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Biomedical subjects

A Fraser

Publications and source records attributed to A Fraser.

At least 91 records · Page 5Linked to original sources
PubMed1996

The role of an open-access bleeding unit in the management of colonic haemorrhage. A 2-year prospective study.

BACKGROUND: Major colonic haemorrhage poses difficult diagnostic and therapeutic problems and, in contrast to upper gastrointestinal bleeding, has no generally accepted plan of management. METHODS: We report community-based prospective data accumulated over 2 years (1991-93) on 1602 patients referred to an open-access bleeding unit with suspected gastrointestinal haemorrhage. RESULTS: Of 278 (17%) admissions with suspected lower GI haemorrhage, 252 were confirmed. Forty-eight per cent were defined as "significant' bleeds, with a decrease in haemoglobin and cardiovascular compromise. Of 102 significant bleeds in subjects more than 60 years old, 29% rebled, and 12.6% required emergency surgery. Diverticular disease (24%) was the commonest diagnosis, with tumours, infective colitis, and inflammatory colitis each at 10%. The overall 30-day mortality for colonic bleeding was 5.1% (13 of 252), with only 1 death occurring in the group less than 60 years old. CONCLUSIONS: This study provides a unique database for the natural history of colonic bleeding and its management within the setting of a specialized bleeding unit.

Adult↗
PubMed1995

Serological reactivity against cyst and tachyzoite antigens of Toxoplasma gondii determined by FAST-ELISA.

AIMS: To obtain quantitative data on the human serological response to Toxoplasma gondii tachyzoite and bradyzoite antigens. METHODS: Serum samples from 30 patients who had positive antibody titres against T gondii and from 14 who were seronegative, together with sequential serum samples from four infected individuals, were screened by FAST-ELISA. RESULTS: Serum samples from the 30 seropositive patients showed high IgG and IgM titres against the T gondii tachyzoite antigen but very low responses to cyst antigen. This result was borne out in sequential serum samples from patients with toxoplasmosis. CONCLUSION: Antibody recognition of the cystic stage of T gondii is low, implying that either this stage is poorly immunogenic or that the antigen load is low.

Animals↗
PubMed1995

A critique of 'at risk' pressure sore assessment tools.

This paper critiques pressure sore risk assessment tools. No attempt is made to describe individual tools in detail as this literature is available elsewhere. The economic case for risk assessment is presented along with the criteria for an effective risk assessment instrument. Reliability and validity studies are reviewed in relation to three risk assessment tools: Norton, Waterlow and Braden. Finally a number of issues related to threshold scores, research design and the need to view pressure sores as a clinical problem rather than a nursing problem are discussed.

Humans↗
PubMed1994

Asymmetrical orientation to edges of an openfield: modulation by striatal dopamine and relationship to motor asymmetries in the rat.

Rats with unilateral 6-hydroxydopamine (6-OHDA, 4 or 8 micrograms) or sham lesions of the substantia nigra were examined (undrugged) for asymmetrical orientation to edges of a large openfield. Lesioned rats preferentially aligned with the edge such that the intact striatum was contralateral to the edge. The magnitude of this asymmetry was greatest in rats lesioned with the highest dose of 6-OHDA. There was no population left/right hemispheric asymmetry in the extent to which unilateral striatal dopamine (DA) depletion produces this behavioral bias. In sham-lesioned rats, endogenous imbalances in striatal DA activity (DOPAC/DA) were related to the direction of edge orientation, such that the more active striatum tended to be contralateral to the edge. Also in shams, the direction of this orientational asymmetry was not significantly related to the direction of motor bias measured as amphetamine- and apomorphine-induced turning behavior in rotometers (having no edges). However, the magnitudes of sensorimotor (edge behavior) and motor (turning) asymmetries were negatively correlated. The results extend previous findings that asymmetrical edge behavior is a sensitive index of imbalances in striatal DA activity, not only in DA-depleted rats, but in intact rats as well. Furthermore, sensorimotor and motor asymmetries, while both under DAergic influence, are largely independent processes.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Comparison of PCR-based restriction length polymorphism analysis of urease genes with rRNA gene profiling for monitoring Helicobacter pylori infections in patients on triple therapy.

Multiple isolates of Helicobacter pylori from antral biopsies of nine patients were examined by DNA fingerprinting. Analysis of rRNA gene patterns and HaeIII restriction fragment length polymorphism of PCR-amplified urease genes were compared and used to study colonization before and after failed triple therapy. H. pylori isolates from a single biopsy shared the same HaeIII DNA fingerprint regardless of the isolation method (plate or broth). DNA pattern types of paired strains of H. pylori were distinct between patients and were not grossly affected by treatment except for one patient with an altered strain type. H. pylori infections were generally associated with several subpopulations of strains, evident from the subtypic variation before and after treatment, detectable by both DNA fingerprinting methods. The urease gene patterns also provided evidence that some cultures of H. pylori probably contained a mixture of genomic subtypes. The study suggests that triple therapy has the effect either of inducing minor genomic variations or of changing the proportions of different subtypes of H. pylori. It was concluded that urease gene profiling provides a simple yet reliable method of establishing whether treatment failures are attributable to incomplete eradication of H. pylori.

Anti-Bacterial Agents↗
PubMed1992

Parthenogenetic stem cells in postnatal mouse chimeras.

