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S Díez

Publications and source records attributed to S Díez.

17 recordsLinked to original sources
PubMed2006

CASANDRA: a prototype implementation of a system of network progressive transmission of medical digital images.

In this paper, a prototype for progressive transmission of medical digital 2D images through the network, called CASANDRA, is presented. The prototype consists of the server part and the client part. In the server part, the images are acquired, stored, computed their wavelet transform and the wavelet coefficients stored, then transmitted progressively, when required, via TCP to the client. In the client part, with the inverse wavelet transform, the received wavelet coefficients are used to build successive improved reconstructions of the image. This prototype has been implemented and is being tested in the Radiotherapy Service of the Valencia University Hospital (Valencia, Spain).

Medical Informatics Applications↗
PubMed2005

MCNP simulation of a Theratron 780 radiotherapy unit.

A Theratron 780 (MDS Nordion) 60Co radiotherapy unit has been simulated with the Monte Carlo code MCNP. The unit has been realistically modelled: the cylindrical source capsule and its housing, the rectangular collimator system, both the primary and secondary jaws and the air gaps between the components. Different collimator openings, ranging from 5 x 5 cm2 to 20 x 20 cm2 (narrow and broad beams) at a source-surface distance equal to 80 cm have been used during the study. In the present work, we have calculated spectra as a function of field size. A study of the variation of the electron contamination of the 60Co beam has also been performed.

Algorithms↗
PubMed2004

Electric-field-induced B1-B2 transition in bent-core mesogens.

We report experimental results on two bent-shaped mesogens showing the B1 phase. Contrary to the conventional B1 structures, we have found that our compounds display a clear electro-optic effect in this phase. Under the influence of a 100-Hz square-wave electric field of moderate amplitude, an increase of the birefringence is observed. However, no switching current is detected, indicating that the materials remain antiferroelectric. For high enough fields, a drastic change in the texture occurs. This change is a phase transition to a B2 phase, and shows the typical antiferroelectric switching of this phase. The induced B2 phase has been identified to be homochiral. Upon removal of the field, the B1 structure is recovered. Our study is based on differential scanning calorimetry, x-ray, electro-optics, polarization reversal, and dielectric measurements.

Journal Article↗
PubMed2003

[Diagnosis of septo-pyramidal defects. Our report].

OBJECTIVE: The aim of the study is to determine the characteristics of patients who are operated on because of a nasal or septal deformity: clinical features before surgery, physical examination, anterior active rhinomanometry, and computed tomography (CT). METHODS: We retrospectively reviewed prospective data collected on 372 patients operated on between January 1998 and June 2002 by means of a septoplasty or a rhinoplasty. RESULTS: Gender distribution was: 253 male, 119 female. A smaller percentage of men underwent correction of pyramidal deformities in comparison to women. Nasal endoscopic examination diagnosed associated inflammatory pathologies in 12.4% of patients. We found a significant relationship between previous nasal trauma, laterorrinia and defects of the dorsum. Anterior active rhinomanometry had a high variability between patients. CONCLUSIONS: Prospective data collected on these patients was useful to know more precisely our activities and how to adapt them to suit management decisions. Endoscopic examination proved high efficiency in the diagnosis of this pathology.

Adolescent↗
PubMed2002

[Prevalence of tobacco and alcohol use following treatment in patients with head and neck squamous carcinoma: a cross-sectional study].

OBJECTIVE: To evaluate the prevalence of tobacco and alcohol use following treatment in patients with head and neck squamous cell carcinoma, and to determine factors possibly related to this use MATERIAL AND METHODS: A transversal study on tobacco and alcohol use following treatment for head and neck squamous cell carcinoma was performed in patients on ambulatory visits to our center. RESULTS: From 582 patients evaluated, 13% regularly smoked post-treatment, and 21% consumed alcohol. The related variables for tobacco use post-treatment were the kind of treatment received and previous tobacco use. The related variables for alcohol use post-treatment were age, sex and previous use of tobacco and alcohol. CONCLUSIONS: Despite warnings, 13% of patients with previous head and neck squamous cell carcinoma continued smoking and 21% persisted in alcohol use.

Adult↗
PubMed2002

Organotin contamination in sediments from the Western Mediterranean enclosures following 10 years of TBT regulation.

