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R Flores

Publications and source records attributed to R Flores.

At least 127 records · Page 7Linked to original sources
PubMed1984

Glucocorticoid inhibition of zymosan-induced arachidonic acid release by rat alveolar macrophages.

The phospholipase-dependent liberation of arachidonic acid (AA) from membrane phospholipids has been proposed as the rate-limiting step in the synthesis of bioactive AA metabolites, which play an important role in the expression of inflammatory and immune reactions. We have examined the effects of steroids in vitro on the release of AA by rat alveolar macrophages exposed to zymosan. Fluocinolone (1 microM) significantly inhibited the zymosan-induced release of radiolabeled AA from phosphatidylcholine as well as the production of radiolabeled prostaglandin E2. (PGE2). Dose-response curves gave the following rank order of potency: fluocinolone greater than dexamethasone greater than hydrocortisone. The maximal degree of inhibition of radiolabeled AA release observed was approximately 70%. Inhibition was not observed after 3 h of glucocorticoid pretreatment, but maximal inhibition was achieved after 10 h of pretreatment. Pretreatment with gonadal sex hormones (1 microM) did not inhibit AA release. Concurrent incubation of macrophages with hydrocortisone and excess concentrations of the partial glucocorticoid agonist, progesterone, blunted the degree of inhibition observed with hydrocortisone alone. These data are consistent with a receptor-mediated process. The time course suggests a response dependent on new protein synthesis, and the increased concentration of the phospholipase-inhibitory protein, lipomodulin, in steroid-treated cultures is putative evidence of new protein synthesis.

Animals↗
PubMed1983

Fractionation with ethanol of nucleic acids from viroid-infected plants.

A combination of high salt and low ethanol concentration allowed the fractionation of nucleic acids extracted from viroid-infected leaves. By adding 0.4-0.5 vol of ethanol to 1 vol of a solution in 2 M LiCl of nucleic acids (containing mainly DNA, 4S, 5S, 7S, and viroid RNAs), 85% of the DNA and 75% of the 4S RNA remained in solution, from where they could be recovered by increasing the ethanol concentration, whereas almost all 5S, 7S, and viroid RNAs precipitated. When this process was repeated three times a 95% elimination of the initial DNA and 4S RNA was achieved. The method can be of special interest in viroid purification considering that DNA and 4S RNA are the most abundant contaminants in the starting solution of nucleic acids. It is suggested that the highly ordered secondary structure of viroid RNA may be responsible for its particular behavior in the ethanol fractionation of nucleic acids.

DNA↗
PubMed1983

Brucella spp. from the capybara (Hydrochaeris hydrochaeris) in Venezuela: serologic studies and metabolic characterization of isolates.

A bacteriological and serological study of 201 wild capybara from the llanos, State of Apure, Venezuela was made to isolate Brucella from spleen and lymph node tissues and determine the role of this rodent as a reservoir of this bacteria. Twenty-three isolations were made, eight were identified as B. abortus and 15 as B. suis by oxidative metabolic techniques. A Poly B antigen in immunodiffusion in gel test was compared with other serologic tests. There was good correlation and 58% of sera were positive. The age and sex distribution of animals from which isolations were made and serological reactors indicated that this species may be an important alternate host of Brucella spp. in Venezuela.

Age Factors↗
PubMed1983

[Basic procedures in data registers and processing].

This paper describes the general principles that must be used as a frame of reference to identify the appropriate procedures for the management of data collected in large scale studies. It has two parts: 1) Data recording and, 2) data processing. In the first part (data recording), the various steps required for the preparation of forms and/or questionnaires and for the recollection of data are discussed. In the second part (data processing), the steps to achieve real quality control, proper coding and data entry for analysis are described. For the latter case, an outline of continuous general steps is proposed, and some statistical procedures commonly used for testing different hypotheses are identified. The overall process is illustrated through flow charts, emphasizing the fact that the processing and analysis of data, must be a continuous action which requires careful definition in the standard protocol of operations.

Data Collection↗
PubMed1982

Properties of a cell-free system for synthesis of citrus exocortis viroid.

Partially purified nuclei from citrus exocortis viroid (CEV)-infected Gynura aurantiaca are able to synthesize linear and circular viroid molecules. Pretreatment of the nuclei with actinomycin D or deoxyribonuclease did not affect viroid synthesis, whereas the synthesis of other cellular RNAs was severely reduced. These observations support the essential role of CEV complementary RNA sequences in viroid replication. However, when alpha-amanitin was included in this in vitro synthesis system, CEV replication was markedly reduced by concentrations of 10 nM or greater. Taken together, these data support the proposition that viroid synthesis is catalyzed by a DNA-dependent RNA polymerase acting on a RNA template.

Journal Article↗
PubMed1981

Deliberations on the problems of mammomonogamus species (Nematoda, Syngamidae) in ruminants.

The taxonomy of mammomonogamids parasitic in ruminants is discussed with regard to their different rates of variability in Cuba and Mexico. Since their variability is large and the existence of biological species is not based on their morphology but on the reproduction isolation of populations, the authors came to the conclusion that the specific analysis of mammomonogamids will be convincing only in case that it is carried out using taxonomic experiments of special orientation.

Animals↗
PubMed1980

Scanning electron microscopic study of Mammomonogamus laryngeus.

Surface structures, particularly numerous body sculptures of the nematode M. laryngeus recovered from cattle in Cuba were studied by scanning electron microscopy. New morphological structures in form of "granulations" were found of the mouth capsule. The structure of cuticle in region of vulva opening and of bursa cuticle was described in detail. It was found that even older preserved material of helminths can be used for SEM studies.

Animals↗
PubMedDate not supplied

System care improves trauma outcome: patient care errors dominate reduced preventable death rate.

UNLABELLED: A review of 452 trauma deaths in Hillsborough County, Florida, in 1984 documented that 23% of non-CNS trauma deaths were preventable and occurred because of inadequate resuscitation or delay in proper surgical care. In late 1988 Hillsborough County organized a County Trauma Agency (HCTA) to coordinate trauma care among prehospital providers and state-designated trauma centers. The purpose of this study was to review county trauma deaths after the inception of the HCTA to determine the frequency of preventable deaths. RESULTS: 504 trauma deaths occurring between October 1989 and April 1991 were reviewed. Through committee review, 10 deaths were deemed preventable; 2 occurred outside the trauma system. Of the 10 deaths, 5 preventable deaths occurred late in severely injured patients. CONCLUSION: The preventable death rate has decreased to 7.0% with system care. The causes of preventable deaths have changed from delayed or inadequate intervention to postoperative care errors.

Adolescent↗
PubMedDate not supplied

Some properties of the viroid inducing peach latent mosaic disease.

Analysis by polyacrylamide gel electrophoresis of nucleic acid extracts from different peach samples, healthy or infected with the peach latent mosaic (PLM) disease, demonstrated the association of this disease with an RNA exhibiting the electrophoretic properties typical of circular viroid molecules. This RNA was called peach latent mosaic viroid (PLMV), since a purified preparation of it, when inoculated into GF 305 peach seedlings induced characteristic symptoms of PLM disease. PLMV was estimated to have a molecular size in the range of 330-340 bases, by comparison of its electrophoretic mobility under denaturing conditions with those of several viroid RNA. Dot-blot analysis showed that PLMV had a sequence clearly different from other viroids, including citrus exocortis viroid, apple scar skin viroid (ASSV), hop stunt viroid (HSV) and avocado sunblotch viroid. The possible significance of the limited sequence homology shared by PLMV with HSV, and especially with ASSV, is discussed.

Fruit↗