PubMed Health⌕ Search

Biomedical subjects

R Rodríguez

Publications and source records attributed to R Rodríguez.

At least 163 records · Page 9Linked to original sources
PubMed1996

[ELISA identification of agents causing light cytopathic effect isolated during the neuropathy outbreak in Cuba, 1991].

Using as a reference the strain 44/93 isolated during the neuropathy epidemic in 1991 and characterized as a producer of a light cytopathic effect (L-CPE), it was possible the standardization of an ELISA for the fast identification of other strains with similar effect. The assay consisted in a sandwich-type ELISA where the conditions selected for each reactive (10 micrograms/mL for the coating antibody, 1 mg/mL for the antigen, and dilution 1/2,000 for the conjugate) allowed to have an adequate discrimination between the antigen and the antigen control for the reference strain used. The evaluation of a panel of reference viral strains and of other L-CPE producing strains showed a 100% of coincidence between this method and the isolation in cellular culture. The results obtained permit us to recommend the use of this assay as a more precise alternative to identify these agents.

Cuba↗
PubMed1995

Concanavalin A- and wheat germ agglutinin-conjugated lectins as a tool for the identification of multiple N-glycosylation sites in heterologous protein expressed in yeast.

We report here a methodology that allows the identification of glycosylation sites by a combination of protein enzymatic digestion, glycopeptide separation on a reverse-phase HPLC column, and further recognition in a dot-blot system using concanavalin A-horseradish peroxidase. Wheat germ agglutinin-horseradish peroxidase is used as the recognition system for peptides generated after proteolytic digestion of endoglycosidase H deglycosylated protein. Glycosylation sites were confirmed by automatic Edman degradation and fast atom bombardment mass spectrometry. This methodology was applied to a model glycoprotein, alpha-amylase from Bacillus licheniformis, which is unglycosylated in its natural host and appears highly glycosylated when expressed in the methylotrophic yeast Pichia pastoris.

Amino Acid Sequence↗
PubMed1995

Flagelliform or coronata glands of Nephila clavipes.

The flagelliform or coronata glands of the orb-web spider, Nephila clavipes, have been studied and compared to other silk-producing glands from the organism. The glands, which produce silk for the double filament of the core thread in the sticky spiral, exhibit three distinct morphological areas: tail, sac, and duct. Electrophoretic separation of the solubilized contents of the glands yields an uppermost diffuse band of high molecular size, preceded by a stepladder of well-defined peptides, which have been shown to be products of discontinuous translation in three other sets of glands. The luminal contents do not migrate as a discrete and well-defined band as those of the other glands, but rather as a diffuse area, typical of glycosylated proteins. Fibroin synthesis is stimulated by the mechanical depletion of the organism's stored silks, as in other Nephila glands, judged by the increased intensity of the bands and also by the structural alterations seen in cross sections of the glands' tails.

Animals↗
PubMed1995

Involvement of nitric oxide in bone marrow-derived natural suppressor activity. Its dependence on IFN-gamma.

Bone marrow (BM)-derived natural suppressor (NS) cells are strong inhibitors of lymphoproliferative responses. In this study we have assessed the involvement of nitric oxide (NO) in BM-derived NS activity, as detected in cocultures of BM and spleen cells stimulated with B cell (LPS) or T cell (Con A) mitogens. The results indicate that NS activity is readily inhibited by NG-monomethyl-L-arginine, a competitive inhibitor of NO synthase, or N-acetylcysteine, a free radical-scavenging thiol compound. High amounts of nitrite, a stable end product of NO, are detected only in supernatants of Con A- or LPS-stimulated spleen cells cocultured with BM cells enriched in NS activity (Fr3 cells). These amounts (15 to 55 microM) are strongly antiproliferative for both Con A and LPS responses, as was established with a nitrite curve made with a NO donor (sodium nitroprusside). Fr3 cells cultured alone release large quantities of NO and express inducible NO synthase (iNOS) mRNA upon LPS stimulation, but require spleen cells in cultures stimulated with Con A. Anti-IFN-gamma-neutralizing Abs blocked both NO production and NS activity, irrespective of the mitogen used; yet, only exogenous IFN-gamma is unable to promote successful NO production by Fr3 cells, but does induce detectable iNOS mRNA expression in these cells. Taken together the results indicate that: 1) NO is the major mediator of BM-derived NS activity; 2) BM cells enriched in NS activity produce large amounts of NO through an IFN-gamma-dependent iNOS induction.

