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Biomedical subjects

G Hart

Publications and source records attributed to G Hart.

At least 19 recordsLinked to original sources
PubMed2006

Impact of a theoretically based sex education programme (SHARE) delivered by teachers on NHS registered conceptions and terminations: final results of cluster randomised trial.

OBJECTIVE: To assess the impact of a theoretically based sex education programme (SHARE) delivered by teachers compared with conventional education in terms of conceptions and terminations registered by the NHS. DESIGN: Follow-up of cluster randomised trial 4.5 years after intervention. SETTING: NHS records of women who had attended 25 secondary schools in east Scotland. PARTICIPANTS: 4196 women (99.5% of those eligible). INTERVENTION: SHARE programme (intervention group) v existing sex education (control group). MAIN OUTCOME MEASURE: NHS recorded conceptions and terminations for the achieved sample linked at age 20. RESULTS: In an "intention to treat" analysis there were no significant differences between the groups in registered conceptions per 1000 pupils (300 SHARE v 274 control; difference 26, 95% confidence interval -33 to 86) and terminations per 1000 pupils (127 v 112; difference 15, -13 to 42) between ages 16 and 20. CONCLUSIONS: This specially designed sex education programme did not reduce conceptions or terminations by age 20 compared with conventional provision. The lack of effect was not due to quality of delivery. Enhancing teacher led school sex education beyond conventional provision in eastern Scotland is unlikely to reduce terminations in teenagers. TRIAL REGISTRATION: ISRCTN48719575 [controlled-trials.com].

Abortion, Induced↗
PubMed2006

Greater antiarrhythmic activity of acute 17beta-estradiol in female than male anaesthetized rats: correlation with Ca2+ channel blockade.

BACKGROUND AND PURPOSE: Female sex hormones may protect pre-menopausal women from sudden cardiac death. We therefore investigated the effects of the main female sex hormone, 17beta-estradiol, on ischaemia-induced cardiac arrhythmias and on the L-type Ca2+ current (ICaL). EXPERIMENTAL APPROACH: In vivo experiments were performed in pentobarbital-anaesthetized rats subjected to acute coronary artery occlusion. ICaL was measured by the whole-cell patch-clamp technique, in rat isolated ventricular myocytes. KEY RESULTS: Acute intravenous administration of 17beta-estradiol as a bolus dose followed by a continuous infusion, commencing 10 min before coronary artery occlusion, had dose-dependent antiarrhythmic activity. In female rats 300 ng kg(-1) + 30 ng kg(-1) min(-1) 17beta-estradiol significantly reduced the number of ventricular premature beats (VPBs) and the incidence of ventricular fibrillation (VF). A ten fold higher dose of 17beta-estradiol was required to cause similar effects in male rats. In vitro 17beta-estradiol reduced peak ICaL in a concentration-dependent manner. The EC50 was ten-fold higher in male myocytes (0.66 microM) than in females (0.06 microM). CONCLUSIONS AND IMPLICATIONS: These results indicate that 17beta-estradiol has marked dose-dependent antiarrhythmic activity that is greater in female rats than in males. A similar differential potency in blocking ICaL in myocytes from female and male rats can account for this effect. This provides an explanation for the antiarrhythmic activity of 17beta-estradiol and gender-selective protection against sudden cardiac death.

Anesthesia↗
PubMed2005

Development of a novel home sperm test.

BACKGROUND: The majority of men find the production of a semen sample an embarrassing and stressful experience. Consequently, the availability of an over-the-counter home sperm test, which would reliably and accurately allow the patient to obtain an assessment of fertility potential at their convenience, would be a major benefit. Our objective was to develop and evaluate a home sperm test that provides a visual estimate of the concentration of progressively motile sperm in a semen sample. METHODS: Three particular challenges are described (i) developing a visualization system; (ii) optimization of the detection limit; and (iii) controlling variation due to changes in ambient temperature. The accuracy of the device was tested against two reference methods: computer-assisted sperm analysis (CASA) and a hyaluronate migration test (HMT). RESULTS: In 129 semen samples, where both reference methods agreed (positive or negative), the accuracy of the device was 95%. The observed likelihood ratio of 8.8 indicated that a sample showing a red line in the device was over eight times more likely to have a positive (normal) result in CASA and HMT than a sample without a red line. CONCLUSIONS: The final device provides a visual estimate of the concentration of progressively motile sperm in a semen sample using a test that is completed within approximately 1 h of production of the sample and can be used by the man in the comfort of his own home.

