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Biomedical subjects

J Lebras

Publications and source records attributed to J Lebras.

At least 19 recordsLinked to original sources
PubMed2005

[Congenital malaria as a result of Plasmodium malariae in an infant born to a HIV-seropositive woman].

Congenital malaria is uncommon in France. The purpose of this report is to describe a case involving a six-week-old infant who was hospitalized with fever, hepatosplenomegaly, anemia and thrombopenia. Thick and thin blood smears were positive for Plasmodium malariae. The infant responded favorably to chloroquine. Based on this experience, we performed a search of the literature to find case reports on congenital malaria in France and compare clinical and epidemiologic data with series reported in the United States and from endemic areas. The placenta appears to provide an effective barrier against Plasmodium since infection is much more common than disease. The delay for onset of clinical symptoms is longer in temperate zones than in endemic areas. The type of parasite could account for this difference since African congenital malaria are due to Plasmodium falciparum while most cases described in the United States are due to Plasmodium vivax. We also discuss the possible implications of coinfection by HIV in the mother.

Antimalarials↗
PubMed1999

Immunocapture diagnostic assays for malaria using Plasmodium lactate dehydrogenase (pLDH).

We have developed two diagnostic assays based on the specific detection of Plasmodium lactate dehydrogenase (pLDH) activity. These assays exploit a panel of monoclonal antibodies that capture the parasite enzyme and allow for the quantitation and speciation of human malaria infections. An immunocapture pLDH activity assay (ICpLDH) allows for the rapid purification and measurement of pLDH from infected blood using the NAD analog APAD, which reacts specifically with Plasmodium LDH isoforms. An immunochromatographic test (the OptiMAL assay) was also formatted and allowed the detection of parasite infections of approximately 200 parasites/microl of blood. By using a combination of antibodies, both tests can not only detect but differentiate between P. falciparum and non-P. falciparum malaria. Both assays show a sensitivity comparable with other commercial nonmicroscopic tests; importantly, we found very few instances of false-positive samples, especially with samples from patients recently cleared of malaria infection. Furthermore, we find that when one uses the quantitative ICpLDH assay, the levels of pLDH activity closely mirror the levels of parasitemia in both initial diagnosis and while following patient therapy. We conclude that diagnostic tests based on the detection of pLDH are both sensitive and practical for the detection, speciation, and quantitation of all human Plasmodium infections and can also be used to indicate drug-resistant infections.

Animals↗
PubMed1996

Response to fluconazole by 23 patients with human immunodeficiency virus infection and oral candidiasis: pharmacological and mycological factors.

The MICs of fluconazole for strains of Candida species and the levels of fluconazole in serum were determined at day 0 and day 14 for 23 human immunodeficiency virus-infected patients with oral candidiasis who were treated orally with 100 mg of fluconazole per day for 14 days. Among the 23 patients, 11 (48%) were not clinically cured and had persistent isolation of Candidiasis albicans (n = 10) and/or presence of non-C. albicans (n = 6). Clinical response could be predicted by the susceptibility of the strain to fluconazole determined at day 0. All 12 patients who were cured were infected with a strain for which the MIC was < 0.78 mg/liter. All four patients who were infected with a strain for which the MIC was > 3.12 mg/liter experienced clinical failure. These data suggest that a C. albicans strain could be defined as being susceptible when the MIC of fluconazole is < 0.78 mg/liter and as being resistant when the MIC is > 3.12 mg/liter.

AIDS-Related Opportunistic Infections↗
PubMed1990

Activities of pefloxacin and ciprofloxacin against experimental malaria in mice.

We investigated the in vivo antimalarial activities of pefloxacin and ciprofloxacin in Swiss albino mice infected intravenously with 5 x 10(6) Plasmodium yoelii N67 parasites 1 h before treatment. Groups of 20 mice received a subcutaneous injection of 40, 80, or 160 mg of ciprofloxacin or pefloxacin per kg of body weight every 8 h for 3 days. Parasitologic activity was assessed on day 4, and survival was assessed on day 21. Control mice had a fulminant course with a parasitemia of 61.3% +/- 12.1% on day 4, and 90% of the mice were dead on day 21. The lower dosages of pefloxacin and ciprofloxacin (40 and 80 mg/kg) were not efficient. With 160 mg/kg, ciprofloxacin achieved an 85.8% reduction in parasitemia and 17 of 20 mice survived. Pefloxacin achieved a 92.8% reduction in parasitemia, and all mice survived. All treated, noninfected control mice survived. With ciprofloxacin, the antimalarial activity was similar with injections of 240 mg/kg every 12 h but was strongly diminished with injections of 160 mg/kg every 12 h. With pefloxacin, similar activities were observed with injections of 160 mg/kg every 8 h or injections of 160 or 240 mg/kg every 12 h. With both drugs, this activity was highly reduced when the treatment was delayed by 24 h. This underlines the need to provide treatment within the first hours after infection to achieve an optimal effect in this rapidly lethal experimental model of malaria. Pefloxacin and, to a lesser extent, ciprofloxacin are potent antimalarial drugs which might prove useful in the treatment of less rapidly aggressive human malaria.

Animals↗
PubMed1989

Divided-dose kinetics of mefloquine in man.

