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J Flores

Publications and source records attributed to J Flores.

At least 37 records · Page 2Linked to original sources
PubMed2002

Induction of angiotensin converting enzyme in neointima after intravascular stent placement.

BACKGROUND: To investigate the morphological changes of the arterial wall and the expression of angiotensin converting enzyme (ACE) in the arterial wall after stent placement in a canine model. METHODS: Seventeen mongrel dogs underwent stent placement (Gianturco's Z stent) in the aorta. Six animals were sacrificed at 4 weeks after stent implantation, and the other 5 animals at 12 weeks. The normal aorta was harvested from 6 dogs. The specimens were stained with hematoxylin-eosin (H&E) as well as by immunohistochemistry (smooth muscle specific a-actin, and ACE). Histomorphometric analysis was performed using the sections stained with H&E and smooth muscle specific a-actin. RESULTS: The total intimal area was significantly increased at all time points as compared with the control aorta. The a-actin positive intimal area was also significantly increased at all time points as compared with the control aorta. In the control aorta, luminal endothelial cells as well as a-actin positive medial cells occasionally exhibited faint cytoplasmic staining for ACE. In the 4- and 12-week stented aorta, a-actin positive cells in the neointima and media as well as macrophages in the adventitia stained strongly positive for ACE. CONCLUSIONS: ACE was induced in the neointima after stent placement of the canine aorta. Considering its multiple biological actions, ACE may be associated with the pathogenesis of neointimal hyperplasia after stent placement.

Actins↗
PubMed2002

Bioavailability of ranitidine in healthy Mexican volunteers: effect of food.

Is well known that food can affect the bioavailability of several drugs, its impact is major for those drugs that have to act near of drug absorption. Documentation about alterations of ranitidine bioavailability by effect of food is poor. The purpose of this work was to evaluate the effect of food over the bioavailability of ranitidine. Twenty healthy Mexican volunteers were included for the study. The study was made in two stages, in the first one the volunteers had 12 hour fast and took a 300 mg of oral dose of ranitidine (without food, WOF) and blood samples were drawn. Two weeks later, the volunteers took a normal diet just before ranitidine intake (with food, WF). The area under the curve (AUC) was 30% greater in WOF, Cmax was 921.5 ng/ml (WF) vs. 1685.2 (WOF), and t1/2 was 2.70 +/- 1.38 (WF) h vs 3.66 +/- 1.34 (WOF). The AUC, Cmax and t1/2 were statistically different. It is evident that there are differences in the drug disposition due to the presence of food, then, it is possible that the efficacy of ranitidine as inhibitor of gastric secretion being limited by food.

Adolescent↗
PubMed2001

Safety and immunogenicity of a canarypox-vectored human immunodeficiency virus Type 1 vaccine with or without gp120: a phase 2 study in higher- and lower-risk volunteers.

Live attenuated viral vectors that express human immunodeficiency virus (HIV) antigens are being developed as potential vaccines to prevent HIV infection. The first phase 2 trial with a canarypox vector (vCP205, which expresses gp120, p55, and protease) was conducted in 435 volunteers with and without gp120 boosting, to expand the safety database and to compare the immunogenicity of the vector in volunteers who were at higher risk with that in volunteers at lower risk for HIV infection. Neutralizing antibodies to the MN strain were stimulated in 94% of volunteers given vCP205 plus gp120 and in 56% of volunteers given vCP205 alone. CD8(+) cytotoxic T lymphocyte cells developed at some time point in 33% of volunteers given vCP205, with or without gp120. Phase 3 field trials with these or similar vaccines are needed, to determine whether efficacy in preventing HIV infection or in slowing disease progression among vaccinees who become infected is associated with the level and types of immune responses that were induced by the vaccines in this study.

AIDS Vaccines↗
PubMed2001

Spectral statistics of the two-body random ensemble revisited.

Using longer spectra we reanalyze spectral properties of the two-body random ensemble studied 30 years ago. At the center of the spectra the old results are largely confirmed, and we show that the nonergodicity is essentially due to the variance of the lowest moments of the spectra. The longer spectra allow us to test and reach the limits of validity of French's correction for the number variance. At the edge of the spectra we discuss the problems of unfolding in more detail. With a Gaussian unfolding of each spectrum the nearest-neighbor spacing distribution between ground state and first exited state is shown to be stable. Using such an unfolding the distribution tends toward a semi-Poisson distribution for longer spectra. For comparison with the nuclear table ensemble we could use such unfolding obtaining similar results as in the early papers, but an ensemble with realistic splitting gives reasonable results if we just normalize the spacings in accordance with the procedure used for the data.

