PubMed Health⌕ Search

Biomedical subjects

B R Simpson

Publications and source records attributed to B R Simpson.

6 recordsLinked to original sources
PubMed1990

Production of 52Fe via proton-induced reactions on manganese and nickel.

Excitation functions for the production of 52Fe in the bombardment of Mn and Ni with protons were measured from threshold up to 200 MeV. Production rates of 52Fe as well as of its 55Fe and 59Fe impurities were also measured in specific energy windows ranging up to 100 MeV. The agreement with previous measurements, where available, is reasonably good, except that considerably higher 55Fe contamination levels than those recently reported below 70 MeV were obtained in the case of Ni. The experimental results were compared with theoretical calculations by means of the computer code ALICE/85/300. Overall agreement to within a factor of two was obtained, and the usefulness of the code in planning a radioisotope production process was demonstrated. Finally, practical production rates and impurity levels, obtained with a 66 MeV proton beam at high intensities (approximately 50 microA), are reported.

Iron Radioisotopes↗
PubMed1976

Unexplained hepatitis following halothane.

Full clinical and laboratory details of 203 patients with postoperative jaundice were submitted to a panel of hepatologists. All patients whose jaundice may have had an identifiable cause were excluded, which left 76 patients with unexplained hepatitis following halothane anaesthesia (UHFH). Hepatitis in 95% of these cases followed multiple exposure to halothane, with repeated exposure within four weeks in 55% of cases. Twenty-nine patients were obese, 52 were aged 41-70, and 53 were women. Thirteen patients died in acute hepatic failure. Rapid onset of jaundice after anaesthesia, male sex, and obesity in either sex were poor prognostic signs. Of the clinical stigmata of hypersensitivity, only eosinophilia was impressive. The UHFH group had a much greater incidence of liver kidney microsomal (LKM) and thyroid antibodies and autoimmune complement fixation than those patients whose jaundice related to identifiable factors. Thirteen of the 19 patients with LKM antibodies also had thyroid antibodies. In six patients retested two to three years later LKM antibodies had disappeared, although thyroid antibodies persisted. Rapidly repeated exposure to halothane may cause hepatitis, but such a complication is probably rare. Possibly obese women with a tendency to organ-specific autoimmunity may be more at risk. Nevertheless, the comparative risks of rapidly repeated halothane or non-halothane anaesthesia cannot be determined from the present data. If alternative satisfactory agents are available halothane should be avoided in patients with unexplained hepatitis after previous exposure, although in three to five patients with UHFH who were re-exposed to halothane jaundice did not recur.

Adolescent↗
PubMed1975

Human placental transfer of AH8165.

The human placental transfer of AH8165 (0times50times9 mg/kg) was studied in ten patients undergoing elective Caesarean section. There was no adverse effect on foetal movement attributable to placental transfer of the neuromuscular blocking drug. Bioassay of umbilical vein blood indicated that little AH8165 crossed the placenta. Studies using 3HAH8165 in two patients undergoing termination hysterectomy demonstrated transfer of only minute amounts of radioactivity to the foetus.

Apgar Score↗
PubMed1975

Intravenous anaesthesia by infusion. A technique using alphaxolone/alphadolone (althesin).

Two hundred and seventy-three patients were anaesthetised using aphaxolone/alphadolone as a sole anaesthetic agent, administered in either a 10% solution or in increments of neat drug. Analgesics were given where necessary. This technique was instituted to provide a method of anaesthesia that avoided pollution of the atmosphere, with its possible harmful effects. As experience was gained, better results were obtained. Overall, 86% of the anaesthetics administered were without problems, 12% presented some difficulty, usually minor movement of the patient, and in 2% this technique was abandoned.

Adult↗