CD38 gene polymorphism rs1130169 contribution to the increased gene expression and risk of colorectal cancer (pilot study)

BACKGROUND

Genetic variations in immune signaling genes may have regulatory effect on phenotypic heterogeneity of immune cells and immune functions, hence promoting tumor growth.

PURPOSE

We compared the frequencies of potentially functional CD38 gene single nucleotide polymorphisms rs1130169 (T > C) in 86 healthy controls and 90 colorectal cancer (CRC) cases to assess their association with cancer risk and CD38 gene expression.

RESULTS

The association between allele C rs1130169 and CRC risk was observed. Allele C was also significantly correlated with an increased CD38 mRNA level and CD38 positive cell percentages in peripheral blood of healthy controls that could be a possible explanation for CRC risk in C allele carriers. In peripheral blood of CRC patients CD38 mRNA and serum soluble CD38 protein levels significantly differed from those in healthy controls. Calculation of the CD38 full-length and with the third exon deletion mRNA ratio in corresponding samples showed that the mRNA isoform ratio was significantly higher in CRC cases than in controls. It suggests that alternative splicing regulates elevation of CD38 full-length mRNA level in peripheral blood of CRC patients. We also have observed higher expression levels of CD38 full-length mRNA in peripheral blood of CRC patients with lymph node metastases compared to patients without metastases.

CONCLUSION

This study indicated biological significance of rs1130169 variations that can alter differences in CRC risk by regulating CD38 gene expression.

[Enteroviral (Picornaviridae: Enterovirus) (nonpolio) vaccines]

Non-polio enteroviruses (NPEVs) are ubiquitous and are one of the main causative agents of viral infections in children. NPEVs most commonly infect newborns and young children, due to their lack of antibodies. In children, clinical manifestations can range from acute febrile illness to severe complications that require hospitalization and lead in some cases to disability or death. NPEV infections can have severe consequences, such as polio-like diseases, serous meningitis, meningoencephalitis, myocarditis, etc. The most promising strategy for preventing such diseases is vaccination. No less than 53 types of NPEVs have been found to circulate in Russia. However, of epidemic importance are the causative agents of exanthemic forms of the disease, aseptic meningitis and myocarditis. At the same time, the frequency of NPEV detection in the constituent entities of the Russian Federation is characterized by uneven distribution and seasonal upsurges. The review discusses the epidemic significance of different types of enteroviruses, including those relevant to the Russian Federation, as well as current technologies used to create enterovirus vaccines for the prevention of serious diseases.

[Detection SARS-CoV-2 (Coronaviridae: Coronavirinae: Betacoronavirus: Sarbecovirus) in children with acute intestinal infection in Nizhny Novgorod during 2020-2021]

INTRODUCTION

The novel coronavirus infection COVID-19 is a major public health problem worldwide. Several publications show the presence of gastrointestinal (GI) symptoms (nausea, vomiting, and diarrhea) in addition to respiratory disorders.The aim of this study was the monitoring of RNA of COVID-19 pathogen, coronavirus SARS-CoV-2 (Coronaviridae: Coronavirinae: Betacoronavirus; Sarbecovirus) in children hospitalized with acute intestinal infection (AII), with following molecular-genetic characterization of detected strains.

MATERIAL AND METHODS

Fecal samples of children with AII hospitalized in infectious hospital of Nizhny Novgorod (Russia) in the period from 01.07.2020 to 31.10.2021 were used as material for the study. Viral RNA detection was performed by real-time polymerase chain reaction (RT-PCR). The nucleotide sequence of S-protein gene fragment was determined by Sanger sequencing.

