Showing papers by "University of São Paulo published in 1998"
TL;DR: As compared with conventional ventilation, the protective strategy was associated with improved survival at 28 days, a higher rate of weaning from mechanical ventilation, and a lower rate of barotrauma in patients with the acute respiratory distress syndrome.
Abstract: Background In patients with the acute respiratory distress syndrome, massive alveolar collapse and cyclic lung reopening and overdistention during mechanical ventilation may perpetuate alveolar injury. We determined whether a ventilatory strategy designed to minimize such lung injuries could reduce not only pulmonary complications but also mortality at 28 days in patients with the acute respiratory distress syndrome. Methods We randomly assigned 53 patients with early acute respiratory distress syndrome (including 28 described previously), all of whom were receiving identical hemodynamic and general support, to conventional or protective mechanical ventilation. Conventional ventilation was based on the strategy of maintaining the lowest positive end-expiratory pressure (PEEP) for acceptable oxygenation, with a tidal volume of 12 ml per kilogram of body weight and normal arterial carbon dioxide levels (35 to 38 mm Hg). Protective ventilation involved end-expiratory pressures above the lower inflection poin...
3,323 citations
TL;DR: Estimation of the content of total phenolic substances, flavonoids, waxes, ash, volatile substances and dry residue be used as parameters to characterize samples of crude propolis and tinctures.
Abstract: SUMMARYA set of parameters and respective procedures for the establishment of chemical profiles of samples of tinctures and crude propolis is presented. It is proposed that estimations of the content of total phenolic substances, flavonoids, waxes, ash, volatile substances and dry residue be used as parameters to characterize samples of crude propolis. For tinctures, the estimations of total phenolic substances, flavonoids, waxes, specific gravity and ethanol are proposed. Total phenolic substances and flavonoids are measured by spectrophotometric methods, waxes gravimetrically and ethanol by gas chromatography. The accuracy of the spectrophotometric procedures was tested by assaying a mixture with a known composition of phenolic acids and flavonoids. The use of the procedures is exemplified by the analyses of six samples of crude propolis from different localities in Brazil and of tinctures prepared with absolute and 70% aqueous ethanol. The contents of total phenolic substances, flavonoids, waxes and vo...
1,011 citations
TL;DR: The optimized δ-expansion is a nonperturbative approach for field theoretic models which combines the techniques of perturbation theory and the variational principle as mentioned in this paper.
Abstract: The optimized δ-expansion is a nonperturbative approach for field theoretic models which combines the techniques of perturbation theory and the variational principle This technique is discussed in the λφ4 model and then implemented in the Walecka model for the equation of state of nuclear matter The results obtained with the δ expansion are compared with those obtained with the traditional mean field, relativistic Hartree and Hartree-Fock approximations
672 citations
TL;DR: In this paper, a standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented and a correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures.
Abstract: A standard library of theoretical stellar spectra intended for multiple synthetic photometry applications including spectral evolutionary synthesis is presented. The grid includes M dwarf model spectra, hence complementing the first library version established in Paper I (Lejeune et al. 1997). It covers wide ranges of fundamental parameters: : 50 000 K ~ 2000 K, : 5.5 , and : . A correction procedure is also applied to the theoretical spectra in order to provide color-calibrated flux distributions over a large domain of effective temperatures. For this purpose, empirical –color calibrations are constructed between 11500 K and 2000 K, and semi -empirical calibrations for non-solar abundances ( to +1.0) are established. Model colors and bolometric corrections for both the original and the corrected spectra, synthesized in the system, are given for the full range of stellar parameters. We find that the corrected spectra provide a more realistic representation of empirical stellar colors, though the method employed is not completely adapted to the lowest temperature models. In particular the original differential colors of the grid implied by metallicity and/or luminosity changes are not preserved below 2500 K. Limitations of the correction method used are also discussed.
593 citations
TL;DR: A novel EspA‐containing filamentous organelle is described that is present on the bacterial surface during the early stage of A/E lesion formation, forms a physical bridge between the bacterium and the infected eukaryotic cell surface and is required for the translocation of EspB into infected epithelial cells.
