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Biomedical subjects

A Maldonado

Publications and source records attributed to A Maldonado.

At least 37 records · Page 2Linked to original sources
PubMed2000

Clinical Impact of 18F-FDG-PET in the Suspicion of Recurrent Ovarian Carcinoma Based on Elevated Tumor Marker Serum Levels.

Purpose: To retrospectively evaluate the contribution of 18F-fluorodeoxy-glucose-positron emission tomography (FDG-PET) to the diagnosis and clinical management of patients who were suspected of recurrent ovarian carcinoma, based on elevated tumor markers levels with normal or equivocal computed tomography (CT) or nuclear magnetic resonance (NMR).Procedures: 20 patients with these characteristics underwent FDG-PET. PET findings were confirmed in 14, in 7 by surgery, and in the other 7 by clinical course.Results: Recurrence was confirmed in 12 patients, all with FDG-PET positive. In other 2, recurrence was rule out and in 1, FDG-PET was negative. FDG-PET accuracy was 93% with 4 surgeries avoided and guided other 6.Conclusions: FDG-PET is an useful technique for detecting recurrent ovarian carcinoma suspected by elevated tumor markers levels and normal or equivocal results in the morphologic imaging techniques and has an important clinical impact on the management of these patients.

Journal Article↗
PubMed2000

Comparison of systemic cytokine levels in patients with acute respiratory distress syndrome, severe pneumonia, and controls.

BACKGROUND: The inflammatory response has been widely investigated in patients with acute respiratory distress syndrome (ARDS) and pneumonia. Studies investigating the diagnostic values of serum cytokine levels have yielded conflicting results and only little information is available for the differential diagnosis between ARDS and pneumonia. METHODS: Clinical and physiological data, serum concentrations of tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6, and quantitative cultures of lower respiratory tract specimens were obtained from 46 patients with ARDS and 20 with severe pneumonia within 24 hours of the onset of the disease and from 10 control subjects with no inflammatory lung disease. Cytokine concentrations were compared between groups and determinants in addition to the diagnosis were tested. RESULTS: Serum TNF-alpha levels were significantly higher in ARDS patients (67 (57) pg/ml) than in patients with severe pneumonia (35 (20) pg/ml; p = 0.031) or controls (17 (8) pg/ml; p = 0.007). For IL-1beta and IL-6 the observed differences were not statistically significant between patients with ARDS (IL-1beta: 34 (65) pg/ml; IL-6: 712 (1058) pg/ml), those with severe pneumonia (IL-1beta: 3 (4) pg/ml, p = 0.071; IL-6: 834 (1165) pg/ml, p = 1.0), and controls (IL-1beta: 6 (11) pg/ml, p = 0.359; IL-6: 94 (110) pg/ml, p = 0.262). TNF-alpha (standardised coefficient beta = 0.410, p<0.001) and IL-1beta (standardised coefficient beta = 0.311, p = 0.006) were most strongly associated with the degree of lung injury, even when the diagnostic group was included in the statistical model. CONCLUSIONS: Serum TNF-alpha levels were higher in patients with ARDS than in those with severe pneumonia or in control subjects. Multivariate results suggest that the levels of systemic TNF-alpha and IL-1beta reflect the severity of the lung injury rather than the diagnosis.

Biomarkers↗
PubMed2000

Capnometric recirculation gas tonometry and weaning from mechanical ventilation.

The aim of this study was to describe changes in regional intramucosal PCO(2) (Pr(CO(2)) measured with capnometric recirculation gas tonometry [CRGT]) in patients with acute respiratory failure, who proceed from mechanical ventilation to weaning. In addition, we compared the predictive power for the weaning outcome of CRGT measurements obtained during mechanical ventilation to the frequency/ tidal volume (f/VT) ratio. A total of 24 patients (31 weaning trials) were included in the study, but four of the 24 patients (17%) were excluded because of extubation failure. Of the remaining 27 weaning trials in 20 patients, 12 (44%) were unsuccessful. Changes observed in patients with weaning failure (increase in Pr(CO(2)) from 60.4 +/- 15.0 mm Hg in mechanical ventilation to 67.4 +/- 21.0 mm Hg, in weaning) were significantly different (p = 0.046) from those observed in patients with weaning success (fall in Pr(CO(2)) from 61.5 +/- 15.0 mm Hg in mechanical ventilation to 56.3 +/- 16.7 mm Hg in weaning). However, absolute values of Pr(CO(2)) were not significantly different between patients with weaning success and failure, neither during mechanical ventilation (success, 61.5 +/- 15.0 versus failure, 60.4 +/- 15.0 mm Hg, p = 0.848) nor during weaning (success, 56.3 +/- 16.7 versus failure, 67.4 +/- 21.0 mm Hg, p = 0.135). The best single predictor for weaning outcome was the f/VT ratio measured early during weaning (area under the curve: 0.844 +/- 0.081; adjusted odds ratio for threshold value </= 105: 42.0, 95% CI 3.8 to 469.1, p = 0.002). CRGT could confirm a significant increase in Pr(CO(2)) during weaning in patients who finally failed the weaning trial. However, differences between patients with weaning success and failure were small and CRGT did not replace or improve the predictive power of the f/VT ratio for weaning outcome.

