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Biomedical subjects

J Bell

Publications and source records attributed to J Bell.

At least 91 records · Page 5Linked to original sources
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↗
PubMed1999

Cancer of mouth, pharynx and nasopharynx in Asian and Chinese immigrants resident in Thames regions.

Studies on migrants can generate important clues on the etiology of cancer. The purpose of the present study was to determine the relationship between ethnic origin and the incidence of oral and pharyngeal cancers among residents of the Thames regions in southern England. Records from the Thames Cancer Registry during the period 1986-91 were examined and south Asians and Chinese ethnic immigrants flagged using their place of birth and names. Computation of relative incidence among head and neck cancers (n = 7222) showed that oral cancer was significantly higher among Asians (95/232 = 40.9%) and nasopharyngeal cancer among Chinese (45/67 = 67.2%). Some differences in the intra-oral site of cancer and ethnic origin were noted. The ethnic migrants were significantly younger (Asians 51.6 +/- 34.8 years, Chinese 47.6 +/- 14.8 years) compared to the rest of the population (64.8 +/- 15.6 years) at the time of cancer diagnosis (p = 0.0) but no significant differences were found for the stage of presentation. The mean survival period for a cancer of the head and neck was 2.2 years and significant differences in cumulative rates of survival were noted among the three groups studied (p = 0.003). A strong correlation was noted between the incidence of oral cancer and local authorities with a high percentage of Asian residents. The south Asian and Chinese ethnic minorities constitute important high risk groups for oral and nasopharyngeal cancer, for whom targeted prevention is indicated.

Adult↗
PubMed1999

Evidence based general practice.

OBJECTIVES: To estimate the proportion of interventions in general practice that are based on evidence. DESIGN: A one-year cross-sectional study involving all consultations by patients over age 15 years seen in 34 national primary health care centers. SETTING: The rural Castellon provincial district within the Valencian Community in eastern Spain, with a total population of 21,155 inhabitants. SUBJECTS: of 1990 case histories registered in the course of one year, 4800 consultations were identified; of these, 2341 (49%) distinct diagnosis-intervention pairs were identified and coded. MAIN RESULTS: The evidence basis for the diagnosis-intervention pairs in the study was derived from a computerized search of the scientific literature published in 1992-1996. The quality of the evidence was classified according to the method of Ellis et al. Within the 2341 diagnosis-intervention pairs, there was positive evidence in support of the intervention used in 55%. The evidence basis was sound for 42%, with 38% being based on Type I (clinical trials) evidence and 4% on Type II evidence. The most frequently presenting diseases involved the circulatory (18.7%), respiratory (14.9%), nervous (14.2%), musculo-skeletal (12.5%) and nutrition and metabolism and digestive systems, with 12.1% each. CONCLUSIONS: Clinical practice was clearly supported by positive evidence of all Types (I-III) in a total of 55% of interventions, and by good positive evidence of Type I or II in 42% of interventions. The percentage of evidence-based interventions in general practice serving a substantial population in rural Spain was lower than had been reported by some authors.

Cross-Sectional Studies↗
PubMed1999

On the relationships of high-frequency hearing loss and cochlear pathology to the acoustic startle response (ASR) and prepulse inhibition of the ASR in the BXD recombinant inbred series.

The measurement of the acoustic startle response (ASR) and prepulse inhibition (PPI) of the ASR in many inbred strains of mice, including C57BL/6 and DBA/2, may be complicated by age-related high-frequency hearing loss (HFHL) and the associated cochlear pathology. Willott and Erway (1998) have recently reported on the age-related changes of the acoustic brain response in the BXD recombinant inbred (RI) series. Based on these data, the RI series was divided into three groups: juvenile-, intermediate-, and adult-onset HFHL. Each of these groups was tested using paradigms which varied the frequency or intensity of the auditory startle and prepulse stimuli. The results obtained in adolescent mice (6-8 weeks) demonstrate that ASR performance is independent of HFHL; there was no group-dependent decline in the ASR amplitudes for high-frequency stimuli. The expected effect of HFHL on PPI is to increase the salience of the still-audible tones. In response to a white-noise prepulse stimulus, the PPI in the juvenile-onset group (which shows marked HFHL at 6 weeks) was similar to that in the adult-onset group. However, when the prepulse stimulus was a pure tone, the juvenile group showed a decrease in salience across all frequencies tested (5-20 kHz). The data point out the need for carefully constructing auditory tasks in the BXD RI series, to avoid the confounding effects of HFHL.

