Ricardo Negroni

Nuestra Experiencia de la Blastomicosis sudamericana en la Argentina

South American blastomycosis is a deep mycosis of the exogenous type of infection produced byParacoccidioides brasiliensis. It is endemic in wooded and humid zones of nearly all Latin American countries, being Brazil and Argentina the most deeply attacked. The incidence of clinical cases in Argentina has been reported in the following counties in order of decreasing importance: Chaco, Misiones, Corrientes, Santa Fé, Formosa, Santiago del Estero, Tucumán, Salta and Entre Rios. The incubation period may be as long as 40 years, and we agree withLacaz, MacKinnon andGonzález Ochoa on the possibility of the inhalatory type of infection. We propose the following clinical classification of the South American blastomycosis: I. Asymptomatic or subclinical S.A. blastomycosis (primary) II. Acute pulmonary S.A. blastomycosis III. Chronic pulmonary S.A. blastomycosis IV. Acute disseminated S.A. blastomycosis V. Chronic disseminated S.A. blastomycosis VI. Associated forms. Asymptomatic or subclinical S.A. blastomycosis (primary) Acute pulmonary S.A. blastomycosis Chronic pulmonary S.A. blastomycosis Acute disseminated S.A. blastomycosis Chronic disseminated S.A. blastomycosis Associated forms.

Ultrastructural changes produced by ketoconazole in the yeast-like phase of Paracoccidioides brasiliensis and Histoplasma capsulatum

AbstractThe ultrastructural changes produced by ketoconazole on the yeast-phase ofH. capsulatum andP. brasiliensis were studied by means of scanning and transmission electron microscopy.The observed alterations on both fungi were very similar to those induced by the same drug on the ultrastructure ofC. albicans. These alterations include surface changes, abnormal membrane proliferation, fatty degeneration of the cytoplasm and lysis of subcellular organelles. P. brasiliensis seems to be more sensitive to ketoconazole thanH. capsulatum, since the necrosis of most of the cells was obtained in the former at a concentration of 0.1 gmg/ml and in the latter at 1 μg/ml.

Rapid diagnosis of pulmonary mycosis by counterelectrophoresis.

Detection of precipitins in sera from pulmonary mycoses by the counterimmunoelectrophoresis technic is reported. This method is based on the application of a constant current of high potency on the Outcherlony technic with the result of a greater concentration of the reagents in the precipitation area and a greater speed of the reaction which can be read after one hour. We have registered positive results in all of 73 sera from patients mycologically proved of S. A. blastomycosis, coccidioidomycoses, histoplasmosis and aspergillosis. No cross reactions have been observed.

Inmunologia de las Candidiasis

Se presenta el estudio realizado en 70 casos de candidiasis con diversas localizaciones mediante pruebas de fijación de complemento, aglutinación, inmunodifusión e inmunoelectroforesis. Las pruebas de fijación de complemento e inmunodifusión presentaron títulos elevados sólo en aquellos enfermos que padecían candidiasis sistémicas, estas reacciones fueron sistemáticamente negativas en los casos de candidiasis superficiales. El anticuerpo específico presentó una movilidad electroforética semejante a la 1 g G. El antígeno más adecuado para las pruebas serológicas fue el sobrenadante de células deCandida albicans rotas en aparato Sorvall Ribi Cell fractionator. La prueba de aglutinación tiene menor valor pues se observaron escasas reacciones positivas en pacientes con candidiasis superficiales. La prueba cutánea fue positiva en la mayoría de los enfermos con candidiasis superficiales y broncopulmonares y, por el contrario, negativas en los casos examinados con septicemias y endocarditis. Sera from 70 patients with candidiasis have been studied by means of agglutination, complement fixation, agar gel immunodiffusion tests and immunoelectrophoresis technic. High titers in complement fixation and immunodiffusion tests have been registered in patients with systemic candidiasis, while the serologic study in those patients with superficialCandida infections gave negative results. Electrophoretic motility similar to that of 1 g G was observed in the specific antibody in candidiasis. Disrupted cells ofCandida albicans with Sorwall Ribi Cell fractionator gave the best antigens. Agglutination test seems to be of little diagnostic value. Positive skin test has been obtained in the majority of patients with superficial and bronchopulmonary candidiasis, while in those patients with septicemia and endocarditis negative results have been registered.

