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Biomedical subjects

J Bell

Publications and source records attributed to J Bell.

At least 73 records · Page 4Linked to original sources
PubMed2000

Cancer registries--future development and uses in Britain.

Cancer registries are a vital source of information on cancer epidemiology and cancer services. Their role has changed dramatically over the past 15 years. A number of factors will affect their future role, including health service changes, information technology, development of clinical datasets and greater demand for both health service and public information. The potential of cancer registration needs to be realized by clinicians and health authorities: how they can use the data, its limitations, and how they can support and influence it through this period of change. A strategic direction is needed so that cancer registries develop into a dynamic, interactive source of knowledge for the twenty-first century.

Confidentiality↗
PubMed2000

Mycosis fungoides: review of epidemiological observations.

BACKGROUND: Mycosis fungoides (MF) is a chronic cutaneous T-cell lymphoma characterized by small cells with cerebriform nuclei that usually express a mature peripheral T-helper cell (CD4+) immunophenotype. Its evolution is typically quite slow, with years between the first manifestations and development of advanced stages of disease. OBJECTIVE: The purpose of the present paper is to contribute to the material about MF already present in the literature. The review articles that have appeared to date fundamentally address the morphological characteristics, diagnostic criteria and treatment of the disease; in contrast, the present study centers on the evolution of the incidence of MF and on the knowledge of the possible risk factors implicated in its development. METHODS: Review of published papers about MF epidemiology. RESULTS: The evidence suggests that the incidence is increasing, but this may be artifactual due to improved diagnostic techniques. The risk of MF is limited to gender and race, being higher in males and in blacks. Survival is highly stage dependent, but 90% of patients survive 15 years with only 10% of cutaneous involvement. Few risk factors have been identified, but several studies have found an association with industrial exposure, particularly to oils. CONCLUSION: MF is a rare disease and its risk factors have not been studied in any great detail. A European case-control study in progress will substantially increase the evidence available and progress towards identifying a prevention strategy.

Adult↗
PubMed2000

Neurotoxicity and dysfunction of dopaminergic systems associated with AIDS dementia.

Infection with the human immunodeficiency virus (HIV) selectively targets the basal ganglia resulting in loss of dopaminergic neurons. Although frequently asymptomatic, some patients may develop signs of dopamine deficiency de novo. Accordingly, they are highly susceptible to drugs that act on dopaminergic systems. Both neuroleptics and psychostimulants may exacerbate these symptoms. Experimental evidence suggests that viral proteins such as gp120 and Tat can cause toxicity to dopaminergic neurons, and this toxicity is synergistic with compounds such as methamphetamine and cocaine that also act on the dopaminergic system. In addition, other neurotransmitters that modulate dopaminergic function, such as glutamate and opioids, may also modify the susceptibility of the dopamine system to HIV. Therefore, a thorough understanding of the mechanisms that lead to this selective neurotoxicity of dopaminergic neurons would also likely lead to the development of therapeutic modalities for patients with HIV dementia.

AIDS Dementia Complex↗
PubMed2000

Influence of gelatin and bovine serum lubricants on ultra-high molecular weight polyethylene wear debris generated in in vitro simulations.

Ultra-high molecular weight polyethylene (UHMWPE) wear debris induced osteolysis has a major role in the late aseptic loosening and ultimate failure of total hip replacements (THR). Clinically relevant in vitro simulations of wear are essential to predict the osteolytic potential of bearing surfaces in artificial hip joints. Newborn calf or bovine serum has been accepted as a boundary lubricant for such in vitro tests, but its biological stability has been questioned. This study compared the wear factors, number of wear particles and levels of microbial contamination produced in bovine serum and a gelatin-based lubricant. The wear factors produced by the two lubricants were not significantly different, however the wear debris morphology produced was substantially different. The bovine serum became contaminated with micro-organisms within 28 h, whereas the protein-based lubricant remained uncontaminated. The results showed that bovine serum was not a stable boundary lubricant. They also showed that although the wear factors for the two solutions were not significantly different, the protein-based lubricant was not a suitable alternative to bovine serum because the wear debris produced was not clinically relevant.

Animals↗
PubMed2000

A risk-benefit analysis of methadone maintenance treatment.

