Biomedical subjects

J Díaz

Publications and source records attributed to J Díaz.

At least 19 recordsLinked to original sources

PubMed2006

Results of the regional intercomparison exercise for the determination of operational quantity HP(10) in Latin America.

Several intercomparison exercises were organised by the International Atomic Energy Agency (IAEA) on the determination of operational quantities at the regional or interregional basis. In the Latin American region an intercomparison for the determination of the operational quantity Hp(10) was completed mid-2004, as a follow-up to previous exercises carried out during the 1990s. Eighteen individual external monitoring services from nineteen Member States participated in the first phase. The second phase grouped 15 services that had participated in the first phase. Dosemeter irradiations in photon beams were done by four Secondary Standard Dosimetry Laboratories (SSDLs) of the region. The preparation of this exercises involved an audit by the IAEA SSDL, where reference irradiations were provided to all participants for verification of their systems. During the first phase (2002-2003) only 9 out of 18 services met the performance requirements for such monitoring services. Necessary corrective actions and procedure verification were implemented. During the second phase (2004) 11 out of 15 services fulfilled the performance criteria. This intercomparison shows that there has been improvement in the second phase and most participants demonstrated a satisfactory performance of the quantity tested.

Body Burden↗

PubMed2006

Distribution of butyltin and derivatives in oyster shells and trapped sediments of two estuaries in Cantabria (Northern Spain).

Distribution of butyltin compounds (BTs) and derivatives (monobutyltin, MBT; dibutyltin, DBT and tributyltin, TBT) was analysed in Crassostrea gigas oyster shells and the sediments trapped in the shell chambers, from two different estuaries in Cantabria (Northern Spain), with very different environmental conditions, where previous data have not been reported. Inorganic tin analysis in oyster shells was performed in order to study the degradation of BTs. Shell thickening and losses in biological growth are related with the presence of TBT, and were determined using three morphological indexes. Total BTs concentrations, expressed as Sn, ranged from 18.0 ng g(-1) to 176.7 ng g(-1) in sediments, and from 2.4 ng g(-1) to 11.1 ng g(-1) in oyster shells. Total inorganic tin concentrations ranged from 1775.0 ng g(-1) to 4781.3 ng g(-1) in oyster shells. The amount of BTs in oyster shells has been associated with the concentrations in the sediments trapped in the shell chambers. Partition coefficients between oyster sediments and oyster shells show the affinity of BTs by the sediments and the higher inorganic tin in oyster shells does not seem to be related to the BTs pollution.

Animals↗

PubMed2006

[Degree of public awareness regarding intensive care units (ICUs) and intensive care physicians in Castilla y León].

AIM: To determine degree of public awareness regarding the activities and health care professionals that comprise intensive care units (ICUs) in the autonomous community of Castilla y León. DESIGN: Questionaire in the form of a true-false test dealing with a) description of an ICU; b) description of ICU patients, and c) degrees and qualifications held by ICU physicians. LOCATION: Waiting rooms of outpatient clinics and ICUs of 9 hospitals in Castilla y León. SUBJECTS AND METHODS: During the period from 1 October 2003 to 29 February 2004, there were surveyed a group of those persons accompanying outpatients arriving for appointments (OP, n = 2,293), and a group comprised of relatives of ICU patients (ICU, n = 727) upon discharge from the ICU. RESULTS: The average age of those subjects surveyed was 45.6 years old. 62.1% were women and 52.8% had received education through secondary level or higher. Of the 1,354 analyzed OP questionnaires, 27.7%, 25.5% and 48.4% responded correctly to questions A, B and C, respectively. Of the 284 analyzed ICU questionnaires, 38.6%, 41.0%, and 63.5% responded correctly to questions A, B and C, respectively. Differences between results from the two surveyed groups were statistically significant, and the best results from the ICU group were found among those subjects whose family members had remained in ICU for 2 days or more. CONCLUSIONS: In the described scope, of the citizens of Castilla y León, 27.7% know as it is a ICU, 25.5% know what type of patients usually is entered there, and 48.4% recognize their doctors like ICU specialists specifically. These knowledge improve significantly after having some relative entered in ICU for more than 2 days.

