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J Castillo

Publications and source records attributed to J Castillo.

At least 55 records · Page 3Linked to original sources
PubMed2003

Pion-Kaon correlations in central Au+Au collisions at square root [sNN] = 130 GeV.

Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[s(NN)]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.

Journal Article↗
PubMed2003

Three-pion Hanbury Brown-Twiss correlations in relativistic heavy-ion collisions from the STAR experiment.

Data from the first physics run at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory, Au+Au collisions at sqrt[s(NN)]=130 GeV, have been analyzed by the STAR Collaboration using three-pion correlations with charged pions to study whether pions are emitted independently at freeze-out. We have made a high-statistics measurement of the three-pion correlation function and calculated the normalized three-particle correlator to obtain a quantitative measurement of the degree of chaoticity of the pion source. It is found that the degree of chaoticity seems to increase with increasing particle multiplicity.

Journal Article↗
PubMed2003

Transverse-momentum and collision-energy dependence of high-pT hadron suppression in Au+Au collisions at ultrarelativistic energies.

We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<p(T)<12 GeV/c. The collision energy dependence of the yields and the centrality and p(T) dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of p(T)-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.

Journal Article↗
PubMed2003

Evidence from d+Au measurements for final-state suppression of high-p(T) hadrons in Au+Au collisions at RHIC.

We report measurements of single-particle inclusive spectra and two-particle azimuthal distributions of charged hadrons at high transverse momentum (high p(T)) in minimum bias and central d+Au collisions at sqrt[s(NN)]=200 GeV. The inclusive yield is enhanced in d+Au collisions relative to binary-scaled p+p collisions, while the two-particle azimuthal distributions are very similar to those observed in p+p collisions. These results demonstrate that the strong suppression of the inclusive yield and back-to-back correlations at high p(T) previously observed in central Au+Au collisions are due to final-state interactions with the dense medium generated in such collisions.

Journal Article↗
PubMed2003

Narrowing of the balance function with centrality in Au+Au collisions at the square root of SNN = 130 GeV.

The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.

Journal Article↗
PubMed2003

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV.

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Journal Article↗
PubMed2003

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC.

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Journal Article↗
PubMed2003

Transcranial Doppler sonography in fulminant hepatic failure.

UNLABELLED: The clinical course of patients with fulminant hepatic failure (FHF) is often worsened by the presence of cerebral edema and endocranial hypertension. In spite of the multiple studies using Transcranial Doppler Sonography (TCDS), few have shown the cerebral blood flow (CBF) pattern among patients with encephalopathy resulting from FHF. OBJECTIVE: Our objective was to characterize the CBF pattern in these patients through the use of TCDS to provide therapeutic strategies. METHOD: The TCDS pattern was assessed in five patients diagnosed with FHF and compared with a control group who displayed critical neurologic conditions not associated with FHF. Pulsatile index, systolic, diastolic, and mean velocity of the middle cerebral artery were measured. RESULTS: The mean age of patients with FHF was 45.4 years. One hundred percent were women, with viral hepatitis as the predominant etiology. A cerebral hypoperfusion pattern was found in 80% of the FHF group and 40% of the control group. In the former group there was no evidence of hyperemia, as there was among 20% of the control group. The mean values of velocity and pulsatile index were 36.6 cm/sec and 2.4, respectively, in the FHF group and 47.8 cm/s and 1.8 in the control group (P=0.268, P=0.402). CONCLUSIONS: FHF patients show a predominance of cerebral hypoperfusion pattern with mean velocities lower than normal values and an increased pulsatile index. We recommend that clinicians take appropriate measures to improve cerebral perfusion and avoid hypoxia. Hyperventilation as a first level measure is contraindicated.

Adult↗
PubMed2003

[Non-invasive ventilation in kyphoscoliosis. A comparison of a volumetric ventilator and a BIPAP support pressure device].

Non-invasive intermittent positive pressure ventilation (NIPPV) at home is the treatment of choice for patients with chronic respiratory insufficiency secondary to severe kyphoscoliosis. Our aim was to compare clinical course, blood gases and lung function after one month of domiciliary NIPPV with two types of ventilator and to assess sleep pattern changes in patients enrolled in a prospective, randomized crossover study. Ten patients with chronic respiratory insufficiency due to kyphoscoliosis were enrolled and randomly assigned to the first device. After one month of use, the patients underwent clinical and functional examinations and polysomnographic studies while using the ventilator. The same protocol was applied with the second device after a ten-day washout period. Baseline polysomnographs showed fragmented sleep with low percentages of deep non-REM sleep and of REM sleep, as well as respiratory patterns characterized by very high frequencies coinciding with significant desaturations. In all cases symptoms and arterial blood gas improvements were significant, with no differences between the two treatment periods. The percentages of time spent with SaO2 below 90% of reference in sleep studies were significantly lower than baseline with both ventilators. All but one patient had better tolerance of the bilevel positive airway pressure (BIPAP) support mode than of the volumetric ventilator. Our study shows that NIPPV is equally effective for patients with kyphoscoliosis whether administered with a volumetric ventilator or a BIPAP device. Subjective response and tolerance seem to be slightly better with BIPAP.

