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Biomedical subjects

R García

Publications and source records attributed to R García.

At least 19 recordsLinked to original sources
PubMed2004

Quantification of the major allergen from cypress (Cupressus arizonica) pollen, Cup a 1, by monoclonal antibody-based ELISA.

BACKGROUND: Cypress pollen allergy is an important cause of rhinoconjunctivitis and asthma in Mediterranean countries. Cypress allergenic extracts are difficult to produce since they have low protein and high carbohydrate content, thus accurate standardization of them is essential to guarantee their quality. The aim of this study is to develop a sandwich ELISA for the quantification of Cup a 1, the major allergen of cypress (Cupressus arizonica) pollen extract. METHODS: Monoclonal antibodies directed to purified Cup a 1 were produced. Two of them (9C7 as capture antibody and 3D2 as the tracer) were selected to develop a quantitative sandwich ELISA. This ELISA was subsequently evaluated and compared with other techniques. RESULTS: The described ELISA is very sensitive with a detection limit of 8.7 ng/ml and a practical working range of 62.5-1,000 ng/ml. The assay is also highly reproducible with intra-assay and interassay coefficients of variation of less than 10%. The purified Cup a 1, used as standard, presents pectate lyase enzymatic activity. The assay also detected Cup a 1-like proteins in pollen from other Cupressaceae. A good correlation was obtained between Cup a 1 content of 12 C. arizonica pollen extracts and their IgE-binding activity. CONCLUSIONS: The described Cup a 1 ELISA is sensitive, specific and reproducible and can be used for the quantification of Cup a 1 in C. arizonica and other related pollen extracts. It also provides a reliable indication of the allergenic activity of the whole cypress pollen extract.

Allergens↗
PubMed2004

Outcome of children with B cell lymphoma in Venezuela with the LMB-89 protocol.

BACKGROUND: We analyzed the results of the LMB-89 protocol performed in seven centers in Venezuela in 96 children having B-cell non-Hodgkin lymphoma treated from 1995 to 2002. PROCEDURE: Mean age was 7.1 years with 71 (74%) been male. Eighty-two patients (85%) had diffuse small cell lymphoma Burkitt and Burkitt-like, and 14 (15%) had diffuse large B-cell lymphoma. Initial disease sites included the abdomen in 67%, peripheral nodes in 8%, and mediastinal in 4%. Treatment was directed to risk groups as described for LMB-89 protocol. Group A: seven patients (7%), group B: 80 patients (83%), and group C: nine patients (9%). RESULTS: Mean follow-up was 35 +/- 31 months. Complete remission (CR) occurred in 70 patients (73%); four patients (6%) had relapse during the first year and ten patients (10%) had progressive disease. Overall survival (OS) and event free survival (EFS) were 85 and 80% at 1 year, and 82 and 75% at 2 years, respectively. The EFS by therapeutic groups at 3 years was A: 100%; B: 76%, and C: 56%. TOXICITY: neutropenia in 75%, thrombocytopenia in 63%, febrile neutropenia in 39%. Viral infections: hepatitis B in 20%, hepatitis C in 2%, and Herpes zoster in 3%. Tumor lysis syndrome (TLS) occurred in 9% during induction phase with a high mortality of 44% (urate-oxidase was available only at the end of the study). CONCLUSIONS: The high mortality rate during induction phase prohibited a better EFS. Prophylactic use of xantine-oxidase may improve future results. The high incidence of hepatitis B requires a vaccination program.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2003

A superconducting reversible rectifier that controls the motion of magnetic flux quanta.

We fabricated a device that controls the motion of flux quanta in a niobium superconducting film grown on an array of nanoscale triangular pinning potentials. The controllable rectification of the vortex motion is due to the asymmetry of the fabricated magnetic pinning centers. The reversal in the direction of the vortex flow is explained by the interaction between the vortices trapped on the magnetic nanostructures and the interstitial vortices. The applied magnetic field and input current strength can tune both the polarity and magnitude of the rectified vortex flow. Our ratchet system is explained and modeled theoretically, taking the interactions between particles into consideration.

Journal Article↗
PubMed2003

Tacrolimus in induction immunosuppressive treatment in renal transplantation: comparison with cyclosporine.