Journal Article↗
PubMed2001

Severe respiratory failure secondary to Cushing's myopathy.

We report a 55-year-old woman with typical clinical, biochemical and radiological features of Cushing's disease, who developed a severe respiratory insufficiency as the main symptom. She also complained of proximal muscle weakness over the last year and progressive dyspnea over the last four months. Bronchospasm, respiratory infection or cardiologic dysfunction were excluded. Arterial blood gas analysis showed severe respiratory insufficiency with hypoxemia and hypercapnia, respiratory acidosis and a normal alveolar-arterial oxygen gradient. Spirometry and plethysmography showed a restrictive ventilatory failure and maximum inspiratory and expiratory pressures were reduced. These findings were strongly suggestive of neuromuscular disease. Serum creatine kinase, aldolase, sodium, potassium and thyroid function tests were normal. An electromyogram and a muscle biopsy confirmed myopathic disease. Ketoconazole therapy improved her symptoms and respiratory function tests. In conclusion although proximal myopathy is a frequent presenting symptom of Cushing's syndrome, involvement of respiratory muscles with severe restrictive ventilatory dysfunction has not been previously reported as the main initial feature of Cushing's disease. Medical treatment of hypercortisolism improves muscle strength and resolves the respiratory insufficiency.

Cushing Syndrome↗
PubMed2001

Progress in HIV vaccine development.

Recent advances in HIV vaccine development include initiation of the first efficacy trials and substantial expansion of the preclinical pipeline. Several preclinical candidate vaccines have induced strong cellular immune responses and provided impressive protection against AIDS in non-human primate models; however, candidates that induce broadly neutralizing antibodies remain elusive.

AIDS Vaccines↗
PubMed2001

Bereavement coping self-efficacy in cancer widows.

This study applied social cognitive theory to help explain the differential outcomes observed in conjugal bereavement. Specifically, a measure of bereavement coping self-efficacy was created and relationships tested with psychological, spiritual, and physical health outcomes. One hundred and one women whose husbands had died from cancer within the last year served as participants. Mean age of this relatively well-educated, predominately Caucasian sample was 54 years old. Median time since death was between 6 months and a year. Results supported the hypotheses that bereavement coping self-efficacy was a significant predictor of emotional distress, psychological well-being, spiritual well-being, and physical health perceptions after controlling for several other important factors. Theoretical and clinical ramifications of these findings are discussed.

Adaptation, Psychological↗
PubMed2001

Initiation and propagation of calcium-dependent action potentials in a coupled network of olfactory interneurons.

Coherent oscillatory electrical activity and apical-basal wave propagation have been described previously in the procerebral (PC) lobe, an olfactory center of the terrestrial slug Limax maximus. In this study, we investigate the physiological basis of oscillatory activity and wave propagation in the PC lobe. Calcium green dextran was locally deposited in the PC lobe; this led to cellular uptake and transport of dye by bursting and nonbursting neurons of the PC lobe. The change of intracellular calcium concentration was measured at several different positions in neurites of individual bursting neurons in the PC lobe with a two-photon laser-scanning microscope. Fluorescence measurements were also made from neurons intracellularly injected with calcium green-1. Two different morphological classes of bursting neurons were found, varicose (VB) and smooth (SB). Our results from concurrent optical and intracellular recordings suggest that Ca2+ is the major carrier for the inward current during action potentials of bursting neurons. Intracellular recordings from bursting neurons with nystatin perforated-patch electrodes made while simultaneously recording the local field potential (LFP) with extracellular electrodes indicate that the burster spikes are precisely phase-locked to the periodic LFP events. By referencing successive calcium measurements to the common LFP signal, we could therefore accurately determine the relative timing of calcium transients at different points along a neurite. Measuring the relation of temporal to spatial differences allowed us to estimate the velocity of action potential propagation, which was 4.3 +/- 0.2 (SE) mm/s in VBs, and 1.3 +/- 0.2 mm/s in SB.

Action Potentials↗
PubMed2001

Model for olfactory discrimination and learning in Limax procerebrum incorporating oscillatory dynamics and wave propagation.

We extend our model of the procerebral (PC) lobe of Limax, which is comprised of a layer of coupled oscillators and a layer of memory neurons, each layer 4 rows by 20 columns, corresponding to the cell body layer (burster cells) and neuropil layer (nonburster cells) of the PC lobe. A gradient of connections in the layer of model burster cells induces periodic wave propagation, as measured in the PC lobe. We study odor representations in the biological PC lobe using the technique of Kimura and coworkers. Lucifer yellow injection into intact Limax after appetitive or aversive odor learning results in a band or patch of labeled cells in the PC lobe with the band long axis normal to the axis of wave propagation. Learning two odors yields two parallel bands of labeled PC cells. We introduce olfactory input to our model PC lobe such that each odor maximally activates a unique row of four cells which produces a short-term memory trace of odor stimulation. A winner-take-all synaptic competition enabled by collapse of the phase gradient during odor presentation produces a single short-term memory band for each odor. The short-term memory is converted to long-term memory if odor stimulation is followed by activation of an input pathway for the unconditioned stimulus (US) which presumably results in release of one or more neuromodulatory amines or peptides in the PC lobe.

