Exome Sequencing: the Search for Mutations Associated with Hereditary Breast and Ovarian Cancers in the Tuvan Ethnic Group (A Pilot Study).

Whole exome sequencing of peripheral blood samples from Tuvan females diagnosed with breast and ovarian cancers (BC/OC) was performed to search for new genes involved in BC/OC pathogenesis. Considering the high cost of whole exome sequencing and study material requirements, 9 samples were selected from 61 genomic DNA samples. A mutation in the LGR4 gene (rs34804482) involved in the tumor-mediated Wnt signaling pathway and a mutation in the BRWD1 gene (rs147211854) involved in chromatin remodeling were identified in BC patients. A mutation in the CITED2 gene (rs77963348) involved in the pathogenesis of primary ovarian insufficiency was identified in a patient with OC and a history of infertility. A mutation in the PDGFRA gene (rs2291591) was identified in two BC/OC patients. LRG4, BRWD1, PDGFRA, and CITED2 germline pathogenic mutations were discovered in Tuvan women diagnosed with BC/OC for the first time.

[Methylation of Regulatory Regions of DNA Repair Genes in Carotid Atherosclerosis].

The status of DNA methylation in the human genome changes during the pathogenesis of common diseases and acts as a predictor of life expectancy. Therefore, it is of interest to investigate the methylation level of regulatory regions of genes responsible for general biological processes that are potentially significant for the development of age-associated diseases. Among them there are genes encoding proteins of DNA repair system, which are characterized by pleiotropic effects. Here, results of the targeted methylation analysis of two regions of the human genome (the promoter of the MLH1 gene and the enhancer near the ATM gene) in different tissues of patients with carotid atherosclerosis are present. Analysis of the methylation profiles of studied genes in various tissues of the same individuals demonstrated marked differences between leukocytes and tissues of the vascular wall. Differences in methylation levels between normal and atherosclerotic tissues of the carotid arteries were revealed only for two studied CpG sites (chr11:108089866 and chr11:108090020, GRCh37/hg19 assembly) in the ATM gene. Based on this, we can assume the involvement of ATM in the development of atherosclerosis. "Overload" of the studied regions with transcription factor binding sites (according to ReMapp2022 data) indicate that the tissue-specific nature of methylation of the regulatory regions of the MLH1 and ATM may be associated with expression levels of these genes in a particular tissue. It has been shown that inter-individual differences in the methylation levels of CpG sites are associated with sufficiently distant nucleotide substitutions.

DNA methylome analysis reveals potential alterations contributing to the progression of bronchial hyperplasia.

BACKGROUND: Squamous cell lung cancer (SCLC) arises from bronchial changes: basal cell hyperplasia (BCH), squamous metaplasia (SM), and dysplasia. However, the premalignant process preceding SCLC is not inevitable; it can stop at any of the bronchial lesions. Previously, we hypothesized that combinations of premalignant lesions observed in the small bronchi of SCLC patients can reflect the different "scenarios" of the premalignant process: BCHi-the stoppage at the stage of hyperplasia and BCHSM-the progression of hyperplasia to metaplasia. METHODS AND RESULTS: In this study, using whole-genome bisulfite sequencing we analyzed the DNA methylome of two forms of BCH: isolated BCH (BCHi) and BCH co-occurred with SM (BCHSM) in the small bronchi of SCLC patients. It was shown that BCHi harbored differentially methylated regions (DMRs) affecting genes associated with regulating phosphatase activity. In BCHSM, DMRs were found in genes involved in PI3K-Akt and AMPK signaling pathways. DMRs were also found to affect specific miRNA genes: miR-34a and miR-3648 in BCHi and miR-924 and miR-100 in BCHSM. CONCLUSIONS: Thus, this study demonstrated the significant changes in DNA methylome between the isolated BCH and BCH combined with SM. The identified epigenetic alterations may underlie different "scenarios" of the premalignant process in the bronchial epithelium.

