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C Rivas

Publications and source records attributed to C Rivas.

154 records · Page 9Linked to original sources
PubMedDate not supplied

Lennert's lymphoma with giant multivesicular lysosomal bodies optically visible.

A case of a 43-year-old male patient with lymphoepithelioid lymphoma is discussed. During the 10-year follow-up of this patient, different biopsy specimens were obtained. Immunohistochemical studies with a complete paraffin panel determined a T-cell nature of the specimens. Electron microscopy showed a peculiar finding in the cytoplasms of the tumoral cells that correlated with optical inclusions observed in optical imprints; these imprints corresponded to lysosomic multivesicular bodies, whose significance is discussed.

Adult↗
PubMedDate not supplied

[In vitro sensitivity of Paracoccidioides brasiliensis to systemically used antifungal agents].

In 1992, the NCCLS proposed a broth macrodilution method for determining the in vitro susceptibility of yeast. However, for dimorphic fungi no standardised method is available. The aim of our study was to evaluate the reference broth macrodilution method with isolates of Paracoccidioides brasiliensis. The in vitro susceptibility of two ATCC strains (32069 and 36324) and nine clinical isolates were determined against serial dilutions of amphotericin B (AMB), ketoconazole (KTZ), and itraconazole (ITZ) from 0.02 to 20 mg/l and fluconazole (FCZ) from 0.1 to 100 mg/l. The inoculum used was 0.5 x 10(4)-2.5 x 10(5) CFU/ml, employing the yeast phase in order to obtain homogeneous growth. The test was incubated with agitation in a rotating shaker at 35 degrees C, and 7 days was the optimal time for MIC final reading. Average MIC50/MIC90 (mg/l) for the eleven isolates tested were the following: AMB: < 0.02/0.16, FCZ: 1.6/6.2, KTZ: 0.08/0.31, ITZ: 0.31/1.3. One clinical isolate showed high MIC for azole drugs (KTZ: 1.3 mg/ml, FCZ: 100 mg/l and ITZ 5 mg/l). Although further studies are necessary to evaluate the usefulness of this methodology for P. brasiliensis, the latter may be clinically useful to predict the development of resistance.

Amphotericin B↗
PubMedDate not supplied

[Malassezia species isolated from skin diseases in a care center in the city of Buenos Aires, Argentina].

The epidemiology of Malassezia genus is poorly understood; geographical and population factors might have influence on the species distribution. The aim of this work was to determine the frequency of Malassezia species involved in skin diseases in a diagnostic center at Buenos Aires City. From 02/01/1999 to 10/31/2001, 456 skin specimens from 447 patients diagnosed as pityriasis versicolor, seborrheic dermatitis, foliculitis and atopic dermatitis, were analyzed by microscopic examination and culture. Malassezia spp was evidenced in 255 skin samples (55.9%) by microscopic analysis but it could be recovered from only 99 (38.8%) specimens. Malassezia species were isolated from 10 (3.9%) scarring lesions that were negative by microscopy. Among 109 isolates, M. sympodialis (58.7%) was the most frequent, followed by M. globosa and M. furfur (18.3% and 9.2%). Unique isolates (0.9%) of M. obtusa, M. slooffiae and M. restricta were recovered. Eleven isolates (10.1%) could not be identified because they had lost viability in the culture. This is the first study on Malassezia species associated to skin diseases in Argentina; further screening including other geographic regions of the country is necessary in order to confirm these results.

Adolescent↗
PubMedDate not supplied

Comparative molecular study of Mycobacterium tuberculosis strains, in times of antimicrobial drug resistance.

