[Study of the association between constitutional exogenous obesity and polymorphism of the apolipoprotein B gene]. / Issledovanie sviazi konstitutsional'no-ékzogennogo ozhireniia s polimorfizmom v lokuse gena apolipoproteina B.

An attempt was made to associate the insertion-deletion (Ins/Del) polymorphism of the apolipoprotein B gene (apoB) with obesity and to identify alleles and genotypes predisposing to this disorder. The apoB Ins/Del allele frequencies observed in the Russian population were similar to those in West European populations and significantly differed from frequencies reported for Asian populations. Patients with obesity did not differ from healthy individuals in allele and genotype frequencies regardless of whether total or sex-stratified samples were compared. Estimation of relative risk for individuals with genotype Ins/Ins did not reveal a significant association between obesity and this genotype. Thus, constitutional exogenous obesity did not prove to be associated with the Ins/Del polymorphism of the apoB gene in the Russian population.

[Analysis of DNA excreted from the body as an approach to diagnosis and monitoring tumor growth]. / Analiz ékskretiruemoi iz organizma DNK kak podkhod k vyiavleniiu rastushchei v organizme opukholi.

Proceeding from their early data showing that some portion of DNA originating from apoptotic cells can enter the blood stream and pass through the renal barrier by preserving its template capabilities, the authors analyzed urine DNA from 29 patients with colorectal cancer. PCR was used to compare DNA samples from the normal mucosa surrounding the tumor and from the urine collected just prior to surgery. Six microsatellite loci were studied with oligonucleotide primers. The following results were obtained: i) 3 cases showed differences in one of the studied loci in normal and tissue DNA; ii) some patients displayed changes in urine DNA microsatellite loci, namely: disappearance of some alleles (loss of heterozygocity) and appearance of new ones; iii) there were no differences in microsatellite patterns of lymphocytic DNA (taken as a control) and urine DNA in healthy donors. The findings are discussed in view of current concepts of tumor clonal heterogeneity and interpreted as a promising approach to diagnosing and monitoring tumor growth.

[Association analysis of polymorphism in angiotensin-converting enzyme gene in ischemic stroke]. / Analiz assotsiatsii polimorfizma v gene angiotenzinprevrashchaiushchego fermenta pri ishemicheskom insul'te.

Family and twins study demonstrated that genetic factors may be involved in stroke. Previously, insertion/deletion (I/D) Alu-polymorphism in the angiotensin-converting enzyme (ACE) gene has been suggested as a risk factor for some cardiovascular diseases. There fore, cardiovascular factors are well-known risk factors for ischemic stroke. We selected patients with ischemic stroke and with no evidence for arterial hypertension and carried out ACE polymorphism analysis. Association study of I/D polymorphism in group of these patients (52 individuals) and 80 control persons from the same population of Russian descent demonstrated no evidence for statistically significant differences in frequencies of I/D alleles or II/DD/ID genotypes between these groups. Thus, it suggests that ACE I/D polymorphism alone is not risk factor for stroke in non-hypertension patients. We cannot, however, exclude possible interaction between ACE-D/D genotype and sex.

[DNA genotyposcoy in determining paternity: use of hybridized probes]. / Genotiposkopiia DNK v opredelenii spornogo ottsovstva: ispol'zovanie gibridizatsionnykh zondov.

Analysis of hybridization probes for DNA genotypescopy (DNA genotyping and genome fingerprinting) was performed to detect 21 cases of paternity testing. A system with the highly informative multilocus DNA probe Red4, isolated by us earlier, and two single-locus probes (YNH24 and CMM101) detecting highly polymorphic (H > 96%) loci D2S44 and D14S13 was tested. In the cases analyzed, the Red probe was shown to detect, on average, 19.28 +/- 3.6 polymorphic BsuRI fragments in the DNA profile of presumable fathers and 19.67 +/- 5.84 BsuRI fragments in the DNA profile of mothers. The average number of DNA fragments inherited by a child from either parent was approximately equal (8.72 +/- 3.77 and 7.11 +/- 2.66, respectively). The low population frequency of DNA fragments detected by the Red4 probe allowed highly effective positive paternity identification to be performed. Paternity was established in 86% (with probability > 99.75 or > 99.99%) and excluded in 14% of expertises. Single-locus probes YNH24 and CMM101 were used as an additional criterion in cases when, in the DNA profile of a child, a single band (probable de novo mutation) or several bands (probable false paternity or maternity) were revealed but absent in both presumable parents. In once case, a de novo mutation for the YNH24 probe, not described earlier, was revealed. Therefore, a combination of multilocus and single-locus hybridization probes appeared to be the most promising method for significant paternity testing in forensic and medical genetic practice.

[A case of prenatal diagnosis of beta-thalassemia by polymerase chain reaction]. / Sluchai prenatal'noi diagnostiki po povodu beta-talassemii na osnove tekhniki polimeraznoi tsepnoi reaktsii.

The prenatal diagnosis of beta-thalassemia in the Udin family, where the parents were the carriers of 2 bp deletion in the codon 8 (-AA) was undertaken using PCR. Five polymorphic restriction endonuclease sites in the beta-globin gene region were tested. They are: 2 HindIII sites in the gamma G and gamma A genes, 2 HincII sites located in the pseudogene and in its 3'-flanking region, and the AvaIII site in the second exon of the beta-globin gene. The heteroduplex analysis was also performed. Two HindIII polymorphic sites were informative and the HincII site in the pseudogene and the AvaII site in the beta-globin gene were partially informative. According to the results of the RFLP analysis, the embryo was heterozygous. The similar result was obtained by heteroduplex analysis.

[Molecular nature of beta-thalassemia in Tajikistan: a four base pair deletion in codons 41-42 of the beta-globin gene]. / Molekuliarnaia priroda beta-talassemii v Tadzhikistane: deletsiia chetyrekh par osnovanii v kodonakh 41-42 beta-globinobogo gena.

Thirty tajiks, whose relatives had beta-thalassemia traits (revealed in previous investigations by determination of the HbA-2 and HbF levels) were selected to screen beta-thalassemia mutations. DNA samples from each individual were subjected to the PCR (polymerase chain reaction) to amplify the 635 bp beta-globin gene fragment. One additional band was detected in three samples after the amplified fragment underwent electrophoresis in 2% agarose gel and the EtBr was stained, and two additional ones were revealed by 6% PAAGE and staining of the EtBr. All additional bands migrated more slowly than appropriate 635 bp fragment. It is supposed that additional bands are heteroduplexes formed from the wild type chains and mutated chains carrying a deletion or insertion. The 4 bp deletion of the 41-42 (-tctt) was detected after the direct sequencing of the amplified fragments. This mutation is common among Chinese but it was not revealed in the Middle Asia populations. The mutation can be easily screened using the PCR and electrophoresis in 2% agarose gel or PAAG of the amplified beta-globin gene fragments.