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J Pérez

Publications and source records attributed to J Pérez.

At least 19 recordsLinked to original sources
PubMed2006

Pathological and immunohistochemical study of gastrointestinal lesions in dolphins stranded in the Canary Islands.

This paper describes the gross, histopathological and immunohistochemical characteristics of gastrointestinal lesions and regional lymph nodes of six common dolphins (Delphinus delphis), 11 striped dolphins (Stenella coeruleoalba) and six Atlantic spotted dolphins (Stenella frontalis) found stranded along the coasts of the Canary Islands. The most common lesion was chronic granulomatous gastritis of the glandular stomach, associated with the parasite Pholeter gastrophilus, and characterised by the parasites, their eggs, or parasite debris in the mucosa, submucosa or tunica muscularis, surrounded by numerous lysozyme-positive macrophages and neutrophils, and more peripherally by abundant fibrous tissue containing variable numbers of immunoglobulin (Ig) G+ plasma cells, and small numbers of CD3+ T lymphocytes and IgM+ and IgA+ plasma cells. Anisakis simplex nematodes were found in two dolphins that were also parasitised by P gastrophilus and had parasitic granulomatous gastritis and multiple small chronic gastric ulcers. Lymphoplasmacytic enteritis was found in eight cases, three of them parasitised by Diphyllobothrium species; the lesion was characterised by moderate to severe infiltrations of CD3+ T lymphocytes and IgG+ plasma cells, with small numbers of IgM+ and IgA+ plasma cells in the lamina propria and submucosa, mainly of the small intestine. One dolphin had severe fibrinopurulent peritonitis, which may have been secondary to gastric perforation caused by the large mural granulomatous gastritis associated with P gastrophilus parasitism.

Animals↗
PubMed2006

Continuous delivery of a monoclonal antibody against Reissner's fiber into CSF reveals CSF-soluble material immunorelated to the subcommissural organ in early chick embryos.

The subcommissural organ (SCO) is an ependymal differentiation located in the dorsal midline of the caudal diencephalon under the posterior commissure. SCO cells synthesize and release glycoproteins into the cerebrospinal fluid (CSF) forming a threadlike structure known as Reissner's fiber (RF), which runs caudally along the ventricular cavities and the central canal of the spinal cord. Numerous monoclonal antibodies have been raised against bovine RF and the secretory material of the SCO. For this study, we selected the 4F7 monoclonal antibody based on its cross-reactivity with chick embryo SCO glycoproteins in vivo. E4 chick embryos were injected with 4F7 hybridoma cells or with the purified monoclonal antibody into the ventricular cavity of the optic tectum. The hybridoma cells survived, synthesized and released antibody into the CSF for at least 13 days after the injection. E5 embryos injected with 4F7 antibody displayed precipitates in the CSF comprising both the monoclonal antibody and anti-RF-positive material. Such aggregates were never observed in control embryos injected with other monoclonal antibodies used as controls. Western blot analysis of CSF from E4-E6 embryos revealed several immunoreactive bands to anti-RF (AFRU) antibody. We also found AFRU-positive material bound to the apical surface of the choroid plexus primordia in E5 embryos. These and other ultrastructural evidence suggest the existence of soluble SCO-related molecules in the CSF of early chick embryos.

Animals↗
PubMed2006

The effects of morphine self-administration on cortical pyramidal cell structure in addiction-prone lewis rats.

The consumption of drugs of abuse provokes sensitization, the development of tolerance, dependency, and eventually addiction. It is thought that these events are partially a consequence of drug-induced alterations in the organization of neuronal circuits in specific areas of the brain. In the present study, we have used intracellular injections of lucifer yellow to examine the alterations that may occur in cortical pyramidal neurons of addiction-prone Lewis rats following 15 days of self-administration of morphine. Specifically, the effects of morphine on the structure, size and branching complexity of the basal dendrites, and spine density were determined in the basal dendritic arbors of layer III pyramidal neurons in both the prelimbic and motor cortex. We found that following morphine self-administration, there was a reduction in the size and branching complexity of the dendritic arbors of pyramidal cells in the motor cortex. In contrast, prelimbic pyramidal neurons from these morphine-treated animals had larger and longer basal dendritic arbors. Furthermore, the spine density on pyramidal neurons was higher in both cortical regions of morphine self-administered rats. These results suggest that at least part of the behavioral changes produced by repeated opiate administration may be attributed to alterations in pyramidal cell structure.

