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Biomedical subjects

S Romero

Publications and source records attributed to S Romero.

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

Light's criteria revisited: consistency and comparison with new proposed alternative criteria for separating pleural transudates from exudates.

OBJECTIVES: The first objective was to assess the diagnostic value of new biochemical criteria proposed to discriminate pleural transudates from exudates and to compare their efficiency with those of Light's criteria. The second objective of the study was to assess the interstudy variability of the parameters repeatedly determinated in two different groups of patients with pleural effusion. PATIENTS AND METHODS: We recorded clinical characteristics and final diagnoses and measured pleural fluid (PF) and serum levels of protein, LDH, cholesterol and cholinesterase of 243 patients with pleural effusion. RESULTS: Sixty-one (25%) pleural effusions were transudates and 182 were exudates. The sensitivity (99%) and accuracy (96%) of Light's criteria were higher than those of the other criteria tested, although the differences with those of the PF LDH-cholesterol combination (96 and 93%) did not show statistical significance. Pleural LDH concentration was the criterion with the highest specificity (95%), being significantly higher (p < 0.05) than that of Light's criteria. The sensitivity, specificity and accuracy of most criteria tested did not vary when compared with those obtained in a study performed 5 years previously. CONCLUSIONS: Light's criteria remain the criteria of choice for segregating exudates from transudates. Based on cost-efficiency reasons, the PF LDH-cholesterol combination appears as an alternative. Because both sets of criteria misdiagnose a substantial percentage of transudates, exceptions based on good clinical judgment and the complementary use of a more specific criterion, as the PF concentration of LDH, must be considered.

Adolescent↗
PubMed2000

Malignant transient pleural transudate: a sign of early lymphatic tumoral obstruction.

In the absence of a responsible comorbid condition, the transudative character of a pleural effusion in patients with malignancy does not imply a favorable outcome. We report a case of colon carcinoma metastatic to lung and pleura presenting as a bilateral transudative pleural effusion. Tumoral diffuse lymphatic permeation was identified as the cause of lymphatic obstruction on pleural and transbronchial biopsies. The transudative character of the pleural effusion was transient denoting its obstructive origin.

Adenocarcinoma↗
PubMed2000

Multiple solubility maxima of oxolinic acid in mixed solvents and a new extension of Hildebrand solubility approach.

A new extension of the Hildebrand solubility approach which describes drug solubility in solvent mixtures showing multiple solubility peaks, the chameleonic effect, is proposed. The experimental solubilities of oxolinic acid were measured at 25 degrees C in solvent mixtures of ethanol-water and ethanol-ethyl acetate. A plot of the mole fraction of the drug against the solubility parameter (delta) of the solvent mixtures displays two peaks at delta = 30.78 MPa1/2 (80% v/v of ethanol in water) and at delta = 20.90 MPa1/2 (30% v/v of ethanol in ethyl acetate). The new extension proposed reproduces two solubility peaks. The thermograms of the solid phase before and after equilibration with the solvent mixtures did not show significant changes. The new extension was also tested with experimental data previously reported for drugs showing two solubility peaks of different height. The accuracy of other published models for describing two solubility maxima is also compared.

Algorithms↗
PubMed2000

Hypertrophic osteoarthropathy in lung cancer: are the radiographic bone changes reversible after curative resection?

Lack of relief of bone and joint pains and persistence of the radiographic abnormalities in patients with secondary hypertrophic osteoarthropathy, after lung tumour removal, are considered as signs of an unfavourable prognosis. Two patients are documented in whom the lack of reversion of periosteal changes after tumour removal was compatible with a favourable long-term prognosis, suggesting that radiographic exploration is an insensitive technique to appreciate involutive bone changes occurring in these patients.

Aged↗
PubMed1999

Solubility behavior of polymorphs I and II of mefenamic acid in solvent mixtures.

