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Biomedical subjects

C Ceballos

Publications and source records attributed to C Ceballos.

15 recordsLinked to original sources
PubMed2005

Contrast cancellation technique applied to digital x-ray imaging using silicon strip detectors.

Dual-energy mammographic imaging experimental tests have been performed using a compact dichromatic imaging system based on a conventional x-ray tube, a mosaic crystal, and a 384-strip silicon detector equipped with full-custom electronics with single photon counting capability. For simulating mammal tissue, a three-component phantom, made of Plexiglass, polyethylene, and water, has been used. Images have been collected with three different pairs of x-ray energies: 16-32 keV, 18-36 keV, and 20-40 keV. A Monte Carlo simulation of the experiment has also been carried out using the MCNP-4C transport code. The Alvarez-Macovski algorithm has been applied both to experimental and simulated data to remove the contrast between two of the phantom materials so as to enhance the visibility of the third one.

Algorithms↗
PubMed2001

Venous endothelial function in postmenopausal women after six months of tibolone therapy.

STUDY OBJECTIVE: To test venous endothelial function in long-term climateric therapy with tibolone. DESIGN: Measurement of dorsal hand-vein diameter by venous occlusion plethysmography during infusion of norepinephrine (NE), bradykinin (BK), NG-monomethyl L-arginine (L-NMMA) and sodium nitroprusside (SNP). SETTING: Plethysmography and Menopause Units. University Hospital Valdecilla. Santander. Spain. PATIENTS: Eleven postmenopausal women having continuous treatment with oral tibolone (2.5 mg/day) for 6 months. INTERVENTIONS: Three plethysmography studies were made: at baseline, and at three and six months of treatment. MAIN OUTCOME MEASURES: Dorsal hand-vein diameter measured by venous occlusion plethysmography during infusion of NE, BK, L-NMMA and SNP. RESULTS: (a) Baseline study: maximum dilation with BK was 54.2+/-10.2%. (b) Three-month study: BK dilation of 71.5+/-11.9%, with a significant increase of 17.3% (P=0.019) compared with baseline. (c) Six-month study: BK dilation of 77.5+/-11.9%, with a significant increase 23.3% (P=0.002) compared with baseline. Maximal vasodilation was reached with SNP in the three studies and L-NMMA infusion has a similar vasoconstrictor response in the three studies. CONCLUSIONS: Long-term climateric therapy with tibolone improves vein endothelium-dependent vasodilation suggesting a positive impact of this drug on endothelial function.

Administration, Oral↗
PubMed2001

SPECT scan in somatization disorder patients: an exploratory study of eleven cases.

OBJECTIVE: There are no previous studies using single photon emission computed tomography (SPECT) scans in somatization disorder (SD) patients. The aim of this paper is to assess SPECT imaging abnormalities in SD patients and study any relation to laterality. METHOD: Eleven SD patients from the Somatization Disorder Unit of Miguel Servet University Hospital, Zaragoza, Spain, not fulfilling criteria for any other psychiatric disorder and showing normal computed tomography (CT) and magnetic resonance imaging (MRI) images were studied with SPECT. Patients with DSM-IV axis I comorbidity were ruled out because it has been demonstrated that SPECT scans can show abnormalities in patients with depression and anxiety disorders. The technique used for SPECT was 99mTc-D,1,hexamethylpropyleneamide-oxime (99mTc-HMPAO) in four patients and 99mTc-bicisate in the other seven. The SPECT scans were evaluated without knowledge of clinical data and entirely by visual inspection. RESULTS: Seven out of 11 (63.6%) SD patients showed hypoperfusion in SPECT imaging. In four cases there was hypoperfusion in the non-dominant hemisphere and the predominance of pain symptoms took place in the contralateral hemibody. In the other three patients hypoperfusion was bilateral. The anatomical regions affected were cerebellum (four cases), frontal and prefrontal areas (three cases), temporoparietal areas (two cases) and the complete hemisphere (one case). CONCLUSIONS: A proportion of SD patients may present hypoperfusion in SPECT images, uni- or bilaterally, in different brain areas. Possible aetiological explanations for this finding are discussed. Controlled studies are necessary to confirm or refute this hypothesis.

Adult↗
PubMed2000

Venous endothelial function in postmenopausal women who are receiving long-term estrogen and progestagen therapy.

