QSOX2 Upregulated in triple-negative breast cancer exacerbates patient prognosis by stabilizing integrin β1

Breast cancer (BC) remains a significant global health threat, with triple-negative breast cancer (TNBC) standing out as a particularly aggressive subtype lacking targeted therapies. Addressing this gap, we propose Quiescin Q6 sulfhydryl oxidase 2 (QSOX2) as a potential therapeutic target, a disulfide bond-forming enzyme implicated in cancer progression. Using publicly available datasets, we conducted a comprehensive analysis of QSOX2 expression in BC tumor and non-tumor tissues, assessing its specificity across different molecular subtypes. We further explored correlations between QSOX2 expression and patient outcomes, utilizing datasets like TCGA and METABRIC. In addition, we performed in vitro experiments to evaluate QSOX2 expression in BC cell lines and investigate the effects of QSOX2 knockdown on various TNBC cellular processes, including cell proliferation, apoptosis resistance, migration, and the epithelial-to-mesenchymal transition (EMT). Our results reveal significantly elevated QSOX2 expression in BC tumor tissues, particularly in TNBC, and establish an association between high QSOX2 expression and increased patient mortality, cancer progression, and recurrence across various BC subtypes. Notably, QSOX2 knockdown in TNBC cell lines reduces cell proliferation, enhances apoptosis, and suppresses migration, potentially mediated through its influence on the EMT process. Furthermore, we identify a significant link between QSOX2 and integrin β1 (ITGB1), suggesting that QSOX2 enhances ITGB1 stability, subsequently exacerbating the malignancy of TNBC. In conclusion, elevated QSOX2 expression emerges as a key factor associated with adverse patient outcomes in BC, particularly in TNBC, contributing to disease progression through various mechanisms, including the modulation of ITGB1 stability. Our findings underscore the potential of targeting QSOX2 as a therapeutic strategy for improving patient prognoses not only in TNBC but also in other BC subtypes.

[A Study of the Fertility of a Drosophila melanogaster MS Strain with Impaired Transposition Control of the gypsy Mobile Element]

The flamenco locus is one of the main components of the piRNA pathway of regulation of mobile genetic elements (MGEs) in Drosophila melanogaster. Mutations at this locus lead to an increase in the transposition activity of MGEs and, as a result, to genetic instability. In this paper, the fertility of a genetically unstable MS strain obtained more than 25 years ago and characterized by a mutation in the flamenco locus and the presence of a functionally active copy of gypsy retrotransposon was investigated. Complex violations of the ovarian morphology were revealed in the MS strain in females: defects in the follicular layer and ring channels, as well as degradation of trophocytes, which in turn led to a decrease in reproductive abilities. Analysis of the MS strain transcriptome showed a decrease in the expression level of 40 genes encoding chorionic proteins and expression specificity at different stages of follicle development. In the F1 and F2 hybrid females from the crosses of MS females with wild type males, restoration of reproductive abilities was observed, despite the fact that half of the F2 females had the flamenco genotype and genetic instability caused by transposition of gypsy (according to the ovo^(D) test). Moreover, the frequency of gypsy transposition in the hybrid F2 females with the flamenco genotype doubled in comparison with the MS strain females. Thus, the MS strain had acquired partial suppression of the flamenco phenotype and accumulated several recessive mutations in the genes that control oogenesis after cultivation for over 25 years.

[On the problem of female infertility: A search for genetic markers]

In every one case out often, the reason behind female infertility turns out to be an orphan disease called 'hypogonadotropic hypogonadism', the single symptom of which is the reduced level of gonadotropins and, as a consequence, amenorrhea in females. Most often, hypogonadotropic hypogonadism is caused by disorder in secretion of gonadoliberin, the product of gene GNRH1. However, the disease is heterogeneous one, so it may origin from either genetic or non-genetic causes. To study the genetic component of the disease pathogenesis, we conducted molecular-genetic analysis of 11 gene-candidates controlling synthesis and secretion of gonadoliberin as well as several gene-candidates functioning as neurodevelopmental and neuroendocrine regulators. In the study participated a group of patients afflicted by hypogonadotropic hypogonadism of an isolated form (n = 10), and a control group of healthy women (n = 20). All women were of reproductive age, with no detected mutations in gene-candidates that could cause any pathological effect. The data on gene-candidates expression in white blood cells are indicative of an increased expression of gene GNRH1 in the sampled patients as compared to the control group (p < 0.05). Other genes demonstrate heterogeneous expression both in the patients group and the control group. Thus, increased expression of gene GNRH1 in blood cells appears to be associated with the isolated form of hypogonadotropic hypogonadism and, in prospect, may be used as one of the disease markers.

[Outcomes after one-stage repair of coarctation of the aorta and combined intracardiac lesions in infants]

BACKGROUND

The aim of the study was to compare the outcomes of hypothermic circulatory arrest (GCA) and selective cerebral perfusion (SCP).

PATIENTS AND METHODS

Nine patients were treated at the Bakoulev Center for Cardiovascular Surgery. All congenital heart diseases were repaired simultaneously. Group 1 (n = 4) included infants who were treated using an HCA, and the patients who underwent repair with the use of SCP were in group 2 (n = 5).

RESULTS

One patient (25%) in group 1 died in the period of thirty days after the repair. Moderate heart failure and respiratory failure occurred postoperatively with no significant difference between two groups. Recoarctation was a frequent (75%) complication after the "end to end" anastomosis creating. One patient (25%) was reoperated on day 3 after the primary repair. Two other patients (50%) were treated by balloon angioplasty. There was relatively high (75%) incidence of a prolonged open sternotomy in group 1.

