ABSTRACT
The purpose of this paper was to introduce the CMH χ2 test and SAS software implementation of the three kinds of R×C contingency table data. The first type was called “two-way unordered R×C contingency table data”. The CMH χ2 test corresponding to this type of data was essentially the Pearson’s χ2 test. The second type was called “R×C contingency table data with an ordinal outcome variable”. The CMH χ2 test corresponding to this kind of data was essentially a rank sum test. The third type was called “R×C contingency table data which was of two ordinal variables with different attributes”. The CMH χ2 test corresponding to the data was essentially Pearson’s correlation analysis or Spearman’s rank correlation analysis. When there were 1 or 2 “ordinal variables” in the R×C contingency table data， it was necessary to “assign or score” the ordinal variables before performing statistical analysis. In the FREQ procedure of SAS/STAT， there were four scoring methods. With different scoring approach， both the expression form and the calculation results of CMH χ2 test statistics could change accordingly.
ABSTRACT
The purpose of this article was to introduce the types of a multiway table data and their corresponding statistical analysis methods. Based on the data types of the result variables， common high-dimensional table data could be divided into the following three categories， namely， the high-dimensional table data with binary variables， multi-valued nominal variables and multi-valued ordinal variables as the result variables. There were two main categories of the statistical analysis methods for the multiway table data. The first category was the generalized difference analysis， in which the contents included "weighted χ2 test""CMH χ2 test" and "Meta analysis"， the second category was the regression analysis， in which the contents included "log linear regression model analysis""Logistic regression model analysis" "probit regression model analysis" and "discrete choice model analysis".
ABSTRACT
The purpose of this article was to introduce the methods for the independence test of a special high-dimensional table （ie g×2×2 table） and its SAS implementation. There were three approaches， in the SAS software and the statistical textbooks， which could be used to perform the independence test for the data of a multiway table. The three kinds of methods were the generalized CMH χ2 test （for short， approach-1）， the weighted χ2 test with the weighted coefficients in its formula （for short， approach-2）， and the weighted χ2 test without the weighted coefficients in its formula （for short， approach-3）， respectively. This article revealed that the “approach-2” and “approach-3” were the same weighted χ2 test essentially， but with different manifestations. It also revealed that the weighted χ2 test statistic estimation was approximately equal to the CMH χ2 test statistic estimation in the “approach-1”. Based on an example and the SAS software， the article introduced the concrete approaches for the independence test of the g×2×2 table data， explained the output results， and made the statistical and professional conclusions.
ABSTRACT
La regulación inmunológica constituye tanto un mecanismo importante para el mantenimiento de la homeostasis del sistema inmune como para el establecimiento de la tolerancia hacia antígenos propios evitando el desarrollo de enfermedades autoinmunitarias. Así mismo, juega un papel relevante en el mantenimiento de la tolerancia periférica mediante el control de una pequeña población de células T circulantes denominadas células T reguladoras (Treg), las cuáles parecen haber migrado del timo durante estadios relativamente tardíos¹. El término "células T reguladoras" se refiere a células que activan o suprimen la función de otras células. Aparentemente, controlan el desarrollo de enfermedades autoinmunitarias (lupus, tiroiditis, diabetes tipo I y enfermedad inflamatoria intestinal entre otras) el rechazo de injertos, y pueden jugar un papel crítico en el control del asma y la alergia.
Immune regulation is both an important mechanism for maintaining immune system homeostasis and for the establishment of tolerance towards self antigens in order to prevent the development of autoimmune diseases. It also plays an important role in maintaining peripheral tolerance by controlling a small population of circulating T cells, called regulatory T cells (Treg), which seems to have migrated from the thymus during relatively late stages¹. The term "regulatory T cells" refers to cells that activate or suppress the function of other cells. Apparently, controlling the development of autoimmune diseases (For instance, lupus, thyroiditis, type I diabetes and inflammatory bowel disease among others), graft rejection and may play a critical role in asthma and allergy.
Subject(s)
Humans , T-Lymphocytes , Autoimmunity , Homeostasis , Immune System , AntigensABSTRACT
Se cree que la habilidad de los macrófagos para procesar y presentar antígenos de Leishmania es necesaria para su eficiente interacción con células T efectoras y con citocinas secretadas localmente, lo cual induce actividad leishmanicida. Receptores de células T (RCT. reconocen péptidos antigénicos asociados a moléculas del Complejo Mayor de Histocompatibilidad (CMH. y esta interacción trimolecular inicia las vías de señalización específicas de antígeno en las células T estimuladas. En el desarrollo de vacunas contra enfermedades producidas por parásitos intracelulares, se recomienda el esclarecimiento de los mecanismos moleculares asociados, particularmente la identificación de péptidos (epítopes de células T. que puedan estimular un RCT dado, es primordial. En este sentido, en nuestro laboratorio consideramos la posibilidad de identificar péptidos naturales de Leishmania spp. capaces de estimular subpoblaciones de células T productoras de citocinas asociadas con protección de la enfermedad. Como primer paso, utilizamos un método descrito por Malik y Strominger (2000., con algunas modificaciones para aislar complejos CMH/II-péptidos. Para este propósito, se infectó una línea celular de monocitos humanos con promastigotes de Leishmania brasiliensis y los complejos expresados se purificaron por cromatografía de inmunoafinidad y se fraccionaron por RT-HPLC. Las fracciones de péptidos obtenidas se analizaron para determinar su capacidad de estimular una respuesta proliferativa de células T y secreción de citocinas. Los resultados obtenidos con células mononucleares de sangre periférica (CMSP. de pacientes infectados con Leishmania, mostraron reactividad importante con dos de las fracciones de péptidos ensayadas, mientras el resto de las fracciones fueron incapaces de inducir estimulación celular con la estrategia utilizada.