OBJECTIVE: To test venous endothelial function during long-term hormone replacement therapy (HRT) and after treatment withdrawal. DESIGN: Measurement of dorsal hand-vein diameter by venous occlusion plethysmography during infusion of norepinephrine, bradykinin, NG-monomethyl L-arginine, and sodium nitroprusside. SETTING: Plethysmography and menopause units, University Hospital Marqués de Valdecilla, Santander, Spain. PATIENT(S): Twenty postmenopausal women, of whom 10 were assigned to receive no hormone replacement therapy (HRT) for 6 months after plethysmography (group A) and 10 were assigned to receive HRT for 6 months (group B). After 6 months, HRT was administered to group A and withdrawn from group B for another 6 months. INTERVENTION(S): Plethysmography at baseline and at 6 and 12 months. MAIN OUTCOME MEASURE(S): Dorsal hand-vein diameter measured by venous occlusion plethysmography during infusion of norepinephrine, bradykinin, NG-monomethyl L-arginine, or sodium nitroprusside. RESULT(S): At 6 months, the maximum dilation obtained with bradykinin was 48.8 +/- 7.58% in group A and 76.7 +/- 12.9% in group B. At 12 months, maximum bradykinin dilation increased to 74.3 +/- 14.2% in group A and decreased to 54.0 +/- 15.9% in group B. CONCLUSION(S): Long-term HRT with estrogen plus progestin improves endothelium-dependent vasodilation, but this effect is lost in a relatively short time. Endothelial function in dorsal hand veins is an easy-to-use plethysmography model that can be used in serial studies.

Bradykinin↗
PubMed2000

[Why evidence-based medicine? 20 years of meta-analysis].

BACKGROUND: Meta-analysis, described within evidence-based medicine, has become a frequent issue in recent medical literature. An exhaustive search of reported meta-analysis from any medical specialty is described. MATERIAL AND METHODS: Search of papers included in Medline or Embase between 1973-1998. A study of intra and inter-reviewers liability about selection and classification have been performed. A descriptive analysis of the reported papers (frequency tables and graphics) is described, including differences of mean of reported meta-analysis papers by medical specialty and year. RESULTS: 1,518 papers were selected and classified. Most frequently found (45.91%) were: methodology (15.7%), psychiatry (11.79%), cardiology (10.01%) and oncology (8.36%). Inter personal agreement was 0.93 in selecting papers and 0.72 in classifying them. Between 1977-1987 overall mean of reported studies of meta-analysis (1.67 + 4.10) was significatively inferior to the 1988-1998 (49.54 + 56.55) (p < 0.001). Global number of meta-analysis was positively correlated (p < 0.05) with the number of studies about fundamentals and methodology during the study period. CONCLUSIONS: The method used to identify meta-analysis reports can be considered to be adequate; however, the agreement in classifying them in medical specialties was inferior. A progressive increase in the number of reported meta-analysis since 1977 can be demonstrated. Specialties with a greater number of meta-analysis published in the literature were: psychiatry, oncology and cardiology. Diffusion of knowledge about fundamentals and methodology of meta-analysis seems to have drawn and increase in performing and reporting this kind of analysis.

Evidence-Based Medicine↗
PubMed1998

[Secondary encephalopathy due to exposure to organic solvents: psychopathological, neuropsychological and neuroimaging findings].

Chronic exposure to organic solvents may cause permanent cognitive impairment. The nonspecify of neurological signs as the abnormalities of neurophysiological tests and morphological neuroimaging techniques have oblige the use of clinic neuropsychology in the monitorization of the neurotoxicity cause by these substances. The new modern functional neuroimaging techniques can contribute to the diagnosis of brain lesions caused by the exposure to organic solvents. We report a case that clearly supports this hypothesis as we emphasize the correlation found between clinical symptoms and the deficits obtained after the study of cerebral blood flow with single photon emission computed tomography (SPECT).

Adult↗
PubMed1997

Cavernous hemangioma of the liver. Diagnostic value of 99mTc-labeled red cell scintigraphy: results in 28 patients.