CONCLUSION

There were similar results in HCA and SCP groups. A tendency for frequent prolonged open sternotomy application after HCA surgery as well as occurrence of the recoarctation after "end to end" anastomosis creating was found.

Expression of hp1 family genes and their plausible role in formation of flamenco phenotype in D. melanogaster

Results of expression analysis of transcription of the flamenco locus that controls transposition of the mobile genetic element gypsy, RNA interference system genes ago3, zuc, aub, and HP1 heterochromatin protein family genes hp1a, hp1b, hp1c, hp1d (rhino), and hp1e in D. melanogaster SS strain mutant on the flamenco gene are presented. We show that the number of transcripts in the SS strain that are formed in the flamenco locus is unchanged in some freely chosen points, and this is different from the wild-type strain where a decreased number of transcripts is observed, which clearly is a result of processing of the flamenco locus primary transcript, a predecessor of piRNA. At the same time, expression of genes of the RNA interference system is not affected, but there is a reduced level of hp1d gene expression in ovary tissue. We suggest that the hp1d gene product is directly or indirectly involved in the flamenco locus primary transcript processing.

Domesticated retroviral GAG gene in Drosophila: new functions for an old gene

The domestication of foreign genes is a powerful mechanism for new gene formation and genome evolution. It is known that domesticated retroviral gag genes in mammals not only take part in protecting against viral infection but also control cell division, apoptosis, function of the placenta, and other biological processes. In this study, we focused on the domesticated retroviral gag gene homolog (Grp) in the Drosophila melanogaster genome. According to the results of a bioinformatic analysis, the Grp gene product is primarily under purifying selection in Drosophilidae family. The Grp protein has been shown to be transmembrane. The Grp gene is expressed at the adult stage of D. melanogaster in gender-specific and tissue-specific manner. Also the Grp gene expression is increased in response to the gypsy retrovirus. A function of the protein as a component of the endosomic membrane is considered.

[Study of the transcriptional and transpositional activities of the Tirant retrotransposon in Drosophila melanogaster strains mutant for the flamenco locus]

Transpositions of the gypsy retrotransposon in the Drosophila melanogaster genome are controlled by the flamenco locus, which is represented as an accumulation of defective copies of transposable elements. In the present work, genetic control by the flamenco locus of the transcriptional and transpositional activities of the Tirant retrotransposon from the gypsy group was studied. Tissue-specific expression of Tirant was detected in the tissues of ovaries in a strain mutant for the flamenco locus. Tirant was found to be transpositionally active in isogenic D. melanogaster strains mutant for the flamenco locus. The sites of two new insertions have been localized by the method of subtractive hybridization. It has been concluded from the results obtained that the flamenco locus is involved in the genetic control of Tirant transpositions.

[Clinical and morphological parallels in mitral valve disorders in infants with atrioventricular defect]

Mitral valves tissue samplings from children with complete (13 patients) and partial (6 patients) atrioventricular defects at the age of from I month to 3 years old were examined. The biopsy material was received during the repeat surgical operation on mitral valve, performed due to residual mitral valve regurgitation grade 3-4 at the period of time from 2 days to 1 year after radical defect correction. On histological examination the areas of myxomatous tissue degeneration occupying more than 50% of mitral valves surface were found in 6 (32%) of the 19 patients. There were dispersed star-shaped cells, architectonics disturbances, deposition of acid mucopolysaccharides and increased content of matrix metalloproteinase 13 in such areas of myxomatous degeneration. The sizes of these areas correlated with mitral valve regurgitation grade. After the radical correction of atrioventricular defect the sutures on the folds and fibrous ring of the mitral valve "cut through" reliably more often in patients with wider areas of myxomatous degeneration, which indicates poor prognosis. According to the ultrastructural classification the majority of mitral valve cells regarded as fibroblasts; there also were found cells with the signs of myogenic differentiation--myofibroblasts and isolated hystiocytes. According to the immunohistochemistry assay the cells phenotype regarded as fibroblastic and endothelial differentiation; in some patients there were found cells of smooth muscle origin.

[Translational analysis of the Grp gene, a genomic homologue of the Gag gene of the gypsy retrotransposon of Drosophila melanogaster]

The only open reading frame (ORF) (CG4680) encoding the Gag related protein (Grp) gene, a homologue of gag retrotransposons with long terminal repeats (LTR retrotransposons) of the gypsy group, has been found in the Drosophila melanogaster genome. Earlier, it was shown that the gene was expressed at the transcriptional level only in adult D. melanogaster. The Grp gene has been demonstrated to be a functional gene in the D. melanogaster genome, bit its function is yet to be determined.

[Transcriptional analysis of the Grp gene, a genomic homolog of the retrotransposon gypsy gag gene, in Drosophila melanogaster]

In the present work, we studied the Grp gene (CG4680, Gag related protein) expression at the transcriptional level. It was found that at the embryonic and larval stages of D. melanogaster development the Grp expression proceeds at a low level, but it significantly increases at the adult stage. Adult individuals display a tissue-specific expression: an eleveated level of transcription is observed in the gut tissues, but not in the chitin carcass, head, and gonads. Since the gut may potentially be a primary barrier for the penetration of a viral infection, we conducted a comparative analysis of Grp gene transcription in D. melanogaster strains differing in the presence of active copies of the gypsy errantivirus and in the status of the flamenco gene controlling sensitivity to errantiviral infections. No noticeable differences in the level of Grp gene transcription were revealed. Thus, the Grp gene is not a pseudogene, but it is a functional gene of the D. melanogaster genome whose role remains to be elucidated.