Methadone maintenance treatment for heroin (diamorphine) addiction has been extensively researched. There is consistent evidence that while in treatment, heroin addicts are at a lower risk of death, are less involved in crime, and feel and function better than while using heroin. Despite the research evidence supporting methadone treatment, there remains widespread public scepticism about this form of treatment. This scepticism is frequently expressed in terms of the perceived risks of methadone treatment. The perceived risk that methadone treatment may maintain people in an addicted lifestyle is not supported by research literature. The risks of treatment include an increased risk of death during induction into treatment, and risks of diversion of drugs to the black market. For some patients, adverse effects of methadone pose a problem and the availability of new pharmacotherapies may provide useful options for these patients. Risks can be reduced and benefits increased by directing greater attention to the quality of treatment.

Analgesics, Opioid↗
PubMed2000

NFkappaB activation, TNF-alpha expression, and apoptosis in the AIDS-Dementia-Complex.

The role of NFkappaB activation and its relationship to inflammatory mediators and apoptosis in the HIV-infected brain have remained uncertain. The cellular and regional distribution of NFkappaB, TNF-alpha, and apoptosis was examined in the frontal cortex (FC), deep white matter (DWM) and the basal ganglia (BG) of 17 patients with ADC. Nuclear staining for NFkappaB was localized predominantly to perivascular microglia/macrophages in the BG and DWM and correlated with ADC severity. Correlations were further found with HLA-DR, iNOS, TNF-alpha, and gp41 expression in these regions. The number of TUNEL-positive cells, particularly in the BG, correlated with ADC stage. Logistic regression analysis further showed a significant relationship between the likelihood of TUNEL staining in the BG and worsening cognitive impairment.

AIDS Dementia Complex↗
PubMed2000

Melanoma and additional primary cancers.

The aim of this study was to examine the occurrence of additional, unrelated primary cancers in patients with melanoma. Data from the hospital-based, melanoma registry of a specialist unit (the Melanoma Unit at Charing Cross Hospital, London, UK) were compared with the incidence rates in a population-based cancer registry (the Thames Cancer Registry). In total, 2076 patients with the histological diagnosis of melanoma established between 1960 and 1997 who were registered with the Melanoma Unit at Charing Cross Hospital, were included in the study. Patterns in time and in the tumour type of the additional cancers were analysed in the cohort. The relative risk of subsequent cancers was evaluated, the number of expected cancers being calculated by applying incidence rates in the population of south-east England to the person-years of follow-up in the cohort. Sixty-six (3%) of the 2076 evaluable patients had a history of, or developed, 69 histologically verified additional cancers, the commonest being colorectal, breast and lymphoma. Twenty-six additional cancers preceded the diagnosis of melanoma by 1-42 years, 16 were diagnosed within 12 months and 27 followed the diagnosis of melanoma, 1-28 years later. Seven cancers occurred after chemotherapy for metastatic melanoma: two colorectal, one bladder, one renal, two myelodysplasias and one acute myeloid leukaemia. The relative risk of additional cancers developing after the diagnosis of melanoma during the 8537 evaluable years-at-risk was 0.64 (95% confidence interval 0.41-0.96; P = 0.0006). Thus, the risk of additional cancers following treatment for metastatic melanoma in this cohort is small. The potential influence of other factors on the occurrence of additional cancers observed overall in this study requires further investigation.

Adolescent↗
PubMed2000

Infection control.

Explore the source record for details and available documents.

Creutzfeldt-Jakob Syndrome↗
PubMed1999

Isolation of beta-lactamase positive vancomycin resistant Enterococcus faecalis; first case in Australia.

An increasing number of clinical isolates of vancomycin resistant enterococci (VRE) have been reported in the literature since 1988. Only a few cases of beta-lactamase producing VRE have been described worldwide. This article reports the first case of beta-lactamase positive VRE in Australia. This strain of Enterococcus faecalis was isolated from a patient with non-Hodgkin's lymphoma who subsequently underwent a bone marrow transplant. Screening of all ward contacts did not detect any further case of beta-lactamase producing VRE. With the development of multiple antibiotic resistance in enterococci, additional infection surveillance protocols have been implemented in the hospital. These include routine screening of 'at risk' patients, instigating relevant infection control measures for management of VRE positive patients and controlling the usage of vancomycin in order to limit the development of resistant isolates.