RESULTS AND DISCUSSION

SARS-CoV-2 genetic material was detected in 45 out of 2476 fecal samples. The maximum number of samples containing RNA of the virus occurred in November 2020 (detection rate of 12.2%). In 20.0% of cases, SARS-CoV-2 RNA was detected in combination with rota-, noro-, and adenoviruses. 28 nucleotide sequences of S-protein gene fragment complementary DNA (cDNA) were determined. Phylogenetic analysis showed that the studied SARS-CoV-2 strains belonged to two variants. Analysis of the S-protein amino acid sequence of the strains studied showed the absence of the N501Y mutation in the 2020 samples, which is a marker for variants with a high epidemic potential, called variants of concern (VOC) according to the World Health Organization (WHO) definition (lines Alpha B.1.1.7, Beta B.1.351, Gamma P.1). Delta line variant B.1.617.2 was identified in two samples isolated in September 2021.

CONCLUSION

The detection of SARS-CoV-2 RNA in the fecal samples of children with AII, suggesting that the fecal-oral mechanism of pathogen transmission may exist, determines the necessity to optimize its monitoring and to develop an algorithm of actions with patients with signs of AII under the conditions of a novel coronavirus infection pandemic.

S. aureus and E. coli change the force and work of adhesion between P- and E-selectins of endothelial cells and ligands of neutrophil granulocytes

Thanks to the modification of the force spectroscopy method, when a neutrophil is fixed on the tip, and an endotheliocyte culture is grown on the substrate, the exact indicators of the adhesion force and adhesion work between cells have been investigated. The high variability of adhesion contacts in different donors associated with different expression profiles of neutrophils. It was found by flow cytometry that the EA.hy926 cell line actively expresses VCAM-1, as well as P- and E-selectin under the Staphylococcus aureus influence after 60 min of co-incubation. At the same time, the integral indicators of the adhesion force and adhesion work in the "neutrophil - endothelial cell" interaction were significantly inhibited by S. aureus in all studied donors. Since the VCAM-1 receptor is not involved in the adhesion bonds between neutrophils and endothelial cells, the suppression of the interaction is associated with the inhibition of P- and E-selectins, but direct receptors removal from the endothelial cells surface of the EA.hy926 cell line does not occur. Escherichia coli causes multidirectional effects in the system of interaction "neutrophil - endothelial cell", depending on the expression profile of the donor's neutrophils. However, the cumulative effect of interaction from all donors shows that in general, under the influence of E. coli, there is an increase in adhesion force and a suppression of adhesion work.

Serum Protein Corona Abolishes Changes in the Expression of Proinflammatory Genes Induced by Quantum Dots in Human Blood Mononuclear Cell

We studied changes in the transcription of genes encoding cytokines (TNF, IL-6, IL-10, and IL-32), cell activation markers (ICAM1, CD38, Fas, and FCGRIII), ROS production catalyst (NOX2), autophagy (Beclin 1, LC3B, and p62) and apoptosis (BAX, BCL2) regulators in peripheral blood mononuclear cells upon contact with quantum dots CdSe/ZnS-MPA and CdSe/CdSeZnS/ZnS-PTVP. Up-regulation of TNF, ICAM1, Fas, p62 mRNA and down-regulation of the FCGRIII and NOX2 mRNA in response to the presence of quantum dots were revealed. The formation of serum protein corona on the surface of quantum dots abolished this effect.

SlyD-deficient Escherichia coli strains: A highway to contaminant-free protein extraction

Binding of native bacterial protein SlyD to metal affinity matrices remains a major problem in affinity purification of His-tagged recombinant proteins from Escherichia coli cells. In this study, four novel E. coli strains that lack the expression of SlyD/SlyX, were engineered using λ-red mediated chromosomal deletion. The resultant mutant E. coli strains allow us to obtain SlyD-free proteins immediately after metal affinity chromatography, and eliminate additional purification processes. As a model protein, bispecific antibodies composed of anti-F4/80 V_HH module and anti-TNF V_HH module (MYSTI-2) were used. Using this protein we have shown that the SlyD/SlyX-deficient E. coli strains allow us to obtain a fully functional protein.

