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Biomedical subjects

A Ashraf

Publications and source records attributed to A Ashraf.

At least 19 recordsLinked to original sources
PubMed2001

Myocardial infarction with normal coronary angiography compared with severe coronary artery disease without myocardial infarction: the crucial role of smoking.

BACKGROUND: Why do some patients suffer acute myocardial infarction (MI) despite angiographically normal coronary arteries (NL + MI) whereas others enjoy an acute MI-free life despite extensive three-vessel disease (3VD-MI)? The present study contrasts these two groups to identify some differences in the risk profile. METHODS: In 10,000 patients admitted to the cardiology service, a first MI was confirmed in 2356 patients, of whom 1609 underwent coronary angiography. In 77 patients with MI, coronary angiography was found to be entirely normal (NL + MI, 77/1609, 4.1%). These were contrasted to 123 patients with severe three-vessel coronary disease but no MI (3VD-MI). RESULTS: Patients with NL + MI were 13 years younger (42 +/- 8.3 vs 55 +/- 10.5, P < 0.05), with 33 patients (43%) under the age 40 years, in contrast to only 9 patients (7.3%) in the 3VD group being this age. Patients with NC + MI were more often current smokers (80.5% vs 29% in the 3VD group; P < 0.01). Patients with 3VD-MI were, on the other hand, more often diabetic (54% vs 9% in the NL + MI group; P < 0.01) and had a higher cholesterol level (5.6 +/- 1.1 vs 4.9 +/- 1.0 Mmol/l, P < 0.01) as well as a higher incidence of chronic stable angina (52% vs 22%; P < 0.01) and heart failure (6% compared with 0% in the NL + MI group). Sixty-one out of 77 (79%) NL + MI patients had a single risk factor, and in 87%, this was smoking alone. Diabetes mellitus was rare and never occurred alone in this group. CONCLUSION: In patients who suffer MI despite normal coronary angiography, smoking is a major risk factor: In contrast, in patients with extensive coronary artery disease on angiography but no MI, diabetes rather than smoking is the dominant risk factor. The findings of this study support the view that the risk factors for stable and unstable coronary artery disease are different, as reflected by the contrast of the above groups at the extremes of the spectrum. Smoking appears to be a major risk factor for acute MI (even with normal coronary angiography), whereas diabetes is a major risk factor for more severe but more stable coronary artery disease.

Adult↗
PubMed2000

Comparative quantification of diverse serotypes of HIV-1 in plasma from a diverse population of patients.

HIV-1 is characterised by extensive genetic variability encompassing at least 10 different phylogenetically related clades within the major group of HIV-1 subtypes. Most commercially available HIV-1 RNA plasma viral load assays have been optimised with clade B viruses and may yield misleadingly low RNA levels for nonclade B viruses that are increasingly found in Europe. In this study we compare the most recent versions of the Roche Amplicor HIV Monitor and the Chiron Quantiplex for ability to detect viraemia in a population of patients infected with a range of HIV-1 subtypes. EDTA-treated plasma was obtained from 206 patients. The Amplicor and Quantiplex assays were carried out in accordance with manufacturers' instructions. Results from 53/206 (25.7%) samples differed by >0.4 log between Amplicor 1.5 and Quantiplex 3.0. A >0.5 log and 1.0 log difference was detected between Amplicor 1.5 and Quantiplex 3.0 in 37/206 (17.9%) and 7/206 (3.4%) of samples, respectively. Overall, Amplicor 1.5 gave a median value of 0.22 log higher than Quantiplex 3.0. Discordant results were detected in 53 out of 206 (25.7%) samples. Of these 22 out of 123 (17.9%) samples were of UK origin, 18 out of 43 (41.9%) African, 1 out of 8 (12.5%) South American, 1 out of 6 (16.7%) North American, 4 out of 9 (44.4%) North European, 3 out of 11 (23.7%) South European and 3 out of 7 (42.3%) Asian samples, respectively. Serotyping revealed that discordant viral load results between Amplicor 1.5 and Quantiplex 3.0 occurred within samples from all subtypes (A-E). Despite the improvements made to both the Roche Amplicor and the Chiron Quantiplex assays discordant results were detected between the two assays in 25.7% of cases. In a substantial minority of patients there were major discrepancies between the two assays that were not explained by HIV subtype differences.

HIV Infections↗
PubMed1999

Drug susceptibility of Mycobacterium tuberculosis in a rural area of Bangladesh and its relevance to the national treatment regimens.