[Analysis of the structure and expression of the cluster of Drosophila melanogaster genes DIP1, CG32500, CG32819, and CG14476 in the flamenco gene region]

The flamenco gene controlling transpositions of the gypsy retrovirus is localized in the 20A1-3 region, in which eight open reading frames organized in a cluster were discovered: DIP1, three repeats of CG32500 and CG32819, and CG14476. Analysis of the genes composing the cluster indicates that their transcription in Drosophila melanogaster is a stage-specific process. Comparison of the expression of these genes in the strains OreR, SS, and MS having the flamenco phenotype and in the strain 413 having the flamenco+ phenotype revealed differences only for the DIP1 gene, transcription of this gene being altered only in the OreR strain. Thus, mutant flamenco alleles are differently expressed in different strains. The structural organization of the flamenco gene region was studied in different Drosophila species: D. sechellia, D. simulans, D. mauritiana, D. yakuba, D. erecta, D. virilis, D. ananassae, D. grimshawi, and D. pseudoobscura. The genes of the cluster were found to be highly conserved in genomes of different species, but in none of them, except D. sechellia, the structural organization of the region repeats the structure of the D. melanogaster cluster.

[Molecular phylogeny and systematics of Drosophila retrotransposons and retroviruses]

Full classification of Drosophila melanogaster retrotransposons with long terminal repeats (LTR-retrotransposons) has been recomposed, and their evolutional analysis in sequenced genomes of different species of drosophila and other arthropods has been carried out. D. melanogaster LTR-retrotransposons are divided in three groups: gypsy (one, two or three open reading frames - ORFs), copia (one ORF), BEL (one ORF). Gypsy group is divided into three subgroups. Subgroup I is underrepresented by retrotransposons-retroviruses with three ORFs and their derivatives which have lost the env gene (ORF3). Subgroup II is underrepresented by retrotransposons with two ORFs, subgroup III - by retrotransposons with one ORF. Comparative analysis of homologs of gypsy group LTR-retrotransposons evidences that subgroups I and II are only in genomes of Lepidoptera and Diptera. Gypsy group of LTR-retrotransposons with one and two ORFs are found in almost all genomes of arthropods. Most of the families of D. melanogaster gypsy group LTR-retrotransposons have close homologs in genomes of other species of drosophila. A degree of identity of retrotransposons sequences is correlated with a degree of relation between species of drosophila; it's evidences about vertical transmission of retrotransposons. Obvious cases of horizontal transfer of some mobile elements have been detected including retrotransposons without the env gene. Homologs of distinct ORFs of retrotransposons - genes gag and env - have been found. Gene-homolog of the gag gene - Grp (CG4680) - is under purifying selection; so it has an important function in drosophila genome.

[Analysis of the structure and expression of the DIP1 gene in Drosophila melanogaster strains mutant for the flamenco gene]

DIP1 gene transcription was analyzed with the use of RT-PCR in three Drosophila melanogaster strains with the flamenco- phenotype (flam(SS), flam(MS), and flam(Ore)) and in one flamenco+ strain at the stages of embryos (0-24 h), third-instar larvae, and adult flies. The mutant strains flam(SS) and flam(Ore) lack an active copy of transposon gypsy. Theflam(MS) strain was obtained by introducing an active copy of gypsy in flies of theflam(SS) strain and is characterized by a high rate of gypsy transpositions. The experiments showed that at least five forms of DIP1 gene transcripts are produced. The form of cDNA corresponding to CDS DIP1-d was discovered only in embryos. It was found that DIP1 gene transcription depends on the age of flies: at the larval stage the level of transcription is significantly reduced. However, no reduction of gene transcription is observed in theflam(Ore) strain. These results suggest that the flamenco- phenotype may be associated with an alteration of DIP1 gene transcription, as in differentflamenco- strains the DIP1 gene expression is changed differently.

[Results of bidirectional cavapulmonary shunt operation without cardiopulmonary bypass in children with complicated congenital heart defects during the first year of life]

The authors present results of bidirectional cavapulmonary shunt operation without cardiopulmonary bypass for the treatment of complicated congenital heart defects. Temporary blood shunting during surgical intervention enables cavapulmonary anastomosis to be created without making resort to artificial circulation (AC) and limitation on the time of superior vena cava occlusion. The proposed method is free from additional risks and excludes negative effects of AC. It allows for conversion to AC as appropriate at any time during surgery in the "bypass stand-by" regime.

[Molecular evolution of mobile elements of the gypsy group: a homolog of the gag gene in Drosophila]

Retrotransposons of the gypsy group of Drosophila melanogaster that are structurally similar to retroviruses of vertebrates occupy an important place among retroelements of eukaryotes. The infectious abilities of some retrotransposons of this group (gypsy, ZAM, and Idefix) have been demonstrated experimentally, and therefore they are true retroviruses. It is supposed that retrotransposons can evolve acquiring new components, the sources of which remain to be elucidated. In this work, the CG4680 gene (Gag related protein, Grp) homologous to gag of retrotransposons of the gypsy group has been identified in the genome of D. melanogaster and characterized. The Grp gene product has a highly conserved structure in different species of the Drosophilidae family and is under of stabilizing selection, which suggests its important genomic function in Drosophila. In view of the earlier data, it can be concluded that homologous genes of all components of gypsy retrotransposons are present in the Drosophila genome. These genes can be both precursors and products of domestication of retrovirus genes.

