Latex Fractionation by Sedimentation and Colloidal Crystallization: The Case of Poly(styrene-co-acrylamide).

Poly(styrene-co-acrylamide) (PS-AAM) latex was prepared, fractionated by sedimentation under gravity, and characterized by PCS, infrared spectra, secondary and backscattered electron imaging in the scanning electron microscope, and electron spectroscopy imaging in an analytical transmission electron microscope. Three latex fractions were obtained. The lower fraction was opalescent and its particles were the more uniform, concerning size, chemical composition, and topochemical features.

Pleomorphic xanthoastrocytoma of the cerebellum.

We report a clinicopathologic case of a pure cerebellar pleomorphic xanthoastrocytoma occurring in a 68-year-old male patient. The occurrence of pleomorphic xanthoastrocytoma outside the cerebral hemispheres is exceedingly rare. In the cerebellum only five cases have been reported so far, four of which are composite pleomorphic xanthoastrocytoma-gangliogliomas.

Magnetic resonance imaging of the temporal bone in patients with Ménière's disease.

Ménière's disease (MD) is still controversial in several aspects. The vestibular aqueduct, the osseous channel that carries the endolymphatic duct and sac, has previously been studied by tomography and computed tomography, with shortening and narrowing of this structure observed. These findings are apparently correlated to the development of the endolymphatic hydrops present in MD and related to its episodic symptoms.

Radiation therapy and high-dose tamoxifen in the treatment of patients with diffuse brainstem gliomas: results of a Brazilian cooperative study. Brainstem Glioma Cooperative Group.

Purpose: The efficacy of radiation therapy (RT) combined with tamoxifen (TX) was tested in patients diagnosed with diffuse brainstem gliomas in a multicenter trial.

Patients And Methods: TX was administered orally (maintenance dose: 200 mg/m(2) per day) along with conventional local RT and then continued for 52 additional weeks. Survival, tumoral radiologic response, and toxicity were evaluated.

Standardization of broth microdilution method for Mycobacterium tuberculosis.

Indirect drug susceptibility tests of Mycobacterium tuberculosis was done to investigate the accuracy and feasibility of a broth microdilution method (BMM) for determining minimal inhibitory concentrations of conventional drugs against M. tuberculosis. Test drugs included isoniazid (H), rifampicin (R), ethambutol (E), streptomycin (S) and pyrazinamide (Z).

[Association of Helicobacter pylori and chronic idiopathic urticaria].

Objectives: To analise the etiological association of Hp and Idiopathic Chronic Urticaria (UCI).

Material And Methods: Case control study. Eighteen patients over 18 years with clinical and laboratory evidences of ICU have been studied.

[Primary sclerosing cholangitis in children and adolescents].

Primary sclerosing cholangitis is a disease usually with a poor prognosis with a mean survival of 10-12 years, starting from the time of diagnosis. Among the different populations studied, males predominate in a ratio 2:1 with ages ranging from 20-78 (mean 42 years). This article describes four patients with this syndrome, a child of eight and three adolescents, thirteen and fourteen years old.

Sympathetic nervous system representation in time and frequency domain indices of heart rate variability.

This study evaluated the contributions of sympathetic and parasympathetic modulation to heart rate variability during situations in which vagal and sympathetic tone predominated. In a placebo-controlled, randomized, double blind blockade study, six young healthy male individuals received propranolol (0.2 mg x kg(-1)), atropine (0.

Identification of mycobacteria by thin layer chromatographic analysis of mycolic acids and conventional biochemical method: four years of experience.

Mycolic acids analysis by thin-layer chromatography (TLC) has been employed by several laboratories worldwide as a method for fast identification of mycobacteria. This method was introduced in Brazil by our laboratory in 1992 as a routine identification technique. Up to the present, 861 strains isolated were identified by mycolic acids TLC and by standard biochemical tests; 61% out of these strains came as clinical samples, 4% isolated from frogs and 35% as environmental samples.

The influence of reperitonization on the induction of formation of intraperitoneal adhesions by a polypropylene mesh prosthesis. An experimental study in rats.

The correction of groin hernias has increasingly been performed by transperitoneal videolaparoscopic methods, using a polypropylene mesh. This could lead to an increased incidence of adhesion formation. The incidence of adhesions induced by mesh placement and the influence of reperitonization was observed on 40 male adult Wistar rats.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred.

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion.

MR of parenchymal spinal cord signal change as a sign of active advancement in clinically progressive posttraumatic syringomyelia.

Extensive MR signal change in the craniad spinal cord parenchyma was found to be an ancillary sign of disease advancement in three patients with clinically progressive posttraumatic syringomyelia. This craniad margin of parenchymal spinal cord T2 hyperintensity resolved after cystoperitoneal shunt placement. There was a concomittant reduction or disappearance of the cyst in each instance, a halt in the progression of neurologic deficit, and some reversal of signs and symptoms.

Autosomal recessive deficiency of combined pituitary hormones (except ACTH) in a consanguineous Brazilian kindred.

