Commercial and Custom Quartz Tuning Forks for Quartz Enhanced Photoacoustic Spectroscopy: Stability under Humidity Variation.

This work investigates the behavior of commercial and custom Quartz tuning forkss (QTF) under humidity variations. The QTFs were placed inside a humidity chamber and the parameters were studied with a setup to record the resonance frequency and quality factor by resonance tracking. The variations of these parameters that led to a 1% theoretical error on the Quartz Enhanced Photoacoustic Spectroscopy (QEPAS) signal were defined.

Evaluation of encapsulating and microporous nondegradable hydrogel scaffold designs on islet engraftment in rodent models of diabetes.

Islet transplantation is a promising therapeutic option for type 1 diabetes mellitus, yet the current delivery into the hepatic portal vasculature is limited by poor engraftment. Biomaterials have been used as a means to promote engraftment and function at extrahepatic sites, with strategies being categorized as encapsulation or microporous scaffolds that can either isolate or integrate islets with the host tissue, respectively. Although these approaches are typically studied separately using distinct material platforms, herein, we developed nondegradable polyethylene glycol (PEG)-based hydrogels for islet encapsulation or as microporous scaffolds for islet seeding to compare the initial engraftment and function of islets in syngeneic diabetic mice.

Retrievable hydrogels for ovarian follicle transplantation and oocyte collection.

Cancer survivorship rates have drastically increased due to improved efficacy of oncologic treatments. Consequently, clinical concerns have shifted from solely focusing on survival to quality of life, with fertility preservation as an important consideration. Among fertility preservation strategies for female patients, ovarian tissue cryopreservation and subsequent reimplantation has been the only clinical option available to cancer survivors with cryopreserved tissue.

Primordial Follicle Transplantation within Designer Biomaterial Grafts Produce Live Births in a Mouse Infertility Model.

The gonadotoxic effects of chemotherapy and radiation may result in premature ovarian failure in premenopausal oncology patients. Although autotransplantation of ovarian tissue has led to successful live births, reintroduction of latent malignant cells inducing relapse is a significant concern. In this report, we investigated the design of biomaterial grafts for transplantation of isolated ovarian follicles as a means to preserve fertility.

[Influence of unilayered and multilayered liposomes containing fatty-acid complex Bien upon phagocyte activity in rat alveolar macrophages].

The phagocyte activity of rat alveolar macrophages and their primary culture under the interaction with liposomes containing unsaturated fatty acid complex Bien has been studied in vitro. Quantitative dependence of the phagocyte number and phagocyte factor on the liposomal Bien concentration were estimated. Comparative analysis of the effects of multilayered and unilayered liposomes with Bien upon cell suspension has been carried out.

Fibrin-mediated delivery of an ovarian follicle pool in a mouse model of infertility.

The cryopreservation and autotransplantation of ovarian tissue is emerging as a powerful approach for preserving fertility. However, for cancer patients, it may not be possible to transplant ovarian tissue due to the risk of re-seeding disease. We investigated strategies for transplantation of individually isolated follicles to minimize the risk of re-introducing cancer cells present within the vasculature of ovarian stroma.

Promoting extracellular matrix remodeling via ascorbic acid enhances the survival of primary ovarian follicles encapsulated in alginate hydrogels.

The in vitro growth of ovarian follicles is an emerging technology for fertility preservation. Various strategies support the culture of secondary and multilayer follicles from various species including mice, non-human primate, and human; however, the culture of early stage (primary and primordial) follicles, which are more abundant in the ovary and survive cryopreservation, has been limited. Hydrogel-encapsulating follicle culture systems that employed feeder cells, such as mouse embryonic fibroblasts (MEFs), stimulated the growth of primary follicles (70-80 µm); yet, survival was low and smaller follicles (<70 µm) rapidly lost structure and degenerated.

Dynamic transcription factor networks in epithelial-mesenchymal transition in breast cancer models.

The epithelial-mesenchymal transition (EMT) is a complex change in cell differentiation that allows breast carcinoma cells to acquire invasive properties. EMT involves a cascade of regulatory changes that destabilize the epithelial phenotype and allow mesenchymal features to manifest. As transcription factors (TFs) are upstream effectors of the genome-wide expression changes that result in phenotypic change, understanding the sequential changes in TF activity during EMT provides rich information on the mechanism of this process.

Transcription factor networks in invasion-promoting breast carcinoma-associated fibroblasts.

Carcinoma-associated fibroblasts (CAFs) contribute to both tumor growth and cancer progression. In this report, we applied an emerging transcription factor (TF) activity array to fibroblasts to capture the activity of the intracellular signaling network and to define a signature that distinguishes mammary CAFs from normal mammary fibroblasts. Normal fibroblasts that restrained cancer cell invasion developed into an invasion-promoting CAF phenotype through exposure to conditioned medium from MDA-MB-231 breast cancer cells.

Quantification of local matrix deformations and mechanical properties during capillary morphogenesis in 3D.

Reciprocal mechanical interactions between cells and the extracellular matrix (ECM) are thought to play important instructive roles in branching morphogenesis. However, most studies to date have failed to characterize these interactions on a length scale relevant to cells, especially in three-dimensional (3D) matrices. Here we utilized two complementary methods, spatio-temporal image correlation spectroscopy (STICS) and laser optical tweezers-based active microrheology (AMR), to quantify endothelial cell (EC)-mediated deformations of individual ECM elements and the local ECM mechanical properties, respectively, during the process of capillary morphogenesis in a 3D cell culture model.