Abstract: Enteropathogenic Escherichia coli (EPEC), like many bacterial pathogens, employ a type III secretion system to deliver effector proteins across the bacterial cell In EPEC, four proteins are known to be exported by a type III secretion system—EspA, EspB and EspD required for subversion of host cell signal transduction pathways and a translocated intimin receptor (Tir) protein (formerly Hp90) which is tyrosine‐phosphorylated following transfer to the host cell to become a receptor for intimin‐mediated intimate attachment and ‘attaching and effacing’ (A/E) lesion formation The structural basis for protein translocation has yet to be fully elucidated for any type III secretion system Here, we describe a novel EspA‐containing filamentous organelle that is present on the bacterial surface during the early stage of A/E lesion formation, forms a physical bridge between the bacterium and the infected eukaryotic cell surface and is required for the translocation of EspB into infected epithelial cells
580 citations
TL;DR: An epileptic seizure classification based exclusively on ictal semiology is proposed, and seizures are classified as follows: grand mal, dystonic, and convulsive.
Abstract: We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.
542 citations
TL;DR: An oscillometric detector for capillary electrophoresis has been described in this article, where two 2-mm silver rings separated by 1 mm were painted over the polyimide coating of a fused-silica capillary and used as electrodes for oscillometric measurements.
Abstract: An oscillometric detector for capillary electrophoresis (CE) has been described. Two 2-mm silver rings separated by 1 mm were painted over the polyimide coating of a fused-silica capillary (75-μm i.d. and 360-μm o.d.) and used as electrodes for oscillometric measurements. A function generator was used to apply a sinusoidal signal over one of the electrodes; the other one was connected to a current-to-voltage converter. The rectified signal is proportional to the admittance of the cell, which is a function of the inner solution conductivity in the region of the electrodes. Electropherograms of alkaline and alkaline-earth cations showed good signal-to-noise ratio. For typical electrophoretic conditions, the limit of detection for lithium was 1.5 μM, and there was good linearity (R = 0.998 for eight data points) up to 2 mM. Indirect conductivity detection of quaternary ammonium salts was achieved by using potassium acetate running buffer, showing results similar to those from conventional conductometric dete...
474 citations
TL;DR: In this article, different formulations for the overdispersion mechanism can lead to different variance functions which can be placed within a general family of estimation methods, including maximum likelihood, moment methods, extended quasi-likelihood, pseudo-like likelihood and non-parametric maximum likelihood.
463 citations
TL;DR: It is argued that the Neanderthal and modern lineages share a common ancestor in an African population between 350,000 and 250,000 years ago rather than in the earlier Middle Pleistocene; this ancestral population, which developed mode 3 technology (Levallois/Middle Stone Age), dispersed across Africa and western Eurasia in a warmer period prior to independent evolution towards Neanderthals and modern humans in stage 6.
Abstract: The origins of modern humans have been the central debate in palaeoanthropology during the last decade We examine the problem in the context of the history of anthropology, the accumulating evidence for a recent African origin, and evolutionary mechanisms Using a historical perspective, we show that the current controversy is a continuation of older conflicts and as such relates to questions of both origins and diversity However, a better fossil sample, improved dates, and genetic data have introduced new perspectives, and we argue that evolutionary geography, which uses spatial distributions of populations as the basis for integrating contingent, adaptive, and demo- graphic aspects of microevolutionary change, provides an appropriate theoreti- cal framework Evolutionary geography is used to explore two events: the evolution of the Neanderthal lineage and the relationship between an ancestral bottleneck with the evolution of anatomically modern humans and their diversity We argue that the Neanderthal and modern lineages share a common ancestor in an African population between 350,000 and 250,000 years ago rather than in the earlier Middle Pleistocene; this ancestral population, which developed mode 3 technology (Levallois/Middle Stone Age), dispersed across Africa and western Eurasia in a warmer period prior to independent evolution towards Neanderthals and modern humans in stage 6 Both lineages would thus share a common large-brained ancestry, a technology, and a history of dispersal They differ in the conditions under which they subsequently evolved and their ultimate evolutionary fate Both lineages illustrate the repeated interactions of the glacial cycles, the role of cold-arid periods in producing fragmentation of populations, bottlenecks, and isolation, and the role of warmer periods in producing trans-African dispersals Yrbk Phys Anthropol 41:137-176, 1998 r 1998 Wiley-Liss, Inc
436 citations
TL;DR: In this paper, the authors developed an empirical potential for silicon which represents a considerable improvement over existing models in describing local bonding for bulk defects and disordered phases, and applied it to the relaxation of point defects, core properties of partial dislocations and the structure of disordered phase, none of which are included in the fitting procedure.
