Aспекты методики выделения коллагена

Laboratory of Tissue Engineering and Cells Cultures and Laboratory of Biochemistry, Nicolae Testemitanu State Medical and Pharmaceutical University, ChisinauBecause of the extreme diversity of tissues and types of collagen’ it is difficult to develop a standard method of extraction for all types of collagen from different tissues. Two procedures based on acid- and enzymatic-soluble collagen isolation were combined and offer some advantages and disadvantages to methods used in the present. Our results have demonstrated relatively low concentrations of collagen in the final solutions. There is 4.7 mg/ml from theoretically 10 mg/ml of acid-soluble fraction of collagen. This article describes some advantages and disadvantages of this isolation method. Due to the importance of biocompatible matrices for biomedical tissue engineering, the availability of native collagen should be studied by refining the extraction procedure of collagens. По причине чрезвычайного разнообразия тканей и типов коллагена содержащиеся в них, сложно разработать унифицированный метод получения коллагена. Были объединены две процедуры выделения коллагена, основанных на кислотном и ферментном растворении коллагена животного происхождения. Наши результаты показали относительно невысокие концентрации коллагена в конечном растворе, что составляет 4,7 мг/мл кислото-растворимого коллагена из теоретически возможных 10 мг/мл. В статье описаны некоторые преимущества и недостатки существующих методов. Разработка методов выделения коллагена первого типа важна по причине его использования для получения биосовместимых матриц и их применения в тканеинженерных конструкциях

New coins from old, smoothly

Given a (known) function $f:[0,1] \to (0,1)$, we consider the problem of simulating a coin with probability of heads $f(p)$ by tossing a coin with unknown heads probability $p$, as well as a fair coin, $N$ times each, where $N$ may be random. The work of Keane and O'Brien (1994) implies that such a simulation scheme with the probability $\P_p(N<\infty)$ equal to 1 exists iff $f$ is continuous. Nacu and Peres (2005) proved that $f$ is real analytic in an open set $S \subset (0,1)$ iff such a simulation scheme exists with the probability $\P_p(N>n)$ decaying exponentially in $n$ for every $p \in S$. We prove that for $\alpha>0$ non-integer, $f$ is in the space $C^\alpha [0,1]$ if and only if a simulation scheme as above exists with $\P_p(N>n) \le C (\Delta_n(p))^\alpha$, where \Delta_n(x)\eqbd \max \{\sqrt{x(1-x)/n},1/n \}. The key to the proof is a new result in approximation theory: Let \B_n be the cone of univariate polynomials with nonnegative Bernstein coefficients of degree $n$. We show that a function $f:[0,1] \to (0,1)$ is in $C^\alpha [0,1]$ if and only if $f$ has a series representation $\sum_{n=1}^\infty F_n$ with F_n \in \B_n and $\sum_{k>n} F_k(x) \le C(\Delta_n(x))^\alpha$ for all $x \in [0,1]$ and $n \ge 1$. We also provide a counterexample to a theorem stated without proof by Lorentz (1963), who claimed that if some \phi_n \in \B_n satisfy $|f(x)-\phi_n(x)| \le C (\Delta_n(x))^\alpha$ for all $x \in [0,1]$ and $n \ge 1$, then $f \in C^\alpha [0,1]$.Comment: 29 pages; final version; to appear in Constructive Approximatio

