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Biomedical subjects

P Brasseur

Publications and source records attributed to P Brasseur.

At least 73 records · Page 4Linked to original sources

Respiratory tract cryptosporidiosis in immunosuppressed rat is associated with an epithelial metaplasia.

Cryptosporidium parvum is an opportunistic protozoa that chronically infects the digestive tract of immunocompromised hosts. Respiratory cryptosporidiosis, which was reported in AIDS patients, is an uncommon feature of mammalian cryptosporidiosis models. In this study, we document the respiratory lesion; observed in an immunosuppressed rat model of cryptosporidiosis. Twenty rats were immunosuppressed with corticosteroids and low protein diet. They were challenged intratracheally with 10(6) C. parvum sporozoites. Lungs and ileums were examined on D3, D6, D10, D14. On D10 and D14, C. parvum were present in the respiratory tract of all animals in association with the progressive appearance of an immature malpighian metaplasia. On D14, an intestinal infection was also detected in 2/4 animals. The respiratory tract appears to be a fully permissive area for the protozoa in immunosuppressed rats. Introduction of parasites on the respiratory mucosa seems a requisite to induce respiratory cryptosporidiosis. This experimental protocol yields a low mortality rate, and so modelizes late and/or chronic stages of respiratory cryptosporidiosis.

Animals↗

[Sensitivity in vivo and in vitro of Plasmodium falciparum to chloroquine and amodiaquine in Bangangte (west Cameroon)].

A cross-sectional malaria survey was conducted during the rainy season in Bangangté (West-Cameroon), a town of 90,000 inhabitants located in the high tablelands zone of Cameroon. An in vivo study revealed that 50% of P. falciparum malaria patients were resistant to chloroquine (25 mg/kg over 3 days) and 26.3% to amodiaquine (35 mg/kg over 3 days) at a RII/RIII level. In addition, plasmodial indices indicated that malaria was mesoendemic in this area of Cameroon.

Adolescent↗

Successful treatment of Acanthamoeba keratitis by hexamidine.

Acanthamoeba keratitis remains very difficult to treat because of the lack of antiamoebic agents completely effective against cysts. Currently, the recommended treatment includes the use of topical neomycin sulfate, various imidazoles, and propamidine isethionate (Brolene) 0.1% eye drops, a compound of the diamidine family. In the present article, we describe the successful management of two patients with an Acanthamoeba keratitis, treated with hexamidine diisethionate (Desomedine) 0.1% eye drops, another diamidine derivative, which was found amoebicidal in vitro on the isolated Acanthamoeba strains. This is to our knowledge the first report on the amoebicidal effectiveness of hexamidine, simultaneously in vitro and in vivo.

Acanthamoeba↗

Human TcR gamma delta+ lymphocyte response on primary exposure to Plasmodium falciparum.

In 29 patients experiencing their first P. falciparum malarial attack, blood levels of TcR gamma delta+ lymphocytes were studied from the onset of infection to up to 6-9 months later. Blood TcR gamma delta+ lymphocytes, revealed using the TcR delta 1 monoclonal antibody (MoAb), were increased both in absolute and relative numbers. Alterations lasted for up to 3-4 months following the attack. A Ti gamma A/BB3 reactive V gamma 9 subset was preferentially amplified. In vitro, TcR gamma delta+ lymphocytes from both malaria-sensitized and unprimed donors responded to P. falciparum schizont extract (PFSE). PFSE-stimulated polyclonal T cell lines consisted principally in TcR gamma delta+ cells with a Ti gamma A+/BB3+ phenotype. Several TcR gamma delta+ T cell clones obtained from patients recovering from acute malarial attack were maintained in the presence of PFSE and autologous irradiated PBL. They belong to the V gamma 9 subset. In long-term cultures, TcR gamma delta+ clones progressively lost their capacity to react to PFSE antigen while they were able to proliferate and to exert cytotoxic activity in response to autologous TcR alpha beta+, PFSE-specific T lymphocyte clones. This suggests that regulatory interactions occur between activated TcR gamma delta+ and TcR alpha beta+ cells generated by P. falciparum. Sequential variations in blood TcR gamma delta+ and TcR alpha beta+ lymphocyte levels after primary exposure to P. falciparum suggest that such regulatory interactions may occur in vivo.

Acute Disease↗

Pineal body metastasis.

We present a rare case of a pineal body metastasis developed from an oat cell carcinoma of the lung. Diagnosis by CT brain scan was easy but could have been difficult if the metastasis was solitary with the primary focus of tumor unknown. This lesion was temporarily radiosensitive but non-responsive to cytotoxic drugs and the patient died after other metastases developed.

Brain Neoplasms↗

An immunosuppressed rat model for evaluation of anti-Cryptosporidium activity of sinefungin.