Acoustic Stimulation↗
PubMed1999

The type of somatic mutation at APC in familial adenomatous polyposis is determined by the site of the germline mutation: a new facet to Knudson's 'two-hit' hypothesis.

APC is often cited as a prime example of a tumor suppressor gene. Truncating germline and somatic mutations (or, infrequently, allelic loss) occur in tumors in FAP (familial adenomatous polyposis). Most sporadic colorectal cancers also have two APC mutations. Clues from attenuated polyposis, missense germline variants with mild disease and the somatic mutation cluster region (codons 1,250-1,450) indicate, however, that APC mutations might not result in simple loss of protein function. We have found that FAP patients with germline APC mutations within a small region (codons 1,194-1,392 at most) mainly show allelic loss in their colorectal adenomas, in contrast to other FAP patients, whose 'second hits' tend to occur by truncating mutations in the mutation cluster region. Our results indicate that different APC mutations provide cells with different selective advantages, with mutations close to codon 1,300 providing the greatest advantage. Allelic loss is selected strongly in cells with one mutation near codon 1,300. A different germline-somatic APC mutation association exists in FAP desmoids. APC is not, therefore, a classical tumor suppressor. Our findings also indicate a new mechanism for disease severity: if a broader spectrum of mutations is selected in tumors, the somatic mutation rate is effectively higher and more tumors grow.

Adenoma↗
PubMed1999

Second malignant neoplasms after a first cancer in childhood: temporal pattern of risk according to type of treatment.

The variation in the risk of solid second malignant neoplasms (SMN) with time since first cancer during childhood has been previously reported. However, no study has been performed that controls for the distribution of radiation dose and the aggressiveness of past chemotherapy, which could be responsible for the observed temporal variation of the risk. The purpose of this study was to investigate the influence of the treatment on the long-term pattern of the incidence of solid SMN after a first cancer in childhood. We studied a cohort of 4400 patients from eight centres in France and the UK. Patients had to be alive 3 years or more after a first cancer treated before the age of 17 years and before the end of 1985. For each patient in the cohort, the complete clinical, chemotherapy and radiotherapy history was recorded. For each patient who had received external radiotherapy, the dose of radiation received by 151 sites of the body were estimated. After a mean follow-up of 15 years, 113 children developed a solid SMN, compared to 12.3 expected from general population rates. A similar distribution pattern was observed among the 1045 patients treated with radiotherapy alone and the 2064 patients treated with radiotherapy plus chemotherapy; the relative risk, but not the excess absolute risk, of solid SMN decreased with time after first treatment; the excess absolute risk increased during a period of at least 30 years after the first cancer. This pattern remained after controlling for chemotherapy and for the average dose of radiation to the major sites of SMN. It also remained when excluding patients with a first cancer type or an associated syndrome known to predispose to SMN. When compared with radiotherapy alone, the addition of chemotherapy increases the risk of solid SMN after a first cancer in childhood, but does not significantly modify the variation of this risk during the time after the first cancer.

Age of Onset↗
PubMed1999

Tumor metastasis biopsy as a surrogate marker of response to melanoma immunotherapy.