[Identification of Functionally Significant Polymorphic Variants in miRNA Genes in Carotid Atherosclerosis].

miRNAs are vital molecules of gene expression. They are involved in the pathogenesis of various common diseases, including atherosclerosis, its risk factors, and its complications. A detailed characterization of the spectrum of functionally significant polymorphisms of miRNA genes in patients with advanced carotid atherosclerosis is an important research task. We analyzed miRNA expression and exome sequencing data of carotid atherosclerotic plaques of male patients (n = 8, 66-71 years of age, 67-90% degree of carotid artery stenosis). For further study and analysis of the association between the rs2910164 polymorphism of the MIR146A gene and advanced carotid atherosclerosis, we recruited 112 patients and 72 relatively healthy Slavic residents of Western Siberia. A total of 321 and 97 single nucleotide variants (SNVs) were detected in the nucleotide sequences of pre- and mature miRNAs in carotid atherosclerotic plaques. These variants were located in 206 and 76 miRNA genes, respectively. Integration of the data of exome sequencing and miRNA expression revealed 24 SNVs of 18 miRNA genes that were processed to mature form in carotid atherosclerotic plaques. SNVs with the greatest potential functional significance for miRNA expression predicted in silico were rs2910164:C>G (MIR146A), rs2682818:A>C (MIR618), rs3746444:A>G (MIR499A), rs776722712:C>T (MIR186), rs199822597:G>A (MIR363). The expression of miR-618 was lower in carotid atherosclerotic plaques of patients with the AC rs2682818 genotype of the MIR618 gene compared with the CC genotype (log2FC = 4.8; p = 0.012). We also found an association of rs2910164:C (MIR146A) with the risk of advanced carotid atherosclerosis (OR = 2.35; 95% CI: 1.43-3.85; p = 0.001). Integrative analysis of polymorphisms in miRNA genes and miRNA expression is informative for identifying functionally significant polymorphisms in miRNA genes. The rs2682818:A>C (MIR618) is a candidate for regulating miRNA expression in carotid atherosclerotic plaques. The rs2910164:C (MIR146A) is associated with the risk of advanced carotid atherosclerosis.

Relationship of the gene pool of the Khants with the peoples of Western Siberia, Cis-Urals and the Altai-Sayan Region according to the data on the polymorphism of autosomic locus and the Y-chromosome.

Khanty are indigenous Siberian people living on the territory of Western Siberia, mainly on the territory of the Khanty-Mansiysk and Yamalo-Nenets Autonomous Okrugs. The present study is aimed at a comprehensive analysis of the structure of the Khanty gene pool and their comparison with other populations of the indigenous population of Southern and Western Siberia. To address the issues of genetic proximity of the Khanty with other indigenous peoples, we performed genotyping of a wide genomic set of autosomal markers using high-density biochips, as well as an expanded set of SNP and STR markers of the Y-chromosome in various ethnic groups: Khakas, Tuvans, Southern Altaians, Siberian Tatars, Chulyms (Turkic language family) and Kets (Yeniseian language family). The structure of the gene pool of the Khanty and other West Siberian and South Siberian populations was studied using a genome-wide panel of autosomal single nucleotide polymorphic markers and Y-chromosome markers. The results of the analysis of autosomal SNPs frequencies by various methods, the similarities in the composition of the Y-chromosome haplogroups and YSTR haplotypes indicate that the Khanty gene pool is quite specific. When analyzing autosomal SNPs, the Ugrian genetic component completely dominates in both samples (up to 99-100 %). The samples of the Khanty showed the maximum match in IBD blocks with each other, with a sample of the Kets, Chulyms, Tuvans, Tomsk Tatars, Khakas, Kachins, and Southern Altaians. The degree of coincidence of IBD blocks between the Khanty, Kets, and Tomsk Tatars is consistent with the results of the distribution of allele frequencies and common genetic components in these populations. According to the composition of the Y-chromosome haplogroups, the two samples of the Khanty differ significantly from each other. A detailed phylogenetic analysis of various Y-chromosome haplogroups made it possible to describe and clarify the differences in the phylogeny and structure of individual ethnospecific sublines, to determine their relationship, traces of population expansion in the Khanty gene pool. Variants of different haplogroups of the Y-chromosome in the Khanty, Khakas and Tuvans go back to their common ancestral lines. The results of a comparative analysis of male samples indicate a close genetic relationship between the Khanty and Nenets, Komi, Udmurts and Kets. The specificity of haplotypes, the discovery of various terminal SNPs confirms that the Khanty did not come into contact with other ethnic groups for a long time, except for the Nenets, which included many Khanty clans.