Acetylcysteine↗
PubMed1995

[Drug prescriptions in general medicine practice].

OBJECTIVE: To find the origin of pharmacological prescriptions written in the primary care ambit, the effect of training on the prescribers and the influence of the organisational structure of the centres where they work on the quality of the drugs prescribed. DESIGN: Observational study of a crossover type. SETTING: Two health centres and two consulting-rooms in Areas 11 and 12, Valencia. MEASUREMENTS AND MAIN RESULTS: The sample calculated corresponded to 664 prescriptions per centre. The origin of the prescription differed, depending on the model, so that in the consulting-rooms the origin of 55% of prescriptions was specialist care, whereas in the health centres this percentage went down to 31%. There were significant differences (p < 0.0001) in the quality of prescription in different organisational structures, but there were no significant differences among professionals with different training. CONCLUSIONS: A high percentage of pharmacological prescriptions have their origin in specialist care. Prescription quality is conditioned basically by the organisational model and is appreciably better in health centres.

Cross-Over Studies↗
PubMed1995

Biotin supplementation affects lymphocyte carboxylases and plasma biotin in severe protein-energy malnutrition.

We studied the effect of a supplement of biotin (10 mg/d) or a placebo under double-blind conditions on plasma biotin concentrations and lymphocyte propionyl CoA carboxylase (PCC) and pyruvate carboxylase (PC) in 22 children with severe protein-energy malnutrition (PEM) (5 with kwashiorkor, 10 with marasmus, and 7 "sugar babies"). There were significant differences between the malnourished and control subjects only for PCC, although not among the three PEM types. Six of the patients had both PC and PCC activities below the lowest of the normal control subjects; there was no correlation between biotin concentrations and carboxylase activities in individual patients. In response to biotin supplementation, the greatest change in lymphocyte carboxylase activities was detected in patients who had abnormally decreased initial carboxylase activities, but the response was not related to initial plasma biotin concentration. These results indicate that these enzyme deficiencies are the result of a nutritionally determined biotin deficiency, that carboxylases and especially PCC are better indicators of the biotin status in individual patients than is the plasma biotin concentration, and that in some malnourished patients biotin deficiency may be rate-limiting in their nutritional homeostasis.

Biotin↗
PubMed1995

[Vascular complications in renal transplantation].

Between the years 1979 and 1992 we a total of 479 renal transplants (RT) were performed. In 62 patients (12.9%) there were some clinically significant vascular complications. These have consisted of: 10 cases of arterial thrombosis (2%); 10 cases of venous thrombosis (2%); 5 cases of arterial and venous thrombosis (1%); 31 cases of arterial stenosis (6.5%); and 6 cases of acute haemorrhage originated at the vascular anastomosis level (1.2%). In all those cases with arterial or venous thrombosis, or both, it was necessary to perform transplantation. The arterial stenosis cases were treated with antihypertensive agents in 13 patients; with endoluminal percutaneous angioplasty (EPA) in other 13 patients and with surgery in 5. Both arterial stenosis and complications from their treatment resulted in 5 transplantations. In all cases with early post-surgical haemorrhage originated at the vascular anastomosis level, a surgical review and suture of bleeding site was performed. A total of 31 grafts (6.5%) were lost as a result of vascular complications.

Adolescent↗
PubMed1995

[Comparative study of single-dose intradural anesthesia and continuous intradural anesthesia with or without fentanyl].

