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Biomedical subjects

A D Grant

Publications and source records attributed to A D Grant.

At least 19 recordsLinked to original sources
PubMed2007

Establishing a workplace antiretroviral therapy programme in South Africa.

Ways to expand access to antiretroviral treatment (ART) in low income settings are being sought. We describe an HIV care programme including ART in an industrial setting in South Africa. The programme uses guidelines derived from local and international best practice. The training component aims to build capacity among health care staff. Nurses and doctors are supported by experienced HIV clinicians through telephone consultation and site visits. Patients undergo a three-stage counselling procedure prior to starting ART. Drug regimens and monitoring are standardised and prophylaxis against opportunistic infections (isoniazid and cotrimoxazole) is offered routinely. Laboratory and pharmacy services, using named-patient dispensing, are centralized. The programme is designed to ensure that data on clinical and economic outcomes will be available for programme evaluation. Between November 2002-December 2004, ART delivery has been established at 70 ART workplace ART sites. The sites range from 200 to 12000 employees, and from small occupational health clinics and general practitioner rooms to larger hospital clinics. During this period, 2456 patients began ART. Of those on treatment for at least three months, 1728 (78%) have been retained on the programme and only 38 (1.7%) patients have failed the first-line ART regimen. This model for delivery of ART is feasible and successful in an industrial setting. The model may be generalizable to other employment health services in settings of high HIV prevalence, and as a model for implementing ART in other types of health-care settings.

Anti-HIV Agents↗
PubMed2006

Screening for tuberculosis prior to isoniazid preventive therapy among HIV-infected gold miners in South Africa.

SETTING: Human immunodeficiency virus (HIV) clinic for employees of a gold mine, Free State, South Africa. OBJECTIVE: To evaluate the process of screening for active tuberculosis (TB) prior to commencing TB preventive therapy in HIV-infected individuals. DESIGN: Cross-sectional study comparing performance of various combinations of screening tests for TB against a gold standard diagnosis of TB based on symptoms, chest radiograph (CXR), sputum microscopy and culture. RESULTS: Of 899 individuals, 44 (4.9%) had TB. The most sensitive symptom combination (59.1%) was any of night sweats, new or worsening cough or reported weight loss; measured weight loss > 5% or abnormal CXR increased sensitivity to 90.9%. Sputum microscopy did not increase sensitivity further, but including World Health Organization HIV clinical staging or CD4 count did. As the specificity of all these combinations was low, many individuals required further investigation to rule out TB. TB prevalence was high (11.7%) among individuals with a CD4 count < 200/mm3. CONCLUSION: CXR greatly increased the sensitivity of screening for TB in this population. Sputum microscopy conferred no additional benefit among asymptomatic patients with a normal CXR. The high prevalence of TB amongst those with a low CD4 count underlines the importance of screening for active TB prior to commencing TB preventive therapy, and before antiretroviral therapy.

Adult↗
PubMed2006

Perceptions and experiences of tuberculosis among African patients attending a tuberculosis clinic in London.

SETTING: Little is known of the social and cultural issues influencing the uptake of and attitudes to tuberculosis (TB) care by people of African extraction living in the UK. OBJECTIVE: To describe the perceptions and experiences of African patients with TB in London, focusing on issues relating to diagnosis, treatment adherence and stigma. DESIGN: Qualitative study using in-depth interviews. RESULTS: Misinterpretation of early symptoms led to delays in seeking health care. Although half of the respondents reported denial of the diagnosis, they reported good treatment adherence, noting the role of TB specialist nurses in promoting adherence. Respondents felt stigmatised by the diagnosis, although actual experiences of stigma were rare. Experience of TB in a known person mitigated stigma. Human immunodeficiency virus (HIV) disease was perceived to have worsened TB stigma, and most patients offered HIV testing initially declined, fearing stigmatisation and poor illness outcomes if positive. CONCLUSIONS: Awareness of TB can be improved among migrants at high risk of developing the disease and among health professionals. Counselling around HIV testing for TB patients must take their beliefs into account if a high uptake of testing is to be achieved.

Adult↗
PubMed2005

Enhanced vascular responses to adrenomedullin in mice overexpressing receptor-activity-modifying protein 2.