The ability of parthenogenetic (pg) cells to contribute to proliferating stem cell populations of postnatal aggregation chimeras was investigated. Using DNA in situ analysis, pg participation was observed in highly regenerative epithelia of various regions of the gastrointestinal tract, e.g., stomach, duodenum and colon, in the epithelia of tongue and uterus and in the epidermis. Pg cells also contributed to the epithelium of the urinary bladder, which is characterized by a relatively slow cellular turnover. Using a sensitive proliferation marker to determine division rate of pg and normal (wt) cells in tissues of a 24-day-old chimera, no significant differences between pg and fertilized cells were observed. However, in colon and uterus of a pg <==> wt chimera aged 101 days, a significant loss of proliferative capacity of pg cells was found. In the colon, this loss of proliferative potential was accompanied by an altered morphology of pg crypts. In general, they were situated at the periphery of the epithelium and lacked access to the lumen, with consequent cystic enlargement and flattened epithelium. No obvious morphological changes were observed in the pg-derived areas of the uterine epithelium of this chimera. Our results provide evidence that pg cells can persist as proliferating stem cells in various tissues of early postnatal chimeras. They suggest that pg-derived stem cells may cease to proliferate in restricted areas of the gastrointestinal tract and in the uterine epithelium of pg <==> wt chimeras of advanced age.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

The pharmacology of chewable versus regular carbamazepine in chronically treated children with epilepsy.

We report the first comparison of Chewable and Regular Carbamazepine (CBZ) tablets in children with epilepsy. Forty-four children receiving chronic monotherapy CBZ participated. In month 1 children received regular CBZ; in month 2, the same dose of Chewable CBZ. Once per week fasting predose CBZ and CBZ epoxide serum levels were determined. In a subset of 15 children, at the end of each month serum levels were obtained every 2 hours for 12 hours beginning pre-dose. Standards for CBZ and CBZ epoxide were tested in each centre. Overall, weekly levels showed no consistent differences between the month on chewable CBZ and regular CBZ. Seizure control and rates of reported side effects were similar. In five patients chewable CBZ produced higher peak CBZ levels while five had higher peaks with regular CBZ. In conclusion, regular and chewable CBZ often have unpredictable differences in peak but not trough levels of CBZ suggesting that peak level side effects with one form of CBZ might be alleviated by changing to the other.

Carbamazepine↗
PubMed1991

IT training. A classroom at your fingertips.

Computer-based training is still in its infancy in the NHS. Yet it could offer a cost-effective solution to the challenges posed by new technology, argues Andrew Fraser.

Computer User Training↗
PubMed1991

The effect of GR122311X, a bismuth compound with H2-antagonist activity, on 24-hour intragastric acidity.

GR122311X (ranitidine bismuth citrate Glaxo Group Research Ltd) is a bismuth compound with histamine H2-receptor antagonist activity. The gastric acid antisecretory activity of three oral dosage regimens of GR122311X was compared with placebo and 150 mg ranitidine b.d. The median 24-h integrated intragastric acidity was 38, 26 and 18% of the median placebo value during dosing with GR122311X 196, 391 and 782 mg b.d., respectively. The 24-h acid suppression with GR122311X 391 mg b.d. was not significantly different to that produced by 150 mg ranitidine b.d. (24% of placebo acidity). The median 24-h urinary bismuth excretion increased with rising dosage of GR122311X from 19.2 micrograms with 196 mg b.d., to 36.4 micrograms with 391 mg b.d., to 68.7 micrograms with 782 mg b.d. In conclusion, GR122311X is an effective antisecretory agent with modest systemic bismuth absorption.

Adolescent↗
PubMed1991

Peripheral nerve function in persons with asymptomatic or minimally symptomatic HIV disease: absence of zidovudine neurotoxicity.

Nucleoside-induced neuropathy characteristically appears as a painful, symmetric, distal polyneuropathy. To evaluate the neurotoxic potential of zidovudine (ZDV, or azidothymidine), in persons with little confounding human immunodeficiency virus (HIV) neuropathy, we evaluated peripheral nerve function in persons completing placebo-controlled studies of ZDV in early HIV disease. Participants had been receiving placebo or ZDV at doses of 800-1,200 mg daily for a median 52 weeks at the time of evaluation. Neuropathic symptoms and abnormalities of motor and sensory function were present in fewer than 10% of both treatment groups. Depressed reflexes were found in 19% of the ZDV group and 18% of the placebo group. Quantitative sensory testing for vibration was abnormal in fewer than 10% of participants and the absolute scores favored the ZDV group. We thus found a low prevalence of peripheral nerve abnormalities and no evidence of ZDV neurotoxicity in this population.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Office proctology and sigmoidoscopy.

Proctoscopy and sigmoidoscopy are readily acquired skills and should be routine office procedures for general practitioners. Correct positioning of the patient is of utmost importance to a successful examination.

Family Practice↗
PubMed1989

Changing trends in drug use: the second follow-up of a local heroin using community.

The first Seadown study documented the way in which police action in closing down the cohort's central point for meeting and drug distribution had effectively destroyed the long established heroin distribution network. Throughout the period of low heroin availability the social network of the cohort was preserved as members developed a whole range of alternative coping styles (displacement activities) in compensation for the enforced abstinence caused by the heroin drought. During the period of observation heroin returned to Seadown initially through a small, unstable and informal distribution co-operative and stayed in this phase until a new central meeting place had been established. Thereafter once a pyramidal distribution network developed, most cohort members were able to modify or stop their displacement activities to accommodate the re-availability of heroin.

Cohort Studies↗