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Biomedical subjects

R Parra

Publications and source records attributed to R Parra.

34 records · Page 2Linked to original sources
PubMed1990

Induction of Hydrolytic Enzymes in Brassica campestris in Response to Pathovars of Xanthomonas campestris.

Inoculation of mature leaves of turnip (Brassica campestris) with the incompatible Xanthomonas campestris pv vitians resulted in the induction of beta-1,3-glucanase and chitinase/lysozyme (CHL) activity. No increase in the basal activity of beta-1,3-glucanase was observed after inoculation of leaves with heat- or rifampicin-killed X. c. vitians, Escherichia coli, or sterile water. Inoculation with the compatible X. campestris pv campestris resulted in a slower induction of glucanase than that seen with X. c. vitians. In contrast, all bacteria caused an induction of CHL activity. One major beta-1,3-glucanase (molecular mass 36.5 kilodaltons, isoelectric point [pl] ~8.5) was purified from both inoculated and untreated leaves by ion-exchange chromatography. The enzyme degraded laminarin by an endo-glycolytic mechanism. Two major CHL isozymes (CHL 1 and CHL 2, molecular mass 30 kilodaltons and pl 9.4 and 10.2, respectively) were purified from X. c. vitians inoculated leaves by affinity chromatography on a chitin column followed by ion-exchange chromatography. Both enzymes degraded chitin by an endo-glycolytic mechanism although the ratio of lysozyme to chitinase specific activities for CHL 1 and CHL2 were different. The induction of CHL 1 was associated with the hypersensitive reaction caused by X. c. vitians whereas all other treatments induced largely CHL 2.

Journal Article↗
PubMed1990

[Posttransfusion thrombocytopenic purpura. 1st case described in Spain].

Following a total blood transfusion, a 65 year old woman suffered severe thrombocytopenia characterized by purpura and haemorrhage. An immunological study revealed the existence of IgG and IgM type antibodies in the serum attached to the patient's platelets and to the eluate obtained from these. The specificity of the antibody was Zwa. The patient's platelets are Zwa-negative. Even in the remission phase of the thrombocytopenia it was still possible to obtain antibodies in the platelets of the eluate. Questions raised by this factor are discussed and, despite the difficulties posed, an attempt is made to find a coherent immunological explanation based on the results of the serological study.

Aged↗
PubMed1986

Survival after intestinal mucormycosis in acute myelogenous leukemia.

A young woman with acute myelocytic leukemia developed acute lower gastrointestinal bleeding immediately after a first remission induction of her leukemia. After the site of bleeding was located in the descending colon, a necrotic bleeding ulcer was resected. Histologic examination of the ulcer established the diagnosis of gastrointestinal mucormycosis. Treatment with amphotericin B was administered because of the high risk of dissemination. The patient has been followed for 9 months with no evidence of relapse of infection. Survival after gastrointestinal mucormycosis in acute leukemia has not previously been reported in the English language literature. Success in managing mucormycosis depends on the adherence to the recommended principles of early aggressive diagnostic measures, excisional surgery, amphotericin B therapy, and control of the underlying predisposing condition.

Adult↗
PubMed1986

Relations between nucleolar morphometric parameters and pre-rRNA synthesis in animal and plant cells.

In order to study if there are differences between cells of the same tissue with one and two nucleoli, nuclear and nucleolar volume, density of tritiated uridine incorporation, amount of DNA per nucleus and intensity of cytoplasmic basophilia were measured in mononucleolated and binucleolated rat epithelial endometrial cells, in onion root meristematic cells and in chick embryo matrix cells of the central nervous system, neuroblasts and neurons. No significant differences in nuclear volume, density of tritiated uridine incorporation and amount of DNA per nucleus were found between cells of the same type with diverse numbers of nucleoli. Binucleolated endometrial cells, matrix cells, and root meristematic cells have biphasic distributions of nucleolar volumes. One peak of this distribution roughly coincides with the nucleolar volume of mononucleolated cells, the other peak corresponds almost to double the volume. As the density of uridine incorporation is the same irrespective of the nucleolar number and volume, the cells with larger nucleolar volumes have higher pre-rRNA synthesis. These cells also have higher amounts of ribosomes in the cytoplasm, as revealed by the photometric study of basophilia. It is concluded that in this population of cells the ribosomal production is regulated to a higher steady equilibrium than in the general population. This difference is not due to polyploidism or to the increased DNA content of G2 phase cells. Binucleolated neuroblasts and neurons have nucleolar volumes similar to those of mononucleolated ones.

Animals↗
PubMed1985

Effects of progesterone on nuclear ribonucleoprotein constituents of endometrial cells of the rat.

The effects of changes of progesterone concentration on 3H-uridine incorporation and on the volume or number of nuclear ribonucleoprotein particles of the rat endometrial epithelial cells are studied in vivo and in vitro. All progesterone treatments are carried out after estradiol priming and their results are compared with estradiol-treated controls sampled from the same uterus or the same pool of isolated cells. Progesterone induces the same changes, in the parameters studied, administered in vivo or in vitro. Nuclear volume undergoes small but significant increases between 1/2 and 8 h of treatment. The total number of extranucleolar ribonucleoprotein structures as well as the incorporation of 3H-uridine on non-nucleolar areas are also increased by progesterone treatments. However, the numerical density of perichromatin granules does not change during these experiments. The nucleolar volume and the incorporation of 3H-uridine in this structure are increased after an early diminution. These results indicate that progesterone induces small increases in the rate of transcription in the nucleolus and in non-nucleolar genes. The constancy of the density of perichromatin granules suggests that progesterone, in contrast to estradiol, does not affect the ratio transcription/transportation of RNA to the cytoplasm.

Animals↗
PubMedDate not supplied

[Renal actinomycosis: presentation of a case].

Renal actinomycosis is rarely suspected and is difficult to diagnose, limited to a few cases in any series. A 56-year-old man with renal actinomycosis and Rendu-Osler disease is described. Long-term therapy with penicillin resulted in a clinical cures. A case report is presented.

Abscess↗