In patients undergoing immunotherapy for metastatic melanoma, the clinical response in immunotherapeutic trials may be partial or difficult to detect. Tumor metastasis biopsy allows direct characterisation of an anti-tumor immunological response. During a phase I/II trial of granulocyte macrophage colony stimulating factor (GM-CSF) transduced autologous melanoma immunotherapy, the cellular response was examined by immunohistochemical analysis in a limited number of tumor biopsies taken from patients who either responded or progressed. Clinical response was associated with tumor infiltration by CD4+ and CD8+ T-cells, macrophages and differentiated dendritic cells (DC), and expression of HLA-DR by the tumor cells. This tumor infiltration was associated with increased melanoma-specific peripheral blood precursor cytotoxic T-lymphocyte (pCTL) and the ability to obtain tumor-infiltrating lymphocytes in vitro. In contrast, progression or a lack of clinical response was associated with a lack of T-cell and DC infiltration into the tumor tissue in all such biopsies. Macrophages and eosinophils infiltrated these tumors, while T-cells and DC were present at some distance from the tumor. These preliminary data strongly suggest that the location and extent of T-cell and DC infiltration, as well as the expression of HLA-DR by tumor cells are associated with a clinical response in this form of melanoma immunotherapy.

Adult↗
PubMed1999

A matched case-control study of convenience store robbery risk factors.

Convenience store clerks have been shown to be at high risk for assault and homicide, mostly owing to robbery or robbery attempts. Although the literature consistently indicates that at least some environmental designs are effective deterrents of robbery, the significance of individual interventions and policies has differed across past studies. To address these issues, a matched case-control study of 400 convenience store robberies in three metropolitan areas of Virginia was conducted. Conditional logistic regression was implemented to evaluate the significance of various environmental designs and other factors possibly related to convenience store robbery. Findings indicate that numerous characteristics of the surrounding environment and population were significantly associated with convenience store robbery. Results also showed that, on a univariate level, most crime prevention factors were significantly associated with a lower risk for robbery. Using a forward selection process, a multivariate model, which included cash handling policy, bullet-resistant shielding, and numerous characteristics of the surrounding area and population, was identified. This study addressed numerous limitations of the previous literature by prospectively collecting extensive data on a large sample of diverse convenience stores and directly addressing the current theory on the robbers' selection of a target store through a matched case-control design.

Analysis of Variance↗
PubMed1999

Suggestive linkage of the parathyroid receptor type 1 to osteoporosis.

We have investigated the role of 23 candidate genes in the control of bone mineral density (BMD) by linkage studies in families of probands with osteoporosis (lumbar spine [LS] or femoral neck [FN] BMD T score < -2.5) and low BMD relative to an age- and gender-matched cohort (Z score < -2.0). One hundred and fifteen probands (35 male, 80 female) and 499 of their first- or second-degree relatives (223 males and 276 females) were recruited for the study. BMD was measured at the LS and FN using dual-energy X-ray absorptiometry and expressed as age- and gender-matched Z scores corrected for body mass index. The candidate genes studied were the androgen receptor, type I collagen A1 (COLIA1), COLIA2, COLIIA1, vitamin D receptor (VDR), colony-stimulating factor 1, calcium-sensing receptor, epidermal growth factor (EGF), estrogen receptor 1 (ESR1), fibrillin type 1, insulin-like growth factor 1, interleukin-1 alpha (IL-1alpha), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-11 (IL-11), osteopontin, parathyroid hormone (PTH), PTH-related peptide, PTH receptor type 1 (PTHR1), transforming growth factor-beta 1, and tumor necrosis factors alpha and beta. Sixty-four microsatellites lying close to or within these genes were investigated for linkage with BMD. Using the program MapMaker/Sibs there was suggestive evidence of linkage between BMD and PTHR1 (maximum LOD score obtained [MLS] 2.7-3.5). Moderate evidence of linkage was also observed with EGF (MLS 1.8), COLIA1 (MLS 1.7), COLIIA1/VDR (MLS 1.7), ESR1 (MLS 1.4), IL-1alpha (MLS 1.4), IL-4 (MLS 1.2), and IL-6 (MLS 1.2). Variance components analysis using the program ACT, correcting for proband-wise ascertainment, also showed evidence of linkage (p </= 0.05) at markers close to or within the candidate genes IL-1alpha, PTHR1, IL-6, and COLIIA1/VDR. Further studies will be required to confirm these findings, to refine the location of gene responsible for the observed linkage, and to screen the candidate genes targeted at these loci for mutations.

Adolescent↗