Changes in DNA methylation profile in liver tissue during progression of HCV-induced fibrosis to hepatocellular carcinoma.

In this study we compared methylation levels of 27,578 CpG sites between paired samples of the tumor and surrounding liver tissues with various degrees of damage (fibrosis, cirrhosis) in HCV-induced hepatocellular carcinoma (HCC) patients, as well as between tumor and normal tissue in non-viral HCC patients, using GSE73003 and GSE37988 data from GEODataSets (https://www.ncbi.nlm.nih.gov/). A significantly lower number of differentially methylated sites (DMS) were found between HCC of non-viral etiology and normal liver tissue, as well as between HCC and fibrosis (32 and 40), than between HCC and cirrhosis (2450 and 2304, respectively, according to GSE73003 and GSE37988 datasets). As the pathological changes in the tissue surrounding the tumor progress, the ratio of hyper-/hypomethylated DMSs in the tumor decreases. Thus, in tumor tissues compared with normal/fibrosis/cirrhosis of the liver, 75/62.5/47.7 % (GSE73003) and 16 % (GSE37988) of CpG sites are hypermethylated, respectively. Persistent hypermethylation of the ZNF154 and ZNF540 genes, as well as CCL20 hypomethylation, were registered in tumor tissue in relation to both liver fibrosis and liver cirrhosis. Protein products of the EDG4, CCL20, GPR109A, and GRM8 genes, whose CpG sites are characterized by changes in DNA methylation level in tumor tissue in the setting of cirrhosis and fibrosis, belong to "Signaling by G-protein-coupled receptors (GPCRs)" category. However, changes in the methylation level of the "driver" genes for oncopathology (АРС, CDKN2B, GSTP1, ELF4, TERT, WT1) are registered in tumor tissue in the setting of liver cirrhosis but not fibrosis. Among the genes hypermethylated in tumor tissue in the setting of liver cirrhosis, the most represented biological pathways are developmental processes, cell-cell signaling, transcription regulation, Wnt-protein binding. Genes hypomethylated in liver tumor tissue in the setting of liver cirrhosis are related to olfactory signal transduction, neuroactive ligand-receptor interaction, keratinization, immune response, inhibition of serine proteases, and zinc metabolism. The genes hypermethylated in the tumor are located at the 7p15.2 locus in the HOXA cluster region, and the hypomethylated CpG sites occupy extended regions of the genome in the gene clusters of olfactory receptors (11p15.4), keratin and keratin-associated proteins (12q13.13, 17q21.2, and 21q22.11), epidermal differentiation complex (1q21.3), and immune system function loci 9p21.3 (IFNA, IFNB1, IFNW1 cluster) and 19q13.41-19q13.42 (KLK, SIGLEC, LILR, KIR clusters). Among the genes of fibrogenesis or DNA repair, cg14143055 (ADAMDEC1) is located in the binding region of the HOX gene family transcription factors (TFs), while cg05921699 (CD79A), cg06196379 (TREM1) and cg10990993 (MLH1) are located in the binding region of the ZNF protein family transcription factor (TF). Thus, the DNA methylation profile in the liver in HCV-induced HCC is unique and differs depending on the degree of surrounding tissue lesion - liver fibrosis or liver cirrhosis.

Structure and origin of Tuvan gene pool according to autosome SNP and Y-chromosome haplogroups.

Tuvans are one of the most compactly living peoples of Southern Siberia, settled mainly in the territory of Tuva. The gene pool of the Tuvans is quite isolated, due to endogamy and a very low frequency of interethnic marriages. The structure of the gene pool of the Tuvans and other Siberian populations was studied using a genome-wide panel of autosomal single nucleotide polymorphic markers and Y-chromosome markers. The results of the analysis of the frequencies of autosomal SNPs by various methods, the similarities in the composition of the Y-chromosome haplogroups and YSTR haplotypes show that the gene pool of the Tuvans is very heterogeneous in terms of the composition of genetic components. It includes the ancient autochthonous Yeniseian component, which dominates among the Chulym Turks and Kets, the East Siberian component, which prevails among the Yakuts and Evenks, and the Far Eastern component, the frequency of which is maximum among the Nivkhs and Udeges. Analysis of the composition of IBD-blocks on autosomes shows the maximum genetic relationship of the Tuvans with the Southern Altaians, Khakas and Shors, who were formed during the settlement of the Turkic groups of populations on the territory of the Altai-Sayan region. A very diverse composition of the Tuvan gene pool is shown for various sublines of Y-chromosomal haplogroups, most of which show strong ethnic specificity. Phylogenetic analysis of individual Y-chromosome haplogroups demonstrates the maximum proximity of the gene pool of the Tuvans with the Altaians, Khakas and Shors. Differences in frequencies of Y-chromosome haplogroups between the Todzhans and Tuvans and a change in the frequencies of haplogroups from south to north associated with the East Asian component were found. The majority of the most frequent Y-chromosome haplogroups in the Tuvans demonstrate the founder effect, the formation age of which is fully consistent with the data on their ethnogenesis.

