Family case of Potocki-Lupski syndrome.

BACKGROUND: Potocki-Lupski syndrome (PTLS, OMIM # 610883) is a rare genetic developmental disorder resulting from a partial heterozygous microduplication at chromosome 17p11.2. The condition is characterized by a wide variability of clinical expression, which can make its clinical and molecular diagnosis challenging. CASE PRESENTATION: We report here a family (mother and her two children) diagnosed with PTLS. When examining children, neurological and psychological (neuropsychiatric) manifestations (speech delay, mild mental retardation), motor disorders, craniofacial dysmorphism (microcephaly, dolichocephaly, triangular face, wide bulging forehead, long chin, antimongoloid slant, "elfin" ears) were revealed. The suspected clinical diagnosis was confirmed by MLPA and CMA molecular genetic testing which revealed the presence of a segmental aneusomy; microduplication in the 17p11.2 region. CONCLUSIONS: Children with PTLS can have a clinically recognizable and specific phenotype: craniofacial dysmorphism, motor and neurological manifestations, which may implicate a possible genetic disease to the attending physician. Moreover, each child with this syndrome is unique and may have a different clinical picture. The management of such patients requires a multidisciplinary team approach, including medical genetic counseling.

[Quantitative assessment of platelet morphofunctional activity based on the data from atomic force microscopy].

Whether atomic force microscopy might be used for the quantitative assessment of platelet morphofunctional activity was studied. The details of the structure of their surface were found to be better detectable when the platelets were fixed with methanol. The authors show it possible to use atomic force microscopy in the studies of platelet functional activity on the donor platelet concentrate specimens.

Kinetics of hybridization on surface oligonucleotide microchips: theory, experiment, and comparison with hybridization on gel-based microchips.

The optimal design of oligonucleotide microchips and efficient discrimination between perfect and mismatch duplexes strongly depend on the external transport of target DNA to the cells with immobilized probes as well as on respective association and dissociation rates at the duplex formation. In this paper we present the relevant theory for hybridization of DNA fragments with oligonucleotide probes immobilized in the cells on flat substrate. With minor modifications, our theory also is applicable to reaction-diffusion hybridization kinetics for the probes immobilized on the surface of microbeads immersed in hybridization solution. The main theoretical predictions are verified with control experiments. Besides that, we compared the characteristics of the surface and gel-based oligonucleotide microchips. The comparison was performed for the chips printed with the same pin robot, for the signals measured with the same devices and processed by the same technique, and for the same hybridization conditions. The sets of probe oligonucleotides and the concentrations of probes in respective solutions used for immobilization on each platform were identical as well. We found that, despite the slower hybridization kinetics, the fluorescence signals and mutation discrimination efficiency appeared to be higher for the gel-based microchips with respect to their surface counterparts even for the relatively short hybridization time about 0.5-1 hour. Both the divergence between signals for perfects and the difference in mutation discrimination efficiency for the counterpart platforms rapidly grow with incubation time. In particular, for hybridization during 3 h the signals for gel-based microchips surpassed their surface counterparts in 5-20 times, while the ratios of signals for perfect-mismatch pairs for gel microchips exceeded the corresponding ratios for surface microchips in 2-4 times. These effects may be attributed to the better immobilization efficiency and to the higher thermodynamic association constants for duplex formation within gel pads.

Evaluation of hybridisation on oligonucleotide microarrays for analysis of drug-resistant Mycobacterium tuberculosis.

A molecular approach was developed to identify drug-resistant strains of Mycobacterium tuberculosis by means of biochips with oligonucleotides immobilised in polyacrylamide gel pads. The technique was based on multiplex PCR, followed by hybridisation on an oligonucleotide microarray, and detected > 95% of rifampicin-resistant and c. 80% of isoniazid-resistant M. tuberculosis isolates within 12 h. In total, 220 drug-resistant isolates and 131 clinical samples were tested using biochips. The sensitivity and specificity of the developed method were comparable with those of standard bacteriological testing of M. tuberculosis drug resistance.

Discrimination between perfect and mismatched duplexes with oligonucleotide gel microchips: role of thermodynamic and kinetic effects during hybridization.

