Universal thermal climate index in the Arctic in an era of climate change: Alaska and Chukotka as a case study.

The modern unambiguous climate change reveals in a rapid increase of air temperature, which is more distinctly expressed in the Arctic than in any other part of the world, affecting people health and well-being. The main objective of the current research is to explore the inter- and intra-annual changes in thermal stress for people in the Arctic, specifically for two parts of Beringia: Alaska, USA, and Chukotka, Russia, using climatology of the universal thermal climate index (UTCI). Data for 39 locations are taken from the ERA5-HEAT reanalysis for the period 1979-2020. Climatologically, the study area is divided into four subregions in Alaska: North, Interior, West and South, and two in Chukotka: Interior and Coast. The extreme coldest UTCI categories (1 and 2) are most common in coastal locations of northern Alaska and Chukotka, where strong winds exacerbate the low temperatures during winter. The results show that the frequency of category 1 (UTCI<-40°C) varies spatially from a quarter of all hours annually in Alaska North to almost zero in Alaska South. On the other hand, the warmest categories are rarely reached almost everywhere in Alaska and Chukotka, and even categories 7 and 8 (UTCI between +26 and +38°C) are found occasionally only at interior locations. Category 6 with no thermal stress (UTCI between +9 and+26°C) has frequencies up to 3% and 25% in Alaska North and Interior, respectively. The extremely cold thermal stress frequencies have substantially decreased over the 1979-2020 period, especially in Alaska North and Chukotka Coast. At the same time, the number of hours with UTCI in the comfortable category of thermal perception has increased depending on subregion, from 25 to 203 h/year. Overall, a decrease in the UTCI categories of extremely cold stress is coupled with an increase in the comfortable range in both Alaska and Chukotka. The salient conclusion is that, from the point of view of comfort and safety, global warming has a positive impact on the climatology of thermal stress in the Arctic, providing advantages for the development of tourism and recreation.

[Intraoperative intraperitoneal chemoperfusion treatment with cisplatin and dioxadet on a model of peritoneal carcinomatosis in ovarian cancer: safety and efficacy evaluation].

A comparative study of safety and efficacy of normothermic and hyperthermic intraperitoneal chemoperfusion (IPEC and HIPEC) with cisplatin and dioxadet was carried out in 143 female Wistar rats. Ovarian cancer was inoculated intraperitoneally (i.p.). In 48 hours after ovarian cancer inoculation the drugs were administered i.p. or IPEC and HIPEC with the drugs were performed using maximum tolerated doses (MTD). Content of cisplatin was determined in the perfusate and blood plasma during HIPEC with the drug. The leukocyte count was measured using veterinary hematologic analyzer in peripheral blood of rats at different time points after HIPEC with dioxadet. Efficacy of the treatment was estimated in increase in median survival time (MST). During HIPEC cisplatin was accumulated in the abdominal cavity in a considerable amount with minimal systemic absorption. HIPEC with dioxadet didn't significantly affect the leukocyte count in peripheral blood while i.p. administration of dioxadet suppressed leukopoiesis. MST of rats after IPEC with cisplatin was 37.5 days which was significantly higher compared to MST after i.p. administration of cisplatin (19.5 days, p = 0.037). HIPEC with dioxadet was the most effective regimen of treatment with MST of rats reaching 49 days which was significantly higher compared to MST after HIPEC with cisplatin (25.5 days, p = 0.002).

[CHEMOPERFUSION TECHNOLOGIES IN TREATMENT FOR MALIGNANT TUMORS].

The data of literature on possibility of the use of perfusion technologies in combined treatment for malignant tumors of different sites are presented. Possible complications during hyperthermic chemoperfusion are discussed and the effectiveness of this method is analyzed.

Immunotargeting and eradication of orthotopic melanoma using a chemokine-enhanced DNA vaccine.

DNA vaccines are attractive candidates for tumor immunotherapy. However, the potential of DNA vaccines in treating established malignant lesions has yet to be demonstrated. Here we demonstrate that transient alteration of either intratumoral or intradermal (ID) chemotactic gradients provide a favorable milieu for DNA vaccine-mediated activation of tumor-specific immune response in both prophylactic and therapeutic settings. Specifically, we show that priming of established B16 ID melanoma lesions via forced intratumoral expression of CCL21 boosted DNA vaccination-dependent systemic cytotoxic immune response leading to the regression of tumor nodules. In this setting, application of CCL20 was not effective likely due to the engagement of the regulatory T cells. However, priming of the skin at DNA vaccine administration sites outside the tumor bed with both CCL20 and CCL21 chemokines along with structural modifications of the DNA vaccine significantly improved vaccine efficacy. This optimized ID vaccination regimen led to the inhibition of distant established melanomas and prolonged tumor-free survival of mice observed in 60% of vaccinated animals with complete tumor remission in 30%. These effects were mediated by extranodal priming and activation of T cells at vaccine administration sites and progressive accumulation of systemic antigen-specific cytotoxic T cells (CTLs) on successive vaccinations. These results underscore the potential of chemokine-enhanced DNA vaccination to mount therapeutic immune response against established tumors.

