Individual sample conditioning in flow analysis. Determination of N-total in plant materials.

A flow-batch system allowing in-line individual sample matrix matching is proposed for analysis of sample lots with high variability in acidity. The feasibility of the approach is demonstrated in the spectrophotometric determination of total nitrogen in Kjeldahl digests, using a column with a slightly soluble reagent (AgCl). The solutions are sequentially injected by means of an 8-port selecting valve and processed in a mixing chamber that is also used as a monitoring unit.

Immunophenotype of normal and leukemic bone marrow B-precursors in a Brazilian population. A comparative analysis by quantitative fluorescence cytometry.

The distinction between normal and leukemic bone marrow (BM) B-precursors is essential for the diagnosis and treatment monitoring of acute lymphoblastic leukemia (ALL). In order to evaluate the potential use of quantitative fluorescence cytometry (QFC) for this distinction, we studied 21 normal individuals and 40 patients with CD10+ ALL. We characterized the age-related changes of the CD10, CD19, TdT, CD34 and CD79a densities in normal and leukemic BM.

The effect of hypothermia on coagulation and its implications for infiltration in lipoplasty: a review.

Guidelines issued by the American Society for Aesthetic Plastic Surgery and other professional organizations have helped to reduce complications associated with lipoplasty. However, current guidelines for lipoplasty do not address the issue of hypothermia, which can be aggravated by infiltration of large amounts of anesthetic vasoconstrictive solution. In this article, we review the mechanisms of hemostasis and the pathophysiology of hypothermia and suggest measures by which to minimize the effect of hypothermia on coagulation during and after lipoplasty.

A mathematical analysis of TCR serial triggering and down-regulation.

Despite the increasing knowledge on the pathways involved in TCR signal transduction and T cell activation, the molecular mechanism of TCR triggering by ligand, MHC-peptide complexes, is still elusive and controversial. The present paper addresses the controversy on the early events of TCR engagement and triggering. Mathematical modelling techniques are applied to experimental data to infer plausible molecular mechanisms of TCR triggering and down-regulation.

Modelling T-cell-mediated suppression dependent on interactions in multicellular conjugates.

Tolerance to peripheral body antigens involves multiple mechanisms, namely T-cell-mediated suppression of potentially autoimmune cells. Recent in vivo and in vitro evidence indicates that regulatory T cells suppress the response of effector T cells by a mechanism that requires the simultaneous conjugation of regulatory and effector T cells with the same antigen-presenting cell (APC). Despite this strong requirement, it is not yet clear what happens while both cells are conjugated.

Spontaneous epidural hematoma following a shunt in an infant with congenital factor X deficiency. Case report and literature review.

The authors describe a case of an infant with congenital factor X deficiency. The patient presented with a central nervous system hemorrhage followed by hydrocephalus. He underwent a ventriculoperitoneal shunt and, during the postoperative period, developed a spontaneous epidural hematoma, which was evacuated.

Functional diversity of natural IgM.

This paper proposes a method for the quantitative characterization of repertoire diversity of an unknown mixture of antibodies on the basis of its reactivity profile in the quantitative immunoblot (QIB). The QIB is calibrated by measuring the reactivity profiles of supernatants of known 'diversity' (i.e.

Double blind, randomized, placebo controlled clinical trial of methotrexate in systemic lupus erythematosus.

Objective: To evaluate the capacity of methotrexate (MTX) to control mild activity of systemic lupus erythematosus (SLE), and to evaluate the capacity of MTX to reduce steroid requirement, as well as to evaluate the side effects of MTX in patients with SLE.

Methods: A prospective, randomized, controlled, double blind trial. Forty-one patients with SLE began and 37 completed the 6 months of study.

[Neonatal Streptococcus pyogenes meningitis and sagittal sinus thrombosis: case report].

We report a case of Streptococcus pyogenes meningitis in a 18 days year-old-girl with clinical course complicated by sagittal sinus thrombosis. Some aspects of the pathogenesis, treatment and follow-up of the disease are discussed. The world increase of serious streptococcal infections in the last 10 years, probably will become neonatal Streptococcus pyogenes meningitis more frequent in the future and it is important to be alert for the precocious diagnosis and the possible complications of that potentially lethal infection.

Natural and induced tolerance in an immune network model.

It has been proposed that the immune system can be partitioned into central and peripheral immune systems. Recently, Carneiro et al. (1996a, b) proposed a network, model incorporating B and T lymphocytes that explicitly accounts for that partition.

[Prevalence of dyslipidemias in adult ambulatory laboratory tests from different health care providers].

Objective: To detect differences in the prevalence of dyslipidemia in adult ambulatory laboratory tests from three different health care providers, in Salvador-Brazil, 1995.

Methods: The study was carried out using a probabilistic sample of 24 out of 104 laboratories (approximately equal to 25%) which performed the same enzymatic method for lipid tests with the same quality control. Laboratory tests results were separated into three groups, according to health care provider: Sistema Unico de Saúde (SUS, governamental), Health Maintenance Organizations (HMO), and Private or Patients Health Insurance (PHI).

[Prevalence of dyslipidemias in adults in laboratory tests from Salvador, Brazil].

Purpose: To determine the prevalence of dyslipidemia in non-hospital laboratory tests of adults from Salvador, Brazil.

Methods: The study was carried out in subjects from a probabilistic sample of 25% of a total of 104 local laboratories that used the same enzymatic method for lipid analysis with the quality control as recommended by the Brazilian Society of Clinical Analyses. These represented 93% of all non-hospital laboratories of Salvador in 1995.