Abstract: We develop an empirical potential for silicon which represents a considerable improvement over existing models in describing local bonding for bulk defects and disordered phases. The model consists of two- and three-body interactions with theoretically motivated functional forms that capture chemical and physical trends as explained in a companion paper. The numerical parameters in the functional form are obtained by fitting to a set of ab initio results from quantum-mechanical calculations based on density-functional theory in the local-density approximation, which include various bulk phases and defect structures. We test the potential by applying it to the relaxation of point defects, core properties of partial dislocations and the structure of disordered phases, none of which are included in the fitting procedure. For dislocations, our model makes predictions in excellent agreement with ab initio and tight-binding calculations. It is the only potential known to describe both the 30°- and 90°-partial dislocations in the glide set$111%. The structural and thermodynamic properties of the liquid and amorphous phases are also in good agreement with experimental and ab initio results. Our potential is capable of simulating a quench directly from the liquid to the amorphous phase, and the resulting amorphous structure is more realistic than with existing empirical preparation methods. These advances in transferability come with no extra computational cost, since force evaluation with our model is faster than with the popular potential of Stillinger-Weber, thus allowing reliable atomistic simulations of very large atomic systems. @S0163-1829~98!04026-0#
406 citations
TL;DR: The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vivo systems.
Abstract: Spirulina maxima, which is used as a food additive, is a microalga rich in protein and other essential nutrients. Spirulina contains phenolic acids, tocopherols and beta-carotene which are known to exhibit antioxidant properties. The aim of the present study was to evaluate the antioxidant capacity of a Spirulina extract. The antioxidant activity of a methanolic extract of Spirulina was determined in vitro and in vivo. The in vitro antioxidant capacity was tested on a brain homogenate incubated with and without the extract at 37 degrees C. The IC50 (concentration which causes a 50% reduction of oxidation) of the extract in this system was 0.18 mg/ml. The in vivo antioxidant capacity was evaluated in plasma and liver of animals receiving a daily dose of 5 mg for 2 and 7 weeks. Plasma antioxidant capacity was measured in brain homogenate incubated for 1 h at 37 degrees C. The production of oxidized compounds in liver after 2 h of incubation at 37 degrees C was measured in terms of thiobarbituric acid reactant substances (TBARS) in control and experimental groups. Upon treatment, the antioxidant capacity of plasma was 71% for the experimental group and 54% for the control group. Data from liver spontaneous peroxidation studies were not significantly different between groups. The amounts of phenolic acids, alpha-tocopherol and beta-carotene were determined in Spirulina extracts. The results obtained indicate that Spirulina provides some antioxidant protection for both in vitro and in vivo systems.
TL;DR: The smoke, clouds, and radiation-Brazil (SCAR-B) field project as mentioned in this paper has been used to study biomass burning, emphasizing measurements of surface biomass, fires, smoke aerosol and trace gases, clouds and radiation.
Abstract: The Smoke, Clouds, and Radiation-Brazil (SCAR-B) field project took place in the Brazilian Amazon and cerrado regions in August-September 1995 as a collaboration between Brazilian and American scientists. SCAR-B, a comprehensive experiment to study biomass burning, emphasized measurements of surface biomass, fires, smoke aerosol and trace gases, clouds, and radiation. their climatic effects, and remote sensing from aircraft and satellites. It included aircraft and ground-based in situ measurements of smoke emission factors and the compositions, sizes, and optical properties of the smoke particles; studies of the formation of ozone; the transport and evolution of smoke; and smoke interactions with water vapor and clouds. This overview paper introduces SCAR-B and summarizes some of the main results obtained so far. (1) Fires: measurements of the size distribution of fires, using the 50 m resolution MODIS Airborne Simulator, show that most of the fires are small (e.g. 0.005 square km), but the satellite sensors (e.g., AVHRR and MODIS with I km resolution) can detect fires in Brazil which are responsible for 60-85% of the burned biomass: (2) Aerosol: smoke particles emitted from fires increase their radius by as much as 60%, during their first three days in the atmosphere due to condensation and coagulation, reaching a mass median radius of 0.13-0.17 microns: (3) Radiative forcing: estimates of the globally averaged direct radiative forcing due to smoke worldwide, based on the properties of smoke measured in SCAR-B (-O.l to -0.3 W m(exp -2)), are smaller than previously modeled due to a lower single-scattering albedo (0.8 to 0.9), smaller scattering efficiency (3 square meters g(exp -2) at 550 nm), and low humidification factor; and (4) Effect on clouds: a good relationship was found between cloud condensation nuclei and smoke volume concentrations, thus an increase in the smoke emission is expected to affect cloud properties. In SCAR-B, new techniques were developed for deriving the absorption and refractive index of smoke from ground-based remote sensing. Future spaceborne radiometers (e.g., MODIS on the Earth Observing System), simulated on aircraft, proved to be very useful for monitoring smoke properties, surface properties, and the impacts of smoke on radiation and climate.
