Biomedical subjects
N Akar
Publications and source records attributed to N Akar.
Thromboembolism in beta-thalassemia major.
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A further note on the combination of an alpha chain variant with beta-thalassemia.
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Pharmacokinetics of recombinant human erythropoietin in children with chronic renal failure.
Basal erythropoietin (Epo) levels and single dose-pharmacokinetics of recombinant human erythropoietin (rhuEpo) were investigated in 8 predialysis (PD) patients (mean age 11.6 +/- 1.4 years) and in 8 patients on continuous ambulatory peritoneal dialysis (CAPD) (mean age 12.7 +/- 0.6 years). Basal Epo levels were found to be 1.0 +/- 0.0 mu/ml in PD group, 1.6 +/- 0.7 mu/ml in CAPD group and 8.5 +/- 1.8 mu/ml in control group. Following administration of 50 mu/kg rhuEpo (s.c.) serum Epo concentration (Cmax) was 23.2 +/- 2.5 mu/ml in 18.5 +/- 2.6 hours (tmax) in PD patients and 9.9 +/- 0.8 mu/ml in 26.8 +/- 7.7 hours in CAPD patients. Mean elimination half-lives (t1/2) were 13.3 +/- 1.9 hours and 13.5 +/- 3.0 hours in PD patients and CAPD patients, respectively. The volume of distribution (Vd) was 840.0 +/- 100.0 ml/kg; the clearance (Epo Cl) was 37.0 +/- 5.5 ml/kg/hour in PD patients. These values were significantly lower in PD patients than in CAPD patients (p < 0.05) (Vd; 1500 +/- 240.0 ml/kg; Epo Cl 110 +/- 30.0 ml/kg/hour). During the course of CAPD, more efficient clearance of uraemic toxins that inhibit erythropoiesis and more rapid extraction of erythropoietin by erythroid precursors may cause higher Vd in CAPD patients than in PD patients.
Differential structuring of human populations for homologous X and Y microsatellite loci.
The global pattern of variation at the homologous microsatellite loci DYS413 (Yq11) and DXS8174 and DXS8175 (Xp22) was analyzed by examination of 30 world populations from four continents, accounting for more than 1,100 chromosomes per locus. The data showed discordant patterns of among- and within-population gene diversity for the Y-linked and the X-linked microsatellites. For the Y-linked polymorphism, all groups of populations displayed high FST values (the correlation between random haplotypes within subpopulations, relative to haplotypes of the total population) and showed a general trend for the haplotypes to cluster in a population-specific way. This was especially true for sub-Saharan African populations. The data also indicated that a large fraction of the variation among populations was due to the accumulation of new variants associated with the radiation process. Europeans exhibited the highest level of within-population haplotype diversity, whereas sub-Saharan Africans showed the lowest. In contrast, data for the two X-linked polymorphisms were concordant in showing lower FST values, as compared with those for DYS413, but higher within-population variances, for African versus non-African populations. Whereas the results for the X-linked loci agreed with a model of greater antiquity for the African populations, those for DYS413 showed a confounding pattern that is apparently at odds with such a model. Possible factors involved in this differential structuring for homologous X and Y microsatellite polymorphisms are discussed.
Fetal alcohol syndrome.
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Post-splenectomy thrombosis and haemolytic anaemias.
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Frequency of Factor V (1691 G --> A) mutation in Turkish population.
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Direct detection of Hb C (B6 Glu-Lys) by BseRI analysis.
Hemoglobin C (B6 Glu-Lys) can be identified by different techniques. Here we describe a restriction enzyme digestion protocol (BseRI GAGGAG N10) for direct detection of this variant.
Wilson disease mutations associated with uncommon haplotypes in Mediterranean patients.
This study reports 12 novel mutations of the Wilson disease (WD) gene which have been detected by the molecular analysis of 29 patients of Mediterranean descent carrying uncommon chromosomal haplotypes at the WD locus. These mutations include two nonsense, one splice site and nine missense. The missense mutations lie in regions of the WD gene critical for its function, such as the transmembrane region, the transduction domain and the ATP loop and ATP-binding domain, indicating that they are disease-causing mutations. These new findings improve our knowledge for the role played by functional domains on the ATP7B function.
