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Biomedical subjects

A Vázquez

Publications and source records attributed to A Vázquez.

At least 19 recordsLinked to original sources
PubMed2003

The transplantation donation process in the Centro de Investigaciones Medico Quirurgicas of Cuba: 1999-2002.

OBJECTIVE: In 1998 in the Centro de Investigaciones Medico Quirurgicas the Transplant Coordination Office (TCO) was created, with the aim to organize a system to support a hepatic transplantation program. This organization, which changed the transplantation-donation process not only in our center but in the whole country, is described in this article. METHOD: The files of donors generated in our hospital were studied together with the transplant coordination records, from 1999 till the first half of 2002. RESULTS: In the period studied, 21 potential donors were diagnosed with brain death, yielding a donation rate of 71.4%. Brain death was most frequently caused by vascular brain disease; however, in the realized donor group, the cranioencephalic trauma predominated. The typical donor was a man of average age 39.2 years (range, 18-86 years). Among the potential donors, 24% were excluded based on medical criteria, and 5% due to family objections. Forty liver transplantation were performed in 36 patients including 1 liver-kidney simultaneous procedure. The principal etiologies for transplant included hepatitis C virus cirrhosis, 22%; alcoholic, 19%; and acute hepatic failure, 13%. Kidney transplantations were performed in 70 patients, including 41 from cadaveric donors (53.6%) and 29 from living related donors (41.4%). In 2001, a pancreas-kidney transplantation program was started. CONCLUSION: The creation of the TCO has been of paramount importance to optimize transplantation program functions.

Adolescent↗
PubMed2003

Infection of human monocytes with Mycobacterium bovis BCG induces production of CC-chemokines.

DESIGN: CC-chemokines are potent leukocyte activators and chemoattractants, which have an important role in granuloma formation, function critical for the immune responses to mycobacterial infection. This study investigated whether infection of human monocytes with Mycobacterium bovis bacillus Calmette-Guérin (BCG) elicits secretion of RANTES, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta. METHODS: RANTES, MIP-1alpha and MIP-1beta synthesis was measured by the presence of protein secretion in the cell culture supernatant as determined by enzyme-linked immunosorbent assay. To investigate the mechanism of M. bovis BCG stimulation of RANTES, we carried out inhibition assays with antibodies to CD40 and we used an intracellular calcium chelator BAPTA-AM. RESULTS: Infection of human monocytes with M. bovis BCG induced RANTES, MIP-1alpha and MIP-1beta secretion in a dose-dependent manner. This stimulation of CC-chemokines production was not attributed to LPS contamination. M. bovis-induced RANTES secretion was dependent upon bacterial uptake and on tumor necrosis factor (TNF)-alpha. Interestingly, the production of RANTES by M. bovis BCG-infected monocytes occurs through a mechanism that requires intracellular calcium and was significantly inhibited (P<0.05) with antibodies to CD40. CONCLUSIONS: These results suggest that the ability of M. bovis BCG to produce CC-chemokines might lead to protection in the acquired immune response of mycobacterial infection and at the same time indicate that M. bovis BCG-induced RANTES secretion is mediated by CD40 and dependent on the intracellular calcium influx.

Chemokine CCL3↗
PubMed2003

Main pancreatic duct: morphlogy after acute biliary pancreatitis with magnetic resonance cholangiopancreatography after secretin stimulation.

OBJECTIVE: to assess whether a magnetic resonance cholangiopancreatography performed after an acute biliary pancreatitis leads to pancreatic morphological alterations and if secretin stimulation influences the visualization of the pancreatic tree. METHOD: forty patients with acute biliary pancreatitis, 25 female (62,5/) and 15 male (37,5/), 27 mild and 13 severe, were prospectively and consecutively studied. All patients had undergone cholecystectomy. No altered pancreatic functions were observed. Morphology of the pancreas and of the main pancreatic duct were assessed by magnetic resonance cholangiopancreatography five years after the episode of pancreatitis and a comparative study between patients and case controls was carried out. Secretin was given in 16 cases in whom the visualization of the duct was incomplete or absent. Ductal morphology before and after secretin stimulation was compared. RESULTS: significant differences were observed when the diameter and length of the main pancreatic duct were compared in patients and control cases and was completely visualized in 60% of the cases, and could be seen in all patients after secretin stimulation. The comparative statistical analysis of the length and diameter of the pancreatic duct before and after the secretin stimulation showed significant differences. CONCLUSION: acute biliary pancreatitis leads to morphological alterations, regarded as scar lesions which do not become chronic. Secretin stimulation improves the visualization of the main pancreatic duct.