Adult↗
PubMed1999

Angiotensin-converting-enzyme gene insertion/deletion polymorphism and response to physical training.

BACKGROUND: The function of local renin-angiotensin systems in skeletal muscle and adipose tissue remains largely unknown. A polymorphism of the human angiotensin converting enzyme (ACE) gene has been identified in which the insertion (I) rather than deletion (D) allele is associated with lower ACE activity in body tissues and increased response to some aspects of physical training. We studied the association between the ACE gene insertion or deletion polymorphism and changes in body composition related to an intensive exercise programme, to investigate the metabolic effects of local human renin-angiotensin systems. METHODS: We used three independent methods (bioimpedance, multiple skinfold-thickness assessment of whole-body composition, magnetic resonance imaging of the mid-thigh) to study changes in body composition in young male army recruits over 10 weeks of intensive physical training. FINDINGS: Participants with the II genotype had a greater anabolic response than those with one or more D alleles for fat mass (0.55 vs -0.20 kg, p=0.04 by bioimpedance) and non-fat mass (1.31 vs -0.15 kg, p=0.01 by bioimpedance). Changes in body morphology with training measured by the other methods were also dependent on genotype. INTERPRETATION: II genotype, as a marker of low ACE activity in body tissues, may conserve a positive energy balance during rigorous training, which suggests enhanced metabolic efficiency. This finding may explain some of the survival and functional benefits of therapy with ACE inhibitors.

Adipose Tissue↗
PubMed1999

Analysis of a model of membrane potential for a skin receptor.

A linear model for the membrane potential of a nerve ending associated with a sense-of-touch skin receptor is formulated and analyzed. Because the nerve has cytoplasmic extensions and is stimulated through a membrane strain mechanism, the model is a generalized cable equation with linear oblique boundary conditions (i.e. boundary conditions involving both time and space derivatives). The model is stimulated through a certain conductance parameter. We establish solutions for the problem and we consider a particular physiological question, both analytically and computationally, of determining conditions on parameters and stimulus which give threshold level potential values at a particular boundary point.

Linear Models↗
PubMed1999

Pseudo-Fleischer ring after hyperopic laser in situ keratomileusis.

A 37-year-old woman had bilateral hyperopic laser in situ keratomileusis (LASIK). Six months postoperatively, an epithelial pigmentation ring pattern was identified on both corneas. The appearance of the ring pattern was similar to the iron deposits of the Fleischer ring of keratoconus. While corneal iron deposits in various patterns have been reported after other forms of ocular therapeutic and refractive surgery, this is the first report of the association between hyperopic LASIK and a corneal iron line, which we have called the "pseudo-Fleischer ring."

Adult↗
PubMed1999

Complications of phacoemulsification on the first postoperative day: can follow-up be safely changed?

PURPOSE: To establish the rate of complications detected on the first postoperative day and therefore the need for evaluation on that day. SETTING: Hinchingbrooke Hospital, Huntingdon, England. METHODS: Complications detected on the first day after phacoemulsification cataract surgery were retrospectively reviewed over 8 months. Ophthalmic nurse practitioners performed the 1 day postoperative examination and kept a log of patients seen, recording complications detected and whether referral to a physician was required. All patients had had routine phacoemulsification with intraocular lens implantation without anterior vitrectomy or trabeculectomy, as identified from the log book and cross-checked with operating theater records. Notes were reviewed if a complication or referral was recorded. Most cases were performed under local anesthesia as day cases using a temporal corneal approach. Sections were routinely left unsutured unless enlarged or closure was not satisfactory at the conclusion of surgery. RESULTS: The review yielded 392 patients. Six (1.53%) had intraocular pressure (> or = 30 mm Hg) requiring treatment, 1 (0.26%) had painless iris prolapse, 11 (2.81%) had corneal abrasions, and 7 (1.78%) were given a more intensive steroid regime. No cases of fibrinous uveitis were recorded. CONCLUSIONS: Potentially sight-threatening complications present on the first postoperative day, albeit infrequently. With our current practice and case mix, the need for this review persists. It is possible to reduce the demand on physician time by using appropriately trained nonmedical practitioners.

Adult↗