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Biomedical subjects

P Reyes

Publications and source records attributed to P Reyes.

At least 19 recordsLinked to original sources
PubMed2006

Effects of rivastigmine on cognitive function in patients with traumatic brain injury.

OBJECTIVE: To compare the efficacy and safety of rivastigmine (3 to 6 mg/day) vs placebo over 12 weeks in patients with traumatic brain injury and persistent cognitive impairment. METHODS: This prospective, randomized, double-blind, placebo-controlled study was conducted in 157 patients at least 12 months after injury. The primary efficacy measures were the Cambridge Neuropsychological Test Automated Battery (CANTAB) Rapid Visual Information Processing (RVIP) A' subtest and the Hopkins Verbal Learning Test (HVLT). The primary efficacy outcome was the proportion of patients who demonstrated 1.0 SD or greater improvement from baseline at week 12 on CANTAB RVIP A' or HVLT. RESULTS: The percentage of responders at week 12 on either the CANTAB RVIP A' or HVLT was 48.7% for rivastigmine and 49.3% for placebo (p = 0.940). Furthermore, for the overall study population, there were no significant differences for any of the secondary efficacy variables. In a subgroup of patients with moderate to severe memory impairment (n = 81), defined as 25% impairment or greater on HVLT at baseline, rivastigmine was significantly better than placebo for a number of measures, including the proportion of HVLT responders and CANTAB RVIP mean latency. CONCLUSIONS: Rivastigmine was safe and well tolerated in patients with traumatic brain injury with cognitive deficits. Rivastigmine shows promising results in the subgroup of patients with traumatic brain injury with moderate to severe memory deficits.

Adolescent↗
PubMed2005

Effects of perinatal asphyxia on cell proliferation and neuronal phenotype evaluated with organotypic hippocampal cultures.

The present report summarizes studies combining an in vivo and in vitro approach, where asphyxia is induced in vivo at delivery time of Wistar rats, and the long term effects on hippocampus neurocircuitry are investigated in vitro with organotypic cultures plated at postnatal day seven. The cultures preserved hippocampus layering and regional subdivisions shown in vivo, and only few dying cells were observed when assayed with a viability test at day in vitro 27. When properly fixed, cultures from asphyxia-exposed animals showed a decreased amount of microtubule-associated protein-2 immunocytochemically positive cells (approximately 30%), as compared with that from controls. The decrease in microtubule-associated protein-2 immunocytochemistry was particularly prominent in Ammon's horn 1 and dentate gyrus regions (approximately 40%). 5-Bromo-2'deoxyuridine labeling revealed a two-fold increase in cellular proliferation in cultures from asphyxia-exposed, compared with that from control animals. Furthermore, confocal microscopy and quantification using the optical disector technique demonstrated that in cultures from asphyxia-exposed animals approximately 30% of 5-bromo-2'deoxyuridine-positive cells were also positive to microtubule-associated protein-2, a marker for neuronal phenotype. That proportion was approximately 20% in cultures from control animals. Glial fibrillary acidic protein-immunocytochemistry and Fast Red nuclear staining revealed that the core of the hippocampus culture was surrounded by a well-developed network of glial fibrillary acidic protein-positive cells and glial fibrillary acidic protein-processes providing an apparent protective shield around the hippocampus. That shield was less developed in cultures from asphyxia-exposed animals. The increased mitotic activity observed in this study suggests a compensatory mechanism for the long-term impairment induced by perinatal asphyxia, although it is not clear yet if that mechanism leads to neurogenesis, astrogliogenesis, or to further apoptosis.

Animals↗
PubMed2005

[All-trans retinoic acid induces apoptosis in human mesangial cells: involvement of stress activated p38 kinase].