[Surgical treatment of Taussig-Bing anomaly in children in the first year of life]

The history of surgical treatment, clinical features, and main variants of correction of Taussig-Bing anomaly in children during the first year of life is briefly reviewed including original data obtained in the Department of Urgent Surgery of newborn and first-year infants, A. N. Bakulev Research Centre of Cardiovascular Surgery for the period of 2000-2006.

[Evolution from retrotransposons to retroviruses: origin of the env gene]

In genome of Drosophila melanogaster, various families of retrotransposons with different combination of functional domens and mechanisms of transposition are present. However only retrotransposons of gypsy family are retroviruses related to errantiviruses. Other families seemingly appeared as intermediate forms of retroviruses evolution. Despite the fact that the question on origin of retroviruses remains unclear, now the hypothesis of their origin from retrotransoposons can be considered the most consistent. Infectious properties of errantiviruses are linked to the presence of the third open reading frame (the env gene). Acquisition of the env gene conversed retrotransposons into retroviruses. So, origin of this gene is of special interest. Homologues of the env gene of errantiviruses are discovered in genomes of D. melanogaster, as well as in baculoviruses and in bacteria Wolbachia pipientis, the endosymbiont of Drosophila. It was shown that homologue of the env gene come to Wolbachia genome from Drosophila genome by horizontal transfer of the gypsy group retrotransposon. Thus, Wolbachia was not a donor of the env gene for errantiviruses. Seemingly, errantiviruses captured the baculoviral homologue of the env gene (f). However origin of the f gene is not clear. At the same time the env gene homologue in D. melanogaster genome exist (Iris). It must not be ruled out that the Iris gene was the source of the env gene of errantiviruses and baculoviruses.

[Evolution of errantiviruses of Drosophila melanogaster. Strategy 2: from retroviruses to retrotransposons]

Drosophila melanogaster retrotransposons of the gypsy group are considered to be potential errantiviruses. Their infectivity is caused by the functional activity of the third open reading frame (ORF3) encoding the Env protein, which was probably captured from baculoviruses. Mobile genetic elements (MGEs) of the gypsy group can be conventionally divided into three subgroups: with three ORFs, with a defective ORF3, and without the ORF3. To establish the patterns of evolution of gypsy retrotransposons in D. melanogaster, the members of the three subgroups were examined. Structural analysis of retrotransposons opus and rover, which carry a defective ORF3, as well as retrotransposons Burdock, McClintock, qbert, and HMS-Beagle, which lack the ORF3, suggests that the evolution of these MGEs followed the pattern of loosing the ORF3. At the same time, an MGE of the same subgroup, Transpac, may be an ancestral form, which had acquired the env gene and gave rise to the first errantiviruses. The capture of the ORF3 by retrotransposons provided their conversion to a fundamentally new state. However, the ORF3 in the genome is not subjected to strong selective pressure, because it is not essential for intragenomic transpositions. Because of this, the process of its gradual loss seems quite natural.

The treatment of chronic hepatitis C in HIV-infected patients: a meta-analysis

OBJECTIVE

Hepatitis C virus (HCV) disease progression appears to be accelerated in patients coinfected with HIV. The impact of HCV on coinfected patients is being realized as patients are now living longer. The objective of our study was to further elucidate incremental improvement and safety concerns with combinations of pegylated interferon (peginterferon), interferon and ribavirin based on data obtained from prospective randomized controlled trials.

METHODS

A search of MEDLINE and the Cochrane database for material published between 1966 and 29 August 2005 and a hand search of abstracts from national meetings held between 2001 and August 2005 were performed. Trials comparing the use of peginterferon plus ribavirin vs peginterferon or interferon plus ribavirin were assessed.

RESULTS

In six randomized controlled trials, 1756 patients were randomized. Sustained virological response was greater for patients treated with peginterferon plus ribavirin compared with patients treated with interferon plus ribavirin [odds ratio (OR) 3.00; 95% confidence interval (CI) 2.27-3.96]. This increased sustained virological response with peginterferon and ribavirin was found for patients with HCV genotype 1 or 4 (OR 4.40; 95% CI 2.75-7.03) and genotype 2 or 3 (OR 2.56; 95% CI 1.71-3.85). Sustained virological responses were also higher with peginterferon and ribavirin as compared with peginterferon monotherapy (OR 2.60; 95% CI 1.84-3.67). Severe adverse effects (OR 1.09; 95% CI 0.74-1.4) and withdrawal rates (OR 0.97; 95% CI 0.75-1.25) were similar between patients treated with peginterferon plus ribavirin and patients treated with interferon plus ribavirin.

CONCLUSIONS

Patients with chronic HCV/HIV coinfection have a greater likelihood of achieving a sustained virological response with peginterferon plus ribavirin. The likelihoods of serious adverse effects and study withdrawal were similar.