Strains of Mycobacterium tuberculosis were compared using two DNA fingerprinting techniques: Restriction Fragment Length Polymorphism (RFLP) and Double-Repetitive-Element-PCR (DRE-PCR). Two of these strains: IH1 (susceptible to isoniazid) and IH2 (resistant to isoniazid) were recovered from cases of pulmonary tuberculosis which occurred in two brothers who lived together. The first one was recognized on July 1999, and the second was diagnosed one year later. IH1 and IH2 showed the same pattern of bands with both molecular tests. These results suggest that single drug chemoprophylaxis may occasionally select resistant strains for that drug, which can eventually cause disease and be recognized through these tests. Strains IH3, IH4 and IH5 were obtained from sputum samples of 3 different patients, and intra-laboratory cross-contamination was suspected when it was realized that the 3 positive materials had been consecutively processed the same day by the same worker in the same biological safety cabinet. Again, the 3 strains revealed identical band patterns with RFLP and DRE-PCR, confirming the posed suspicion. The results with DRE-PCR were obtained after only 8 hours of work, without the need for subcultures. This procedure allows quick correction of treatment conducts, avoiding unnecessary exposure of people and bacteria to antimicrobial drugs.

Adult↗
PubMedDate not supplied

[Disseminated mycobacterial infections in patients with HIV/AIDS. Evaluation of blood cultures].

One thousand-forty blood cultures corresponding to 451 Uruguayan patients with AIDS and clinic diagnosis of disseminated mycobacterial infection were evaluated between 1999 and 2003. Samples were processed in the National Reference Center for Mycobacteria (Montevideo, Uruguay), using the automated blood culture system for mycobacteria MB-BacT (BioMérieux). Forty-five positive samples were detected (4.3%) corresponding to 26 patients with AIDS (average 2.3 samples per patient). In 10/26 patients M. avium complex (MAC) was identified and in 13/26 the isolated germ was M. tuberculosis. The average time of incubation was of 12.4 days (range 6-19 days) for MAC and of 22.6 days (range 7-35 days) for M. tuberculosis. Blood culture has demonstrated to be the best sample for the bacteriological confirmation of the disseminated mycobacterial infections when at least 2 samples by patient are studied. The frequency of isolates of M. tuberculosis and MAC in AIDS patients is according with a moderate prevalence of tuberculosis in Uruguay.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

[Radical surgery of locally advanced prostatic cancer].

Retrospective study in 51 patient with locally advanced prostate cancer (34 pT3 and 17 N+) selected from 88 radical prostatectomies performed between February 1985 and December 1993. An evaluation is made of the clinical/pathological stage correlation and the effectiveness of the different diagnostic methods (61% of understaging). The possibility to rescue locally spread tumours is analyzed, 7/51 (13.72%) patients receiving pre-operative neoadjuvant hormonal therapy. Estimated survival at 8 years was 82.6% of all patients treated with radical surgery and, at the end of the study, the situation of 30/46 (65.2%) patients assessed by digital rectal examination, quality of life index, PSA follow-up, abdominal ultrasound and/or CT, bone scan and chest X-ray, was an estimated 8-year disease-free evolution. It is observed that radical surgery and the post-surgical hormonal approach permit good survival in locally advanced prostate cancer and that the use of a neoadjuvant hormonal approach permit good survival in locally advanced prostate cancer and that the use of a neoadjuvant hormonal approach allows in many cases the rescue of patients for radical surgery.

Aged↗
PubMedDate not supplied

[Specific fungal antisera production in rabbits].

A method for fungic antisera production against Aspergillus fumigatus, Histoplasma capsulatum, Paracoccidioides brasiliensis and Coccidioides immitis in rabbits was evaluated. Intradermic via and antigen in the dilution used for routine tests (UD) were employed to produce positive control serum for immunodiffusion test in agar gel. A. fumigatus, H. capsulatum and C. immitis antigens were prepared as described in CDC's Procedure Manual, P. brasiliensis antigen was prepared as previously described by Pires de Camargo. All rabbits produced antibodies against the different specific antigens in the primary response peak and after each booster. The titer obtained in secondary response was similar or smaller than the primary response in all cases. However, bands of similar quality and intensity were obtained by immunoprecipitation in agar gel tests. Although the antibody titers proved to be similar, higher or lower concentration of antigen used in the primary immunization produced fewer and smeared bands, respectively. This effect was evaluated in A. fumigatus only. Specific antisera production with this method proved to be easy and yielded high quality antisera. The major advantages of this method are: a) reduced number of inoculations, b) fast and simple standardisation of the antigen needed, c) equally useful for all the fungal species used so far. Therefore we strongly recommend this method.

Animals↗