OBJECTIVE: To compare the hemodynamic effects, level of anesthetic blockade and advantages of single-dose versus continuous intrathecal anesthesia with hyperbaric bupivacaine with and without fentanyl. PATIENTS AND METHOD: Prospective study in 45 patients under 65 who were scheduled for elective surgery of the lower abdomen, randomly divided into 3 groups. Group 1 and 2 received continuous intrathecal anesthesia with 10 mg hyperbaric bupivacaine; group 2 also received 25 mcg fentanyl. Patients in group 3 were given a single intrathecal dose of 15 mg hyperbaric bupivacaine. Mean arterial pressure and heart rate were recorded at baseline and 10, 20 and 30 minutes after the start of anesthesia. The level of block achieved was recorded after 10, 30 and 60 minutes. Hemodynamic changes, differences in blockade and side effects were analyzed. RESULTS: Hemodynamic changes were greater in group 2 (fentanyl) than in groups 1 and 3 (p < 0.05), with group 3 showing the greatest degree of hemodynamic stability. Level of blockade was always higher in group 2, with significant differences at 30 min (p < 0.05). Seven and 5 reinjections by catheter were necessary in groups 1 and 2, respectively. Two patients in group 3 required general anesthesia when blockade was inadequate. Apart from pruritus in group 2 (40%), no side effects due to anesthesia were observed. CONCLUSIONS: A single dose intrathecal anesthesia, produces less hemodynamic changes than a continuous intrathecal block. Nevertheless, continuous intrathecal block, allows the maintenance of the block as long as required. The association of fentanyl enhances the hemodynamic changes with no other beneficial effects.

Adult↗
PubMed1995

[Comparison of changes in plasma concentrations of ACTH and beta-endorphin in cholecystectomy under general anesthesia and general plus epidural anesthesia].

OBJECTIVE: To study neuroendocrine response during cholecystectomy under general anesthesia with fentanyl and under general anesthesia with nitrous oxide plus thoracic epidural block, by determining plasma levels of ACTH and beta-endorphin. PATIENTS AND METHODS: This was a prospective study of 2 randomly chosen groups of 7 patients each who were undergoing cholecystectomy. One group received general anesthesia with fentanyl at initial doses of 10 micrograms/kg-1 followed by perfusion of 5 micrograms.kg-1.h-1. The other group received general anesthesia with 60% nitrous oxide in oxygen combined with bupivacaine 0.5% for thoracic epidural blockade. Plasma levels of ACTH and beta-endorphin were determined at the following moments: A, upon arrival in the operating theater; B, after anesthetic induction and intubation; C, after incision; D, 30 minutes after start of surgery; E, after surgery but before extubation, and F, after arrival in the recovery room. Also recorded were mean arterial pressure and heart rate. RESULTS: In both groups we found significantly higher levels of beta-endorphin throughout surgery. The increase was greater, however, in the group receiving combined anesthesia at moments D (p = 0.008) and E (p = 0.008). ACTH levels rose significantly during surgery (p = 0.004) in the combined anesthesia group, whereas there was only a slight increase in the group receiving only general anesthesia (p = NS). beta-endorphin levels increased proportionally more than ACTH levels during combined anesthesia. Hemodynamic stability was acceptable in both groups. CONCLUSION: General anesthesia with fentanyl at the dose used in this study was more effective that combined anesthesia in mitigating the release of ACTH and beta-endorphin during cholecystectomy.

Adrenocorticotropic Hormone↗
PubMed1995

[The physicochemical characterization of the agents isolated during the outbreak of epidemic neuropathy in Cuba. I].

This paper reports on the physical and chemical characteristics of agents isolated from serum samples of patients presenting with epidemic neuropathy. The behaviour of isolated enteroviruses was as described for such viruses. Mild cytopathogenic effects-producing agents behaved in a variable form regarding sensitivity to chloroform; on the other hand they were neither sensitive to phosphonoacetic acid (PAA) nor to guanidine hydrochloride (GHC1) and grew in cells previously treated with bromodeoxyuridine (BDUR). These results suggest the presence of agents resembling enteroviruses and enveloped viruses. Further studies for the characterization of such agents need to be performed.

