PubMed Health⌕ Search

Biomedical subjects

N Akar

Publications and source records attributed to N Akar.

At least 109 records · Page 6Linked to original sources
PubMed1992

The molecular basis of beta-thalassemia in Turkey.

By using oligonucleotide hybridization, restriction endonuclease analysis and direct sequencing of amplified genomic DNA, we have been able to characterize 18 different mutations in the beta-globin genes of 161 beta-thalassemia homozygotes and 107 beta-thalassemia heterozygotes from Turkey (429 beta-thalassemia chromosomes). Previous studies dealing with beta-thalassemia in Mediterranean countries have shown that, in most Mediterranean populations, only a few mutations are prevalent. In contrast, beta-thalassemia in Turkey does not seem to be associated with a few predominant mutations. The six most frequent alleles, IVS-I-110 (G----A), IVS-I-6(T----C), FSC-8 (-AA), IVS-I-1(G----A), -30(T----A) and FSC-5 (-CT), account for only 69.3% of the disease genes; indeed, all 26 mutations assayed represent 85.8% of the disease genes, confirming the considerable molecular heterogeneity of beta-thalassemia among Turks, and indicating the possible presence of rare, previously undefined, mutations in the population. Two mutations observed in this study, IVS-I-116 (T----G) and Cd44(-C), have not been reported in the Turkish population to date. Since preventive medical services, such as genetic counseling and prenatal diagnosis, are greatly improved by detailed knowledge of the molecular pathology of beta-thalassemia, we strongly believe that the presented data will facilitate the intended establishment of a prenatal diagnosis center, based on DNA analysis, in Turkey.

Alleles↗
PubMed1992

Isolated growth hormone (GH) deficiency type IA associated with a 45-kilobase gene deletion within the human GH gene cluster.

A Turkish family of seven individuals (two parents and five offspring) is described in which three children presented with isolated GH deficiency type IA, as defined by Illig et al. The gene deletion responsible for the isolated GH deficiency was characterized by Southern blotting and hybridization analysis of genomic DNA using a 32P-labeled hGH cDNA clone as a probe. In the affected patients, a total of approximately 45 kilobases of DNA, encompassing the human (h) GH-1, human chorionic somatomammotropin-L (hCS-L), hCS-A, and hGH-2 genes, were deleted. The end points of the deletion lay within two regions of highly homologous DNA sequence situated 5' to the hGH-1 gene and 5' to the hCS-B gene. The retention of only the hCS-B gene was associated with normal weight and length at birth and normal postpartum lactation in the mother heterozygous for the deletion. The parents, who are consanguineous, both presented with a DNA restriction pattern consistent with heterozygosity for this deletion.

Adolescent↗
PubMed1992

Epstein-Barr virus genotypes in AIDS-associated lymphomas are similar to those in endemic Burkitt's lymphomas.

PCR was used to screen EBV-positive lymphomas from endemic and sporadic Burkitt's lymphoma patients, including EBV-positive lymphomas derived from patients with HIV infection. Only 10% of sporadic lymphomas from either North America (1/15) or South America (2/14) were associated with the type 2 EBV strain, whereas 50% (8/16) of lymphomas from equatorial Africa and 46% (10/22) of HIV-associated lymphomas were positive for the type 2 strain. These data, in conjunction with previous reports, suggest that the proportions of strain types in Burkitt's lymphoma reflect the proportions of strain types in peripheral lymphocytes, and not simply the prevailing regional strain. The increased association of the type 2 strain in lymphocytes and lymphomas from HIV-infected individuals and from Africa may be a result of intermittent (malaria) or continuous (HIU) compromise of immune function in these populations.

Africa↗
PubMed1991

Maternal hair zinc concentration in neural tube defects in Turkey.

