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Biomedical subjects

N Akar

Publications and source records attributed to N Akar.

At least 73 records · Page 4Linked to original sources
PubMed1999

Evaluation of cardiac functions in patients with thalassemia major.

It is known that a blood transfusion is necessary for survival in patients with thalassemia, but it may cause myocardial dysfunction due to myocardial siderosis as in other organs. The aim of this study was to evaluate myocardial perfusion by means of stress thallium scanning (MPS) and left ventricular functions by rest radionuclide ventriculography (RNV). Twenty-one patients at ages 9-16 (mean 12.1 +/- 3.2) who have been diagnosed with thalassemia for 4-15 years (mean 12.7 +/- 4.8) were included in the study. They had blood transfusions 78-318 times (mean 162.1 +/- 71). MPS and RNV was performed within two days after the any transfusion. MPS showed ischemia in 3 patients and normal perfusion in 18 patients. RNV revealed normal systolic parameters (wall motion, EF, PER, TPE) but diminished diastolic parameters (TPF, PFR) compared with normal values (p < 0.05). We conclude that ischemia or fixed defects may be seen in stress MPS as a result of cardiac involvement in patients with thalassemia. But, RNV is an important and preferable test for the early detection of subclinic cardiomyopathy. RNV may therefore show diastolic abnormalities before the systolic abnormalities show up.

Adolescent↗
PubMed1999

Recombinant human growth hormone treatment in children with thalassemia major.

BACKGROUND: To evaluate the growth hormone reserve and the growth hormone response to recombinant human growth hormone (GH) in prepubertal thalassemic children with growth retardation. METHODS: Twenty thalassemic patients with short stature and delayed bone age were studied. Patients were randomized into GH-treated (n = 10) and non-GH treated (control; n = 10) groups. The GH-treated group received recombinant human (rh)-GH (Genotropin) at the dose of 0.7 IU/kg per week for 12 months. RESULTS: There was a significant discordance between GH response to pharmacologic stimuli and physiological secretion of GH/GHRH testing. Following the administration of rhGH, growth velocity increased from 2.47 +/- 0.48 cm/year to 6.27 +/- 0.76 cm/year (P = 0.005), whereas there was not a similar change in the non-GH-treated group. The height velocities of the two groups during the 1 year follow-up period were significantly different (6.27 +/- 0.76 vs 3.99 +/- 0.34 cm/year; P = 0.025). There were significant differences between the height velocity improvements and height velocity standard deviation scores of the two groups as well. CONCLUSION: The present study has demonstrated that rhGH is a safe and efficacious mode of treatment in thalassemic children.

Adolescent↗
PubMed1999

Factor V1691 G-A, prothrombin 20210 G-A, and methylenetetrahydrofolate reductase 677 C-T variants in Turkish children with cerebral infarct.

Inherited gene defects related to the coagulation system have been reported as risk factors for ischemic stroke. These gene defects include a G-A transition at nucleotide 1691 in exon 10 of the Factor V gene causing activated protein C resistance; a G-A transition in the 3' untranslated region of the prothrombin gene at nucleotide position 20210 (G-A), which is associated with increased levels of prothrombin activity; and a C-T polymorphism at nucleotide 677 in the methylenetetrahydrofolate reductase gene responsible for an alanine to valine substitution, resulting in the synthesis of a thermolabile form of methylenetetrahydrofolate reductase that causes increased levels of homocysteine. The case-control study included 28 patients with cerebral infarction; all were 18 years of age or younger (range, 10 months to 18 years). Seven (25%) of the 28 patients were heterozygous for the FV1691 mutation. Five (17.8%) of the patients carried the PT20210A mutation. Two (7.1%) of the patients carried both mutations. When compared to controls, the difference was significant for both mutations (P = .007; .04). The frequency of allele T of methylenetetrahydrofolate reductase 677 was 0.3214, which was not significant when compared to controls (0.231; P = .3). A total of 12 (42.8%) patients carried one or both of the mutations FV1691 G-A and PT20210 G-A. From our data, it appears that FV1691 G-A and PT20210 G-A are associated with cerebral infarct risk independently. Risk assessment of double prothrombotic gene alterations did not reveal synergy between these mutations. In conclusion, the presence of FV1691 A and PT20210 A mutations but not the methylenetetrahydrofolate reductase 677 TT mutation correlate with the occurrence of cerebral infarction in children.

Adolescent↗
PubMed1999

Mutation analysis in patients of Mediterranean descent with Wilson disease: identification of 19 novel mutations.

In this study, we report further results of mutation analysis of the ATP7B gene in Wilson disease (WD) patients of Mediterranean origin. A total of 136 WD chromosomes, 73 of which were of Italian, 43 of Turkish, 18 of Sardinian, and two of Spanish origin, were analysed and the mutation characterised in 84.5% of them. We found 50 different mutations of which 19 are novel, including three nonsense, one frameshift, and 15 missense mutations. The mutations detected were rare and mostly found in the compound heterozygous state together with other mutations and only rarely in homozygosity. Most of these mutations lie in the transmembrane and ATP binding loop regions. These data expand our knowledge of both the structure-function relationships of the WD protein and the molecular pathology of WD, thus improving our capability of prevention and genetic counselling.