The dissolution profile and solubility of two polymorphic forms of mefenamic acid were studied in solvent mixtures of ethanol-water and ethyl acetate-ethanol. The solubility parameter (delta) was used to study the effect of polarity on the solubility behavior of the two polymorphs. Differential scanning calorimetry and infrared spectroscopy were performed on the original powders and on the solid phases after contact with the solvent systems for the characterization and identification of the polymorphs. The dissolution rates of both polymorphs is greater in the less polar mixtures (ethyl acetate-ethanol) of lower solubility parameter values. Form II showed larger dissolution rates and saturation concentrations than Form I in all the solvent systems studied. The solid phase of Form II converts totally to Form I after equilibration with the solvents. The rate of conversion was faster in the least polar mixtures. The solubility of both polymorphs reaches a single maximum at 80% ethyl acetate in ethanol, delta = 20.09 MPa1/2. The modified extended Hildebrand method was used to predict the solubility profile of each polymorph. A single equation was obtained for both polymorphs which includes the solubility parameter of the mixtures and the logarithm of the solubility mole fraction of each polymorph in water. The Hildebrand solubility parameter of mefenamic acid is independent of the crystalline form and was determined from two methods giving quite similar values, delta 2 = 20-21 MPa1/2.

Acetates↗
PubMed1999

Bilateral lymphocytic alveolitis: a common reaction after unilateral thoracic irradiation.

The main aim of the present study was to assess the early diagnostic value of bronchoalveolar lavage (BAL) in radiation-induced lung injury in patients with breast carcinoma. Twenty-six females receiving postoperative radiotherapy for breast cancer were evaluated before and 0, 15, 30, 60, and 180 days after radiotherapy. History, physical examination, chest radiographs, and pulmonary function tests were obtained. BAL, including lymphocyte subsets analysis, was limited to the second evaluation after radiotherapy. A group of 21 healthy females were used as control. Findings after radiotherapy in asymptomatic patients were compared with findings in a group of patients with radiation pneumonitis. Irradiated patients showed a significantly (p<0.01) greater percentage (29.5+/-15.7%) of BAL lymphocytes than controls (6.2+/-3.3%). No statistical differences existed in BAL findings between the irradiated and unirradiated sides of the chest. Percentages of BAL lymphocytes did not differ significantly between patients who developed subsequent pneumonitis (24.5+/-13.5%) and those who did not develop pneumonitis (32.8+/-16.5%). Patients with pneumonitis at the time of BAL had significantly higher (p<0.05) alveolar CD4 subset cells (24.8+/-10.2%) than asymptomatic patients (15.2+/-8.9%). Maximal reductions in total lung capacity (p<0.01), and residual volume (p<0.05) occurred 60 days after irradiation. The early lymphocytic alveolitis induced by unilateral thoracic radiotherapy in most patients with breast cancer is always bilateral and does not predict the subsequent development of radiological evidence of pneumonitis.

Breast Neoplasms↗
PubMed1999

Enteropathogens and other factors associated with severe disease in children with acute watery diarrhea in Lima, Peru.

To evaluate enteropathogens and other factors associated with severe disease in children with diarrhea, 381 children <5 years of age with diarrhea and moderate to severe dehydration (in-patients) and 381 age-, sex-, and date-of-visit-matched children with mild diarrhea (out-patients) presenting to a hospital in Peru, were studied. Rotavirus was detected in 52% of the in-patients and 35% of the out-patients (odds ratio [OR]=2.3, 95% confidence interval [95% CI]= 1.6-3.2); 95% of the rotaviruses among in-patients were of serotypes G1-G4. The risk of severe diarrhea was particularly great in children who were not exclusively breast-fed in early infancy and who also lacked piped water in their homes (for children with both characteristics OR=6.8, 95% CI=3.6-12.8). The high prevalence of rotavirus and its association with severe diarrhea underscores the need for rotavirus vaccines. Interventions to educate mothers and improve access to safe water should augment the impact of rotavirus vaccines in preventing severe diarrhea.

Animals↗
PubMed1999

Hemorheological profile in chronic venous insufficiency after surgery.

In recent years, there have been rheological abnormalities reported in chronic venous insufficiency (CVI), mainly an increase of erythrocyte aggregability (EA), which probably take part in the pathophysiology of the disease. The aim of this study was to analyze the hemorheological profile after stripping in 45 patients suffering from CVI. Follow-up included laboratory tests on the 7th, 60th and 180th day after surgery. EA was assessed with a photometric aggregometer (MA1, Myrenne) in stasis and low shear (3 s(-1)). The results show an increase of EA on the 7th day after surgery (p<0.001). Two and 6 months later, EA values returned to those found prior to surgery. The plasma fibrinogen level changes in a way parallel to EA. The association between rheological disturbances and thrombogenesis is well known, so the hyperaggregability found supports the antithrombotic prophylaxis in the early postsurgical period. On the other hand, the hemorheological abnormalities persist after stripping, so postsurgical treatment to inhibit EA may be beneficial.