The aim of the study was to compare the efficacy and safety of induction immunosuppression therapies based on tacrolimus or cyclosporine (CsA) in kidney transplantation. The 240 kidney allograft recipients were divided into two groups: group 1 (n=94) received tacrolimus (.01 mg/kg per day), mycophenolate mofetil (MMF, 2 g/d), and steroids (30 mg/d); and group 2 (n=146) CsA (6 mg/kg per day), MMF (2 g/d), and steroids (30 mg/d). Antilymphocyte serum was administered in cases of acute tubular necrosis. The acute rejection rate was higher among group 2 (30.6%) compared with group 1 patients (12.2%) (P=.001). There were no significant differences between the groups in terms of age, gender, body surface area, serologic virus markers (in donor and recipient), baseline creatinine levels, cause of death, HLA incompatibilities, response to acute tubular necrosis, and number of dialysis sessions. We conclude that both immunosuppressive regimens are effective and safe in kidney transplantation. The survival rates of patients and grafts were similar, but the incidence and degree of acute rejection events were reduced in group 1; this finding may forecast a decreased incidence of chronic renal allograft nephropathy.

Adrenal Cortex Hormones↗
PubMed2003

Severely elevated intrarenal arterial impedance and abnormal venous flow pattern in a normal functioning kidney graft.

Serial Doppler sonographic impedance measurements represent the most common diagnostic method for noninvasive monitoring of kidney grafts. Severely elevated arterial impedance is almost always associated with graft dysfunction. However, we describe in the present work a renal transplant recipient with optimal graft function despite permanently elevated arterial impedance (pulsatility index (PI) ranging from 2.9-3.0, and resistive index (RI) = 1.0 as well as an abnormal venous flow pattern. In contrast, the contralateral graft from the same cadaver donors transplanted into a 17-year-old female patient displayed normal range PI and RI values in conjunction with a normal serum creatinine. Known causes of arterial impedance elevation such as rejection, cyclosporine, urinary obstruction, and external graft compression were excluded. Other extrarenal causes of high impedance, such as aortic insufficiency and reduced aortic compliance, were also excluded. No evidence of impaired venous outflow at the site of the anastomosis of the main renal vein to the iliac vein was found. Those findings support the view that impedance indexes are hemodynamic rather than functional parameters.

Adolescent↗
PubMed2003

Significance of cytomegalovirus infection in renal transplantation.

The aim of this study was to establish the relationship between vascular lesion chronic allograft nephropathy (CAN) and the presence of cytomegalovirus (CMV) in kidney transplanted patients. We studied 259 consecutive kidney transplant recipients with a minimum follow-up of 6 months; the induction immunosuppressive therapy included a calcineurin inhibitor, mycophenolate mofetil, steroids, and the use of an antilymphocyte serum if the patients developed delayed graft function. CMV early antigen detection (pp65) was performed on a weekly basis between days 30 and 90 post transplantation. Prophylactic treatment was administered in the donor +/recipient-risk group, and preemptive therapy delivered for positive antigenemia namely 3 days of intravenous [IV] gancyclovir [GCV] plus 11 days of oral therapy [in the case of infection], or 14 days of IV GCV [in the case of disease]). An acute kidney allograft rejection episode preceded CMV in 64.3% of the patients, and CMV preceded acute rejection in 35.7% of the cases. We conclude that CMV disease is an independent risk factor for CAN. CMV infection is probably associated with CAN, suggesting that the greater the viral load, the higher the risk of CAN. It may be advisable to perform universal prophylaxis to lower the viral load and CAN.

Cytomegalovirus Infections↗
PubMed2003

Osteoarticular pain and bone mineral density in renal transplantation.

