PubMed Health⌕ Search

Biomedical subjects

E Gallego

Publications and source records attributed to E Gallego.

At least 19 recordsLinked to original sources
PubMed2005

Artificial neural networks in neutron dosimetry.

An artificial neural network (ANN) has been designed to obtain neutron doses using only the count rates of a Bonner spheres spectrometer (BSS). Ambient, personal and effective neutron doses were included. One hundred and eighty-one neutron spectra were utilised to calculate the Bonner count rates and the neutron doses. The spectra were transformed from lethargy to energy distribution and were re-binned to 31 energy groups using the MCNP 4C code. Re-binned spectra, UTA4 response matrix and fluence-to-dose coefficients were used to calculate the count rates in the BSS and the doses. Count rates were used as input and the respective doses were used as output during neural network training. Training and testing were carried out in the MATLAB environment. The impact of uncertainties in BSS count rates upon the dose quantities calculated with the ANN was investigated by modifying by +/-5% the BSS count rates used in the training set. The use of ANNs in neutron dosimetry is an alternative procedure that overcomes the drawbacks associated with this ill-conditioned problem.

Algorithms↗
PubMed2005

Effects of cinnarizine, a calcium antagonist that produces human parkinsonism, in parkin knock out mice.

Cinnarizine, a calcium antagonist that produces parkinsonism in humans, induces behavioural changes such as alopecia, buco-lingual dyskinesia and reduction of motor activity in female parkin knock out (PK-KO) mice but not in wild-type (WT) controls. PK-KO mice have high striatal dopamine levels and increased dopamine metabolism in spite of low reduced tyrosine hydroxylase protein. Cinnarizine, which blocks dopamine receptors and increases dopamine release, further increased dopamine metabolism. PK-KO mice increased GSH levels as a compensatory mechanism against enhanced free radical production related to acceleration of dopamine turnover. Neuronal markers, such as beta-tubulin slightly increased in PK-KO and furthermore with cinnarizine. Astroglial markers were decreased in PK-KO mice, and this effect was potentiated by cinnarizine, suggesting abnormal glia in these animals. Microglia was hyperactivated in PK-KO midbrain, suggesting inflammation in these animals. Proapoptotic proteins were increased by cinnarizine and, to a lesser extent, in PK-KO mice. Our data indicate that mutation of parkin is a risk factor for drug-induced parkinsonism.

Analysis of Variance↗
PubMed2005

[Embolization of non-functioning renal allograft: efficacy and control of systemic inflammation].

BACKGROUND: The graft intolerance syndrome (fever, pain, haematuria) may lead to a chronic inflammatory disease, with cardiovascular repercussion. Nephrectomy is considered the classical treatment of these cases but nowadays renal vascular embolization has been suggested as a possible alternative treatment. The present study concerns seven cases trated with renal vascular embolization in our hospital summarizing data of graft intolerance syndrome and the chronic inflammatory disease. MATERIAL AND METHODS: Between january 2000 and december 2003 seven renal vascular embolization were performed in nonfunctioning renal allograft. The procedure was made with calibrated particles of 300-500micron. Data about complications related to the technique the same as analitic inflammatory parameters before and after treatment (CRP, ferritin, serum albumin, hemoglobin, erythropoietin) were registered. RESULTS: The patients were two men and five women, with median age of 39,7 +/- 8,8 years. The period beween the dialysis and the embolization was of 10,0 +/-8,2 months. Comparing the perion of admission in the hospital due to nephrectomy which was of 17,86+/-4,41 days, the period because of embolization was shorter, being 8,14 +/- 4,53 days. All analitic parameters studied, clearly improved after embolization with decrease of ferritin and CRP, increase of albumin and better hemoglobin level with lower erythropoietin dose. In five of the seven patients there was no renal captation with CT or gammagraphy. Four patients presented a postembolization syndrome, but no other important complication was registered. Neither reembolization nor renal nephrectomy was neccesary in any of the seven cases. CONCLUSION: Percutaneous renal embolization is a simple, easy, safety and effective technique that must be considered as an alternative treatment to nephrectomy, resolving the chronic inflammatory disease secondary to the graft intolerance syndrome.

Adult↗
PubMed2004

Characteristics of the neutron field of the facility at DIN-UPM.

