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Biomedical subjects

I Pastor

Publications and source records attributed to I Pastor.

At least 19 recordsLinked to original sources
PubMed2006

Charge transport in luminescent polymers studied by in situ fluorescence spectroscopy.

Modulation of the photoluminescence of poly-[2,7-(fluorene)-1,4-(phenylene)] can be attained by reversible electrochemical modification of the conjugated chain (p- or n-doping). Controlled injection of charge quenches the fluorescent emission of the conjugated polymer. The injection of holes completely eliminates the emission, while the electrons only quench up to one-third of the initial fluorescence of the polymer. Analogous quenching effects have been previously reported for solid-state organoelectronic devices. Electrochemical Stern-Volmer plots permit the estimation of the relative mobility of charge carriers in the polymer layer. The mobility of holes is 1 order of magnitude higher that the mobility of electrons, as determined by this method.

Electrochemistry↗
PubMed2004

Application of receiver operating characteristics curve (ROC) analysis when definitive and suspect morphologic flags appear in the new Coulter LH 750 analyzer.

Workflow efficiency is important in every laboratory. Manual assessment of white blood cell counts and differentials that have been rejected by an automated analyzer is one of the most time-consuming tasks in the routine hematology laboratory. In this study, receiver operating characteristics (ROC) curve analysis was used for the first time when anomalous distribution and suspect flag alarms appeared in hemograms carried out with the new Beckman Coulter LH 750 analyzer. This article is our second about the LH 750 analyzer published in this journal; we increased the number of cases and describe the novel application of statistical analysis of ROC curves. In processing of specimens from patients with 3% to 6% immature granulocytes (myelocytes + metamyelocytes + bands ), the suspect flag Imm Ne 1 (immature granulocytes) showed 77% diagnostic efficiency with a maximum area under curve (AUC) of 0.71 and a 95% confidence interval (CI) of 0.597 to 0.831 without significant differences between the 3 available levels of alarms in the analyzer (L1, L2, L2). In processing of specimens from patients with >6% immature granulocytes, the Imm Ne 1 flag showed superior diagnostic efficiency of 98% with a maximum AUC of 0.80 and a CI of 0.713 to 0.879. The suspect flag Imm Ne 2 in processing of specimens from patients with >6% of immature granulocytes showed diagnostic efficiency of 92% with a maximum AUC of 0.77 and a CI of 0.665 to 0.871, finding a significant positive difference in level L3 regarding sensitivity in comparison with the other 2 levels of the analyzer (L1, L2). For specimens from patients with >2% blasts, the suspect Blasts alarm showed a diagnostic efficiency of 94%, an AUC of 0.91, and a CI of 0.775 to 1.043; positive differences were observed between the levels L2/L3 and L1. In processing of specimens with variant lymphocytes (large, granular, prolymphocytes, cleaved, chronic lymphocytic leukemia type, and so forth) >10% (x = 14%), the suspect alarm Var Lym (variant lymphocytes) showed a low diagnostic sensitivity of 20% with a maximum AUC of 0.59 and a CI of 0.300 to 0.870 without significant differences between the 3 available levels (L1, L2, L3). However, in processing of specimens presenting values >10% reactive or activated lymphocytes (x = 23%), typical for patients with infectious mononucleosis, the Var Lym flag showed a superior sensitivity of 75% with a diagnostic efficiency of 92% and an AUC of 0.84 with a CI of 0.587 to 1.089. Finally, the laboratory can easily program definitive abnormal morphological flags of distribution (granulocytosis, eosinophilia, monocytosis, and so forth) on the basis of its patient population. In this study we were able to carry out comparisons of AUC and to choose the values for the automated counts in percentage, absolute value, or both. Therefore we were able to define the reliability and impact on the alarm routine to optimize the performance of the user-adjustable definitive alarms for anomalous distribution.

Adult↗
PubMed2003

The contribution of modern imaging to planning separation strategies in conjoined twins.