Adult↗

PubMed2006

Usefulness of acr expression for monitoring latent Mycobacterium tuberculosis bacilli in 'in vitro' and 'in vivo' experimental models.

Real-time RT-PCR was used to quantify the expression of genes possibly involved in Mycobacterium tuberculosis latency in in vitro and murine models. Exponential and stationary phase (EP and SP) bacilli were exposed to decreasing pH levels (from 6.5 to 4.5) in an unstirred culture, and mRNA levels for 16S rRNA, sigma factors sigA,B,E,F,G,H and M, Rv0834c, icl, nirA, narG, fpbB, acr, rpoA, recA and cysH were quantified. The expression of acr was the one that best correlated with the CFU decrease observed in SP bacilli. In the murine model, the expressions of icl, acr and sigF tended to decrease when bacillary counts increased and vice versa. Values from immunodepressed mice (e.g. alpha/beta T cells, TNF, IFN-gamma and iNOs knock out strains), with accelerated bacillary growth rate, confirmed this fact. Finally, the expression of acr was maintained in mice following long-term treatment with antibiotics. The quantification of acr expression could be useful for monitoring the presence of latent bacilli in some murine models of tuberculosis.

Animals↗

PubMed2005

The impact of the summer 2003 heat wave in Iberia: how should we measure it?

We present a new approach to improve the reliability of quantifying the impact of a heat wave on mortality rates. We show, for the recent European summer 2003 heat wave, that the use of absolute maximum temperature values, or number of days above a given threshold, can be misleading. Here, we have assessed the impact of the heat wave on Iberian mortality by applying a four step procedure: (1) calculating, for each observatory, the local maximum temperature (T (max)) distributions, (2) calculating the corresponding 95th percentile values (T (threshold)), (3) locally defining extremely hot days (EHD) as those days on which the local threshold of the 95th percentile of the series is exceeded, and (4) calculating the total degrees-days (DD) of exceedance, by calculating the difference T (max)-T (threshold) and summing these values for all days above T (threshold). We show that the relationship between summer mortality rates and the DD index is non-linear and can be described by a logarithmic function, with a correlation coefficient of 0.78, which explains 60.6% of the mortality variance (F value of 24.64, significant at P<0.0001). Using maximum temperatures, no significant relationship is found with mortality, whereas the EHD frequency shows a significant association with mortality, albeit weaker than that obtained with DD.

Hot Temperature↗

PubMed2005

Impact of urban air pollutants and noise levels over daily hospital admissions in children in Madrid: a time series analysis.

OBJECTIVE: The aim of this paper was to analyse the effects of the urban air pollutants and noise levels on daily emergency hospital admissions of children less than 10 years of age in Madrid. MATERIAL AND METHODS: Poisson Regression Models were used to quantify the associations. Meteorological variables, influenza epidemics, pollen concentrations and trends and periodicities were used as controlling variables. RESULTS: The main results obtained were the detected relationship (p<0.05) between emergency hospital admissions due to organic diseases and noise levels (AR=2.4%) and for PM(10) concentrations (AR=2.1%). For respiratory diseases statistically significant associations were detected for noise levels (AR=4.7%) and cold temperatures (AR=3.8%). The main association detected for causes of admissions due to bronchitis was for O(3) (AR=36.8%) and for pneumonia was for noise levels (AR=7.7%). CONCLUSION: The results obtained suggest that noise level particularly is a risk factor for daily emergency hospital admissions for organic and respiratory diseases in children less than 10 years old in Madrid.

Air Pollutants↗

PubMed2005

Liver transplantation at the Cuban Center for Medical and Surgical Research.