All-trans retinoic acid (AR-t) is used for treating acute promyelocytic leukemia and renal cell carcinoma and it also has therapeutic value in several animal models of renal disease. Among its renal targets, mesangial cells have been widely studied: they have both retinoic acid receptors (RAR) and retinoid X receptors (RXR) and the cell growth is inhibited when human mesangial cells are incubated with 1-10 microM AR-t. Although his effect has been related with the antiproliferative action of AR-t, there are no studies on the involvement of apoptosis in AR-t induced cell growth when higher concentrations of retinoid are used. Our studies show that 25 microM AR-t triggers mesangial cell apoptosis assessed by light and fluorescence microscopy (Giemsa stain and acridine orange stain, respectively), DNA electrophoresis, flow cytometry (annexin-V) and immunocytochemistry (TUNEL). AR-t induced apoptosis was not inhibited by preincubation with the RXR pan-antagonist HX531 nor with the RAR pan-antagonist AGN 193109, this suggesting RAR and RXIR are not involved in AR-t induced cell death. Previous results of our group showed that ERK (extracellular regulated kinase) and INK (c-Jun kinase), two members of the MAP (mitogen activated protein) kinase family, are involved in non apoptotic effects of AR-t on mesangial cells. Therefore we focussed on the stress activated p38 kinase, the third member of the MAPK family, to investigate its involvement in AR-t induced apoptosis. The results confirmed a role of p38 since: 1) preincubation with B5203589, a p38 inhibitor, inhibited ARA induced apoptosis; 2) incubation with AR-t induced p38 phosphorilation after few minutes and p38 remained phosphorilated for at least 8 hours and 3) AR-t induced p38 phosphorilation was inhibited by SB203589. These data suggest that AR-t might have toxic side effects on the kidney but also suggest that AR-t could be an useful inhibitor of pathological mesangial cell expansion.

Apoptosis↗
PubMed2003

Retinoids as a potential treatment for experimental puromycin-induced nephrosis.

1 Puromycin aminonucleoside (PAN)-induced nephrosis is a model of human minimal change disease. In rats, PAN induces nephrotic-range proteinuria, renal epithelial cell (podocyte) damage, infiltration of mononuclear leukocytes, and apoptosis of several renal cell types. 2 Retinoic acid (RA) modulates a wide range of biological processes, such as inflammation and apoptosis. Since renal damage by PAN is characterized by inflammatory infiltration and epithelial cell death, the effect of treatment with all-trans RA (tRA) was examined in the PAN nephrosis model and in the cultured differentiated podocyte. 3 Treatment with tRA 4 days after PAN injection did not inhibit the proteinuria peak but reversed it significantly. However, treatment with tRA both before and 2 days after the injection of PAN protected the glomerular epithelial cells, diminishing the cellular edema and diffuseness of the foot process effacement. Preservation of the podocyte architecture correlated with the inhibition of proteinuria. The anti-inflammatory effect of tRA was evidenced by the inhibition of PAN-induced interstitial mononuclear cell infiltration and the decreased renal expression of two molecules involved in monocyte infiltration: fibronectin and monocyte chemoattractant protein-1. TUNEL assays showed that tRA inhibited the PAN-induced apoptosis of cultured differentiated mouse podocytes. 4 We conclude that tRA treatment may prevent proteinuria by protecting the podocytes from injury and diminishing the interstitial mononuclear infiltrate in the model of PAN nephrosis. Retinoids are a potential new treatment for kidney diseases characterized by proteinuria and mononuclear cell infiltration.

Administration, Oral↗
PubMed2003

Richter's syndrome after allogeneic stem cell transplantation for chronic lymphocytic leukaemia successfully treated by withdrawal of immunosuppression, and donor lymphocyte infusion.

Development of high-grade non-Hodgkin's lymphoma is a possible complication of chronic lymphocytic leukaemia/small lymphocytic lymphoma, known as Richter's syndrome (RS). Treatment for RS includes systemic chemotherapy and, recently, allogeneic stem cell transplantation (SCT). We describe a patient with B-chronic lymphocytic leukaemia who developed RS 4 months after allogeneic SCT from an HLA-identical sibling. The RS presented with systemic symptoms, lymphadenopathy, pancytopenia and serum lactate dehydrogenase elevation. The patient was treated with immunosuppressive drug withdrawal and a donor lymphocyte infusion (DLI) of 1 x 10(7) CD3/kg, leading to the disappearance of all symptoms and the attainment of complete donor chimerism. After 18 months of the therapeutic DLI, the patient continues in complete remission.

