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Biomedical subjects

C Harrison

Publications and source records attributed to C Harrison.

At least 91 records · Page 5Linked to original sources
PubMed1986

Philadelphia-positive metaphases in the marrow after bone marrow transplantation for chronic granulocytic leukemia.

A 28-year-old man with Ph-positive chronic granulocytic leukemia (CGL) was treated by high-dose chemoradiotherapy and transplantation of marrow cells harvested from his HLA-identical brother. One year after bone marrow transplantation (BMT) examination of his marrow showed a minority population of Ph-positive cells; their proportion subsequently fell such that 2 years after transplant analysis of marrow cells showed only cytogenetically normal cells. The patient remains clinically normal with a persisting mild lymphocytosis but without hematological evidence of leukemia. We cannot in this patient distinguish between persisting leukemia that later could no longer be recognized and relapse of leukemia that is now suppressed, perhaps only temporarily. This case emphasizes the need for caution in interpreting chromosomal finding after BMT for CGL.

Adult↗
PubMed1986

Alprazolam and lorazepam single and multiple-dose effects on psychomotor skills and sleep.

The effects of alprazolam 0.5 mg and lorazepam 2 mg on cognitive and psychomotor skills were assessed in twelve normal volunteer subjects in a randomised, double-blind, crossover design. Single and multiple dose effects were monitored using a battery of tests comprising critical flicker fusion threshold (CFFT), choice reaction time (CRT), simulated car tracking, and subjective ratings of perceived sedation (LARS) and of sleep behaviour (LSEQ). Compared with placebo baseline scores, treatment with lorazepam 2 mg (both single and multiple doses) resulted in a widespread impairment of CRT, tracking accuracy, and CFFT. Single doses of alprazolam 0.5 mg reduced CFFT with respect to the placebo baseline. Single and multiple dose treatment with both drugs resulted in subjective reports of sedation, a reduction of sleep onset latency, and improved sleep quality. Only lorazepam 2 mg significantly disrupted the integrity of behaviour on waking from sleep. These results suggest important pharmacodynamic differences between the two drugs in the doses used.

Adult↗
PubMed1986

Iron supplementation increases prevalence and effects of malaria: report on clinical studies in Papua New Guinea.

A placebo-controlled trial of intramuscular iron dextran prophylaxis for two-month-old infants was carried out on the north coast of Papua New Guinea where there is high transmission of malaria. The results indicate that the placebo group became relatively iron deficient whereas the iron dextran group had adequate iron stores and, in the absence of malaria, a higher mean haemoglobin. However in the iron dextran group there was a higher prevalence of malaria, as judged by parasite and spleen rates at 6- and 12-month follow-up; a lower haemoglobin associated with malaria when compared with the placebo group and a greater reticulocytosis in response to malaria infection. Within the placebo group it was noticed that the malaria rates were lower at follow-up in those infants who had had a low birth haemoglobin. In neither group was there apparent suppression of marrow activity in the presence of malaria. Malaria infection in both groups was associated with a significantly raised serum ferritin level and transferrin saturation. Over-all these data give evidence for a protective role of iron deficiency against malaria and would argue against the injudicious use of iron replacement in areas where malaria is endemic.

Clinical Trials as Topic↗
PubMed1986

Total dose iron infusion, malaria and pregnancy in Papua New Guinea.

A study was made of 544 mothers and their 556 newborns in an area of endemic malaria, to analyse effects of total dose intravenous iron infusion (TDI) to mothers during pregnancy. 34% of these mothers received TDI before delivery. A range of haematological tests was carried out on newborns and mothers in addition to anthropometry. 84% of mothers had had ante-natal care and data were also collected retrospectively from ante-natal records. TDI was associated with more slide positive peri-natal malaria in primipara (odds ratio: 5.46) but not in multipara. When all relevant factors were considered TDI was not associated with an overall improvement in haemoglobin status from the first ante-natal level recorded to the post-natal check. Post-natal malaria was associated with lower ante-natal and post-natal haemoglobin levels. There was no evidence of any effect of TDI in pregnancy or of maternal malaria on foetal maturity or birth weight. Gestational age, maternal weight, parity and maternal post-natal haemoglobin were all significantly correlated with birth weight. TDI to the mother was associated with higher neo-natal serum ferritins and lower neo-natal haemoglobins. Maternal post-natal malaria was associated with significantly lower iron in serum in newborns. It is suggested that routine total dose iron infusion to anaemic pregnant mothers in malaria endemic areas may be contraindicated.