From July 4, 1999, when a liver transplantation program was started in Cuba, to October 2003, 66 procedures had been performed in 60 patients. The most frequent reason was cirrhosis caused by hepatitis C virus (29%), and alcoholic cirrhosis (22%). Two patients received simultaneous liver-kidney transplants. Half of the patients were men. Patient ages ranged from 12 to 62 years; the average surgical time was 6 hours; and cold ischemia time was 4 to 14 hours. The average blood consumption was 2033 mL; 2900 mL of plasma and 8 units of platelets were used in 7 cases. Immunosuppression was mainly cyclosporine (Neoral), mycophenolate mofetil or azathioprine, and prednisone. Acute cellular rejections were treated in almost all cases with 3 doses of methylprednisolone. The most frequent complications were biliary (24%), hepatic arterial thrombosis (12%), post-surgical bleeding (10%), acute cellular rejection (24%), and ductopenic rejection (2%). The overall 1-year survival rate was 73.7%.

Cuba↗

PubMed2005

[Prevention of cardiovascular diseases by an antihypertensive program in the elderly, a cohort study].

INTRODUCTION: We started on year 2000 a Complex Intervention Program addressed at hypertension control among our patients. AIM: To compare the risk of cardiovascular events and of dying in hypertensive patients under Program care. METHOD: We started follow-up of a cohort of 1922 patients over 65 years in August 2000. Hipertension diagnosis was ascertained if patient reported to be hypertensive, or was under anti hypertensive treatment or if he/she had two blood pressure measurements = 140/90 mm Hg. Cardiovascular events were considered to be admissions due to coronary disease, cardiac insufficiency or stroke. Incidence is reported by 100 person years follow-up. Relative risks between hypertensive and normotensive patients were calculated and Cox regresión was used to adjust for potential confounders. We compared time to first cardiovascular event and to death with Log Rank Test. RESULTS: Fourty eight point three percent of patients were hypertensive and differed from normotensive patients as to age (79 (5) years vs. 77 (5) p < 0.001), proportion of diabetic patients (16.1% vs. 7.6% p < 0.001). Mean follow-up time was 28 months. Mortality RR was 1.04 (95% CI 0.69-1.58). As to incidence of cardiovascular events it was 1.86 in normotensive vs. 3.02 (RR 1.62 95% CI 1.09-2.42). When adjusted by age, sex, smoking, dislipemia and diabetes, OR was 1.3 (95% CI 0.86-1.98). CONCLUSIONS: Hypertension did not increase the risk in cardiovascular events among our hypertensive patients at 2.3 years follow-up.

Aged↗

PubMed2004

Selective memory impairment on an adapted Mini-Mental State Examination increases risk of future dementia.

OBJECTIVE: To determine whether selective memory impairment (SMI) on an adapted Mini-Mental State Examination (aMMSE) test increases risk of future dementia in a population-based survey of central Spain. BACKGROUND: SMI is a strong predictor of dementia in the elderly. However, most approaches have used extensive memory batteries, which are not always suitable for screening purposes. METHODS: The basal cohort consisted of 2982 poorly educated individuals aged 65 or over. Dementia, stroke and parkinsonism cases were previously excluded. At entry, participants received a structured interview including an aMMSE. Two groups were created according to basal cognitive performance, namely: (1) aMMSE > 23 and no word remembered on the aMMSE delayed-recall task (SMI group); and (2) aMMSE > 23 and at least one word remembered on the delayed-recall task (control group). In a three-year follow-up wave, conversion rate to dementia was calculated and logistic regression was performed. RESULTS: Of a total of 2507 subjects who completed the two evaluations, 280 qualified for SMI at entry. In the SMI group, 25 subjects (8.9%) developed dementia vs 26 subjects (1.2%) in the control group. Taking the two groups together, and once demographic and medical variables had been controlled, a low delayed-recall score increased dementia conversion rate (OR 0.47, 95% CI 0.34-0.64). Alzheimer's disease was the main cause of dementia (79.8%). CONCLUSIONS: Memory impairment is a risk factor for future dementia in the neurologically-healthy elderly. This can be observed in a subgroup of subjects with SMI defined on the aMMSE delayed-recall subscore. Some other measurements should be added to the SMI construct to improve its predictive validity.

Aged↗

PubMed2004

Impact of temperature and air pollution on the mortality of children in Madrid.

