David Sixsmith

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Using an in vitro radioisotopic method, the activity was measured of proguanil, its metabolites cycloguanil and p-chlorophenylbiguanide (PBG), pyrimethamine, and chloroquine against seven Kenyan and three South East Asian strains of Plasmodium falciparum. Five Kenyan isolates were sensitive to both pyrimethamine and cycloguanil in vitro, while the Smith and(More)
Three tetrahydrofolate dehydrogenase (dihydrofolate reductase = EC 1.5.1.3) inhibitors were tested for antimalarial activity against Plasmodium falciparum, using an in vitro radioisotopic technique. Activity of each drug was tested in both normal RPMI medium 1640 and in modified medium (containing no p-aminobenzoic acid and 2.27 X 10(-8) M folic acid) after(More)
Studies were conducted in Malindi, Kenya, to assess the response of Plasmodium falciparum to chloroquine and amodiaquine in vivo (by an extended 14-day test) and in vitro (with the Rieckmann micro test). In-vivo resistance was demonstrated in 19 of 69 (28%) infections treated with chloroquine, but in only 2 of 60 (3.3%) of those treated with amodiaquine (p(More)
The aim of the project was to determine whether the rate of contaminant blood cultures could be reduced by using a team of dedicated phlebotomists. Comparisons were made between adult patients requiring blood cultures for suspected bacteremia on medical and surgical units before and after the introduction and withdrawal of a dedicated blood culture team.(More)
A useful in vitro method for field evaluation of Plasmodium falciparum sensitivity to pyrimethamine/sulfadoxine is described. Thirty-five Kenyan schoolchildren infected with P. falciparum were treated with this drug combination and followed up for 5 weeks. In vitro tests for sensitivity to these drugs and to chloroquine were performed before starting(More)
The present study details the development of a stress scale for medical personnel. The Medical Personnel Stress Scale is a 48-item subjective stress measure capable of assessing both organizational and individual dimensions of stress. It demonstrated both the ability to discriminate between divergent medical emergency room organizations and to predict self(More)
The response of Plasmodium falciparum isolates to dihydrofolate reductase inhibitors (DHFRI) was examined in Malindi, Kenya. All 20 infected children treated with pyrimethamine/sulphadoxine responded. In contrast, after treatment with pyrimethamine, parasitaemia in 9 of 14 infections failed to clear or recrudesced during the seven-day follow-up. In a(More)
  • D Sixsmith
  • 1977
Tablets have been prepared from previously characterized microcrystalline cellulose (Avicel) powders, using an instrumented single station tablet machine. The regenerated particle size was found to increase in compaction pressure. Compaction caused a slight initial decrease in B.E.T. surface area, followed by an increase mainly as a result of elastic(More)
The activity of pyrimethamine and sulfadoxine against two strains of Plasmodium falciparum has been studied in vitro by a radioisotopic technique. Low level antagonism of pyrimethamine resulted from the inclusion of p-aminobenzoic acid, p-aminobenzoylglutamic acid or folic acid in the test medium. Sulfadoxine activity was antagonised slightly by(More)
Two strains of Plasmodium falciparum were tested in vitro for sensitivity to the dihydrofolate reductase inhibitor pyrimethamine, the p-aminobenzoic acid (PABA) analogue sulfadoxine, and combinations of both drugs. One strain was sensitive and one resistant to pyrimethamine in vitro. Parasites cultured in medium containing neither folic acid nor PABA were(More)