Erythrocytes↗
PubMed2001

Photocatalytic degradation of pentachlorophenol on TiO2 sol-gel catalysts.

The photocatalytic degradation of pentachlorophenol (PCP) in aqueous solution was investigated using TiO2 catalysts. The samples were prepared by the sol-gel method using different gelation pH and different calcination temperatures. The solids were characterized by specific surface area, X-ray diffraction, UV-Vis absorbance, FTIR and pentachlorophenol adsorption. The catalytic activity of the solids was evaluated in a conventional photoreactor at 298 K using 30 ppm of pentachlorophenol. It was found that the reaction follows a first-order reaction and the kinetic constant values change slightly with the pH of gelation and more significantly with the calcination temperature.

Adsorption↗
PubMed2000

Mesenchymal stem cells from osteoporotic patients produce a type I collagen-deficient extracellular matrix favoring adipogenic differentiation.

Mesenchymal stem cells (MSCs), precursor cells resident in the bone marrow, have the capacity to differentiate into bone, cartilage, fat, and connective tissue. We have recently reported that MSCs from "healthy" donors differ from cells obtained from osteoporotic postmenopausal women in their proliferation rate, mitogenic response to osteogenic growth factors, and potential to mineralize. The purpose of this study was to examine the factors that explain the differential capacity of MSCs derived from "healthy" control and osteoporotic postmenopausal women to support mineralization. In addition, we examined the factors that regulate the differentiation of osteoporotic cells into adipocytes. For this purpose, we isolated MSCs from bone marrow of donors and analyzed the synthesis and deposition of type I collagen, the main component of bone extracellular matrix, the time course of gelatinolytic activity expression, the deposition of transforming growth factor beta (TGF-beta), and the ability of cells to differentiate into adipocytes. Our results indicate that cells derived from osteoporotic donors synthesized 50% less type I collagen than normal cells and maintained higher levels of gelatinolytic activity under differentiation conditions (70% versus 15% after 14 days in culture). MSCs derived from osteoporotic women produced 60-65% less TGF-beta and expressed higher adipogenic capacity. We conclude that the capacity of MSCs derived from osteoporotic postmenopausal women to generate and maintain type I collagen-rich extracellular matrix is decreased, favoring their adipogenic differentiation. These observations may explain the decreased mineralization previously observed in these types of cells.

Adipocytes↗
PubMed2000

DNA sequencing of HLA-B alleles in Mexican patients with Takayasu arteritis.

Takayasu arteritis (TA) is characterized by a 'pulseless' condition and occurs frequently in young females from Asian and South American countries. It has been associated with Mayor Histocompatibility Complex (MHC) genes in different populations. Recent data indicate direct participation of HLA-B alleles in the susceptibility to the disease. This fact was explored in an associative study with TA to establish if some region in the exon 2, intron 2 or in the exon 3 of HLA-B alleles is common in the alleles associated with TA and at the same time to know if a specific sequence or an epitope, more than an allele, would be responsible for the susceptibility to this vasculitis. We studied HLA-B alleles of 12 Mexican patients with TA using PCR-SSP and sequencing. The analysis by PCR-SSP in 12 patients showed that five of them showed the B*15 allele, three the B*40 allele and two the B*39 allele, the remaining two presented the B*44 allele. Sequence analysis enabled us to define that the B*39 subtypes are B*3908; B*15 subtypes are B*1510, B*1515, B*1522 and B*1531; and the B*40 subtypes are B*4005 and B*4008. An individual with B*51 (B*5107) and another with B*52 (B*5201) alleles were also identified. The sequences of the intron 2 seem be heterogeneous. Analysis at the 63 and 67 positions of HLA-B alleles showed that 9 of them have similarity in some of these positions with the residues detected in the B*5201 and B*3902 alleles associated with TA in Asian populations. The results indicate that there is heterogeneity in the alleles associated with TA in Mexicans but, in spite of that heterogeneity, the alleles associates can be separated into three groups: B*39, B*15 and B*40, whose subtypes are rare and apparently of recent generation in Mexico, probably by recombination events at intron 2 level. The sequences analysis also shows that most of the alleles detected in the Mexican patients share two epitopes described in the susceptibility alleles in Asian populations, suggesting that these epitopes could be responsible for the susceptibility to develop the disease in spite of the allele in which are found.