[HB mobile element in the Drosophila melanogaster genome: structural and functional analyses]

The structure was analyzed for 60 annotated copies of the mobile genetic element (MGE) HB from the Drosophila melanogaster genome. The genomic distribution of HB copies was studied, and preferential insertion sites (hot spots) were identified, which presumably amount to several kilobases. Structural analysis of the open reading frame (ORF) and terminal repeats of HB was performed. All 26 HB copies retaining the ORF sequence have a stop codon in the same position. Consequently, the HB ORF proved indeed to code for an enzyme of 148 amino acid residues, relatively small for Tc1-family transposases. The ORF consensus sequence was established. HB{}1185 was identified as the only HB copy potentially coding for a functional protein. All 37 repeat-containing HB copies were analyzed. Of these, only four had functional terminal sequences, lacking, however, a functional transposase gene. A new 7762-bp copy of MGE roo was found in the D. melanogaster genome; the copy was earlier unavailable from databases and represents an insert in the HB{}1605 sequence.

[Characteristics of the structural organization of the DIP1 gene in Drosophila melanogaster strains mutant for the flamenco gene]

Molecular cloning of the DIP1 gene located in the 20A4-5 region has been performed from the following strains with the flamenco phenotype: flamSS (SS) and flamMS (MS) characterized by a high transposition rate of retrotransposon gypsy (mdg4), flampy + (P) carrying the insertion of a construction based on the P element into the region of the flamenco gene, and flamenco+. The results of restriction analysis and sequencing cloned DNA fragments has shown that strains flamSS, flamMS, flampy +(P), and flamenco+ considerably differ from one another in the structure of DIP1. Strains flamss and flamMS have no Dral restriction site at position 1765 in the coding region of the gene, specifically, in the domain determining the signal of the nuclear localization of the DIP1 protein. This mutation has been found to consist in a nucleotide substitution in the recognition site of DraI restriction endonuclease, which is transformed from TTTAAA into TTTAAG and, hence, is not recognized by the enzyme. This substitution changes codon AAA into AAG and is translationally insignificant, because both triplets encode the same amino acid, lysine. The Dral gene of strainsflamSS andflamMS has been found to contain a 182-bp insertion denoted IdSS (insertion in DIP1 strain SS); it is located in the second intron of the gene. The IdSS sequence is part of the open reading frame encoding the putative transposase of the mobile genetic element HB1 belonging to the Tcl/mariner family. This insertion is presumed to disturb the conformations of DNA and the chromosome, in particular, by forming loops, which alters the expression of DIPI and, probably, neighboring genes. In strains flamenco+ and flampy + (P), the IdSS insertion within the HB1 sequence is deleted. The deletion encompasses five C-terminal amino acid residues of the conserved domain and the entire C-terminal region of the putative HB1 transposase. The obtained data suggest that DIP1 is involved in the control of gypsy transpositions either directly or through interaction with other elements of the genome.

[Precise excision of long terminal repeats of the gypsy (mdg4) retrotransposon of Drosophila melanogaster detected in Escherichia coli cells is explained by its integrase function]

An Escherichia coli model system was developed to estimate the capacity of the integrase of the Drosophila melanogaster retrotransposon gypsy (mdg4) for precise excision of the long terminal repeat (LTR) and, hence, the entire gypsy. The gypsy retrotransposon was cloned in the form of a PCR fragment in the pBlueScript II KS+ (pBSLTR) vector, and the region of the second open reading frame (INT ORF2) of this element encoding integrase was cloned under the lacZ promoter in the pUC19 vector and then recloned in pACYC184 compatible with pBSLTR. The LTR was cloned in such a manner that its precise excision from the recombinant plasmid led to the restoration of the nucleotide sequence and the function of the ORF of the lacZ gene contained in the vector; therefore, it was detected by the appearance of blue colonies on a medium containing X-gal upon IPTG induction. Upon IPTG induction of E. coli XL-1 Blue cells obtained by cotransformation with plasmids pACCint and pBSLTR on an X-gal-containing medium, blue clones appeared with a frequency of 1 x 10(-3) to 1 x 10(-4), the frequency of spontaneously appearing blue colonies not exceeding 10(-9) to 10(-8). The presence of blue colonies indicated that that the integrase encoded by the INT ORF2 (pACYC 184) fragment was active. After the expression of the integrase, it recognized and excised the gypsy LTR from pBSLTR, precisely restoring the nucleotide sequence and the function of the lacZ gene, which led to the expression of the beta-galactosidase enzymatic activity. PCR analysis confirmed that the LTR was excised precisely. Thus, the resultant biplasmid model system allowed precise excisions of the gypsy LTR from the target site to be detected. Apparently, the gypsy integrase affected not only the LTR of this mobile element, but also the host genome nucleotide sequences. The system is likely to have detected only some of the events occurring in E. coli cells. Thus, the integrase of gypsy is actually capable of not only transposing this element by inserting DNA copies of the gypsy retrotransposon to chromosomes of Drosophila, but also excising them, gypsy is excised via a precise mechanism, with the original nucleotide sequence of the target site being completely restored. The obtained data demonstrate the existence of alternative ways of the transposition of retrotransposons and, possibly, retroviruses, including gypsy (mdg4).

[Diagnostic algorithms and features of clinical course of congenital heart diseases in infants with lung anomalies]

The paper discusses the influence of lung anomalies on the progress of congenital heart diseases (CHD) in infants, as well as diagnostic value of radiography and ultraspeed computed tomography (CT). The four-year experience of the authors includes preoperative examination of 178 infants with CHD (mean age 5.8 +/- 0.6 months, mean weight 5.2 +/- 0.3 kg). Lung anomalies were determined in 24 patients (13.5%) on plain films and in 85 patients (47.8%)--by means of CT. The stenosis of main bronchi in combination with lobar emphysema and lung hypoplasia were found to be the most frequent and severe predictors of respiratory disorders. The obtained data suggest that CT examination may be recommended in infants with CHD for precise diagnostics of associated lung anomalies and further prevention or early management of respiratory complications.