Organotin (OT) compounds, namely butyl and phenyl, were measured in 38 recent sediments collected in harbours of the Western Mediterranean Sea (Northern: 4 and Southern: 9) and domestic and industrial sewage disposal sites (Northern: 9 and Southern: 1). Butyltins were the predominant tin species identified as being tributyltin (TBT) widespread in the whole area which suggests recent inputs of OTs. The highest levels of TBT were detected in commercial harbours associated with inputs from large vessels (average value: 5.0 microg TBT g(-1). Moreover, relatively high TBT values were also detected in fishing and recreational boating areas (average level ca. 1.0 microg TBTg(-1)). Phenyltin derivatives occurred at lower levels than butyltins being the monophenyltin the predominant compound (average values 45-945 ng g(-1)). The large predominance of the phenyltin degradation products (i.e. mono and diphenyltin) over the parent compound (i.e. triphenyltin) suggests that there are almost no recent inputs of these compounds. Furthermore, a comparative study of the OT occurrence in the sewage sludge disposal sites offshore Barcelona and Almeria (domestic) and into the Tarragona harbour (industrial) shows that domestic primary sewage sludge effluents can contribute to coastal OT pollution (244ng TBT g(-1)). Nevertheless, sewage sludge is a secondary source of OT contamination in the coastal environment in comparison to commercial harbours. In a comparative study with previous data collected in the late 1980s, the present study reveals that OT regulations established in the Mediterranean region in 1991 on the use of TBT-based antifouling paints have been effective in marinas, but reveals a significant TBT contamination in commercial and fishing harbours.

Environment↗
PubMed2001

Detection of melanin-like pigments in the dimorphic fungal pathogen Paracoccidioides brasiliensis in vitro and during infection.

Melanins are implicated in the pathogenesis of several human diseases, including some microbial infections. In this study, we analyzed whether the conidia and the yeasts of the thermally dimorphic fungal pathogen Paracoccidioides brasiliensis produce melanin or melanin-like compounds in vitro and during infection. Growth of P. brasiliensis mycelia on water agar alone produced pigmented conidia, and growth of yeasts in minimal medium with L-3,4-dihydroxyphenylalanine (L-DOPA) produced pigmented cells. Digestion of the pigmented conidia and yeasts with proteolytic enzymes, denaturant, and hot concentrated acid yielded dark particles that were the same size and shape as their propagules. Immunofluorescence analysis demonstrated reactivity of a melanin-binding monoclonal antibody (MAb) with the pigmented conidia, yeasts, and particles. Electron spin resonance spectroscopy identified the yeast-derived particles produced in vitro when P. brasiliensis was grown in L-DOPA medium as a melanin-like compound. Nonreducing polyacrylamide gel electrophoresis of cytoplasmic yeast extract revealed a protein that catalyzed melanin synthesis from L-DOPA. The melanin binding MAb reacted with yeast cells in tissue from mice infected with P. brasiliensis. Finally digestion of infected tissue liberated particles reactive to the melanin binding MAb that had the typical morphology of P. brasiliensis yeasts. These data strongly suggest that P. brasiliensis propagules, both conidia and yeast cells, can produce melanin or melanin-like compounds in vitro and in vivo. Based on what is known about the function of melanin in the virulence of other fungi, this pigment may play a role in the pathogenesis of paracoccidioidomycosis.

Animals↗
PubMed1999

Apparent cure of Graves-Basedow disease after sibling allogeneic bone marrow transplantation.

Evidence that allogeneic bone marrow transplantation (BMT) can cure or alter the course of intractable autoimmune diseases comes from both extensive experimental work in animal models and anecdotal case reports in humans. We describe a female patient diagnosed as having severe aplastic anaemia (SAA), hyperthyroidism and ophthalmopathy of Graves-Basedow disease who received a BMT from her histocompatible sister. Fifty-three months after BMT, complete remission of hyperthyroidism and ocular signs persists. The SAA is cured and she is free of any chronic graft-versus-host disease (GVHD). In the early post-BMT period, PCR analysis of bone marrow and peripheral blood cells confirmed a complete chimerism of donor origin. Thus, it is plausible to attribute the resolution of the patient's thyroid hyperfunction and opththalmopathy to the replacement of the host immune system.

Adult↗
PubMed1999

[Antibiotic treatment in surgery for cholesteatoma].