Acute Disease↗
PubMed2000

[Evaluation of the tuberculin reaction in health occupation students] .

A cross-sectional study was done at the University of Antioquia, MedellIn, Colombia, to evaluate the response to a tuberculin skin test among students in undergraduate health programs (medicine, odontology, nursing, and bacteriology) as compared to undergraduate students in nonhealth programs. The study included students from the beginning, middle, and end of the university's academic programs. The sample of 490 students included 273 from health programs and 217 from nonhealth programs. Participants were randomly selected using lists provided by the university registrar, for the second semester of 1998. The presence of a BCG vaccination scar was determined, and all the participants were also questioned about TB-related risk factors. Tuberculin skin test reactivity was evaluated by the size of induration 72 hours after intradermal injection of two tuberculin units of purified protein derivative RT 23. There were no differences in tuberculin reactivity between students from the health programs and from the nonhealth programs, irrespective of the academic level. However, there was a significantly higher proportion of positive skin tests among students with a BCG scar. These results suggest that undergraduate health students do not have extensive contact with TB patients or with clinical samples from such patients. Nevertheless, the results do not rule out TB as an occupational risk for health personnel.

Adult↗
PubMed2000

[Role of the positron emission tomography (PET) in suspected tumor recurrence when there is increased serum tumor markers].

PURPOSE: Evaluate the usefulness of Positron Emission Tomography with 18F-Fluorodeoxyglucose (FDG-PET) to detect lesions when tumor recurrences are suspected due to the progressive increase of tumor markers and the study of their extension with negative or non-conclusive morphostructural diagnostic techniques. MATERIAL AND METHODS: Whole body FDG-PET was per-formed in 72 patients with different cancer diseases, 23 of whom had breast, 18 colorectal, 15 thyroid, 6 lung, 3 ovarian cancer and 7 had other types of cancers. Tumoral recurrence was suspected in all of the cases due to the progressive marker increase and negative or non-conclusive conventional studies. RESULTS: FDG-PET detected lesions in 85% patients, 33% of which were confirmed by the end of the study. In 40% of all cases, therapeutics measures were applied, 14% of which consisted in surgery with intention to cure. Sensitivity, specificity and accuracy were 96.4%, 75.6% and 93.9% respectively. CONCLUSIONS: Whole body FDG-PET is an accurate procedure in diagnosis of recurrent tumoral disease in patients with rising tumoral marker levels and with negative conventional morphostructural extension studies, and can make it possible to change the therapeutic approach in some cases.

Biomarkers, Tumor↗
PubMed1999

Functional blockade of the parabrachial area by tetrodotoxin disrupts the acquisition of conditioned taste aversion induced by motion-sickness in rats.

The role of the parabrachial area in conditioned taste aversion (CTA) induced by motion-sickness was studied in male Wistar rats. In the first experiment, one-trial conditioned taste aversion, to a 0.5% decaffeinated coffee solution, was induced by 30 min of vertical rotatory motion (80 rev./min) in intact rats. In the second experiment, reversible blockade of the neural activity in various brainstem sites was induced by bilateral intracerebral injections of tetrodotoxin (TTX) (10 ng/microl) after conditioning. Blockade of the parabrachial area, but neither A8 nor lateral vestibular nucleus, disrupted the acquisition of (CTA). The results are discussed in terms of an associative role of the parabrachial area in body rotation-induced taste aversion learning, as the area was intact during sensory processing and testing.

