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Biomedical subjects

N Vázquez

Publications and source records attributed to N Vázquez.

At least 19 recordsLinked to original sources
PubMed2003

In-use evaluation of Perasafe compared with Cidex in fibreoptic bronchoscope disinfection.

The mycobactericidal activity of Perasafe (0.26% peracetic acid) was compared with that of Cidex (2% alkaline glutaraldehyde) by an in-use test. Fibreoptic bronchoscopes were artificially contaminated with Mycobacterium tuberculosis or Mycobacterium avium-intracellulare in sputum and, after manual pre-cleaning with a neutral soap, 10 and 20 min disinfection periods were tested. Perasafe was as effective as Cidex, thus requiring a 10 min disinfection period against M. tuberculosis and 20 min against M. avium-intracellulare. The results demonstrate that Perasafe is an effective disinfectant for use in reprocessing fibreoptic bronchoscopes.

Bronchoscopes↗
PubMed2002

Influence of fasting on the effects of ischemic preconditioning in the ischemic-reperfused rat heart.

The effects of fasting and ischemic preconditioning (IP) on heart function of Langendorff-perfused rat hearts exposed to 25 min global ischemia plus 30 min reperfusion (RP), were correlated with lactate release and tissue-levels of long-chain acyl carnitine (LCCa) and CoA (LCCoA). IP was achieved by a 3 min ischemia plus a 5 min reperfusion cycle. Creatine kinase leakage was measured to assess the extent of cardiac injury. Fasting reduced the ischemic-induced contracture, improved RP recovery of mechanical function, reduced lactate release and increased the end-ischemia LCCoA and LCCa levels. Both in the fed and the fasted rat hearts IP delayed the pacemaker depression, reduced the amplitude of ischemic contracture and improved the RP recovery of contraction. However, IP reduced creatine kinase and lactate release only in the fed rat hearts. IP had no effects on tissue LCCa and LCCoA in both groups. These data suggest that: 1) beneficial effects of fasting may be ascribed, at least in part, to a reduced lactate production which may attenuate ischemic myocyte acidification and to the accumulation of fatty acyl esters which would favour citric acid cycle replenishment during RP. 2) beneficial effects of IP could be in part explained by the reduction of lactate production in the fed group although data obtained with the fasted rat heart indicate that another mechanisms must also be involved in the effects of IP. 3) accumulation of LCCoA and LCCa is not involved in the noxious effects of ischemia as well as in the protection effected by IP.

Animals↗
PubMed2001

Mutational analysis of patients with p47-phox-deficient chronic granulomatous disease: The significance of recombination events between the p47-phox gene (NCF1) and its highly homologous pseudogenes.

OBJECTIVE: The aim of this study was to determine the molecular basis of p47-phox-deficient chronic granulomatous disease (CGD), the most common autosomal recessive form of the disease. CGD is an inherited condition characterized by defective oxygen radical production due to defects in the phagocyte nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. Mutational analysis of p47-phox-deficient CGD patients previously demonstrated that the majority of patients have a GT dinucleotide (Delta GT) deletion at the start of exon 2, a signature sequence also observed in the highly homologous pseudogenes of NCF1. MATERIALS AND METHODS: We performed genetic analysis of NCF1 and its pseudogenes using genomic DNA in 29 p47-phox-deficient CGD patients from 22 separate families. First-strand cDNA analysis was performed in 17 of the 29 patients. RESULTS: We confirmed the significance of the Delta GT mutation; in 27 of 29 patients, only the Delta GT sequence was detectable. All but one of the 27 had at least one additional signature sequence, specific to the pseudogene, in either intron 1 and/or intron 2. We extended our analysis to look at signature sequence differences in exons 6 and 9 and detected both the wild-type and pseudogene sequences in all patients tested. CONCLUSIONS: Although detection of only Delta GT sequence accounts for over 85% of affected patients, the molecular basis is most likely due to partial cross-over events between the wild-type and pseudogene(s) of p47-phox at different recombination sites. Our results suggest that complete gene conversion or deletion of the p47-phox gene (NCF1) occurs rarely, if it all.

Base Sequence↗
PubMed2001

Functional and molecular characterization of the K-Cl cotransporter of Xenopus laevis oocytes.