TL;DR: In this paper, an elevated T-maze with three elevated arms, one enclosed and two open, was used to evaluate the ability of rats to escape from an open arm.
TL;DR: By using PCR primers designed on the basis of the intimin-encoding eae gene sequences of serotypes O127:H6, O114:H2, and O86:H34 EPEC and serotype O157:H7 EHEC, the different intimin types were designated α, β, δ, and γ, respectively.
Abstract: Intimins are outer membrane proteins expressed by enteric bacterial pathogens capable of inducing intestinal attachment-and-effacement lesions. A eukaryotic cell-binding domain is located within a 280-amino-acid (Int280) carboxy terminus of intimin polypeptides. Polyclonal antiserum was raised against Int280 from enteropathogenic Escherichia coli (EPEC) serotypes O127:H6 and O114:H2 (anti-Int280-H6 and anti-Int280-H2, respectively), and Western blot analysis was used to explore the immunological relationship between the intimin polypeptides expressed by different clinical EPEC and enterohemorrhagic E. coli (EHEC) isolates, a rabbit diarrheagenic E. coli strain (RDEC-1), and Citrobacter rodentium. Anti-Int280-H6 serum reacted strongly with some EPEC serotypes, whereas anti-Int280-H2 serum reacted strongly with strains belonging to different EPEC and EHEC serotypes, RDEC-1, and C. rodentium. These observations were confirmed by using purified Int280 in an enzyme-linked immunosorbent assay and by immunogold and immunofluorescence labelling of whole bacterial cells. Some bacterial strains were recognized poorly by either antiserum (e.g., EPEC O86:H34 and EHEC O157:H7). By using PCR primers designed on the basis of the intimin-encoding eae gene sequences of serotype O127:H6, O114:H2, and O86:H34 EPEC and serotype O157:H7 EHEC, we could distinguish between different eae gene derivatives. Accordingly, the different intimin types were designated alpha, beta, delta, and gamma, respectively.
TL;DR: In this article, the authors evaluated the impact of combined radiotherapy and chemotherapy on the treatment of potentially resectable low rectal cancer using the following end points: 1) toxicity of this combined modality regimen; 2) clinical and pathologic response rate and local control; 3) downstaging of the tumor and its influence on the number of sphincter-saving operations; 4) disease-free interval, patterns of relapse, and overall survival.
Abstract: INTRODUCTION: The aim of this study was to evaluate the impact of combined radiotherapy and chemotherapy (leucovorin and 5-fluorouracil) on the treatment of potentially resectable low rectal cancer using the following end points: 1) toxicity of this combined modality regimen; 2) clinical and pathologic response rate and local control; 3) downstaging of the tumor and its influence on the number of sphincter-saving operations; 4) disease-free interval, patterns of relapse, and overall survival. METHODS: From 1991 to 1996, 118 patients with potentially resectable cases of histologically proven adenocarcinoma and no distant metastases were enrolled into this protocol. All patients were evaluated by clinical and proctologic examination, abdominal computed tomography, transrectal ultrasound, and chest radiography. Therapy consisted of 5,040 cGy (6 weeks) and concurrent leucovorin (20/mg/m2/day) with bolus doses of 5-fluorouracil administered intravenously at 425 mg/m2/day for three consecutive days on the first and last three days of radiation therapy. After two months, all patients underwent repeat evaluation and biopsy of any suspected residual lesions or scar tissue. RESULTS: Median follow-up was 36 months. Toxicity of chemotherapy regimen was minimum. Thirty-six patients (30.5 percent) were classified as being complete responders. In six of these patients, complete response was confirmed by the absence of tumor in the surgical specimens (3 abdominoperineal resections and 3 proctosigmoidectomies with coloanal anastomosis). In the remaining 30 patients, confirmation of a complete response was made by the absence of symptoms, negative findings on physical examination, and biopsy, transrectal ultrasound, and pelvic computed tomographic test results during follow-up. Eighty-two patients (69.4 percent) were considered incomplete responders. Residual lesions had already been identified during the first examination in 74 patients. In the other eight patients, residual tumor was only identified after 3 to 14 months. All patients underwent surgical treatment, except one patient who refused surgery. Eighty-seven patients underwent 90 surgical procedures: local excision, 9; coloanal anastomosis, 36; abdominoperineal resection, 4; Hartmann's procedure, 1. Isolated local recurrences occurred in five patients (4.3 percent) and combined local and distant failure in eight patients (6.7 percent). Ninety patients are alive and disease-free at a median follow-up of 36 months. CONCLUSIONS: Combined up-front chemoradiotherapy was associated with tolerable and acceptable side effects. A significant number of patients had complete disappearance of their tumors (30.5 percent) within a median follow-up of 36 months. This regimen spared 26.2 percent of patients from surgical treatment and allowed sphincter-saving management in 38.1 percent of patients who may have required abdominoperineal resection. Preliminary results of this trial suggests a reduction in the number of local recurrences and reinforces the concept that infiltrative low rectal cancer may be initially treated by chemoradiotherapy.