Acute Disease↗
PubMed2002

[Primary low-grade non-Hodgkin's B lymphoma mimicking meningioma].

Primary dural lymphomas are rare. Usually they present themselves as diffuse lesions and are infrequently well-delimited. We present a 44 year old male, who was admitted into our Centre after a generalised seizure. Neuroimage studies (CT scan, MRI and angiography) were performed, demonstrating a right hemispheric well-delimited extra-axial mass, being diagnosed initially as meningioma. The patient underwent surgery with radical scission of the mass and dural margins. Histopathological diagnosis was Non-Hodgkin B-Cell lymphoma (marginal B-Cell lymphoma), which nowadays is considered as MALT lymphoma (Mucosa Associated Lymphoid Tissue). Studies directed to establish tumour extension didn't demonstrate the existence of another lesions in the organism.

Adult↗
PubMed2002

Signals involved in mycobacteria-induced CXCL-8 production by human monocytes.

CXC chemokine-interleukin-8 (IL-8) (CXCL-8) is a potent proinflammatory chemotactic factor that induces important immune responses for antimycobacterial defenses. However, little is known about the biochemical mechanisms by which the mycobacterial antigens upregulate the release of CXCL-8 from human monocytes. In this study, the mechanisms through which Mycobacterium bovis BCG induces CXCL-8 secretion in human monocytes were investigated. We found that M. bovis BCG induced the production of high levels of CXCL-8 by human monocytes. M. bovis-induced CXCL-8 secretion was unaffected by the protein kinase C (PKC) inhibitor bisindolylmaleimide. In contrast, preincubation of the monocytes with the protein tyrosine kinase (PTK) inhibitor genistein resulted in dose-dependent suppression of mycobacteria-induced CXCL-8 secretion. These results were further supported by the fact that treatment of monocytes with herbimycin-A, another well-described inhibitor of PTK activity with a different mechanism of action, significantly diminished the effect of M. bovis on CXCL-8 secretion. In addition, the specificity of this inhibition was demonstrated by the inability of herbimycin-A to block in a significant manner IL-1 beta induction of CXCL-8. Herbimycin-A significantly blocked tyrosine phosphorylation of p59(hck) in response to M. bovis. Finally, two specific NF-kappa B inhibitors, sulfasalazine and caffeic acid phenetyl ester (CAPE), strongly inhibited the production of CXCL-8 by human monocytes infected with M. bovis. These results show intracellular signaling pathways and a transcription factor involved in the M. bovis-mediated upregulation of CXCL-8 biosynthesis and release by human monocytes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

[Anterior sacral meningocele with Currarino's syndrome: report of two cases].

The anterior sacral meningocele is the congenital hernia of the thecal sac into the pelvis through a bone defect of the anterior wall of the sacrum. The association of anorectal anomaly, anterior sacral defect and presacral mass, known as Currarino's triad, can be diagnosed during the first decade of life in the eighty per cent of the cases However, in the incomplete syndrome, the symptoms appear in adults. In order to avoid late complications and due to the clear genetic origin of this uncommon pathology, the investigation of the family is of paramount importance for the early diagnosis and treatment. We review the literature and add two cases of anterior sacral meningocele with rectal fistula and incomplete Currarino's syndrome. In one of the cases the pathology is also present in another member of the same family and is complicated with meningitis. The importance of early diagnosis and treatment of these malformations and the need for fammily genetic investigation are discussed.

Adult↗
PubMed2001

Dynamical and correlation properties of the internet.

The description of the Internet topology is an important open problem, recently tackled with the introduction of scale-free networks. We focus on the topological and dynamical properties of real Internet maps in a three-year time interval. We study higher order correlation functions as well as the dynamics of several quantities. We find that the Internet is characterized by non-trivial correlations among nodes and different dynamical regimes. We point out the importance of node hierarchy and aging in the Internet structure and growth. Our results provide hints towards the realistic modeling of the Internet evolution.

Internet↗
PubMed2001

A sequential protocol combining dual neuroanatomical tract-tracing with the visualization of local circuit neurons within the striatum.