INTRODUCTION: The reduction of bone mineral density (BMD) levels is an important complication after renal transplantation. The prevalence of nontraumatic lesions may reach 22%. Patients with lower osseous mass suffer the highest number of lesions. OBJECTIVE: Evaluate BMD in patients over 30-years old who have undergone renal transplantation more than 1 year prior, who attend a medical facility complaining of osteoarticular pain and were prescribed rest or any analgesia. PATIENTS AND METHODS: One hundred twenty-three patients who received a renal transplant from a cadaveric donor from 1980 through 2000 were included in the present study to measure BMD levels in the hips and the vertebral column using a densitometer (Hologic 4500 QDR). Our study complied with WHO recommendations, which define normal values as a T score >-1 SD osteopenia as a (T score between <-1 and >-2.5 SD), and osteoporosis as a T score <-2.5 SD. Patients were divided into three groups according to gender and hormonal status. The following clinical and analytic data were collected: age, gender, race, age at onset of menopause, diabetes mellitus (DM), weight, size, retransplantation, period of evolution after transplantation, and parathormone (PTH), creatinine, and renal clearance values. RESULTS: There were 51 men (41.1%) included. Forty postmenopausal (32.5%) and premenopausal women (26%) were also included. In all patients we observed a correlation between a reduction in BMD values and age, duration post-transplantation, and body weight (P<.05). Reduced BMD levels in premenopausal women were related with lower body weight, (P<.05) and elevated PTH levels (P<.024). CONCLUSIONS: We observed that patients who had undergone transplantation displayed a moderately higher risk of suffering a fracture. Such risk increased in the case of women with more frequent fractures in the vertebral column. In 23.8% of patients reporting osseous pain, there was no reduction in BMD levels. Therefore, we must look for other disorder, responsible for the pain and prescribe adequate treatment.

Adult↗
PubMed2003

Rat glomerulosa cells in primary culture and E. coli lipopolysaccharide action.

During endotoxic shock there is a dysfunction of the adrenal gland; both corticosterone and aldosterone secretion are altered. The aim of the present study is to use glomerulosa cells in primary culture as a target of lipopolysaccharide (LPS) action. Glomerulosa cells cultured in basal conditions are able to proliferate; bFGF and ACTH have antagonic effects, bFGF increases proliferation whereas ACTH is antimitogenic. LPS has a biphasic effect, in the short term it is antimitogenic and in the long term increases the proliferation rate. LPS inhibits ACTH-induced corticosterone secretion in a dose-dependent manner in glomerulosa cells in culture similar to that in fasciculata cells, but it does not exert an important direct effect on aldosterone secretion. These results show that LPS exerts different effects in ACTH and ANG II signal transduction pathways and in the two enzymes which catalyze the late step in the steroidogenesis, 11beta-hydroxylase and aldosterone synthase, which could be in agreement with the existence of both enzymes, regulated independently, in rat zona glomerulosa cells.

Adrenocorticotropic Hormone↗
PubMed2003

Textile dyeing wastewater treatment in a sequencing batch reactor system.

This study was undertaken to examine the feasibility of treating biologically textile wastewater for organic carbon removal. The study was conducted over a lab scale SBR equipped with an in-house developed data acquisition and control software. From monitored operation of SBR and dissolved oxygen values, together with a simple compressed air ON/OFF control scheme, on-line Oxygen Uptake Rate (OUR) profiles during aerobic reaction periods were obtained. Due to the high variability of wastewater characteristics, periodical analyses of textile wastewater were conducted and thus characterized for pH, conductivity, total and volatile solids, COD, ammonia, and TKN. After an initial period of activated sludge adaptation to textile wastewater, the SBR was operated at step-feed strategy to reduce the effluent biodegradable matter presents in the wastewater by SBR water change ratio modification and feeding strategy.

Automation↗
PubMed2003

O/W microemulsions for oral drug delivery.

Quaternary microemulsion compositions for oral administration using isopropyl myristate, polysorbate 80 and ethanol 96 degrees were developed and three ratio of polysorbate to ethanol were selected. Isotropic single-phase compositions were considered as microemulsions and were registered on a Pseudo-Ternary Phase Diagram. The objective was to formulate a therapeutic dose for lorazepam and loperamide in a drop liquid form. Another aim was to obtain a liquid oral formula for nifedipine taking advantage of its insured fast absorption to be used in hypertensive crises. The physical stability of the compositions was evaluated by normal aging, centrifugal resistance time and by cycling as well. The selected formulation characterization included density, pH and conductivity measurements. The particle size distribution was determined by a light scattering method and, finally the carried drugs concentration was valued. The versatility showed by this type of systems allows both to carry drugs of different physico-chemical properties and to deal with a number of pharmacotherapeutic objectives.

Administration, Oral↗
PubMed2002

Capillary electrophoretic analysis of inorganic anions in atmospheric hailstone samples.