Cholesteatoma surgery is considered as a dirty one and consequently tributary of preoperative and postoperative antibiotic treatment. Thirty-seven patients diagnosed of cholesteatoma and surgically treated in 1994 are retrospectively analyzed in this article. All of them, whether or not presented with active preoperative otorrhea, received a protocolized antibiotic treatment with topical gentamicin and dexamethasone and oral clindamycin during seven postoperative days. The presence or absence of preoperative or postoperative infection, usually as suppuration is analyzed. Otopyorrhea occurred in 22 patients (62%) before surgery and only in 9 cases (25%) after surgery. Preoperative discharging ears showed greater disposition to continuing the suppuration. The surgical technique followed and the reconstructive middle ear procedure--with autologous bone or other synthetic materials (PORP, TORP)--have not proved, statistically, any predictably value regarding the appearance of any active postoperative infection. As a result of the study done, oral ciprofloxacin has been protocolized only in those adults showing a refractory suppuration to the antibiotic treatment employed. In patients with preoperative otorrhea, topical ciprofloxacin has been protocolized before surgery with the main aim to decrease the postoperative infections incidence of these cases.

Adolescent↗
PubMed1998

Use of the 27-kilodalton recombinant protein from Paracoccidioides brasiliensis in serodiagnosis of paracoccidioidomycosis.

Paracoccidioidomycosis (PCM) is one of the most important endemic mycoses in Latin America; it is usually diagnosed by observation and/or isolation of the etiologic agent, Paracoccidioides brasiliensis, as well as by a variety of immunological methods. Although the latter are effective, two circumstances, cross-reactions with other mycotic agents and antigen preparation that is marked by extreme variability among lots, hinder proper standardization of the procedures. To circumvent this lack of reproducibility, molecular biology tools were used to produce a recombinant 27-kDa-molecular-mass antigen from this fungus; a sizable quantity of this antigen was obtained through fermentation of Escherichia coli DH5alpha, which is capable of expressing the fungal protein. The latter was purified by the Prep-Cell System (Bio-Rad); the recovery rate of the pure protein was approximately 6%. A battery of 160 human serum samples, consisting of 64 specimens taken at the time of diagnosis from patients with PCM representing the various clinical forms plus 15 serum specimens each from patients with histoplasmosis and aspergillosis, 10 each from patients with cryptococcosis and tuberculosis, 6 from patients with coccidioidomycosis, and 40 from healthy subjects, were all tested by an indirect enzyme-linked immunosorbent assay with the purified 27-kDa recombinant protein. The latter was used at a concentration of 1.0 microgram/well; there were three serum dilutions (1:1,000, 1:2,000, and 1:4,000). The experiment was repeated at least twice. The average sensitivity for both experiments was 73.4%; in comparison with the healthy subjects, the specificity for PCM patients was 87.5% while for patients with other mycoses, it was 58.7%. Important cross-reactions with sera from patients with aspergillosis and histoplasmosis were detected. The positive predictive value of the test was 90.4%. These results indicate that it is possible to employ recombinant antigenic proteins for the immunologic diagnosis of PCM and, by so doing, achieve high coverage rates. Furthermore, antigen reproducibility can now be ensured, thus facilitating inter- and intralaboratory standardization.

Antibodies, Fungal↗
PubMed1997

The long-term outcome of pituitary irradiation after unsuccessful transsphenoidal surgery in Cushing's disease.

BACKGROUND: Irradiation of the pituitary is widely considered the most appropriate treatment for patients with Cushing's disease in whom transsphenoidal microsurgery has been unsuccessful. However, there is little information about the long-term efficacy of this treatment. METHODS: We used external pituitary radiation to treat 30 adult patients with persistent or recurrent Cushing's disease after unsuccessful transsphenoidal surgery. The mean (+/-SD) dose of radiation was 50+/-1 Gy. Pituitary and adrenal function was assessed every six months after radiation therapy. Remission was defined as the regression of symptoms and signs of Cushing's syndrome, normal urinary cortisol excretion, and a low plasma cortisol concentration in the morning after the administration of 1 mg of dexamethasone at midnight. RESULTS: Twenty-five patients (83 percent) had remissions during a median follow-up of 42 months (range, 18 to 114). The remissions began 6 to 60 months after radiation therapy, but in most cases (22 patients) remission occurred during the first 2 years. None of the 25 patients had a relapse of Cushing's disease after remission was achieved. There was no relation between the response to radiotherapy and sex, age, urinary cortisol excretion before radiotherapy, the interval between surgery and radiotherapy, whether a pituitary adenoma was found by pathological examination, or tumor size. Seventeen patients had a deficiency of growth hormone after radiation therapy, 10 had a deficiency of gonadotropins, 4 had a deficiency of thyrotropin, and 1 had a deficiency of corticotropin. CONCLUSIONS: Pituitary irradiation is an effective and well-tolerated treatment for patients with Cushing's disease in whom transsphenoidal surgery is unsuccessful.