MicroRNA-dependent regulation of cKit in cutaneous melanoma.

Loss of cKit receptor in cutaneous melanomas was attributed to the down-regulation of AP2 transcription factor. Our analysis of 27 melanoma cell lines showed no correlation between AP2 and c-kit expression. Suggesting a post-transcriptional mechanism of cKit down-modulation, we performed genome-wide microRNA (miRNA) expression profiling and found that several miRNA species are commonly up-regulated in melanomas. Among them was mir-221, which can directly interact with c-kit 3'UTR and inhibit cKit protein translation. Observed inverse correlation of the c-kit and mir-221 expression in various melanocytic cells pointed to its involvement in regulation of cKit in melanoma. Moreover, a series of functional assays demonstrated that mir-221 could directly inhibit cKit, p27(Kip1) and, possibly, other pivotal proteins in melanoma. Collectively, the studies presented here indicate that mir-221 could be a novel therapeutic target for the treatment of cutaneous melanoma. They also suggest that regulation of expression and functional activity of identified up-regulated miRNAs should be further studied in the context of malignant melanoma.

Site-specific gene modification by oligodeoxynucleotides in mouse bone marrow-derived mesenchymal stem cells.

Synthetic oligodeoxynucleotides (ODNs) had been employed in gene modification and represent an alternative approach to 'cure' genetic disorders caused by mutations. To test the ability of ODN-mediated gene repair in bone marrow-derived mesenchymal stem cells (MSCs), we established MSCs cell lines with stably integrated mutant neomycin resistance and enhanced green fluorescent protein reporter genes. The established cultures showed morphologically homogenous population with phenotypic and functional features of mesenchymal progenitors. Transfection with gene-specific ODNs successfully repaired targeted cells resulting in the expression of functional proteins at relatively high frequency approaching 0.2%. Direct DNA sequencing confirmed that phenotype change resulted from the designated nucleotide correction at the target site. The position of the mismatch-forming nucleotide was shown to be important structural feature for ODN repair activity. The genetically corrected MSCs were healthy and maintained an undifferentiated state. Furthermore, the genetically modified MSCs were able to engraft into many tissues of unconditioned transgenic mice making them an attractive therapeutic tool in a wide range of clinical applications.

Immunotherapeutic strategies for the treatment of malignant melanoma.

The incidence of cutaneous malignant melanoma is increasing at a faster rate than any other cancer worldwide. Despite new advances in surgical management of melanoma, this malignancy remains one of the most aggressive and intractable to treat among other solid tumors. Continuous search for better therapeutics led to the development of various immunological approaches applicable to the treatment of this melanocytic malignancy. Multiple peptide, dendritic cell, adjuvant, lymphocyte, and virus-based strategies were established and tested in preclinical and clinical studies with varying degrees of clinical success. However, the most recent investigations in melanoma immunotherapy have clearly demonstrated that complex vaccines and the combination of different approaches, such as the use of dendritic cell vaccines in conjunction with costimulatory molecules, are superior to conventional immunization protocols in induction of tumor-specific immune responses. These recent studies open new perspectives for the development of efficient melanoma immunotherapeutics suitable for the treatment of primary and metastatic disease.

Stable and inheritable changes in genotype and phenotype of albino melanocytes induced by an RNA-DNA oligonucleotide.

Experimental strategies have been developed to correct point mutations using chimeric oligonucleotides composed of RNA and DNA. We used these RNA-DNA oligonucleotides to correct a point mutation in mouse tyrosinase, a key enzyme for melanin synthesis and pigmentation. Melanocytes derived from albino mice contain a homozygous point mutation (TGT-->TCT) in the tyrosinase gene, resulting in an amino acid change from Cys-->Ser. Correction of this point mutation results in the restoration of tyrosinase activity and melanin synthesis, thus changing the pigmentation of the cells. Upon transfection of the RNA-DNA oligonucleotide to albino melanocytes, we detected black-pigmented cells and isolated multiple single clones. All black-pigmented clones exhibited a correction of the point mutation in a single allele of the tyrosinase gene. A full-length tyrosinase was detected by an antityrosinase antibody, and the enzymatic activity was restored in all converted black-pigmented clones. Only degraded fragments were detected in albino cells due to proteolytic cleavage of mutant tyrosinase. The phenotype and genotype of converted black-pigmented clones was stable. These results demonstrate a permanent and stable gene correction by the RNA-DNA oligonucleotide at the level of genomic sequence, protein, and phenotypic change by clonal analysis.