BACKGROUND/AIM: An accurate knowledge of the often complex and unexpected anatomy of conjoined twins is required in order to devise appropriate surgical strategies for separation. The recent progress of imaging techniques prompts an assessment of their contribution to planning separation strategies. MATERIAL AND METHODS: From 1990, we treated 8 consecutive sets of conjoined twins: 1 acardiac-acephalus, 1 epigastric heteropagus, 2 omphalopagus, 2 omphalothoracopagus, 1 ischiopagus tetrapus and 1 parapagus tripus. The first two sets were separated straightforwardly after birth and were excluded. Ultrasonographic and plain and contrast X-ray studies were used in all the remaining sets, angiography in 5, CT in 4, and MRI in 4. Helical CT and magnetic resonance angiography (MRA) were used in 3 sets. RESULTS: Two sets of omphalopagus twins and one of omphalothoracopagus twins were separated after birth due to brain damage of one twin, cloacal exstrophy and large arterial shunting, respectively. They were assessed using barium studies (3 sets), IVP (3), angiography (2), CT (2) and MRI (1). Three of six babies survived after separation. In the second set of omphalothoracopagus ecocardiography and MRA revealed that the extent of cardiovascular sharing precluded separation. In the remaining two sets of twins respectively ischiopagus and parapagus, the extent of organ sharing was depicted using three-dimensional helical CT and MRI; the four babies are alive after separation. CONCLUSIONS: Conventional imaging contributes only modestly to separation planning. In contrast, advanced imaging techniques are amazingly efficient in depicting complex fusions that have to be accurately recognised when planning realistic separation strategies.

Female↗
PubMed2003

Validation of the Coulter LH 750 in a hospital reference laboratory.

Validation of the Coulter LH 750 was carried out in our central hospital laboratory, which processes 1500 hemograms per day for patients admitted into the 4 hospitals of our hospital complex and their corresponding outpatient departments. It is the reference laboratory for the provincial health care area. The analytical quality and the practical use of the instrument were studied, and we obtained within- and between-run imprecision estimates with reference controls of between 0.24% and 2.56% and inaccuracies of between -1.32% and 3.07% for basic hemogram parameters. Similar results were obtained with specimens from patients, with imprecision estimates between 0.56% and 2.56%. Linearity estimates were between 0.3 x 10(9)/L and 380 x 10(9)/L for leukocytes and between 3 x 10(9)/L and 1900 x 10(9)/L for platelets. The instrument evaluation was completed with a study of interference by bilirubin, lipemia, hemolysis, platelet clumps, and heparin and an examination of other variables, including carryover, detection limits, and the correlation of results with those of the Coulter Gen-S. A special evaluation was made of the new erythroblast count feature; with reference controls, imprecision estimates for this count were 10% to 12%, and with patient specimens imprecision averaged 10.39% up to 4 erythroblasts per 100 leukocytes. We also studied the correlation of LH 750 results and interferences with those of the manual reference method. Finally, National Committee for Clinical Laboratory Standards protocols were used to test for suspect and confirmation flags in leukocyte differential counts for 258 specimens representative of our routine. The practicability of the analyzer was studied in terms of technical difficulty, speed, and cost; also evaluated were new software elements for validation by source clinic and pathology and for reference values based on age. In conclusion, we analyzed the impact and improvements that may be expected in our laboratory (a user of Technicon and Coulter instruments) from introducing the new LH 750 analyzer into our routine.

Blood Cell Count↗
PubMed2000

Profile structures of TJ-II stellarator plasmas

Fine structures are found in the TJ-II stellarator electron temperature and density profiles, when they are measured using a high spatial resolution Thomson scattering system. These structures consist of peaks and valleys superimposed to a smooth average. Some irregularities remain in an ensemble average of discharges with similar macroscopic parameters such as line density, central temperature, and plasma current. They are found in all the magnetic configurations explored in plasmas heated by electron cyclotron waves. Their characteristics are shown and their possible origin is discussed.

Journal Article↗
PubMed2000

Alcoholic liver cirrhosis is associated with a decreased expression of the CD28 costimulatory molecule, a lower ability of T cells to bind exogenous IL-2, and increased soluble CD8 levels.