[Cancer-testis genes in colon cancer]

The expression of cancer-testis (CT) genes varies with tumor type. There are tumors with high, low, and intermediate gene expressions. Tumor cells of different origin are characterized by ST gene co-expression. The expression of ST genes increases in later stages of tumor development in the presence of metastases. In colon cancer, the tumor samples showed most frequently MAGE-A and SSX mRNA. The peripheral blood samples displayed most commonly XAGE, MAGE-C, and SSX mRNA. In patients with colon cancer, the expression of TSP50, MAGE-A(1-6), and SSX1,2,4 genes was associated with a poor prognosis, that of MAGE-C1 and XAGE1 was related to a favorable prognosis.

[The correlation of expression of MUC1, ICAM1, IL32, FcyR3A and FoxP3 in tumor niduses of patients with breast cancer]

The hypo-glycated mucin I (MUC I) frequently is redundantly expressed in cells of breast carcinoma that is considered as an unfavorable prognostic marker for patients with breast cancer. The purpose of study is to evaluate in tumor areas of patients with breast cancer the interrelationships between expression of MUC I and genes participating in implementation of immune reactions. The technique of polymerase chain reaction with reverse transcription in real-time was applied to investigate expression of genes of MUC I, Fas, ICAMI, FcyR3A, FcyR3B, FoxP3, IL2Ra, IL32 and TNF in tumor areas of 40 patients with breast cancer. The level of mRNA of each of analyzed genes was evaluated relatively to three genes of household. The rate of detection of mRNA MUC I amounted to 80%, mRNA Fas - 95%, mRNA ICAM I - 97.5%, mRNA FcyR3A - 95%, mRNA FcyR3B - 32.5%, mRNA FoxP3 - 85%, mRNA IL2Ra - 87.5%, mRNA IL32 - 75%, mRNA TNF - 95%. The direct correlation was established between levels of mRNA MUC I, ICAM I, IL32, FcyR3A and FoxP3. The most strong relationship was registered between levels of expression of genes MUC I and IL32 (r-0.72; p=0.0001). In comparison with MUC I negative breast carcinoma, MUC I positive breast carcinoma characterized by higher level of mRNA of pro-inflammatory cytokines IL32 and ЕТА, molecules of adhesion ICAM I and molecular marker of T-regulative cells FoxP3. The given profile of expression of genes in tumors of patients with breast cancer demonstrates relationship of expression of MUC I with inflammation and its modulation by T-regulative cells. The effect of expression of analyzed genes on phenotype of cancer cells and course of disease are discussed.

Genetic Instability in Locus rs5498 E469K (A/G) of ICAM-1 Gene in Patients with Colorectal Cancer and Breast Cancer

Single-nucleotide polymorphism rs5498 E469K (A/G) in ICAM-1 gene modulates functional activity of this protein and is associated with the risk of some diseases. Tumor cell rs5498 E469K (A/G) genotypes were compared with genotypes of patients with colorectal and breast cancer, residents of the Nizhniy Novgorod region. Specimens of peripheral blood and tumor foci from patients with colorectal and breast cancer and peripheral blood specimens from normal subjects were analyzed. The frequency of genotypes of single-nucleotide rs5498 E469K (A/G) sequence in the Nizhny Novgorod population coincide with the frequency of genotypes characteristic of residents of Germany. Comparison of genotypes of peripheral blood and tumor cells from patients with colorectal and breast cancer showed loss of cancer cell heterozygosity. The frequency of heterozygosity loss increases with colorectal cancer progress from one stage to another.

[Role of MUC1 Expression in Tumor Progression]

Mucin 1 (MUC1) is a multistructural and multifunctional protein that is involved in regulating diverse cellular activities. This strongly glycosylated transmembrane protein forms a mucous gel on the surface of epithelial cells that protects the cells from injury. MUC1 acts as a signaling molecule and transcription factor modulating metabolism and resistance to bacterial-induced inflammation. This article presents a review of the relationship between structural and functional changes of the MUC1 and the characteristics of cancer cells. The alteration in MUC1 expression level, a number of structural forms, protein glycosylation and localization occurs in cancer cells. These alterations lead to metabolic reprogramming associated with proliferation, resistance to hypoxia and angiogenesis which affects the survival of cancer cells. Furthermore, cancer cells can take advantage of MUC1 interaction with adhesion molecules for invasion and metastasis. Thus, MUC1 plays a key role both in the homeostasis of epithelial cells and in cancer progression. Understanding the role of MUC1 expression in tumor cells survival is important for the development of new monitoring and therapeutic approaches for the treatment MUC1 positive maligancies.