Analysis of Variance↗
PubMed1999

Identification of caveolae and caveolin in C6 glioma cells.

Caveolae (CAV) constitute a novel subcellular transport vesicle that has received special attention based on its proven and postulated participation in transcytosis, potocytosis, and in cell signaling events. One of the principal components of CAV are caveolin protein isoforms. Here, we have undertaken the immunochemical identification of CAV and the known caveolin isoforms (1alpha, 1beta, 2 and 3) in cultured rat C6 glioma cells. Immunoblot analysis revealed that particulate fractions from rat C6 glioma cells express caveolin-1 and caveolin-2. The relative detergent-insolubility of these caveolin isoforms was also determined by Western blot analysis. Indirect immunofluorescence analysis with caveolin-1 and -2 antibodies revealed staining patterns typical of CAV's known subcellular distribution and localization. For both caveolin isoforms immunocytochemical staining was characterized by intensely fluorescent puncta throughout the cytoplasm and diffuse micropatches at the level of the plasmalemma. Perinuclear staining was also detected, consistent and suggestive of caveolin's localization in the trans Golgi region. The caveolin-1 and -2 immunoreactivity seen in Western blots and immunocytochemically is related to structurally relevant CAV as supported by the isolation of caveolin-enriched membrane complexes using two different methods. Light-density, Triton X-100-insoluble caveolin-1- and caveolin-2-enriched fractions were obtained after fractionation of rat C6 glioma cells and their separation over 5-40% discontinuous sucrose-density gradients. Similar fractions were obtained using a detergent-free, sodium carbonate-based fractionation method. These results further support the localization of CAV and caveolins in glial cells. In addition, they demonstrate that cultured C6 glioma cells can be useful as a model system to study the role of CAV and caveolins in subcellular transport and signal transduction events in glial cells and the brain.

Animals↗
PubMed1999

Outbreak of septicaemic colibacillosis in Japanese quail (Coturnix coturnix japonica).

We have carried out an aetiological and pathological study of an outbreak of septicaemia caused by the O165 serogroup of Escherichia coli in Japanese quail (Coturnix coturnix japonica) which resulted in high mortality (90%). After treatment with amoxicilin in drinking water (200 mg/l), morbility and mortality rates dropped markedly. Microbiological studies showed that the organism responsible was an atypical E. coli strain, on the basis of the non-fermentation of lactose (ONPG-), which belonged to the O165 serogroup and was highly virulent for 1-day-old chickens.

Animals↗
PubMed1999

Oestrogens regulate pituitary alpha2,3-sialyltransferase messenger ribonucleic acid levels in the female rat.

Follicle-stimulating hormone (FSH) is synthesized by the anterior pituitary gland in multiple molecular forms. Increased acidic/sialylated FSH charge isoforms are associated with conditions characterized by a low oestrogen output. In the present study, we analysed the dynamics of the changes in mRNA levels of the enzyme Galbeta1,3[4]GlcNAc alpha2,3-sialyltransferase (2,3-STase) (one of the enzymes that incorporate sialic acid residues into the FSH molecule) in intact and ovariectomized rats. The anterior pituitaries of 4-day regularly cyclic adult female Wistar rats were obtained at 1000 h on the days of pro-oestrus (P), oestrus (O), dioestrus 1 (D1) and dioestrus 2 (D2), at 0200 h, 1400 h, 1800 h and 2200 h on D1, at 1800 h on day of O and at 1000 h after 7, 14, 21, 28 and 45 days of oophorectomy performed on the morning of P. Total RNA was isolated from each gland and the 2,3-STase levels were measured by Northern blot hybridization analysis employing a 346-base pair cDNA probe encoding for a non-conserved amino acid sequence of the catalytic domain of the enzyme. Maximal levels of the enzyme mRNA were detected at 1000 h on D1; thereafter, they progressively decreased by 60% during the ensuing 24 h, reaching the lowest concentration values (26% of the maximally observed level on D1) at 1000 h on day of P and remaining unchanged during the morning of O. Administration of the potent oestradiol receptor antagonist ICI 182,780 at 1000 h on D1 completely reverted the time-dependent decrease in 2,3-STase mRNA levels observed during the afternoon of D1, whereas oestradiol benzoate administered at 1000 h on day of O significantly reduced the enzyme mRNA levels (to 21% of the levels detected in vehicle-treated controls). In ovariectomized rats, the alpha2,3-STase mRNA progressively increased from day 21 to day 45 post castration. Administration of oestradiol benzoate on day 28 after oophorectomy significantly reduced the 2,3-STase mRNA levels (to 36% of the levels detected in vehicle-injected controls); ICI 182,780 partially counteracted this oestradiol-mediated effect. The dynamics of these changes in 2,3-STase mRNA levels partially correlated with changes in the relative abundance of the FSH charge isoforms separated by preparative chromatofocusing of anterior pituitary extracts, particularly in glands obtained during the morning of P and O. These data demonstrate for the first time that pituitary 2,3-STase is a hormonally-regulated enzyme and that the changes in transcription and/or stability of its mRNA may be involved, in part, in the post-translational processing of the FSH molecule during certain physiological conditions.