[Retrotransposon gtwin: structural analysis and distribution in Drosophila melanogaster strains]

A search for noncanonical variants of the gypsy retrotransposon (MDG4) in the genome of the Drosophila melanogaster strain G32 led to the cloning of four copies of the poorly studied 7411-bp gtwin element. Sequence analysis showed that gtwin belongs to a family of endogeneous retroviruses, which are widespread in the Drosophila genome and have recently been termed insect erantiviruses. The gtwin retrotransposon is evolutionarily closest to MDG4, as evident from a good alignment of their nucleotide sequences including ORF1 (the pol gene) and ORF3 (the env gene), as well as the amino acid sequences of their protein products. These regions showed more than 75% homology. The distribution of gtwin was studied in several strains of the genus Drosophila. While strain G32 contained more than 20 copies of the element, ten other D. melanogaster strains carried gtwin in two to six copies per genome. The gtwin element was not detected in D. hydei or D. virilis. Comparison of the cloned gtwin sequences with the gtwin sequence available from the D. melanogaster genome database showed that the two variants of the mobile element differ by the presence or absence of a stop codon in the central region of ORF3. Its absence from the gtwin copies cloned from the strain G32 may indicate an association between the functional state of ORF3 and amplification of the element.

[Study of male mating behavior in some Drosophila melanogaster strains in experiments with fertilized females]

Male courtship ritual is among the main behavioral characteristics of Drosophila. This is a complex, genetically determined process consisting of four general stages: orientation, vibration, licking, and attempts at copulation (or successful copulation). Several genes are known that control some stages of this behavior. Most of them have pleiotropic effects and are involved in other biological processes. Earlier, we have shown that a mutation in locus flamenco (20A1-3), which controls transposition and infectivity of retrotransposon gypsy (MDG4), is involved in the genetic control of behavior. In strains mutant for this locus, the male mating activity is decreased and the structure of courtship ritual is changed. To understand the mechanisms of these changes, it is important to study all behavioral stages in genetically identical strains. For this purpose, the normal allele of gene flamenco from the X chromosome of the wild-type strain (stock) Canton S was introduced into strain SS carrying flamMS. This offers new opportunities in studying the role of gene flamenco in the control of mating behavior in Drosophila.

[Male reproductive behavior in Drosophila melanogaster strains with different alleles of the flamenco gene]

The allelic state of gene flamenco has been determined in a number of Drosophila melanogaster strains using the ovoD test. The presence of an active copy of gypsy in these strains was detected by restriction analysis. Then male reproduction behavior was studied in the strains carrying a mutation in gene flamenco. In these experiments mating success has been experimentally estimated in groups of flies. It has been demonstrated that the presence of mutant allele flamMS decreases male mating activity irrespective of the presence or absence of mutation white. The active copy of gypsy does not affect mating activity in the absence of the mutation in gene flamenco. Individual analysis has demonstrated that that mutation flamMS results in characteristic changes in courtship: flamMS males exhibit a delay in the transition from the orientation stage to the vibration stage (the so-called vibration delay). The role of locus flamenco in the formation of male mating behavior in Drosophila is discussed.

Experimental validation of videoendoscopic isolation and occlusion of the bloodflow in open ductus arteriosus

The potentialities of videoendoscopic isolation and extravasal occlusion of large vessels with titanium clips were studied in acute and chronic experiments on 36 animals and anatomic studies on 5 human cadavers. The number and optimal sites for insertion of trocars and disposition of instruments and thoracoscope for isolation of open ductus arteriosus were determined. A method for videoendoscopic isolation of vessels is developed and possible complications and measures for their liquidation evaluated. High efficiency and low traumatism of videoendoscopic operation are proven under condition of strict adherence to methodology and sufficient qualification of the surgeon in endosurgical manipulations.

[Retrotransposon MDG4 and its role in genetic instability of a mutator strain of Drosophila melanogaster]

This article summarizes the results of a ten-year study of genetic instability of a mutator strain of Drosophila melanogaster caused by transposition of the gypsy retrotransposon. The results of other authors working with an analogous system are analyzed. Possible mechanisms are suggested for the interaction of gypsy with the cell gene flamenco that participates in transposition control of this mobile element.

Extravasal occlusion of large vessels with titanic clips: efficiency, indications, and contraindications

The mechanism of extravasal occlusion of blood vessels with titanic clips "Atrauclip" and "Ligaclip extra" was studied in order to reveal indications and contraindications to their use. Occlusion with the clips of both types was ineffective in vessels with a diameter of >7.0 mm. Arteritis or the presence of an intravascular occlusion facility in the vessel were also the contraindications for clip occlusion. In overcases the procedure of occlusion with titanic clips was efficient and atraumatic.

[Mobile genetic element MDG4 (gypsy) in Drosophila melanogaster. Features of structure and regulation of transposition]

Distribution of two structural functional variants of the MDG4 (gypsy) mobile genetic element was examined in 44 strains of Drosophila melanogaster. The results obtained suggest that less transpositionally active MDG4 variant is more ancient component of the Drosophila genome. Using Southern blotting, five strains characterized by increased copy number of MDG4 with significant prevalence of the active variant over the less active one were selected for further analysis. Genetic analysis of these strains led to the suggestion that some of them carry factors that mobilize MDG4 independently from the cellular flamenco gene known to be responsible for transposition of this element. Other strains probably contained a suppressor of the flam- mutant allele causing active transpositions of the MDG4. Thus, the material for studying poorly examined relationships between the retrovirus and the host cell genome was obtained.

