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Biomedical subjects

J Rodriguez

Publications and source records attributed to J Rodriguez.

At least 325 records · Page 18Linked to original sources
PubMed1969

Cell wall composition of the yeast and mycelial forms of Paracoccidioides brasiliensis.

Isolation and chemical analyses of the cell walls of the yeast (Y form) and mycelial forms (M form) of Paracoccidioides brasiliensis and Blastomyces dermatitidis revealed that their chemical composition is similar and depends on the form. Lipids, chitin, glucans, and proteins are the main constituents of the cell walls of both forms of these fungi. There is no significant difference in the amount of lipids (5 to 10%) and glucans (36 to 47%) contained by the two forms. In both fungi, the Y form has a larger amount of chitin (37 to 48%) than the M form (7 to 18%), whereas the M form has a larger amount of proteins (24 to 41%) than the Y form (7 to 14%). Several properties of the glucan of P. brasiliensis were studied. Almost all of the glucan in the Y form was soluble in 1 n NaOH, was weakly positive in the periodic acid-Schiff reaction, was not hydrolyzed by snail digestive juice, and had alpha-glycosidic linkage. Glucans of the M form were divided into alkali-soluble (60 to 65%) and alkali-insoluble (35 to 40%) types. The alkali-soluble glucan was similar to that of the Y form; the alkali-insoluble glucan was positive in the periodic acid-Schiff reaction and was hydrolyzed by snail digestive juice.

Amino Acids↗
PubMed1968

Mycelial phase of Paracoccidioides brasiliensis and Blastomyces dermatitidis: an electron microscope study.

A comparative study of the mycelial phase of Paracoccidioides brasiliensis and Blastomyces dermatitidis reveals that both fungi are very much alike, containing multiple nuclei and nuclear pores, mitochondria, ribosomes, scarce endoplasmic reticulum, intracytoplasmic membrane systems, glycogen, and vacuoles. Shadowed cell walls show fine fibrillar surfaces that contrast with those in the yeast phase. The intracytoplasmic membrane system is continuous with the plasma membrane and is similar to bacterial mesosomes. Granules with light cores and dark rims are observed in the plasma membrane. Live hyphae growing inside a dead hypha are found much more frequently in immersed cultures than in solid-medium cultures, suggesting that breakage of the hypha could elicit this phenomenon.

Blastomyces↗
PubMedDate not supplied

Risk factors for simultaneous carcinoma of the head and neck.

The upper aerodigestive tract is a preferential site for multiple primary cancer. The purpose of this study was to determine the characteristics of patients presenting with at least two simultaneous cancers of the upper aerodigestive tract compared with patients with a single location. Men patients (2,738) with squamous cell carcinoma were enrolled in the study. Of these, 120 (4.4%) presented with at least 2 simultaneous cancers (cancers detected within a 6-month period). The group of patients with simultaneous cancers was compared with a group presenting with a single location. Two factors (the mean daily alcohol consumption and employment as a "blue-collar" worker at any time during the working life) seem to be related to the occurrence of simultaneous cancers.

Aged↗
PubMedDate not supplied

Primary mediastinal large cell lymphoma.

PURPOSE: Primary mediastinal large cell lymphoma PMLCL is a recently described entity which has provoked considerable interest lately. The unique immunophenotype of the malignant cell, as well as conflicting reports regarding its response to therapy, prompted us to review the current literature focusing on the pathological and clinical aspects of this disease. DESIGN: We reviewed the current literature that contained details on the clinical presentation, pathological profile and clinical outcome. RESULTS: Most reports agree that PMLCL typically affects a young female population and presents with symptoms related to compression of mediastinal structures. Pathologically, the malignant cells may arise from a distinctive thymic medullary B cell subpopulation which is characterized by the following phenotype: CD19+, CD21-, CD20+, CD22+. Alterations of c-myc and lack of expression of HLA class 1 antigens on the tumour cell surface have been described. Response to treatment and clinical outcome have varied from one series to another and is possibly explained by the small number of patients in most series and by the heterogeneity of therapy. In general, the outcome does not appear to be worse than that of other large cell lymphomas although, given the young age of these patients, it might be expected to be more favourable. CONCLUSIONS: Primary mediastinal large cell lymphoma is a distinct clinico-pathological entity characterized by: (1) a predominance of young adults; (2) female predominance (female/male ratio of 2:1) in contrast to the other large cell lymphomas; (3) CD19+/CD21- immunophenotype; (4) absence of HLA-class 1 antigen expression; (5) possible involvement of c-myc; (6) frequent dissemination at relapse to unusual anatomic sites in a pattern reminiscent of Burkitt's lymphoma. The role of radiotherapy and the optimal treatment for this disorder are issues that remain unresolved.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Effect of zinc on the proliferative response of human lymphocytes: mechanism of its mitogenic action.

