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Biomedical subjects

S Romero

Publications and source records attributed to S Romero.

At least 19 recordsLinked to original sources
PubMed2000

The inositol polyphosphate 5-phosphatases and the apurinic/apyrimidinic base excision repair endonucleases share a common mechanism for catalysis.

Inositol polyphosphate 5-phosphatases (5-phosphatase) hydrolyze the 5-position phosphate from the inositol ring of phosphatidylinositol-derived signaling molecules; however, the mechanism of catalysis is only partially characterized. These enzymes play critical roles in regulating cell growth, apoptosis, intracellular calcium oscillations, and post-synaptic vesicular trafficking. The UCLA fold recognition server (threader) predicted that the conserved 300-amino acid catalytic domain, common to all 5-phosphatases, adopts the fold of the apurinic/apyrimidinic (AP) base excision repair endonucleases. PSI-BLAST searches of GENPEPT, using the amino acid sequence of AP endonuclease exonuclease III, identified all members of the 5-phosphatase family with highly significant scores. A sequence alignment between exonuclease III and all known 5-phosphatases revealed six highly conserved motifs containing residues that corresponded to the catalytic residues in the AP endonucleases. Mutation of each of these residues to alanine in the mammalian 43-kDa, or yeast Inp52p 5-phosphatase, resulted in complete loss of enzyme activity. We predict the 5-phosphatase enzymes share a similar mechanism of catalysis to the AP endonucleases, consistent with other common functional similarities such as an absolute requirement for magnesium for activity. Based on this analysis, functional roles have been assigned to conserved residues in all 5-phosphatase enzymes.

Amino Acid Sequence↗
PubMed2000

[Compliance with inhalation treatment of patients with chronic obstructive pulmonary disease].

OBJECTIVES: To evaluate patient compliance with inhaled medication therapy in chronic obstructive pulmonary disease (COPD), to identify determining factors and to propose corrective measures to improve compliance. METHODS: This was an open, observational, cross-sectional, non-comparative, single-measurement, non-random study. The inhalers were the Serevent Accuhaler, the Serevent Inhalador and the Flixotide Inhaler. Compliance was measured in four ways: a) difference in weight at the beginning and end of the study for all devices; b) dose counter reading for the Accuhaler; c) information from patient diaries (by days and by applications); and d) information from patient interviews using the Morinsky-Green Test. Compliance was rated as follows: poor: < 50%, fair 51%-79%, good 80%-119%, or "hypercompliant" > 120%. RESULTS: Seventy-two patients (mean age 65 years) were enrolled. Compliance measured by weight was good in 77.1%, fair in 11.5%, poor in 1.4% and hypercompliant in 10%. Compliance was good for the Accuhaler according to both weight (75%) and counted doses (83.3%). According to patient diaries, compliance was good when assessed by applications (98.8%) and by days (98.3%). According to the Morinksky-Green test, compliance was good for 87.9%. CONCLUSIONS: Compliance was good as assessed by the methods used in this study. Patients who live in families, who enjoy a high socioeconomic level, have simple therapeutic regimens and have a good understanding of their disease and inhaler tend to have good compliance. Careful patient follow-up and good patient-physician communication has improved compliance. However, follow-up studies are needed to check these results.

Administration, Inhalation↗
PubMed2000

Nontraumatic chylothorax.

Nontraumatic chylothorax is an uncommon condition of thoracic or abdominal origin caused by multiple disorders, of which malignancy is by far the most frequent one. Because gross appearance of pleural fluid is frequently misleading, pleural fluid and serum lipid analysis is required for its diagnosis. In addition to the presence of chylomicrons, chylothoraces are usually characterized by all three of the following: (1) a triglyceride level of more than 110 mg/dL; (2) a ratio of pleural fluid to the serum triglyceride level of more than 1.0; and (3) a ratio of the pleural fluid to serum cholesterol level of less than 1.0. In patients with lymphoma-related chylothorax refractory to chemotherapy and radiation therapy, medical thoracoscopic talc pleurodesis has an acceptable complication rate and a 100% success rate in the prevention of recurrences. Pleuroperitoneal shunting is considered a safe and effective treatment in the management of persistent chylothorax in children in the absence of chylous ascites.

Chylothorax↗
PubMed2000

Sonicated diagnostic immunoblot for bartonellosis.

Two simple Bartonella bacilliformis immunoblot preparation methods were developed. Antigen was prepared by two different methods: sonication of whole organisms or glycine extraction. Both methods were then tested for sensitivity and specificity. Well-defined control sera were utilized in the development of these diagnostic immunoblots, and possible cross-reactions were thoroughly examined. Sera investigated for cross-reaction with these diagnostic antigens were drawn from patients with brucellosis, chlamydiosis, Q fever, and cat scratch disease, all of whom were from regions where bartonellosis is not endemic. While both immunoblots yielded reasonable sensitivity and high specificity, we recommend the use of the sonicated immunoblot, which has a higher sensitivity when used to detect acute disease and produces fewer cross-reactions. The sonicated immunoblot reported here is 94% sensitive to chronic bartonellosis and 70% sensitive to acute bartonellosis. In a healthy group, it is 100% specific. This immunoblot preparation requires a simple sonication protocol for the harvesting of B. bacilliformis antigens and is well suited for use in regions of endemicity.

Bartonella↗
PubMed2000

Effects of androgen treatment on expression of macrophage Fcgamma receptors.

Macrophage Fcgamma receptors (FcgammaRs) play an important role in the host defense against infection and in the pathophysiology of immune cytopenias. Modulation of macrophage FcgammaR expression is a potential therapeutic approach to immune disorders. Glucocorticoids and progesterones decrease macrophage FcgammaR expression. We assessed the effect of treatment with androgens and antiandrogens on the expression of macrophage FcgammaRs using an experimental guinea pig model. Four androgens (testosterone, dihydrotestosterone, mesterolone, and danazol) and five antiandrogens (flutamide, nilutamide, cyproterone acetate, spironolactone, and finasteride) were studied. Following in vivo treatment of guinea pigs, we determined the clearance of immunoglobulin G (IgG)-sensitized erythrocytes in vivo, the binding of IgG-sensitized erythrocytes by isolated splenic macrophages, and splenic macrophage FcgammaR cell surface expression. All of the androgens impaired the clearance of IgG-sensitized erythrocytes by decreasing splenic macrophage FcgammaR expression. Dihydrotestosterone and mesterolone were more effective than testosterone or dihydrotestosterone. Flow cytometry and fluorescence microscopy with monoclonal antibodies demonstrated that the androgens decreased the cell surface expression of FcgammaR1,2 more than that of FcgammaR2. Antiandrogens did not significantly alter macrophage FcgammaR expression. Nevertheless, antiandrogens counteracted the effects of androgens on macrophage FcgammaR expression. These data indicate that androgens impair the clearance of IgG-coated cells by decreasing splenic macrophage FcgammaR expression. Thus, androgens other than danazol are candidate drugs for the treatment of immune disorders.

Androgens↗
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↗