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Biomedical subjects

R S Desowitz

Publications and source records attributed to R S Desowitz.

At least 19 recordsLinked to original sources
PubMed1992

Placental Plasmodium falciparum parasitaemia in East Sepik (Papua New Guinea) women of different parity: the apparent absence of acute effects on mother and foetus.

The effects of malaria were studied in a group of parturient women of East Sepik Province, Papua New Guinea. Further information was gathered from a search of hospital records and interviews with village aid post orderlies. Examination of placental blood revealed a Plasmodium falciparum parasitaemia rate of 41% of the primiparae, 23% in parous 2, 25% in parous 3, and 3% in multiparae greater than 3. Approximately one-half of those with placental parasitaemia had a concomitant detectable peripheral parasitaemia. Placental parasitaemias were of relatively low density, averaging 1.6%. There were no instances in the observed series of births, hospital records, or village studies of the occurrence of severe malaria in the mother or its acute effects on the foetus. Neither birthweight nor maternal or cord blood haematocrit was related to the presence or absence of placental parasitaemia. Neonatal birthweight and risk of delivering a low birthweight (less than 2.5 kg) baby was statistically associated only with maternal parity. The possible reasons for the relatively benign effect of malaria in the pregnant women of this population are discussed.

Acute Disease↗
PubMed1992

Placental pathology in Plasmodium berghei-infected rats.

The pathologic changes in placentae of pregnant rats infected with Plasmodium berghei at different stages of gestation were studied using light and electron microscopy and immunohistochemistry. The major changes observed were thickening and duplication of the trophoblastic basement membrane, and accumulation of parasitized erythrocytes and occasional mononuclear cells in the maternal blood space. Immunohistochemical examination of nine placentae revealed that six stained positively for IgG, two for IgM, and four for P. berghei antigen. No C3 deposition was detected. The findings in this study indicate that the variable parasitologic-clinical course from benign to fatal of P. berghei infection in pregnant rats makes it a potentially valuable model of human gestational malaria infection.

Animals↗
PubMed1992

Prenatal immune hypersensitization to malaria: Plasmodium falciparum-specific IgE antibody in paired maternal and cord sera from Papua New Guinea.

In a study of malaria and pregnancy in East Sepik Province of Papua New Guinea 45 maternal and cord serum pairs were tested for Plasmodium falciparum-specific IgE antibody. There were 17 positive sera: 6 cases of maternal serum alone, 5 cases of cord serum alone and 3 pairs of maternal and cord sera. IgE antibody positivity rates in the mothers increased with parity, whereas placental parasitaemia rates decreased. Cord serum positivity was not affected by parity. Immunoblots of the sera revealed a diversity of IgE antibodies to specific antigens of the P. falciparum lysate, but an IgE antibody to a 48kd antigen was present in all positive maternal and cord sera.

Animals↗
PubMed1989

Characterization of a model of malaria in the pregnant host: Plasmodium berghei in the white rat.

This study characterizes a Plasmodium berghei white rat model of P. falciparum malaria in the pregnant human. Seventy-day-old and 114-day-old female rats, given an infecting inoculum at time of mating, had higher parasitemias and a more severe anemia than age- and sex-matched controls. Under these experimental conditions, the parasitemia went to crisis in all animals and there were no fatal infections. In contrast, all animals died when the infection was initiated 7 days after conception, a timing that brought a coincidence of peak parasitemia and term. Pregnancy during the post-crisis subpatent period did not cause recrudescence. At the time of delivery, the parasitemia was consistently higher in the placental (crush smear) blood than in the peripheral (tail) blood. This difference was greatest in animals giving birth shortly before or 1-2 days after the parasitemic crisis. Very young, compact parasite forms predominated in the placental blood, whereas trophozoites predominated in the peripheral blood.

Age Factors↗
PubMed1988

Prenatal immune priming in malaria: antigen-specific blastogenesis of cord blood lymphocytes from neonates born in a setting of holoendemic malaria.

The Plasmodium falciparum-specific blastogenic response of cord blood lymphocytes (CBLs) from neonates born in an area of holoendemic malaria of Papua New Guinea was compared to that of CBLs from neonates born in Hawaii, where malaria transmission does not occur. The average blastogenesis stimulation index of the New Guinea CBLs was 4.5 times greater than that of the Hawaiian group of samples. Eight of the 24 New Guinea CBL samples had a stimulation index greater than ten and counts per minute ranging from 13,331-84,242, whereas all the Hawaiian CBL samples had a stimulation index less than four, and the highest count per minute was 2016. The data are interpreted as indicating that prenatal immune sensitization/priming to P. falciparum had occurred in some of the New Guinea neonates.