Despite the existence of high interleukin (IL)-12 serum levels in patients with chronic active alcoholism, previous studies from our group have shown that, during active ethanol intake, alcoholic patients with alcoholic liver cirrhosis (ALC) display an impaired T-helper-1 response together with abnormalities in the peripheral blood (PB) cytotoxic compartment. The aim of the present study was to gain further insights into the mechanisms underlying these abnormalities. For that purpose, we analyzed the expression on PB B- and T-cell subsets of both the CD28 and CD80 costimulatory molecules, the ability of T lymphocytes to bind to exogenous recombinant IL-2, and the serum levels of soluble CD8 (sCD8) that might interfere with CD8+ T-cell activation in a group of 10 ALC patients with active ethanol intake (ALCET group). As reference groups, we analyzed 10 healthy individuals, 10 chronic alcoholic patients without liver disease (AWLD group) but with active ethanol intake, and 10 ALC patients who had quit drinking for at least 1 year. Our results showed that ALCET patients display a significant decrease in the number of PB CD28+/CD8(hi) T cells (P < 0.05) and CD80+ B cells (P < 0.01) compared with both healthy controls and AWLD patients. In addition, in ALCET patients, PB T cells also showed a decreased ability to bind to exogenous IL-2 (P < 0.01). This was associated with the existence of increased serum levels of sCD8 in ALC patients, the highest levels being detected in the ALCET group (P < 0.01). Altogether, our results point to the existence of several abnormalities that would affect the cytotoxic response in ALCET patients.

Adult↗
PubMed2000

Atopy and pulmonary function abnormalities in children with a history of acute bronchiolitis.

To assess the relationship between acute viral bronchiolitis and subsequent development of asthma, we studied retrospectively 97 index children, aged between 9 and 14 years, and 52 controls. The bronchiolitis group showed significantly lower values for mean expiratory flow at 50% of vital capacity (MEF50) higher incidence of atopy, and were more sensitive to methacholine than were controls, even if they had not shown recurrent wheezing episodes. It is suggested that an increased incidence of atopy, bronchial hyperresponsiveness, and reduced expiratory flows may be detectable in children with a history of acute bronchiolitis, regardless of the fact that they did not develop subsequent clinical symptoms suggestive of bronchial asthma.

Acute Disease↗
PubMed1999

Chronic alcoholism is associated with an imbalanced production of Th-1/Th-2 cytokines by peripheral blood T cells.

BACKGROUND: In the present study, we analyzed, at the intracellular level, the pattern of cytokine secretion by the major CD4+ and CD8strong+ peripheral blood (PB) T-cell subsets in patients with chronic alcoholism, and we correlated it both with the ethanol (EtOH) intake status and with the presence or not of alcoholic liver disease. METHODS: For that purpose, a total of 30 chronic alcoholic patients, 10 without liver disease (AWLD group) and 20 diagnosed with alcoholic liver cirrhosis (ALC) were studied. In all cases, flow cytometric measurement of intracellular expression of interferon-gamma (IFN-gamma), interleukin (IL)-2, and IL-4 was performed on PB CD4+ and CD8strong+ T lymphocytes. RESULTS: After studying AWLD patients, we found increased numbers of both CD4+ and CD8strong+ PB T cells with detectable cytoplasmic levels of the IL-2 and IFN-gamma T helper (Th)-1-associated cytokines, the greater increase being observed for this latter cytokine (p<0.001 for CD4+ and p<0.01 for CD8strong+ T cells). Regarding ALC patients, the pattern of expression of intracellular cytokines by PB T cells was different depending on the status of EtOH intake at the moment of entering this study. Accordingly, as in AWLD patients, ALC individuals who were actively drinking also displayed increased numbers of both CD4+ and CD8strong+ T cells expressing Th-1-associated cytokines. However, in these patients, expression of IFN-gamma, although being significantly greater than that observed in control individuals (p<0.05), was significantly lower than that in AWLD patients (p<0.01 and p<0.05, for CD4+ and CD8strong+ T cells, respectively). After a withdrawal period of > or =1 yr, ALC patients did not show significant changes in the cytoplasmic expression of Th-1-associated cytokines compared with the control group; in contrast, these patients showed a marked increase on the proportion of CD4+ and CD8strong+ T cells expressing IL-4, a Th-2-associated cytokine (p<0.01). After considering the ratio between the number of T cells expressing Th- (IFN-gamma)- and Th-2 (IL-4)-associated cytokines in each individual, we found that there was a significant imbalance in this ratio, with a predominance of IFN-gamma-producing T cells over IL-4+ T lymphocytes during EtOH intake. CONCLUSIONS: Our results showed that in patients with chronic alcoholism, active EtOH intake is associated with a Th-1 pattern of cytokine production by PB T cells.