Familial hypopituitarism represents a clinically and genetically heterogeneous disorder. In a subset of these families, defects in Pit-I, a transcription factor essential for proper pituitary development have been identified as underlying molecular cause. These patients present extreme short stature, GH, PRL and TSH deficiency but intact ACTH, LH and FSH secretion.

MR imaging of intramedullary and intradural-extramedullary spinal cysticercosis.

Objective: The purpose of our study was to retrospectively review the MR imaging findings in a group of patients with clinically proven cysticercosis involving the spinal cord, the spinal subarachnoid space, or both.

Materials And Methods: We retrospectively reviewed images of 16 patients with clinically diagnosed spinal cysticercosis to summarize the imaging characteristics. All patients underwent T1- and T2-weighted sagittal, axial, or both sagittal and axial MR imaging before i.

Prospective study of strongyloidosis in patients with hematologic malignancies.

Immunocompromised individuals infected with Strongyloides stercoralis may develop severe hyperinfection or disseminated disease with high mortality. Patients with hematological malignancies are at risk because of immunodepression produced either by the disease or its treatment. A prospective study was undertaken at the Hospital de Clínicas de Porto Alegre, from July 1994 to July 1995.

MRI of cervical facet dislocation.

The MRI examinations of eight patients with cervical vertebral dislocation demonstrated by conventional radiography were reviewed. All patients had axial and sagittal T1- and T2-weighted imaging on a 1.5-T Unit.

[Sodium diclofenac effect, after interruption of the stercoraceous peritonitis, on the rat colon. Study of mechanical resistance and collagen concentration].

Unlabelled: The objective of the present study was to investigate changes in colon wall in rats with fecal peritonitis (Per) associated with sodium diclofenac (SD) by studying breaking strength and tissue collagen concentration. The rats were divided into the following experimental groups: GROUP 1-SD: 60 animals injected intramuscularly with sodium diclofenac at the dose of 2 mg/kg body weight; GROUP 2-Per: 60 animals injected intraperitoneally with a suspension of human feces. Peritonitis was interrupted after six hours of evolution; GROUP 3-Per+SD: 60 animals injected intraperitoneally with a suspension of human feces and receiving SD according to the schedule used for Groups 1 and 2;

Control Group: 12 animals injected intramuscularly with physiological saline.

Characteristics of tetanic contractions in caffeine-treated rat myocardium.

Skinned fiber preparations are used to obtain the maximal contractile activation of isolated myocardial preparations. Tetanic contractions elicited in the presence of sarcoplasmic reticulum inhibitors have also been used as an alternative method to produce maximal active tension in the intact myocardium. In this work our purpose was to define the best conditions to obtain tetanic contractions in the rat myocardium and to compare the influence of muscle length and inotropic interventions (Ca2+ and Bay K 8644) in the tension produced in twitches and tetanic contractures.

Changes in collagen content in the residual myocardium surviving after infarction in rats. Influence of propranolol or hydralazine therapy.

The changes occurring in the collagen content in the residual myocardium after infarction have been poorly studied. The aim of this study was to determine the changes in the collagen content in the right and left ventricular muscle of chronically infarcted hearts. Male albino rats were submitted to ligature of the left coronary artery to produce infarction (Inf).

Influence of the sarcoplasmic reticulum on the inotropic responses of the rat myocardium resulting from changes in rate and rhythm.

1. The role of the sarcoplasmic reticulum (SR) in the inotropic responses produced by changes in stimulation rate and rhythm and resting tension was investigated in the rat myocardium. 2.

Effects of isoproterenol on the mechanical activity of isolated papillary muscles and perfused rat hearts in various calcium concentrations.

The aim of the study was to examine, in papillary muscles and in a whole heart preparation, the effects of isoproterenol on the myocardial mechanical activity at different extracellular Ca2+ concentrations. Papillary muscles from left ventricles, contracting isometrically, and rat hearts perfused by the Langendorff technique developing isovolumetric pressure at a fixed rate (200 bpm) and diastolic pressure of 5 mmHg were studied at different Ca2+ concentrations for analysis of the effects of increasing doses of isoproterenol. Papillary muscles were treated with isoproterenol (0.

Microbiological quality of recreational waters in Araraquara, SP, Brazil.

The microbiological flora of 108 water samples was explored to evaluate the role of recreational waters as a possible source of human diseases in Araraquara, S.P., Brazil.

Mechanisms underlying the genesis of post-rest contractions in cardiac muscle.

1. Post-rest potentiation reflects basic cellular mechanisms that control cardiac muscle contraction. Transmembrane calcium influx, the Na+/Ca2+ exchange and the function of intracellular stores that liberate activator calcium upon activation are some of the mechanisms involved.

[Effects of sympathetic block on post-infarction cardiac hypertrophy and their impact on myocardial contractility].

Purpose: To investigate the effects of chronic subcutaneous administration of reserpine (Res) or propranolol (Prop) on the postinfarction myocardial hypertrophy and the effects of Prop treatment on myocardial contractility in rats.

Methods: Male albino rats (3-month-old) were submitted to left coronary artery ligation to produce myocardial infarction. Rats submitted to a sham-operation were used as controls.