Analgesics, Opioid↗
PubMed2006

Fronts with continuous waiting-time distributions: theory and application to virus infections.

We generalize to arbitrary waiting-time distributions some results which were previously derived for discrete distributions. We show that for any two waiting-time distributions with the same mean delay time, that with higher dispersion will lead to a faster front. Experimental data on the speed of virus infections in a plaque are correctly explained by the theoretical predictions using a Gaussian delay-time distribution, which is more realistic for this system than the Dirac delta distribution considered previously [J. Fort and V. Méndez, Phys. Rev. Lett. 89, 178101 (2002)].

Animals↗
PubMed2006

Basiliximab: a comparative study between the use of the recommended two doses versus a single dose in living donor kidney transplantation.

Basiliximab (Simulect) is a high-affinity chimeric and humanized monoclonal antibody, directed against the alpha chain of human interleukin-2 receptor (CD25). The administration of two doses (20 mg intravenously per dose), one given 2 hours before transplantation and the second on day 4 posttransplant, provides suppression of the interleukin-2 receptor for up to 45 days, reducing the rate of acute rejection in kidney transplantation. This study was designed to compare the efficacy of a single dose of Simulect to the recommended two doses. The other objective was the reduction of the costs related to the standard two dose protocol. Fifty-two patients were included: group I (32 patients) received two doses of Simulect; group II (20 patients) received one dose. There were 39 living related donors and 13 living unrelated. All patients were followed for 1 year. Maintenance immunosuppression consisted of tacrolimus or cyclosporine, mycophenolate mofetil, and steroids. The diagnosis of rejection was made clinically. All episodes were treated with intravenous steroids. The incidence of rejection was similar in both groups; there was no graft loss to rejection. There were two deaths in group I, and one death in group II, yielding graft and patient actual survival rates at 1 year of 93% and 95%, respectively. These results suggest that Simulect is equally effective when administered in two doses or in a single dose in kidney transplantation. The reduction of cost by giving a single dose is significant, especially in developing countries without national health insurance.

Adult↗
PubMed2006

Biodegradation of high 4-chlorophenol concentrations in a discontinuous reactor fed with an optimally controlled influent flow rate.

This work presents the results of the application of an optimally controlled influent flow rate strategy to biodegrade, in a discontinuous reactor, high concentrations of 4-chlorophenol used as toxic compound model. The influent is fed into the reactor in such a way as to obtain the maximal degradation rate, thus avoiding the inhibition of the microorganisms. The optimal strategy was able to manage increments of toxic concentrations in the influent up to 7,000 mg 4CP/L without any problem. It was shown not only that higher concentrations of toxic could be treated, but also that a reduction in degradation time (around 52%) and in the supplied air volume was obtained.

Bacteria, Anaerobic↗
PubMed2005

Bayesian methods for the conformational classification of eight-membered rings.

Two methods for the classification of eight-membered rings based on a Bayesian analysis are presented. The two methods share the same probabilistic model for the measurement of torsion angles, but while the first method uses the canonical forms of cyclooctane and, given an empirical sequence of eight torsion angles, yields the probability that the associated structure corresponds to each of the ten canonical conformations, the second method does not assume previous knowledge of existing conformations and yields a clustering classification of a data set, allowing new conformations to be detected. Both methods have been tested using the conformational classification of Csp3 eight-membered rings described in the literature. The methods have also been employed to classify the solid-state conformation in Csp3 eight-membered rings using data retrieved from an updated version of the Cambridge Structural Database (CSD).

Algorithms↗
PubMed2005

Divalent ion-dependent swelling of tomato bushy stunt virus: a multi-approach study.

Time-resolved small-angle X-ray and neutron scattering (SAXS and SANS) in solution were used to study the swelling reaction of TBSV upon chelation of its constituent calcium at mildly basic pH. SAXS intensities comprise contribution from the protein capsid and the RNA moiety, while neutron scattering, recorded in 72% D2O, is essentially due to the protein capsid. Cryo-electron micrographs of compact and swollen virus were used to produce 3D reconstructions of the initial and final conformations of the virus at a resolution of 13 A and 19 A, respectively. While compact particles appear to be very homogeneous in size, solutions of swollen particles exhibit some size heterogeneity. A procedure has been developed to compute the SAXS pattern from the 3D reconstruction for comparison with experimental data. Cryo-electron microscopy thereby provides an invaluable starting (and ending) point for the analysis of the time-resolved swelling process using the scattering data.