The K-Cl cotransporters (KCCs) have a broad range of physiological roles, in a number of cells and species. We report here that Xenopus laevis oocytes express a K-Cl cotransporter with significant functional and molecular similarity to mammalian KCCs. Under isotonic conditions, defolliculated oocytes exhibit a Cl(-)-dependent (86)Rb(+) uptake mechanism after activation by the cysteine-reactive compounds N-ethylmaleimide (NEM) and mercuric chloride (HgCl(2)). The activation of this K-Cl cotransporter by cell swelling is prevented by inhibition of protein phosphatase-1 with calyculin A; NEM activation of the transporter was not blocked by phosphatase inhibition. Kinetic characterization reveals apparent values for the Michaelis-Menten constant of 27.7 +/- 3.0 and 15.4 +/- 4.7 mM for Rb(+) and Cl(-), respectively, with an anion selectivity for K(+) transport of Cl(-) = PO(4)(3-) = Br(-) > I(-) > SCN(-) > gluconate. The oocyte K-Cl cotransporter was sensitive to several inhibitors, including loop diuretics, with apparent half-maximal inhibition values of 200 and 500 microM for furosemide and bumetanide, respectively. A partial cDNA encoding the Xenopus K-Cl cotransporter was cloned from oocyte RNA; the corresponding transcript is widely expressed in Xenopus tissues. The predicted COOH-terminal protein fragment exhibited particular homology to the KCC1/KCC3 subgroup of the mammalian KCCs, and the functional characteristics are the most similar to those of KCC1 (Mercado A, Song L, Vazquez N, Mount DB, and Gamba G. J Biol Chem 275: 30326--30334, 2000).

Amino Acid Sequence↗
PubMed2001

Alternatively spliced isoform of apical Na(+)-K(+)-Cl(-) cotransporter gene encodes a furosemide-sensitive Na(+)-Cl(-)cotransporter.

In the absence of vasopressin, medullary thick ascending limb cells express a K(+)-independent, furosemide-sensitive Na(+)-Cl(-) cotransporter that is inhibited by hypertonicity. The murine renal specific Na(+)-K(+)-2 Cl(-) cotransporter gene (SLC12A1) gives rise to six alternatively spliced isoforms. Three feature a long COOH-terminal domain that encodes the butmetanide-sensitive Na(+)-K(+)-2 Cl(-) cotransporter (BSC1-9/NKCC2), and three with a short COOH-terminal domain, known as mBSC1-A4, B4, or F4 (19). Here we have determined the functional characteristics of mBSC1-A4, as expressed in Xenopus laevis oocytes. When incubated at normal oocyte osmolarity (approximately 200 mosmol/kgH(2)O), mBSC1-4-injected oocytes do not express significant Na(+) uptake over H(2)O-injected controls, and immunohistochemical analysis shows that the majority of mBSC1-4 protein is in the oocyte cytoplasm and not at the plasma membrane. In contrast, when mBSC1-4 oocytes are exposed to hypotonicity (approximately 100 mosmol/kgH(2)O), a significant increase in Na(+) uptake but not in (86)Rb(+) uptake is observed. The increased Na(+) uptake is Cl(-) dependent, furosemide sensitive, and cAMP sensitive but K(+) independent. Sodium uptake increases with decreasing osmolarity between 120 and 70 mosmol/kgH(2)O (r = 0.95, P < 0.01). Immunohistochemical analysis shows that in hypotonic conditions mBSC1-A4 protein is expressed in the plasma membrane. These studies indicate that the mBSC1-A4 isoform of the SLC12A1 gene encodes a hypotonically activated, cAMP- and furosemide-sensitive Na(+)-Cl(-) cotransporter. Thus it is possible that alternative splicing of the BSC1 gene could provide the molecular mechanism enabling the Na(+)-Cl(-)-to-Na(+)-K(+)-2Cl(-) switching in thick ascending limb cells.

1-Methyl-3-isobutylxanthine↗
PubMed1998

[The value of exercise echocardiography in the diagnosis of coronary disease in patients with left heart branch block in the bundle of His].

