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Biomedical subjects

N García

Publications and source records attributed to N García.

At least 73 records · Page 4Linked to original sources

Oxygen free-radicals mediate the damaging effect of ultraviolet light on membrane mitochondria.

This paper reports evidence that exposure of mitochondria to near-ultraviolet light inhibits electron transport, collapses the electric gradient, and increases non-specific membrane permeability to matrix solutes such as Ca2+. Membrane energization, as well as superoxide dismutase and catalase avoid membrane leakiness. Increased permeability correlates with a diminution in the titrated thiol groups. Plausibly the pore is formed through the formation of sulfhydryl bridges by the action of UV light-derived oxygen-centered free- radicals on membrane proteins.

Animals↗

Two-day quadruple therapy for cure of Helicobacter pylori infection: a comparative, randomized trial.

OBJECTIVE: We sought to compare a 2-day quadruple therapy with a 14-day triple therapy in the treatment of Helicobacter pylori infection. METHODS: Eighty-one consecutive patients with an endoscopically diagnosed peptic ulcer and demonstrated infection by H. pylori were included in the study. Patients were randomized to receive omeprazole 40 mg b.i.d., amoxicillin 2.5 g once daily, metronidazole 500 mg t.i.d., and bismuth subcitrate 360 mg t.i.d. for 2 days, followed by omeprazole 20 mg once daily for 6 additional days (Group 1) or a 14-day course of omeprazole 20 mg b.i.d., amoxicillin 1 g t.i.d., and metronidazole 500 mg t.i.d. (Group 2). Eradication was evaluated by antral biopsy and rapid urease test at 2 months after therapy and by C13-urea breath test after a year. RESULTS: Two patients were lost to follow-up at 2 months. Intention-to-treat analysis showed that H. pylori infection was cured in 29 of 42 patients (69%; 95% CI: 53-82%) in Group 1 versus 36 of 39 (92%; 95% CI: 78-98%) of patients in Group 2 (p = 0.009). Per-protocol analysis showed a cure rate of 71% (95% CI: 55-84%) (29/41 patients) and 95% (95% CI: 81-99%) (36/38 patients), respectively (p = 0.007). Fifty-five of 65 cured patients returned 1 year after treatment (26 in Group 1, 29 in Group 2). All but one in Group 2 remained cured. There were no significant differences in compliance (88% in Group 1 versus 92% in Group 2) or in the presence of side effects (27%; 95% CI: 15-43% versus 41%; 95% CI: 26-58%; ns). CONCLUSION: Two-day quadruple therapy is significantly less effective than 2-wk triple treatment.

Adolescent↗

The flagellar switch genes fliM and fliN of Rhodobacter sphaeroides are contained in a large flagellar gene cluster.

In this work, the genes that encode the FliM and FliN proteins of Rhodobacter sphaeroides were characterized. These genes are part of a large flagellar gene cluster in which six additional open reading frames encoding products homologous to FliL, FliO, FliP, FliQ, FliR, and FlhB proteins from other bacteria were identified. The inactivation of the fliM gene gave a nonflagellate phenotype (Fla-), suggesting that FliM is required for flagellar assembly. Complementation analysis of this fliM mutant indicated that fliM and fliN transcription starts beyond the 5' end of fliK and terminates after fliN.

Amino Acid Sequence↗

[Seven-day omeprazole, clarithromycin, and amoxicillin for the therapy of Helicobacter pylori infection].

BACKGROUND: There are few series reporting efficacy of seven-day therapy with omeprazole, amoxicillin and clarithromycin for cure of Helicobacter pylori infection in Spain. The aim of the present study was to evaluate the efficacy of this treatment to eradicate H. pylori infection. PATIENTS AND METHODS: One hundred consecutive patients with peptic ulcer disease and H. pylori infection were evaluated for eradication therapy between January and November 1996. Four of them were excluded because of reported penicillin allergy. The remaining 96 patients received a seven days course of omeprazole 20 mg/12h, clarithromycin 500 mg/12h and amoxicillin 1 g/12h. The efficacy of the treatment was evaluated at 2-4 months after therapy either by endoscopic biopsy or by 13C urea breath-test. RESULTS: Seventy-eight patients were found to be cured at the control evaluation. Intention to treat analysis showed a cure rate of 81.3% (95% CI: 74-89%). Per protocol analysis showed a cure rate of 85.7% (95% CI: 79-93%)--78 out of 91 patient who returned for follow-up-. Compliance with the treatment was good in 94.5% of patients. Five patients presented mild side effects (diarrhea, abdominal pain, oral candidiasis and metallic taste). None of them had to interrupt the treatment. CONCLUSION: Seven-day therapy with omeprazole, amoxicillin and clarithromycin achieves a 85% cure rate of H. pylori infection in our area.