Cations, Divalent↗
PubMed2005

Skin immune responses in cattle after primary and secondary infections with Hypoderma lineatum (Diptera: Oestridae) larvae.

Cellular immune responses were examined in the skin of cattle after primary and secondary experimental infections with Hypoderma lineatum larvae. Skin biopsies were taken at 0, 6, 12, 48 and 96 h post-infection (h.p.i.). In primary infected animals the penetration of Hypoderma larvae was characterized by moderate inflammatory responses. The pattern of cellular changes in previously infected animals suggested an allergic or rheumatic process, probably as a consequence of the development of a type III hypersensitivity reaction against the second or successive reinfections. Perivascular infiltration with CD3(+) T lymphocytes was marked in infected groups, but especially in previously infected animals, with a significant increase with respect to uninfected controls at 48 h.p.i. B cells remained close to control values during primary infection, while they increased significantly 12 h.p.i. in reinfected animals. IgG(+) plasma cells were also very abundant during secondary infections, with significant differences from primary infected and uninfected animals from 6 h.p.i. onwards. These results suggest that secondary infections allow cellular responses which may be effective in killing some of the entering larvae, resulting in a degree of resistance.

Animals↗
PubMed2005

Reissner's fiber formation depends on developmentally regulated factors extrinsic to the subcommissural organ.

Reissner's fiber (RF) is a threadlike structure present in the third and fourth ventricles and in the central canal of the spinal cord. RF develops by the assembly of glycoproteins released into the cerebrospinal fluid (CSF) by the subcommissural organ (SCO). SCO cells differentiate early during embryonic development. In chick embryos, the release into the CSF starts at embryonic day 7 (E7). However, RF does not form until E11, suggesting that a factor other than release is required for RF formation. The aim of the present investigation was to establish whether the factor(s) triggering RF formation is (are) intrinsic or extrinsic to the SCO itself. For this purpose, SCO explants from E13 chick embryos (a stage at which RF has formed) were grafted at two different developmental stages. After grafting, host embryos were allowed to survive for 6-7 days, reaching E 9 (group 1) and E13 (group 2). In experimental group 1, the secretion released by the grafted SCOs never formed a RF; instead, it aggregated as a flocculent material. In experimental group 2, grafted SCO explants were able to develop an RF-like structure, similar to a control RF. These results suggest that the factor triggering RF formation is not present in the SCO itself, since E13 SCO secretion forms an RF in E13 brains but never develops RF-like structures when placed in earlier developmental environments. Furthermore, the glycoproteins released by implanted SCOs bind specifically to several structures: the apical portion of the mesencephalic floor plate and the choroid plexus of the third and fourth ventricles.

Animals↗
PubMed2005

Experimental analysis and modified rotor description of the infrared fundamental band of HCl in Ar, Kr, and Xe solutions.

We report an experimental study of the rotovibrational fundamental PQR-band shapes in the IR absorption spectra of HCl dissolved in condensed rare gases in a wide range of temperatures. The effective vibrational frequencies are determined from analysis of the fine rotational structure partially resolved in the band wings. The central Q-branch components appear redshifted with respect to the effective vibrational frequencies, their shifts in different solvents found to match the HCl stretching mode shifts in binary Rg...HCl van der Waals heterodimers. Theoretical quasi-free rotor and modified rotor models are applied to describe evolution of the band profiles at changing thermodynamic conditions. Both models are shown to reproduce equally well the observed spectral density distributions in the band wings. However, the modified rotor formalism that accounts for depopulation of the lower-energy rotational solute states provides better agreement with the experiment in the range of the P- and R-branch maxima. We surmise that the Q branches separated from the measured spectral profiles are formed by transitions between rotationally hindered states of diatomic molecules coupled to the solvent by the local anisotropy of the interaction potential.

