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Biomedical subjects

R F Sturrock

Publications and source records attributed to R F Sturrock.

At least 91 records · Page 5Linked to original sources
PubMed1977

Eosinophilia in Kenyan baboons (Papio anubis) induced by Trichinella spiralis and Schistosoma mansoni.

High primary doses of Trichinella spiralis administered orally to Kenyan baboons (Papio anubis) induced a marked but unpredictable eosinophilia which started 2--3 weeks after infection and persisted as erratic waves for at least 6 months. Low primary oral doses induced no eosinophilia but a later, high challenge gave an accelerated eosinophilic response, although the peak was lower than in high primary infection. Intravenous injection of infective T. spiralis larvae resulted in a predictable, rapid eosinophilic response which persisted for several weeks. Intravenous injection of a particulate material, Sepharose, gave no oesinophilic response. Percutaneous Schistosoma mansoni infection of baboons resulted in a two-stage eosinophilic response: an initial rise occurred about 2/3 of the way through the pre-patent period and was followed by a second rise at the onset of patency. After peaking, the eosinophilia waned erratically over the next 3 or 4 weeks. A strong antibody response, measured by countercurrent immunoelectrophoresis, was given in oral infections with T. spiralis, but intravenous injections elicited little or no antibody formation. Parasitological evidence indicated no cross-resistance to S. mansoni in baboons injected with T. spiralis 9 days previously. Thus, the intravenous injection of infective T. spiralis larvae appears to be a suitable method of inducing experimentally a non-specific eosinophilia to investigate possible immune mechanisms to S. mansoni in the baboon.

Animals↗
PubMed1977

Preliminary trials against Biomphalaria glabrata of a new molluscicide formulation: geletin granules containing Bayluscide wettable powder.

Tests were conducted with gelatin granules containing Bayluscide (niclosamide) w.p., 23-3% w/w a.i. Granules rendered a simulated field habitat (banana drain) lethal to Biomphalaria glabrata for 40 days when applied at a rate calculated to give 5 mg/1 in the water. At this dose, Bayluscide e.c. was effective for 8-12 days. Granules exposed to various combinations of natural or simulated tropical climatic factors for up to 56 days gave variable kills of snails, apparently unrelated to the factors tested. The rate at which the molluscicide was released from the granules was affected by climatic factors: high temperatures and low humidities slowed the rate, probably by hardening the granules; rainfall and high humidities accelerated the rate, probably by softening or disintegrating the granules. There was no apparent loss of molluscicidal activity in granules exposed for 56 days to various combinations of climatic factors. The results suggest that this formulation may be applied during droughts to temporary habitats when these are dry and accessible. The molluscicide would then be released at the unpredictable start of the next wet season and kill any snails which survive the drought by aestivation.

Animals↗
PubMed1977

Antibody-dependent, eosinophil-mediated damage to 51Cr-labeled schistosomula of Schistosoma mansoni: effect of metabolic inhibitors and other agents which alter cell function.

The effect of drugs known to inhibit different metabolic pathways or cell functions on antibody-dependent, eosinophil-mediated damage to schistosomula was determined. Eosinophil-mediated damage was completely inhibited by cytochalasin B, inhibitors of glycolysis, aminophylline, and treatment of cells with diazotized sulfanilic acid and tosyl-lysyl-chloromethyl ketone. The effects of cytochalasin and 2-deoxyglucose were reversible. On the other hand, eosinophil-mediated damage was unaffected by agents which inhibit DNA replication, protein synthesis, oxidative respiration, prostaglandin synthesis, and microtubule aggregation. The findings suggest that alteration of the cell surface membrane and microfilaments prevents damage by interfering with cell-target interactions, that energy derived from glycolysis is required for cytotoxicity, that cell-associated esterases are probably involved, and that cytotoxicity may be modulated by cyclic nucleotides. Some of the attributes of eosinophils that allow it and not other cells to mediate this reaction are discussed.

Animals↗
PubMed1977

Kidney lesions in baboons infected with Schistosoma mansoni.

Glomerular lesions in baboons (Papio anubis) infected with different dosage regimes of Schistosoma mansoni were studied by immunofluorescence and light microscopy on kidney sections and by countercurrent immunoelectrophoresis on kidney homogenates and tissue eluates. Mild lesions, characterized by focal and segmental deposits of immune complexes, developed in sixty-two out of 103 baboons, irrespective of the intensity and duration of the infection. Severe, diffuse lesions developed in six baboons after prolonged and heavy infections. Adult worm and soluble egg antigens, together with IgM, IgG and C3, were detected in most of the severe lesions and in some of the mild lesions. In some animals, antigens were detected in most of the severe lesions and in some of the mild lesions. In some animals, antigens were detected in acid homogenates and eluates of kidneys which showed no deposits of immunoglobulins or complement. These observations indicate that renal lesions in S. mansoni infections may be attributable to the deposition of immune complexes pre-formed in the circulation. However, the demonstration of antigens alone in some animals may suggest an alternative possibility, namely that antigens are deposited first with a subsequent binding of antibody and complement.