Animals↗
PubMed2001

Diagnostic value of D dimer in pulmonary embolism and pneumonia.

BACKGROUND: Diagnosis of pulmonary embolism (PE) and its clear-cut differentiation with other entities of occasional similar presentation remains difficult in routine clinical practice. High plasmatic levels of D dimer (DD), a specific fibrin derivate, have recently been reported in PE. OBJECTIVE: The purpose of this study was to prospectively evaluate the diagnostic value of plasmatic DD in a clinical setting. METHODS: We studied 52 patients with PE proven with pulmonary scintigraphic studies in relation to 19 patients posteriorly diagnosed of having community-acquired pneumonia and 30 healthy subjects. Evolution of DD levels whilst the patients were on intravenous anticoagulant therapy was evaluated by measuring DD concentration on admission and on day 7 in 10 patients. RESULTS: Plasma DD levels were significantly higher in PE in relation to controls (p < 0.001). DD levels were also higher in patients diagnosed with community-acquired pneumonia in relation to controls (p < 0.05) but lower than those obtained in high probability PE (p < 0.05). Sensitivity and specificity of plasmatic DD in the emergency diagnosis of PE are of 92 and 71%, respectively. Plasma levels of DD were found to progressively decrease during the first week of heparin therapy, but they remained higher than in control subjects. CONCLUSIONS: Plasma DD levels are increased in patients with suspected PE and the degree of elevation is related to the results obtained in scintiscans. Moreover, DD concentrations progressively decrease during the first week of anticoagulant therapy. The increased DD levels found in patients with pneumonia make this test useless in the differential diagnosis between these two clinical entities.

Adult↗
PubMed2001

Prevalence of infection with hepatitis C virus in Venezuela, as assessed with an immuno-assay based on synthetic peptides.

Information on infection with hepatitis C virus (HCV) in South America is scarce. The seroprevalences of antibodies to HCV among urban, rural and Amerindian populations from Venezuela, and the genotypes of the HCV isolates recovered, were therefore determined. A total of 2592 sera were tested with an immuno-assay which was developed in-house and based on synthetic peptides. Each reactive sample was then re-tested, using other enzyme immuno-assays and a reverse-transcription, nested PCR, and any sample confirmed positive (in any test) was considered HCV-positive. Genotypes were determined by analysis of RFLP. Overall, 39 (1.5%) of the samples were found HCV positive. The results of the immuno-assays indicated that the seroprevalence of HCV markers among the Amerindians investigated (23/1082, or 2.1%) was significantly higher than that among the other subjects (16/1510, or 1.1%; P = 0.02). No such difference was observed in the numbers of subjects confirmed positive by PCR, however (6/1082 v. 10/1510), and some of the anti-HCV reactivity observed among Amerindians may have been the result of cross-reactivity with parasitic infections. The relative low prevalence of active HCV infection (16/2582, or 0.6%) and the HCV genotypes observed (mainly genotype 1) are in agreement with the results of previous studies indicating that HCV is not autochthonous to South America. However, it is clear that the virus may now be found even in isolated Amerindian populations. The in-house, synthetic-peptide-based immuno-assay seems to be a valuable tool for epidemiological studies.

Adolescent↗
PubMed2001

Femoral vein valve repair with angioscopy-assisted anterior valve sinus plication. Early results.

BACKGROUND: The efficiency of angioscopy-assisted anterior valve sinus plication for primary deep venous insufficiency was evaluated. METHODS EXPERIMENTAL DESIGN: retrospective, clinical study with short follow-up. SETTING: institutional practice. PATIENTS: 15 limbs in 12 patients had class 4 or higher disease (SVS/ISCVS classification). Descending venography showed class 3 or 4 reflux in all patients. Venous refilling time (VRT) was abnormal (<15 sec) in all of the nine limbs in which photoplethysmography was conducted. The limbs were treated with angioscopy-assisted anterior valve sinus plication of the superficial femoral vein. Postoperative descending venography was performed between the first and third day after operation. Clinical evaluation and VRT measurement were repeated when the patients were discharged and checked at the outpatient office. RESULTS: Mean follow-up was 22 weeks with a range of 1 to 70 weeks. At postoperative descending venography, the reflux of the superficial femoral vein was significantly improved. At final follow-up, all patients reported greater or lesser relief of subjective symptoms. In four limbs with class 6 disease, ulcers healed and did not recur. In one limb with class 5 disease, ulcers did not recur. In the other 10 limbs with class 4 disease, a distinct clinical improvement occurred with resolution of skin changes. VRT was normal in 11 of the 12 limbs examined. CONCLUSIONS: Our preliminary experience demonstrates that angioscopy-assisted anterior valve sinus plication gives early good clinical and hemodynamic improvement in patients with primary deep venous insufficiency.