Humans↗
PubMed2005

The importance of irradiance and area in neonatal phototherapy.

BACKGROUND: Despite a long period of development, there are still considerable variations in the spectral output, the levels of irradiance, and irradiated area provided by commercial phototherapy systems. These variations depend on the types and output of the lamps used to produce the phototherapy, along with the design of the systems, and principally on whether the phototherapy is provided from overhead or underneath. OBJECTIVE: To see whether commercially available phototherapy systems produce sufficient irradiance over the surface area of the neonate. METHODS: Surface plots of the output irradiance were made on a number of systems and used to calculate the effective irradiance on the surface of a premature or term baby, using mapped outlines. RESULTS: A 10-fold difference in peak central irradiances was found between the systems tested, with a fourfold to fivefold difference in effective irradiance to the baby surfaces. Although work published over 20 years ago showed that levels of irradiance should reach 2 mW/cm2 to achieve optimal effectiveness, some of the commercial systems tested do not appear to achieve this level. CONCLUSION: Purchasers of neonatal phototherapy systems need to take into account whether the systems will produce sufficient irradiance over the area to ensure maximal effect, to keep the treatment time to a minimum.

Equipment Design↗
PubMed2005

Plasma filtration.

Therapeutic plasma exchange (TPE) or plasmapheresis involves the separation of plasma from whole blood. In so doing, plasma-borne humoral disease mediators are removed from the body. This can attenuate the course and severity of the underlying disease. Diseases that can be treated with TPE are classified into the following categories: (1) endocrinological, (2) neurological, (3) renal/rheumatological, and (4) haematological. TPE is adjuvant in most of these settings. Disease-specific pharmacological treatment remains the cornerstone of treatment in many of these conditions. Plasma separation can be achieved with either (1) centrifugation (CF) or (2) membrane plasma filtration (PF). The latter is the focus of this review. It can be performed using either a continuous renal replacement therapy (CRRT) or haemodialysis (HD) machine. Standard plasma filtration has also been modified to incorporate sorbent technology which obviates the need for plasma volume replacement fluids. Larger clinical issues such as timing of initiation and intensity of therapy are examined.

Autoimmune Diseases↗
PubMed2005

A before and after trial of the effect of a high-dependency unit on post-operative morbidity and mortality.

OBJECTIVE: It has been suggested that the availability of a high-dependency unit (HDU), to facilitate graded admission to, and discharge from, an intensive care unit (ICU), might decrease post-operative morbidity. We wished to determine whether the addition of a 4-bed HDU to a tertiary 17-bed ICU facility at a University-affiliated hospital would decrease post-operative morbidity and mortality. PATIENTS AND METHODS: A prospective controlled before-and-after trial was performed with the opening of a 4-bed HDU. Consecutive patients admitted to hospital for major surgery during a 4-month control (pre-HDU) phase and during a 4-month intervention (HDU) phase were studied for the incidence of serious adverse events (SAEs), mortality after major surgery and mean duration of hospital stay. RESULTS: There were 1319 operations performed in 1125 patients during the pre-HDU period and 1369 operations performed in 1127 patients during the HDU period. During the HDU period there was an excess in unscheduled surgery cases (674 during HDU vs. 531 during the pre-HDU period; p < 0.0001). In the pre-HDU period, there were 414 SAEs in 190 patients compared with 456 SAEs in 209 patients during the HDU period (NS). There were no significant changes in any of the individual SAEs measured except for the incidence of post-operative acute pulmonary edema, which increased from 19 cases to 46 during the HDU period (p = 0.028). This increase was associated with a greater number of patients requiring re-intubation (52 vs. 75 cases; p = 0.044). The introduction of an HDU had no effect on mortality (80 deaths vs. 76; NS) and failed to reduce mean hospital length of stay (21.8 vs. 24 days; NS). CONCLUSIONS: The introduction of a 4-bed HDU in a teaching hospital was associated with a marked increase in unscheduled surgery and failed to reduce the incidence of post-operative SAEs, post-operative mortality, and mean duration of hospital stay.

