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Biomedical subjects

A Fraser

Publications and source records attributed to A Fraser.

At least 19 recordsLinked to original sources
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

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↗
PubMed1989

Measurement of blood pressure.

Blood pressure estimation is probably the most frequent and least accurate clinical measurement carried out by both nursing staff and doctors. The more the observer realizes that this routine and apparently simple procedure needs skill, strict observance of rules, and a clear understanding of the mechanics involved so will his or her readings be valid.

Blood Pressure Determination↗
PubMed1989

Diagnosis of leukocyte disorders with an automated haematology counter (Technicon H-1 analyser).

The differential leukocyte count is very important in the diagnosis of various leukocyte disorders. Newer automated haematology counters can now perform differential leukocyte count, thus reducing the dependence on experienced medical technologists. The Technicon H.1 analyser (Technicon Instruments Corp., New York, USA) can perform even more complicated tasks like flagging abnormal cells, generating cytograms based on cell size and cytochemistry. In this paper we report on the useful cellular characteristics of the various leukocyte disorders as measured by the Technicon H.1 analyser.

Evaluation Studies as Topic↗
PubMed1988

Pulsed Doppler evaluation of regurgitation in mitral valve prostheses.

Prosthetic mitral valve regurgitation was evaluated by both pulsed Doppler ultrasound and left ventriculography. Pulsed Doppler ultrasound was found to have only a 20% sensitivity in detecting prosthetic mitral valve regurgitation documented by left ventriculography. Possible reasons for this poor sensitivity include 1) an eccentric jet not identified by the small pulsed Doppler sample volume; 2) prosthesis interference with the Doppler signal in the apical four chamber view; and 3) the large angle of incidence between the pulsed Doppler signal and the regurgitant jet. Mitral insufficiency, especially when not severe, may be missed by this technique. Care must be taken in interpreting negative results from a pulsed Doppler ultrasound evaluation of a prosthetic mitral valve.

Echocardiography↗
PubMed1988

Massive carbamazepine overdose: clinical and pharmacologic observations in five episodes.

We report five episodes of carbamazepine (CBZ) intoxication in four patients. Clinically, there were four distinct stages: I--coma, seizures (CBZ levels more than 25 micrograms/ml [105 mumol/l]); II--combativeness, hallucinations, choreiform movements (15 to 25 micrograms/ml [65 to 105 mumol/l]); III--drowsiness, ataxia (11 to 15 micrograms/ml [45 to 65 mumol/l]); and IV--potentially catastrophic relapse (less than 11 micrograms/ml [45 mumol/l]). Pharmacokinetic studies revealed a prolongation of the CBZ half-life, elevation of the CBZ-epoxide/CBZ ratio, and emergence of CBZ-epoxide as a significant toxic metabolite. A treatment approach is proposed including repeated gastric lavage, detection of an insoluble tablet coagulum, electrolyte monitoring, avoidance of cathartics, and treatment of seizures with diazepam and phenytoin.

Adolescent↗
PubMed1988

Use of anginine.

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Angina Pectoris↗