A new source facility (241Am-Be) has been installed in a bunker-type room of large dimensions. To characterise the neutron fields in the facility, detailed calculations have been made with MCNP-4C, showing the different components of the neutron radiation reaching the reference points (direct, inscattered, backscattered). The contribution from neutrons scattered in the walls to the total ambient dose equivalent remains reasonably low (<10%) in the reference points. Additionally, spectra measurements have been performed with a Bonner spheres spectrometer with a 6LiI(Eu) scintillator (0.4 phi x 0.4 cm2), UTA4 response matrix and BUNKIUT unfolding code. The calculated and experimentally obtained spectra are compared, with small differences found in the epithermal and thermal region, attributable to the concrete composition used in the calculations. The H*(10) rate has been determined from the spectra, and then compared to the reading of an active dosemeter (LB6411), with differences found lower than 8%.

Algorithms↗
PubMed2004

[Primary amyloidosis associated to severe factor X deficiency].

Amyloidosis is a systemic disease characterized by generalized deposition of beta-organized proteic fibrillar material with green birefringence under polarized light, in different tissues and organs, the most frequent kidney, liver and heart, with important clinical repercussion. Primary or AL amyloidosis is the most common subtype of amyloidosis (1), confirmed by biopsy-proved amyloid deposition in abdominal fat pad, rectum, kidney or liver, if necessary, in which fragments of monoclonal light chains are deposited. Cases with factor X (Stuart factor) of coagulation deficiency associated are described, due to adsorption of this factor to amyloid fibrills. Normally, evolution is fatal, with only few months of survival. We report a case of primary amyloidosis with nephrotic syndrome, severe factor X deficiency (without bleeding complications), possible heart affection and short-term good response to chemotherapic treatment.

Amyloidosis↗
PubMed2003

[Influence of early or late referral to nephrologist over morbidity and mortality in hemodialysis].

OBJECTIVE: We studied the influence of early vs late referral to nephrologist of patients with chronic renal failure over clinical situation at the onset of hemodialysis and outcome. SUBJECTS AND METHODS: From january 1994 to december 1998, 139 patients started hemodialysis for end-stage renal disease at the Hospital General de Albacete, all of them included in the study and clinical follow-up concluded in december 2001. Patients with rapidly progressive glomerulonephritis were excluded. Early (ER) and late referral (LR) were defined by the time of first nephrology encounter greater than or less than 6 months respectively, before iniciation of hemodialysis. RESULTS: 106 patients (76.25%) were referred early; mean follow-up time 6.3 +/- 4.5 years. 33 patients (23.74%) had late referral, follow-up time was less then six months, 18 patients were followed during less than 4 weeks. There were no differences in demographic data and comorbid conditions between LR and ER patients (age, cardiac and vascular disease, diabetes, neoplasia...). Mean plasma concentration of creatinine and urea was significantly greater, whereas hematocrit and albumin were less in the LRA than the ER group. Emergency dialysis through central vein catheterisation was more frequent in the LR group. Number of admissions and duration of hospital stay were higher in the LR group. No significant differences in nutrition, dialysis doses or anemia were found between the two groups after 6 and 12 months of hemodialysis. Long term outcome was similar in both groups: no significant differences were found in percentage of patients transplanted or deceased after 3 years of treatment. Survival analysis failed to show a difference between ER and LR groups (mean survival time was 73.6 +/- 4.3 months and 73.0 +/- 6 months respectively). CONCLUSION: Late referral to the nephrologist is associated with increased early morbidity vs early referral, although long term outcome is not worse if predialysis comorbid conditions are comparable and dialysis care achieve equal results in dialysis doses, nutrition and anemia in both groups in the first months of treatment. Improvement of outcome of patients referred early to the nephrologist will depend on the adoption of preventive measures over comorbidity factors that should be applied in early stages of renal disease.

Female↗
PubMed2003

[Aphasias for verbal and sign languages are due to lesions of nearly localised but not identical brain regions of the left hemisphere].