We describe here an experimental approach designed to aid in the identification of complex brain circuits within the rat corpus striatum. Our aim was to characterize in a single section (i) striatal thalamic afferents, (ii) striatopallidal projection neurons and (iii) striatal local circuit interneurons. To this end, we have combined anterograde tracing using biotinylated dextran amine and retrograde neuroanatomical tracing with Fluoro-Gold. This dual tracing protocol was further implemented with the visualization of different subpopulations of striatal interneurons. The subsequent use of three different peroxidase substrates enabled us to unequivocally detect structures that were labeled within a three-color paradigm.

3,3'-Diaminobenzidine↗
PubMed2001

Roles of intracellular calcium and NF-kappaB in the Bacillus Calmette-Guérin-induced secretion of interleukin-8 from human monocytes.

Interleukin (IL)-8 secretion contributes to the early host response against mycobacterial infection by increasing local inflammation and recruiting professional phagocytes. Because the mechanisms through which Mycobacterium bovis Calmette-Guérin (BCG) induces IL-8 secretion are unknown, the aim of the present study was to characterize the nature of IL-8 production induced by BCG in human monocytes. In this study, we found that the induction of IL-8 synthesis was dose- and time-dependent after stimulation with BCG. This IL-8 secretion was not attributed to LPS contamination or the presence of TNF-alpha. We also determined that BCG-induced IL-8 secretion occurs through a mechanism that requires intracellular calcium and likely involves a calmodulin-sensitive step. Interestingly, BCG-induced secretion of IL-8 from human monocytes resulted from transcriptional up-regulation of the IL-8 gene. Moreover, we present evidence that BCG activates nuclear translocation of the transcription factor NF-kappaB, since pretreatment of monocytes with sulfasalazine, a inhibitor of NF-kappaB activity, blocked the ability of BCG to induce IL-8 secretion in a dose-dependent manner, producing 92.5% inhibition at a concentration of 2 mM. These results were further supported by the fact that treatment of cells with curcumin, another well-described inhibitor of NF-kappaB activity with a different mechanism of action, significantly diminished the effect of BCG on IL-8 secretion. Together, these studies are the first to demonstrate that BCG-induced IL-8 secretion by human monocytes appears to be mediated by intracellular Ca(2+) and is NF-kappaB-dependent and at the same time suggest that production of IL-8 in response to M. bovis BCG can contribute to the initial local and systemic inflammatory response in human tuberculosis.

Calcium↗
PubMed2001

[Safety and efficacy of an early deambulation protocol after PTCA with an angio-seal device].

INTRODUCTION: In order to assess the efficacy and safety of an early deambulation (1-2 h) protocol after coronary angioplasty using the Angio-seal collagen plug, we analyzed a consecutive series of patients treated with this device versus a reference group treated with mechanical compression. PATIENTS AND METHODS: Two hundred and seven coronary angioplasty patients were included from February to August 2000. Ninety-eight were treated with mechanical compression and one hundred and nine with the Angio-seal collagen plug. All patients were followed at discharge and fifteen days after surgery. RESULTS: Eighty percent of the patients receiving the Angio-seal device achieved immediate hemostasis (< 1 min). In patients with mechanical compression hemostasis was achieved within 30 min in 68.3%, whereas 25.5% of patients required more than 40 min. First deambulation in the Angio-seal group was achieved within 2 h in 94.5% of the patients. The incidence of major complications was low in both groups (1 case in the Angio-seal group and 2 in the C-clamp group) without statistically significant differences. The Angio-seal group showed a lower incidence of overall vascular complications as compared to the C-clamp group (4.6% vs. 14.3%; p = 0.02). CONCLUSION: Following our protocol, an early deambulation strategy after coronary angioplasty with the use of the Angio-seal collagen plug was feasible, safe and efficacious.

Adult↗
PubMed2001

Protein tyrosine kinase regulates FAS-mediated apoptosis in human BCG-infected monocytes.

