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J Castillo

Publications and source records attributed to J Castillo.

At least 91 records · Page 5Linked to original sources
PubMed2001

Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV.

We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.

Journal Article↗
PubMed2001

T7 displayed peptides as targets for selecting peptide specific scFvs from M13 scFv display libraries.

M13 scFv display libraries are frontline research tools due to the rapidity in which target binding scFv can be obtained. Simple modifications of the standard affinity selection and amplification protocol allow for multiple targets to be panned simultaneously. Target peptide or protein production can become the rate-limiting step in a high throughput approach to antibody selection. To overcome this obstacle and to save both time and money, we have displayed the target peptides on T7 phage particles. In this paper we demonstrate that these particles can be used directly to select peptide specific scFv. We have discovered that the selection is most efficient when a linker separates the display from the T7 coat protein and when a continuous subtraction is employed. We have used antibodies selected in this fashion to characterize target proteins in cell lysates, immuno-precipitations and immuno-histochemistry.

Antibody Specificity↗
PubMed2001

Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV.

The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. The multiplicity density at midrapidity for the 5% most central interactions is dN(h(-))/d(eta)/(eta = 0) = 280+/-1(stat)+/-20(syst), an increase per participant of 38% relative to pp collisions at the same energy. The mean transverse momentum is 0.508+/-0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h(-) yield per participant is a strong function of p( perpendicular). The pseudorapidity distribution is almost constant within /eta/<1.

Journal Article↗
PubMed2001

Pion Interferometry of square root of (s(NN)) =130 GeV Au + Au collisions at RHIC.

Two-pion correlation functions in Au+Au collisions at square root of [s(NN)] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in square root of [s(NN)].

Journal Article↗
PubMed2001

Midrapidity antiproton-to-proton ratio from Au+Au collisions at sqrt [s(NN)]=130 GeV.

We report results on the ratio of midrapidity antiproton-to-proton yields in Au+Au collisions at sqrt[s(NN)] = 130 GeV per nucleon pair as measured by the STAR experiment at RHIC. Within the rapidity and transverse momentum range of /y/<0.5 and 0.4<p(t)<1.0 GeV/c, the ratio is essentially independent of either transverse momentum or rapidity, with an average of 0.65+/-0.01((stat))+/-0.07((syst)) for minimum bias collisions. Within errors, no strong centrality dependence is observed. The results indicate that at this RHIC energy, although the p-p pair production becomes important at midrapidity, a significant excess of baryons over antibaryons is still present.

Journal Article↗
PubMed2001

Non-toxic pyrrolizidine alkaloids from Eupatorium semialatum.

The leaves of Eupatorium semialatum were investigated for the occurrence of pyrrolizidine alkaloids. Although this type of alkaloids generally occurs in the Eupatorieae, only unusual non-toxic pyrrolizidines of the tussilagin type were identified. All compounds are methyl esters of the corresponding beta-amino acids.

Journal Article↗
PubMed2001

Elliptic flow in Au+Au collisions at square root(S)NN = 130 GeV.

Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented.

Journal Article↗
PubMed2001

Epidemiology of chronic daily headache.

Daily or near-daily headache is a widespread problem in clinical practice. The general term of chronic daily headache (CDH) encompasses those primary headaches presenting more than 15 days per month and lasting more than 4 hours per day. CDH includes transformed migraine (TM), chronic tension-type headache (CTTH), new daily persistent headache (NDPH), and hemicrania continua (HC). Around 40% of patients attending a specialized headache clinic meet CDH diagnostic criteria, of which 80% are women. In these clinics about 60% of patients suffer from TM, 20% from CTTH, and 20% meet NDPH criteria. Most, some 80%, overuse symptomatic medications. One should be very cautious on extrapolating these numbers to the general population. CDH prevalence in the general population seems to be around 4% to 5% (up to 8% to 9% for women). Regarding the prevalence of CDH subtypes, NDPH is rare (0.1%), whereas the prevalence of TM (1.5% to 2%) and CTTH (2.5% to 3%) is clearly higher. In contrast to data from specialized clinics, only around a quarter of CDH subjects in the general population overuse analgesics; the prevalence of CDH subjects with analgesic overuse being 1.1% to 1.9% of the general population. Most of these patients with analgesic overuse are TM patients.