The ability of macrophages to process and present Leishmania antigens is thought to be needed for their efficient interaction with effector T cells and locally-delivered cytokines which induce a leishmanicidal activity. T cell receptors (TCR) recognize antigenic peptides associated with the major histocompatibility complex (MHC) molecules, and this trimolecular interaction initiates antigen-specific signaling pathways in the responding T cells. In the development of vaccines for intracellular parasitic diseases, it is of pivotal importance the elucidation of the immunological mechanisms associated with them, particularly, the identification of peptides (T cell epitopes) that can stimulate a given TCR. Thus, we considered the possibility of identifying natural Leishmania spp peptides able to stimulate T cell subpopulations that produce a pattern of cytokines associated with disease protection. As a first step in the study, we used a method described by Malik and Strominger (2000), with significant modifications to isolate CMH/II-peptide complexes. For this purpose, a cell line of human monocytes were infected with promastigotes Leishmaniabraziliensis, and the expressed complexes were purified by immunoaffinity chromatography, and fractionated by RT-HPLC. The HPLC fractions obtained were tested for their capacity to stimulate a T cell proliferative response and cytokine secretion. Results obtained from peripheral blood mononuclear cells (PBMC) from Leishmania-infected patients showed an important reactivity with two of the fractions tested, while the rest of the fractions were unable to induce cell stimulation with the strategy used.
ABSTRACT
An histochemical and immunohistochemical study was carried out to evaluate the mechanisms of immune response of horses experimentally infected by Trypanosoma evansi. For this purpose the HE histochemical stain and the avidin biotin peroxidase method were used. To determine the presence and immunoreactivity of immune cells we used anti-major histocompatibility complex II antibodies. Cellular infiltration fenotype was characterized with the aid of anti-CD3 antibody for T lymphocytes and by anti-BLA 36 antibodies for B lymphocytes. Macrophages were marked with an antibody against myeloid/histyocites antigen (clone Mac387). Lesions in the CNS of experimentally infected horses were those of a wide spread non suppurative encephalomyelitis and meningomyelitis. The severity of lesions varied in different parts of the nervous system, reflecting an irregular distribution of inflammatory vascular changes. Lymphoid perivascular cuffs and meningeal infiltrations were of predominantly composed of T and B cells. The parasite, T. evansi, was not identified in these horses tissues.
Este estudo objetivou caracterizar a resposta imune celular no sistema nervoso central (SNC) de eqüinos com infecção crônica experimental por Trypanosoma evansi. Para este propósito, foram utilizados os métodos histoquímicos (HE) e imunoistoquímicos do complexo avidina-biotina peroxidase (ABC). O fenótipo do infiltrado celular foi caracterizado com o auxílio de anticorpos anti - CD3, para linfócitos T e antiBLA36 para linfócitos B. Os macrófagos foram marcados com anticorpo antiantígenos da linhagem mielóide/histiócitos (Clone Mac387). A lesão no sistema nervoso central (SNC) dos eqüinos infectados com T. evansi foi caracterizada como meningoencefalite e meningomielite não supurativa. A gravidade das lesões variou em diferentes segmentos do SNC, refletindo distribuição irregular das alterações vasculares. A distribuição de células T e B e antígenos do complexo maior de histocompatibilidade classe II foram avaliados dentro do SNC de eqüinos cronicamente infectados com T. evansi. O infiltrado perivascular e meníngeo eram constituídos predominantemente por células T e B. Macrófagos foram raramente visualizados. T.evansi não foi identificado no parênquima do SNC dos eqüinos.
Subject(s)
Animals , Brain/immunology , Brain/parasitology , Histocompatibility Antigens Class II/biosynthesis , Horse Diseases/immunology , Monocytes , Trypanosomiasis/veterinary , Chronic Disease , Horses , Immunohistochemistry , Trypanosomiasis/immunologyABSTRACT
18 years(n=160) were included. CMH method and FPH model were applied to analyse statistically final height of Shanghai children and their midparental height. Results There was a considerable disparity in stature between the Chinese and the Swedish study populations(P