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Biomedical subjects

A Davis

Publications and source records attributed to A Davis.

At least 415 records · Page 23Linked to original sources
PubMed1971

Evaluation of the Dirofilaria immitis filarial skin test antigen in the diagnosis of filariasis.

Conflicting opinions on the value of a skin test in the diagnosis of human filariasis emphasized the need for a careful examination of this procedure. The evaluation was made by asking workers in different countries to use an antigen prepared from Dirofilaria immitis in groups of people who could be examined for parasitic infection.In one non-endemic area, repeated tests over a 1-year period did not lead to sensitization, but the reactions of individuals varied from test to test. In endemic areas of filariasis, exposure to infective bites seemed to influence the pattern of skin reactions to a greater degree than did the development of overt infection with Wuchereria bancrofti. No particular size of reaction could be considered indicative of filarial infection.THE VALUE OF THE SKIN TEST WITH THIS ANTIGEN SEEMS LIMITED TO TWO SITUATIONS: (1) a large reaction may help to confirm a clinical diagnosis of filariasis when parasites cannot be found, and (2) the frequency distribution of skin reaction sizes in local populations may help, where blood surveys are impossible, to indicate areas in which some filarial infection is being transmitted.Results of skin test surveys should be expressed as frequency distributions of reaction sizes and negative/positive classification should be avoided.

Adolescent↗
PubMed1969

Bordetella pertussis serotypes in the United States.

To determine the Bordetella pertussis serotypes currently causing whooping cough in the United States, recently isolated cultures from different geographic areas were studied. Specific adsorbed antisera were prepared in our laboratory and used in both tube and slide agglutination tests. Among the 177 cultures isolated during 1966 and 1967 in seven states and one Canadian province, the predominant serotype was 1.3 (or 1.3.6), represented by 85% of the cultures. Fifteen cultures were serotype 1.2.3.4.6. The 376 cultures isolated in the Grand Rapids area during the last 30 years showed a changing pattern from serotype 1.2.3 during the early years to the currently prevailing 1.3 (or 1.3.6). During the 2-year study period, seven cultures of B. parapertussis were isolated in Michigan, and seven were received from other states. One culture of B. bronchiseptica, recovered from a child in Boston, was sent to us.

Agglutination Tests↗
PubMed1969

The effect of salt medicated with diethylcarbamazine in bancroftian filariasis.

The paper describes a trial conducted in Tanzania of the effect on bancroftian microfilaraemia of common salt medicated with diethylcarbamazine at a 0.1% (w/w) concentration, when given to a closed population of 600-700 with a known salt intake.After good observer agreement in microfilarial counting had been demonstrated, quantitative blood surveys were performed monthly on known carriers. Paired pretreatment microfilarial counts from the same patients at an interval of 4 months suggested a natural fluctuation in microfilarial densities and emphasized the need for parallel concurrent controls during treatment.During the trial the mean microfilarial densities fell steadily, being reduced by 73% at 3 months and 90% after 6 months. Tolerance to the drug-salt mixture was extremely good.Problems of planning, salt preparation and assessment of results are discussed and the importance of correct experimental design in future trials is stressed. The authors suggest that a trial of salt containing 0.2% (w/w) diethylcarbamazine may achieve optimum results. They point out that, while the use of diethylcarbamazine-medicated salt may prove useful in reducing transmission in closed communities or in endemic areas with no alternative source of salt, its extension to national populations as a sole means of bancroftian filariasis control would be of problematical value.

Diethylcarbamazine↗
PubMed1969

Metrifonate in urinary schistosomiasis.

This paper describes the effect of oral metrifonate, an organophosphorus cholinesterase inhibitor, on Schistosoma haematobium infections.The methodology of initial studies in hospital patients and 3 field trials in schoolchildren, using spaced doses ranging from 5 mg to 15 mg per kg of body-weight is detailed.The expected fall in plasma cholinesterase was confirmed. No major side-effects were encountered and minor symptoms were associated with high doses only.The optimum dose was 7.5 mg per kg, given once every 14 days or once monthly to a maximum of 3 doses if necessary. About two-thirds of patients were cured after 1 or 2 doses, but some 10% of these relapsed within 6 months of treatment. In 2 trials of this dose, cure rates of 71% and 79% were obtained.The authors conclude that metrifonate is a useful addition to oral schistosomicides for the treatment of S. haematobium infections in children, but suggest that more trials with spaced dose regimes are indicated and that further experimental studies are needed to define its mode of action.

Child↗
PubMed1969

Sulfonamides.

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Delayed-Action Preparations↗
PubMed1968

Comparative trials of antimonial drugs in urinary schistosomiasis.

Chemotherapeutic trials in urinary schistosomiasis are described and discussed. Their design and conduct were based on recommended statistical techniques, now generally accepted as the most appropriate approach to the assessment of antischistosomal drugs.Randomization produced comparable host groups in whom multiple parasitic infection and radiological urinary tract damage were common. Treatment was with one of three antimonial compounds given at equivalent metallic dosage daily.Antimony sodium tartrate (AST) and antimony dimercaptosuccinate (TWSb) were equally efficient curatively but both produced many side-effects. Sodium antimonylgluconate (TSAG) was four-fifths as effective but tolerance was superior. Estimations of urinary antimony excretion showed that tissue retention of the metal was related to cure-rates and side-effects. It was concluded that none of the drugs were suitable for mass chemotherapy.More new non-toxic schistosomicides are urgently needed and for their assessment, the setting-up of multicentre trials, following international agreement on technical methods, is suggested.

Adult↗