OBJECTIVES: To study the characteristics of verbal and sign language aphasia in a patient fluent in both languages, who had had a recent left hemisphere stroke as well as to localise the site responsible for Spanish sign language aphasia. PATIENT AND METHODS: 56 years old male, with risk factors for stroke, who presented an episode of sudden onset aphasia and right hemiplegia that partially recovered in a few hours. The residual deficit of language was explored with a detailed protocol that included comprehension, denomination, oral and phonetic praxis, propositional and automatic spontaneous language, reading and writing tasks. The examination of verbal and sign language was video-recorded. The lesion was localised by magnetic resonance imaging 24 days after the stroke. RESULTS: The patient, whose infarction involved the superior temporal gyrus and sylvian operculum, presented similar abnormalities for comprehension of complex sentences, many phonemic paraphasias and no trouble to repeat single words. Oral language was not fluent, but sign language was quite fluent with a rich vocabulary, but with semantic paraphasias, agrammatism and without self-criticism for his own mistakes. CONCLUSIONS: The pattern of oral and sign language alterations is partially different, more for expressive than perceptive discourse, although both types of aphasias are caused by lesions of the left hemisphere. The regions responsible for these abnormalities of both symbolic languages are localised close to each other, but not in the same place.

Aphasia, Broca↗
PubMed2002

Response components of LiF:Mg,Ti around a moderated Am-Be neutron source.

The responses of TLD-1010, TLD-700 and TLD-600 thermoluminescence dosemeters to the radiation field inside a water tank enclosing an isotopic 241Am-Be neutron source are analysed. Separate contributions coming from thermal neutrons, neutrons with energies above thermal and gamma rays to the total response of the three types of TLD are obtained. This is accomplished by assuming that the gamma responses for materials with different 6Li enrichments are identical and that the neutron response of TLD-700 is negligible compared to TLD-100 and TLD-600. The last assumption is tested by Monte Carlo simulations of the neutron energy spectrum at the points where the TLDs are irradiated.

Americium↗
PubMed2001

[Low sensitivity of IGF-I, IGFBP-3 and urinary GH in the diagnosis of growth hormone insufficiency in slowly-growing short-statured boys. Grupo Español de Estudio de la Talla Baja].

BACKGROUND: The usefulness of IGF-I, IGFBP-3, and the urinary GH excretion in the diagnostic evaluation of growth retardation in boys with short stature was studied. SUBJECTS AND METHOD: Serum samples from two GH-stimulation tests and two 24-h urine samples were sent to a Central Laboratory to measure serum and urinary GH, serum IGF-I, IGFBP-3 and GHBP, both in absolute and standardized values (Z-score). Short children were classified as growth hormone deficient (GHD) (n = 25), and idiopathic short statured (ISS) (n = 54), on the basis of the peak stimulated GH concentration of < 7.5 microg/l or > or = 7.5 microg/l respectively. A group of 15 normally growing children and adolescents was also included. RESULTS: Height-velocity standard deviation score (HV)-SDS was lower and body mass index higher in GHD than ISS. Standardized IGF-I differed significantly by ANOVA among the three groups (p = 0.001). Multiple stepwise linear regression analysis with HV-SDS as dependent variable showed IGF-I SDS as the best predictor followed by peak GH clonidine response and uGH excretion. ROC curves showed optimum cut-off level for IGF-I SDS as 2.05 (sensitivity: 32%, specificity: 90%) and 1.14 for IGFBP-3 SDS sensitivity: 28%, specificity: 94%). CONCLUSIONS: Standardized IGF-I and IGFBP-3 measurements were highly efficient only in diagnosis of severe GHD, but they show low sensitivity for the diagnosis of isolated idiopathic GHD as defined according to the low GH response to stimulation tests.

Adolescent↗
PubMed2000

The self-organization of adenosine 5'-triphosphate and adenosine 5'-diphosphate in aqueous solution as determined from ultraviolet hypochromic effects.

The self-association of adenosine 5'-triphosphate (ATP) and of adenosine 5'-diphosphate (ADP) was studied in aqueous solution at different pH values, over the concentration range from 5 x 10(-6) to 5 x 10(-2) M, by ultraviolet spectroscopy. Measures of the molar absorptivity of the ultraviolet bands of these compounds with increasing concentration have shown two hypochromic effects, at concentrations below 10(-3) and above 10(-3) M, respectively. These results can be interpreted in terms of self-association processes involving the formation of dimers and of polymers. From the fitting of the experimental curves of hypochromic effects, self-association constants for dimerization and polymerization were calculated. The results obtained are discussed in relation to the values reported in the literature and indicate the influence of the concentration range not only on the numerical value but also on the order of magnitude of the association constants. Comparison of ATP with ADP shows that the length of the phosphate chain may be a relevant feature in the nature of the self-organization processes in these adenine nucleotides in aqueous solution.