Animals↗
PubMed1978

Studies with Brugia pahangi. 16. Precipitation antibody in infected cats detected by counterimmunoelectrophoresis.

In cats infected with normal, or irradiated, infective (L3) larvae of Brugia pahangi counterimmunoelectrophoresis revealed the presence of antibody to soluble antigens derived from microfilariae, adults and infective larvae of the same parasite. Infected cats with a persistently high to moderate microfilaraemia gave positive precipitin reactions to L3, microfilarial and adult worm antigens. Cats which had become amicrofilaraemic had antibody to L3 and microfilarial antigens but not to adult worm antigen. Serum from cats inoculated with irradiated L3 larvae produced a precipitin reaction only to the L3 antigen.

Animals↗
PubMed1978

Rapid decrease of precipitating and reaginic antibodies in Dirofilaria immitis-infected dogs which develop severe adverse reactions following treatment with diethylcarbamazine.

Dirofilaria immitis-infected dogs were treated with diethylcarbamazine. Measurement of the level of IgG precipitating antibody was carried out by counterimmunoelectrophoresis and that of IgE by passive cutaneous anaphylaxis in pre-treatment and post-treatment serum samples. In dogs showing severe to moderate adverse reactions to the drug there were pronounced decreases of both antibodies to a "metabolic" antigen prepared from the medium in which adult female worms had been incubated. These antibody levels did not decline in non-reacting dogs. Precipitating antibody levels to somatic antigens extracted from adult worms and microfilariae remained unaltered in both reactive and non-reactive animals.

Animals↗
PubMed1977

Studies on parasitic crisis in malaria: I. Signs of impending crisis in Plasmodium berghei infections of the white rat.

White rats infected with Plasmodiam berghei were observed throughout the course of infection for indicators of impending crisis (penultimate stage). Two ratios, percentage young compact forms:percentage trophozoites and percentage reticulocytes:percentage parasitaemia, were reliable markers of the penultimate period and impending crisis. When the percentage young compact form:percentage trophozoite ratio exceeded 1.0 and was coincident with an increase of uninfected reticulocytes in the circulation (as given by a percentage reticulocyte:percentage parasitaemia ratio greater than 1.0) the parasitaemic decline of crisis consistently occurred 24-48 hours later.

Animals↗
PubMed1977

Observations on the application of counterimmunoelectrophoresis for the seroepidemiology of human cysticercosis.

An immunoepidemiological survey for cysticercosis was carried out in an endemic focus of Irian Jaya by use of a counterimmunoelectrophoresis (CIEP) technique. All individuals with palpable subcutaneous cysticerci were serologically positive by this technique as were 77.3% of the individuals giving a history of epileptiform seizures and 22.5% with no clinical complaints. The possible application of CIEP for epidemiological surveillance is discussed.

Adolescent↗
PubMed1976

The detection of antibodies in human and animal filariases by counterimmunoelectrophoresis with Dirofilaria immitis antigens.

Counterimmunoelectrophoresis revealed the presence of precipitin antibody in all of 6 dogs and the 1 cat infected with Dirofilaria immitis and in the serum of 17 of 24 individuals living in a setting of hyperendemic subperiodic bancroftian filariasis. Antigens used in the test were prepared from microfilariae and adult male D. immitis. Some humans and animals had antibodies to both antigens while others had antibodies against microfilariae or adult worms only. The presence of soluble circulating antigen was detected in the sera of two dogs with high microfilaraemias.

Animals↗
PubMed1976

Hyperendemic subperiodic Bancroftian filariasis: a search for clinical and immunological correlates of microfilaraemia.

A study was carried out in the Kingdom of Tonga, an area of hyperendemic Bancroftian filariasis, to determine whether correlations could be made between microfilaraemia, as diagnosed by membrane filter concentration, and immunological (skin test, immunoglobulin levels) or clinical findings. There was no relationship between the presence or degree of microfilaraemia and any clinical manifestation or skin test reaction. The skin test positivity rate for microfilaraemic and amicrofilaraemic individuals was approximately the same for all age groups. Among those aged 0 to 4 years, 48% of microfilaria positives were negative in the skin test. The highest average IgG and IgE levels were found in the groups with the highest microfilarial densities, i.e., in children with a history of fever and in adults with a history of lymphangitis/lymphadenitis. Over a period of a year, the microfilarial density changed significantly in 18 (34%) of 53 adults.

Adolescent↗