Acyclovir↗
PubMed1995

[The physicochemical characterization of the strains isolated during the outbreak of epidemic neuropathy in Cuba. II].

The presence of 2 agents such as a Cox A9 strain and another mild cytopathogenic effect-producing strain, both isolated from patients presenting with epidemic neuropathy is reported in this paper. A mild cutopathogenic effect which was propagated in successive dilutions was developed in the dilution 10(-4) by means of the neutralization test of a Coxsackie A9 virus with its homologous hyperimmune serum. A gradient in saccharose was performed in a mild cytopathogenic effect-producing strain and a typical cytopathogenic effect of an Enterovirus developed from one of the fractions passed in tissular cultures in the presence phosphonoacetic acid (PAA). The possible pathogenic role of these viruses are discussed.

Animals↗
PubMed1995

[The factors affecting the growth of the agent, producing a mild cytopathic effect, isolated in patients with epidemic neuropathy].

Certain factors influencing upon the growth of the agent producer of mild cytopathogenic effect and isolated from the cerebrospinal fluid of patients presenting with epidemic neuropathy are described in this paper. It was demonstrated that a concentration of NaHCO3 was essential for the occurrence of the cytopathogenic effect. Determined concentrations of MnCl2 allowed for the visualization of the cytopathogenic effect and increased viral yields.

Animals↗
PubMed1995

[The usefulness of the CLA-1 cell subline for the isolation of the dengue virus].

The live CLA-1 obtained by cloning from the cell live AP-61 (Aedes pseudocutellaris) was used to intend the isolation of dengue virus in 10 serum samples patients in acute phase and clinical diagnosis of dengue. Samples were parallelly inoculated in C6/36 and AP-61 as control systems. Of the 10 samples, 6 were positive in the 3 systems evidencing sensitivity and usefulness for the isolation of the cell subline CLA-1.

Acute Disease↗
PubMed1994

[HIV infection declines among intravenous drug addicts in Barcelona: 1987-1993].

BACKGROUND: The evolution of the prevalence of HIV infection in intravenous drug addicts who initiate hospital detoxication was analyzed. METHODS: Six hundred fifty intravenous drug addicts (535 males, 115 females) were analyzed for HIV and surveyed in regard to demographic variables and the use of drugs over a period of 7 years (1987-1993): age, sex, year of initiation of intravenous drug addiction, length of the habit and year of admission. RESULTS: Most of the subjects were men (82%) with a mean age of 19.7 years at the time of initiation to the use of i.v. drugs and an age of 25.9 years on admission to the unit. The mean time of i.v. drug addiction at admission was 74 months. The characteristics of the patients according to the year of admission were homogeneous in regard to age, length of drug addiction and male/female ratio. More than 50% of the subjects had initiated the use of i.v. drugs during the first half of the last decade. The global prevalence of HIV infection was of 66.3% with no differences being observed between sexes. The frequency of infection was shown to have globally decreased from 1987 to 1993 (p = 0.06) although the rates of HIV infection in women did not significantly modify (p = 0.08) in contrast to that of men (p = 0.05). CONCLUSIONS: The epidemia of HIV infection in intravenous drug addicts may have entered into remission following a decade characterized by a spread in the use of heroin and great diffusion of the disease.

Adult↗
PubMed1994

Detergent-induced reversible denaturation of the photosystem II reaction center: implications for pigment-protein interactions.