Levocarnitine normalizes elevated blood level of soluble Fas mRNA in patients with acute myocardial infarction

Fas-induced apoptosis plays an important role in the mechanisms of tissue injury in myocardial infarction. The level of membrane Fas mRNA was elevated during the postinfarction period in the blood of patients and did not change in response to levocarnitine. The mRNA level of soluble Fas, inhibiting Fas-dependent apoptosis, remained normal during the first 7 days, but increased 14 days after myocardial infarction, which corresponded to previously detected increase of serum level of soluble Fas molecules. Addition of levocarnitine, inhibiting Fas-dependent apoptosis, to therapy caused no changes in the level of soluble Fas mRNA, presumably because of similar effects of soluble Fas and levocarnitine on the apoptotic processes in myocardial infarction.

[Early detection of cancer/testis mRNAs in tumor cells circulating in the peripheral blood of colorectal cancer patients]

Recent studies have suggested that mRNAs transcribed from cancer/testis genes might be used as biomarkers of cancer cells migrating through the bloodstream. Using RT-PCR we evaluated the expression of several cancer/testis mRNAs (MAGEA1-6, GAGE1-8, NY-ESO-1, SSX1, 2, and 4, XAGE1 and MAGEC1) in primary tumors and peripheral blood samples of colorectal cancer patients. The detection rate of at least one of the transcripts was 95% (37/39 samples) for primary tumors and 81% (52/64 samples) for the peripheral blood. Moreover, selected mRNAs were detectable in cellular fraction of the peripheral blood at all stages the disease (14 out of 14 cases), whereas in extracellular fraction of plasma were found only at stages III and IV. Obtained data open a possibility of early diagnosis of colorectal cancer in people at high risk by peripheral blood analysis.

[Heterogeneous expression of CD38 gene in tumor tissue in patients with colorectal cancer]

The CD38 gene codes a membrane protein which takes part in cell adhesion and catalyzes the formation of cyclic ADP-ribose. Using RT-PCR method we tested the presence of full-size and alternative forms of mRNA CD38 in samples of tumor tissue of patients with colorectal cancer and in tumor cell lines. It was shown that there are the cells in the tumor tissue which expressed CD38 gene. In tumor tissue of patients the alternative form of mRNA CD38 was detected less frequently than full-size form. Cells of lines Colo-205, T-84, HCT15 and HCT116 contained mRNA CD38, in cells of lines Caco-2 and SW-620 mRNA CD38 was absent. In cells of tumor tissue on the first stage of colorectal cancer CD38 gene was expressed in 100% of cases. On the second, third and fourth stages of the disease gene expression was observed less often. The frequency of mRNA CD38 detection not depend on tumor localization, tumor grade and presence of metastases. Using method of restriction analysis CpG methylation was detected in binding sites of transcription factor Sp1 and receptor of retinoic acid (RARE) in all tested samples of tumor tissue independently of the presence or absence of mRNA CD38. The obtained data suggest that in the tumor cells of patients with colorectal cancer the expression of the CD38 gene is heterogeneous.

Fluorescence detection of white-beam X-ray absorption anisotropy: towards element-sensitive projections of local atomic structure

Projections of the atomic structure around Nb atoms in a LiNbO(3) single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples.