Cтволовые клетки в стоматологии будущего

Tooth loss compromises human oral health. Although several prosthetic methods (such as artificial denture and dental implants) are clinical therapies to tooth loss problems, they are thought to have safety and usage-time issues. Recently, tooth tissue engineering has attracted more and more attention. Stem cell based tissue engineering is thought to be a promising way to replace the missing tooth. Mesenchymal stem cells (MSC) are multipotent stem cells which can differentiate into a variety of cell types. The potential MSC for tooth regeneration mainly include stem cells from human exfoliated deciduous teeth, adult dental pulp stem cells, stem cells from the apical part of the papilla, stem cells from the dental follicle, periodontal ligament stem cells and bone marrow-derived mesenchymal stem cells. This review outlines the recent progress in mesenchymal stem cell research and its use in tooth regeneration and oral and craniofacial applications.Потеря зубов ставит под угрозу человеческое здоровье. Ткани зуба у взрослых практически не способны к самостоятельной регенерации и дефект эмали, возникающий в результате действия повреждающих факторов, постепенно приводит к потере зуба. Без сомнения, современные технологии протезирования позволяют произвести реконструкцию даже при полном отсутствии зубов. Однако прогресс современной органотипической регенеративной медицины заставляет исследователей искать новые технологии замещения зубов естественными трансплантатами. Последнее время клеточная инженерия тканей зуба привлекает все больше и больше внимания. Стволовые клетки являются многообещающим способом замены недостающего зуба. Мезенхимальные стволовые клетки способны дифференцироваться в клетки костной ткани, что дает возможность использовать их для восстановления зуба. Этот обзор рассматривает современные исследования стволовых клеток и возможность их использования для стимуляции репаративной регенерации тканей зуба

Surgical management of the general disease of burned children with skin allografts. A surgical perspective

Catedra chirurgie, ortopedie și anesteziologie pediatrică, USMF „Nicolae Testemițanu”, Clinica Arsuri și Chirurgie Plastică, IMC, Laborator Inginerie tisulară și culturi celulare, Chișinău, Republica Moldova, Conferința stiințifică „Nicolae Anestiadi – nume etern al chirurgiei basarabene” consacrată centenarului de la nașterea profesorului Nicolae Anestiadi 26 august 2016Introducere. Tehnicele chirurgicale au un rol important în managementul arsurilor majore la copii. Totodată sunt necesare inovaţii în tratamentul leziunilor termice. Utilizarea cu alopielei reduce la minimum închiderea plăgii și asocierea cicatrizării inestetice. Pentru arsurile profunde de gradul IIIB și IV unicul tratamentul care permite salvarea vieții copilului ars este excizia integrală de urgență a tegumentelor arse și acoperirea cu grefe de piele – alopielea. Materiale şi metode. În IMSP IMC, Clinica „Emilian Cоţaga”, secţia combustii şi chirurgie plastică reparatorie a fost efectuat pentru prima dată, în 2014, transplantul de allopiele la copiii cu arsuri. Allotransplantarea a fost efectuată la 40 copii cu vârsta între 1 şi 7 ani. Indicaţii pentru efectuarea transplantării de allopiele conservată în tratamentul arsurilor au servit: 1) arsurile extinse II- IIIA (peste 8-10%); 2) arsurile profunde (gradul IIIB) pe o suprafaţă de peste 15-20% din suprafaţa corpului; 3) lipsa de resurse a zonelor donatoare de piele; 4) imposibilitatea de transplant autolog simultan a pielii datorită severităţii stării pacientului; 5) acoperire temporară între etapele de transplantare a autopielii; 6) în timpul pregătirii plăgilor granulante. Rezultate şi discuţii. La transplantare au fost luate în consideraţie următoarele indicaţii: starea generală și vârsta copilului, suprafaţa leziunilor, localizarea arsurilor profunde, prezenţa resurselor donatorii proprii. Concluzii. La pacienții cu utilizarea alopielii sunt obţinute următoarele efecte: închiderea fiziologică a plăgilor, scăderea invaziei microbiene prin plagă, a pierderilor hidrice, proteice, electrolitice, a sindromului algic şi cât și a termenului pregătirii plăgilor postcombustionale pentru autotransplantare, accelerarea epitelizării plăgilor în arsurile de gradul IIIA.Background. Surgical techniques have an important role in the management of major burns in children. However, in the treatment of thermal injuries, innovations are needed. The use of alloskin allow a faster wound closure and minimizes unsightly scarring. In deep burns of IIIB and IV degree the only treatment that enables to save the burned child's life is full excision of the burnt skin and rapid coverage with skin grafts - alloskin. Materials and methods. In "Emilian Cоţaga" burns and reconstructive plastic surgery department skin allografts in burned children were used for the first time in 2014. Wound coverage with skin allografts was performed in 40 children aged between 1 and 7 years.Indications for making transplantation of preserved skin allografts in the treatment of burns served: 1) II-IIIA extensive burns (more than 8-10%); 2) deep burns (IIIB) of more than 15-20% of the body surface; 3) lack of resources of skin donor areas; 4) failure of autologous transplantation of the skin at the same time due to the severity of a patient; 5) temporary coverage between stages transplantation of own skin; 6) during the preparation of granulated wound. Results and discussions. During the transplantation the following were taken into consideration: child's age and general condition, the surface of injuries, deep burns location, presence of the own skin resources. Conclusion. By using skin allografts the following effects are obtained: physiological close of the wounds, decreased microbial invasion of the wound, decrease of loss of water, protein, electrolyte, pain syndrome, as well as the decrease of time needed for wound bed preparation for aulogus skin transplantation, accelerate wounds epithelization in partial thickness burns