Incubation of the D1-D2-cytochrome b559 complex with Triton X-100 modified the protein secondary structure, caused significant spectral modifications, and reduced the formation of light-induced spin-polarized triplet electron paramagnetic resonance (EPR) signal. After 24 h of incubation, the absorption spectrum shifted from 675.5 to 671.5 nm and the fluorescence spectrum shifted from 682 to 672 nm. These shifts were accompanied by an increase in the chlorophyll fluorescence yield and by decreases in the intensity of the circular dichroism in the red region and the secondary electron transport activity. The intensity of the light-induced triplet EPR signal was also markedly reduced in the same experimental conditions. Substitution of dodecyl beta-maltoside for Triton X-100 reversed all the above-mentioned parameters to the values exhibited by the native D1-D2-Cyt b559 complex, including the characteristic triplet EPR signal. We concluded that all observed changes were due to the destruction of P680 with Triton X-100 and to the reestablishment of P680 in the presence of dodecyl beta-maltoside. The easier but certainly not the only possible explanation to all these phenomena is to consider a dimeric structure for P680, at least in its ground state, where interactions take place within the two dimeric chromophores and with the apoprotein. Such a dimeric structure would be very sensitive to small modifications of the P680 domain, which convert the dimer absorbing at 680 into two chlorophyll monomers absorbing near 670 nm. The dodecyl beta-maltoside reestablished the structure of the native P680 domain.

Carotenoids↗
PubMed1994

Core antenna complexes, CP43 and CP47, of higher plant photosystem II. Spectral properties, pigment stoichiometry, and amino acid composition.

The core antenna complexes of photosystem II, CP43 and CP47, were purified from two higher plants by anion-exchange chromatography, using a combination of the chaotropic agent LiClO4 and the nonionic detergent beta-dodecyl maltoside. The Qy transition was resolved at 48 K into two main bands near 682.3 and 671.5 nm for CP43, while the CP47 spectrum showed a more complex structure with main bands at 688, 681.2, 676, 667, and 661 nm. Emission bands (77 K) were detected at 683 and 695 nm for CP43 and CP47, respectively. Fluorescence excitation spectra showed high efficiency of energy transfer between the different transitions of the chlorophylls and a somewhat lower efficiency from beta-carotene. The circular dichroism spectrum of CP47 indicated the presence of excitonic interactions between some chlorophylls. In contrast, CP43 showed a single negative circular dichroism band at 670 nm. The pigment content of the complexes was determined by both spectroscopic measurements and HPLC. Contents of 18 chlorophylls a and 5 beta-carotenes per CP43 polypeptide and 19 chlorophylls a and 3 beta-carotenes per CP47 polypeptide were found, using the methods of Lowry or Bradford for protein quantitation. When the protein concentration was determined from the amino acid analysis, 20 chlorophylls a and 5 beta-carotenes per CP43 and 21-22 chlorophylls a and 4 beta-carotenes per CP47 were obtained. Thus, a content of 46-48 chlorophylls a was obtained for the core complex, assuming 4-6 chlorophylls per reaction center, in agreement with the composition obtained experimentally using a highly purified oxygen-evolving core complex.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1994

Inhibition of bone marrow-derived natural suppressor activity by glucocorticoids and its reversal by IFN-gamma or IL-2.

Natural suppressor (NS) activity is mediated by cells (NS cells) of bone marrow origin with ability to suppress nonspecifically proliferative responses of lymphocytes. Here we show that pharmacologic concentrations (10(-6)-10(-8) M) of glucocorticoids (GC) greatly inhibit NS activity, as detected by coculturing bone marrow and spleen cells stimulated with B cell (LPS) or T cell (concanavalin A) mitogens. Progesterone antagonizes GC-mediated inhibition of NS activity, suggesting that GC were acting through a receptor-dependent mechanism. A prior treatment of NS cells with GC (10(-5) M) has no effect on the NS activity mediated by these cells. GC are required in culture during the first 24 hr of the suppressor assay. Addition of low amounts of IFN-gamma to GC-treated cultures fully reverses NS cell-mediated suppression. IL-2 produces a reversion as well, while addition of IL-3 or IL-4 does not prevent the GC effect. Neutralizing anti-IFN-gamma antibodies, but not anti-IL-2 or anti-TGF-beta, greatly inhibit NS activity in absence of GC. Taken together, these results indicate that GC inhibit NS activity by impairing endogenous cytokine production required to obtain successful NS cell activation, and not by acting directly on NS cells (i.e., inhibiting the secretion of putative NS factors). Among the cytokines involved in NS cell activation, IFN-gamma appears to be critical, since its addition readily overrides the GC effect and its neutralization results in strong inhibition of NS activity.

Animals↗