Aged↗

Lovastatin decreases prolactin and growth hormone gene expression in GH4C1 cells through a cAMP dependent mechanism.

The heterotrimeric G protein Gs couples several surface ligand receptors to cAMP production, as well as to both growth hormone (GH) and prolactin (PRL) gene expression in pituitary and GH cells. It has been shown that constitutively active alpha s stimulates transient expression of both PRL- and GH- chloramphenicol acetyl transferase (CAT) constructions, which indicates that both the PRL and GH promoter regions are under the influence of signal pathways mediated by alpha s. We have previously shown that the cholesterol lowering drug lovastatin decreases both the amount of G alpha s subunit in the membrane and the adenylyl cyclase activity in GH4C1 cells. Thus, we tried to verify whether that decrease in alpha s levels could affect PRL and GH secretion, as well as the expression of PRL- and GH-CAT constructions. Since the regulation of these two genes is dependent on the pituitary specific transcription factor Pit-1, the effect of lovastatin on the expression of Pit-1-CAT constructions was also studied. Our results show that lovastatin decreased the basal expression of these three cAMP-responsive genes in GH4C1 cells, being partially reversed by the addition of mevalonate to the culture medium. This effect of lovastatin on the promoter activities of the transfected constructions was also observed in PRL and GH secretion to the medium, suggesting that this drug produces similar changes in the endogenous promoters of both hormones. Moreover, the presence of lovastatin did not prevent the response to the cAMP activator forskolin, indicating that the main effect of this drug could be exerted through upstream adenylyl cyclase. In conclusion, our data indicate that lovastatin decreases the basal expression of Pit-1 and consequently of both GH and PRL genes through a mechanism probably mediated by the decrease of G alpha s levels in the cell membrane. Taken together, these results suggest that the activity of membrane heterotrimeric G proteins regulates the basal transcription of specific cellular genes in GH4C1 cells. Moreover the effects of lovastatin may be taken into account in the study of constitutively endocrine disorders associated with an increased secretion of either PRL or GH.

Animals↗

Computer simulation of time-gated transillumination and reflection of biological tissues and tissuelike phantoms.

A simulation technique is employed to explore the possibility of locating millimeter-sized objects, immersed in turbid media, from time-gated measurements of the transmitted or reflected light. The simulation results for tissuelike phantoms are compared to experimental transillumination data and excellent agreement is found. Simulations of time-gated reflection experiments show that it is possible to detect objects of 1 mm diameter. This may open new possibilities for medical diagnosis of breast cancer in an early stage.

Algorithms↗

Production of interleukin-2 in response to synthetic peptides from hepatitis C virus E1 protein in patients with chronic hepatitis C: relationship with the response to interferon treatment.

BACKGROUND/AIMS: The role of cellular immunity in the clearance of hepatitis C virus after interferon therapy has not yet been elucidated. Here, we analyzed the T cell response to peptides from hepatitis C virus E1 protein in untreated and interferon-treated patients with chronic hepatitis C virus infection. METHODS: We used thirty-six 15-mer synthetic peptides from hepatitis C virus E1 protein (genotype 1a) in a sensitive interleukin-2 production assay in two groups of controls (healthy seronegative individuals and patients with liver diseases unrelated to hepatitis C virus), and three groups of patients with chronic hepatitis C: nine patients who cleared the virus after interferon treatment (group 1), nine patients who failed to respond to the therapy (group 2) and nine previously untreated patients (group 3). RESULTS: None of the controls responded to any of the peptides tested, whereas 8/9 (88%) of patients from group 1 responded positively. In contrast, only 2/9 (22%) of patients from group 2 showed peptide recognition. In group 3, 5/9 patients (55%) displayed positive response against E1 peptides. When E1 peptides from the sequence corresponding to genotype 1b (the commonest in patients who were non-responders to interferon) were tested in nine additional interferon-resistant patients (group 2*) a positive response was detected in only three of them (33%). CONCLUSIONS: T cell recognition of hepatitis C virus E1 peptides in patients with chronic hepatitis C who exhibit sustained response to interferon therapy is increased as compared with interferon-resistant cases, suggesting that T cell immunity to hepatitis C virus structural proteins may play a role in the clearance of this viral infection.

Adult↗

Anion exchanger immunoreactivity in human salivary glands in health and Sjögren's syndrome.