OBJECTIVE: To assess the diagnostic value of exercise echocardiography in patients with complete left bundle branch block and clinical suspicion of coronary artery disease. MATERIAL AND METHODS: Among 1,176 exercise echocardiograms performed from May of 1994 to November of 1996, 92 showed complete left bundle branch block in the resting electrocardiogram. We retrospectively analyzed data of 23 patients who had coronary angiography performed within 6 weeks of the exercise echo (19 males and 4 females, age 62 +/- 8, resting ejection fraction 52 +/- 10%). Previous acute myocardial infarction was demonstrated in 8 of them. The development of new or worsening regional dysfunction was considered an ischaemic response on exercise echo; whereas we assumed that there was significant coronary artery disease on the coronariography whether there was > or = 1 vessel disease in patients without previous myocardial infarction or > or = 2 vessel disease in patients with previous infarction. RESULTS: Ten patients showed multivessel disease (> or = 2 vessels, 6 with previous infarction); 5 one-vessel disease; and 8 non significant coronary artery disease. Exercise echocardiography sensitivity for ischaemia detection in the entire group was 86% (95% confidence interval 67-100%); the specificity was 67% (36-98%), predictive value of a positive test was 80% and predictive value of a negative test was 75%. Sensitivity for the detection of > 50% stenosis in the left anterior descending coronary territory was 92% (76%-100%) and specificity 64% (35%-92%); for right coronary artery sensitivity was 80% (55%-100%) and specificity 77% (54%-100%); and for left circumflex artery sensitivity was 70% (42%-98%) and specificity 69% (44%-94%). CONCLUSIONS: Exercise echocardiography may be useful in the evaluation of patients with left bundle branch block and clinical suspicion of coronary artery disease; with good sensitivity and low specificity.

Aged↗
PubMed1998

Interleukin-15 augments superoxide production and microbicidal activity of human monocytes against Candida albicans.

Interleukin-15 (IL-15) is a newly described cytokine that shares biological activities with IL-2. We report here results demonstrating the ability of IL-15 to enhance superoxide production and antifungal activity of human monocytes. After 18 and 48 h of treatment with IL-15, human elutriated monocytes manifested enhanced superoxide production in response to either phorbol myristate acetate or opsonized Candida albicans blastoconidia. Similar results were obtained when monocytes were treated with IL-2, but to a lesser extent. Combination studies with IL-15 and IL-2 showed no additive or synergistic effects. Following incubation of monocytes with IL-15 for 18 h, there was no significant increase in mRNA transcripts for components of the NADPH oxidase complex, p40-phox, p47-phox, and gp91-phox, suggesting a posttranscriptional modulation of enhanced superoxide production. Antibodies against the gamma chain of the IL-2 receptor and, to a lesser extent, against the beta chain partially abrogated the IL-15-mediated enhanced superoxide production. Additionally, human monocytes showed enhanced killing activity against C. albicans after 18 h of incubation with IL-15 or IL-2, but this treatment did not enhance the ability of these cells to phagocytose the organism. In addition, the enhanced fungicidal activity seen after 18 h of treatment was no longer detectable after 48 h of cytokine treatment. Culture supernatants from the IL-15-treated monocytes were assayed for the presence of other proinflammatory cytokines. IL-15 treatment did not induce the release of detectable levels of tumor necrosis factor alpha, IL-1beta, or IL-12. Our results indicate that IL-15 upregulates the microbicidal activity of human monocytes against C. albicans.

Candida albicans↗
PubMed1998

[Wiktor coronary stent for elective placement with an antiaggregation regimen. WINE study. WINE Group Study].

INTRODUCTION AND OBJECTIVES: The main problems associated with coronary stent implantation are subacute thrombosis and vascular and hemorrhagic complications due to the intensive anticoagulant regime. We studied the complications and the six-month restenosis rate after the elective implantation of a Wiktor stent in patients treated only with antiplatelet drugs. PATIENTS AND METHODS: The WINE study is an open, observational, multicenter study that included 368 patients (380 lesions) from 11 Spanish hospitals. All patients were treated with aspirin (125-325 mg/day) and ticlopidine (250 mg/12 h for 4 weeks). After hospitalization, a clinical control and clinical and angiographic controls were performed at one and six months respectively. RESULTS: 27 patients were excluded after the procedure because of failed delivery of the stent (5 cases), suboptimal angiographic result (15 cases) or lack of adherence to the antithrombotic regime (7 cases). Among the 341 patients with an adequate result most lesions (76.2%) were type B, including 39.1% type B2 and 8.5% type C. Subacute stent occlusion occurred in two patients (0.6%). Seven patients (2.1%) had vascular complications related to the arterial puncture. No major hemorrhagic complications needing transfusion were found. At six months 64 patients (19.8%) showed angiographic restenosis. CONCLUSIONS: When the angiographic result after Wiktor stent placement is adequate, the therapy with aspirin and ticlopidine is associated with a very low stent thrombosis rate as well as with a low rate of vascular complications and 6 month angiographic restenosis.

