Human papillomavirus (HPV) is a well-known pathogen for lower genital tract neoplasias, yet little is known regarding HPV prevalence in Bulgaria. The aim of this study was to investigate the prevalence of HPV DNA and to determine HPV types distribution among women with normal and abnormal cytology. Cervical smears with different cytological diagnoses were collected from 355 Bulgarian patients. The cohort of patients selected is the biggest ever studied in this country. Using the Roche Linear Array HPV Genotyping Test, papillomavirus DNA was found in 217 out of the 355 samples, 164 of which had only one and 53 had more than one HPV type. The distribution of the viruses tested in 355 samples was as follows: (i) the most common type was HPV 16, which was found in 61 samples; (ii) the next most frequent HPV type was HPV 33, found in 14 of the samples. A high prevalence of HPV infection was observed in this study. As HPV infection has a high correlation with cervical cancer, this study emphasizes the need for both primary prevention of cervical cancer with HPV vaccines as well as secondary prevention with screening. Currently, two HPV vaccines are included in the National immunization schedule in Bulgaria. Thus, new clinical studies will benefit from patient stratification by the presence or absence of HPV, and by designing separate clinical trials specifically for HPV associated cancers.
Wild berry species are known to exhibit a wide range of pharmacological activities. They have long been traditionally applied for their antiseptic, antimicrobial, cardioprotective and antioxidant properties. The aim of the present study is to reveal the potential for selective antiviral activity of total methanol extracts, as well as that of the anthocyanins and the non-anthocyanins from the following wild berries picked in Bulgaria: strawberry (Fragaria vesca L.) and raspberry (Rubus idaeus L.) of the Rosaceae plant family, and bilberry (Vaccinium myrtillis L.) and lingonberry (Vaccinium vitis-idaea L) of the Ericaceae. The antiviral effect has been tested against viruses that are important human pathogens and for which chemotherapy and/or chemoprophylaxis is indicated, namely poliovirus type 1 (PV-1) and coxsackievirus B1 (CV-B1) from the Picornaviridae virus family, human respiratory syncytial virus A2 (HRSV-A2) from the Paramyxoviridae and influenza virus A/H3N2 of Orthomyxoviridae. Wild berry fruits are freeze-dried and ground, then total methanol extracts are prepared. Further the extracts are fractioned by solid phase extraction and the non-anthocyanin and anthocyanin fractions are eluted. The in vitro antiviral effect is examined by the virus cytopathic effect (CPE) inhibition test. The results reveal that the total extracts of all tested berry fruits inhibit the replication of CV-B1 and influenza A virus. CV-B1 is inhibited to the highest degree by both bilberry and strawberry, as well as by lingonberry total extracts, and influenza A by bilberry and strawberry extracts. Anthocyanin fractions of all wild berries strongly inhibit the replication of influenza virus A/H3N2. Given the obtained results it is concluded that wild berry species are a valuable resource of antiviral substances and the present study should serve as a basis for further detailed research on the matter.
Balkan endemic nephropathy (BEN) represents a chronic progressive interstitial nephritis in striking correlation with uroepithelial tumours of the upper urinary tract. The disease has endemic distribution in the Danube river regions in several Balkan countries.DNA methylation is a primary epigenetic modification that is involved in major processes such as cancer, genomic imprinting, gene silencing, etc. The significance of CpG island methylation status in normal development, cell differentiation and gene expression is widely recognized, although still stays poorly understood.
To better define the structure and origin of the Bulgarian paternal gene pool, we have examined the Y-chromosome variation in 808 Bulgarian males. The analysis was performed by high-resolution genotyping of biallelic markers and by analyzing the STR variation within the most informative haplogroups. We found that the Y-chromosome gene pool in modern Bulgarians is primarily represented by Western Eurasian haplogroups with ? 40% belonging to haplogroups E-V13 and I-M423, and 20% to R-M17. Haplogroups common in the Middle East (J and G) and in South Western Asia (R-L23*) occur at frequencies of 19% and 5%, respectively. Haplogroups C, N and Q, distinctive for Altaic and Central Asian Turkic-speaking populations, occur at the negligible frequency of only 1.5%. Principal Component analyses group Bulgarians with European populations, apart from Central Asian Turkic-speaking groups and South Western Asia populations. Within the country, the genetic variation is structured in Western, Central and Eastern Bulgaria indicating that the Balkan Mountains have been permeable to human movements. The lineage analysis provided the following interesting results: (i) R-L23* is present in Eastern Bulgaria since the post glacial period; (ii) haplogroup E-V13 has a Mesolithic age in Bulgaria from where it expanded after the arrival of farming; (iii) haplogroup J-M241 probably reflects the Neolithic westward expansion of farmers from the earliest sites along the Black Sea. On the whole, in light of the most recent historical studies, which indicate a substantial proto-Bulgarian input to the contemporary Bulgarian people, our data suggest that a common paternal ancestry between the proto-Bulgarians and the Altaic and Central Asian Turkic-speaking populations either did not exist or was negligible.