Cryptosporidium parvum causes life-threatening diarrhoea in immunocompromised, especially AIDS patients and the efficiency of proposed anti-cryptosporidial therapies is limited or doubtful. An immunosuppressed adult rat model of C. parvum infection was developed for screening molecules candidate for curative and preventive activity in human cryptosporidiosis. Among 31 drugs tested, lasalocid (2-10 mg/kg/24 h), and sinefungin (2-10 mg/kg/24 h), exhibited some activity against C. parvum infection. Oral sinefungin therapy resulted in a dose related suppression of oocysts shedding, which correlated with oocyst disappearance from ileum sections and was also efficient in preventing infection. Relapses were observed after discontinuation of curative sinefungin therapy, which suggests that the biliary tract, a major location and parasite reservoir which sustains persisting infection, was not cleared of parasites by the drug. Improved therapeutic procedures with sinefungin (or analogues) will result from current pharmacological studies.

Adenosine↗

Assessment of candidate anticryptosporidial agents in an immunosuppressed rat model.

Cryptosporidium parvum causes life-threatening diarrhea in immunocompromised patients, especially those with AIDS. The efficiency of currently proposed anticryptosporidial therapies is limited or doubtful. In this report, molecular candidates for curative or preventive activity were investigated in an immunocompromised rat model that mimics severe human cryptosporidiosis. No significant anticryptosporidial activity was observed when using sulfadoxine-pyrimethamine, quinacrine, trimethoprim-sulfamethoxazole, bleomycin, elliptinium, daunorubicin, pentamidine, alpha-difluoro-methylornithine, diclazuril or N-methylglucamine. Vitamin A appeared to reduce oocyst shedding. Active agents included sinefungin (2-10 mg/kg/24 h), lasalocid A (2-10 mg/kg/24 h), metronidazole (25-50 mg/kg/24 h), and sulfadimethoxine (10-100 mg/kg/24 h). Sinefungin (10 mg/kg/24 h) and lasalocid A (10 mg/kg/24 h) displayed the highest anticryptosporidial activity.

Animals↗

Curative and preventive anticryptosporidium activities of sinefungin in an immunosuppressed adult rat model.

An immunosuppressed rat model was used to investigate the anti-Cryptosporidium parvum activity of sinefungin. In infected animals, oral sinefungin therapy resulted in a dose-related suppression of oocyst shedding, which correlated with oocyst disappearance from ileal sections. When administered prior to or on the day of oocyst challenge, sinefungin successfully prevented infection. These data suggest that sinefungin could be considered as a candidate molecule in the treatment of human cryptosporidiosis, considered to be the most significant enteric opportunistic infection in AIDS.

Adenosine↗

[In vivo resistance of Plasmodium falciparum to chloroquine in Anjouan (Comoros)].

An in vivo study of P. falciparum sensitivity to chloroquine was conducted at Anjouan island (République fédérale islamique des Comores) from December 1990 to March 1991. The 27 patients included in the study were given chloroquine at a dose regimen of 25 mg/kg over 3 days and were followed up 7 days. Six patients (22.2%) still harboured parasites up to day 7, thus showing a RII/RIII level of resistance. This is likely related to an increased chloroquine consumption by the inhabitants of this island since 1987.

Adolescent↗

Human babesiosis in Europe.

Human babesiosis in Europe came to medical attention in 1957 and until now 19 cases have been reported, most of them due to Babesia divergens. The onset of the disease is characterized by hemoglobinuria, high fever and renal failure ensue rapidly. The patients were generally asplenic and resident in a rural area. Intraerythrocytic pleomorphic parasites (1-3 microns) observed in stained thin blood smears are essential for Genus diagnosis. Parasitemia varied from 5 to 80% of red blood cells. Massive blood exchange transfusion (2-3 blood volumes) followed by intravenous clindamycin (3-4 times daily) and oral quinine (600 mg base, 3 times daily) were successfully used in the treatment of three recent cases. Splenectomised individuals should be aware for prevention.

Acute Kidney Injury↗

Mefloquine resistant malaria in Cameroon and correlation with resistance to quinine.

Based on the results of in vitro sensitivity of Plasmodium falciparum to chloroquine, quinine and mefloquine, and evaluation of drug consumption conducted in 1987-1988 in four areas in the north and south-west of Cameroon, two opposite situations were encountered in this country. In northern Cameroon where mefloquine resistance is prevalent a close correlation was found between the responses of P. falciparum to mefloquine and to quinine, but not between mefloquine and chloroquine. In the south, where chloroquine resistance is highly prevalent, no correlation was found neither between mefloquine and chloroquine nor mefloquine and quinine, but the responses to quinine and chloroquine appear partly correlated. These results lead to formulate the hypothesis of a "southern" type of P. falciparum submitted to a high chloroquine drug pressure inducing a secondary cross resistance, whilst a "northern" type submitted to a relatively high and abortive quinine drug pressure inducing a primary quinine resistance and a secondary cross resistance with mefloquine.

Animals↗