Adult↗
PubMed1999

Ethanol effect on the chick embryo ossification: a macroscopic and microscopic study.

This study attempts to analyze anomalies in avian embryos induced macroscopically and microscopically when exposed to ethanol (EtOH) during the first stages of development. Fertilized chicken eggs were employed in this study. The eggs were incubated at 37.8 degrees C. Some of the eggs were treated on day 0 with EtOH (20%, 40% and 60%) by instillation in the air sac. The control group was instilled with 0.1 ml of NaCl at 0.9%. Other eggs were treated on the 4th post-incubation day, employing the same methodology. The embryos in both groups were removed from the eggs on the 11th incubation day and examined using a dissecting binocular microscope. After macroscopic analysis, the samples obtained were fixed in 10% formol, photographed and processed according to common histological techniques and the Picrosirius method. Embryos treated with EtOH demonstrated a significant weight decrease. Microscopic analysis by means of the Picrosirius method revealed that the intra-membranous ossification process presents less development, and therefore there was less type I collagen in trabecular bone in the embryos post-exposure to EtOH with respect to the control.

Abnormalities, Drug-Induced↗
PubMed1998

Enthalpy-entropy compensation for the solubility of drugs in solvent mixtures: paracetamol, acetanilide, and nalidixic acid in dioxane-water.

In earlier work, a nonlinear enthalpy-entropy compensation was observed for the solubility of phenacetin in dioxane-water mixtures. This effect had not been earlier reported for the solubility of drugs in solvent mixtures. To gain insight into the compensation effect, the behavior of the apparent thermodynamic magnitudes for the solubility of paracetamol, acetanilide, and nalidixic acid is studied in this work. The solubility of these drugs was measured at several temperatures in dioxane-water mixtures. DSC analysis was performed on the original powders and on the solid phases after equilibration with the solvent mixture. The thermal properties of the solid phases did not show significant changes. The three drugs display a solubility maximum against the cosolvent ratio. The solubility peaks of acetanilide and nalidixic acid shift to a more polar region at the higher temperatures. Nonlinear van't Hoff plots were observed for nalidixic acid whereas acetanilide and paracetamol show linear behavior at the temperature range studied. The apparent enthalpies of solution are endothermic going through a maximum at 50% dioxane. Two different mechanisms, entropy and enthalpy, are suggested to be the driving forces that increase the solubility of the three drugs. Solubility is entropy controlled at the water-rich region (0-50% dioxane) and enthalpy controlled at the dioxane-rich region (50-100% dioxane). The enthalpy-entropy compensation analysis also suggests that two different mechanisms, dependent on cosolvent ratio, are involved in the solubility enhancement of the three drugs. The plots of deltaH versus deltaG are nonlinear, and the slope changes from positive to negative above 50% dioxane. The compensation effect for the thermodynamic magnitudes of transfer from water to the aqueous mixtures can be described by a common empirical nonlinear relationship, with the exception of paracetamol, which follows a separate linear relationship at dioxane ratios above 50%. The results corroborate earlier findings with phenacetin. The similar pattern shown by the drugs studied suggests that the nonlinear enthalpy-entropy compensation effect may be characteristic of the solubility of semipolar drugs in dioxane-water mixtures.

Acetaminophen↗
PubMed1998

Organizing pneumonia in textile printing workers: a clinical description.

In April 1992 an outbreak of severe respiratory illness occurred among aerographic textile workers in the area of Alcoi, Autonomous Community of Valencia, Spain. An epidemiological study linked this outbreak to the use of a reformulated aerosolized product, Acramin-FWN. We analyzed clinical, laboratory, and pathological data of the first 14 patients with confirmed organizing pneumonia (OP) secondary to this newly recognized occupational toxicant. The mean age of the patients was 30 yrs. The most common clinical findings were cough (86%), epistaxis (71%), dyspnoea (64%), oppressive chest pain (57%), and crackles (50%). A restrictive functional pattern was evident in 64%. Radiographic findings consisted predominantly of patchy infiltrates in 65% and a micronodular pattern in 35%. Treatment with corticosteroids did not prevent initial progression in 11 of the 14 patients and development of irreversible respiratory failure in five patients. At necropsy, besides features of OP, interstitial fibrosis and diffuse alveolar damage were evident. A low total lung capacity, the presence of crackles at admission, and increases in the alveolar-arterial oxygen difference were predictive of death. The organizing pneumonia caused by the inhalation of Acramin-FWN is characterized by a tendency to evolve into progressive interstitial fibrosis despite the use of corticosteroids. The illness is restricted to the respiratory system and once respiratory failure has developed the prognosis is poor.