SETTING: Greater Mymensingh District, a rural area of Bangladesh, at the start of the National Tuberculosis Programme (NTP). OBJECTIVES: To determine the prevalence of initial and acquired drug resistance of Mycobacterium tuberculosis, and to assess the appropriateness of the NTP's standard regimens. DESIGN: Sampling of pre-treatment sputum from all newly registered smear-positive cases in five centres covering the area. Culture and susceptibility testing in a supra-national reference laboratory. RESULTS: Initial resistance to isoniazid (H) was 5.4%, and to rifampicin (R) 0.5%. Acquired H and R resistance were 25.9% and 7.4%, respectively. Multidrug resistance (MDR) was observed in one new case only and in 5.6% of previously treated patients. Changing the present NTP indication for retreatment regimen to one month of previous H intake would increase coverage of H-resistant cases from 52% to 89%, adding 6% to drug costs. CONCLUSION: The prevalence of drug resistance is surprisingly low in Bangladesh, but could rise with improving economic conditions. The NTP regimens for smear-positive cases are appropriate, all the more so since the human immunodeficiency virus is virtually absent. Indications for the retreatment regimen should be extended to include all patients treated for at least one month with any drug. The NTP regimen for smear-negative cases runs the risk of leading to MDR under present field conditions.

Adolescent↗
PubMed1998

[Robotics in neurosurgery: current status and future prospects].

Neurosurgery is in essence a field of application development for robots, based on multimodal image guidance. Specific motorized tools have already been developed and routinely applied in stereotaxy to position a probe holder or in conventional neurosurgery to hold a microscope oriented towards a given target. The potentialities of these approaches have triggered industrial developments which are now commercially available. These systems use databases, primarily coming from multimodal numerical images from X-ray radiology to magnetic resonance imaging. These spatially encoded data are transferred through digital networks to workstations where images can be processed and surgical procedures are pre-planned, then transferred to the robotic systems to which they are connected. We have been using a stereotaxic robot since 1989 and a microscope robot since 1995 in various surgical routine procedures. The future of these applications rely mainly on the technical progress in informatics, about image recognition to adapt the pre-planning to the actual surgical situation, to correct brain shifts (for instance), about image fusion, integrated knowledge such as brain atlases, as well as virtual reality. The future developments, covering surgical procedure, research and teaching, are sure to be far beyond our wildest expectations.

Forecasting↗
PubMed1997

Awareness of sexually transmitted disease among women and service providers in rural Bangladesh.

Sexually transmitted disease (STD) in rural Bangladesh is currently a topic of great concern. To date, little information is available in the literature regarding its prevalence. It is now known, however, that the current level of STD awareness among the rural population with regard to modes of transmission and means of prevention is inadequate. In 1994, the MCH-FP Extension Project (Rural) of ICDDR, B surveyed 8674 married women of reproductive age (MWRA) in 4 rural thanas to examine their awareness of STDs. The association between socio-demographic and programmatic factors (variables which affect STD information availability) and awareness of STDs was examined by both bivariate and multivariate analyses. Seven focus group discussions were conducted among groups of government health and family planning workers and paramedics to assess their knowledge of STDs and attitudes about their prevention. Only 12% of the original group had even a basic understanding about STDs and how to protect themselves from them. Twenty-five per cent of the women surveyed had ever heard of either syphilis or gonorrhoea. Of these women, less than half could mention specific mechanisms involved in the transmission of these diseases. Seven per cent reported that syphilis and gonorrhoea are transmitted through sexual intercourse. Thirteen per cent reported that the infections are transmitted from spouses to their partners. Four per cent reported that STDs can be spread by having multiple sexual partners. The results of logistic regression analysis indicate that awareness of STDs was higher among relatively older women than among younger women. Awareness of STDs was most strongly and positively associated with the education of both the women and their husbands. Awareness of STDs was also found to be higher among women who were more socially mobile (e.g. those who frequent cinemas or mothers' clubs). The findings of focus group discussions indicate that family planning and health care service providers have a moderate level of STD awareness. Modes of transmission and means of prevention, however, were areas of weakness. It will, therefore, be necessary, whether to prevent a potential STD epidemic or to combat current STD prevalence, to implement culturally acceptable and affordable means of disseminating knowledge in rural areas of Bangladesh. Training of health care providers will be an essential first step.

Adult↗
PubMed1997

[The robotization of neurosurgery: state of the art and future outlook].

Neurosurgery is by excellence a field of application for robots, based on multimodal image guidance. Specific motorized tools have been already developed and routinely applied in stereotaxy to position a probe holder or in conventional neurosurgery to hold a microscope oriented towards a given target. The potentialities of these approaches have triggered industrial developments currently commercially available. These systems use data bases, primarily coming from multimodal numerical images from X-ray radiology to magnetic resonance imaging. These spatially encoded data are transferred through digital networks to workstations where images can be processed and surgical procedures are preplanned, then transferred to the robotic systems to which they are connected. We have been using a stereotactic robot since 1989 and a microscope robot since 1995 in various surgical routine procedures. The future of these applications mainly rely on the technical progress in informatics, about image recognition to adapt the preplanning to the actual surgical situation, to correct brain shifts for instance, about image fusion, integrated knowledge such such as brain atlases, as well as virtual reality. The future developments, covering surgical procedure, research and teaching, will sure be far beyond our wildest expectations.

Forecasting↗
PubMed1996

Reverse transcriptase genotype and antiretroviral susceptibility of human immunodeficiency virus isolates from patients with advanced disease treated with didanosine: correlation with virologic response and survival.