The efficiency of discrimination between perfect and mismatched duplexes during hybridization on microchips depends on the concentrations of target DNA in solution and immobilized probes, buffer composition, and temperature of hybridization and is determined by both thermodynamic relationships and hybridization kinetics. In this work, optimal conditions of discrimination were studied using hybridization of fluorescently labeled target DNA with custom-made gel-based oligonucleotide microchips. The higher the concentration of immobilized probes and the higher the association constant, the higher the concentration of the formed duplexes and the stronger the corresponding fluorescence signal, but, simultaneously, the longer the time needed to reach equilibrium. Since mismatched duplexes hybridize faster than their perfect counterparts, perfect-to-mismatch signal ratio is lower in transient regime, and short hybridization times may hamper the detection of mutations. The saturation time can be shortened by decreasing the probe concentration or augmenting the gel porosity. This improves the detection of mutations in transient regime. It is shown that the decrease in the initial concentration of oligonucleotide probes by an order of magnitude causes only 1.5-2.5-fold decrease of fluorescence signals after hybridization of perfect duplexes for 3-12 h. At the same time, these conditions improve the discrimination between perfect and mismatched duplexes more than two-fold. A similar improvement may be obtained using an optimized dissociation procedure.

[Development of microchips for the detection of mutations of HIV-1 variability to protease inhibitors and the usage results]. / Razrabotka biologicheskikh mikrochipov dlia vyiavleniia mutatsii ustoichivosti VICH-1 k ingibitoram proteazy i rezul'taty ikh primeneniia.

An original biochip was constructed for the detection of 34 mutations of HIV-1 resistance to protease. A technology was worked out, which is based on the hybridization of a fluorescence-labeled amplified fragment of the pol gene of the HIV-1 provirus DNA with a set of specific oligonucleotides immobilized in 3-D hydrogel pads of the biological microchip. The biochip was used to analyze 115 samples of the subtype-1 provirus HIV-1 DNA isolated from untreated IDUs and their sexual partners in 15 regions of former USSR countries. Substitution of Val/IIe in position 77 of protease (V771) is known as secondary mutation of resistance to Nelfinavir detected in 55 (47.8%) of 115 HIV-1 variations. Its first appearance was registered in a patient with HIV in April 1997 in Tver, where its carrying variant caused an HIV outbreak. It is demonstrated that the V771-substitution variant, that dominates in Moscow, caused outbreaks in Irkutsk and Yekaterinburg and spread into separate districts of Perm and Perm Region. At the same time, no V771 HIV-1 was detected in any of the HIV studied cases diagnosed before 1998 in Moldova, Ukraine and Rostov Region.

[New technologies in the determination of drug susceptibility in Mycobacterium tuberculosis]. / Novye tekhnologii opredeleniia lekarstvennoi chuvstvitel'nosti Mycobacterium tuberculosis.

A variety of mutations in the genes rpoB, katG, inhA, ahpC, kasA was studied by using different molecular biological methods (conformational polymorphism of single-chain fragments, heteroduplex analysis, biochips) in rifampicin- and isoniazid-resistant Mycobacterium tuberculosis (MBT) strains isolated from patients with pulmonary tuberculosis. Twenty-nine mutation combinations were identified in the MBT strains. The use of biochips is the most promising method for identifying the type of mutations responsible for the simultaneous resistance to rifampicin and isoniazid. Detection of several MBT strains in one patient requires the use a combination of molecular biological and microbiological studies.

Comparison of methods of extracting Salmonella enterica serovar Enteritidis DNA from environmental substrates and quantification of organisms by using a general internal procedural control.

This paper compares five commercially available DNA extraction methods with respect to DNA extraction efficiency of Salmonella enterica serovar Enteritidis from soil, manure, and compost and uses an Escherichia coli strain harboring a plasmid expressing green fluorescent protein as a general internal procedural control. Inclusion of this general internal procedural control permitted more accurate quantification of extraction and amplification of S. enterica serovar Enteritidis in these samples and reduced the possibility of false negatives. With this protocol it was found that the optimal extraction method differed for soil (Mobio soil DNA extraction kit), manure (Bio101 soil DNA extraction kit), and compost (Mobio fecal DNA extraction kit). With each method, as little as 1.2 x 10(3) to 1.8 x 10(3) CFU of added serovar Enteritidis per 100 mg of substrate could be detected by direct DNA extraction and subsequent S. enterica-specific TaqMan PCR. After bacterial enrichment, as little as 1 CFU/100 mg of original substrate was detected. Finally, the study presents a more accurate molecular analysis for quantification of serovar Enteritidis initially present in soil or manure using DNA extraction and TaqMan PCR.