Salivary gland ducts play a relevant role in saliva secretion through transport processes. Na(+)-independent chloride-bicarbonate anion exchangers (AE) may be involved in these processes by generating ion fluxes into the salivary secretion. In Sjögren's syndrome, a disorder with gland dysfunction, there might be an impaired expression of AE proteins. Here we study AE immunoreactivities in human salivary glands, both in health and in Sjögren's syndrome. Immunohistochemistry was carried out on salivary glands from normal subjects and patients with Sjögren's syndrome, using two monoclonal antibodies against AE1 and AE2. Normal salivary glands showed AE2 immunoreactivity, which was restricted to the epithelium of the ducts, with no staining at the acini. A strong positivity was seen in the basolateral portion of the striated ducts, while interlobular duct cells showed a discrete positivity at their apical pole. In salivary glands from most of the patients with Sjögren's syndrome, AE2 immunoreactivity was absent in the ducts as well as in the acini. In both normal and diseased salivary glands, AE1 immunoreactivity was only located at the erythrocyte membrane. The recently reported AE0 was discarded because no AE0 message was found in salivary glands by reverse transcription polymerase chain reaction. In conclusion, AE2 immunoreactivity is observed in the ducts of normal salivary glands, particularly in the striated ducts. AE2 immunoreactivity is virtually absent in salivary glands from patients with Sjögren's syndrome, which may reflect either a loss of AE2 after inflammatory atrophy, or a primary defect occurring in the disease.

Adult↗

ST-segment computerized monitoring before and after angioplasty: clinical correlation with recurrent angina during the short-term follow-up.

The purpose of this study was to determine whether computerized ST-segment monitoring previous to percutaneous transluminal coronary angioplasty (PTCA) and after performance of this procedure may be useful to discern a pattern of recurrent angina. For this purpose, we analyzed 57 patients (11 women and 46 men, mean age 60 years) before and after treatment with balloon procedure. These patients were followed up during the next 3 months. A computerized electrocardiographic (ECG) device was used which was capable of recording simultaneously all 12 leads at rest. It was programmed to store a complete ECG every 5 min and was capable of detecting any abnormal ST alteration > than 0.5 mV at 80 ms after J junction, including R-wave amplitude. Measurements were started before (mean time 7.26 h) and after (mean time 7.96 h) the procedure. The value for ST amplitude at the J junction was used as the 0 point; then the most negative depression or the most positive elevation value was considered as the most abnormal ST alteration during monitoring. The patients were followed up for 3 months for the purpose of recognizing recurrent angina or establishing the occurrence of death. Twelve patients (30%) had recurrent angina. Discriminant function analysis revealed that ST monitoring in these patients showed significant difference after PTCA in comparison with controls, both in the frontal plane [ST depression 170 +/- 52 mV vs. 231 +/- 23 (p = 0.02)] and in precordial leads [176 +/- 16 vs. 80 +/- 6.19 mV (p = 0.0001)].(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

In vivo biological activity of recombinant Der p II allergen of house-dust mite.

The cDNA coding for one of the major allergens of Dermatophagoides pteronyssinus, Der p II, has been cloned and expressed in Escherichia coli as a fusion protein with glutathione S-transferase. The recombinant material (r Der p II) was tested in the skin of house-dust allergic patients, and was found to be almost as active as the purified native allergen (n Der p II) in stimulating immediate hypersensitivity reactions. The positivity to r Der p II in these patients, who were selected for their skin-test reactivity to house-dust extract (HDE) and whole mite extract (WME), was over 60%, and 80% of their sera contained detectable IgE antibody against the recombinant allergen. The level of specific IgE antibody against r Der p II was a mean of 40% of that against WME in the sera of patients who were skin test positive to both allergen preparations. In contrast to the house-dust allergic patients, none of a group of allergic patients whose clinical history did not implicate house dust, and who were skin test negative to HDE or WME, were positive to r Der p II. Of interest was the observation that only 37% of a group of subjects who were skin test positive to HDE and WME, but who reported no clinical history of allergic disease upon natural exposure to house dust, reacted to r Der p II. These results demonstrate the biological activity of r Der p II, and indicate, in persons skin test positive to house-dust mite extract, an association between reactivity to Der p II and the manifestation of clinical symptoms.

Adolescent↗

[Tobacco dependence and its relation to certain variables in an urban basic health area].

OBJECTIVE: The prevalence of habitual tobacco use in our area and its relationship to other epidemiological variables. DESIGN: A highly structured interview was given to a random sample from the area in order to make a descriptive study of smokers' characteristics. Beforehand there had been: a pre-interview, training of the interviewers, reliability. SETTING: The Arturo Eyries Base Health Area in Valladolid. PARTICIPANTS: A random sample of 246 people over 14, extracted from a sampling background numbering 14,200. INTERVENTION: Items related to tobacco addiction and included in the interview. MEASUREMENTS AND MAIN RESULTS: 43.9% +/- 5 of our population smoked, consuming an average of 16.4 +/- 10 (mean +/- SD) cigarettes per day. The average starting age was 17.2 +/- 5.4, with males starting earlier. The highest percentage of smokers was found in the 30-39 age group, where female smokers exceeded female non-smokers. The typical smoker's profile is that of a married middle-aged man or woman, of average education and able to work. CONCLUSIONS: We obtained a section of the population at risk, clearly defined for health purposes.

Adolescent↗