Disoxaril inhibits enterovirus replication by binding to the hydrophobic pocket within the VP1 coat protein, thus stabilizing the virion and blocking its uncoating. Disoxaril-resistant (RES) mutants of the Coxsackievirus B1 (CVB1/RES) were derived from the wild disoxaril-sensitive (SOF) strain (CVB1/SOF) using a selection approach. A disoxaril-dependent (DEP) mutant (CVB1/DEP) was obtained following nine consecutive passages of the disoxaril-resistant mutant in the presence of disoxaril. Phenotypic characteristics of the disoxaril mutants were investigated. A timing-of-addition study of the CVB1/DEP replication demonstrated that in the absence of disoxaril the virus particle assembly stopped. VP1 RNA sequences of disoxaril mutants were compared with the existing Gen Bank CVB1 reference structure. The amino acid sequence of a large VP1 196-258 peptide (disoxaril-binding region) of CVB1/RES was significantly different from that of the CVB1/SOF. Crucially important changes in CVB1/RES were two point mutations, M213H and F237L, both in the ligand-binding pocket. The sequence analysis of the CVB1/DEP showed some reversion to CVB1/SOF. The amino acid sequences of the three VP1 proteins are presented.
Oncolytic viruses with their capacity to specifically replicate in and kill tumor cells emerged as a novel class of cancer therapeutics. Rat oncolytic parvovirus (H-1PV) was used to treat different types of cancer in preclinical settings and was lately successfully combined with standard gemcitabine chemotherapy in treating pancreatic ductal adenocarcinoma (PDAC) in rats. Our previous work showed that the immune system and particularly the release of interferon-gamma (IFN?) seem to mediate the anticancer effect of H-1PV in that model. Therefore, we reasoned that the therapeutic properties of H-1PV can be boosted with IFN? for the treatment of late incurable stages of PDAC like peritoneal carcinomatosis. Rats bearing established orthotopic pancreatic carcinomas with peritoneal metastases were treated with a single intratumoral (i.t.) or intraperitoneal (i.p.) injection of 5 x 10? plaque forming units of H-1PV with or without concomitant IFN? application. Intratumoral injection proved to be more effective than the intraperitoneal route in controlling the growth of both the primary pancreatic tumors and peritoneal carcinomatosis, accompanied by migration of virus from primary to metastatic deposits. Concomitant i.p. treatment of H-1PV with recIFN? resulted in improved therapeutic effect yielding an extended animal survival, compared with i.p. treatment with H-1PV alone. IFN? application enhanced the H-1PV-induced peritoneal macrophage and splenocyte responses against tumor cells while causing a significant reduction in the titers of H1-PV-neutralising antibodies in ascitic fluid. Thus, IFN? co-application together with H-1PV might be considered as a novel therapeutic option to improve the survival of PDAC patients with peritoneal carcinomatosis.
To define the matrilineal relationships between Bulgarians and other European populations, we have evaluated the mitochondrial DNA (mtDNA) variation in a sample of 855 Bulgarian subjects from the mtDNA perspective. The molecular survey was performed by sequencing ?750 bp of the control region, which resulted in 557 different haplotypes, and by a subsequent restriction fragment length polymorphism analysis to confirm haplogroup/subhaplogroup affiliation. The classification was carried out according to the most updated criteria as reported by van Oven and Kayser (Hum Mutat 30:386-394, 2009), allowing the identification of 45 mitochondrial clades. The observed pattern of mtDNA variation indicates that the Bulgarian mitochondrial pool is geographically homogeneous across the country, and that is characterized by an overall extremely high frequency of western Eurasian lineages. In the principal component analysis, Bulgarians locate in an intermediate position between Eastern European and Mediterranean populations, which is in agreement with historical events. Thus, while the Mediterranean legacy could be attributed to the Thracians, indigenous people that firstly inhabited the Balkans, the Eastern contribution is likely due to the Proto-Bulgarians originating from the Middle East and to the Slavs migrating from northeast Europe.