Alleles↗
PubMed2000

[Validity of clinical tests to confirm or to exclude the diagnosis of acute appendicitis].

AIMS: The clinical usefulness of the diagnostic tests (usually employed to diagnose an acute appendicitis in a group of patients in which this diagnosis is clinically highly suspected). PATIENTS AND METHODS: A cross sectional study was designed. The sample (n = 116) was randomly selected by term and specific days from the patients attending the Emergency Service at Elda General Hospital in a year period. The method used was is a validity study making 2 x 2 tables. We have cross matched the habitual routine tests with: a) the clinical outcome if the patient was not surgically treated, or b) the result of the biopsy for those operated. Being these the gold standard. The validity indexes studied were sensibility (S), specificity (E). The 95% confidence index of the CF were calculated. RESULTS: Acute appendicitis clinical suspicion was confirmed in 29.4% (IC 95%: 20.8-38). The best validity indexes were: a) kind of pain (S = 81.3; E = 33.8); b) peritoneal inflammatory signs (S = 78.5%, E = 45.9%); c) presence of leucocytosis in blood exam (S = 100%, E = 54.5%), and d) a greater difference in axillary-rectum temperature (S = 13.6%, E = 96.6%). Only leucocytosis reached 0 for PP- and CP-; the blood leucocytosis (PP+ = 47.8%, CP+ = 2.20) and the axillary-rectum temperature (PP+ = 60%, CP+ = 4.0) dissociation were the test with most valuable indexes. CONCLUSIONS: Clinical suspicion of acute appendicitis in a group of patients having a great probability of suffering it over estimates this diagnosis. The symptoms or signs routinely used in the diagnosis did not reach high validity indexes in these patients. They are a poor help to stress or reject the diagnosis of acute appendicitis. To be careful is the main tool the doctors have. Blood leucocytosis is the test that has the best agreement indexes of clinical usefulness and it has the best countence with the gold standard.

Acute Disease↗
PubMed1999

Low flow veno-venous ECMO via subclavian dialysis catheter for severe respiratory failure.

BACKGROUND: We present the case of a 12-year-old female with severe postoperative bacterial pneumonia unresponsive to conventional treatment following a failed renal transplant. CASE REPORT: The patient was placed on low flow veno-venous extracorporeal membrane oxygenation (ECMO) as an adjuvant treatment to antibiotic therapy and maximal ventilatory support. Venous ECMO resulted in rapid improvement and the patient was successfully weaned after 48 hours of circulatory assistance. Two days later, the patient was extubated and safely discharged from the intensive care unit. Eighteen months later, she remains stable on peritoneal dialysis and is awaiting a new donor kidney. CONCLUSIONS: Low flow veno-venous ECMO represents a new therapeutic alternative for critically ill patients whose condition does not meet the conventional ECMO criteria. Further clinical experience is still needed.

Catheters, Indwelling↗
PubMed1997

At the crossroads: options for financing college health services in the 21st century.

At a time when increasing numbers of uninsured and underinsured students are attending college, many college health programs face formidable challenges in their efforts to sustain services. As financial pressures increase, college health programs must revisit their funding options, including (1) maintaining the current level and source of funding but requiring additional out-of-pocket fees for certain services from students, (2) establishing their own insurance plans, (3) qualifying as a preferred provider organization, or (4) some combination of the above. Whatever strategies are selected and pursued, college health programs must continue to try to provide quality services at a reasonable cost while maintaining an emphasis on prevention, health education, and the provision of services most needed by the college population, including mental health and substance abuse services.

Adolescent↗
PubMed1996

HLA-DR6 (possibly DRB1*1301) is associated with susceptibility to Takayasu arteritis in Mexicans.