[Infection in hospitalized diabetics].

Background: To analyse the infectious diseases of inpatient diabetics in a general hospital.

Material And Methods: We selected retrospectively 233 records of diabetics admitted during September, October and November 1990. There were 38 (16.

Further studies on the problem of immune network modelling.

In a previous work we have analysed a family of antibody and B-cell network models (basic AB models) of the immune system. This analysis focused principally on the physiological interpretation of their parameters. Our approach consisted in building a detailed and general mathematical model (referred to as the GIB model) and then simplifying it formally to a version (named the RIB model) that belongs to the family of AB models, but which is more general than the basic AB models.

A model of the immune network with B-T cell co-operation. II--The simulation of ontogenesis.

This paper is based on a new model of the immune network which explicitly incorporates B-T cell co-operation. A major feature of this model is the simplifying assumption that inhibition by anti-TCR soluble Ig is the only possible down-regulatory influence on activated T-cells. This model is capable of coupling with antigens in both an "immune response" mode and a "tolerant" mode.

A model of the immune network with B-T cell co-operation. I--Prototypical structures and dynamics.

Hitherto, "second generation" network models of the immune system have all been restricted to B-lymphocytes and the Ig molecules they produce. These models have not so far been able to provide a convincing mechanism for the distinction between a "Central Immune System" (CIS) composed of a connected network of lymphocyte clones which couple with "self" antigens in a tolerant mode, and a "Peripheral Immune System" (PIS) composed of clones with little or no supra-clonal organization and which produce classical immune responses when interacting with "non-self" antigens. Here, we present a new network model which explicitly incorporates B-T cell co-operation.

[Intracoronary isosorbide mononitrate versus placebo. A double-blind study with quantitative coronary angiography].

Purpose: To evaluate the vasodilation effect of intracoronary isosorbide mononitrate (ISMN) on the coronary arteries, systolic aortic pressure (SAP) and cardiac rhythms.

Methods: Forty patients aged 61 (40-72) years, 30 (75%) male, were randomized to receive on a double blind fashion, 20 mg of ISMN or placebo. The two groups had similar baseline characteristics.

The ontogeny of class-regulation of CD4+ T lymphocyte populations.

The differential class-regulation of CD4+ T lymphocyte populations is believed to play a major role in determining the qualitative behaviour of the immune system, and in the fate of immune responses in particular. In this article we propose a model for the dynamics of the Th1 and Th2 subpopulations. We put forward the concept of an 'antigenic niche' which allows us to postulate that the key feature underlying the regulation of Th differentiation pathways is the population dynamics of the lymphocytes themselves.

The effects of thalidomide treatment on autoimmune-prone NZB and MRL mice are consistent with stimulation of the central immune system.

We describe here some immunomodulatory effects of thalidomide on autoimmune-prone mice. The highly increased synthesis of splenic IgM in NZB mice, of splenic and lymph node IgG of different subclasses in MRL/n mice, and of splenic and lymph node IgG1 in MRL/lpr mice was markedly inhibited by thalidomide treatment. After a single treatment with 3 mg of thalidomide, the following changes were observed in NZB mice: (i) an initial decrease in the numbers of large CD5+ microhigh, and in the numbers of total CD5+ micro-, CD5- microhigh, CD5+ microhigh lymphocyte populations of the pleural cavity followed by a late increase in the numbers of large cells of the three cell populations; (ii) a consistent increase in the numbers of a CD5low microlow pleural lymphoid population; (iii) a consistent reduction in the numbers of splenic large CD5+ B cells and an oscillatory increase in the number of cells with CD5- phenotype; (iv) a late reduction in the numbers of splenic total CD5+ B cells.

Rethinking "shape space": evidence from simulated docking suggests that steric shape complementarity is not limiting for antibody-antigen recognition and idiotypic interactions.

The concept of "shape space" is based on the assumption that the relevant properties of individual molecules can be adequately specified by a finite list of N parameters; and that cij, the affinity between molecules i and j, can be specified by an equation of the form: cij = f(xi, xj), where xi and xj are N-dimensional vectors representing the absolute positions of molecules i and j in an objective, referential "shape space", and f is an appropriate function. We have performed simulated docking of the combining sites of immunoglobulin molecules, based on their crystallographic structures. The results suggest that shape complementarity cannot account for the specificity of idiotypic interactions, since in the simulations each pair of docked proteins had a buried surface area as great as that occurring in known complexes.

Total hysterectomy versus subtotal hysterectomy: which procedure should be performed during the pregnant-puerperal period?

A retrospective study of 40 hysterectomies due to hemorrhage performed at the "Hospital das Clínicas, Faculdade de Medicina de São Paulo", from January 1978 to August 1989 was conducted in order to determine which type of hysterectomy (total or subtotal) is better indicated during the pregnant-puerperal period. We analyzed operating time, quantity of blood derivatives transfused during the intra- and postoperative periods, time of postoperative hospitalization, number of intra- and postoperative complications, and deaths. The results did not show statistically significant differences between the two types of hysterectomy.

The presence of concanavalin A and canatoxin in Canavalia ensiformis DC tissue culture.

Isolated embryos, cotyledons and embryos plusa fragment of cotyledon from seeds of Canavalia ensiformis (jack bean) were cultured in vitro. Concanavalin A and canatoxin cross-reactive material were detected by double immunodiffusion tests. Canatoxin was detectable until 30 days in cultures of embryos, embryos plus cotyledons and hypocotyls.