Adenosine Triphosphatases↗
PubMed1998

Search for genetic factors favoring thrombosis in Turkish population.

Common mutations in three genes (MTHFR 677 C-T; MS 2756 A-G; CBS Exon 8,844 ins 68) in homocysteine metabolism have been shown to cause increased plasma homocysteine levels thus causing a predisposition to thrombosis. FV 1691 G-A mutation, which is very common in the Turkish population, was also studied. As there is no existing data in the Turkish population, we aimed to study these mutations in patients with thrombosis and normal controls. The case-control study included 52 patients with the diagnosis of deep vein thrombosis (DVT) and 106 controls, consecutively selected among subjects without personal and family history of atherothrombosis. Patients with DVT were selected if Doppler ultrasonography was positive. The comparison of FV 1691 G-A mutation revealed statistically significant difference in control and DVT group. Risk assessment of double prothrombotic gene alterations indicated only FV 1691 G-A mutation as an independent risk factor for thrombosis, but our data suggested that MTHFR 677 has little effect on its own but may have synergy with FV 1691 G-A. Other possible risk genotypes at the homocysteine pathway did not have a significant effect on thrombosis. Furthermore, being heterozygote at two different loci or homozygosity at least in one locus also did not reveal a significant difference between these two groups in our population.

Case-Control Studies↗
PubMed1998

Further delineation of the molecular pathology of Wilson disease in the Mediterranean population.

This study presents the update results of an ongoing project on the delineation of the spectrum of mutations at the Wilson disease (WD) gene in WD patients of Mediterranean origin. In studying 59 patients, of whom were 26 Continental Italians, 22 Sardinians, 9 Turkish, and 2 Albanians, we have found 31 novel and three known mutations. Of the novel mutations, 3 are deletions, two nonsense, 2 splice or consensus splice site, and 24 missense. The large majority of the missense mutations lie in evolutionary conserved regions of the WD gene of documented functional importance. Most of our patients were compound heterozygotes, and only a few were homozygotes. In addition, three polymorphisms were detected. By adding the new data to those previously reported by our group, we have to date detected 85% of mutations in the WD chromosomes from Continental Italians, 30% from Sardinians, 81.7% from Turkish and 66.7% from Albanians. Most of the mutations characterized are rare, and only a limited number are common. Of the common mutations 5 were found in Continental Italians, two in Sardinians and a single one in Turkish. Because there are so many causative mutations of the disease, the preclinical and prenatal diagnosis of WD should be carried out by a combination of mutation and linkage analysis.

Adenosine Triphosphatases↗
PubMed1998

Deletion polymorphism at the angiotensin-converting enzyme gene in Turkish patients with coronary artery disease.

Coronary artery disease (CAD) is a multifactorial disease in which genetic and environmental factors play an important role. These factors differ in each population. This study was carried out to determine whether there is an association between insertion/deletion (I/D) polymorphism and CAD in Turkish patients from Ankara. An I/D polymorphism in intron 16 of the gene coding for the angiotensin-converting enzyme (ACE) has been used to study the role of this gene in the aetiology of coronary atherosclerosis and hypertension. As there are no existing data for the Turkish population, we studied the I/D polymorphism of the ACE gene in 218 patients with CAD and 107 controls. Polymerase chain reaction (PCR) was used for genotyping the I and D alleles. The DD polymorphism of the ACE gene was significantly different between CAD subjects (0.733) and controls (0.612) (p=0.002). The observed heterozygosity was 29.3% and 43.9% and D allele frequency was 0.733 and 0.612, respectively. There was a significantly higher D allele (p=0.03) in 111 patients with myocardial infarction (MI) compared with controls. Furthermore, MI localization also gave a significance of p=0.002 for inferior MI but not for anterior MI (p=0.83). Forty-three hypertension patients had a D allele frequency of 0.767 which was significantly different from control (p=0.01). These data provide further evidence for the association of D allele and CAD in a Turkish population.

Adult↗
PubMed1998

Homozygous protein C deficiency with a double variant His 202 to Tyr and Ala 346 to Thr.

We present the protein C gene analysis of a patient with homozygous protein C deficiency. The patient was referred with purpura fulminans 3 h after birth. Skin necroses had developed on the scalp, abdomen and upper extremities when he was two days old. His protein C activity was 0.03-0.05 IU/ml and the levels in his consanguineous parents were 0.32 and 0.40 IU/ml. He was treated initially with fresh frozen plasma, and later with daily oral anticoagulants, for two episodes of skin necrosis. He had three more episodes of skin necroses that were treated with intravenous protein C concentrate. He is now two years old and under treatment with daily coumarin 0.1-0.2 mg/kg per day to keep the International Normalized Ratio between 2.0-4.5. DNA analysis showed that he is homozygous for a double variant bearing His 202 to Tyr and Ala 346 to Thr mutations. His parents were each heterozygous for the double variant and were consanguineous. This mutation has been reported previously in an Austrian patient but this is the first homozygous case for this double variant.

Alanine↗