To study the effect of Zn on the proliferative response of normal human lymphocytes, ZnCl2 at a final concentration of 10(-4) M was added to cultures of peripheral blood mononuclear cells (PBMC) stimulated with concanavalin A (Con A) and to autologous mixed lymphocyte cultures of responder T lymphocytes and irradiated autologous non-T cells. Addition of Zn increased by about 50% the synthesis of DNA in cultures stimulated with either 10 or 20 micrograms/ml of Con A and markedly enhanced the autologous mixed lymphocyte reaction, which increased about 5-fold in the presence of Zn. In a narrow dose range, Zn induced per se the incorporation of [3H]thymidine by PBMC, with maximal effects in cultures stimulated with 10(-4) M ZnCl2. The percentage of cells expressing receptors for IL-2 and transferrin as assessed by immunofluorescence with the monoclonal antibodies (mAb) anti-Tac and OKT9, respectively, significantly increased when PBMC were stimulated with 10(-4) M ZnCl2 alone. Maximal [3H]thymidine incorporation and maximal percentage of cells bearing those activation markers were observed on day 6 of culture. Thus, the increase in the uptake of [3H]thymidine induced by Zn is not artifactual but due to progression in the cell cycle. Incubation with the mAb anti-Tac significantly inhibited the proliferative response to Zn, indicating that this requires binding of IL-2 to its receptor. However, addition of human recombinant IL-2 did not increase [3H]thymidine incorporation by PBMC cultured in the presence of ZnCl2.

Antibodies, Monoclonal↗
PubMedDate not supplied

Reproductive toxicity of Aroclor-1254: effects on oocyte, spermatozoa, in vitro fertilization, and embryo development in the mouse.

Polychlorinated biphenyls (PCBs) have been reported to adversely affect reproduction in laboratory and wild animals. The present study was undertaken to determine the toxic potential of Aroclor-1254 (A-1254) on in vitro fertilizing ability of oocytes and epididymal sperm and on preimplantation embryo development in the mouse. A-1254 was added to the IVF medium at concentrations of 0.01, 0.1, 1.0, and 10.0 micrograms/mL. Cumulus masses containing the oocytes were obtained from superovulated B6D2F1 mice and were placed in the culture medium containing A-1254 to which epididymal sperm, capacitated in a medium without A-1254, were added. The IVF rate was assessed 20 to 24 h after insemination. A-1254 significantly reduced the mean percent ova fertilized even at 0.1 microgram/mL. Incubation of the cumulus masses in various concentrations of A-1254 for 6 h, followed by insemination with sperm capacitated in the presence of A-1254, also significantly reduced the IVF rate. Capacitation of sperm in A-1254-containing medium, followed by coculture with untreated oocytes, failed to affect the IVF rate. No significant effect on sperm motility was observed following exposure to 1 and 10 micrograms/mL of A-1254. Estradiol-17 beta also reduced the IVF rate, however, the effect of A-1254 was more severe compared to the estradiol treatment. Furthermore, addition of A-1254 to the embryo culture medium was associated with a significant decrease in embryo growth at 48 h and 96 h. These results demonstrate adverse effects of A-1254 on oocytes, IVF, and embryonic development in the mouse.

Animals↗