Adult↗
PubMed2001

Popliteal artery entrapment syndrome. Reconstruction of the transected medial head of the gastrocnemius muscle.

Popliteal artery entrapment syndrome (PAES) is an uncommon cause of arterial insufficiency, especially in younger, athletic patients. Surgical treatment should be performed in all cases of PAES whether the artery is occluded or not. Although transection of the compressing muscle or fascial band is required to obtain good results, controversy exists about reconstruction of the transected muscle or fascial band. We present a case of a young athlete with PAES for whom rapid recovery of the athletic activity was provided by reconstruction of the divided medial head of the gastrocnemius muscle.

Adolescent↗
PubMed2000

Early human immunodeficiency virus (HIV) infection in the HIV Network for Prevention Trials Vaccine Preparedness Cohort: risk behaviors, symptoms, and early plasma and genital tract virus load.

Risk behaviors, symptoms, and virologic characteristics were studied among 103 human immunodeficiency virus (HIV) seroconverters in vaccine preparedness cohorts during 1995-1998. Overall, 83% of subjects were men who had sex with men; most reported multiple risk episodes and symptoms (84%, > or =1 symptom) during seroconversion. Acute HIV was diagnosed in only 8 of 50 who sought medical care. Median initial pretreatment plasma virus load was 25,800 copies/mL (range, undetectable-262,000 copies/mL) a mean of 4 months after seroconversion, and 9.7% had nucleoside-associated mutations; none had multidrug resistance. Semen virus load was more variable, 1.3 log(10) lower and modestly correlated (r=.28; 95% confidence interval, 0.16-0.42) with plasma among untreated men. When the plasma RNA level was <5000 copies/mL, 32% of untreated men, 13% on nucleoside regimens, and 7% on protease inhibitor-containing regimens had detectable seminal RNA. Acute HIV was seldom diagnosed, representing missed opportunities for early treatment and prevention. Most subjects had several relatively stable virus loads before initiation of antiretrovirals, indicating feasibility of assessing HIV vaccines on virus set point in efficacy trials.

Acute Disease↗
PubMed2000

Identification of highly conserved and broadly cross-reactive HIV type 1 cytotoxic T lymphocyte epitopes as candidate immunogens for inclusion in Mycobacterium bovis BCG-vectored HIV vaccines.

One of the fundamental goals of current strategies to develop an efficacious vaccine for AIDS is the elicitation of cytotoxic T lymphocyte (CTL) reactivities capable of recognizing cells infected with different subtypes of the human immunodeficiency virus type 1 (HIV-1). In efforts to explore new vaccine candidates by the UNAIDS/WHO Vaccine Committee, we review the most recent data concerning CTL epitopes that are conserved among the different HIV-1 subtypes. Moreover, we examine HLA allelic frequencies in several different populations, to determine those that could contribute to the goal of a cumulative phenotype frequency (CP) of at least 80%. By analyzing conserved epitopes in the context of HLA restricting alleles, we define a set of HIV-1 gene regions that may have the greatest potential to induce cross-clade reactive CTLs. The absence of well-defined correlates of immune protection that link CTL epitopes to delayed disease progression and/or prevention of infection does not permit an assignment of rank order of the most relevant component of a candidate vaccine. Thus far, most of the studies conducted in clade B-infected patients to define conserved and immunodominant epitopes indicate gag and pol gene products to be the most conserved among the HIV-1 subtypes. Moreover, anti-Pol and -Gag CTL responses appear to correlate inversely with disease progression, suggesting that they should be among the first choice of antigens to be included in a candidate vaccine construct aimed at induction of broad CTL responses. The impact of a clade B-based vaccine as a worldwide candidate capable of inducing protective immune responses can be determined only after "in vivo" studies. Meanwhile, extensive parallel studies in populations infected with non-clade B HIV-1 subtypes should define the patterns of immunodominant epitopes and HLA for comparison with the data already collected in clade B-infected subjects.

AIDS Vaccines↗