[Some behavioral features in Drosophila melanogaster lines carrying a flamenco gene mutation]

Olfactory sensitivity and locomotor activity was assayed in Drosophila melanogaster strains carrying a mutation of the flamenco gene, which controls transposition of the mobile genetic element 4 (MGE4) retrotransposon the gypsy mobile element. A change in olfactory sensitivity was detected. The reaction to the odor of acetic acid was inverted in flies of the mutator strain (MS), which carried the flam mutation and active MGE4 copies and were characterized by genetic instability. Flies of the genetically unstable strains displayed a lower locomotor activity. The behavioral changes in MS flies can be explained by the pleiotropic effect of the flam mutation or by insertion mutations which arise in behavior genes as a result of genome destabilization by MGE4.

Two variants of the Drosophila melanogaster retrotransposon gypsy (mdg4): structural and functional differences, and distribution in fly stocks

Two variants of the Drosophila melanogaster retrotransposon gypsy were subjected to detailed structural and functional analysis. A series of hybrid constructs containing various combinations of "active" and "inactive" gypsy copies were tested for their ability to produce new DNA copies in cultured cells by means of reverse transcription. It was shown that the previously demonstrated variations in retrotranspositional activity are associated with either one or both of two amino acid substitutions at the beginning of ORF2. The first substitution is located at the boundary between the putative protease and reverse transcriptase domains and, hence, may influence the processing of the polyprotein. The other substitution may alter reverse transcriptase activity since it is located in the second of the seven conserved domains of the RT gene. To address the question of the evolutionary relationship between the two gypsy variants, their distribution was analyzed in among various fly stocks. Southern analysis revealed that all D. melanogaster strains studied so far contain the "inactive" gypsy variant, while the "active" copies are present only in some strains; most of the latter were established from flies recently isolated from natural populations. Finally, in stocks carrying the flamenco mutation the "active" gypsy variant is much more abundant than the "inactive" form. Possible scenarios for the orgin of the "active" form of gypsy are discussed.

Use of a conformational radical clock for evaluating alkyllithium-mediated cyclization reactions

The reductive lithiation of nitrile 9 led to the cyclic product 11 as a single diastereomer in 42% ee. The intermediate radical is a conformational radical clock. The radical lifetime can be determined from the optical purity of the product 11. We show that the lifetime of the intermediate radical is too brief to allow a radical cyclization, and thus the cyclization proceeds through an alkyllithium intermediate.

[Interlineage distribution and characteristics of the structure of two subfamilies of Drosophila melanogaster MDG4 (gypsy) retrotransposon]

The distribution of two variants of MDG4 (gypsy) was analyzed in several Drosophila melanogaster strains. Southern blot hybridization revealed the inactive variant of MDG4 in all strains examined and active MDG4 only in some of them. Most of the strains harboring the active MDG4 variant were recently isolated from natural populations. It is of interest that the active MDG4 prevailed over the inactive one only in strains carrying the mutant flamenco gene. Several lines were analyzed in more detail. The number of MDG4 sites on salivary-gland polytene chromosomes was established via in situ hybridization, and MDG4 was tested for transposition using the ovoD test.

[Mating success and courtship ritual in strains of Drosophila melanogaster carrying mutation flamenco]

Mating success was examined in groups of Drosophila melanogaster carrying mutation flamMS (SS, MSn1-2, and MSn1-3) and in wild-type flies. The proportion of normally copulating males was significantly lower in the mutant strains. The reduction in mating efficiency was caused by changes in male behavior rather than in female attractiveness. Individual analyses showed that male mating behavior in strains carrying flamMS was qualitatively and quantitatively different from that in the wild-type strain Canton S. The proportion of males that performed consecutive courtship stages was significantly lower in the mutant strains. The sequence and duration of some courtship stages (in particular, orientation and wing vibration) in mutant flies was shown to be altered. The significance of the flamenco locus in regulation of processes occurring at the organismal level are discussed.

[Genomic factors regulating the transposition of drosophila mobile elements]

Data on regulation and genetic control of transposition of mobile genetic elements (ME) in Drosophila are reviewed with special emphasis on the most abundant and best studied class of ME, retrotransposons. The effects of cis- and trans-acting factors on their expression are analyzed. Loci of the host genome involved in regulating their transposition are considered.

Radiation tolerance of transverse rectus abdominis myocutaneous-free flaps used in immediate breast reconstruction

The authors determine the effects of postoperative radiation therapy on flap and local control outcomes in patients who have undergone immediate transverse rectus abdominis myocutaneous (TRAM)-free flap reconstruction after modified radical mastectomy for locally advanced breast cancer. Details of surgery, chemotherapy, and radiation therapy for 21 patients who had undergone immediate TRAM-free flap reconstruction after modified radical mastectomy were gathered retrospectively. The outcomes examined were flap complications, overall cosmesis, and local recurrence rate. Radiation therapy was indicated for large primary tumors (T3-T4), close or positive margins, or extensive nodal disease. With a mean follow-up interval of 19 months, there have been no flap complications or losses. Cosmesis was rated as excellent by 60% of patients, good by 30%, and fair by the remaining 10%. Three patients thought that radiation had improved cosmesis, one noted worse cosmesis, and the remainder thought it had no effect on cosmesis. The local control rate was 86%. Postreconstruction irradiation of TRAM-free flaps used in immediate reconstruction for locally advanced breast cancer appears safe and cosmetically acceptable.