A new application of capillary electrophoresis (CE) for measuring inorganic anions in hailstones was carried out. Five hailstone specimens were collected from large blocks of ice that fell in January 2000 in some provinces of Spain. Sample handling and preparation procedures were performed with care. CE analysis of anions was carried out using indirect UV detection at 254 nm with a negative power supply (-15 kV) and hydrostatic injection (10 cm for 30 s) at 35 degrees C. Anion separation was completed in less than 4 min. The working electrolyte consisted of 4.7 mM sodium chromate, 4.0 mM OFM-OH (tetradecyltrimethylammonium hydroxide), 10 mM CHES [2-(N-cyclohexylamino)ethanesulfonic acid], and 0.1 mM calcium gluconate (pH 9.1). Good repeatability of migration times after eight injections (<0.7% RSD), adequate linearity responses (r2>0.9) as well as satisfactory detection limits (<0.35 ppm) were achieved. The analytical results provided by CE were compared with those obtained by traditional wet-chemical (WCH) methods. Most of the results obtained by CE were consistent with those of WCH, except for one sample.

Anions↗
PubMed2002

Effects of extremely hot days on people older than 65 years in Seville (Spain) from 1986 to 1997.

The effects of heat waves on the population have been described by different authors and a consistent relationship between mortality and temperature has been found, especially in elderly subjects. The present paper studies this effect in Seville, a city in the south of Spain, known for its climate of mild winters and hot summers, when the temperature frequently exceeds 40 degrees C. This study focuses on the summer months (June to September) for the years from 1986 to 1997. The relationships between total daily mortality and different specific causes for persons older than 65 and 75 years, of each gender, were analysed. Maximum daily temperature and relative humidity at 7.00 a.m. were introduced as environmental variables. The possible confounding effect of different atmospheric pollutants, particularly ozone, were considered. The methodology employed was time series analysis using Box-Jenkins models with exogenous variables. On the basis of dispersion diagrams, we defined extremely hot days as those when the maximum daily temperature surpassed 41 degrees C. The ARIMA model clearly shows the relationship between temperature and mortality. Mortality for all causes increased up to 51% above the average in the group over 75 years for each degree Celsius beyond 41 degrees C. The effect is more noticeable for cardiovascular than for respiratory diseases, and more in women than in men. Among the atmospheric pollutants, a relation was found between mortality and concentrations of ozone, especially for men older than 75.

Aged↗
PubMed2002

Suppressed ion chromatography for monitoring chemical impurities in steam for geothermal power plants.

A suppressed ion chromatography (IC) technique has been evaluated as a chemical monitoring tool for detecting major anions (F-, Cl-, NO3- and SO4(2-)) of condensed steam in geothermal power plants. It is shown that the suppressed IC technique provides a suitable means for preventing possible damage to generating equipment in the geothermal industry. An electrical conductivity detector (0.1 microS sensitivity) with an anion-exchange column (IonPac AS4A-SC), a micro-membrane suppressor (AMMS II), and an isocratic high-pressure pump system were successfully used for detecting low concentrations of inorganic anions. Method detection limits for the anions of interest were <0.184 mg/L. Details of the IC methodology as well as some experimental results obtained during its application for the chemical monitoring of geothermal steam pipes are also described.

Chromatography, Ion Exchange↗
PubMed2002

Heat waves in Madrid 1986-1997: effects on the health of the elderly.

OBJECTIVE: The objective of this paper is to analyse and quantify the effects exerted on summer mortality by extremes of heat, particularly among persons aged 65-74 and 75 years and over, groups in which mortality is higher. METHODS: The study included the period from 1 January 1986 to 31 December 1997, for all people aged over 65 years resident in Madrid, based on mortality due to all causes except accidents (ICD-9 codes 1-799), and circulatory (390-459) and respiratory (460-487) causes. Meteorological variables analysed were: daily maximum temperature, daily minimum temperature and relative humidity. To control the effect of air pollution on mortality we considered the daily mean values of sulphur dioxide (SO2), total suspended particulate (TSP), nitric oxides (NOx), nitrogen dioxide (NO2) and tropospheric ozone (O3). Univariate and multivariate ARIMA models were used. Box-Jenkins pre-whitening was performed. RESULTS: The results yielded by this study indicate a mortality increase up to 28.4% for every degree the temperature rises above 36.5 degrees C, with particular effect in women over the age of 75 years and circulatory-cause mortality. The first heat wave that leads to the greatest effects on mortality, due to the higher number of susceptible people and the duration of the heat wave, show an exponential growth in mortality. Furthermore, low relative humidity enhances the effects of high temperature, linking dryness to air pollutants, ozone in particular. CONCLUSIONS: Since a warmer climate is predicted in the future, the incidence of heat wave should increase, and more comprehensive measures, both medical and social, should be adopted to prevent the effects of extreme heat on the population, particularly the elderly.