Journal Article↗
PubMed2004

Use of gay Internet sites and views about online health promotion among men who have sex with men.

In May-June 2002, 4,974 men who have sex with men (MSM), average age 31 years, completed a self-administered questionnaire online accessed through two popular gay Internet sites in the UK (gaydar and gay.com UK). Most men were white (95%), employed (83%), lived in the UK (91%) and self-identified as gay (85%). Nearly half (46%) had not been tested for HIV, while 6% said they were HIV-positive. One-third (31%) reported high-risk sexual behaviour in the previous three months, i.e. unprotected anal intercourse with a partner of unknown or discordant HIV status. Nearly all the men (82%) had looked for a sexual partner on the Internet and three-quarters had been doing so for more than a year. Almost half the men (47%) said they preferred to meet men through the Internet rather than in bars or other 'offline' venues. Although nearly 40% of men said the most important reason for using these Internet sites was to find sexual partners, a further 17% said they primarily used them to have contact with other men, 16% because they were bored, 12% for entertainment, 4% because they were lonely and 3% because they were addicted to it. The majority of men in this survey had favourable attitudes towards online health promotion. Most men thought that Internet sites should allow health workers into chat-rooms (75%); would click on a banner to find out about sexual health (78%); and said if they met a health worker in a chat-room they would find out what they had to say (84%). In multivariate analysis, being HIV-positive, older age and high-risk sexual behaviour were all independently associated with an increased frequency of using the Internet to look for sex (p<0.05). The Internet has emerged as an important meeting place for men who have sex with men. As online HIV prevention initiatives are developed it will be important to monitor the extent to which the favourable attitudes seen here are reflected in preventive behaviours.

Adult↗
PubMed2004

Reflecting on the experience of interviewing online: perspectives from the Internet and HIV study in London.

This paper considers some of the strengths and weaknesses of conducting synchronous online interviews for qualitative research. It is based on a study among gay/bisexual men that used both qualitative and quantitative methods to explore the association between seeking sex through the Internet and HIV transmission risk. Between June 2002 and January 2004, 128 gay/bisexual men living in London were interviewed one-to-one by the first author (MD) about their experience of using the Internet to find sexual partners and negotiating condom use for anal sex. Thirty-five men were interviewed online, while 93 were interviewed face-to-face (i.e. offline). This paper draws on MD's experience of conducting these interviews--both online and face-to-face. Synchronous online interviews have the advantage of being cheap, convenient and attractive to people who do not like face-to-face interviews. However, some of the social conventions and technical limitations of computer-mediated-communication can introduce ambiguity into the online dialogue. To minimize this ambiguity, both interviewer and interviewee have to edit their online interaction. One of the distinctive features of the online interview is that it emerges as a form of textual performance. This raises fundamental questions about the suitability of the synchronous online interview for exploring sensitive topics such as risky sexual behaviour.

Adult↗
PubMed2004

An update and guidance on narrowband ultraviolet B phototherapy: a British Photodermatology Group Workshop Report.

Summary These guidelines for use of narrowband (TL-01) ultraviolet B have been prepared for dermatologists by the British Photodermatology Group on behalf of the British Association of Dermatologists. They present evidence-based guidance for treatment of patients with a variety of dermatoses and photodermatoses, with identification of the strength of evidence available at the time of preparation of the guidelines, and a brief overview of background photobiology.

Combined Modality Therapy↗
PubMed2004

Trends in sexual behaviour among London homosexual men 1998-2003: implications for HIV prevention and sexual health promotion.