Cavernous hemangioma is the most common benign tumor of the liver, the organ in which these lesions are most often present. We report on 28 patients who underwent 99mTc-labeled red cell scintigraphy after ultrasound or computerized tomography images suggesting the existence of one or more hepatic angiomas. In 16 patients (57.1%), an accumulation of red blood cells was considered to indicate the existence of hemangiomas. On the basis of subsequent clinical follow-up, ultrasound studies, and in one case laparotomy, all were eventually confirmed to be hemangiomas. The specificity as 100%. In the remaining 12 patients (42.9%), red cell uptake was not observed and the findings were considered negative; in this group, there were 10 true negatives and 2 false negatives in which scintigraphy failed to detect the existing angiomas due to their small size and deep location. The sensitivity was 88.8%. On the basis of the results, it is concluded that labeled red cell scintigraphy is a highly sensitive and specific method for the diagnosis of cavernous hemangioma of the liver. It should be considered the method of choice when this lesion is suspected, thus avoiding the use of more invasive diagnostic procedures such as laparoscopy which, in our study proved to be unnecessary.

Adult↗
PubMed1997

Primary malignant fibrous histiocytoma of the jejunum: report of a case and review of subject.

We report a new case of primary malignant fibrous histiocytoma of the jejunum. Malignant fibrous histiocytoma (MFH) occurs most commonly in the extremities and trunk, but rarely in visceral organs. However, only eight cases of primary tumours involving the small intestine, including the present, have been described. This case report documents the appearance of malignant fibrous histiocytoma as a primary lesion of the intestinal wall in a patient with a 2-month history of dyspepsia, weight loss and unspecific abdominal pain. The final diagnosis was based on the pathological report of the surgical specimen. Emphasis is placed on the clinical signs, radiological studies and pathological findings. The literature on MFH of the jejunum is also reviewed. Malignant fibrous histiocytoma is considered an aggressive tumour, and the treatment of choice is complete surgical excision. Adjuvant chemotherapy or radiation is recommended mainly in those patients in whom there is vascular or lymphatic infiltration.

Combined Modality Therapy↗
PubMed1997

[Chronic schizophrenia: validity of the study of regional cerebral blood flow through cerebral SPECT].

OBJECTIVE: To check the validity of the diagnostic test in schizophrenia. MATERIAL AND METHODS: The cerebral blood flow (CBF) characteristics were assessed by means of single photon emission tomography (SPECT) in 24 patients with schizophrenia and 20 normal control subjects. Analysis of sensitivity, specificity and the Youden rate was made of certain RCBF patterns chosen in terms of the cerebral regions between which the greatest differences were observed according to the diagnosis, schizophrenia vs control. RESULTS: Schizophrenia vs control: sensitivity = 58.33%; specificity = 95%; positive predictive value = 93.33% and overall efficiency = 53.33%. CONCLUSIONS: Cerebral SPECT is valid in the discrimination between patients diagnosed with schizophrenia and control subjects, taking the diagnostic judgement of the psychiatrist as the gold standard, and the RCBF pattern that displays the best coefficient is hypoperfusion, in one or several of the regions: right frontal/left frontal/right parietal/thalamus: sensitivity = 58.33%; specificity = 95%; positive predictive value = 93.33% and overall efficiency = 53.33%.

Adolescent↗
PubMed1997

[Contribution of hepatic scintigraphy with Tc99m blood cells to the imaging diagnosis of cavernous hemangioma. Results in 48 patients].

Cavernous hemangiomas are the most common benign tumours of the liver, being the liver the most frequent organ affected by this lesions. We report 48 patients who underwent 99mTc-red blood cell (RBC) scintigraphy, after ultrasound or tomographic appearance of cavernous hemangioma. Scintigraphy findings in 29 of 48 patients (60.4%) were typical of cavernous hemangioma, hemangioma-positives, after scintigraphy (all true-positives). On clinical, ultrasound and in one case after surgery (exploratory laparotomy) the follow up was positive for hemangioma. Specificity of 100%. In the remaining 19 patients (39.6%) where hemangioma-negative lesions, 17 of 19 where true negatives and the remaining 2 where angiomas false-negatives, both of them were small lesions. The sensitivity for hemangiomas was 89.4%. To conclude with we would like to enhance the high specificity and sensitivity of 99mTc-red blood cell scintigraphy on the diagnosis of cavernous hepatic hemangioma (CHH). We highlight the utility of this specific imaging technique in the final diagnosis of CHH not requiring other invasive diagnosis tests, such as laparoscopy that in our study proved to be unnecessary.

Adult↗
PubMed1991

Sister chromatid exchanges, proliferating rate index, and micronuclei in biomonitoring of internal exposure to vinyl chloride monomer in plastic industry workers.