Takayasu arteritis is characterized by a "pulseless" condition and occurs frequently in young females from Asian and South American countries. This disease has been found to be linked with major histocompatibility complex (MHC) antigens in Japanese individuals. In the present study we compared gene frequencies of class I, class II, and class III MHC genotypes in patients with Takayasu arteritis and ethnically matched healthy controls. Serological typing was confirmed by molecular typing at the DNA level. We found significant increases in the frequencies of human leucocyte antigen (HLA)-DR6 and HLA-B62 in patients compared to the healthy controls (P corrected [C] = 0.0007, relative risk [RR] = 5.08; PC = 0.05, RR = 3.13 respectively). However, since the number of patients was considerably lower than the number of controls this can be considered as a tendency and not a true association. On the other hand, we found a significantly decreased frequency of HLA-DR4 in patients compared to healthy controls (PC = 0.04, RR = 0.34). At the DNA level, all DR6-positive individuals were HLA-DRB1*1301 whereas controls were HLA-DRB1*1301 (4.2%). Takayasu arteritis in Mexicans is probably associated with the HLA-DR6 (DRB1*1301) gene.

Adult↗
PubMed1995

Inhibitory action of hydrogen peroxide on a high-resistance epithelium.

The present study describes the action of H2O2 on active transporting epithelium, and the partial blockade of this action by antioxidants. The addition of increasing concentrations of H2O2 (0.80; 8.0 and 24.0 mmol/l) to the mucosal surface of isolated toad skin causes an irreversible and dose-dependent inhibition of the short circuit current (SCC) and potential difference (PD). Quantitative determination of the parameters of the electrical equivalent circuit of the skin, by means of Isaacson's amiloride test, shows that the most affected parameters were the SCC, PD and shunt conductance. When the skins were preincubated with mannitol and vitamin E, the inhibition elicited by H2O2 was partially blocked; on the other hand, when the skins were preincubated with superoxide dismutase or allopurinol, this inhibition remains unchanged. The thiobarbituric acid method was used as an indirect quantification of lipid peroxidation. The inhibitory action of H2O2 in terms of the equivalent electrical circuit and the parallel production of lipid peroxidation points to free-radical formation. Furthermore, the significant blockade of this action by some enzymatic antioxidants is in agreement with this hypothesis.

Allopurinol↗
PubMed1994

[Geriatric evaluation of elderly patients at a university hospital].

The aim of this work was to evaluate general aspects, medical diagnoses, degree of disability, mental status and social support of hospitalized elders using a Geriatric Assessment Scale, devised at the Catholic University. Ninety eight hospitalized subjects (58 female, aged 60 to 74 years old) were surveyed before discharge. Results showed that 34% had serious handicaps in their daily living and required third party help, 14% had a moderate cognitive impairment and that 12% lacked social or family support. We conclude that the scale is useful, easy to use and allows to obtain a thorough diagnosis of hospitalized elders.

Aged↗
PubMed1994

Raised agalactosyl IgG and antimycobacterial humoral immunity in Takayasu's arteritis.

OBJECTIVE: Takayasu's arteritis is an inflammatory occlusive disease of the aorta and its main branches of unknown etiology. Some suggested causes include inapparent infection with Mycobacterium tuberculosis, or autoimmunity evoked by this organism. We have therefore sought links with mycobacterial disease. METHODS: We assayed the % agalactosyl IgG, antibody to a tuberculosis-specific 38 kDa protein, and antibody to the mycobacterial 65 kDa heat shock protein (HSP), in patients with active or inactive Takayasu's arteritis, in whom the diagnosis of tuberculosis was excluded. The results were compared with findings in tuberculosis (positive controls), normal donors and patients with Wegener's granulomatosis. RESULTS: The % agalactosyl IgG in patients with active arteritis was in the range previously seen only in rheumatoid arthritis, Crohn's disease, and the mycobacterioses. Similarly, significantly raised antibody to the purified 38-kDa protein of M. tuberculosis, and to the 65-kDa HSP of M. leprae, was found in 78% of patients with Takayasu's arteritis, and the levels were higher in those with active disease. CONCLUSION: These results suggest that Takayasu's arteritis particularly clearly illustrates the occasional relationship between mycobacteria and diseases of superficially autoimmune pathogenesis.

Adolescent↗