Adipates↗
PubMed1998

Chylothorax in cirrhosis of the liver: analysis of its frequency and clinical characteristics.

OBJECTIVES: To ascertain the frequency and to describe the clinical and biochemical features of cirrhotic chylothorax. DESIGN: A descriptive clinical study. SETTING: A community teaching hospital. PATIENTS AND METHODS: Since November 1989 to October 1995, 809 patients with pleural effusions were studied by thoracentesis. Pleural effusions with a concentration of triglycerides higher than 110 mg/dL, a pleural fluid to serum triglyceride ratio higher than 1, and a pleural fluid to serum cholesterol ratio lower than 1 were considered chylothorax. RESULTS: Twenty-four patients had pleural effusions that complied with all three aforementioned biochemical conditions. Five of these 24 patients (20%), were found to have liver cirrhosis as the main cause of chylothorax and in 3 of them, an abdominal source of the effusion could be demonstrated by intraperitoneal injection of a radioisotope (99mTc-sulfur colloid). The cirrhotic chylous effusions had significantly lower (p<0.005) protein (median, 1.7; range, 1.4 to 2.7 g/dL), lactate dehydrogenase (LDH) (median, 96; range, 77 to 138 IU/L), and cholesterol (median, 25; range, 22 to 64 mg/dL) levels than chylous effusions resulting from other causes (protein: median, 4.1; range, 1.7 to 6.8 g/dL; LDH: median, 351; range, 140 to 8,600 IU/L; and cholesterol: median, 87; range, 38 to 160 mg/dL). Cirrhotic chylothorax was always a transudate according to Light's criteria. CONCLUSIONS: Chylothorax is a rare and apparently underappreciated manifestation of cirrhosis resulting from transdiaphragmatic passage of chylous ascites. Its uniform biochemical characteristics can facilitate its separation from chylous effusions of different etiology, therefore avoiding potentially harmful diagnostic and therapeutic procedures.

Adult↗
PubMed1998

Tuberculous pleurisy with or without radiographic evidence of pulmonary disease. Is there any difference?

SETTING: A community teaching hospital in Alicante, Spain. OBJECTIVE: To assess the characteristics of tuberculous pleurisy (TP) in our hospital, and to evaluate the differences between primary and reactivation forms. DESIGN: Between January 1984 and December 1993, all human immunodeficiency virus (HIV)-negative patients with TP were included in the study. From September 1987 onward, patients were prospectively studied. Charts, radiography, pleural fluid findings and diagnostic methods were evaluated. Two groups were distinguished according to chest radiographs: those patients with upper lobe lesions, calcified adenopathy and old pleural thickening were considered reactivation forms. RESULTS: Of the 129 patients (mean age, 31 +/- 18 years), 76% had primary TP and 24% reactivation TP. Differences were found in age (28 +/- 17 vs 40 +/- 18 years, P < 0.01), smoking (43% vs 74%, P < 0.01) and alcohol abuse (23% vs 47%, P < 0.05), weight loss (29% vs 50%, P < 0.05), positive sputum smears and cultures (2% vs 16%, 7% vs 28%, P < 0.01), and number of large effusions (46% vs 26%, P < 0.05), but not in tuberculin reactivity, pleural fluid findings, positive pleural cultures, or presence of pleural granuloma. CONCLUSION: In our setting, TP predominantly affects young adults. Clinical, immunological, and pleural findings are similar to those of patients with classic symptoms of TP. Older age, smoking and alcohol abuse, smaller effusions and sputum yield are differential characteristics of reactivation forms.

Adult↗
PubMed1997

Activation of the 43 kDa inositol polyphosphate 5-phosphatase by 14-3-3zeta.