Study of DNA interaction with cobalt ferrite nanoparticles

Interaction of cobalt ferrite nanopowder and nucleic acid was investigated. Superparamagnetic cobalt ferrite nanoparticles (6-12 nm) were prepared by mechanochemical synthesis. Structure of the nanopowder was characterized using X-ray diffraction. It was shown that cobalt ferrite nanoparticles were associated with ssDNA and dsDNA in Tris-buffer resulting in bionanocomposite formation with mass weight relation nanoparticles: DNA 1:(0.083 +/- 0.003) and 1:(0.075 +/- 0.003) respectively. The mechanism of interaction between a DNA and cobalt ferrite nanoparticles was considered basing on the whole set of obtained data: FTIR-spectroscopy, analyzing desorption of DNA from the surface of the particles while changing the chemical content of the medium, and on the modeling interaction of specific biomolecule fragments with surface of a inorganic material. It was supposed that the linkage was based on coordination interaction of the phosphate groups and oxygen atoms heterocyclic bases of DNA with metal ions on the particle surface. These data can be used to design specific magnetic DNA-nanoparticles hybrid structures.

[Genetic diversity of human caliciviruses detected in schoolchildren with gastroenteritis in Nizhni Novgorod]

A total of 2312 children admitted to the Nizhni Novgorod infectious disease hospitals for diagnosed acute gastroenteritis were examined using the RT-PCR. The detection rate of human caliciviruses was found to be 6.5% (range 1.2 to 11.2%). The population of calicivuruses presented with noroviruses genogroups I (16%) and II (81%), and sapoviruses (3%). Noroviruses genogroup II included genotypes GII.2 and GII.4 with a preponderance of the variant CII.4-2006b. The detected sapoviruses were clustered with sapoviruses GI.1, GI.2, and GII.1 by phylogenetic analysis.

[Detection rate of MAGE-A1-A6 mRNA in the peripheral blood of cancer patients]

The mRNA expression of 6 MAGE-A (MAGE-A1-A6) antigens by the tumor focal cells and cancer cells circulating in blood was studied in solid malignant and benign neoplasms. MAGE- A1-A6 mRNA expression was detected in the tumor focal cells in more than 90% of cases of cancer of the breast, lung, and stomach and melanoma cell lines. The detection rate of peripheral blood MAGE-A1-A6-positive tumor cells was 95% in lung cancer, 53% in corpus uteri cancer, 67% in gastric cancer, 63% in breast cancer, 33% in melanoma, and 42% in uterine myoma. MAGE-A3 and MAGE-A4 mRNA expression was more commonly observed.

[Aseptic meningitis season caused by enteroviruses in 2007: molecular-epidemiological aspects]

AIM

Analysis of manifestation of epidemic process of aseptic meningitis and causes of its activation using molecular genetic methods.

MATERIALS AND METHODS

Samples of feces and CSF, nasopharyngeal swabs from 296 patients with aseptic meningitis (AM), as well as 240 samples of drinking water and 6 samples of lake water were studied. Epidemiologic analysis, isolation of enteroviruses in Hep-2 and RD cell cultures, RT-PCR, partial sequencing of 5'NTR and genome region coding VP1 were performed.

RESULTS

Marked rise of AM caused by enteroviruses in Nizhny Novgorod during 2001 - 2007 was demonstrated. From August to October 2007, enteroviruses were detected in 93.8% of patients with AM (22.5 per thousand). Seasonal rise of incidence was determined by 9 serotypes of enteroviruses: E30 - 26 cases (53.1%), E7 - 7 (14.3%), E18 - 5 (10.3%), E13 - 3 (6.1%), E9 - 2 (4.0%), CB5 - 3 (6.1%),CA1 - 1 (2.0%), CA9 - 1 (2.0%), CA13 - 1 (2.0%). Serotype E30, represented by two subtypes, dominated. Dominating subtype E30-N1 was closely related with E30 strains isolated in 1994 - 2001 in Europe. Subtype E30-N2 was genetically related with Asian strains isolated in 2000 - 2006. RNA of E7, E9, E13, E18, CB5 viruses and dominating subtype E30-N1 were detected in nasopharyngeal swabs from patients with AM, which can explain rapid and wide spread of these viruses in susceptible population by aspiration route of transmission.