Blocks identical by descent in the genomes of the indigenous population of Siberia demonstrate genetic links between populations.

The gene pool of the indigenous population of Siberia is a unique system for studying population and evolutionary genetic processes, analyzing genetic diversity, and reconstructing the genetic history of populations. High ethnic diversity is a feature of Siberia, as one of the regions of the peripheral settlement of modern human. The vast expanses of this region and the small number of aboriginal populations contributed to the formation of significant territorial and genetic subdivision. About 40 indigenous peoples are settled on the territory of the Siberian historical and ethnographic province. Within the framework of this work, a large-scale population study of the gene pool of the indigenous peoples of Siberia was carried out for the first time at the level of high-density biochips. This makes it possible to fill in a significant gap in the genogeographic picture of the Eurasian population. For this, DNA fragments were analyzed, which had been inherited without recombination by each pair of individuals from their recent common ancestor, that is, segments (blocks) identical by descent (IBD). The distribution of IBD blocks in the populations of Siberia is in good agreement with the geographical proximity of the populations and their linguistic affiliation. Among the Siberian populations, the Chukchi, Koryaks, and Nivkhs form a separate cluster from the main Siberian group, with the Chukchi and Koryaks being more closely related. Separate subclusters of Evenks and Yakuts, Kets and Chulyms are formed within the Siberian cluster. Analysis of SNPs that fell into more IBD segments of the analyzed populations made it possible to compile a list of 5358 genes. According to the calculation results, biological processes enriched with these genes are associated with the detection of a chemical stimulus involved in the sensory perception of smell. Enriched for the genes found, molecular pathways are associated with the metabolism of linoleic, arachidonic, tyrosic acids and by olfactory transduction. At the same time, an analysis of the literature data showed that some of the selected genes, which were found in a larger number of IBD blocks in several populations at once, can play a role in genetic adaptation to environmental factors.

Analysis of mutations spectrum in the ATP7B gene in patients with Wilson disease using massively parallel sequencing.

The study aimed to search for mutations in the ATP7B gene using massively parallel sequencing in patients with Wilson disease in the Tomsk region. For 42 patients with suspected Wilson's disease (aged from 1 to 33 years) was performed molecular genetic analysis. Enrichment of the interest genome regions was carried out by the long-range PCR. DNA libraries with ligated adapters were constructed with Nextera DNA Flex (Illumina, USA) kit. Sequencing was performed on the Illumina MiSeq platform (Illumina, USA). As a result of this work, we identified 9 pathogenic genetic variants. All variants were previously described in the literature and were found in patients with Wilson's disease. Five missense mutations, one splice site mutation, and 3 frameshift mutations were identified. In patients with Wilson's disease in the Tomsk region, the most common variant was c.3207C>A, this variant is the most common both in the Russian Federation and in other European populations. Also, a pathogenic variant c.3036dupC was found, which is probably endemic to the Russian Federation.

MicroRNAs as the Potential Regulators of SARS-CoV-2 Infection and Modifiers of the COVID-19 Clinical Features.