Adult↗
PubMed1997

Syndrome of Alagille: radiological and sonographic findings. A review of 37 cases.

The objective of this study was to evaluate the association of intrahepatic cholestasis, pulmonary stenosis, and hyperlipemia with osseous and renal abnormalities in Alagille's syndrome. A total of 37 patients (25 males and 12 females) with ages ranging between 8 months and 27 years were included. Clinical records as well as radiological and ultrasonographic studies were reviewed. Chronic cholestasis was observed in all patients. Thirteen had favorable clinical outcome and normal hepatic sonograms. Clinical and sonographic evidence of portal hypertension was found in 13 patients and of cirrhosis in 8 patients. The remaining 3 patients required hepatic transplantation due to severe cholestasis. Hyperlipemia correlated with hepatic malfunction. Pulmonary stenosis and renal hypoplasia were the most frequently associated abnormalities. All patients showed a peculiar facies. Abnormal "butterfly" vertebrae were present in 18 patients and ulnar or phalangeal shortening in 11 patients. Ultrasonography allowed hepatobiliary disease assessment and helped to establish indications for hepatic transplantation. Renal and osseous abnormalities were not specific but in the appropriate clinical setting reinforced the diagnosis.

Adolescent↗
PubMed1996

US and color Doppler imaging of ocular and orbital disease in the pediatric age group.

Ultrasonography (US) is a rapid, accurate, noninvasive method of evaluating ocular and orbital disease. A wide spectrum of pediatric ocular and orbital disorders can be demonstrated with US: ocular congenital malformations, vitreoretinal disorders, primary and metastatic ocular and orbital neoplasms, inflammatory and congestive disease (focal or systemic), cystic disease, trauma, and foreign bodies. US may be the method of choice for studying ocular congenital anomalies and vitreoretinal disorders owing to its high definition and noninvasiveness. In ocular neoplasms, US demonstrates the morphology of the lesion, its solid or liquid nature, and the presence of calcifications. Its use is limited when the tumor extends outside the globe; computed tomography (CT) or magnetic resonance (MR) imaging must then be performed. In ocular trauma, US precisely demonstrates the presence of hemorrhage, retinal and choroidal detachment, and foreign bodies. CT and MR imaging are superior in evaluation of orbital disease. Color Doppler US often allows differential diagnosis of vascular, inflammatory, and neoplastic disease.

Child↗
PubMed1995

Shwachman-Diamond syndrome: clinical, radiological and sonographic aspects.

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease which is characterized by metaphyseal chondrodysplasia, neutropenia and pancreatic exocrine insufficiency. It presents with variable extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, and increased echogenicity of the pancreas without change in size. We discuss the differential diagnosis and review the literature.

Bone Marrow↗
PubMed1995

Shwachman-Diamond syndrome: clinical, radiological and sonographic findings.

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease, which is characterized by metaphyseal chondrodysplasia, neutropenia and exocrine pancreatic insufficiency. It presents with varying extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, as well as increased echogenicity of the normalized pancreas. We discuss the differential diagnosis and review the literature.

Bone Marrow Diseases↗
PubMed1995

Thyroid gland volume as measured by ultrasonography in preterm infants.

The volume of the thyroid gland was determined by ultrasonography in 30 preterm infants (27-36 weeks' gestation) born in Madrid. Thyroid gland volume significantly increased (p < 0.01) with postnatal and postmenstrual age and was very well correlated with body weight, height and surface area (p < 0.01). Serum thyroid hormones 3,5,3'-triiodothyronine (T3) and free thyroxine (FT4) were linearly correlated with postnatal and postmenstrual age, thus T3 and FT4 levels were also correlated with thyroid gland volume (p < 0.05). We report measurements of the thyroid gland volume obtained by ultrasonography in this group of preterm infants. Quantitative determination of thyroid gland volume is more accurate for the diagnosis of goitre than clinical criteria. It is also interesting to determine the thyroid gland volume in the neonatal period when the thyroid is particularly hypersensitive to the effects of iodine deficiency and excess.

Female↗