Analgesics↗
PubMed2001

Improved water solubility of neohesperidin dihydrochalcone in sweetener blends.

Significant technological advantages in terms of sweetness synergy and hence cost-saving can be obtained if neohesperidin dihydrochalcone (NHDC) is used in sweetener blends with other intense or bulk sweeteners. The combination of NHDC with sodium saccharin or sodium cyclamate is an excellent method to improve the water solubility at room temperature of NHDC. In the case of NHDC-sodium saccharin, two different methods for blend preparation, a simple mixture and a cosolubilized mixture, can be used, with similar results obtained for solubility and solution stability properties. To improve temporally the water solubility of NHDC in combination with sodium cyclamate, it is absolutely necessary to prepare cosolubilized blends.

Chalcone↗
PubMed2001

Neuroprotective effect of aspirin by inhibition of glutamate release after permanent focal cerebral ischaemia in rats.

Aspirin reduces the size of infarcts after ischaemic stroke. Although this fact has been attributed to its anti-platelet actions, direct neuroprotective effects have also been reported. We have recently demonstrated that aspirin is neuroprotective by inhibiting glutamate release in 'in vitro' models of brain ischaemia, via an increase in ATP production. The present study was designed to determine whether the inhibition of glutamate release induced by aspirin might be protective in a whole-animal model of permanent focal brain ischaemia. Focal brain ischaemia was produced in male adult Fischer rats by occluding both the common carotid and middle cerebral arteries. Central and serum glutamate levels were determined at fixed intervals after occlusion. The animals were then killed and infarct volume was measured. Aspirin (30 mg/kg i.p. administered 2 h before the occlusion) produced a significant reduction in infarct volume, an effect that correlated with the inhibition caused by aspirin on ischaemia-induced increase in brain and serum glutamate concentrations after the onset of the ischaemia. Aspirin also inhibited ischaemia-induced decrease in brain ATP levels. Our present findings show a novel mechanism for the neuroprotective effects of aspirin, which takes place at concentrations in the anti-aggregant-analgesic range, useful in the management of patients with risk of ischaemic events.

Adenosine Triphosphate↗
PubMed2001

Carotid endarterectomy in female patients: are the concerns of the Asymptomatic Carotid Atherosclerosis Study valid?

OBJECTIVES: Although the results of the Asymptomatic Carotid Atherosclerosis Study clearly demonstrated the benefit of surgical over medical management of severe carotid artery stenosis, the results for women in particular were less certain. This was to some extent because of the higher perioperative complication rate observed in the 281 women (3.6% vs 1.7% in men). The objective of this study was to review a large experience with carotid endarterectomy in female patients and to determine whether the perioperative results differed from those of male patients. METHODS: A review was conducted of a prospectively compiled database on all carotid endarterectomies performed between 1982 and 1997. Operations performed in 991 female patients were compared with those performed in 1485 male patients. RESULTS: Female patients had a significantly lower incidence of diabetes, coronary artery disease, and contralateral carotid artery occlusion than did male patients. Female patients had a significantly higher incidence of hypertension. There were no significant differences in the age, smoking history, anesthetic route, shunt use, or clamp tolerance between the two groups. Of 991 female patients, 659 (66.5%) had preoperative symptoms, whereas 332 (33.5%) cases were performed for asymptomatic stenosis. Among 1485 male patients, 1041 (70.1%) had symptoms, and 444 (29.9%) were symptom free before surgery. There were no significant differences noted in the perioperative stroke rates between men and women overall (2.3% vs 2.4%, P =.92), or when divided into symptomatic (2.5% vs 3.0%, P =.52) and asymptomatic (2.0% vs 1.2%, P =.55) cases. CONCLUSIONS: Carotid endarterectomy can be performed with equally low perioperative stroke rates in men and women in both symptomatic and asymptomatic cases. In this series, symptom-free female patients had the lowest overall stroke rate. The concerns of the Asymptomatic Carotid Atherosclerosis Study regarding the benefit of carotid endarterectomy in female patients should therefore not prevent clinicians from recommending and performing carotid endarterectomy in appropriately selected symptom-free female patients.