This work analyzes the impact of temperature and air pollution on infant mortality in Madrid. Daily values of mortality of children younger than 10 years, maximum and minimum temperatures, and air pollutants were considered for an 11-year period. In winter, mortality was mostly associated with very low temperatures and high total suspended particles (TSP) concentrations, whereas summer mortality depended crucially on the occurrence of high TSP and nitrogen oxides concentrations. In winter, the temperature effect increases dramatically for daily maximum temperature values lower than 6degreesC. This pattern is rather different from the one obtained for older age groups in the same location, which show the well-known V relationship between temperature and mortality. The association with TSP shows 2 linear branches without threshold and a strong increase in mortality for concentrations more than 100 microg/m3.

Air Pollutants↗

PubMed2003

Relationship between gonadotrophin secretion, inhibin B and spermatogenesis in oligozoospermic men treated with highly purified urinary follicle-stimulating hormone (uFSH-HP): a preliminary report.

PURPOSE: To study the potential relationship between circulating follicle-stimulating hormone (FSH) gonadotrophin, inhibin B, spermatogenesis and the benefit of highly purified urinary FSH (uFSH-HP) treatment in men with oligozoospermia. METHODS: Twenty-nine normogonadotropic, normogonadal men with oligozoospermia were evaluated. Serum hormonal concentration and spermiogram were analyzed before and after 3-month treatment with uFSH-HP. RESULTS: Our results support the hypothesis that inhibin B is involved in the physiological regulation of FSH secretion and reflects the FSH-stimulated Sertoli cell function. After treating with uFSH-HP for 3 months a significant increase in all semen parameters was observed in most of the patients. CONCLUSIONS: Although the benefit of inhibin B as a prognosis factor in oligozoospermic patients treated with FSH is not defined, it can be considered as an important serum marker in reproductive and testicular functions. Treatment of oligozoospermic patients with uFSH-HP has shown to be an effective and safe therapy.

Adult↗

PubMed2003

Effect of a low-dose oral contraceptive containing 20 microg ethinylestradiol and 150 microg desogestrel on dysmenorrhea.

This observational study evaluated the effect of a low-dose oral contraceptive (OC), containing 20 mug ethinylestradiol and 150 mug desogestrel (20EE/150DSG) on dysmenorrhea. Of the 346 women enrolled, 301 (87%) completed the three-cycle study. All participants (mean age: 22.6 years) wished to use oral contraception and had dysmenorrhea for at least 3 months. Dysmenorrhea was assessed using both the adapted verbal multidimensional scoring system (VMSS-A) and a visual analogue scale (VAS) to rate pain intensity. General dysmenorrhea symptoms and the use of analgesics were also assessed. The mean total combined scores on the VMSS-A scale decreased from 5.4 to 1.4 (p < 0.001), during the three cycles of OC use. The mean VAS pain-intensity score decreased from 6.8 to 1.8 (p < 0.001). During treatment there were substantial improvements in most individual parameters of dysmenorrhea. The percentage of women with dysmenorrhea lasting > or =2 days decreased from 81% at baseline to 14% at cycle 3. The percentage of women reporting generalized dysmenorrhea symptoms (e.g., lumbago, asthenia) decreased from 79% to 21% and the percentage needing analgesics dropped from 100% to 41%. The percentage of women for whom dysmenorrhea interfered with daily activities decreased from 73% to 10%. The results indicate that 20EE/150DSG can statistically and clinically significantly reduce the incidence and severity of dysmenorrhea, and its impact on daily activities.

Activities of Daily Living↗

PubMed2003

Use of recombinant human erythropoietin in kidney transplant patients with stable graft function.

The purpose of this work was to determine the necessity for rhuEPO for 50 kidney transplant patients with stable graft function. We analyzed the red cell series, blood pressure, renal function, anthropometric data of the donor and recipient, proteinuria, and relationship with other factors, including immunosuppressants, angiotensin converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB). The patients were divided into three groups depending on renal function: group A (with plasma creatinine <150 micromol/L), group B (151-250 micromol/L), and group C (>250 micromol/L). All patients were studied for 1 year. Erythropoietin use did not affect renal function, proteinuria or number of antihypertensive drugs group. The degree of renal dysfunction determined the time necessary to reach an adequate hemoglobin level (>12 g/L) and and the mean dose of weekly rhuEPO needed. The use of ACE inhibitors or ARBs increased the rhuEPO requirements in each group.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed2003

A simple noninvasive pressure-time index at the mouth to measure respiratory load during acute exacerbation of COPD A comparison with normal volunteers.