Animals↗
PubMed1999

[PET-FDG in thyroid cancer with high thyroglobulin levels and negative 131-I scan. A case report].

The value of whole body PET-FDG in the evaluation of metastases has been demonstrated in a wide variety of tumors. In this report, we present the case of a patient with antecedent of papillary thyroid carcinoma, who was operated twelve years ago, and submitted to an ablative dose of residual thyroid tissue through 131I, being the levels of thyroglobulin normals. After twelve years of evolution, the patient refers bag pain and respiratory trouble, appearing in the CT image suspicious of metastases in right pulmonary base. The levels of thyroglobulin were shown increased, being the 131I scan negative. A whole body PET-FDG study was performed in order to exclude metastases of his malignant process, showed multiple high FDG uptake focus in brain, cerebellum, neck, chest, lymphatic nodes and bone, suggestive of dedifferentiated disease These findings were confirmed subsequently in the clinic evolution. Therefore, whole-body PET-FDG is a complementary diagnostic technique for study patients with CDT (Thyroid Differentiated Carcinoma) with 131I scan negative and rising thyroglobulin levels.

Aged↗
PubMed1999

[Stereotypes, developmental disorders and neuroimaging studies].

INTRODUCTION: We believe that it is of great interest, in neuropediatric clinic, to value the molar behavior disorders and to accomplish the corresponding molecular alterations in the central nervous system. PATIENTS AND METHODS: We studied 26 patients diagnosed of serious disorders of the development, that were presenting a typical clinic with manual stereotypes. We choose at random 5 children to practice them a study of metabolic neuroimaging through the Positron Emission Tomography with 18Fluoro-Deoxi-Glucose (PET-FDG). RESULTS AND CONCLUSIONS: The conclusion, more meaningful, is that the children with serious disorders of the development present a mature failure in the neuro-function circuits of the thalamus, as well as the cortical connection and association areas. This clinical situation is reinforced by the results of the PET-FDG, that presents a characteristic metabolic image of the autism children, with a bilateral decrease of the capitation of FDG, mainly in regions as thalamus, frontal and temporary lobes.

Adolescent↗
PubMed1998

Trough to peak ratio of once-daily lisinopril and twice-daily captopril in patients with essential hypertension.

The objective of this study was to assess the antihypertensive effect and the trough to peak (T:P) ratio of lisinopril and captopril, in patients with essential hypertension. After 2 weeks of placebo, 69 of 115 eligible patients had office diastolic blood pressure (DBP) between 90 and 114 mm Hg and daytime average DBP above 85 mm Hg during a 25-h ambulatory BP monitoring (ABPM) and were randomised to receive lisinopril (20 mg once daily) or captopril (50 mg twice daily) for 4 weeks. Office and ambulatory BP were then repeated. Indices of 24-h BP and T:P ratios were calculated and compared. Both drugs significantly reduced both office and ambulatory BP. The final BP obtained with lisinopril was less than with captopril. On office measurement, 75% of the patients treated with lisinopril and 44% on captopril were controlled (P < 0.001), but responses by ABPM were not significantly different. T:P ratios calculated in all patients were 0.75 and 0.66 for lisinopril and captopril respectively, but in patients who responded to each drug the corresponding ratios were 0.78 and 0.73. In conclusion both 20 mg once-daily lisinopril and 50 mg captopril twice-daily achieve a favourable T:P ratio in patients with essential hypertension.

Adult↗