Apoptosis of monocytes/macrophages has emerged as a central regulatory event in the defense against mycobacterial infections. The involvement of protein tyrosine kinases (PTK) in Fas-mediated apoptosis in T cells is well established, but the possible role of PTK in Fas-dependent death of human bacillus Calmette-Guerin (BCG)-infected monocytes remains unclear. Here, we first examined the expression and function of Fas on BCG-infected human monocytes by flow cytometry. The results demonstrated that BCG-infected monocytes expressed significant Fas protein levels. In addition, engagement of the Fas antigen with its agonistic antibody (Ab) resulted in apoptosis of monocytes, as monitored by DNA analysis and fluorescence-activated cell sorter (FACS) analysis. The apoptotic action of Fas was suppressed significantly by genistein, indicating a role for PTK in this death process. Consistent with this observation, herbimycin A and tyrphostin, two selective tyrosine kinase inhibitors with different mechanisms of action, effectively inhibited Fas-mediated apoptosis of BCG-infected monocytes, as demonstrated by DNA content analysis. Moreover, we confirmed the effect of genistein, herbimycin A, and tyrphostin by examining apoptosis with the terminal transferase dUTP nick endlabeling (TUNEL) assay. Collectively, these data demonstrate that Fas-induced apoptosis may represent an important mechanism for eliminating BCG-activated human monocytes and that this apoptosis is due, at least in part, to signaling via a PTK pathway.

Apoptosis↗
PubMed2001

123Iodine-labelled anti-VCAM-1 antibody scintigraphy in the assessment of experimental colitis.

OBJECTIVES: To evaluate the usefulness of 123I-labelled anti-vascular cell adhesion molecule-1 (VCAM-1) monoclonal antibody (MAb) scintigraphy in the assessment of colonic inflammatory damage. DESIGN: Colitis was induced by intracolonic administration of 30 mg trinitrobenzenesulphonic acid in 0.5 ml of 50% (v/v) ethanol. Rats injected with vehicle served as controls. Animals were studied at day 7 after induction of colitis. METHODS: Scintigraphy was performed in control and trinitrobenzenesulphonic acid-induced colitic rats 2, 4 and 24 h after intravenous administration of 123I-anti-VCAM-1 MAb. Scintigraphic uptake was quantified in selected areas on scintigraphs. Animals were killed, tissue 123I radioactivity accumulation was measured, and accumulation of anti-VCAM-1 MAb in each organ was calculated. 99mTc-hexamethyl propylene amine oxime-labelled leucocyte scintigraphy was performed in additional groups of animals for comparison. RESULTS: Colonic tracer uptake was visible in scans of colitic, but not control animals. Quantification of scintigraphic uptake in the colon was significantly higher in colitic rats than in control animals (P< 0.0001). The specificity of the increase was demonstrated by lack of 123I-labelled non-binding MAb uptake in the colon, and by displacement of 123I-anti-VCAM-1 MAb colonic uptake by pre-treatment with unlabelled MAb. Accumulation of anti-VCAM-1 MAb in the colon of colitic rats was eightfold higher than in control animals. Strong correlations were found between quantification of scintigraphic uptake, anti-VCAM-1 MAb accumulation, histological damage and myeloperoxidase activity in the colon. CONCLUSION: 123I-labelled anti-VCAM-1 MAb scintigraphy allows an accurate evaluation of colonic inflammatory damage in trinitrobenzenesulphonic acid-induced colitis, suggesting a potential role for this imaging technique in the assessment of human IBD.

Animals↗
PubMed2000

Studies on the biosynthesis of taxol. Synthesis Of taxa-4(20), 11(12)-diene-2alpha,5alpha-diol.

The synthesis of taxa-4(20),11(12)-diene-2alpha,5alpha-diol is described. An improved procedure for the intramolecular Diels-Alder cycloaddition previously reported in our synthesis of taxa-4(5), 11(12)-diene has been utilized to prepare a taxoid with oxygenation in the B and C rings. It has been established previously that taxa-4(20),11(12)-dien-5alpha-ol is the first oxygenated intermediate on the biosynthetic pathway to Taxol. Taxa-4(20), 11(12)-diene-2alpha,5alpha-diol (5), which has been observed in a biosynthetic conversion, is a potential candidate as the second oxygenated intermediate on the Taxol biosynthetic pathway, has been prepared to probe the intermediacy of this substance.

Antineoplastic Agents, Phytogenic↗
PubMed2000

A new antibacterial compound from Ibicella lutea.

Ibicella lutea is a 'quasi-carnivorous' plant that grows wild in Uruguay where it is used in popular medicine as an antiseptic for eye and skin infections. In an earlier screening, it showed a broad antibacterial spectrum. From the chloroform extract of the plant the main antibacterial compound has now been isolated and identified by several MS and NMR methods as a new compound, 11-O-(6'-O-acetyl-beta-D-glucopyranosyl)-stearic acid.