Animals↗
PubMed1976

Schistosoma mansoni in the baboon (Papio anubis): parasitological responses of Kenyan baboons to different exposures of a local parasite strain.

The course of infection with a local strain of Schistosoma mansoni was investigated in Kenyan baboons (Papio anubis). A single exposure to 5000 cercariae per baboon (cpb) killed five 4-8 kg baboons; a sixth survived the full 30-week post-exposure period, with suppressed egg production after week 11. Lower doses were not lethal. A single exposure to 1000 cpb gave satisfactory adult worm recoveries, high and steady faecal egg excretion, and a high tissue egg recovery, predominantly from the large intestine. A similar but less consistent picture was obtained with a single exposure to 200 cpb. Baboons receiving 5 monthly exposures of 200 cpb (1000 cpb total) showed some evidence of the development of protective immunity. Three animals showed patterns resembling those for 200 and 1000 cpb. The other 3 had suppressed egg production (faecal and tissue) indicating, perhaps, some immunological process. They also had an abnormally high percentage of eggs in the liver.

Animals↗
PubMed1976

Studies on the hatchability of Schistosoma mansoni eggs from a naturally infected human community on St Lucia, West Indies.

A relatively simple, standardized hatching test was devised, tested and used to estimate the Schistosoma mansoni hatching rate for 88 St Lucian subjects selected by age, sex and intensity of infection. The hatching rate was dependent on the intensity of infection and rose proportionately with it. The rate also decreased with increasing age of the subject. Sex alone had no direct effect but there was a suggestion of an interaction between sex and age. These results suggest that several hatching tests are necessary, before and after treatment in schistosomicidal drug trials, to permit valid conclusions to be drawn. The hatching data are used in conjunction with survey results to calculate the contamination potential of different age groups in a population. School children (5-14 years old) are about twice as important as young adults (15-29 years old) who, nevertheless, contribute over a quarter of the total contamination potential. However, whereas school children are fairly accessible for mass chemotherapy control programmes, young adults often are not and, furthermore, involve problems associated with the treatment of women of child-bearing age.

Adolescent↗
PubMed1976

Renal capillariasis in the small Indian mongoose, Herpestes auropunctatus.

A Capillaria sp. was recovered from the kidneys of 28 (93.3%) of 30 small Indian mongooses (Herpestes auropunctus) collected in St. Lucia, West Indies. The nematodes were embedded within distended pelvic fornices of the kidney and surrounded by accumulations of eggs. A chronic, low-level inflammation of the transitional epithelium was characterized by hyperplasia, giant cells surrounding embedded eggs and a plasmacytic infiltration. This is the first record of a capillarid nematode from the kidney of the mongoose.

Animals↗
PubMed1976

Schistosoma mansoni in baboons. Antibody-dependent cell-mediated damage to 51Cr-labelled schistosomula.

A technique is described for estimating cell-mediated damage to the larval stages of Schistosoma mansoni that occur in the mamalian host (schistosomula), by measuring release of 51Cr from labelled organisms. This technique, although widely used for assaying cytotoxicity to single cell suspensions or monolayers, has not previously been applied to a multicellular parasite. It is more objective than microscopical assays, and allows the processing of larger numbers of samples. The new method has been used for the detection and quantification of cell-dependent cytotoxic antibodies in infected baboons. The effector cell in normal baboon peripheral blood, as in man, is associated with a neutrophil- and eosinophil-enriched fraction. Cytotoxic antibodies appear in the serum about 4 weeks after a primary infection, rising to a peak at 7-10 weeks, and then declining. In some animals, a second rise towards 30 weeks was observed. There were no consistent differences between groups of baboons exposed to 1000 cercariae, 200 cercariae, and 200 cercariae administered at each of five monthly intervals. The possible relationship between cell-dependent cytotoxic antibodies and resistance to reinfection in infected animals is discussed.

Animals↗
PubMed1975

Distribution of the snail Biomphalaria glabrata, intermediate host of Schistosoma mansoni, within a St Lucian field habitat.

A total of 6360 mud samples were obtained, in 62 collections made with an exhaustive sampling device, from banana drains on the West Indian island of St Lucia during fortnightly samplings over a 2(1/2)-year period. Analysis of counts of the snail Biomphalaria glabrata from these samples showed that this species had a contagious distribution. This finding is consistent with other evidence that banana drains form a rigorous habitat for B. glabrata. Its distribution was more contagious than that of Oncomelania quadrasi in certain Philippine habitats and several species of aquatic snail in various African irrigation canals. The exact transformation for normalizing the snail counts for standard statistical techniques was z = x(0.287) but the more convenient cube root transformation is probably adequate. However, if too few snails are collected (15 or fewer per 100 samples) or if the frequency distribution of snail counts is discontinuous, with too many widely separated high frequency counts, neither transformation will be entirely satisfactory.

Animals↗