Anemia, Hypochromic↗
PubMed1986

Cyclosporine and the ischemic rat kidney.

The effects of cyclosporine (CsA) on renal function and morphology have been studied in the rat after unilateral nephrectomy and warm renal ischemia. There is evidence of an enhanced CsA nephrotoxic effect after unilateral nephrectomy alone and of an additive or synergistic effect of CsA and renal ischemia upon renal function and morphology. These enhanced effects are most evident after longer periods of ischemia (60 min) and with higher doses of CsA (25 mg/kg/day). The findings may be relevant to clinical practice and suggest that the nephrotoxic effects of CsA upon the donor kidney may be greatest when there is coincident renal damage from other causes.

Animals↗
PubMed1985

Residual effects of zopiclone and benzodiazepine hypnotics on psychomotor performance related to car driving.

A double-blind, randomized, cross-over study was carried out in 10 normal healthy volunteers to investigate the residual effects of 7.5 mg zopiclone, 1 mg lormetazepam, 0.25 mg triazolam, 1 mg flunitrazepam and placebo. Tests of psychomotor performance and analogues of car driving ability were administered the morning following night-time medication. Changes with respect to placebo in an information-processing task one hour after taking the medications confirmed the hypnotic efficacy of zopiclone, triazolam and flunitrazepam. Flunitrazepam also produced a significant depression of the Critical Flicker Fusion Threshold (CFF) and increased subjective ratings of sedation one hour after nocturnal dosing. Flunitrazepam impaired the reaction time on the information-processing test the morning following doses of 1 mg.

Adult↗
PubMed1984

Iron and infection in infancy--report on field studies in Papua New Guinea: 1. Demographic description and pilot surveys.

Madang district was selected for a longitudinal study of the effects of iron prophylaxis on infectious morbidity in infancy and the topography, climate, domicile, ethnology, demography, disease patterns, nutrition and health services of the district are described. The area has a tropical, humid climate and a mixed economy. Pneumonia was the main killing disease at all ages, and malaria was endemic. A base hospital and well organized maternal and child health services ensured that morbidity surveillance would be optimal. Pilot haematological surveys confirmed a high incidence of anaemia in infancy. Mean haemoglobin between nine and 52 weeks of age was 8.6 g/dl. Results suggested that malaria and iron deficiency were important causes of this anaemia.

Age Factors↗
PubMed1984

Iron and infection in infancy--report on field studies in Papua New Guinea: II. Protocol and description of study cohort.

The protocol for a prospective, randomized, double-blind, placebo controlled trial of iron prophylaxis in infants is described. Specific design points discussed include (i) control and "blind", (ii) dose, preparation and age of administration of iron, (iii) standardization of morbidity recording, (iv) data analysis and (v) ethics. The study cohort at birth is described and rationale for exclusions and reasons for withdrawals are discussed. An initial descriptive comparison is made of treatment and control groups entering the trial at two months of age.

Age Factors↗
PubMed1984

Automated extraction of drugs from biological fluids.

An automated continuous flow liquid-liquid extraction procedure is described for the separation of the H2-antagonist loxtidine from plasma samples containing two metabolites which interfere in the radioimmunoassay of the drug. The extraction of the bronchodilator salbutamol was studied using the DuPont Prep I automated liquid solid extraction apparatus, with a 12 cartridge capacity, and a vacuum extraction box designed in this laboratory to hold 30 Sep-pak C-18 (Waters Associates) cartridges. Twenty-four plasma samples per hour can be automatically processed with the Prep I. Although the vacuum box is not fully automated 45 plasma samples per hour can be processed. The Prep I can only be used with DuPont XAD, strong cation and anion exchange cartridges. Cartridges containing alumina, silica, florisil, cation and anion exchange resins and reverse phase packings can all be used with the vacuum extraction box. The latter costs only a fraction of the Prep I and therefore each analyst can have his own unit.