OBJECTIVES: To examine changes in sexual behaviour among London homosexual men between 1998 and 2003 by type and HIV status of partner. METHODS: Homosexual men (n=4264) using London gyms were surveyed annually between 1998 and 2003 (range 498-834 per year). Information was collected on HIV status, unprotected anal intercourse (UAI) in the previous 3 months, and type of partner for UAI. High risk sexual behaviour was defined as UAI with a partner of unknown or discordant HIV status. RESULTS: Between 1998 and 2003, the percentage of men reporting high risk sexual behaviour with a casual partner increased from 6.7% to 16.1% (adjusted odds ratio (AOR) 1.36 per year, 95% confidence interval (CI) 1.26 to 1.46, p <0.001). There was no significant change in the percentage of men reporting high risk sexual behaviour with a main partner alone (7.8%, 5.6%, p=0.7). These patterns were seen for HIV positive, negative and never tested men alike regardless of age. The percentage of HIV positive men reporting UAI with a casual partner who was also HIV positive increased from 6.8% to 10.3% (AOR 1.27, 95% CI 1.01 to 1.58, p <0.05). CONCLUSION: The increase in high risk sexual behaviour among London homosexual men between 1998 and 2003 was seen only with casual and not with main partners. STI/HIV prevention campaigns among London homosexual men should target high risk practices with casual partners since these appear to account entirely for the recent increase in high risk behaviour.

Adult↗
PubMed2003

A topographical study of mechanical and electrical properties of single myocytes isolated from normal guinea-pig ventricular muscle.

Major regional differences in the electrical properties of myocytes from ventricular muscle have been described previously, on the basis of samples taken from a maximum of three regions in each heart. In order to define the topographical basis for such differences, we studied the electrical and mechanical properties of single myocytes isolated from 20 regions throughout the ventricles in the normal guinea-pig heart. Single myocytes were isolated using an enzymatic dispersion method, and were studied under conditions that were close to physiological. Cell capacitance and action potentials were recorded using the switch-clamp technique, and cell length and evoked shortening were measured using a photodiode array system. In the left ventricular free wall, mid-myocardial cells were longer and had greater capacitative surface area than surface myocytes. There were transmural but not longitudinal differences in APD90 (action potential duration to 90% repolarization), with the longest APD90 in subendocardial and the shortest in subepicardial myocytes. We found a septum-left ventricular free wall-right ventricular free wall gradient, with the longest APD90 in the septum and the shortest in the right ventricular free wall. The regional distribution of APD90 was closely mirrored by relaxation time. Peak cell shortening was greater in subendocardial myocytes than in subepicardial myocytes in the left ventricular free wall, and in myocytes from the left side of the septum compared with the right. We concluded that the regional distribution of APD is closely and inversely related to the sequence of ventricular depolarization, and that the regional variations in cell shortening amplitude are related principally to reported regional variations in wall stress.

Action Potentials↗
PubMed2003

Exercise-induced cardiac hypertrophy: a substrate for sudden death in athletes?

Cardiac hypertrophy is a general term signifying an increase in cardiac mass in response to applied stress. In mild, early hypertrophy, cardiac myocyte contractile performance may be normal or enhanced, whereas in severe hypertrophy associated with cardiac failure, myocyte contraction is reduced in amplitude and increased in duration. In contrast to the varied contractile response, the duration of electrical excitation shows similar changes in both mild and severe hypertrophy. Action potential duration in mid-myocardial and sub-epicardial layers is increased, which is associated with ventricular arrhythmias (in a similar manner to the long QT syndromes from other causes), based on afterdepolarizations and enhanced automaticity. Single-cell studies following exercise training in animal models show that exercise-induced cardiac hypertrophy displays features similar to mild, compensated hypertrophy from other causes. Developed shortening of unloaded single cells is increased or unchanged, and developed force in single myocytes is enhanced. Action potential duration is increased, apart from in the sub-endocardial layer. As with mild hypertrophy from other causes, this will be pro-arrhythmic because of altered dispersion of repolarization and enhanced automaticity. Major abnormalities of the ECG in man include frequent and complex ventricular ectopy, ST segment changes and prolongation of repolarization. In this review a case is presented for regarding exercise-induced cardiac hypertrophy as being no different from mild cardiac hypertrophy resulting from other, pathological causes. The cellular electrophysiological changes are sufficient to account for many of the abnormalities of the ECG, including high-grade ventricular ectopy. Sudden death in trained athletes who have no evidence of specific heart disease may be a direct consequence of cardiac hypertrophy and altered repolarization.