The pandemic of coronavirus disease 2019 (COVID-19) warrants the identification of factors that may determine both risk and severity of infection. The factors include microRNAs that have a wide regulatory potential and hence are particularly interesting. The review focuses on the potential roles of human microRNAs and the viral genome as well as microRNAs in SARS-CoV-2 infection and clinical features of COVID-19. The review summarizes the information about the human microRNAs that are thought to specifically bind to the SARS-CoV-2 genome and considers their expression levels in various organs (cells) in both healthy state and pathologies that are risk factors for severe COVID-19. Potential mechanisms whereby SARS-CoV-2 may affect the clinical features of COVID-19 are discussed in brief. The mechanisms include blocking of human microRNAs and RNA-binding proteins, changes in gene expression in infected cells, and possible epigenetic modifications of the human genome with the participation of coronavirus microRNAs. Supplementary Information: The online version contains supplementary material available at 10.1134/S0026893322010034.

[miRNA Regulome in Different Atherosclerosis Phenotypes].

Dysregulation of microRNA (miRNA) expression is associated with a susceptibility to many diseases, including atherosclerotic lesions of the coronary and carotid arteries and the development of clinical complications such as coronary heart disease, myocardial infarction, chronic cerebral ischemia, ischemic stroke. Recently, more and more studies analyze the miRNA regulome including a network of regulatory elements for the expression of miRNAs themselves and targets under their control. The review summarizes the data from articles concerned miRNA expression and changes in DNA methylation in the miRNA genes in human atherosclerotic arteries, as well as with the analysis of the association between single nucleotide polymorphisms and copy number variations in the miRNA genes with clinical complications of atherosclerosis.

[Protocol of Transcriptome Analysis of Decidual Placenta Cells].

The advent of high-throughput sequencing technologies has expanded our understanding of the biological significance of non-coding regions of the genome. In recent years, more and more studies have been devoted to studying the role of noncoding RNAs in the development of diseases, as well as their participation in various cellular processes. Until now, all transcriptome studies of native placental tissue with the description of the noncoding RNA region were carried out without isolating individual cell populations. This approach, due to the high cellular heterogeneity of the placental tissue, significantly complicates the ability to determine the molecular-biological functions of individual cells and their role in the molecular pathogenesis of reproductive disorders. In this work, we propose a technique for obtaining total RNA from single decidual cells of frozen placental tissue obtained by laser-capture microdissection technology for transcriptome sequencing, including a cluster of noncoding RNAs. This technique can be successfully used to study the full-genome expression profile of other placental cell populations. The high accuracy of results on the transcriptome profiling of decidual cells obtained using the developed technique was additionally confirmed by an integrative analysis with the results of a 10x Genomics experiment.

[MicroRNAs as the Potential Regulators of SARS-CoV-2 Infection and Modifiers of the COVID-19 Clinical Features].

The pandemic of coronavirus disease 2019 (COVID-19) warrants the identification of factors that may determine both risk and severity of infection. The factors include micro RNAs that have a wide regulatory potential and hence are particularly interesting. The review focuses on the potential roles of human microRNAs and the viral genome as well as microRNAs in SARS-CoV-2 infection and clinical features of COVID-19. The review summarizes the information about the human microRNAs that are thought to specifically bind to the SARS-CoV-2 genome and considers their expression levels in various organs (cells) in both healthy state and pathologies that are risk factors for severe COVID-19. Potential mechanisms whereby SARS-CoV-2 may affect the clinical features of COVID-19 are discussed in brief. The mechanisms include blocking of human microRNAs and RNA-binding proteins, changes in gene expression in infected cells, and possible epigenetic modifications of the human genome with the participation of coronavirus microRNAs.

Generation of an induced pluripotent stem cell line ICGi030-A from a Wilson's disease patient carrying a frameshift mutation p.Lys1013fs and missense mutation p.H1069Q in the ATP7B gene.

Wilson's disease is a rare autosomal recessive disorder of copper metabolism. The copper accumulation in the viscera appears due to the functional impairment of copper-transporting ATPase, which is encoded by the ATP7B gene. In this study, PBMCs of a patient with two ATP7B mutations were reprogrammed. The first mutation is a missense mutation p.H1069Q, which is the most frequent mutation in the human population. At the same time, the second one is a frameshift mutation p.Lys1013fs. The generated iPSC line had a normal karyotype, maintained the original genotype, expressed pluripotency markers, and demonstrated the ability to differentiate into derivatives of the three germ layers.

[Comparative analysis of gene expression in vascular cells of patients with advanced atherosclerosis]. / Sravnitel'nyi analiz ékspressii genov v kletkakh sosudov u bol'nykh s klinicheski vyrazhennym aterosklerozom.