Automated information system as quality management providing human tissue banks

School of Management, Nicolae Testemitsanu State University of Medicine and Pharmacy, Info World Company, Laboratory of Tissue Engineering and Cell Cultures, Bank of Human TissuesBackground: Modern tissue bank should have management autonomy, to be equipped with modern equipment for tissue grafts procurement, processing, preservation and storage that met the requirements of the profile structures of the EU Directives and Authorized National Health Services. Material and methods: Article represents the analysis of the needs to create and use in human tissues and cells bank an automated information system (AIS) to provide qualitative and safe tissue and cells grafts for transplantation in the Republic of Moldova. Automated Information System components are analyzed and characterized, elucidated the functions they have to fulfill, their role in ensuring the effective management of human tissue bank (HTB) in providing secure grafts for health system in the Republic of Moldova. Results: Basic functions of the HTB AIS include: management of the life cycle of donated products; information about products recording and storing; grafts records and relevant information about them; monitoring of the stored products; indexing exactly the products location in storage devices; a comprehensive view of patient information products; listing information in real and historical time by textual and graphical means; generating and scanning labels for each product; evidence of testing and validation samples; view reports using aggregate data; restricting access rights per each group of users. Conclusions: Thus it appears that AIS is an important element in ensuring a strict accounting of human allergic graft throughout their movement from the procurement, processing, validation, storage, distribution and transplantation. AIS also permits easier integration into the European network for tissue, because it allows encoding of grafts according to European unique codes way enabling the identification of tissue grafts as Bank products and follow their path. The computerized record of practical grafts excludes human errors in grafts distribution

Southern Europeans in France: Invisible Migrants?

France fared relatively well at the start of the current economic crisis, but has experienced low economic growth and high unemployment rates in the recent years. As a result it has been a less popular destination with Southern Europeans and EU migrants in general in search of economic opportunities. Although their numbers have increased and represent a growing proportion of recent flows to France, they remain low compared to numbers observed in Germany and the UK. Despite this statistical reality, EU mobility and more generally the role of the EU in economic and social policy have been at the forefront of debates in France since the start of the 2000s, thus well before the start of the crisis. These debates have focused on two populations – the Roma and posted workers – with both groups being portrayed as threats to the French welfare state. Although posted workers are not migrants, according to official EU definitions, their characteristics and experiences are similar to other groups of temporary migrant workers. Southern Europeans account for an increasing number of posted workers, and although they have not been the primary nationalities targeted in discussions concerning this issue, the debates and policy changes introduced in the recent years concern them as well. Moreover, we argue that the focusing of political debates on other populations in France has contributed to the relative invisibility of Southern European immigrants in this country

Global modeling of transcriptional responses in interaction networks

Motivation: Cell-biological processes are regulated through a complex network of interactions between genes and their products. The processes, their activating conditions, and the associated transcriptional responses are often unknown. Organism-wide modeling of network activation can reveal unique and shared mechanisms between physiological conditions, and potentially as yet unknown processes. We introduce a novel approach for organism-wide discovery and analysis of transcriptional responses in interaction networks. The method searches for local, connected regions in a network that exhibit coordinated transcriptional response in a subset of conditions. Known interactions between genes are used to limit the search space and to guide the analysis. Validation on a human pathway network reveals physiologically coherent responses, functional relatedness between physiological conditions, and coordinated, context-specific regulation of the genes. Availability: Implementation is freely available in R and Matlab at http://netpro.r-forge.r-project.orgComment: 19 pages, 13 figure