Journal Article↗
PubMed2005

[Primary hyperhidrosis and anxiety: a prospective preoperative survey of 158 patients].

OBJECTIVE: To determine the location of hyperhidrosis, the accompanying signs and symptoms, and patient anxiety assessed on 2 scales and standardized psychometric instruments. PATIENTS AND METHODS: A prospective study of patients with hyperhidrosis was carried out between September 1, 2001 and June 30, 2003 with a self-administered preoperative questionnaire. The variables studied included the location of hyperhidrosis, the accompanying signs and symptoms, and the self-reported degree of anxiety and perception of its effect on daily life assessed by the State-Trait Anxiety Inventory (STAI) and a questionnaire designed in our department. RESULTS: Palmar hyperhidrosis was reported by 93.6% of patients, plantar by 70.2%, axillary by 66.4%, facial by 12.1%, groin by 8.2%, chest by 5%, and abdominal by 2%. While more than 50% of the patients reported facial blushing and palpitations as accompanying signs and symptoms, approximately 30% experienced epigastric pain, trembling, and headaches. Over half of the patients reported that their anxiety was incapacitating, and a mere 1.2% experienced none at all. STAI scores were similar to those of the general population whereas scores on our department's questionnaire reflected those of the self-reported anxiety ratings. CONCLUSIONS: Primary hyperhidrosis is a disorder in which excessive sweating occurs mainly, but not exclusively, on the palms. The condition is accompanied by signs and symptoms typical of autonomic nervous system hyperactivity and by a degree of anxiety that has an incapacitating effect on normal life, although that anxiety is not detected by the STAI questionnaire alone.

Adolescent↗
PubMed2005

Assessment by cytogenetic analysis of the radioprotection properties of propolis extract.

Propolis obtained from honeybee hives has been used in folk medicine as an anti-inflammatory, anti-carcinogenic or immunomodulatory agent. In animal studies, the radioprotector effect of propolis has been attributed to its free-radical scavenging properties. The present study was carried out to show the protective properties of propolis extract against DNA damage induced by gamma irradiation. The evaluation of the radioprotective effect of propolis has been carried out by the analysis of chromosome aberration induction after several doses of gamma rays. The results of an analysis in the presence of ethanol extract of propolis (EEP) were compared with the dose-effect calibration curve for gamma-rays by analysis of chromosome aberrations without propolis, a decrease in the radiation-induced chromosome aberrations has been observed to be higher than 50% for all the doses.

Cells, Cultured↗
PubMed2005

[Study of immutable variables determining rHuEPO dose requirements on hemodialysis patients].

Patients receiving recombinant human erythropoietin (rHuEPO) therapy show wide variability in their responsiveness to the drug. Variables that affect rHuEPO dose requirements can be broadly divided into modificable and immutable characteristics. Most of the scientific research on rHuEPO hyporesponsiveness has focused on modificable variables (iron status, dialysis adequacy), while immutable variables such as gender, etiology of chronic renal failure (CRF) and age have been insufficiently explored. A cross sectional study was performed in order to evaluate if immutable patient characteristics determine rHuEPO dose requirements among 215 patients (52% males; mean age 66 +/- 14 years) on hemodialysis (HD) for more than twelve months. Data were collected at 10 hemodialysis units in Aragon. Patients were divided into three groups according to their gender, their cause of CRF (diabetic nephropathy, vascular nephropathy, tubulointerstitial nephropathy and primary glomerulonephritis) and their age (younger than 60 years, from 60 to 75 years, older than 75 years). Despite a similar dose of rHuEPO, women had lower mean hemoglobin (11.1 +/- 1.5 versus 11.6 +/- 1.7 g/dl; p = 0.0258) than men. The greater hemoglobin in men than women may be attributed to greater serum albumin in men (3.5 +/- 0.3 versus 3.7 +/- 0.3 mg/dl; p = 0.0001). Requirements of rHuEPO were higher in the patients with etiology of primary glomerulonephritis compared with those with the other etiologies, even those with diabetic nephropathy (p = 0.0374). The rHuE-PO doses required to obtain similar hemoglobin levels were higher in patients younger than 60 years (p = 0.0249). We conclude that women, patients with primary glomerulonephritis as cause of CRF, and patients younger than 60 years showed the highest requirements of rHuEPO doses.

