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Biomedical subjects

A Aghamohammadi

Publications and source records attributed to A Aghamohammadi.

12 recordsLinked to original sources
PubMed2006

Pulmonary complications in primary hypogammaglobulinemia: a survey by high resolution CT scan.

BACKGROUND: Primary hypogammaglobulinemia disorders are a group of heterogeneous immunodeficiency syndromes with an increased susceptibility to pulmonary complications. METHODS: The aim of this study was to evaluate the extent of lung abnormalities in primary hypogammaglobulinaemic patients by high resolution computed tomography (HRCT) scan and pulmonary function test (PFT). HRCT and PFT were performed in 22 Iranian patients with primary hypogammaglobulinemia. RESULTS: Pathological bronchial findings were observed in thirteen patients: three patients showed only peribronchial thickening and the remaining ten patients suffered from both bronchiectasis and peribronchial wall thickening. Mild type of bronchiectasis and peribronchial wall thickening were the most common type, predominantly observed in the right middle and both right and left lower lobe segments of lungs. Although bullae were not found, emphysema, air-trapping, and collapse/consolidation were observed in two patients. Bronchial involvement was mostly limited to 1 up to 5 bronchopulmonary segments; only one HRCT indicated bronchial involvement in more than nine bronchopulmonary segments. Pathological bronchial findings mostly observed in the proximal bronchi; meanwhile the involvement of the distal bronchi was less common. Decreasing FEVI and FVC were observed in 65% and 55% of patients, respectively. There was a significant correlation between the HRCT score and the predicted values by PFT. The delay of diagnosis in patients with bronchiectasis was significantly higher than those without bronchiectasis. CONCLUSIONS: It seems that the majority of hypogammaglobulinaemic patients suffer from the mild type of bronchiectasis, which is mostly observed in the proximal bronchi of the lower lobe segments. The delay of diagnosis plays an important role in the occurrence of this complication in these patients.

Adolescent↗
PubMed2005

Distribution of primary immunodeficiency disorders diagnosed in the Children's Medical Center in Iran.

Primary immunodeficiency disorders include a variety of diseases that render patients more susceptible to infections. To determine the percentage of different primary immunodeficiency disorders diagnosed in the Children's Medical Center Hospital affiliated to Tehran University of Medical Sciences in Iran, we retrospectively reviewed the charts of the patients being referred to our hospital for immunologic evaluation of recurrent infections during a 20 year period. Among these patients, antibody deficiencies were the most frequent ones and were found in 52.6% of patients (n = 130). T-cell disorders, phagocytic disorders and complement deficiencies were found to be present in 24.69% (n = 61). 22.2% (n = 55) and 0.4% (n = 1) respectively. On the whole, common variable immunodeficiency was the most frequent disorder (n = 65), followed by ataxia telangiectasia (n = 39), X-linked agammaglobulinemia (n = 33), chronic granulomatous disease (n = 29) and selective IgA deficiency (n = 20). This study reveals that antibody deficiencies are the most common type of disorders as shown in other studies. A comparative study shows some differences between our results and other registries. This article also indicates that immunodeficiency disorders should be considered in patients with recurrent infections.

Adolescent↗
PubMed2004

Static and dynamic phase transitions in multidimensional voting models on continua.

A voting model (or a generalization of the Glauber model at zero temperature) on a multidimensional lattice is defined as a system composed of a lattice, each site of which is either empty or occupied by a single particle. The reactions of the system are such that two adjacent sites, one empty, the other occupied, may evolve to a state where both of these sites are either empty or occupied. The continuum version of this model in a D-dimensional region with a boundary is studied, and two general behaviors of such systems are investigated, the stationary behavior of the system, and the dominant way of relaxation of the system toward its stationary state. Based on the first behavior, a static phase transition (discontinuous changes in the stationary profiles of the system) is studied. Based on the second behavior, a dynamical phase transition (discontinuous changes in the relaxation times of the system) is studied. It is shown that the static phase transition is induced by the bulk reactions only, while the dynamical phase transition is a result of both bulk reactions and boundary conditions.

Journal Article↗
PubMed2004

Major histocompatibility complex class I and II antigens frequencies in Baloch ethnic group living in the southeast region of Iran.