In this study we performed a comparative gene expression analysis of carotid arteries in the area of atherosclerotic plaques and healthy internal mammary arteries of patients with advanced atherosclerosis by using microarray HumanHT-12 BeadChip ("Illumina"). The most down-regulated genes were APOD, FABP4, CIDEC and FOSB, and up-regulated gene was SPP1 (|FC|>64; pFDR<0.05). The majority of differentially expressed genes were down-regulated in advanced atherosclerotic plaques. Unexpectedly, genes involved in immune and inflammatory responses were down-regulated in advanced atherosclerotic plaques to compare with the healthy arteries (arachidonic acid metabolism, cytokine-cytokine receptor interaction, NOD-like receptor signaling pathway, Jak-STAT signaling pathway, TNF signaling pathway). "Cellular response to metal ion" (metallothioneins) and "Extracellular matrix organization" were the most significant Gene ontology terms among the down- and up-regulated genes, respectively.

[The effect of controllable moderate hypothermia on hemostasis in newborns with hypoxemic ischemic encephalopathy.]

THE PURPOSE: To study effect of controllable moderate hypothermia on system of hemostasis in newborns with hypoxemic ischemic encephalopathy. MATERIALS AND METHODS: The retrospective analysis was carried out concerning 38 medical records of newborns with acute hypoxia of fetus (group I), 12 medical records of newborns with acute hypoxia of fetus against the background of chronic hypoxia of fetus (group II), 20 healthy newborns (group III) and 20 healthy adults. The thromboelastography was implemented in three stages: at first, third and sixth days of life of newborns. CONCLUSION: The thromboelastography is to be implemented in newborns with hypoxemic ischemic encephalopathy due to occurrence of of hemostasis shifting to hypocoagulation and high risk of bleeding. In healthy full-term children a physiological hypercoagulation was established as compared with adults without alterations of processes of lysis of clots. In newborns with chronic hypoxia of fetus against the background of applied medical hypothermia, in comparison with healthy newborns, decreasing of number of thrombocytes are observed and possibly lower functional activity of thrombocytes up to third day and also lower activity of plasma component of hemostasis at retained elasticity and strength of developed clots. The sixth day, after heating, the system of hemostasis is normalized and number of thrombocytes is restored. In newborns, having acute hypoxia of fetus against the background of chronic hypoxia of fetus higher risk of bleeding is noted at minimal difference according results of thromboelastography.

[TREATMENT OF SEVERE INTRAPATUM ASPHYXIA.]

THE AIM: Estimate of efficiency of newborns with severe birth asphyxia treatment using systemic therapeutic hypothermia. MATERIALS AND METHODS: a retrospective open-controlled clinical research with a resolution of the Ethics;Committee performed in 33 neonates born in asphyxia and treated at the NICU All newborns due to the presence of indications, overall controlled hypothermia was conducted according to the approved protocol, using the apparatus Allon 2001". RESULTS: The neurological status at admission: Sarnat II was detected in 60.6% (20) children; Sarnat III was detected in 39.4% (13) children. The correlation ofApgar scores with the most severe hypoxic ischemic encephalopathy. Pupillary reflexes admission absent in 48.5% (16) newborns. Convulsions within first hours of lfe were observed in 57.6% (19) newborns. Convulsions within I day of life were observed in 81.8 % (27) newborns. The correlation of the amniotic infection (AI) and meconium aspiration syndrome (MAS) treatment using high-frequency mechanical ventilation (p<0,05) and prolongation of mechanical ventilation for more than 5 days (p<0,01). At the beginning of systemic hypothermia fraction of inspired oxygen (FiO2), mean airway pressure (MAP), respiratory rate (RR) were down to the 12th hour of life and reaches a minimum at the end of the third day. These trends have been observed in children with MAS. The correlation of the use of high-frequency mechanical ventilation using high doses ofcardiotonics and the transition to the infusion of epinephrine or norepinephrine (p <0.01).There were no deaths in the studying group. CONCLUSIONS: 1. Reliable predictor of the clinical outcomes severity of hypoxic-ischemic encephalopathy (HIE) by the end of the first month lf is the presence of convulsions within the first hour of lf (p<0. 03). 2. When comparing the evaluation on Apgar scale with the data of acid-base balance and severity of HIE a significant correlation between the estimation at the first minute is I point and at the fifth minute 3 point and more severe pH shift, base deficiency, hyperlactatacidosis and severe HIE. 3. MAS and AI are the most frequent accompanying diseases that complicates the severity of newborn status causing prolonged artificial ventilation and the infusion ofcardiotonics. 4. There is a decrease in all parameters of artficial lung ventilation to the twelfth hour life in early systemic hypothermia and reached minimum by the end of the third day.