TL;DR: The efficacy and safety of these two approaches to treat 10 consecutive patients with VT and Chagas’ disease are reported, including epicardial mapping and endocardial radiofrequency catheter ablation.
Abstract: Nonsurgical Epicardial Ablation. Introduction: An epicardial site of origin of ventricular tachycardia (VT) may explain unsuccessful endocardial radiofrequency (RF) catheter ablation. A new technique to map the epicardial surface of the heart through pericardial puncture was presented recently and opened the possibility of using epicardial mapping to guide endocardial ablation or epicardial catheter ablation. We report the efficacy and safety of these two approaches to treat 10 consecutive patients with VT and Chagas’ disease.
Methods and Results: Epicardial mapping was carried out with a regular steerable catheter introduced into the pericardial space. An epicardial circuit was found in 14 of 18 mapable VTs induced in 10 patients. Epicardial mapping was used to guide endocardial ablation in 4 patients and epicardial ablation in 6. The epicardial earliest activation site occurred 107 ± 60 msec earlier than the onset of the QRS complex. At the epicardial site used to guide endocardial ablation, earliest activation occurred 75 ± 55 msec before the QRS complex. Epicardial mid-diastolic potentials and/or continuous electrical activity were seen in 7 patients. After 4.8 ± 2.9 seconds of epicardial RF applications, VT was rendered noninducible. Hemopericardium requiring drainage occurred in 1 patient; 3 others developed pericardial friction without hemopericardium. Patients remain asymptomatic 5 to 9 months after the procedure. Interruption during endocardial pulses occurred after 20.2 ± 14 seconds (P = 0.004), hut VT was always reinducible and the patients experienced a poor outcome.
Conclusion: Epicardial mapping does not enhance the effectiveness of endocardial pulses of RF. Epicardial applications of RF energy can safely and effectively treat patients with VT and Chagas’ disease.
TL;DR: The progressive accumulation of interstitial collagen fibers in left ventricular hypertrophy, in parallel to an increase in heart weight, can be expected to contribute to a spectrum of ventricular dysfunction involving either the diastolic or systolic phase of the cardiac cycle, or both, that is associated with the greater than normal arrhythmogenic risk for a hypertensive heart.
Abstract: Objective To investigate pathologic fibrosis and connective tissue matrix in left ventricular hypertrophy due to chronic arterial hypertension in humans. Design and methods Seventeen human hearts were studied. Group 1 consisted of control hearts (four hearts, weighing 280 ± 40 g each), from subjects who had had no evidence of heart disease and for whom the diagnoses of death were noncardiac. Groups 2 (five hearts, weighing 440 ± 50 g each), 3 (five hearts, weighing 560 ± 50 g each), and 4 (three hearts, weighing 680 ± 60 g each) consisted of hearts from subjects who had had a history of systemic hypertension. All hearts had no valvular deformities and no evidence of ischemic disease at the postmortem examination. A cell-maceration method was employed to evaluate the myocardial connective matrix after removal of the nonfibrous elements of myocardial tissue, leaving behind a noncollapsed matrix, thus allowing a better three-dimensional view. Myocardial tissue was also processed for conventional light microscopic and morphometric studies. Results The minor transverse diameter of myocytes from hearts in groups 1-4 hearts were 13.7 ± 7.8, 23.7 ± 3.4, 26.6 ± 3.7, and 32.8 ± 5.8 μm, respectively. The volume fraction of fibrosis of the controls was 6.5%, whereas the volume fractions in hypertensive hearts increased progressively according to heart weight: 15.4, 22.9, and 31.1% for hearts in groups 2, 3, and 4, respectively. The most striking feature was the diffuse marked increase in amount of pericellular collagen weave fibers (endomysial matrix), parallel to the increase of heart weight The hypertrophied myocytes were encased in a dense weave of collagen fibrils continuous with those of adjacent myocytes. The muscle fibers in hypertrophied hearts were markedly larger than normal, although this was extremely variable from an area to another. Besides, a diffuse increase in the number of thick collagen fibers constituting broad bands and sheets of collagen surrounding disorganized muscle bundles (perimysial matrix) was observed. Scattered dense scar-like foci, apparently replacing areas of myocyte loss, could be seen, mainly on the periphery of muscle bundles. This latter finding was more commonly observed among hypertrophied hearts from group 3 and, mainly, among hypertrophied hearts of group 4. Importantly, a progressive disarray of the connective tissue skeleton of the myocardium could be seen in parallel to the progressive increase of cardiac hypertrophy. Conclusions The progressive accumulation of interstitial collagen fibers in left ventricular hypertrophy, in parallel to an increase in heart weight, can be expected to contribute to a spectrum of ventricular dysfunction involving either the diastolic or systolic phase of the cardiac cycle, or both, that is associated with the greater than normal arrhythmogenic risk for a hypertensive heart. Moreover, the methodology used is useful for studying the spatial organization of the collagen fibrils of the myocardium under normal and pathologic conditions.