Adrenomedullin (AM) levels are elevated in cardiovascular disease, but little is known of the role of specific receptor components. AM acts via the calcitonin receptor-like receptor (CLR) interacting with a receptor-activity-modifying protein (RAMP). The AM1 receptor is composed of CLR and RAMP2, and the calcitonin gene-related peptide (CGRP) receptor of CLR and RAMP1, as determined by molecular and cell-based analysis. This study examines the relevance of RAMP2 in vivo. Transgenic (TG) mice that overexpress RAMP2 in smooth muscle were generated. The role of RAMP2 in the regulation of blood pressure and in vascular function was investigated. Basal blood pressure, acute angiotensin II-raised blood pressure, and cardiovascular properties were similar in wild-type (WT) and TG mice. However, the hypotensive effect of IV AM, unlike CGRP, was enhanced in TG mice (P<0.05), whereas a negative inotropic action was excluded by left-ventricular pressure-volume analysis. In aorta relaxation studies, TG vessels responded in a more sensitive manner to AM (EC50, 8.0+/-1.5 nmol/L) than WT (EC50, 17.9+/-3.6 nmol/L). These responses were attenuated by the AM receptor antagonist, AM(22-52), such that residual responses were identical in all mice. Remaining relaxations were further inhibited by CGRP receptor antagonists, although neither affected AM responses when given alone. Mesenteric and cutaneous resistance vessels were also more sensitive to AM in TG than WT mice. Thus RAMP2 plays a key role in the sensitivity and potency of AM-induced hypotensive responses via the AM1 receptor, providing evidence that this receptor is a selective target for novel therapeutic approaches.

Adrenomedullin↗
PubMed2005

Evaluation of antiretroviral therapy (ART)-related counselling in a workplace-based ART implementation programme, South Africa.

Counselling about antiretroviral therapy (ART) is thought important to prepare patients for treatment and enhance adherence. A workplace-based HIV care programme in South Africa instituted a three-step ART counselling protocol with guidelines prompting issues to be covered at each step. We carried out an early evaluation of ART counselling to determine whether patients understood key information about ART, and the perceptions that patients and health care professionals (HCP) had of the process. Among 40 patients (median time on ART 83 days), over 90% answered 6/7 HIV/ART knowledge-related questions correctly. 95% thought counselling sessions were good. 93% thought ongoing counselling was important. Recommendations included the need for continuing education about HIV/ART, being respectful, promoting HIV testing and addressing the issues of infected partners and stigma. 24 participating HCP identified additional training needs including counselling of family and friends, family planning, sexually transmitted infections and running support groups. 90% of HCP thought that counselling guidelines were helpful. The programme appears to be preparing patients well for ART. Counselling should be offered at every clinic visit. Counselling guidelines were a valuable tool and may be useful elsewhere. The evaluation helped to assess the quality of the programme and to suggest areas for improvement.

Adult↗
PubMed2004

The calcitonin gene-related peptide (CGRP) receptor antagonist BIBN4096BS blocks CGRP and adrenomedullin vasoactive responses in the microvasculature.

Calcitonin gene-related peptide (CGRP) is a potent microvascular dilator neuropeptide that is considered to play an essential role in neurogenic vasodilatation and in maintaining functional integrity in peripheral tissues. We have examined the effect of the nonpeptide CGRP antagonist BIBN4096BS on responses to CGRP and the structurally related peptide adrenomedullin, AM, in murine isolated aorta and mesentery preparations, and in the cutaneous microvasculature in vivo. We show for the first time that BIBN4096BS is an effective antagonist of CGRP and AM responses in the murine mesenteric and cutaneous microvasculature, and of CGRP in the murine aorta. After local administration, BIBN4096BS selectively inhibits the potentiation of microvascular permeability in the cutaneous microvasculature by CGRP and AM, with no effect on responses induced by other microvascular vasodilators. BIBN4096BS reversed both newly developed and established vasoactive responses induced by CGRP. The ability of CGRP to potentiate plasma extravasation was lost when coinjected with compound 48/80 (where mast cells would be activated to release proteases), but regained when soybean trypsin inhibitor was coinjected with compound 48/80. These results demonstrate that BIBN4096BS is a selective antagonist of responses induced by CGRP and AM in the mouse microvasculature, and CGRP in the mouse aorta. The ability of BIBN4096BS to block an established CGRP microvascular vasodilatation indicates that the sustained vasodilator activity of CGRP is due to the retention of the active intact peptide and the continued involvement of the CGRP receptor.