Localized in vivo genotypic and phenotypic correction of the albino mutation in skin by RNA-DNA oligonucleotide.

We recently demonstrated that an RNA-DNA oligonucleotide corrected a point mutation in the mouse tyrosinase gene, resulting in permanent and inheritable restoration of tyrosinase enzymatic activity, melanin synthesis, and pigmentation changes in cultured melanocytes. In this study, we extended gene correction of melanocytes from tissue culture to live animals, using a chimeric oligonucleotide designed to correct a point mutation in the tyrosinase gene. Both topical application and intradermal injection of this oligonucleotide to albino BALB/c mouse skin resulted in dark pigmentation of several hairs in a localized area. The restored tyrosinase enzymatic activity was detected by dihydroxyphenylacetic acid (DOPA) staining of hair follicles in the treated skin. Tyrosinase gene correction was also confirmed by restriction fragment length polymorphism analysis and DNA sequencing from skin that was positive for DOPA staining and melanin synthesis. Localized gene correction was maintained three months after the last application of the chimeric oligonucleotides. These results demonstrated correction of the tyrosinase gene point mutation by chimeric oligonucleotides in vivo.

Cardiovascular diseases in the Republic of Sakha (Yakutia): status of the problem in the light of scientific research results.

In the paper, dynamics of risk factors of cardiovascular diseases and their contribution to mortality rate in the male population of Yakutsk are analyzed according to the results of standardized epidemiological researches carried out in the period of 1986-2005. It was revealed that the unfavourable cardiovascular epidemiologic situation in Yakutia is caused by the prevalence of such risk factors as smoking, excess body weight and arterial hypertension.

Differential cellular responses to exogenous DNA in mammalian cells and its effect on oligonucleotide-directed gene modification.

Transient transfection has been widely used in many biological applications including gene regulation and DNA repair, but, so far, little attention has been paid to cellular responses induced by the transfected DNA. Here, we report that double-stranded (ds) DNA introduced into mammalian cells induced expression of a variety of genes involved in DNA damage signaling and DNA repair. The expression profile of the induced genes was highly dependent on the cell type, suggesting interactions between exogenous dsDNA and cellular proteins. Moreover, each cell line elicited a markedly different level of intrinsic cellular responses to the introduced dsDNA. Furthermore, the presence of single-stranded oligonucleotides or short duplexes consisting of two complementary oligonucleotides did not affect cellular response, indicating that the induction was highly dependent on the structure and length of exogenous DNA. The extent of induction of DNA damage, signaling and DNA repair activities correlated to episomal and chromosomal gene correction frequencies. In addition, the presented data indicate that the presence of exogenous dsDNA triggered a DNA damage response by activation of ATR (ataxia telangiectasia-Rad3-related) but not ATM (ataxia telangiectasia mutated) pathway.

Thinking in the old way and trying to live in the new.

Professor Viatcheslav Alexeev offers freelance journalist Sarah Powell his views of the state of the Russian national health system and the challenges faced as Russia moves from a socialist to a capitalist economy. Viatcheslav Alexeev is Professor of International Health and Management at the Department of International Health of the Russian Medical Academy of Advanced Medical Studies in Moscow. His wide-ranging experience includes teaching management and health administration, health manpower development, and interpersonal relationships at the Central Institute for Advanced Medical Studies. Following this, for over 20 years he was Assistant Professor and Director of the WHO International Courses for Health Administrators. From 1981 to 1987, he worked on the staff of the Health Manpower Development Division of the WHO in Geneva, in which capacity he gained extensive experience of training, research and organization in over 30 countries.

Gene correction by RNA-DNA oligonucleotides.

An oligonucleotide composed of a contiguous stretch of RNA and DNA residues has been developed to facilitate the correction of single-base mutations of episomal and chromosomal targets in mammalian cells. The design of the oligonucleotide exploited the highly recombinogenic RNA-DNA hybrids and featured hairpin capped ends avoiding destruction by cellular helicases or exonucleases. The RNA-DNA oligonucleotide (RDO) was designed to correct a point mutation in the tyrosinase gene and caused a permanent gene correction in mouse albino melanocytes, determined by clonal analysis at the level of genomic sequence, protein and phenotypic change. Recently, we demonstrated correction of the tyrosinase gene using the same RDO in vivo, as detected by dark pigmentation of several hairs and DOPA staining of hair follicles in the treated skin of albino mice. Such RDOs might hold a promise as a therapeutic method for the treatment of skin diseases. However, the frequency of gene correction varies among different cells, indicating that cellular activities, such as recombination and repair, may be important for gene conversion by RDOs. As this technology becomes more widely utilized in the scientific community, it will be important to understand the mechanism and to optimize the design of RDOs to improve their efficiency and general applicability.