The kinetics of mefloquine was investigated following oral divided-doses in 10 healthy Caucasian volunteers. They received 500 or 750 mg followed by 500 mg 8 h later. Unchanged mefloquine (M) and its carboxylic acid metabolite (MM) were measured in whole blood and plasma for 50 days by h.p.l.c. Maximum blood and plasma M concentrations of 1872 +/- 362 ng ml-1 (mean +/- s.d.) and 1900 +/- 434 ng ml-1, respectively, were found within 6-10 h after the second dose. The terminal plasma elimination half-life was 20.1 +/- 3.7 days (mean +/- s.d.) and the oral clearance was 22.3 +/- 6.7 ml h-1 kg-1 (mean +/- s.d.). Plasma concentrations of MM exceeded those of M by 2-3 fold within 2 days. The whole blood concentration of MM was lower than that in plasma but also exceeded the whole blood concentration of M.

Adult↗
PubMed1986

Role of immune serum and complement in stimulation of the metabolic burst of human neutrophils by Plasmodium falciparum.

Interaction between human neutrophils (polymorphonuclear leukocytes [PMN]) and Plasmodium falciparum in the natural defense of the host remains to be elucidated. In patients with acute malaria, oxygen consumption (QO2) of PMN at rest and after stimulation by zymosan was significantly increased compared with that in the controls. With 10% immune serum, both QO2 and chemiluminescence of normal PMN were significantly increased after stimulation by a P. falciparum erythrocyte culture. This activation was not observed with a nonparasitized erythrocyte culture and was correlated with parasitemia. Immune serum and complement were required to trigger this metabolic activation of normal PMN. With normal serum or heat-inactivated immune serum, a parasitized erythrocyte culture did not significantly stimulate QO2 or chemiluminescence of normal PMN. The classical complement pathway was essential for this stimulation, whereas the alternate pathway was less involved. Hyperimmune sera from subjects residing in endemic areas were more able to trigger the metabolic burst than were immune sera from subjects from other sources. The use of synchronous cultures showed that PMN were more stimulated by cultures rich in merozoites than by the same cultures which contained only intraerythrocytic forms. Giemsa staining showed granules of hemozoin and occasional merozoites or parasitized erythrocytes within PMN. This increase in production of activated oxygen radicals could damage intra-or extraphagocytic parasitic forms. As P. falciparum is sensitive to oxidant stress and PMN is the phagocyte with the most intense metabolic burst, the role of PMN in defense against malaria should be considered.

Antigen-Antibody Complex↗
PubMed1981

Cryoglobulins, circulating immune complexes, and complement activation in cerebral malaria.

A total of 32 patients with Plasmodium falciparum malaria were studied. Of these, 23 had benign infections, and 9 had typical cerebral malaria. Cryoglobulins, circulating immune complexes detected by a C1q-binding assay, and hypocomplementemia were found in eight of nine patients with cerebral malaria. Raised levels of complement component 3 breakdown products (C3d) were found in the seven patients tested. Peak levels of circulating immune complexes and C3d were associated with thrombocytopenia. In contrast, in patients with benign Plasmodium falciparum malaria, cryoglobulins and circulating immune complexes were found only in 3 of 23 patients. Similarly, hypocomplementemia was detected only in 5 of 23 patients. These observations suggest that the intensity of the immune response and of the associated complement activation may be important factors in the pathogenesis of cerebral malaria.

Adult↗
PubMed1980

[Angiographic exploration of a case of a case of adrenal APUD adenoma secreting three hormones: VIP, catecholamines, and somatostatin (author's transl)].

An APUD adenoma of the right adrenal was discovered in an adult after angiography and compted tomography The tumor had provoked a WDHH syndrome. Selective venous sampling before operation demostrated the presence in the tumor of hormonal secretions (VIP and catecholamines). The patient recovered after excision of the tumor, which contained large quantities of intracellular somatostatin and VIP.

Achlorhydria↗
PubMed1978

Hepatitis B antigenaemia on Wuvulu Island.

A survey of the population of Wuvulu Island was undertaken to determine the prevalence of hepatitis B antigenaemia (HBsAg). Seventy-five percent of the population were tested, and 17.7% of those tested were positive for HBsAg. The percentage of positive sera increased with age but declined in the 5th decade of life. There was a marked difference in positivity between the two villages on the island (25.9% and 9.9%) which cannot be explained by several existing hypotheses for HBsAg transmission.

Adolescent↗
PubMedDate not supplied

[Epidemiological surveillance of infection by the human immunodeficiency virus (HIV) and of the acquired immunodeficiency syndrome (AIDS) in French Polynesia in 1991].

The authors make out a statement about HIV infection in French Polynesia at the date of 1991 December 31. 96 cases all together of seropositive and AIDS infected people were recorded. These patients are young generally (78 p.c. between 21 and 40 years old) sexually contaminated (72 out of 96) and live in Tahiti island (94 p.c.). Sex-ratio is 2.8 male/1 female. Among them, we noted 55 p.c. of Europeans, 38 p.c. of Polynesians and 7 p.c. of Asiatic people. Epidemiological monitoring of the infection was made easy because of a set of laws and possibilities of detection highly favourable. Progress of the infection is constant, with 20 new cases detected each year with a prevalence of 150 cases of AIDS per 1 million of inhabitants, French Polynesia could be classified as the 5th or 6th region of France as far as the importance of the disease. Clinical, biological and epidemiological taking of charge of patients is detailed as well as the prevention campaign.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Epidemiologic aspects of malaria in Gabon].

The authors report the results of 3 sample surveys carried out in Libreville, Ngounié and Haut-Ogooué Provinces to evaluate the main malarial indexes among 0 to 15 years old children in Gabon. These investigations would suggest that malaria is mesoendemic in the three areas. The systematic presumptive antimarial treatment of fever attacks is widely used in Libreville but not so frequent in rural areas.

Adolescent↗