Adaptation, Physiological↗
PubMed2001

Qualitative analysis of psychosocial impact of diagnosis of Chlamydia trachomatis: implications for screening.

OBJECTIVES: To investigate the psychosocial impact for women of a diagnosis of Chlamydia trachomatis and discuss the implications for the proposed UK chlamydia screening programme. DESIGN: Qualitative study with semistructured interviews. Interview transcripts analysed to identify recurrent themes. PARTICIPANTS: Seventeen women with a current or recent diagnosis of chlamydia. SETTING: A family planning clinic and a genitourinary medicine clinic in Glasgow. RESULTS: Three themes were identified: perceptions of stigma associated with sexually transmitted infection, uncertainty about reproductive health after diagnosis, and anxieties regarding partner's reaction to diagnosis. Most women had not previously perceived sexually transmitted infections as personally relevant; this was a function of stereotypical beliefs about who was "at risk" of sexually transmitted infection. These beliefs were pervasive and negatively affected reactions to diagnosis and produced anxiety about disclosure of the condition to others (particularly sexual partners) and future reproductive morbidity. This anxiety, given the uncertain natural history of chlamydia, may prove difficult to dispel. CONCLUSIONS: There are three primary areas of concern for women after a diagnosis of chlamydia which need to be examined in the proposed screening programme. Information provided should normalise and destigmatise chlamydial infection and positively promote genitourinary medicine services. Support services should be available because notification of partner can cause anxiety. Uncertainty about future reproductive morbidity may be inevitable; staff providing screening will require guidance in providing advice under such conditions.

Adult↗
PubMed2001

Histological and immunological parameters to predict treatment outcome of Helicobacter pylori eradication in low-grade gastric MALT lymphoma.

Helicobacter pylori eradication is generally accepted as the first choice of treatment for stage IE low-grade gastric MALT lymphoma (mucosa-associated lymphoid tissue-type lymphoma). Treatment failure may be attributed to the extent of the disease and to progression into an antigen-independent phase. This study assessed the value of morphological grading and the expression of the co-stimulatory markers CD40, CD80 and CD86 and their ligands to predict clinical outcome in 23 consecutive low-grade MALT lymphoma patients treated with H. pylori eradication. Complete regression was achieved in 13/23 patients (56%), partial regression in two (9%), and no response in eight (35%). Histological grading was highly predictive of clinical response, especially in stage IE(1) patients, with complete remissions in 10/12 tumours with purely low-grade (type A) morphology and 1/8 tumours with increased numbers of blasts (type B) (p=0.0046) and was related to the expression of costimulatory markers (p=0.0061). Moreover, CD86 as a single marker proved to be of predictive value for treatment outcome (p=0.0086). These results suggest that morphological grading and immunological criteria can be defined to recognize the transition into the antigen-independent phase of gastric MALT-NHL. In addition to clinical stage, these critera may in future serve as a practical pathological guide to the choice of therapy.

Adult↗
PubMed2001

Heterosexism and homophobia in Scottish school sex education: exploring the nature of the problem.

This paper focuses on instances of heterosexism and homophobia, as well as examples of good practice in sex education, observed in 25 Scottish schools. Possible reasons for why good practice is not more widespread are explored. Qualitative and quantitative data are presented. Various constraints to good practice are identified by teachers, and are discussed in the context of survey data on pupil attitudes towards same-sex sexual relationships, and on teacher confidence in teaching about homosexuality.

Attitude↗