Quality control of bioprosthetic heart valves by means of holographic interferometry.

BACKGROUND AND AIMS OF THE STUDY: Limited durability of porcine bioprostheses is mainly caused by the progressive development of calcification. We tested the hypothesis that hidden tissue anomalies or unfavorable stress concentrations of commercially available bioprostheses may lead to later calcification and dysfunction. Application of holographic interferometry for non-destructive testing of biological heart valves enables a full-field analysis of heart valves and reveals deformation irregularities of valve tissue. MATERIAL AND METHODS: We developed an accelerated calcification protocol for bioprosthetic heart valves including an accelerated pulsatile valve tester for simultaneous testing of 10 heart valves under identical conditions and a rapid synthetic calcification fluid containing a final Ca x P of 130 (mg/dl)2 in barbital buffer solution. Ten porcine bioprostheses (St. Jude Medical, Bioimplant) were assessed by holographic interferometry and subjected to the pulsatile accelerated calcification process. Distribution and amount of calcification was evaluated by microradiography after 12 x 10(6) and 19 x 10(6) cycles, respectively. Areas of irregular fringe patterns detected by holography as well as areas of calcification were calculated and compared using a personal computer. RESULTS: All tested bioprostheses had localized or extended areas with holographic irregularities and the accelerated valve testing protocol resulted in even macroscopically visible calcifications at various sites. Comparative analysis of the obtained microradiographs revealed that 74.2% +/- 6.0% of calcified leaflet areas lay within the previously detected holographic anomalies. CONCLUSIONS: Our first results show a strong correlation between holographic anomalies and calcification of porcine bioprostheses. We conclude that suitable methods for evaluation and quality control of bioprosthetic heart valves are available and seem to be predictive with regard to valve calcification.

Determination of scattering structures from spatial coherence measurements.

A new method of structure determination and microscopic imaging with short-wavelength radiations (charged particles, X-rays, neutrons), based on measurements of the modulus and the phase of the degree of spatial coherence of the scattered radiation, is developed. The underlying principle of the method--transfer of structural information about the scattering potential via spatial coherence of the secondary (scattering) source of radiation formed by this potential--is expressed by the generalization of the van Cittert-Zernike theorem to wave and particle scattering [A.M. Zarubin, Opt. Commun. 100 (1993) 491; Opt. Commun. 102 (1993) 543]. Shearing interferometric techniques are proposed for implementing the above measurements; the limits of spatial resolution attainable by reconstruction of the absolute square of a 3D scattering potential and its 2D projections from the measurements are analyzed. It is shown theoretically that 3D imaging with atomic resolution can be realized in a "synthetic aperture" electron or ion microscope and that a 3D resolution of about 6 nm can be obtained with a "synthetic aperture" X-ray microscope. A proof-of-principle optical experiment is presented.

Comparative analysis of glutaraldehyde-preserved porcine xenografts and fresh or glutaraldehyde-treated human aortic valves by holographic interferometry.

Although calcification and degeneration are recognized as the main causes of bioprosthetic heart valve failure, the reasons for such failure are not well understood. Hidden tissue anomalies in the valves may be the origin of later calcification. Application of hologram interferometry for non-destructive testing enables the detection of such tissue anomalies. A comparative study by holographic interferometry of ten porcine bioprosthetic valves (seven Carpentier-Edwards SAV, two BioImplant and one Valcor) with five human aortic valves before and after glutaraldehyde treatment is presented. Whereas irregularities were detected in the interferograms of eight out of ten bioprostheses, no similar distorted fringe pattern was found in the holographic interferograms of human specimens. The present results suggest that tissue abnormalities exist in standard bioprosthetic valves which are absent in human ones. These irregularities may be the origin of later calcification and valvular dysfunction.