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Biomedical subjects

O Yegin

Publications and source records attributed to O Yegin.

24 records · Page 2Linked to original sources
PubMed1984

Epstein-Barr virus (EBV)-specific cell-mediated and humoral immune responses in ataxia-telangectasia patients.

As a part of studies on cell-mediated immune (CMI) responses of immunocompromised, Epstein-Barr virus (EBV)-infected patients who can or cannot restrict the proliferation of EBV-transformed B cells, we have studied 16 Turkish patients with ataxia-telangectasia (AT). Fifteen were EBV seropositive; one was seronegative. Among the seropositives, eight had no or only low anti-EBV-determined nuclear antigen (EBNA) antibody titers, while seven had normal anti-EBNA levels. EBV-seropositive and -seronegative healthy Turkish children were used as controls. We have particularly asked the question whether low EBNA antibody titers can be correlated with the level of EBV-specific and -nonspecific cell-mediated immunity. Non-EBV-specific tests included cell count, phenotypical characterization with monoclonal antibodies, assessment of natural killer (NK)-cell activity, and ability to suppress mitogen-induced immunoglobulin production. Two EBV-specific CMI tests were used: outgrowth inhibition (OI) and leukocyte migration inhibition (LMI). The majority of the patients of the low-EBNA antibody group was IgA deficient and had high levels of alpha-fetoprotein (a-FP). Cells reacting with OKT8 monoclonal antibody predominated in both AT patient groups. In contrast, the suppressor activity was present in only a few patients and NK and interferon-activated killing (IAK) activities were normal. EBV-specific cell-mediated responses were defective in seven of eight patients in the low-anti-EBNA group and five of seven patients in the group with normal anti-EBNA titers. It is concluded that AT patients are often defective in their EBV-specific cell-mediated immune responses and with regard to their EBNA antibody levels. These defects are associated with a predominance of T cells reacting with OKT8 monoclonal antibody.

Adolescent↗
PubMed1983

Chemotaxis in childhood.

Developmental aspects of monocyte and neutrophil chemotaxis were evaluated by the agarose and the Boyden chamber methods. Simultaneous measurements of both the distances and the cell counts were carried out by the agarose method. Before 6 years of age monocyte chemotaxis values, determined by the Boyden chamber method, were significantly lower than those of adults. The difference between adults and children were more marked before the age of 1 year (56 +/- 14 microns N = 48 in 0-1 year, 85 +/- 17 microns N = 25 in adults P less than 0.0001). Neutrophil chemotaxis, determined by the agarose method, was significantly lower than adults in newborns. Values increased gradually thereafter and reached to adult levels after the age period of 2-5 years. Before 6 years of age chemotactic indices (chemotaxis/random migration) for both cell count and distance were also significantly lower than adults. In 20 individuals, neutrophil chemotaxis was assessed simultaneously by both the agarose and the Boyden chamber methods and showed good correlation in reference to distance measurements (P less than 0.01). Cell count and distance measurements, by the agarose method, were also well correlated (P less than 0.01) but agarose method and cell count determination seemed to be most sensitive. Distance/cell count ratio was found to be significantly higher in newborns (1.61 +/- 0.45) when compared with adults (1.13 +/- 0.16) (P less than 0.001). Use of age-matched controls in the evaluation of chemotaxis in children, particularly under 5 years of age, is imperative.

Adolescent↗
PubMed1982

The effect of concanavalin-A (Con A) stimulation on lymphocyte subpopulations.

It has been shown that suppressor T lymphocytes can be activated by plant mitogens as Con A. In order to see if there is any change in lymphocyte surface markers in addition to functional activity, lymphocyte subpopulations (E, EA gamma, EAC rosette forming cells) were determined in 18 healthy controls and 16 patients with ataxia-telangiectasia (AT) after 18-24 hour incubation of lymphocytes with or without Con A (10 micrograms/ml per 2 x 10(6) lymphocytes). Without any incubation, the percentage of EA gamma-RFC was higher and E-RFC was lower in AT patients than in controls. In healthy controls the percentage of EA gamma-RFC significantly increased after incubation with Con A, while the patient group did not show any significant difference. In contrast, the percentage of E-RFC cells in AT group showed significant increase after Con A incubation, while this difference was not significant in healthy controls. There was no significant difference in percentage of EAC-RFC with or without Con A incubation in healthy controls and AT patients. These differences between patient and control groups can be explained by the different features in circulating lymphocyte subpopulations.

Ataxia Telangiectasia↗
PubMedDate not supplied

A case of juvenile chronic myeloid leukemia with XX/XXX mosaicism.

Cytogenetic abnormalities are rarely found in patients with juvenile chronic myelogenous leukemia (JCML). In patients with chromosomal abnormalities, chromosomes 7 and 8 are usually involved. A case of JCML with 47 XXX and a 46 XX karyotype is described and the literature is reviewed. To our knowledge, this is the first case ever to have been reported.

Child↗
PubMedDate not supplied

Growth and sexual maturation in children with thalassemia major.

BACKGROUND AND METHODS. Growth and endocrine disturbances are still important problems for patients with thalassemia major, which is a major health problem in southern part of Turkey. In the present study 71 thalassemia major patients over 3 years of age were evaluated for physical and sexual maturation status. RESULTS AND CONCLUSION. Twenty-three patients (32.4%) were below the third centile for height. Growth retardation was more pronounced in patients 10 years of age and up according to height and weight standard deviation scores (SDS). Delay in bone age SDS was found in almost all patients, and 74.5% of our patients over 12 years of age had not yet entered puberty. These results show that growth and endocrine disturbances have significant negative effects in the quality of life of thalassemic patients. More detailed studies will help to solve these problems.

Adolescent↗