The physical state of mannitol after freeze-drying: effects of mannitol concentration, freezing rate, and a noncrystallizing cosolute

The objectives of this study were to (1) measure the effects of freezing rate and mannitol concentration on the physical state of freeze-dried mannitol when mannitol is present as a single component, (2) determine the relative concentration threshold above which crystalline mannitol can be observed by X-ray powder diffraction in the freeze-dried solid when a variety of noncrystallizing solutes are included in the formulation, and (3) measure the glass transition temperature of amorphous mannitol and to determine the degree to which the glass transition temperature of freeze-dried solids consisting of mannitol and a disaccharide is predicted by the Gordon-Taylor equation. Both freezing rate and mannitol concentration influence the crystal form of mannitol in the freeze-dried solid when mannitol is present as a single component. Slow freezing of 10% (w/v) mannitol produces a mixture of the alpha and beta polymorphs, whereas fast freezing of the same solution produces the delta form. Fast freezing of 5% (w/v) mannitol results primarily in the beta form. The threshold concentration above which crystalline mannitol is detected in the freeze-dried solid by X-ray diffraction is consistently about 30% (w/w) when a second, noncrystallizing solute is present, regardless of the nature of the second component. The glass transition temperature of amorphous mannitol measured from the quench-cooled melt is approximately 13 degreesC. Accordingly, mannitol is an effective plasticizer of freeze-dried solids when the mannitol remains amorphous. Glass transition temperatures of mixtures of mannitol and the disaccharides sucrose, maltose, trehalose, and lactose are well predicted by the Gordon-Taylor equation with values of k in the range of 3 to 4.

Kinetics of Low pH Induced Aggregation of Equine IgG

The kinetics of soluble aggregate formation in equine IgG was studied in the pH 3.4-4.3 range and ionic strength between 0.02 and 0.5 M, and a diagram describing aggregation kinetics as diffusion limited, reaction limited, or transitional as a function of pH and ionic strength was constructed. Aggregation rate is limited by the degree of electrostatic repulsion between the protein molecules in the pH 4.0-4.5 range. Below pH 4.0, a greater degree of attractive force is present, most likely from protein unfolding, and electrostatic repulsion no longer determines the rate of aggregation. The aggregation rate increases with decreasing pH, and at pH 3.4 the aggregation rate is diffusion limited. The pH range separating reaction-limited and diffusion-limited kinetics decreases with increasing ionic strength, indicating charge shielding from the buffer solution influences the aggregation rate. Copyright 1997 Academic Press.

[Analysis of spontaneous and ethylmethanesulfonate-induced visible mutations in the genetically unstable MS, w strain of Drosophila melanogaster]

We analyzed genetic effects of ethylmethanesulfonate (EMS) on mature sperm of males of the Drosophila melanogaster MS, w strain. The frequency of induced mutations was estimated in the X chromosome, in five loci of chromosome 2 (b, j, pr, cn, and vg), and in eight loci of chromosome 3 (ru, h, th, st, cu, sr, es, and ca). Mutability was significantly increased in the genetically unstable MS, w strain in comparison with the reference laboratory ss, w strain. In MS, w, genetic instability was characteristic of more than 50% EMS-induced mutations. Analysis of the mutation spectrum revealed a specific distribution along the chromosomes. In MS, w, exhibition of spontaneous and induced instability was shown to be similar. This could imply a common mechanism of control of mutability involving transpositions of mobile genetic elements.

Precise excision of the retrotransposon gypsy from the forked and cut loci in a genetically unstable D. melanogaster strain

The genetically unstable Mutator Strain of D. melanogaster is characterised by a high frequency of spontaneous mutations and their reversions. Three forked mutants were obtained independently and several reversions arose spontaneously with frequency of 10(-3)-10(-4). The sites of integration and excision of the gypsy retrotransposon were analysed by Southern blot analysis and sequencing of PCR fragments. In all cases gypsy had inserted at the end of the third exon of the major transcript of the forked gene, causing the duplication of TCCA target sequence. All the reversions resulted from precise excision of the gypsy. A double mutant containing ct6 and f1, caused by gypsy insertions into untranslated regions of the corresponding genes, was constructed. Two spontaneous ct6f+ revertants as well as one ct+f1 revertant were obtained from this line. Sequence analysis of gypsy integration and excision sites revealed that in all cases gypsy excision was also precise. These experiments constitute the first demonstration of precise excision of LTR-containing elements from their host genomes.

[Analysis of dominant and recessive sex-linked lethal mutations induced by low radiation doses in genetically different strains of Drosophila melanogaster w and MS]

Frequencies of induced recessive sex-linked lethal mutations (RSLLM) and dominant lethal mutations (DLM) were analyzed in genetically different Drosophila melanogaster strains w and ms after their exposure to radiation on radioactive soil in laboratory conditions. The RSLLM test applied to males after their 14-day radiation exposure yielded controversial results. An analysis of induced and spontaneous DLM demonstrated an increase in the frequency of early embryonic lethal mutations in the experiment (radiation exposure) in comparison with the control (spontaneous mutation rate) in both strains examined.