The frequency of micronuclei (MN), sister chromatid exchange (SCEs), and the proliferating rate index in peripheral blood lymphocytes from 93 individuals were measured. Fifty-two of the individuals were workers in the plastics industry where they were exposed to vinyl chloride monomer while the remaining 41 individuals served as a control group. In our results, an increase of SCEs and MN, as well as inhibited cell kinetics, was observed in the group of exposed workers. Of the tests used, SCE was found to be the most sensitive endpoint for indicating a biological response. However, since methods for restricting the MN analysis to only cells at risk (i.e., second generation interphase cells) were not used, this statement requires verification.

Adolescent↗
PubMedDate not supplied

Inhibition of allospecific response in pancreatic islet transplantation: the glycan approach.

UNLABELLED: Host resistance has precluded clinical islet transplantation from becoming a consistent therapy for type I diabetic patients, mainly due to both specific and nonspecific processes. O-glycosylated proteins have a primary role in immunologic synapses. Therefore, we investigated the effects of a putative immunomodulatory effect of the cleavage of these molecules on islet allotransplantation. METHODS: Murine islets were treated with O-sialoglycoprotein endopeptidase. Three endpoints were studied: (1) proliferation in allogeneic mixed islet mononuclear cell reactions using treated and control irradiated islets as stimulator cells of mononuclear cells; (2) expression of IA-d on monocytes using 48-hour transplants of treated versus control mouse islets into subcutaneous capsules; (3) posttransplant graft function in an in vivo model of islet allotransplantation. Treated and control islets were transplanted in diabetic mice treated daily with cyclosporine. Glycemia was monitored to determine diabetes reversion. RESULTS: The allogeneic proliferative response was maximal when allogeneic mononuclear cells were mixed with control islets; it was significantly decreased with treated islets. Mean proliferative inhibition rate of treated vs. control was 62%. IA-d expression on monocytes was maximal in control islets. Reversion was significantly different for treated versus control islets with its duration varied from 3 to 7 days. CONCLUSION: These results suggest that treatment of islets with O-sialoglycoprotein endopeptidase may modulate allogeneic immunologic reactions.

Animals↗
PubMedDate not supplied

[Neurological sciences based on evidence].

OBJECTIVE: An exhaustive search of reported metanalysis from any medical speciality is described. MATERIAL AND METHODS: Search of papers included in MEDLINE or EMBASE between 1973-1998. A descriptive analysis of the reported papers (frequency tables and graphics) is described, including differences of mean of reported metanalysis papers by medical speciality and year. RESULTS: 1,514 papers were selected and classified. Between 1977-1987 overall mean of reported studies of neurologic metanalysis (1.20 +/- 1.10) was significatively inferior to the 1988-1998 (11.20 +/- 7.85) (p < 0.001). Global number of neurologic metanalysis was positively correlated (p < 0.05) with the number of studies about fundamentals and methodology during the study period. CONCLUSIONS: A progressive increase in the number of reported neurologic metanalysis since 1977 can be demonstrated. Diffusion of knowledge about fundamentals and methodology of metanalysis seems to have drawn and increase in performing and reporting this kind of analysis.

Evidence-Based Medicine↗
PubMedDate not supplied

[Impact of meta-analysis in clinical practice: the example of psychiatry].

BACKGROUND: To analyze the features of the studies on meta-analysis in psychiatry and assess the effect of these papers on the psychiatric reference textbooks. METHODS: Two researchers reviewed electronic databases Medline and Embase during the period 1977-98, using the key words: clinical trial, randomized observational trial, metaanalysis, systematic review. To confirm the validity of the searching strategy inter and intra-raters reliability was studied with satisfactory kappa figures. RESULTS: Psychiatry is the medical specialty in which more studies on meta-analysis have been carried out (N= 179, 11,79% out of the total), followed by cardiology and oncology. The increase in this kind of research during 1977-98 has been very high in all medical fields and, specifically, in psychiatry. There is no correlation between impact factor of a scientifical journal and number of meta-analysis published in it. Only 0.002% of the references of one of the most important textbook in psychiatry (Kaplan) are related to meta-analysis. There is no studies on meta-analysis developed by Spanish researchers. CONCLUSIONS: Studies on meta-analysis are not referred by psychiatric reference textbooks. As a consequence, their impact on clinical practice is scarce.

Meta-Analysis as Topic↗