Aged↗
PubMed2001

Predictors of deteriorating cerebral infarct: role of inflammatory mechanisms. Would its early treatment be useful?

The development of neurological deterioration in the hours following the stroke onset occurs in somewhat more than 1 in 3 cerebral infarcts and is associated with an increase in morbidity and mortality. This early deterioration (0--48/72 h) entails the conversion of the ischemic penumbra area in an irreversible lesion, a process that is mediated as much by hemodynamic changes in the local cerebral circulation as by biochemical mechanisms. Late neurological deterioration (3--7 days) is more frequently associated with systemic causes. Knowledge of the various clinical, biochemical and imaging markers associated with neurological deterioration is consequently of fundamental importance. For their repercussion in clinical practice, we classify these predictors of deteriorating cerebral infarct into nonmodifiable, modifiable and possibly modifiable. The reduction in cerebral blood flow in a particular cerebral zone causes very early cerebral damage as a consequence of a significant liberation of neuroexcitatory amino acids, followed by an excessive entry of calcium into the interior of cells; this process causes lipid peroxidation, disintegration of the cellular membranes, nuclear destruction and neuronal death. Moreover, ischemia and posterior reperfusion induce an inflammatory response leading to further cellular destruction. It is therefore conceivable that therapeutic interventions aimed at decreasing proinflammatory cytokines and cell adhesion molecules might result in better outcome in this population.

Cerebral Infarction↗
PubMed2001

Neurological deterioration in acute lacunar infarctions: the role of excitatory and inhibitory neurotransmitters.

BACKGROUND AND PURPOSE: The mechanisms involved in the neurological deterioration of acute lacunar strokes are unknown. Although accumulating evidence suggests that glutamate release plays a role in the progression of territorial infarctions, it remains to be established whether excitotoxicity also participates in lacunar stroke progression. We investigated whether excitatory and inhibitory amino acid concentrations in blood predict subsequent progressive motor deficits in lacunar infarctions. METHODS: We studied 113 consecutive patients with lacunar infarct, defined by clinical and computed tomography/magnetic resonance imaging criteria, within the first 24 hours after stroke onset. Neurological deterioration was defined as a decrease of >/=1 points in the motor items of the Canadian Stroke Scale in the first 48 hours after admission. Glutamate, glycine, and GABA were determined by high-performance liquid chromatography in plasma samples obtained on admission. Predictive values, sensitivity, specificity, and accuracy of specific glutamate and GABA concentrations and glutamatexglycine/GABA index for progression of lacunar stroke were calculated. RESULTS: Twenty-seven patients (23.9%) had neurological worsening. Plasma concentrations of glutamate (253+/-70 versus 123+/-73 micromol/L, mean+/-SD) were higher and those of GABA (140+/-63 versus 411+/-97 nmol/L) were lower in the progressing group than in the nonprogressing group (both P<0.001). Glutamate concentrations >200 micromol/L and GABA levels <240 nmol/L had a positive predictive value for neurological deterioration of 67% and 84%, respectively. A excitotoxic index >106 had a positive predictive value of 85%. CONCLUSIONS: These findings suggest that an imbalance between the glutamate and GABA concentrations may play a role in the pathophysiology of progressing lacunar infarctions.

Acute Disease↗
PubMed2001

Identification of a type II insulin-like growth factor receptor in fish embryos.