La inmunofluorescencia indirecta en el diagnostico serologico de las candidiasis sistemicas

The results of complement fixation tests and immunodiffusion agar gel tests in the serological studies of cases ofCandida septicaemia andCandida endocarditis were published in a previous paper. The results of the indirect immunofluorescence technic applied to the diagnosis of candidiasis are here reported. 51 positive results with titers ranging from 1/10 to 1/160 were obtained from sera of 100 persons without clinical manifestations of candidiasis. 33 positive results with titers ranging from 1/10 to 1/320 were registered from sera of 35 patients with superficialCandida infections. Sera from 10 patients withCandida septicaemia andCandida endocarditis gave strong positive reactions with titers ranging from 1/2.560 to 1/20.480. Positive results with fairly high titers were obtained in cases of bronchopulmonary candidiasis and in one case of candida endophthalmitis. Estudiamos la presencia de anticuerpos contraCandida albicans, mediante la técnica de inmunofluorescencia indirecta, este trabajo pretende completar un estudio anterior, presentado por uno de nosotros, en el que demostramos el valor de las pruebas de fijación de complemento e inmunodifusión en gel de agar para el diagnóstico de las septicemias y endocarditis moniliásicas. El antígeno empleado fué una suspension de células deCandida albicans cepa 3043 del Centro de Micología. La antiglobulina humana unida a isotiocianato de fluoresceina provenía del Instituto Pasteur de París. Se estudiaron los sueros de 100 dadores de un banco de sangre, 51 dieron reacciones positivas y 49 negativas, los títulos de los sueros positivos fueron: 1/10 22 sueros, 1/20 13, 1/40 8, 1/80 4, y 1/160 3. Se examinaron 35 sueros de pacientes portadores de candidiasis superficiales, de los cuales 33 fueron positivos con títulos que variaron de 1/10 a 1/320. Estudiamos los sueros de 10 pacientes que padecían septicemias y endocarditis porCandida con hemocultivos positivos, todos dieren reacciones fuertemente positivas con títulos que oscilaron entre 1/2560 y 1/20480. La prueba de inmunofluorescencia indirecta fué igualmente positiva, con títulos moderadamente elevados en dos pacientes portadores de moniliasis broncopulmonar y en uno con una endoftalmitis porCandida.

Antígenos del paracoccidioides brasiliensis para las Reacciones serológicas

The sera from normal subjects gave negative results with the following antigens used in the complement-fixation tests: 1) polysaccharide prepared according toFava Nettos technic; 2) a filtrate of shaked cultures followingAjello et al.s technic; 3) an aqueous extract of mechanically disrupted yeast cells ofP. brasiliensis. The sera from patients of S.A. blastomycosis gave positive c.f. tests with the three antigens with titer ranging from 1/20 to 1/5, 160. Antigen No 2 gave in 11/18 cases higher titers than the other antigens. Immunodiffusion tests gave positive results with the antigen no 2. The sera from 10 cases of histoplasmosis gave cross reactions with the antigen No 3, in 5/10 cases with the antigen No 2 and in not any case with the antigen No 1.

Studies on Coccidioides immitis. XVII: Morphology of the parasite in relationship with the host immunoallergic condition in the experimental infection of the guinea-pig.

Male guinea-pigs were inoculated by the testicular route with a suspension of chlamydo-arthrospores of the filamentous phase ofC. immitis. The following histopathological changes were observed: voluminous pyocytic foci as well as granulomatous mononuclear reaction was initially observed and granuloma with multinucleated giant cells were seen 20 days after the inoculation. The following changes of the microscopic aspect of the parasite were correlatively registered: the so-called primary infection type of sporangia appear in great number three days after the inoculation. This type of sporangium is characterized by its great diameter up to 98 µ, peripheral endospore formation leaving a large central vacuole which frequently contain residual protoplasm. The endospores are thin walled, polyhedral and get free through an ostiole. Sporangia completely filled with globose endospores (the cystic type of sporangia) with radiate acidophilic formations on the peridial wall were observed in the testicles of the guinea-pigs killed 6 days after the inoculation. Reduction in number and in the size of the parasite were seen after the 20th. day of the inoculation. Radiate formation of the cell wall of the parasite appeared simultaneously with precipitin antibodies and would be the expression of antigen-antibody reaction. All the intermediate types of sporangia between the primary infection type and the cystic type were observed after the 10th. day of the inoculation.