Adrenomedullin↗
PubMed2004

Feasibility and acceptability of a specialist clinical service for HIV-infected mineworkers in South Africa.

Occupational settings offer an ideal opportunity to provide preventive health services for HIV-infected workers. A specialized clinic was established in a mining hospital in the Free State, South Africa, with the primary aim of delivering preventive therapy such as isoniazid to those at high risk of tuberculosis (individuals with HIV infection or silicosis), and cotrimoxazole to those at highest risk for opportunistic infections. The clinic design has taken regard of the importance of minimizing stigma, protecting confidentiality, monitoring potential side effects, supporting adherence and identification of prophylaxis failure. The clinic opened in April 1999 and, by August 2001, 1773 patients had attended at least once; 1762 are HIV-infected and 11 have silicosis. Of those with HIV infection, most were asymptomatic at their first visit. The clinic has achieved high acceptability: 99% of persons who were actively recruited to the service agreed to attend. The number still attending after a median of 13 months from recruitment was 1,270 (72%) and only 48 (2.7%) have declined continued attendance. Most losses were due to termination of employment unrelated to a medical condition. The clinic has already been successfully replicated in two other regions of the mining health service in South Africa and provides a model for workplace HIV clinical services that could be used for implementation of further interventions such as antiretroviral therapy.

AIDS-Related Opportunistic Infections↗
PubMed2003

Attitudes to HIV voluntary counselling and testing among mineworkers in South Africa: will availability of antiretroviral therapy encourage testing?

We conducted a study to identify attitudes that influence uptake of HIV voluntary counselling and testing (VCT) amongst gold mine workers in South Africa; 105 healthy men were interviewed. The level of basic knowledge of HIV was high, but reported awareness of the extent of HIV infection in the workforce and perceived personal risk of HIV infection was low. Health issues were considered the most important indication for HIV testing and one-third had been tested. Fear of testing positive for HIV and the potential consequences, particularly stigmatization, disease and death, were the major identified barriers to VCT. Half of the participants felt workplace education programmes needed to be improved to promote VCT access. Twenty-six per cent became more favourably inclined towards HIV testing in response to information on improvements that have been made to the confidentiality and convenience of the company's VCT service. Only 14% then indicated that they would be more likely to access VCT if antiretroviral therapy became available. A vigorous community education programme is essential if the introduction of ART is to be effective in promoting uptake of VCT.

Adult↗
PubMed2003

Lactic acidosis in HIV infected patients: a systematic review of published cases.

OBJECTIVE: To describe the clinical, epidemiological, and biochemical characteristics of published cases of lactic acidosis (LA) and to generate hypotheses concerning risk factors associated with this complication. METHODS: Systematic review of cases reported in the medical literature. RESULTS: 217 published cases were identified, 90 of which fulfilled the study definition and had sufficient individual data on potential risk factors to be included. The 90 patients had a mean age of 40.1 years (range 16-69) and 53% were female. All 90 patients were taking nucleoside reverse transcriptase inhibitors (NRTI) at the time of the episode. Among the 83 patients with details of their antiretroviral therapy (ART) regimen 51 patients were taking stavudine, 29 zidovudine, 27 didanosine, and 25 lamivudine. Around 50% of the patients had abdominal pain, nausea, or vomiting. Hepatic steatosis was consistently reported (53/90) and in 36 (68%) there was histological evidence. The case fatality rate was 48%. Six cases were rechallenged with NRTI and three developed a further LA episode. Using data on the numbers of HIV infected individuals receiving care in the United States, we estimate that the risk of LA could be 2.5 times higher for women than men. CONCLUSIONS: NRTI use and female sex appear to be risk factors for the development of LA. What other factors are involved is still not clear but might include duration of NRTI therapy, specific drug use, and genetic predisposition. A case-control study is needed to better define risk factors for severe LA.

Acidosis, Lactic↗
PubMed2002

Use of UNAIDS tools to evaluate HIV voluntary counselling and testing services for mineworkers in South Africa.