To determine whether fish have an insulin-like growth factor II/mannose 6-phosphate (IGF-II/M6-P) receptor similar to that of mammals, we have performed binding, cross-linking, and immunoprecipitation experiments with wheat-germ-agglutinin- and mannose 6-phosphate (M6-P)-affinity-purified receptor preparations from fish embryos. In both receptor preparations, IGF-II binding was specific, because labeled IGF-II could only be completely displaced by cold IGF-II but not by IGF-I or insulin. Labeled IGF-II bound to a protein with a molecular mass of approximately 250 kDa, which could be immunoprecipitated with an antibody against the rat IGF-II receptor. IGF-II stimulated tyrosine kinase activity in wheat germ agglutinin preparations and was more potent than insulin or IGF-I, but neither peptide stimulated tyrosine kinase activity in M6-P preparations. Two fish cell lines (CHSE-214 and EPC) were used to confirm the IGF-II binding data obtained in the receptor preparations, revealing the presence of highly specific IGF-II binding and the absence of insulin binding. Furthermore, a decrease of the IGF-I receptors on the cell surface did not alter IGF-II binding in EPC cells. In conclusion, we have detected the presence of IGF-II/M6-P receptors in fish embryos that are similar in structure and specificity for their ligand to those found in mammals.

Animals↗
PubMed2001

Liver transplantation in a case of steatohepatitis and subacute hepatic failure after biliopancreatic diversion for morbid obesity.

BACKGROUND: Biliopancreatic diversion (BPD) was designed to avoid the serious complications of jejunoileal bypass (steatohepatitis and hepatic failure). Although this is today considered a safe and effective procedure, a few reports of patients who developed steatohepatitis and subsequently died in hepatic failure exist. METHODS: We report a morbidity obese patient who developed subacute hepatitis resulting in hepatic failure 1 year after BPD. RESULTS: Because of irreversible liver failure the decision to perform a liver transplantation was made. The patient underwent emergency liver transplant and lengthening of the common limb. The course of liver transplantation and the patient's recovery were uneventful. CONCLUSION: Severe liver disease may rarely follow BPD. Liver transplantation and lengthening of the common bowel may be performed to treat these patients.

Adult↗
PubMed2001

[Personality changes in chronic daily headache: a study in the general population].

BACKGROUND AND AIMS: The prevalence and type of personality disorders in unselected patients with chronic daily headache (CDH) are unknown. The aim of this study was to analyze the personality profile of patients with CHD is the general population. PATIENTS AND METHODS: Eighty-nine patients with CDH taken from a sample of 1,883 unselected subjects from the general population completed the EPQ-A (Eysenck Personality Questionnaire-Adult). RESULTS: Sixty percent of the patients with CDH presented a personality profile with high values in the scales measuring both the neurotic component (N scales) and the psychotic component (P scale). No significant differences were observed in the percentage of patients with high scores in these scales according to the diagnoses of transformed migraine (TM) or chronic tension headache (CTH). However, the percentage of questionnaires with high or not adapted scores was significantly greater in the patients abusing of analgesic drugs than is the non-abusers (82% versus 53%). With regard to the personality profile, we found a greater, but not significant, percentage of patients with CDH with a high grade of neuroticism in comparison with psychoticism (52% versus 36%). There were no significant differences in the personality profile between the two main subgroups of CCH, TM and CTC: 56% of the patients with TM showed high grade of neuroticism and 47% psychoticism versus 52% and 30%, respectively in the case of the patients with CTC. Sixty-eight percent of the analgesic abusers presented neurotic features and 50% psychotic features versus 47% and 32%, respectively, for the non abusers. CONCLUSIONS: There is a high percentage of subjects with CDH in the general population who present high scores in the scales measuring the two basic components of the personality, such as neuroticism and psychoticism. This personality profile is still found more frequently in patients presenting symptomatic medication abuse.

Adult↗