Blood Gas Analysis↗
PubMed2003

Spectroscopic study of antileishmanial drug incubated in the promastigotes of Leishmania mexicana.

In this work we present spectroscopic study of Boldine (aporphine alkaloid) that possesses important biological activities, in particular, in interaction with the promastigotes of Leishmania mexicana. The results show the applicability of autofluorescence of this drug to determinate the possible mechanism of its biological action. The blue shift and hyperchromic effect in the emission spectrum of the drug in interaction with the parasite cells indicate an energy transference process between them. The morphological change of cell shape of the promastigotes treated with the drug is observed using confocal microscopy. This morphological cell-shape transformation evidences an important interaction between the drug studied and some protein of the parasite cell. Here we describe for the first time the fluorescence properties of the Boldine in the promastigotes of L. mexicana.

Animals↗
PubMed2003

Effects of several polyhydroxylated flavonoids on the growth of B16F10 melanoma and Melan-a melanocyte cell lines: influence of the sequential oxidation state of the flavonoid skeleton.

The response of B16F10 melanoma and Melan-a melanocyte cell lines to treatment with five polyhydroxylated flavonoids and gallic acid, after 24 and 72 h of exposure, was determined, and the relationship between any antiproliferative effects observed and the chemical structure is discussed. After 24 h, none of the studied compounds showed significant cytotoxic activity in the B16F10 cell line, whereas compounds with an adjacent trihydroxylated substitution pattern did affect the viability of the Melan-a cell line. After 72 h of exposure, myricetin, baicalein and gallic acid significantly inhibited both B16F10 and Melan-a cell cultures, whereas luteolin and quercetin had only a moderate effect. Eriodictyol only had an effect on Melan-a cell viability, which was reduced slightly. These results suggest that the presence of a C2-C3 double bond and three adjacent hydroxyl groups in the flavonoid A- or B-rings confers greater antiproliferative activity to the flavonoid.

Animals↗
PubMed2003

Epidemiological study of resistance to nalidixic acid and other antibiotics in clinical Yersinia enterocolitica O:3 isolates.

Forty-six Yersinia enterocolitica O:3 clinical isolates resistant to nalidixic acid were studied. The use of molecular typing techniques, other indicators of resistance patterns, the plasmid profile, and the presence of genes that encode aminoglycoside-modifying enzyme production suggested to us a clonal dissemination of the studied strains.

Anti-Infective Agents↗
PubMed2003

Effect of montelukast added to inhaled budesonide on control of mild to moderate asthma.

BACKGROUND: Proinflammatory leukotrienes, which are not completely inhibited by inhaled corticosteroids, may contribute to asthmatic problems [corrected]. A 16 week multicentre, randomised, double blind, controlled study was undertaken to study the efficacy of adding oral montelukast, a leukotriene receptor antagonist, to a constant dose of inhaled budesonide. METHODS: A total of 639 patients aged 18-70 years with forced expiratory volume in 1 second (FEV(1)) > or =55% predicted and a minimum predefined level of asthma symptoms during a 2 week placebo run in period were randomised to receive montelukast 10 mg (n=326) or placebo (n=313) once daily for 16 weeks. All patients received a constant dose of budesonide (400-1600 microg/day) by Turbuhaler throughout the study. RESULTS: Mean FEV(1) at baseline was 81% predicted. The median percentage of asthma exacerbation days was 35% lower (3.1% v 4.8%; p=0.03) and the median percentage of asthma free days was 56% higher (66.1% v 42.3%; p=0.001) in the montelukast group than in the placebo group. Patients receiving concomitant treatment with montelukast had significantly (p<0.05) fewer nocturnal awakenings and significantly (p<0.05) greater improvements in beta agonist use and morning peak expiratory flow rate (PEFR). CONCLUSIONS: For patients with mild airway obstruction and persistent asthma symptoms despite budesonide treatment, concomitant treatment with montelukast significantly improves asthma control.

Acetates↗
PubMed2003

[Ephedrine shortens the onset of action of rocuronium but not atracurium].

HYPOTHESIS: Ephedrine increases blood flow to muscles and may shorten the onset of action of rocuronium and atracurium. MATERIAL AND METHODS: A prospective study of 80 ASA I-III patients undergoing surgery under general anesthesia and randomized to 4 groups: ephedrine-rocuronium, placebo-rocuronium, ephedrine-atracurium and placebo-atracurium. Atracurium or rocuronium was administered at a dose of 0.04 mg.Kg-1. We monitored neuromuscular function by acceleromyography, ECG and pulse oxymetry, arterial blood pressure (ABP) using an intra-arterial catheter (AT), heart rate (HR) and carbon dioxide pressure. Patient characteristics, time to onset, duration and recovery from the neuromuscular block were recorded. HR and ABP were measured at baseline, 3 minutes after ephedrine dosing, 1 minute after induction, immediately after intubation and 5, 10 and 20 minutes after intubation. RESULTS: Patient characteristics were similar in all groups. The time to onset of neuromuscular block was significantly shorter in the rocuronium and rocuronium-ephedrine groups than in the atracurium groups. Duration and recovery were similar in all groups. Patients premedicated with ephedrine experienced a significant increase in HR for 20 minutes. The only complications were 2 cases of self-limiting sinus tachycardia of less than 130 beats.min-1 in the ephedrine group. CONCLUSIONS: Premeditation with 10 mg of ephedrine decreases the time until onset of action of rocuronium but does not affect the timing of atracurium.