TL;DR: In this paper, the stable isotope 13 C is used to estimate SOM turnover rates and the sensitivity of different models and different model parameters, using a chronosequence of forest and pastures of different ages from the Brazilian Amazon.
TL;DR: These findings highlight the importance of common respiratory viruses, particularly HRV and RSV, in predisposing to and causing AOM in young children.
Abstract: Objective. To determine the frequencies of human rhinovirus (HRV), respiratory syncytial virus (RSV), and coronavirus (HCV) infection in children with acute otitis media (AOM). Methods. Middle ear fluids (MEF) collected by tympanocentesis and nasopharyngeal aspirates (NPA) at the time of the AOM diagnosis were examined by reverse transcriptase polymerase chain reaction for HRV, RSV, and HCV RNA. Patients. Ninety-two children aged 3 months to 7 years during a 1-year period. Results. Virus RNA was detected in a total of 69 children (75%) and in 44 MEF samples (48%) and 57 NPA samples (62%) at the time of AOM diagnosis. HRV RNA was detected in both MEF and NPA in 18 (20%), in MEF alone in 4 (4%), and in NPA alone in 10 (11%). RSV was detected in both MEF and NPA in 12 (13%), in MEF alone in 5 (5%), and in NPA alone in 9 (10%). HCV RNA was detected in both MEF and NPA in 5 (5%), in MEF alone in 2 (2%), and in NPA alone in 9 (10%). Dual viral infections were detected in 5% of children. HRV and RSV were detected simultaneously in 2 MEF samples and in 2 NPA samples; RSV and HCV were detected in 1 NPA sample. Bacterial pathogens were detected in 56 (62%) MEF from 91 children. Viral RNA was detected in 20 (57%) MEF of 35 bacteria-negative and in 25 (45%) of 56 bacteria-positive MEF samples. No important differences in the risk of treatment failure, relapse, or occurrence of late secretory otitis media were noted between children with virus-positive and virus-negative MEF aspirates. Conclusion. These findings highlight the importance of common respiratory viruses, particularly HRV and RSV, in predisposing to and causing AOM in young children.
TL;DR: This review is centered on the cardiovascular and particularly the renal functional and structural consequences of chronic pharmacologic NO inhibition by l-arginine analogues, and devoted special attention to the mechanisms of hypertension and organ injury that occur under these circumstances.
Abstract: The discovery in 1987 that endothelium-derived nitric oxide (NO) mediates the vasodilatory effect of certain endothelium-dependent agonists1 2 inaugurated the current huge field of NO biology. It is now recognized that NO plays essential roles in many diverse physiological processes and in some pathophysiologic events. Development of these concepts has been based largely on evidence obtained by limiting NO biosynthesis. This review is centered on the cardiovascular and particularly the renal functional and structural consequences of chronic pharmacologic NO inhibition by l-arginine analogues. We devoted special attention to the mechanisms of hypertension and organ injury that occur under these circumstances, while appreciating the inherent limitations surrounding interpretation of this data.