Targeted gene correction by small single-stranded oligonucleotides in mammalian cells.

We demonstrate that relatively short single-stranded oligodeoxynucleotides, 25-61 bases homologous to the target sequence except for a single mismatch to the targeted base, are capable of correcting a single point mutation (G to A) in the mutant beta-galactosidase gene, in nuclear extracts, episome, and chromosome of mammalian cells, with correction rates of approximately 0.05%, 1% and 0.1%, respectively. Surprisingly, these short single-stranded oligonucleotides (ODN) showed a similar gene correction frequency to chimeric RNA-DNA oligonucleotide, measured using the same system. The in vitro gene correction induced by ODN in nuclear extracts was not dependent on the length or polarity of the oligonucleotide. In contrast, the episomal and chromosomal gene corrections were highly dependent on the ODN length and polarity. ODN with a homology of 45 nucleotides showed the highest frequency and ODN with antisense orientation showed a 1000-fold higher frequency than sense orientation, indicating a possible influence of transcription on gene correction. Deoxyoligonucleotides showed a higher frequency of gene correction than ribo-oligonucleotides of the identical sequence. These results show that a relatively short ODN can make a sequence-specific change in the target sequence in mammalian cells, at a similar frequency as the chimeric RNA-DNA oligonucleotide.

Simultaneous targeted alteration of the tyrosinase and c-kit genes by single-stranded oligonucleotides.

We have shown that various forms of oligonucleotides, chimeric RNA-DNA oligonucleotide (RDO) and single-stranded oligodeoxynucleotide (ODN), are capable of chromosomal gene alterations in mammalian cells. Using two ODNs we corrected an inactivating mutation in the tyrosinase gene and introduced an activating mutation into the c-kit gene in a single albino mouse melanocyte. Relying on a pigmentation change caused by tyrosinase gene correction, we determined the frequency of gene targeting events ranging from 2 x 10(-4) to 1 x 10(-3), which is comparable to our previously published data using RDO. However, ODN showed more reproducible gene correction than RDO and produced pigmented cells among 60% of experiments, in comparison with 10% by RDO. DNA sequence analysis of the converted cells revealed that two out of eight individual pigmented clones harbored the mutated c-kit gene. Targeted modification of both genes resulted in the ability of the tyrosinase to convert tyrosine to melanin, and in the constitutive activation of the Kit receptor kinase. Thus, for the first time, we demonstrate the feasibility of simultaneous targeting of two genes in a single cell and show that a selection strategy to identify cells that have undergone a gene modification can enrich the targeted cells with the desired gene alteration.

Autosomal dominant spinocerebellar ataxia (SCA) in a Siberian founder population: assignment to the SCA1 locus.

In seven families from a Siberian founder population with autosomal dominant spinocerebellar ataxia (SCA) genetic analysis of the polymorphisms flanking the SCA1 locus on chromosome 6p showed allelic association with disease inheritance. While the association was absolute in the case of microsatellite D6S274, an allele switch was observed for D6S89 in two families, suggesting a historic recombinant. Further genetic and physical study of this recombinant event could be instrumental for the precise localization and identification of the SCA1 gene.

Unstable triplet repeat and phenotypic variability of spinocerebellar ataxia type 1.

A Siberian kindred with spinocerebellar ataxia genetically linked to the SCA1 locus on chromosome 6p has been screened for the CAG triplet expansion within the coding region of the SCA1 gene. The kindred includes 1,484 individuals, 225 affected and 656 at risk, making this collection the largest spinocerebellar ataxia type 1 (SCA1) pedigree known. Each of the studied 78 SCA1 patients carried an expanded allele containing a stretch of 39 to 72 uninterrupted CAG repeats. Normal alleles had 25 to 37 trinucleotide repeats. Expanded alleles containing 40 to 55 repeats were found in 26 at-risk relatives. The number of CAG repeats in the mutated allele was inversely correlated with age at disease onset. Cerebellar deficiency was present in each patient and its severity was moderately affected by the number of CAG repeats. In contrast, the associated signs, dysphagia, diffuse skeletal muscle atrophy with fasciculations, and tongue atrophy were absent or mild in patients with low CAG repeat numbers, but severely complicated the course of illness in patients with a larger number of repeat units. One female mutation carrier was asymptomatic at age 66, more than 2 standard deviations beyond the average age of risk, suggesting incomplete penetrance. In 2 symptomatic individuals who had an expanded number of CAG repeats on both chromosomes, age at onset, rate of progression, and clinical manifestation corresponded to the size of the larger allele.