BACKGROUND: Human leukocyte antigens have become key components to investigate the genetic relationships between populations. OBJECTIVE: The aim of this study was to determine the genetic diversity of HLA class I and II alleles among the Baloch ethnic group of southeastern in comparison with the Parsi ethnic group, thereby establishing a database for further investigations on the ancestry and genetic factors contributing to complex diseases in this region. MATERIALS AND METHODS: Thirty unrelated Balochi individuals from southeast Iran and 108 Parsi unrelated individuals were serologically typed using standard microcytotoxicity assays with commercial and local trays. RESULTS: The most frequent class I alleles of the Baloch ethnic group were HLA-A01 (53.3%), -A02 (30%), -A09 (23.3%), -A11 (20%), -A23 (23.3%), -B05 (53.3%), and -B08 (26.7%). The class II alleles more frequently observed were HLA-DR1 (26.7%), -DR2 (43.3%), -DR3 (20%), -DR4 (33.3%), -DR7 (26.7%), -DR11 (33.7%), -DRw52 (83.3%), -DRw53 (36.7%), -DQ1 (46.7%), -DQ2 (20%), and -DQ3 (40%). In contrast with the Parsi ethnic group, the frequencies for the following alleles were significantly higher in Baloch than Parsi. HLA-A01, -A23, -A25, -B05, -B08, -B16, -B17, -B60, -DR14, -DQ4, and -DQ7. In contrast, the frequencies of HLA-Cw4 and -DQ3 alleles in the Parsi were significantly higher than the Baloch ethnic group. CONCLUSIONS: This first study of HLA in widely dispersed areas of Iran represents an important resource for investigators in the fields of transplantation immunology and population genetics.

Ethnicity↗
PubMed2004

Oral manifestations in selective IgA deficiency.

Selective immunoglobulin A (IgA) deficiency is the most common of the primary immunodeficiencies with a frequency of 1/300-1/3000, depending on the screened population. As secretory IgA (SIgA) has a protective role in mucosal surfaces from invasion of microorganisms, it is thought that IgA-deficient subjects are susceptible to periodontal diseases and oral manifestations. Previous studies show contradictory results, concerning the involvement of the individuals' periodontium with IgA deficiency. The aim of this study was to investigate and compare the oral manifestations in IgA-deficient subjects with controls. Eleven selective IgA-deficient subjects aged 3-18 years with serum IgA levels <10 mg dl(-1) and 11 age-sex-matched healthy children as the controls entered the study. Oral mucosal investigation, dental caries, plaque accumulation and periodontal status were assessed. Serum immunoglobulin levels were measured by single radial immunodiffusion (SRID) method. Saliva immunoglobulins and secretory component levels were measured by enzyme linked immunosorbent assay (ELISA) methods. IgA-deficient patients had serum and saliva IgA levels less than 10 mg dl(-1) and 10 microg ml(-1), respectively, but other serum immunoglobulin levels were normal and saliva immunoglobulin M (IgM) levels were increased, compared with controls. There were no significant differences in oral manifestations between IgA-deficient subjects and controls, which may be a result of compensatory increase of saliva IgM or other non-immunological defence factors in saliva. Thus, it is not necessary to evaluate IgA and SIgA in all the patients with oral and dental lesions and it is thought that it is better to investigate other factors.

Adolescent↗
PubMed2002

Cluster approximation solution of a two-species annihilation model.

A two-species reaction-diffusion model, in which particles diffuse on a one-dimensional lattice and annihilate when meeting each other, has been investigated. Mean-field equations for general choice of reaction rates have been solved exactly. The cluster mean-field approximation of the model is also studied. It is shown that the general form of large time behavior of one- and two-point functions of the number operators are determined by the diffusion rates of the two type of species, and is independent of annihilation rates.

Journal Article↗
PubMed2001

Autonomous multispecies reaction-diffusion systems with more-than-two-site interactions.

Autonomous multispecies systems with more-than-two-neighbor interactions are studied. Conditions necessary and sufficient for the closedness of the evolution equations of the n-point functions are obtained. The average numbers of the particles at each site for one species and three-site interactions, and its generalization to the more-than-three-site interactions, are explicitly obtained. Generalizations of the Glauber model in different directions, using generalized rates, generalized numbers of states at each site, and generalized numbers of interacting sites, are also investigated.

Journal Article↗
PubMed2001

Exactly solvable models through the empty-interval method.

The most general one dimensional reaction-diffusion model with nearest-neighbor interactions that can be solved exactly through empty-interval method has been introduced. Assuming translationally invariant initial conditions, the probability that n consecutive sites are empty, E(n), has been exactly obtained. Here, however, we do not consider reactions changing two empty neighboring sites. In the thermodynamic limit, the large-time behavior of the system has also been investigated. Releasing translationally invariance, the evolution equation for the probability that n consecutive sites, starting from the site k, are empty, E(k,n), is obtained. In the thermodynamic limit, the large time behavior of the system is also considered. Finally, the continuum limit of the model is considered and the empty-interval probability function is obtained.

Journal Article↗
PubMed2001

Phase transition in an asymmetric generalization of the zero-temperature q-state Potts model.

An asymmetric generalization of the zero-temperature q-state Potts model on a one-dimensional lattice, with and without boundaries, has been studied. The dynamics of the particle number, and especially the large time behavior of the system, has been analyzed. In the thermodynamic limit, the system exhibits two kinds of phase transitions, a static and a dynamic phase transition.

Journal Article↗
PubMed2000

Multispecies reaction-diffusion systems

Multispecies reaction-diffusion systems, for which the time evolution equations of correlation functions become a closed set, are considered. A formal solution for the average densities is found. Some special interactions and the exact time dependence of the average densities in these cases are also studied. For the general case, the large-time behavior of the average densities has also been obtained.

Journal Article↗