NO is made by the enzymatic action of several widely distributed NO synthases (NOS). In the presence of the substrates l-arginine and oxygen, as well as a number of essential cofactors, NO is produced in response to appropriate stimuli. The constitutively expressed NOS play a major role in the physiological control of vascular tone and kidney function.3 4 Vascular endothelial NOS (eNOS) and brain-type NOS (bNOS) are widely distributed throughout the kidney5 as well as the cardiovascular system and in strategic locations in the peripheral and central nervous system (CNS).6 7
Both eNOS and particularly bNOS are abundant in the kidney, glomeruli, and vasculature as well as in most segments of the tubule,3 5 and NOS activity in medulla is considerably greater than in cortex.8 NO generated within the kidney controls the glomerular filtration rate (GFR), total renal and medullary blood flow, pressure natriuresis, epithelial sodium transport, and production of various vasoactive factors including renin.3 4 5 eNOS is distributed throughout most parts of the arterial and venous circulation, although there is considerable heterogeneity in the extent to which NO controls …
TL;DR: In this paper, current meter observations from an array of three subsurface moorings located on the Brazil continental slope near 4°N are used to describe the annual cycle and low-frequency variability of the North Brazil Current (NBC).
Abstract: Current meter observations from an array of three subsurface moorings located on the Brazil continental slope near 4°N are used to describe the annual cycle and low-frequency variability of the North Brazil Current (NBC). The moored array was deployed from September 1989 to January 1991, with further extension of the shallowest mooring, located over the 500-m isobath near the axis of the NBC, through September 1991. Moored current measurements were also obtained over the adjacent shelf for a limited time between February and May 1990. The NBC has a large annual cycle at this latitude, ranging from a maximum transport of 36 Sv (Sv ≡ 106 m3 s−1) in July–August to a minimum of 13 Sv in April–May, with an annual mean transport of approximately 26 Sv. The mean transport is dominated by flow in the upper 150 m, and the seasonal cycle is contained almost entirely in the top 300 m. Transport over the continental shelf is 3–5 Sv and appears to be fairly constant throughout the year, based on the available...
TL;DR: The results suggest that air pollution in São Paulo may promote adverse health effects on fetuses, and some evidence of fetal exposure to air pollution was obtained by disclosing a significant association between the levels of carboxyhemoglobin of blood sampled from the umbilical cord and ambient CO levels in children delivered by nonsmoking pregnant women in the period from May to July 1995.
Abstract: The associations among daily counts of intrauterine mortality and pollutant concentrations (NO2, SO2, CO, O3, and particulate matter (3/4)10 microm) were investigated for the period ranging from Ja...
TL;DR: This paper identifies a number of possibly desirable properties of a shape similarity method, and determines the extent to which these properties can be captured by approaches that compare local properties of the contours of the shapes, through elastic matching.
TL;DR: It is suggested that the uterine contractions induced by misoprostol cause vascular disruption in the fetus, including brain-stem ischaemia, in children born with congenital abnormalities.
01 Jan 1998
TL;DR: In this paper, an inverse semigroup S(G) associated to a group G is constructed, in a canonical way, and the actions of S (G) are shown to be in one-to-one correspondence with the partial actions of G, both in the case of actions on a set, and that of actions as operators on a Hilbert space.
Abstract: Given a group G, we construct, in a canonical way, an inverse semigroup S(G) associated to G. The actions of S(G) are shown to be in one-to-one correspondence with the partial actions of G, both in the case of actions on a set, and that of actions as operators on a Hilbert space. In other words, G and S(G) have the same representation theory. We show that S(G) governs the subsemigroup of all closed linear subspaces of a G-graded C*-algebra, generated by the grading subspaces. In the special case of finite groups, the maximum number of such subspaces is computed. A "partial" version of the group C*-algebra of a discrete group is introduced. While the usual group C*-algebra of finite commutative groups forgets everything but the order of the group, we show that the partial group C*-algebra of the two commutative groups of order four, namely Z/4Z and Z/2Z ED Z/2Z, are not isomorphic.
TL;DR: It is shown that expression of Bcr–Abl in HL-60 cells rendered them extremely resistant to apoptosis induced by a wide variety of agents and the anti-apoptotic effect was found to be independent of the phase of the cell cycle.