Anti-Infective Agents↗
PubMed2000

Different hippocampal activity profiles for PKA and PKC in spatial discrimination learning.

Protein kinases are considered essential for the processing and storage of information in the brain. However, the dynamics of protein kinase activation in the hippocampus during spatial learning are poorly understood. In this study, rats were trained to learn a holeboard spatial discrinmination task and the activity profiles for cyclic adenosine monophosphate (cAMP)-dependent protein kinase (PKA) and Ca2+/ phospholipid-dependent protein kinase C (PKC) in the hippocampus were examined. Hippocampal PKA activity increased rapidly on Day 1 of spatial learning and remained moderately high at later stages of acquisition. In contrast, PKC activity increased in particulate fractions compared with cytosolic fractions after habituation training and was maximal at Day 3 of spatial acquisition. The results establish a temporal dissociation between PKA and PKC during acquisition of spatial discrimination learning.

Animals↗
PubMed2000

13C-urea breath test for the diagnosis of Helicobacter pylori infection: are basal samples necessary?

AIM: The 13C-urea breath test (13C-UBT) is one of the best methods for the diagnosis of Helicobacter pylori infection. Basal breath samples are usually obtained, in addition to those obtained after urea intake, as it has been suggested that basal values may oscillate among a population (e.g. depending on diet). However, the superiority of this strategy has not been sufficiently demonstrated. The elimination of basal samples in the 13C-UBT protocol would have the advantages of higher simplicity and speed. METHODS: The 13C-UBT was performed in 714 consecutive patients. Mean age was 48 +/- 16 years, 49% were males, and in 48% of the patients previous H. pylori eradication therapy had been administered. Basal samples (13C-basal) and at 30 min after taking 100 mg of urea labelled with 13C (13C-post-urea) were obtained, delta over baseline (13C-DOB) being the algebraic difference between the ratio 13C/12C at these two points (which is the parameter usually given in studies, being considered positive when > 5%). A citric acid solution was used prior to urea intake. RESULTS: The prevalence of H. pylori infection was 48%. Mean values of 13C-basal, 13C-post-urea, and 13C-DOB were, respectively, -19 +/- 2, 5.9 +/- 33, and 25 +/- 33. 13C-basal values oscillated between -25 and -14, being between -21 and -16 in 90% of the cases. Linear correlation coefficient for 13C-post-urea and 13C-DOB was 0.999 (determination coefficient, 0.998; P< 0.0001). The area under the receiver operating characteristic (ROC) curve for the diagnosis of infection when only 13C-post-urea was used (taking 13C-DOB >5% as the 'gold standard') was 0.997. Best results were obtained with 13C-post-urea cut-off point set at -13, with sensitivity of 97.4% (95% CI, 95-99%), specificity of 99.5% (98-100%), and positive likelihood ratio of 180. The concordance kappa value for both tests (13C-post-urea and 13C-DOB) using the aforementioned cut-off point was 0.97. CONCLUSION: When performing the 13C-urea breath test it is sufficient to obtain samples 30 min after urea intake. Basal breath samples would not be necessary, which further simplifies this diagnostic method.

Adult↗
PubMed2000

[Arterial hypertension in Cuba. General overview of the past 25 years].

A general overview of hypertension as a major health problem in Cuba in the last 25 years are presented. In the first period, 1974-1990 was created a National Hypertension High Commission by the Minister of Public and the First national program for prevention and Control of Hypertension in Cuba was launched. To define high blood pressure in adults 15 years and older the cut-off point was set at 160/95 mmHg. The prevalence found was 15% in urban areas and 7-8% in rural areas. The second period, 1991-1998 the original National program was re-evaluated in 1990 and 1995. The new blood pressure cut-off point was set at 140/90 mmHg. The prevalence increased to 30.6% in urban areas and 15% in rural areas and incidence of 2.5% annual. A total of 862,303 hypertensive patients were registry at the end of 1997 which represents less than 40% of the total number of possible hypertensive patients. A National Campaign was launched in 1998. In 9 months the preliminary reports were: 25% increase in prevalence, registry and follow-up of hypertensive patients 15 years old and older (8.5% to 12.5%); 92.9% of primary care doctors and 89.5% of primary care nurses received training; improvement in public education and social support; improvement in risk factor awareness in general public and improvement of hypotensive drugs availability and splygmomanometers supplies.

Cuba↗