CONCLUSION

Increased incidence of AM in Nizhny Novgorod in 2007 was caused by variant of E30 virus, which was genetically related with strains isolated in European countries in 1997.

[Nucleotide sequence analysis of the NSP4 gene from group A rotaviruses isolated in Nizhni Novgorod]

The complete nucleotide sequences of the NSP4 gene from Russian isolates of Group A rotaviruses with different G[P] types obtained in Nizhni Novgorod have been first ascertained. They belong to their affiliation to three NSP4 (A, B, and C) of the 5 known genotypes. Eleven strains had NSP4 genotype. Phylogenetic analysis based on the complete nucleotide sequences of the NSP4 gene revealed the sequence homology of G1P[8] viruses with the strains circulating in Scandinavia and that of the G3 type viruses with the strains from South-Eastern Asia. The rotavirus strains G1, G3, G4, and P[8] demonstrated the homology with porcine rotavirus strains, while the strains G3P[6], G3P[9], and G2P[4] did the homology with bovine rotavirus strains. There was an unusual strain of human rotaviruses G3P[9] genetically related to feline rotaviruses.

Novel variant of tickborne encephalitis virus, Russia

We isolated a novel strain of tickborne encephalitis virus (TBEV), Glubinnoe/2004, from a patient with a fatal case in Russia. We sequenced the strain, whose landmark features included 57 amino acid substitutions and 5 modified cleavage sites. Phylogenetically, Glubinnoe/2004 is a novel variant that belongs to the Eastern type of TBEV.

[Phenotropil use as premedication during out-patient stomatological treatment]

Clinical and pharmacological characteristics of phenotropil were given. Its efficiency in premedication of patients with different individually typological features during out-patient treatment was shown. Also its neurotropic effect and influence on some psychophysiological and hemodinamical indices were studied.

X-ray tomographic imaging of crystal structure at the atomic level

A direct nondiffractive tomographic algorithm is proposed for the determination of the crystal structure from real-space projections obtained by illuminating the sample with white x rays. This approach was applied to the pattern of the directional fine structure in absorption of white x rays recorded for a GaP crystal and allowed for a determination of the electron density distribution within the unit cell.

[Choice criteria of premedication in outpatient stomatologic department]

We have analyzed factors causing stress during out-patient dental treatment. The psychological characteristic of people with prevalence of sthenical and asthenical features were given and dependence of the effect of the medicine on individual features was shown.

[Serum level of soluble forms of membranous antigens of immune system cells in carriers of virus hepatitis G markers]

The levels of soluble CD38 (sCD38), CD50 (sCD50), and CD95 (sCD95) antigens and HLA class I (sHLA-I) were determined in the serum samples from persons infected with hepatitis G virus (HGV). HGV monoinfection was accompanied by a rise in the serum content of sCD38, sCD50, and sCD95 antigens. The serum presence of HGV RNA and anti-E2 HGV antibodies was characterized by the normal content of sCD38 and sCD95 while the level of sCD50 was elevated and the serum content of sHLA-I was decreased. If the serum contained only anti-E2 HGV antibodies, the level of sCD50 remained increased 4-fold. It is suggested that the higher adhesion-inhibiting level of sCD50 is a reason of a weak immune response to HGV and hence of a long HGV persistence in the body.

[Production of full length DNA copies of genomic segments of influenza virus using DNA recombination in the process of polymerase chain reaction]

The case study comprises a description of a method used for producing the full-length cDNA complementary to influenza virus segments made through the recombination of homologous DNA fragments in the process of polymerase chain reaction (PCR). The detailed protocol of the method is presented alongside with a discussion of the advantages of the suggested approach.