Adenosine Diphosphate↗
PubMed2000

Self-association of pyridine-2,6-dicarboxylic acid in aqueous solution as determined from ultraviolet hypochromic and hyperchromic effects.

The self-association of pyridine-2,6-dicarboxylic acid (dipicolinic acid), was studied in aqueous solution at the pH values of 0.2, 3.5, 6.9 and 13.0, by ultraviolet spectroscopy. The variation in molar absorptivity with the concentration of this compound was measured for the band in the mid-ultraviolet region. Deviations from Beer-Lambert law with increasing concentration were found at the pH values of 0.2, 3.5 and 6.9. Hypochromic effects were detected at pH 0.2 and 6.9, while a hyperchromic effect was observed at pH 3.5. These results were interpreted in terms of self-association leading to the formation of dimers. From the fitting of the experimental curves of hypochromic or hyperchromic effects, self-association constants were calculated. The occurrence of hypochromic and hyperchromic effects was analyzed in terms of vertical and horizontal interactions, respectively, to elucidate the nature of the self-association processes, stacking or hydrogen bonding, relevant to each of the protolytic species of dipicolinic acid in aqueous solution.

Dimerization↗
PubMed2000

A study by ultraviolet spectroscopy on self-association of purine, 6-methylpurine, benzimidazole, and imidazo [1,2-a]pyridine in aqueous solution.

The self-association of four heteroaromatic compounds with fused five- and six-membered rings: purine, 6-methylpurine, benzimidazole, and imidazo[1,2-a]pyridine, was studied in aqueous solution at different pH values, by ultraviolet spectroscopy. The variation in molar absorptivity with the concentration of these compounds was measured for the band systems in the mid-ultraviolet region. Hypochromic deviations from the Beer-Lambert law with increasing concentration were found for all compounds. These results were interpreted in terms of self-association processes involving the formation of dimers and, in certain cases, also the formation of polymers. From the fitting of the experimental curves of hypochromic effects, self-association constants for dimerization and polymerization were calculated. The results obtained are discussed in relation to the self-association properties of the building blocks of each compound, studied by us in previous works. The relevance of the position of the nitrogen atoms at the five- and six-membered rings was analyzed to elucidate the nature of the self-association processes, in particular the tendency to polymerization. The values of the calculated self-association constants are discussed in relation to the intermolecular interaction energies of these compounds in aqueous solution.

Benzimidazoles↗
PubMed2000

Amino acid losses during hemodialysis with polyacrylonitrile membranes: effect of intradialytic amino acid supplementation on plasma amino acid concentrations and nutritional variables in nondiabetic patients.

BACKGROUND: Malnutrition is highly prevalent in hemodialysis patients. Amino acid (AA) losses during the dialysis procedure may be a contributing factor. OBJECTIVES: The objectives of this study were 1) to prospectively evaluate AA losses and their effect on plasma AA concentrations during dialysis with polyacrylonitrile at baseline and after administration of AAs by intradialysis and 2) to investigate the effects of intradialytic AA supplementation on nutritional status. DESIGN: Seventeen stable patients without diabetes who were receiving hemodialysis were studied. In the first phase, AA losses were evaluated over 2 wk in 10 patients randomly assigned to receive AA supplementation. AA losses were analyzed during the first week without supplementation and during the second week with AA administration. In the second phase, the patients' nutritional status was investigated after 3 mo of AA supplementation and was compared with those in 7 patients not receiving AAs. RESULTS: Mean +/- SD) AA losses during a 4-h dialysis session were 12 +/- 2 g; there was a significant decrease in plasma AA concentrations (386 +/- 298 micromol/L for essential and 902 +/- 735 micromol/L for nonessential AAs). After administration of AAs, the losses increased to 28 +/- 4 g. However, this procedure produced a positive net balance of AAs (10.6 +/- 5.6 g for total AAs), preventing a reduction in plasma concentrations. After 3 mo of AA administration, there was a significant increase in protein catabolic rate and serum albumin and transferrin. This improvement occurred without any change in the dialysis dose, ruling out the possibility that an increase in dialysis efficiency played a role. CONCLUSIONS: Intradialysis adequately provides AA supplements, prevents reductions in plasma AA concentrations, and favorably affects the nutritional status of patients receiving hemodialysis.