Hair zinc concentration was measured in samples taken from 57 mothers who delivered infants with neural tube defects (NTD) (mainly anencephaly). Control groups consisted of 30 healthy mothers with normal offspring and 37 nonpregnant women from middle-income backgrounds. Zinc concentration was also measured in the hair of eight infants with NTD (four being anencephalic). The mean maternal hair zinc concentration in the NTD group (128.2 +/- 38.9 micrograms/g) was lower than that of the control women (p less than 0.001), whereas the mean hair zinc level of malformed babies (250.4 +/- 85.2 micrograms/g) was significantly higher than that of normal infants (193.4 +/- 39.2 micrograms/g) (p less than 0.05). Maternal nutritional zinc deficiency was thought to be one of the factors responsible for NTD in Turkey.

Adolescent↗
PubMed1991

Effect of zinc supplementation in a Turkish woman with two previous anencephalic infants.

The authors report a case of nutritional zinc deficiency in a young (18-year-old) Turkish woman, who previously delivered 2 anencephalic stillborn infants. The patient was supplemented with 22.5 mg oral zinc sulfate (100 mg ZnSO4.7H2O) for 5 months after her second delivery prior to her third pregnancy. Her blood (plasma and red blood cell) and hair zinc levels returned to normal following zinc supplementation. Good response to Zn supplementation was another criterion of Zn deficiency in this particular case. After an uneventful gestational period, she delivered an apparently normal full-term male child who has grown normally during the first 12 months.

Adolescent↗
PubMed1988

High incidence of neural tube defects in Bursa, Turkey.

A radiological survey of 1204 members of the population of Bursa revealed a high prevalence of spina bifida occulta (16.3%). Hospital deliveries in the area also showed a high incidence of anencephalus and spina bifida aperta (5.8 per 1000 total births) in the years 1983 to 1986. In the first 6 months of 1987, however, there was an increase in incidence to 20 per 1000 births (P less than 0.01). The possibility is raised that the Chernobyl disaster of May 1986 might have resulted in the elevation of the rate in an already susceptible population.

Humans↗
PubMed1988

Zinc status in pregnancy and the occurrence of anencephaly in Turkey.

Serum and hair zinc concentrations were measured in samples taken from 29 mothers with neural tube defects (NTD) (mainly anencephaly) at delivery. The control group consisted of 20 healthy mothers with normal offspring and 40 nonpregnant women 18 to 34 years of age, from middle income backgrounds. The mean maternal serum and hair zinc concentrations in the NTD group were lower than those of control mothers and the nonpregnant women. The zinc levels in the blood (plasma, red blood cells) and hair of 8 newborn infants with NTD (4 being anencephalic) were compared with those of normal newborn infants. The mean zinc concentration in the hair of malformed babies (250.4 +/- 85.2 micrograms/g) was significantly higher than that of normal infants (193.4 +/- 39.2 micrograms/g) (p less than 0.05) while the mean plasma zinc concentration was significantly lower (59.48 +/- 9.18 micrograms/dl compared with 68.75 +/- 10.89 micrograms/dl) (p less than 0.01). No difference was found between the mean values of red blood cell zinc levels for the two groups of infants. Maternal zinc deficiency was thought to be one of the factors responsible for NTD in Turkey.

Adolescent↗
PubMed1987

Effects of zinc supplementation on linear growth in beta-thalassemia (a new approach).

Linear growth was evaluated in 32 patients with beta-thalassemia major. At the beginning of the study of 40.6% of the patients were below the 10th percentile with biochemical evidence of zinc deficiency. Effects of zinc supplementation on growth velocity (height) were assessed in a controlled manner. Twenty-one children received oral zinc sulphate for a period of 1 to 7 years (15 early- and 6 late-supplemented cases), while the remaining 11 thalassemics were maintained only on conventional transfusion therapy. The mean height velocity of early-zinc supplemented children was significantly greater than that of normal children (P less than 0.01). An increase in height was also observed in the patients who received delayed zinc retardation. The present study demonstrated that zinc deficiency is one of the factors responsible for retarded linear growth in beta-thalassemia major. Only the patients who received zinc supplementation showed an acceleration of growth in height. Administration of zinc could, therefore, be considered as an effective adjuvant therapy in homozygous beta-thalassemia.

Adolescent↗