Adult↗
PubMed1995

[A paradoxical intraventricular gradient in a patient with atypical hypertrophic myocardiopathy].

A paradoxic diastolic intraventricular flow (directed from apex to base), caused by a pressure gradient between a small apical aneurysm and the main left ventricular cavity, connected by a narrow muscular tunnel, was detected by Doppler echocardiography in a 69 year old male with apical hypertrophic cardiomyopathy and effort angina. Coronary arteriography was normal and the clinical, electrocardiographic, echocardiographic and angiocardiographic features of the patient were otherwise typical of apical hypertrophic cardiomyopathy. Paradoxic diastolic gradients have been occasionally described in patients with hypertrophic cardiomyopathy, and indicate the existence of a sequestered apical cavity, which is frequently not detected by echocardiography. Identification of these gradients may have important clinical implications, since they have been related with a higher incidence of embolic events, severe ventricular arrhythmias and myocardial ischaemia and necrosis.

Aged↗
PubMed1994

[Fiberoptic bronchoscope disinfection with glutaraldehyde phenolate in 1:8 solution].

We evaluated the efficacy of phenolated glutaraldehyde in a 1:8 solution for the disinfection of bronchofibroscopes that were highly contaminated with Serratia marcescens and Pseudomonas aeruginosa. An Olympus BF-P10 bronchofibroscope was contaminated with artificial samples containing one of the aforementioned microorganisms in concentrations nearing 10(8) colony forming units per milliliter (cfu/ml). The instruments were then washed with soap and water and submerged in a 1:8 solution of phenolated glutaraldehyde. Samples were taken for culturing after contamination, after washing, and after 10, 15 and 30 min in the disinfectant solution. The level of cfu/ml in the cultures was measured and the definition of failure-to-disinfect was a finding of > or = 1 cfu/ml after each experimental procedure. Twenty procedures, 10 for each microorganism, were carried out. Washing of the bronchofibroscope afforded significant elimination of microorganisms and no colony growth was observed in cultures after 10 min submersion in phenolated glutaraldehyde. We conclude that immersion in a 1:8 solution of phenolated glutaraldehyde after careful washing is a valid way to disinfect bronchofibroscopes that are highly contaminated with S. marcescens and P. aeruginosa.

Bronchoscopes↗
PubMed1992

Multicenter double-blind trial of gabexate mesylate (FOY) in unselected patients with acute pancreatitis.

A multicenter, randomized, double-blind trial was carried out to evaluate the efficacy of gabexate mesylate (FOY) in acute pancreatitis. One hundred unselected patients were randomly allocated into two groups: 51 were assigned to receive FOY (12 mg/kg/day as continuous intravenous infusion for a minimum of 4 days and a maximum of 12 days), and 49 were allocated to placebo. The groups were comparable in demographic, clinical and biochemical parameters, etiology of pancreatitis, and disease severity, which was generally mild. Gallstones were the main etiological factor. All patients received fluid and electrolyte replacement, analgesia and nasogastric suction for at least 48 h after admission. Experimental therapy was initiated no later than 12 h after the beginning of symptoms. The results showed no statistically significant differences between the two groups with respect to the evolution of clinical and biochemical parameters, analgesic requirements, development of complications, hospitalization time or mortality at completion of the trial. In conclusion, early treatment with FOY does not appear to have any demonstrable beneficial effects in acute pancreatitis.

Acute Disease↗
PubMed1991

[Comparative study of sucralfate and ranitidine in the treatment of bleeding duodenal ulcer].

Sixty patients with bleeding duodenal ulcers were randomized to treatment with sucralfate or ranitidine. Endoscopy was performed in all patients within 24 hours from admission. Acute phase outcome was similar in both groups. Four patients in the sucralfate group and 1 patient in the ranitidine group rebled and required surgical treatment (NS). Healing rate at 6 weeks was 88% with sucralfate and 96.6% with ranitidine. Relapsing rate without maintenance therapy at 6 and 12 months was 21.1% and 42.1% for sucralfate-treated patients and 33.3% and 56.5% for ranitidine-treated patients (NS). Sucralfate-treated patients had a significantly lesser relapsing rate at 12 months compared to ranitidine treated patients, in the smokers group.

Adult↗