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Biomedical subjects

M Telatar

Publications and source records attributed to M Telatar.

34 records · Page 2Linked to original sources
PubMed1996

Ataxia-telangiectasia: mutations in ATM cDNA detected by protein-truncation screening.

We have examined the distal half of the ataxia-telangiectasia (A-T) gene transcript for truncation mutations in 48 A-T affecteds. We found 21 mutations; 4 of the mutations were seen in more than one individual. Genotyping of the individuals sharing mutations, by using nearby microsatellite markers, established that three of the four groups shared common haplotypes, indicating that these were probably founder effects, not public mutations. The one public mutation was found in two American families, one of Ashkenazi Jewish background and the other not. Most truncations deleted the PI3-kinase domain, although some exceptions to this were found in patients with typical A-T phenotypes. All patients not previously known to be consanguineous were found to be compound heterozygotes when mutations could be identified--that is, normal and abnormal protein segments were seen on SDS-PAGE gels. All 48 patients gave RT-PCR products, indicating the presence of relatively stable mRNAs despite their mutations. These results suggest that few public mutations or hot spots can be expected in the A-T gene and that epidemiological studies of A-T carrier status and associated health risks will have to be designed around populations with frequent founder-effect mutations, despite the obvious limitations of this approach.

Ataxia Telangiectasia↗
PubMed1994

Cystic fibrosis patients from the Black Sea region: the 1677delTA mutation.

A 2 bp deletion in exon 10 of the CFTR gene, 1677delTA, which is very rare among CF chromosomes worldwide, was found to be a relatively common cause of cystic fibrosis in countries located in the region of the Black Sea. The frequency of the mutation was compared among cystic fibrosis patients from several populations, namely Bulgarians, Turks, Greek-Cypriots, Georgians, and Russians. The deletion is most common among Georgian CF patients and gradually declines in frequency in neighbouring populations. It is invariably related to a common polymorphic haplotype which is rare among normal chromosomes in Bulgaria but was found to be common in Turkey. The geographic gradient in the frequency of the mutation, along with findings on polymorphic haplotype distribution, suggest that the mutation is relatively young in evolutionary terms and spread as the result of west and south-bound migrations originating from Georgia. The 1677delTA mutation is related to a severe clinical phenotype with a high early mortality rate among homozygotes and possibly to an increased risk of meconium ileus.

Bulgaria↗
PubMed1994

Dinucleotide repeat polymorphism at 11q23.

A highly polymorphic CA repeat sequence was identified near the NCAM gene on chromosome 11q23. It should be a useful marker in the localization of genes responsible for neurological disorders that are known to map to this region.

Base Sequence↗
PubMed1994

Urinary beta 2-microglobulin levels and urinary N-acetyl-beta-D-glucosaminidase enzyme activities in early diagnosis of non-insulin-dependent diabetes mellitus nephropathy.

To assess whether urinary N-acetyl-beta-D-glucosaminidase (NAG) and beta 2-microglobulin (beta 2-MG) levels could be used as predictors of diabetic nephropathy or not, 59 non-insulin-dependent diabetes mellitus (NIDDM) patients were included in our study (31 females, 29 males; mean age 54 +/- 10.1). The control group consisted of 20 healthy non-diabetic subjects (12 males and 8 females; mean age 47 +/- 13.9). The patients in the study group were classified according to the duration of diabetes. In all cases, urinary beta 2-MG levels were measured by specific enzyme immunoassays and urinary NAG enzyme activities were determined by colorimetric methods. The mean urinary NAG level in study group was higher than that of the control group (p < 0.01). It was observed that NAG activity begins to rise in the third year of NIDDM, makes a plateau between 3-10 years, and rapidly increases after the 10th year. No significant difference in NAG activity was found between chemical NIDDM and control groups. No significant difference in beta 2-MG levels was found between study and control groups. The mean NAG activity in patients with early glomerular hyperfiltration was significantly higher than those without early hyperfiltration and control group (p < 0.05), whereas the mean beta 2-MG level was not. As a result, urinary NAG enzyme activity significantly increases, while urinary beta 2-MG level remains unchanged in patients with NIDDM. It was concluded that measurement of urinary NAG enzyme activity may be a good indicator in early diagnosis of diabetic nephropathy.

Acetylglucosaminidase↗
PubMed1993

Papillary carcinoma in a thyroglossal duct remnant with normal thyroid gland.

Carcinoma in the thyroglossal duct remnant is relatively uncommon. Since the first report by Uchermann (1915), more than 150 cases of carcinoma have been reported, and the majority have been papillary thyroid carcinomas (Li Volsi et al., 1974; McNicol et al., 1988). In this report, we present a case of papillary carcinoma in the thyroglossal duct with a normal thyroid gland.

Adolescent↗
PubMed1992

DNA analysis in Turkish Duchenne/Becker muscular dystrophy families.

The molecular genetics of Duchenne/Becker muscular dystrophy was investigated in 81 affected Turkish families. Deletions were detected by multiplex polymerase chain reaction assays and cDNA Southern analyses. The distribution of the deletions along the gene and their correlation to clinical phenotype were different from the studies reported on other populations. Moreover, DNA polymorphisms in mothers were determined using 8 DNA probes and three CA repeat sequences, and a high degree of informativeness was observed.

Chromosome Deletion↗
PubMed1992

Ataxia-telangiectasia: linkage analysis of chromosome 11q22-23 markers in Turkish families.