An Integrative -omics Approach to Identify Functional Sub-Networks in Human Colorectal Cancer

Emerging evidence indicates that gene products implicated in human cancers often cluster together in “hot spots” in protein-protein interaction (PPI) networks. Additionally, small sub-networks within PPI networks that demonstrate synergistic differential expression with respect to tumorigenic phenotypes were recently shown to be more accurate classifiers of disease progression when compared to single targets identified by traditional approaches. However, many of these studies rely exclusively on mRNA expression data, a useful but limited measure of cellular activity. Proteomic profiling experiments provide information at the post-translational level, yet they generally screen only a limited fraction of the proteome. Here, we demonstrate that integration of these complementary data sources with a “proteomics-first” approach can enhance the discovery of candidate sub-networks in cancer that are well-suited for mechanistic validation in disease. We propose that small changes in the mRNA expression of multiple genes in the neighborhood of a protein-hub can be synergistically associated with significant changes in the activity of that protein and its network neighbors. Further, we hypothesize that proteomic targets with significant fold change between phenotype and control may be used to “seed” a search for small PPI sub-networks that are functionally associated with these targets. To test this hypothesis, we select proteomic targets having significant expression changes in human colorectal cancer (CRC) from two independent 2-D gel-based screens. Then, we use random walk based models of network crosstalk and develop novel reference models to identify sub-networks that are statistically significant in terms of their functional association with these proteomic targets. Subsequently, using an information-theoretic measure, we evaluate synergistic changes in the activity of identified sub-networks based on genome-wide screens of mRNA expression in CRC. Cross-classification experiments to predict disease class show excellent performance using only a few sub-networks, underwriting the strength of the proposed approach in discovering relevant and reproducible sub-networks

FusionFinder: A Software Tool to Identify Expressed Gene Fusion Candidates from RNA-Seq Data

The hallmarks of many haematological malignancies and solid tumours are chromosomal translocations, which may lead to gene fusions. Recently, next-generation sequencing techniques at the transcriptome level (RNA-Seq) have been used to verify known and discover novel transcribed gene fusions. We present FusionFinder, a Perl-based software designed to automate the discovery of candidate gene fusion partners from single-end (SE) or paired-end (PE) RNA-Seq read data. FusionFinder was applied to data from a previously published analysis of the K562 chronic myeloid leukaemia (CML) cell line. Using FusionFinder we successfully replicated the findings of this study and detected additional previously unreported fusion genes in their dataset, which were confirmed experimentally. These included two isoforms of a fusion involving the genes BRK1 and VHL, whose co-deletion has previously been associated with the prevalence and severity of renal-cell carcinoma. FusionFinder is made freely available for non-commercial use and can be downloaded from the project website (http://bioinformatics.childhealthresearch.org.au/software/fusionfinder/)

High Accordance in Prognosis Prediction of Colorectal Cancer across Independent Datasets by Multi-Gene Module Expression Profiles

A considerable portion of patients with colorectal cancer have a high risk of disease recurrence after surgery. These patients can be identified by analyzing the expression profiles of signature genes in tumors. But there is no consensus on which genes should be used and the performance of specific set of signature genes varies greatly with different datasets, impeding their implementation in the routine clinical application. Instead of using individual genes, here we identified functional multi-gene modules with significant expression changes between recurrent and recurrence-free tumors, used them as the signatures for predicting colorectal cancer recurrence in multiple datasets that were collected independently and profiled on different microarray platforms. The multi-gene modules we identified have a significant enrichment of known genes and biological processes relevant to cancer development, including genes from the chemokine pathway. Most strikingly, they recruited a significant enrichment of somatic mutations found in colorectal cancer. These results confirmed the functional relevance of these modules for colorectal cancer development. Further, these functional modules from different datasets overlapped significantly. Finally, we demonstrated that, leveraging above information of these modules, our module based classifier avoided arbitrary fitting the classifier function and screening the signatures using the training data, and achieved more consistency in prognosis prediction across three independent datasets, which holds even using very small training sets of tumors