This review explores the application of the Simplex representation of molecular structure (SiRMS) QSAR approach in antiviral research. We provide an introduction to and description of SiRMS, its application in antiviral research and future directions of development of the Simplex approach and the whole QSAR field. In the Simplex approach every molecule is represented as a system of different simplexes (tetratomic fragments with fixed composition, structure, chirality and symmetry). The main advantages of SiRMS are consideration of the different physical-chemical properties of atoms, high adequacy and good interpretability of models obtained and clear procedures for molecular design. The reliability of developed QSAR models as predictive virtual screening tools and their ability to serve as the basis of directed drug design was validated by subsequent synthetic and biological experiments. The SiRMS approach is realized as the complex of the computer program HiT QSAR, which is available on request.
New acyclovir esters with peptidomimetics were synthesized and evaluated in vitro for their antiviral activity against the replication of Herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2). The influence of peptidomimetics containing oxazole and thiazolyl-thiazole moieties on the antiviral activity is also reported. The esters were synthesized using the coupling reagents N-ethyl-N-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N,N-dimethyl-4-aminopyridine (DMAP) as a catalyst.
The synthesis and the biological (antioxidant and antiviral) activities of novel hydroxycinnamic acid amides of a thiazole containing TFA.valine-4-carboxylic acid ethyl ester are reported. The amides have been synthesized from p-coumaric, ferulic and sinapic acids with the corresponding TFA.valine-thiazole-4-carboxylic acid ethyl ester using the coupling reagent N-ethyl-N-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and 4-(dimethylamino) pyridine (DMAP) as a catalyst. The antioxidant properties of the newly synthesized amides have been studied for then antioxidative activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH)* test. The newly synthesized compounds have been tested against the replication in vitro of influenza virus A (H3N2) and human herpes virus 1 and 2 (HSV-1 and HSV-2).
Molluscan hemocyanins (Hcs) have recently received particular interest due to their significant immunostimulatory properties. This is mainly related to their high carbohydrate content and specific monosaccharide composition. We have now analyzed the oligosaccharides and the carbohydrate linkage sites of the Rapana venosa hemocyanin (RvH) using different approaches. We analyzed a number of glycopeptides by LC/ESI-MS/MS and identified the sugar chains and peptide sequences of 12 glycopeptides. Additionally, the potential carbohydrate linkage sites of 2 functional units, RvH-b and RvH-c, were determined by gene sequence analysis. Only RvH-c shows a potential N-glycosylation site. During this study, we discovered a highly conserved linker-intron, separating the coding exons of RVH-b and RvH-c. Following reports on antiviral properties from arthropod hemocyanin, we conducted a preliminary study of the antiviral activity of RvH and the functional units RvH-b and RvH-c. We show that the glycosylated FU RvH-c has antiviral properties against the respiratory syncytial virus (RSV), whereas native RvH and the nonglycosylated FU RvH-b have not. This is the first report of the fact that also molluscan hemocyanin functional units possess antiviral activity.
Current study presents a novel scheme for combined application of anti-enteroviral substances in coxsackievirus B1 neuroinfection in newborn mice. It consists of a consecutive alternating, not simultaneous, administration of the substances in combination. A triple combination showing good efficacy was selected as a result of a screening of double, triple and quadruple combinations of enteroviral inhibitors. Its effectiveness is expressed in lengthening of the mean survival time and about 50% reduction of mortality rate in infected newborns as compared both to the placebo group, individual compounds used alone every day, and to the same combination applied simultaneously every day. Chronology of alternation of the individual drug administration plays a key role in the efficacy of the combination. Studies of the drug sensitivity of viral brain isolates from mice, treated with the drug combination indicate that virus isolates from the group treated with the alternating combination not only preserve, but even increase their sensitivity to the drugs. MIC(50) values of virus isolates from groups treated with monotherapies of the compounds manifested development of drug resistance. Obviously, the consecutive alternating administration of anti-enteroviral substances hinders the occurrence of drug resistance in the course of experimental coxsackievirus B1 infection in mice.