Acrylic Resins↗
PubMed1999

Urinary protein excretion and serum tumor necrosis factor in diabetic patients with advanced renal failure: effects of pentoxifylline administration.

In 24 diabetic patients with advanced renal failure (creatinine clearance [C(Cr)] < 35 mL/min), we prospectively studied serum tumor necrosis factor-alpha (TNF-alpha) levels, the possible relationship with urinary protein excretion, and the effects of pentoxifylline (PTF) administration. PTF (400 mg daily) was administered for 6 months to 14 patients, and the results were compared with data from a control group (n = 10). Baseline parameters were similar in both groups. At the end of the study, urinary protein excretion and serum TNF-alpha decreased in the active group from 2.7 (1.2 to 5.8) g/d and 569 +/- 285 pg/mL to 1.1 (0.3 to 4.0) g/d and 329 +/- 232 pg/mL, respectively (P < 0.001). By contrast, proteinuria and TNF-alpha did not change in the control group. Regression analysis showed a significant correlation between proteinuria and serum TNF-alpha both at basal (r = 0.55) and at the sixth month (r = 0.57). Furthermore, the reduction of urinary protein excretion was strongly correlated with the decrease of TNF-alpha (r = 0.72, P < 0.01). Serum Cr and C(Cr) remained stable in both groups during the study. Our findings suggest that cytokines might play a role in renal damage in diabetic nephropathy. PTF is effective in reducing proteinuria in diabetic patients with advanced renal failure. The anticytokine activity of PTF may be a further explanation for this antiproteinuric effect.

Aged↗
PubMed1999

Effects of pentoxifylline on the haematologic status in anaemic patients with advanced renal failure.

OBJECTIVE: Erythropoietin (EPO) deficiency is the main cause of renal anaemia. However, inhibition of erythropoiesis by cytokines such as tumour necrosis factor alpha (TNF-a) may play an important role. The aim of this work was to study the effects of pentoxifylline, an agent with anti-TNF-a properties, on the haematologic status in anaemic patients with advanced renal failure. MATERIAL AND METHODS: In a prospective study, 7 anaemic patients with advanced renal disease (creatinine clearance <30 ml/min) were treated with pentoxifylline (400 mg orally daily) for 6 months. The evolution of haemoglobin, haematocrit, creatinine clearance and serum EPO and TNF-a a concentrations were compared with those obtained from an untreated control group. RESULTS: Haemoglobin and haematocrit significantly increased in the pentoxifylline-treated patients (9.9+/-0.5 g/dl and 27.9+/-1.6% at baseline; 10.6+/-0.6 g/dl and 31.3+/-1.9% at the 6th month, respectively, p < 0.01), whereas no variation was seen in the control group. Serum EPO levels remained stable in all patients. However, the serum TNF-a concentration decreased significantly in patients receiving pentoxifylline (basal 623+/-366 pg/ml; 6th month 562+/-358 pg/ml, p < 0.01), but not in the control group. CONCLUSIONS: Our findings suggest that the inhibition of erythropoiesis by cytokines may play a significant role in renal anaemia. The administration of agents with anti-cytokine properties, such as pentoxifylline, can improve the haematologic status in anaemic patients with advanced renal failure.

Aged↗
PubMed1999

Autosomal dominant polycystic kidney disease associated with familial sensorineural deafness.

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by both renal and non-renal disorders. Extrarenal involvement includes noncystic manifestations such as cardiovascular abnormalities, colonic diverticula and intracranial aneurysms. Familial sensorineural hearing loss (SNHL) has been included in the definition of Alport's syndrome. However, other types of nephropathy have been occasionally associated with hereditary deafness. The association of ADPKD with hereditary SNHL has not been previously documented. We report a family with ADPKD associated with bilateral sensorineural deafness in a pedigree of four affected members in four generations.

Deafness↗