk factors in female prostitutes. DESIGN: A cross sectional survey. SETTING: A genitourinary medicine clinic, streets, and magistrates' courts in London. SUBJECTS: 280 female prostitutes recruited between April 1989 and August 1991. MAIN OUTCOME MEASURES: Infection with HIV-1, reported risk behaviours, and prevalence of sexually transmitted infections. RESULTS: 228 of the women had HIV tests, and two (0.9% (95% confidence interval 0% to 2.1%)) were infected with HIV-1. Reported use of condoms was high for commercial clients and low for non-paying partners: 98% (251/255) of women used condoms with all clients and 12% (25/207) with non-paying partners for vaginal intercourse. Twenty two women were current or past injecting drug users. Of the 193 women examined for sexually transmitted infections, 27 had an acute infection (gonorrhoea, chlamydia, trichomonas, or primary genital herpes) at the time of interview. Infection was associated with younger age and increasing numbers of non-paying sexual partners, but not with duration of prostitution, numbers of clients, or reports of condom failures. When age and numbers of non-paying partners were analysed by logistic regression they remained significantly associated with sexually transmitted infections. CONCLUSIONS: A large and diverse sample of prostitutes had a low prevalence of infection with HIV and high levels of use of condoms in commercial sex. There was a significant risk of other sexually transmitted infections associated with prostitutes' non-commercial sexual relationships, in which unprotected sex is common. Interventions to reduce the risk of sexually transmitted infections in prostitutes should address both commercial and non-commercial sexual partnerships.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Neisseria gonorrhoeae isolated at St. Mary's Hospital London, 1980-91.

OBJECTIVE: To describe and discuss the trends in the isolation of Neisseria gonorrhoeae from patients attending the Genitourinary Medicine Clinic at St. Mary's Hospital, Paddington, London between 1980 and 1991. DESIGN: A retrospective study of the total number of gonococci isolated over an eleven year period was performed. In addition, for the years 1988-1991 the number of isolates from homosexual men was analysed by age of the patient, site of infection and HIV antibody status of the patient. RESULTS: The total number of N. gonorrhoeae isolates identified declined markedly between 1980 and 1989 from 3670 to 750 isolates. Over the same time period the number of specimens screened for N. gonorrhoeae fell by 50%. In 1990 there was an increase in N. gonorrhoeae isolates but this was not maintained, and in 1991 the number of N. gonorrhoeae fell to its lowest level of 638 isolates. The decrease since 1980 occurred in both men and women although the number of rectal isolates from men showed a steeper decline reaching its lowest level of 24 isolates in 1988. The number of rectal isolates from homosexual men has since increased with a peak in 1990. Many of the infections among homosexual men occurred in older men and included insignificant number of patients who were HIV positive. CONCLUSION: Gonorrhoea among attenders at St. Mary's Hospital has declined dramatically since 1980 following trends reported from much of Europe. The increase in gonococcal isolates since 1989 and the peak in 1990 are unexplained but are coincident with a higher number of isolates from homosexual men.

Adult↗
PubMed1993

Late functional results after surgical closure of acquired ventricular septal defect.

To assess the longer term outlook for patients who have undergone surgery for acquired (postinfarction) ventricular septal defect, we interviewed and studied 60 survivors from a single regional cardiac center between 3 and 144 months after the operation. Including the patients who died within 1 month of the operation, the 5-, 10-, and 14-year survivals (with standard errors) were 69% (65% to 74%), 50% (44% to 57%), and 37% (27% to 46%). Eighty-two percent of patients were in New York Heart Association class I or II. Ten patients (17%) had a persisting but not hemodynamically significant ventricular septal defect. Mean left ventricular ejection fraction was reduced at 0.39 (standard deviation 0.15), but this did not correlate with either New York Heart Association class or exercise tolerance. Twenty-eight patients (47%) had asymptomatic arrhythmias (17 with ventricular premature beats). Angina and other medical problems were not prevalent.

Aged↗