Aged↗
PubMed2002

[Massive bilateral adrenal hemorrhage after conservative tumor surgery in the isthmus of a horseshoe kidney].

OBJECTIVE: To present a fatal case of massive bilateral suprarrenal haemorrhage (MBSH) after partial nephrectomy. CLINICAL CASE: An 82 year old male treated with oral anticoagulants was diagnosed by means of CT scan and arteriography of having an avascular tumor located at the isthmus of a horseshoe kidney. A tumorectomy with safety surgical margins was performed; It was diagnosed of having a renal adenocarcinoma, which was almost completely necrotic. During the postoperative period, the patient presented abdominal pain, nausea, fever, hypotension and severe respiratory distress. Biochemical studies showed mild hyponatremia and azotemia, accompanied by anemia, leucocytosis and thrombocytosis. An abdominal CT scan demonstrated a MBSH, which produced the patients death soon afterwards. DISCUSSION: Tumoral pathology of horseshoe kidneys presents important topographic and anatomopathologic differences with respect to non-fused kidneys. MBSH is a rare complication of many stress processes especially if an anticoagulant treatment coexists. The treatment has to be initiated as soon as we suspect MBSH, which should be confirmed by hormonal determinations and/or the presence of hyperdense suprarenal lesions at the CT scan.

Adenocarcinoma↗
PubMed2002

Enzymatic esterification of an acid with an epoxide using an immobilized lipase from Mucor miehei as catalyst: optimization of the yield and isomeric excess of ester by statistical analysis.

We have developed the methodology for the esterification of an acid with an epoxide using 2-chlorobutyric acid and 1,2-epoxy-5-hexene catalysed by a Mucor miehei-immobilized lipase. Thus, this methodology could be applied to obtain 2-chloroesters. A factorial design of experiments and a central composite design have been used to optimise the synthesis of these esters. The variables chosen were temperature and initial catalyst concentration, while the responses were yield and isomeric excess of the ester. According to this study, temperature was the most important factor, having a positive influence on the yield and a small negative influence on the isomeric excess of the ester. The yield and isomeric excess of the ester show a greater dependence on temperature compared to the catalyst concentration. Although the effect of the catalyst concentration on both responses is smaller than the temperature effect, the higher selectivity presented by the biocatalyst towards the studied ester considerably decreased the final product distribution.

Acids↗
PubMed2002

[Analysis of survival in dialysis: hemodialysis versus peritoneal dialysis and the significance of comorbidity].

To choose the best possible dialysis technique for those patients with end-stage renal disease continues to be a matter of debate. Even after putting aside the evident influence that economic and geographic factors as well as the health politics may have in the selection of the technique, different studies comparing survival between hemodialysis (HD) and peritoneal dialysis (PD) have shown contradictory results which could be explained by the differing methodological and statistical methods used together with the different influence assigned to the comorbidity found when starting the treatment, a situation that has increased the confusion about this topic. Based on this we performed a retrospective analysis with a follow-up time of seven years including all those patients who started dialytic treatment in our area, with a final number of 3.106 hemodialysis patients and 542 peritoneal dialysis patients. Those patients who were transferred to another treatment technique during the time of the study were excluded. Age higher than 70 years, cardiovascular disease, liver disease, diabetes mellitus and the presence of dyslipidemia were included as comorbidity factors. Peritoneal dialysis patients were younger than those treated by hemodialysis (54.53 vs 60.1 years), but suffered from higher cardiovascular comorbidity and were more often diabetic. The global survival was the same in both groups up to 32 months of treatment. Although no differences were found when comparing those patients without comorbidity factors, those with comorbidity had better survival on hemodialysis. Age higher than 70 years was the only comorbidity factor with statistically significant difference for a better survival in hemodialysis.

Adolescent↗