The 43 kDa inositol polyphosphate 5-phosphatase (5-phosphatase) hydrolyzes and thereby inactivates the second messenger molecules inositol 1,4,5-trisphosphate -Ins(1,4,5)P3- and inositol 1,3,4,5-tetrakisphosphate in a signal terminating reaction. Recent studies have shown that the platelet protein pleckstrin forms a complex with the 43 kDa 5-phosphatase and activates Ins(1,4,5)P3 hydrolysis 2-fold [Auethavekiat, V., Abrams, C. S., & Majerus, P. W. (1997) J. Biol. Chem. 272, 1786-1790]. We now show that another platelet protein, 14-3-3zeta, forms a complex with the 43 kDa 5-phosphatase and thereby activates the hydrolysis of Ins(1,4,5)P3. Both pleckstrin and 14-3-3zeta contain one or more pleckstrin-homology domains, both are present in platelet cytosol, and both dimerize and form complexes with other signalling proteins. Purified platelet pleckstrin and 14-3-3zeta enhanced the rate of the hydrolysis of Ins(1,4,5)P3 by the 43 kDa 5-phosphatase 1.9- and 3.8-fold, respectively, but did not activate the 75 kDa 5-phosphatase. We have demonstrated that the mechanism of 5-phosphatase activation by 14-3-3zeta results from specific complex formation between the 43 kDa 5-phosphatase and 14-3-3zeta. Recombinant 43 kDa 5-phosphatase bound to recombinant glutathione S-transferase (GST)/14-3-3zeta fusion protein, but not GST alone, immobilized on glutathione-Sepharose. A potential 14-3-3 binding motif was located in the 43 kDa, but not the 75 kDa, 5-phosphatase. The motif "363RSESEE" is present in close proximity to the proposed catalytic domain of the 43 kDa 5-phosphatase. A synthetic peptide corresponding to the putative 14-3-3 binding motif demonstrated specific, saturable binding to purified 125I-14-3-3, with a Kd of 92 nM. In addition, platelet cytosolic 5-phosphatase bound to recombinant 14-3-3zeta immobilized on glutathione-Sepharose. Thus, 14-3-3zeta serves in human platelets to activate the 43 kDa 5-phosphatase and may thereby function to prevent generation of Ins(1,4,5)P3 -mediated calcium release in unstimulated platelets.

14-3-3 Proteins↗
PubMed1997

Detection of sugar residues in rabbit embryo teeth with lectin-horseradish peroxidase conjugate: II. A light microscopal study.

The cellular distribution and changes of sugar residues during tooth development in embryos of the rabbit Oryctolagus cuniculus were investigated by using horseradish peroxidase-conjugated lectins (lectin-HRP). The lectins SBA, ECA, and LTA show no binding to any region of the dental cap and bell stages, whereas BS-1 and UEA-1 bind to dental cells at both stages. Appropriate control studies confirmed the specificity of the binding of the lectins. At cap stage, the lectins BS-1 and UEA-1 show moderate binding to the (pre)-ameloblast and (pre)-odontoblast cells. These results suggest that the acetylgalactosamine and alpha-L-fucose residues present in (pre)-ameloblasts and (pre)-odontoblasts, respectively, are common to determined but relatively undifferentiated cells capable of forming matrices of hard tissues. Since the odontoblast and ameloblast express dentin and enamel, respectively, it can be speculated that the abundance of these residues in these cells might be associated with the maintenance of the capacity of the cells to produce such matrices. At the bell stage, the odontoblasts display considerable amounts of alpha-L-fucose, whereas alpha-L-fucose is poorly localized in ameloblasts. However, ameloblasts contain significant quantities of N-acetylgalactosamine, whereas only a diffuse positivity for this carbohydrate is apparent in odontoblasts. The marked changes of the glycosylation pattern of these glycoconjugates might indicate that they play a role during the cell-to-cell interaction and might also be involved in the odontoblastic and ameloblastic functional activity. Such a possibility is entirely speculative until specific in vitro experiments are conducted.

Animals↗
PubMed1997

Protective effect of boldine in experimental colitis.

The cytoprotective and anti-inflammatory effects of boldine in an experimental model of acute colitis are reported. The administration of boldine to animals with colitis induced by the intrarectal administration of acetic acid, was found to protect against colonic damage as expressed by major reductions in the extent of cell death, tissue disorganization, and edema. Boldine also reduced the colonic neutrophil infiltration, as measured by the myeloperoxidase activity, but it did not significantly affect tissue lipoperoxides. Boldine was found to preserve the colonic fluid transport, a function otherwise markedly affected in the tissue of acid-treated animals. Results presented here provide experimental evidence supporting new cytoprotective and anti-inflammatory properties of boldine.

Animals↗