Aged↗
PubMed2004

The MELISSA pilot plant facility as as integration test-bed for advanced life support systems.

The different advances in the Micro Ecological Life Support System Alternative project (MELISSA), fostered and coordinated by the European Space Agency, as well as in other associated technologies, are integrated and demonstrated in the MELISSA Pilot Plant laboratory. During the first period of operation, the definition of the different compartments at an individual basis has been achieved, and the complete facility is being re-designed to face a new period of integration of all these compartments. The final objective is to demonstrate the potentiality of biological systems such as MELISSA as life support systems. The facility will also serve as a test bed to study the robustness and stability of the continuous operation of a complex biological system. This includes testing of the associated instrumentation and control for a safe operation, characterization of the chemical and microbial safety of the system, as well as tracking the genetic stability of the microbial strains used. The new period is envisaged as a contribution to the further development of more complete biological life support systems for long-term manned missions, that should be better defined from the knowledge to be gained from this integration phase. This contribution summarizes the current status of the Pilot Plant and the planned steps for the new period.

Biodegradation, Environmental↗
PubMed2004

In-hospital and 2-year survival of patients treated with mechanical ventilation for acute exacerbation of COPD.

OBJECTIVE: To analyze in-hospital and 2-year survival of patients who require mechanical ventilation with intubation after acute respiratory failure due to exacerbation of chronic obstructive pulmonary disease (COPD). The secondary objective was to identify the prognostic factors for in-hospital mortality and mortality at 2 years. PATIENTS AND METHODS: We retrospectively studied 101 patients with suspected COPD admitted to the intensive care unit between July 1993 and December 1998. Variables potentially related to mortality were analyzed with a univariate model and by logistic regression. RESULTS: In-hospital survival was 74.3% and 2-year survival was 55.4%. Survival at 2 years was 81% for patients discharged from hospital. The variables associated with in-hospital mortality were age greater than 65 years, electrocardiographic diagnosis of chronic cor pulmonale, and development of multiorgan dysfunction syndrome. No factors predictive of mortality at 2 years were identified. CONCLUSIONS: The in-hospital survival rate for patients with an acute exacerbation of COPD who require mechanical ventilation is good and the 2-year survival rate is acceptable. Age, electrocardiographic signs of cor pulmonale, and development of multiorgan dysfunction syndrome were associated with greater risk of in-hospital mortality.

Acute Disease↗
PubMed2004

[Compensatory sweating after upper thoracic sympathectomy. Prospective study of 123 cases].

OBJECTIVE: The most unpleasant consequence of upper thoracic sympathectomy is compensatory sweating (CS). De-pending on the series, the incidence of CS ranges from 24% to 85%. The aim of this study was to determine the relation between CS and the following factors: distribution of hyperhidrosis, procedure performed (unilateral, synchronic bilateral, or sequential bilateral), and number of sympathetic ganglia eliminated. In addition, the degree of patient satisfaction was recorded as objectively as possible. PATIENTS AND METHODS: Prospective study of 123 patients who underwent upper thoracic sympathectomy for palmar and/or axillary hyperhidrosis between 1 January, 1996 and 1 June, 2002 at our unit. All patients completed a questionnaire on symptoms 8 weeks before and after surgery to deter-mine postoperative changes in distribution of the hyperhidrosis and the overall degree of satisfaction on a scale of 0 to 4. RESULTS: The sensation of CS was reported by 86.1% of the patients. When asked to relate this sensation to changes in sweating intensity in specific parts of the body, 46.54% reported CS and 48.37% no change. The trunk was the only region where statistically significant increases in CS occurred; in the feet, a decrease in sweating was noted. No differences in CS were observed with respect to the type of surgery or the number of sympathetic ganglia eliminated. The overall results were considered very satisfactory or quite satisfactory by 84.55% of the patients, while 4.88% were very dissatisfied. CONCLUSIONS: Although CS is a side effect of upper thoracic sympathectomy, not all patients are affected by it. Significant CS occurs mainly in the back, chest, and abdomen. Neither the type of intervention nor the number of ganglia eliminated has an effect on CS. This side effect notwithstanding, overall satisfaction with the treatment is very satisfactory given that the palmar hyperhidrosis is eliminated.

Adolescent↗