Verification of Hb O-Arab [beta 121(GH4)Glu-->Lys] by dual restriction enzyme analysis.
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Discrimination of Hb D Los Angeles (B121 Glu-Gln) and Hb Beograd (B121 Glu-Val) by dual restriction enzyme analysis.
Hb D Los Angeles (B121 Glu-Gln) and Hb Beograd (B121 Glu-Val) can be identified by different techniques. Here we describe a dual restriction enzyme digestion protocol (EcoR IG AATTC) and Tsp509 I ( AATT) for the discrimination of these variants.
Tuberculous osteomyelitis: an unusual case of tuberculous infection in a child undergoing continuous ambulatory peritoneal dialysis.
A 10-year-old boy on continuous ambulatory peritoneal dialysis had low-grade fever, pain and tenderness of the right shoulder; he had no history of infection or exposure to tuberculosis. The underlying granulomatous infection was diagnosed by histological examination of bone and the polymerase chain reaction with primer sequences specific for Mycobacterium tuberculosis. Special stains and cultures were negative. The initiation of antituberculous therapy was followed by a sharp improvement in the fever, malaise and shoulder pain within several weeks. Extrapulmonary tuberculosis is common in patients with chronic renal failure on dialysis and the diagnosis is difficult. The clinician must recognise the high and early mortality rate in order to initiate an aggressive diagnostic approach and early therapy.
Effects of calcitonin therapy on osteoporosis in patients with thalassemia.
The aim of this study was to evaluate the effects of calcitonin (CT) treatment on bone pain, osteoporosis, bone fractures and blood chemistry in thalassemic patients. Twenty-four patients with an age range of 10-24 years were included, 14 of whom received 100 IU CT and 250 mg calcium 3 times a week. The others (n = 10) were followed up as a control group with only routine thalassemia therapy. After 1 year of treatment, bone pain disappeared and radiological signs of osteoporosis had improved significantly (p < 0.01) in the treatment group. CT has no important side effects.
GM-CSF in the treatment of Fanconi's anaemia.
We have used recombinant human (rh) GM-CSF in two 12-year-old Fanconi's aplastic anaemia patients. They had not received any previous therapy except blood transfusions. Each patient was given three 21 d courses of rh-GM-CSF, the first two at a dose of 3.5 micrograms/kg/d and the third at 7 micrograms/kg/d s.c. There were significant increases in WBC and absolute neutrophil counts after the first week of rh-GM-CSF which lasted as long as the treatment was continued. Following the cessation of treatment, WBC and ANC dropped rapidly. We conclude that rh-GM-CSF can be used in FAA, especially in severely neutropenic cases.
Further notes on neural tube defects and Chernobyl.
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DDAVP shortens bleeding time in Bernard-Soulier syndrome.
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Burkitt's lymphoma between African and American types in Turkish children: clinical, viral (EBV), and molecular studies.
Seventy-two Turkish children with Burkitt's lymphoma (BL) observed during a period of 22 years (1968-1990) have been analysed retrospectively. The diagnosis was established histologically according to WHO criteria. BL represented 50% of NHL in this series. The patients were staged according to Ziegler's system. The median age of patients was 5.5 years with a sex (M/F) ratio of 2.1/1. The most common primary site of tumor involvement was the abdomen (69.4%), which was followed by facial tumors, in particular the jaw and orbit (49.9%). There were 21 cases with jaw (29.1%) and 15 cases with orbital involvement (20.8%) at initial presentation. The majority of the patients (84.4%) were in advanced stages (C and D) at initial diagnosis. Facial tumors observed in Turkish children with BL were more similar to African Burkitt's lymphoma than American or European cases. High titers of antibodies against VCA and EA of EBV were also seen in our recent cases of BL. Two main treatment regimens, namely, single agent chemotherapy with cyclophosphamide (CYX) (1968-1974) and three drug (COM) combination chemotherapy, were used consecutively (1974-1988). COM has been shown to produce better results than single agent therapy. The clinical presentation, mean age, and high antibodies (IgG) to EBV and preliminary molecular studies revealed that BL appears to be in between African and non-African types in Turkish children. This will be further elucidated by direct examination of tumor cells for EBV and investigation of the molecular characteristics of Turkish tumors. Such studies are presently under way.