The incidence of lymphomas developing in both immunocompetent and immunosuppressed patients continues to steadily increase worldwide. Current chemotherapy and immunotherapy approaches have several limitations, such as severe side toxicity and selection of resistant cell variants. Autonomous parvoviruses (PVs), in particular the rat parvovirus H-1PV, have emerged as promising anticancer agents. Although it is apathogenic in humans, H-1PV has been shown to infect and suppress various rat and human tumors in animal models. In this study, we demonstrate the capacity of H-1PV for efficiently killing, through necrosis, cell cultures originating from Burkitts lymphoma (BL), while sparing normal B lymphocytes. The cytotoxic effect was generally accompanied by a productive H-1PV infection. Remarkably, parvovirus-based monotherapy efficiently suppressed established BL at an advanced stage in a severe combined immunodeficient (SCID) mouse model of the disease. The data show for the first time that an oncolytic parvovirus deserves further consideration as a potential tool for the treatment of some non-Hodgkin B-cell lymphomas, including those resistant to apoptosis induction by rituximab.
The combined effect of rimantadine and oseltamivir in a prophylactic context (therapy beginning 4 h pre-virus infection) and therapeutic context (therapy started at 24 h post-viral inoculation) course on influenza H3N2 virus infection in mice was studied. In the prophylactic course 5 and 10 mg/kg/day rimantadine with 0.2 and 0.4 mg/kg/day (25:1 dose ratio) oseltamivir showed a protection index (PI) of 79.6% and 75%, respectively and a mean survival time (MST) of 13.1 and 12.9 days. The individual effects of the same doses ranged from 0% to 33.3% PI and 8.2 to 10.3 days MST, respectively. Lung virus titers were decreased 630-fold in the combination-treated groups as compared to monotherapy and placebo groups. The reduction of surface lung pathology in combination-treated groups demonstrated a protective effect for the combination of both antivirals. In the therapeutic course 5 and 10 mg/kg rimantadine combined with 0.2 and 0.4 mg/kg oseltamivir showed no beneficial effect. At higher dosage (0.8, 1.6, 3.2 mg/kg oseltamivir and 20, 40, 80 mg/kg rimantadine) preserving the 25:1 ratio, the resultant PI ranged from 57.6% to 80.5% and the MST was 12.8-13.4 days. Used alone at the same doses the compounds protection varied between 10.7% and 71.8% PI, MST 9.8-12.8 days (8.7 days in PBS control). Compared to vehicle and individual treatment, a decrease in infectious viral titers of up to 1000-fold and other viral pneumonia parameters were also recorded. The therapeutic effect of the drugs optimal effective doses combinations was characterized as synergistic. Survival of animals was 81.2-100% and MST was extended by 5-7 days compared to placebos. Monotherapy protection was from 9.1% to a maximum of 56.5%, MST being prolonged only by 1.3-4.2 days compared to 7.5 days in the PBS control group. Lung viral titers were decreased 1445-fold for the most efficacious combination groups and a significant reduction in lung parameters was observed. These data emphasize that prophylactic and therapeutic courses using a combination of oseltamivir and rimantadine have a significant protective effect in mice experimentally infected with drug-sensitive influenza virus A (H3N2).
The phytochemical investigation of the aerial parts of Papaver pseudocanescens M. Pop. of Mongolian origin resulted in the isolation and structural elucidation of 8 alkaloids of the isoquinoline and promorphinane type. 8,14-Dihydroamurine, 8,14-dihydroflavinantine, and flavinantine are promorphinanes. Alborine, mecambridine, and mecambridine methohydroxide are retroprotoberberines. Amurensinine is an isopavine alkaloid and O-methylarmepavine is a benzylisoquinoline alkaloid. O-Methylarmepavine is a new alkaloid for the genus Papaver. Promorphinane-type alkaloids have been found for the first time in the species. All structures were established by physical and spectral analysis. As a first attempt to describe some of the biological activities of these alkaloids, the antiviral effect was tested against the in vitro replication of several viruses which belong to different taxonomic groups and represent significant human pathogens. Based on the results, the conclusion could be drawn that particular alkaloids from P. pseudocanescens possess selective antiviral effects against the replication of poliovirus 1 and human rhinovirus 14, two viruses from the Enterovirus genus of the Picornaviridae family.
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