Adolescent↗
PubMed1997

Laryngeal carcinoma in patients without a history of tobacco and alcohol use.

BACKGROUND: The medical literature on laryngeal carcinomas in patients without a history of tobacco and alcohol use is sparse. METHODS: A retrospective review of 933 laryngeal carcinomas treated in our center between January 1984 and December 1993 was made. Characteristics and results of patients with history of tobacco and alcohol use were compared with those who used neither. RESULTS: Of all patients with laryngeal carcinomas, 31 (3.3%) had no history of tobacco and alcohol use. In this group of patients, distribution between sexes was similar, and the mean age of patients was 70 years, compared with 63 years in the group with a history of tobacco and alcohol use. The survival rate was better in the former group. CONCLUSIONS: Patients without a history of tobacco and alcohol use who developed laryngeal cancer showed different characteristics compared with smokers or drinkers; they were an average of 10 years older, they showed no male predominance, and their lesions were mainly located in the glottis, which permitted early diagnosis and a higher survival rate.

Adult↗
PubMed1994

Dexamethasone-suppressible feminizing adrenal adenoma.

A 39 year old man presented with gynaecomastia, loss of libido and high blood pressure. Hormone studies revealed elevated plasma levels of oestradiol and its precursors, which increased in response to adrenocorticotrophic hormone and were reduced to normal levels with dexamethasone. Computed tomography disclosed a left adrenal mass and surgery was performed. The removed tumour weighed 84 g and the histological diagnosis was of adenoma. Nine years after surgery, he is asymptomatic, without hypertension, and radiological and or hormonal evidence of recurrence. We discuss the hormone profile in this case and the dynamics of steroid production by the tumour which, in contrast to the classical concept of tumour autonomy, showed dependence of oestradiol secretion on endogenous adrenocorticotrophic hormone.

Adenoma↗
PubMed1989

[Thyrotropin-producing adenoma of the hypophysis].

A patient with a thyrotropin (TSH) secreting pituitary adenoma had hyperthyroidism with high levels of thyroid hormones and inadequate TSH secretion. After the challenge with thyrotropin releasing hormone (TRH), TSH level did not change. The normalization of plasma levels of thyroid hormones with antithyroid drugs was followed by an important increase in TSH levels. The adenoma was resected by the transphenoidal route and the diagnosis was confirmed by immunohistochemical study. Inadequate TSH secretion persisted after surgery, and radiation therapy with lineal accelerator was attempted. At present, one year after radiation therapy, inadequate TSH secretion requiring antithyroid drugs persists. We describe this clinical picture and briefly discuss the literature.

Adenoma↗
PubMedDate not supplied

PCR with Paracoccidioides brasiliensis specific primers: potential use in ecological studies.

The precise microenvironment of Paracoccidioides brasiliensis has not yet been discovered perhaps because the methods used are not sensitive enough. We applied to this purpose the polymerase chain reaction (PCR) using three sets of specific primers corresponding to two P. brasiliensis genes. This fungus as well as several other fungi, were grown and their DNA obtained by mechanical disruption and a phenol chloroform isoamylalcohol-based purification method. The DNA served for a PCR reaction that employed specific primers from two P. brasiliensis genes that codify for antigenic proteins, namely, the 27 kDa and the 43 kDa. The lowest detection range for the 27 kDa gene was 3 pg. The amplification for both genes was positive only with DNA from P. brasiliensis; additionally, the mRNA for the 27 kDa gene was present only in P. brasiliensis, as indicated by the Northern analysis. The standardization of PCR technology permitted the amplification of P. brasiliensis DNA in artificially contaminated soils and in tissues of armadillos naturally infected with the fungus. These results indicate that PCR technology could play an important role in the search for P. brasiliensis' habitat and could also be used in other ecological studies.

Animals↗