Adult↗
PubMed2003

[Consensus review. Pharmacological neuroprotection in cerebral ischemia: is it still a therapeutic option?].

Our increasing knowledge concerning the pathophysiology of cerebral ischemia is leading to a considerable development of drugs that at various levels block or modify the chain of biochemical processes set off as a consequence of hypoperfusion of cerebral parenchyma. In this zone of ischemic penumbra, the interaction between the neuronal ischemia cascade, the response of the glia and changes in the microcirculation, determine the evolution towards either functional recovery of the ischemic fabric or it necrosis. In various types of animal models, the majority of neuroprotective drugs have been shown to have considerable efficacy. However, this has not been translated into human clinical practice. The identification of persistence of recoverable cerebral tissue, together with the development of new designs of clinical trails better adapted to preclinical experiences and to the features of the drugs concerned, may contribute to an improved applicability of the new drugs in human clinical practice.

Animals↗
PubMed2003

[Erythropoietin alone or as an adjuvant for the autologous blood donation program in major orthopedic surgery].

BACKGROUND: Patients with anemia undergoing elective joint replacement are often excluded from preoperative autologous donation (PAD). The purpose of this study was to compare the efficacy of preoperative erythropoietin (epoetin alpha) as an adjuvant treatment to PAD versus preoperative erythropoietin alfa alone in patients with mild anemia undergoing major orthopedic surgery. PATIENTS AND METHODS: The study enrolled 75 patients scheduled for total joint arthropalsty of the hip or knee or spinal surgery and with a hemoglobin (Hb) concentration between 10 and 13 g/dL. Group 1 patients were assigned to receive weekly doses of subcutaneous epoetin alpha (40,000 IU) 21, 14, and 7 days before surgery and to participate in the PAD program; group 2 patients were excluded from the PAD program and received 2 doses of epoetin alpha every week over the same period. RESULTS: Group 1 (n = 39) and group 2 (n = 36) were similar with respect to patient characteristics, biological parameters, and surgical procedures, In group 1, mean preoperative Hb rose fom 12.5 g/dL to 12.8 g/dL, patients received a mean 5.1 doses of epoetin alpha, and they gave a mean 1.9 units of autologus blood and 1 received allogenic blood. In group 30.7% received transfusions of autologous blood and 1 received allogenic blood. In group 2, preoperative Hb increased from 11.7 g/dL to 13.5 g/dL, patients received 3.8 doses of epoetin alpha, and 3 were transfused with allogenic blood (P > 0.05). CONCLUSION: Epoetin alpha alone and erythropoietin as a adjuvant to a PAD program are equally effective in reducing allogenic transfusion during hip and knee arthroplasty and spinal column surgery of up to 3 spaces.

Aged↗
PubMed2003

[Spinal cord compression caused by hematoma related to neuroaxial anesthesia in Spain].

OBJECTIVES: Spinal cord compression from a hematoma is a rare serious complication of neuroaxial anesthesia. Our objective was to investigate cases reported and published by Spanish authors. MATERIAL AND METHODS: Cases of spinal cord compression related to neuroaxial hematomas (epidural, subarachnoid, or both) reported at congreses and meetings in Spain or published in Medline-indexed journals from 1989 through December 2002 were reviewed. The clinical characteristics, risk factors, treatments, and outcomes were described for each case. RESULTS: Since 1996, when the first cases were reported, 20 cases in all have appeared: 8 related to sub-arachnoid anesthesia, 8 to epidural anesthesia, 1 to a combination, and 1 to diagnostic lumbar puncture. In 2 cases, the neuroaxial technique used was poorly defined. Factors that might have caused the complication could be identified in 11 cases, among which there were 7 cases of anesthetic puncture or manipulation of an epidural catheter during a period of hemorrhagic risk because of antithrombotic therapy. The hematoma was evacuated surgically in 11 cases, and medical treatment was provided in 9 cases. The neurologic outcome was satisfactory in 14 cases. CONCLUSIONS: The number of compressive spinal hematomas reported or published by Spanish authors is fairly high, and there are cases related to both sub-arachnoid and epidural anesthesia. Nonsurgical treatment was provided in 45% of the cases and the outcome was satisfactory in 70%. Risk factors were identified in over half of the reported cases.

Adult↗