HIV voluntary counselling and testing (VCT) is now an integral part of many HIV care and control programmes. However, very little work has been done to assess the quality of VCT services. An evaluation of VCT services for mineworkers in Welkom, South Africa was conducted to assess client and counsellor satisfaction, the quality of the services and to identify barriers to uptake of VCT. A cross-sectional survey was carried out using tools developed by UNAIDS, consisting of semi-structured interviews and observation of counselling sessions. Twenty-two nurse counsellors and six community volunteers were interviewed. Twenty-four counselling sessions were observed and 24 client exit interviews were conducted. Although nine of the 22 nurse counsellors had only in-service rather than formal training for HIV counselling whereas all community volunteers had been formally trained, nurse counsellors demonstrated better interpersonal skills than did community volunteers. Both clients and counsellors identified fear of a positive result as a major barrier to HIV testing. Clients also raised concerns about confidentiality. UNAIDS evaluation tools were a feasible and an acceptable method of assessing VCT in this operational setting. The study identified areas where training needs to be strengthened and suggested ways of improving the services, and changes to the service have now been implemented in line with these recommendations.

Counseling↗
PubMed2002

Use of spoligotyping for accurate classification of recurrent tuberculosis.

The spoligotyping method has become an important tool for the tracking of Mycobacterium tuberculosis strains in different epidemiological settings. In this study, we demonstrate the ability of the spoligotyping technique to accurately determine the pathogenetic mechanism of recurrent disease. This methodology has advantages over conventional restriction fragment length polymorphism methods which may be useful in large-scale intervention studies.

Diagnostic Techniques and Procedures↗
PubMed2001

Lack of a significant effect of deletion of the tachykinin neurokinin-1 receptor on wound healing in mouse skin.

The tachykinin neurokinin-1 (NK(1)) receptor mediates the vasoactive effects of substance P and related members of the tachykinin family. Substance P acts via the NK(1) receptor to mediate increased microvascular permeability leading to oedema formation as confirmed in NK(1) receptor knockout mice. In addition there is evidence that neuropeptides such as substance P can have a modulatory effect on the wound-healing process. In this study male and female wild-type and NK(1) knockout mice were investigated for their comparative ability to induce acute oedema formation in response to topical application of capsaicin, as measured by the extravasation of intravenous radiolabelled-albumin, and wound healing in response to a cut, as measured by area of wound over the following days. Significant (P<0.001) oedema, approximately three-fold over basal, was induced by capsaicin in both male and female wild-type mice, an indicator of a similar responsiveness irrespective of sex. However, as expected, the oedema was not observed in the knockout mice. Wounding was achieved through a 1-cm full-thickness cut into the interscapular area of dorsal skin. Wound healing was then followed in two different protocols. The wound was left to heal naturally over 14 days in the first protocol and no significant changes in healing were observed in wild-type compared to knockout. In the second protocol, the skin was sutured open for the first 48 h, to prevent the elasticity of the skin from initiating a natural healing process through flap formation. This caused a significant increase in the area of the wound. Despite this, wounds in both wild-type and knockout mice healed in an identical manner that was complete after 17 days. In conclusion, it is shown that deletion of a functional NK(1) receptor has little effect on wound healing in response to a simple cut in mouse skin.

Animals↗
PubMed2001

Genomic dissection reveals locus response to stress for mammalian acetylcholinesterase.

The mammalian acetylcholinesterase (ACHE) locus was investigated using computational predictive methods and experiments of reverse transcription polymerase chain reaction (RT-PCR). Computational analysis identified two genes downstream to ACHE, an inversely oriented arsenite resistance gene homologue (ARS), and a novel previously unidentified gene (PIX), co-oriented with ACHE. Experimental evidence shows coregulation of murine ACHE and ARS following confined swim, indicating coordinated locus response to stress, that is possibly mediated by altered cholinergic neurotransmission.

Acetylcholine↗
PubMed2001

Preventing opportunistic infections among human immunodeficiency virus-infected adults in African countries.