To identify correlates of virologic response and survival, the reverse transcriptase (RT) genotype and in vitro antiviral susceptibility of human immunodeficiency virus (HIV) isolates from 20 patients treated with didanosine were studied. Patients had advanced HIV disease and were intolerant to or had failed zidovudine. Neither RT genotype nor antiviral susceptibility testing, as determined by a peripheral blood mononuclear cell-based assay, correlated with a virologic response to didanosine, as determined previously by quantitative serum culture. Only one (8%) of 12 isolates obtained after 6-12 months of treatment showed mutation at codon 74 conferring didanosine resistance. Reversions were seen in three of five patients with pre-treatment zidovudine resistance mutations at codons 70, but in none of eight with mutations at codon 215. Pretreatment isolates encoding mutations at RT codon 215 or encoding codon 123 asp were associated with both significantly greater CD4 lymphocyte depletion and shorter survival. In this cohort of patients with advanced HIV disease, neither rapid emergence of didanosine resistance nor rapid reversion of zidovudine resistance was observed. To better understand the relationship between virologic response and in vitro susceptibility to didanosine, more precise tools may be needed.

Anti-HIV Agents↗
PubMed1994

Molecular-weight factors affecting formation of the OBDD morphology in block copolymer blends.

Block copolymers undergo self-organization when the blocks are sufficiently incompatible, and generate a variety of periodic morphologies in the limit of strong segregation. An equilibrium morphology only recently added to the diblock copolymer phase diagram is the ordered bicontinuous double-diamond (OBDD) morphology, which possess a Pn3m space group. It has been observed over a very narrow composition range (ca. 4 vol%), thereby making it difficult to obtain in pure copolymers. This obstacle can, however, be surmounted by blending a copolymer with one of the parent homopolymers. In the present study, several symmetric poly(styrene-b-isoprene) diblock copolymers varying in molecular weight (M) have been blended with homopolystyrene to produce the OBDD morphology. Transmission electron microscopy is employed here to identify the morphologies in cryosections of each blend and reveals that, at intermediate molecular weights, the OBDD morphology is indeed observed. At low M, near the order-disorder transition, however, a lamellar catenoid or disordered morphology is preferred. At the other extreme, high-M blends are frustrated by molecular entanglements and adopt a cylindrical morphology.

Butadienes↗
PubMed1993

Effect of didanosine on human immunodeficiency virus viremia and antigenemia in patients with advanced disease: correlation with clinical response.

To determine if suppression of human immunodeficiency virus (HIV) replication during antiretroviral therapy correlates with clinical outcome, serial quantitative serum cultures and HIV p24 antigen measurements were made in patients with advanced HIV disease treated with didanosine. Twenty-one (78%) of 27 had viremia detected, and in 14 (67%) viral titer decreased by fivefold or more. Compared with those with no decrease, patients who had a decrease in titer were more likely to achieve a > or = 5% increase in body weight (8/12 vs. 0/7, P = .013) and had a significantly greater mean increase in body weight during treatment months 1-5. Occurrence of new AIDS-defining illnesses and survival were not significantly different between groups. Changes in p24 antigenemia did not correlate with any parameter of clinical outcome examined. Changing serum HIV titer is a marker of the virologic effect of didanosine therapy that correlates with the early clinical benefit as reflected by weight gain. However, correlation of this marker with long-term clinical benefit is uncertain.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Practical aspects of percutaneous transluminal angioplasty of the carotid artery.

The authors are reporting a total of 41 patients undergoing percutaneous transluminal angioplasty (PTA) at different levels of the carotid artery. The procedure for proximal carotid artery was performed on 17 patients, for mid or distal common carotid artery on 4 patients, for carotid bifurcations on 5 patients, for internal carotid artery on 6 patients, for external carotid artery on 4 patients, and for fibromuscular dysplasia of the internal carotid artery on 5 patients. We also collected research on an additional 53 patients from the literature for a total of 94 patients. To date, we have not encountered any mortalities nor neurologic complications in performing this procedure. Thus, we believe that PTA may be performed with reasonable safety and as an alternate procedure in the treatment of carotid artery stenosis.

Adult↗
PubMed1982

Health, disease and health-care in rural Bangladesh.

During two periods of almost 3 months each, a study was done in three villages of Tangail District in Bangladesh. One of the objectives was to find out how the fields of traditional medicine (Ayurveda and Unani), folk medicine and allopathic medicine were related to each other, and which processes could be discerned in these interrelationships. In this respect an important outcome was that traditional medicine had almost disappeared in this area and that Western medicine holds a very strong position. Another objective was to study the illness-behaviour of various economic categories of villagers. Here we found that the poor made much more use of the government facilities than the rich. In fact, these facilities have a large potential, but there are many defects in the way they are operating, so that the potential is not realized at all. We also studied the cures which the practitioners of folk medicine and those of Western medicine are offering to their clients. One of the conclusions was that the practices of the unqualified allopathic practitioners, who hold a strong position in the countryside, are often a hazard to health.

Bangladesh↗