Abstract: Bcr - Abl is the molecule responsible for both the transformation phenotype and the resistance to chemotherapeutic drugs found in chronic myelogenous leukemia (CML) cells. Wild-type HL-60, a transformed pro-myelocytic cell line, is very susceptible to apoptosis-inducing agents. We show here that expression of Bcr - Abl in HL-60 cells rendered them extremely resistant to apoptosis induced by a wide variety of agents. The anti-apoptotic effect of Bcr - Abl was found to be independent of the phase of the cell cycle. Treatment with antisense oligonucleotides directed to bcr decreased the expression of the ectopic bcr - abl and restored susceptibility to apoptosis. Double mutations affecting the autophosphorylation site and the phosphotyrosine-binding motif (FLVRES) have been previously shown to impair the transforming activity of Bcr - Abl in fibroblasts and hematopoietic cells, however HL-60 cells expressing this double mutant molecule exhibited the same level of resistance to apoptosis as those expressing the wild-type Bcr - Abl. Interestingly, wild type and mutant Bcr - Abl induced in HL-60 cells a dramatic down regulation of Bcl-2 and increased the levels of Bcl-xL. The level of Bax did not change in response to the presence of Bcr - Abl. Antisense oligonucleotides targeted to bcl-x downregulated the expression of Bcl-x, and increased the susceptibility of HL-60. Bcr - Abl cells to staurosporine. Importantly, HL-60 cells overexpressing Bcl-xL showed higher expression of Bcl-xL but lower resistance to apoptosis when compared to HL-60. Bcr - Abl cells. The results described here show that Bcr - Abl is a powerful mammalian anti-apoptotic molecule and can act independently of Bcl-2. Bcl-xL, however, seems to participate in part in Bcr - Abl-mediated resistance to apoptosis in HL-60 cells.
TL;DR: A model in which the influence of endogenous RA on heart development depends upon localized presentation of the ligand, with only limited diffusion from the source of its synthesis is supported.
TL;DR: In this paper, a spin-probe method is described that can detect changes in the relative aggregation numbers in SDS micelles with a precision of about one molecule, based on the fact that the 14N hyperfine coupling constant is sensitive to the average fraction of the volume occupied by water in the region of the nitroxide moiety that is located on average near the micelle surface.
Abstract: A spin-probe method is described that can detect changes in the relative aggregation numbers in SDS micelles with a precision of about one molecule. The method is based on the fact that the 14N hyperfine coupling constant is sensitive to the average fraction of the volume occupied by water in the region of the nitroxide moiety that is located on average near the micelle surface. Defining A0(NA) to be the 14N hyperfine coupling constant at an aggregation number NA, we find A0(NA) = A0(0) + (∂A0/∂NA)NA, where NA is controlled by varying either the SDS or the NaCl concentrations. For the spin probe 5-doxylstearic acid ester(5DSE), by combination of the results of experiments in which the SDS and/or the NaCl concentrations were varied, linear least-squares fits gave A0(0) = (15.498 ± 0.009) G and ∂A0/∂NA = − 3.99 ± 0.02 mG/molecule (constant). A0(NA) depends only on the aggregation number despite the fact that a given value of NA may be prepared by choosing different combinations of NaCl and SDS concentration...
TL;DR: In this paper, the authors compare the electrochemical behavior and electroanalytical performance of thin-film carbon sensors fabricated with four different commercial carbon inks and show that the resulting sensors exhibit a wide range of electrochemical reactivities for benchmark redox systems and different background currents.
TL;DR: A nonenzymatic, nontoxic procedure for efficient DNA extraction from fresh and cryopreserved clotted blood is optimized.
Abstract: In the routine clinical laboratory, large amounts of uncoagulated blood are collected and the blood clot usually is discarded. In molecular biology, cells from EDTA-anticoagulated or acid-citrate-dextrose-anticoagulated peripheral blood are used as sources of DNA (1)(2)(3). After leukocyte isolation, most procedures utilize enzymatic cell digestion, followed by extraction with hazardous organic solvents (phenol-chloroform) and precipitation with ethanol (4)(5). To minimize the volume of blood collected for laboratory tests, several authors have developed methodologies to isolate DNA from blood clots (4)(5)(6)(7)(8). However, the techniques may be difficult or impractical and may require slicing of the clot with scalpels or other sharp instrument, exposing laboratory personnel directly to contaminated blood (4)(7). Other techniques are time-consuming, using many chaotropic reagents, enzymes, RNA-removal steps, or large volumes of samples and reagents not suitable in the clinical laboratory (4)(5)(6)(7)(8).
We have optimized a nonenzymatic, nontoxic procedure for efficient DNA extraction from fresh and cryopreserved clotted blood.
Blood samples were obtained from 24 unrelated individuals who had given informed consent. We compared 10 paired samples of EDTA-anticoagulated blood and fresh blood clot …