The burden of human immunodeficiency virus (HIV)-related disease in sub-Saharan Africa continues to increase; providing adequate care for the huge number of people affected is a daunting task, especially given the limited resources available. Recent studies have shown that low-cost regimens can prevent some of the most important causes of HIV-related disease in African countries. Isoniazid preventive therapy can reduce the incidence of tuberculosis; priorities are to seek opportunities for implementation, to assess effectiveness under operational conditions, and to monitor its effect on resistance patterns. Cotrimoxazole was shown to be highly effective in reducing morbidity and mortality among individuals with symptomatic HIV disease in Côte d'Ivoire, and should be implemented where it is likely to be of benefit. Pneumococcal polysaccharide vaccine was disappointingly ineffective among HIV-infected Ugandan adults, but newer conjugate vaccines are becoming available that should be investigated. The benefit of these preventive regimens to the individual may be modest when compared with the effect of antiretroviral therapy. However, simple preventive therapies could reach a much wider population than is immediately feasible for expensive and complex antiretroviral regimens, and thus have the potential for substantial benefit at the population level. The availability of effective and affordable regimens to prevent HIV-related disease may also encourage people to seek HIV testing, combat denial, and help overcome the sense of powerlessness in countries where the HIV epidemic has hit hardest.

AIDS-Related Opportunistic Infections↗
PubMed2000

What a test for recent infection might reveal about HIV incidence in England and Wales.

BACKGROUND: A laboratory method has been developed that detects recent HIV infection and allows incidence to be estimated by testing single stored antibody-positive specimens. A theoretical exploration of the method's surveillance utility was carried out. METHODS: Using various data sources, HIV incidence rates were postulated. The confidence intervals (CI) for these postulated incidences were calculated using the expected number of recent infections for each postulated incidence, the actual number tested for HIV, and the known number of HIV-1 positives. A test for trend was used to determine when an important change in incidence could be recognized. RESULTS: If the incidence was 5% per annum (p.a.) in homosexual/bisexual men attending sexually transmitted diseases (STD) clinics in London, 64 recent infections would be expected in the 392 HIV-seropositive specimens and, if observed, would result in a 95% CI of 3.1-7.9% p.a. for the incidence rate. An incidence of 1% p.a. in pregnant women would be most unlikely as this would require detection of 193 recent infections, 26 more than the total 167 HIV-seropositive specimens found in 1997. In African women attending STD clinics in London, 30% of prevalent infections would be classified as recent if the incidence was 5% p.a. Further, if the incidence in homosexual/bisexual men were to fall by 50% over 3 years, a decrease of this magnitude would be recognized as significant within 2 years. CONCLUSIONS: The detuned assay will increase the information from HIV serosurveys even where prevalence and incidence are relatively low. Existing surveillance systems should be redesigned to take full advantage of the method.

Confidentiality↗
PubMed2000

A transcription-activating polymorphism in the ACHE promoter associated with acute sensitivity to anti-acetylcholinesterases.

Hypersensitivity to acetylcholinesterase inhibitors (anti-AChEs) causes severe nervous system symptoms under low dose exposure. In search of direct genetic origin(s) for this sensitivity, we studied six regions in the extended 22 kb promoter of the ACHE gene in individuals who presented adverse responses to anti-AChEs and in randomly chosen controls. Two contiguous mutations, a T-->A substitution, disrupting a putative glucocorticoid response element, and a 4-bp deletion, abolishing one of two adjacent HNF3 binding sites, were identified 17 kb upstream of the transcription start site. Allele frequencies for these mutations were 0.006 and 0.012, respectively, in 333 individuals of various ethnic origins, with a strong linkage between the deletion and the biochemically neutral H322N mutation in the coding region of ACHE. Heterozygous carriers of the deletion included a proband who presented with acute hypersensitivity to the anti-AChE pyridostigmine and another with unexplained excessive vomiting during a fourth pregnancy following three spontaneous abortions. Electromobility shift assays, transfection studies and measurements of AChE levels in immortalized lymphocytes as well as in peripheral blood from both carriers and non-carriers, revealed functional relevance for this mutation both in vitro and in vivo and showed it to increase AChE expression, probably by alleviating competition between the two hepatocyte nuclear factor 3 binding sites. Moreover, AChE-overexpressing transgenic mice, unlike normal FVB/N mice, displayed anti-AChE hypersensitivity and failed to transcriptionally induce AChE production following exposure to anti-AChEs. Our findings point to promoter polymorphism(s) in the ACHE gene as the dominant susceptibility factor(s) for adverse responses to exposure or to treatment with anti-AChEs.

Acetylcholinesterase↗