We assessed the validity of the pressure-time index (PTI) measured at the mouth as a noninvasive and simplified alternative to conventional tension-time index for assessing respiratory load and inspiratory muscle force reserve. PTI was measured within 48 h of hospital admission and at 24 h before discharge in 37 consecutive patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) using the equation PTI = (P(awo)/MIP)(T(I)/T(T)) 100, where P(awo) is the mean airway pressure measured at the mouth, MIP the maximal inspiratory pressure, and T(I)/T(T) the inspiratory time (T(I)) to total cycle length (T(T)) ratio. Controls were 30 normal volunteers with similar anthropometric features. Mean (+/- SD) PTI values were significantly higher in COPD patients (0.29 +/- 0.10) than in controls (0.11 +/- 0.04) (P < 0.001) primarily because MIP and T(I)/T(T) were significantly lower and P(awo) was higher in the COPD population than in controls. As a result of improvement of the respiratory condition, PTI values were significantly lower at discharge (0.20 +/- 0.10 vs. 0.29 +/- 0.10, P < 0.001) due to a drop in P(awo) and an increase in MIP. The accuracy of different PTI cutpoints was assessed by comparison of the receiver operating characteristics curves. Best cutpoint values for differentiating COPD patients on admission and at hospital discharge from controls were 0.13 (positive predictive value 76%) and 0.17 (positive predictive value 92%) respectively. Noninvasive PTI measured at the mouth provides a valid and easy method for assessing respiratory muscle load and reserve. Changes in PTI values reflect functional improvement following treatment of acute exacerbation of COPD.

Aged↗

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

Suppression of soft nuclear bremsstrahlung in proton-nucleus collisions.

Photon energy spectra up to the kinematic limit have been measured in 190 MeV proton reactions with light and heavy nuclei to investigate the influence of the multiple-scattering process on the photon production. Relative to the predictions of models based on a quasifree production mechanism, a strong suppression of bremsstrahlung is observed in the low-energy region of the photon spectrum. We attribute this effect to the interference of photon amplitudes due to multiple scattering of nucleons in the nuclear medium.

Journal Article↗

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

Copper metabolism and biliary secretion in patients receiving orthotopic liver transplantation.

BACKGROUND: The quantitative aspects of biliary copper excretion in health and disease have not been fully defined yet. The aim of the study was to evaluate copper metabolism and biliary excretion of patients who have received an orthotopic liver transplant (OLT) during the immediate postoperative period. METHODS: We have studied retrospectively 16 patients undergoing primary OLT and eight undergoing cholecystectomy, and measured serum concentration of copper and its secretion in bile and urine by flame atomic absorption spectrometry (FAAS). RESULTS: We found a progressive increase of biliary copper secretion rates and a corresponding lowering of urinary copper during the postoperative period. Thus, in OLT patients, the mean of biliary copper secretion on day 1 is 0.7+/-0.2 micromol/day compared with 2.3+/-1.1 micromol/day on day 7 (p<0.01) and 6.1+/-2.5 micromol/day on day 15 (p<0.0001). The rate of copper output on day 5 after surgery is about one sixth of the value reported for patients who had undergone cholecystectomy. In patients suffering an acute rejection episode, there was an abrupt fall in bile flow (<15 ml/day) and excretion of biliary copper (<1 micromol/day), accompanied by an increase of urine copper excretion (>3 micromol/day), and both were recovered when the rejection episode was solved. We found an inverse relationship between the serum bilirubin (Bt), alkaline phosphatase (ALP) and the biliary copper excretion (p<0.01), and a direct relationship with urinary copper excretion (p<0.01). CONCLUSIONS: The copper measurements in urine and bile are non-invasive techniques, of low cost, rapid and easy to accomplish, and available in hospitals accredited for hepatic transplantation. These characteristics make these methods helpful in the monitoring of patients submitted to OLT for assessment of graft quality and subsequent outcome.

Adult↗