Acetates↗
PubMed1984

The readability of health-care literature.

The readability of health-related pamphlets intended for the British public was compared with that of English national newspapers. Many of the pamphlets were found to be less readable than desirable. Pamphlets issued by government departments (principally the Department of Health and Social Security) were assessed as particularly difficult to read, but some specialist and commercially produced pamphlets also gave cause for concern. A small number of specially produced 'baby books' were found to have more suitable levels of prose difficulty. It is suggested that readability formulae can be a useful tool in the initial assessment of health education literature.

Child↗
PubMed1983

Plasma ranitidine concentrations after intravenous administration in normal volunteers and haemodialysis patients.

A comparison was made of the plasma concentrations of ranitidine base in 12 normal volunteers after the administration of 100 mg intravenously and in 6 patients with terminal renal failure after 40 mg intravenously off and then during haemodialysis. The plasma ranitidine concentrations were determined by radioimmunoassay. The results suggest that reduced elimination of the drug occurs in patients with severe renal failure and that there is significant removal of the drug during haemodialysis. It is suggested that dosage reduction is advisable in patients with severe renal failure and a suitable schedule for such patients is described.

Furans↗
PubMed1981

Gastric acid response to topical or intravenous histamine and topical H2-receptor blockade in dogs.

This study was undertaken to determine gastric acid surface and to examine the local effect f ranitidine, a histamine H2-receptor antagonist, on the gastric acid response to histamine. Histamine applied to the Heidenhain pouch (HP) mucosa resulted in a slight and dose-dependent stimulation of acid secretion without affecting acid secretion from the main stomach. Ranitidine given into the HP caused dose-dependent inhibition of the HP response to topical or intravenous histamine without affecting the acid response of the main stomach and without any significant change in the serum ranitidine level. Ranitidine applied to the main stomach with the pylorus occluded inhibited histamine-induced acid secretion also without any increase in the serum ranitidine level. This inhibition was about 30% of that obtained with the same dose of ranitidine given into the stomach with the pylorus left open during the experiment. This study provides evidence that topical histamine is a weak stimulant of gastric secretion and that topical ranitidine is capable of local inhibition of the acid response to both topical and intravenous histamine.

Administration, Topical↗
PubMed1980

Ranitidine--a new H2-receptor antagonist.

The pharmacokinetics and gastric antisecretory effects of a new histamine H2-receptor antagonist, ranitidine hydrochloride, have been investigated in healthy subjects. In the pharmacokinetic study six subjects received 20 mg, 40 mg, and 80 mg ranitidine, both orally and intravenously. Plasma levels of ranitidine were dose-related and in most subjects after oral drug the concentration time curve was bimodal. The estimated elimination half-life was 140 minutes and the bioavailability of the oral drug was about 50%. Five subjects received bolus intravenous injections of ranitidine 20 mg, 40 mg, and 80 mg during continuous gastric stimulation with pentagastrin. There was a dose-related reduction in acid output (P less than 0.05).

Adult↗
PubMed1976

Affinity of labetalol for ocular melanin.

1 The toxicity of labetalol has been studied in mice, rats, rabbits, and dogs, and reproductive studies have been carried out in rats and rabbits. Nothing was observed in any of these species to suggest that patients taking labetalol might be exposed to any toxic hazard. 2 During the reproductive studies 14C-labetalol was used to study placental transfer. Radioactivity was present in the uveal tract of the foetal eye. 3 Radioactive labetalol but not its metabolites was bound to the melanin pigment of the eye. This binding was reversible. It was not possible to saturate the melanin of the cat and dog eye even with prolonged dosing with labetalol. 4 Chloroquine, given orally at doses of 1.5-6 mg/kg/d for 4-7 weeks, produced changes in the cat retina. When oral doses of 20 mg labetalol/d were given to cats for 7 months, no oculotoxic effects were observed. 5 Detailed ophthalmological and histological examinations were carried out on the rats, rabbits, cats and dogs used in these studies. No changes indicative of oculotoxicity were observed. In the reproductive studies no effects were observed in the developing rat or rabbit eye, which could be consequent on the placental transfer of labetalol or its metabolites.

Administration, Oral↗