[Assessment of a developed "nested" variant of polymerase chain reaction for detecting enteroviruses in patients]

The RT-PCR assay for the detection of all human enteroviruses was used to analyze fecal samples, cerebrospinal fluid (CSF), respiratory tract swabs, and sera from 204 patients with symptoms of viral infection. Enteroviruses were detected in 31.37% of cases. The proposed method analyzes every type of clinical samples. The relative detection rate of enteroviruses in different samples was 70.64% in feces, 10.4% in SCF, 17.24% in swabs, and 21.14% in the sera. The use of serum in addition to other testing samples increased the rate of enterovirus detection at 18.25%. Developing techniques may be used for the diagnosis of acute enterovirus infections with different clinical manifestations.

[Genome analysis of hepatitis C virus strain 274933RU isolated in Russian Federation]

Five overlapping cDNA fragments of hepatitis C virus (HCV) isolate 274933RU, obtained by RT-PCR, were amplified and cloned. Complete nucleotide RNA sequence has been determined. The genomic organization of 274933RU was, from 5' to 3' terminals, 5' UTR (341 nt), polyprotein ORF (9033 nt), 3' UTR (40 nt except for the poly(U-UC) and polypyrimidine stretch), and X-tail (98 nt). Phylogenetic analysis of the core and NS5 genes showed that the isolated strain belonged to HCV 1b subtype.

[Genetic analysis of West Nile fever virus, isolated in the south of the Russian plain (Volgograd and Astrakhan regions) in 1999]

Two strains of West Nile virus, Vlg 27889 and Ast 986, were isolated from the brain of a dead man and from the blood of a patient, respectively, during an outbreak of serous meningitis and meningoencephalitis in July-September, 1999, in the Volgograd and Astrakhan regions. Analysis of parts of genome of the strains cloned from cell culture by reverse transcription and polymerase chain reaction demonstrated their identity and appurtenance to group I West Nile viruses.

[Determination of hepatitis G virus markers in various risk groups]

Study of prevalence of hepatitis G virus (HGV) markers in different risk groups showed the presence of HGV RNA in 3.2% blood donors, 24.2% patients with hepatitis C (HCV), and 28% patients with hemophilia. HGV antibodies were detected in 11.3% donors, 16.0% patients with HCV, 13.4% patients with hemophilia, and 8.5% HIV-infected subjects. Anti-E1 HGV were more often detected in the absence of HGV RNA. Antibodies to HGV E2 protein were significantly more often detected in adult HCV patients but not in adolescent patients aged 8-15 years.

Parametric down conversion of X-ray photons

Parametric down conversion of X-ray photons in diamond crystals was detected in two experiments, both using the phase-matching scheme first employed in the X-ray regime by Eisenberger & McCall [Phys. Rev. Lett. (1971), 26, 684-688]. The conversion events were detected by a combination of time-correlation spectroscopy and energy discrimination, using Si drift-chamber detectors. The time-correlation spectra give a direct comparison of the conversion rate over the accidental coincidence rate. Mechanisms for possible detection of false events and ways to cross check against them are discussed in detail.

[Comparative analysis of fragments of HGV NS5b-region isolated in Russia, Kazakhstan and Kyrgyztan]

Nucleotide sequence of a 356 nt fragment of the NS5 region of the hepatitis G virus (HGV) genome was determined in 7 strains isolated in Russia, Kazakhstan, and Kyrghyzstan. Philogenetic analysis showed that all isolated strains genetically differed from the West African strain described previously (type 1) and are closely related to strains isolated in the USA and South-Eastern Asia (type 2). Hence, the strains from Russia, Kazakhstan, and Kyrghyzstan belong to type 2 variant of HGV genome.

X-ray Holography for Structural Imaging

X-ray atomic resolution holography is a new method for direct evaluation of three-dimensional electron density distribution in solids. The practical implementation of the multiple-energy technique on a synchrotron radiation source as well as image reconstruction from the experimental data are described. Holograms at several different energies were processed together to suppress twin images and artifacts from long-range-order effects in the experimental data sets. Reconstructed images of copper atoms in Cu(2)O crystals are presented.