To further pinpoint the location of the genes for ataxia-telangiectasia on the long arm of chromosome 11, we performed linkage analysis and analysis of recombinants of genetic haplotypes on 14 Turkish families with ataxia-telangiectasia, 12 of which were consanguineous. These studies used more than 25 polymorphic genetic markers spanning a region of the long arm of chromosome 11 that is larger than 50 cM. Seven markers gave significant LOD scores to AT: CJ5, DRD2, CJ208, S144, CD3E, PBGD, and S147, as did haplotypes created with pairs of markers DRD2/CJ5 and S144/CJ208, giving recombination fractions (theta) of 0.00, 0.00, 0.05, 0.08, 0.03, 0.09, 0.07, 0.00, and 0.06, respectively. Monte Carlo analysis of these 14 Turkish families indicated the best location for a single AT gene to be within a 6 cM sex-averaged (3 cM male-specific) interval defined by STMY and CJ77; this was three times more likely than the next most likely location (peak III) at the DRD2 locus. The analysis also revealed a peak (peak II) between S147 and S133, which may represent the complementation group D gene. Recombinant analysis of haplotypes also localized an AT locus to the STMY-CJ77 interval. Taken together, these results suggest that at least two distinct AT loci exist (ATA and ATD) at 11q22-23, with perhaps a third locus, ATC, located very near to the ATA gene. This genetic heterogeneity further complicates plans to isolate the major ATA and ATC genes and to begin identifying AT carriers in the general population.

Ataxia Telangiectasia↗
PubMedDate not supplied

Identical mutation in 55% of the ATM alleles in 11 Norwegian AT families: evidence for a founder effect.

The ATM gene is responsible for the autosomal recessive disorder Ataxia-Telangiectasia (AT). Many different mutations, located all across the gene, have been reported with a predominance of truncating mutations. By using PTT (protein truncation test) a mutation was found in one Norwegian AT family. Sequencing revealed that the mutation affected nucleotides 3245-3247, codon 1082, and changed the sequence from ATC to TGAT, inducing a stop codon downstream at codon 1095 and leading to early truncation of the ATM protein. Perpendicular DGGE (denaturing gradient gel electrophoresis) was used to screen 10 additional families for this mutation. The 3245 delATC insTGAT mutation was found in 12 of 22 proband alleles: five patients were homozygotes and two heterozygotes. Haplotype analyses were performed using eight microsatellite markers, within and flanking the ATM gene. All carriers of the mutation described were found to have a common haplotype of the five closest CA-repeat microsatellite markers. Genealogical investigations of the families identified a common ancestor for three of the families. The common ancestor was a woman born in 1684 in the area from which these families originate. The prevalence of this mutation in Norwegian patients now allows a major subset of AT heterozygotes to be identified, both in the general population and in breast cancer patients, so that their cancer risk can be evaluated.

Ataxia Telangiectasia↗
PubMedDate not supplied

Relationships among nonverbal intelligence, hand speed, and serum testosterone level in left-handed male subjects.

The relationships among nonverbal intelligence, hand speed, and serum testosterone level were studied in male left-handers ranging in age from 17 to 19 years. Hand speed was measured by a peg moving task. To assess the differences between nonverbal IQs. Cattell's Culture Fair Intelligence Test was used. There was a direct correlation between IQ and testosterone. IQ increased linearly with right-hand speed, which was directly related to testosterone. There was no significant correlation between IQ and left-hand speed, which was not significantly correlated with testosterone. IQ decreased with left- minus right-hand speed, which also decreased with testosterone. It was suggested that nonverbal spatial reasoning ability may be directly associated with the efficiency of left brain, which is favored by testosterone in male left-handers. It was also concluded that the left to right asymmetry in hand speed may depend on efficiency of the right brain in left-handed males.

Adolescent↗
PubMedDate not supplied

Inverse relationship between nonverbal intelligence and the parameters of pattern reversal visual evoked potentials in left-handed male subjects: importance of right brain and testosterone.

The relationships between latencies of visual evoked potentials (VEPs) and nonverbal intelligence test scores (IQs from Cattell's Culture Fair Intelligence Test) and correlations between serum testosterone level and VEP latencies were studied to examine the neural speed hypothesis of intelligence and its hormonal mechanisms in left-handed male subjects (Geschwind Scores). In accordance with the speed theory of intelligence, N1 and P1 latencies (and amplitudes) were found to be inversely related to IQ. However, this was true only for the right brain; the left brain did not contribute to this relationship. There was an inverse relationship between serum testosterone level and P1 latency; left minus right N1 latency, depending on N1 latency from right brain, linearly increased with testosterone. It was concluded that nonverbal intelligence largely depends on speed of information processing only by the right brain, not by the left brain in left-handed male subjects. This may have been created by testosterone in these subjects. Inconsistencies in the IQ literature concerning the speed hypothesis of intelligence may be explained by differences in cerebral lateralization.

Adolescent↗
PubMedDate not supplied

Carrier detection by DNA analysis in Duchenne muscular dystrophy families.

We applied DNA analysis techniques to Turkish families whose members were afflicted with Duchenne/Becker muscular dystrophy. The aim of this study was to establish a prenatal diagnosis of this anomaly and to determine the carrier state. All of the techniques used in established diagnosis centers are now applied routinely in our laboratory. Both Southern analysis and polymerase chain reaction (PCR) methods were used for deletion detection in patients and restriction enzyme fragment length polymorphism (RFLP) determination for linkage analysis in women at risk. CA repeated sequence length polymorphism, the most recent technique for linkage analysis, was also applied. About 250 individuals from seventy-nine families were investigated and thirty-six entire families were screened. Twenty-five women were found to be carriers while thirty seven were non-carriers. The carrier state could not be determined in three women.

Chromosome Deletion↗