Concentration independent modulation of local micromechanics in a fibrin gel.

Methods for tuning extracellular matrix (ECM) mechanics in 3D cell culture that rely on increasing the concentration of either protein or cross-linking molecules fail to control important parameters such as pore size, ligand density, and molecular diffusivity. Alternatively, ECM stiffness can be modulated independently from protein concentration by mechanically loading the ECM. We have developed a novel device for generating stiffness gradients in naturally derived ECMs, where stiffness is tuned by inducing strain, while local mechanical properties are directly determined by laser tweezers based active microrheology (AMR).

Effects of extracellular matrix density and mesenchymal stem cells on neovascularization in vivo.

Aberrant angiogenesis is common to a variety of diseases in which alterations in tissue mechanical properties also occur. A fundamental understanding of the interdependence of angiogenesis and tissue structural properties may enhance the development of therapeutic strategies. We previously established that increasing extracellular matrix density inhibits capillary morphogenesis in three-dimensional tissues in vitro, and that addition of human mesenchymal stem cells (MSCs) partially rescues a healthy angiogenic phenotype.

Recreating the perivascular niche ex vivo using a microfluidic approach.

Stem cell niches are composed of numerous microenvironmental features, including soluble and insoluble factors, cues from other cells, and the extracellular matrix (ECM), which collectively serve to maintain stem cell quiescence and promote their ability to support tissue homeostasis. A hallmark of many adult stem cell niches is their proximity to the vasculature in vivo, a feature common to neural stem cells, mesenchymal stem cells (MSCs) from bone marrow and adipose tissue, hematopoietic stem cells, and many tumor stem cells. In this study, we describe a novel 3D microfluidic device (MFD) as a model system in which to study the molecular regulation of perivascular stem cell niches.

Mesenchymal cells stimulate capillary morphogenesis via distinct proteolytic mechanisms.

During angiogenesis, endothelial cells (ECs) degrade their surrounding extracellular matrix (ECM) to facilitate invasion. How interactions between ECs and other cells within their microenvironment facilitate this process is only partially understood. We have utilized a tractable 3D co-culture model to investigate the proteolytic mechanisms by which pre-committed or more highly committed mesenchymal cells stimulate capillary formation.

Endothelial cell traction and ECM density influence both capillary morphogenesis and maintenance in 3-D.

Identifying the mechanisms regulating angiogenesis in pathological conditions such as cancer and heart disease is crucial to develop successful therapies. The dependence of angiogenesis on characteristic properties of these conditions, such as alterations in tissue stiffness due to changes in the composition of the extracellular matrix (ECM), may shed light on potential therapeutic strategies. Prior studies have suggested that ECM compliance regulates capillary morphogenesis, but the mechanisms remain unclear.

Identification and characterization of dynein genes in Tetrahymena.

We describe the protocol through which we identify and characterize dynein subunit genes in the ciliated protozoan Tetrahymena thermophila. The gene(s) of interest is found by searching the Tetrahymena genome, and it is characterized in silico including the prediction of the open reading frame and identification of likely introns. The gene is then characterized experimentally, including the confirmation of the exon-intron organization of the gene and the measurement of the expression of the gene in nondeciliated and reciliating cells.

[The structure of micromycete complexes in permafrost and cryopegs of the Arctic].

A comparative study of the structure of micromycete complexes has been performed. The samples of micromycetes were taken by boring from unique habitats: cryopegs (lenses of non-freezing hypersaline water in ancient permafrost horizons) and permafrost Arctic sediments of different age enclosing these cryopegs. The possibility of characterizing the above habitats by the structure of specific complexes of microscopic fungi using qualitative and quantitative indices at extremely low numbers of these organisms was demonstrated.

Dynein light chain family in Tetrahymena thermophila.

Dyneins are large protein complexes that produce directed movement on microtubules. In situ, dyneins comprise combinations of heavy, intermediate, light-intermediate, and light chains. The light chains regulate the locations and activities of dyneins but their functions are not completely understood.

[Experience in the use of flow scintillator Cobas Micros-18 OT in hematological practice].

Clinical analysis of the blood is a most prevalent investigation in practical medicine. The need in effective assessment of the results of blood analysis prompted the creation of automated flow systems. Our task was to analyze the blood of normal subjects and patients by Hoffmann La Roche Cobas Micros-18 OT (France).

[Flow cytometry in hematology. Methods and technique of flow cytometric analysis].

Reviews the history of flow cytometry, the philosophy of the method, main methods of cell investigation (conductometry, registration of light absorption and diffusion, cytofluorometry, study of fluorescence polarization, and analysis of a wave-shaped signal). Describes the equipment and methods for flow cytofluorometric analysis of cells, used in hematology. Characterizes the hematological analyzers with differentiated estimation of leukocytes.

[Neutrophil and macrophage functional activity during the irradiation of an intestinal anastomosis with a low-intensity laser in the infrared spectral range].

The influence of different methods of treatment of intestinal anastomosis in rabbits (group 1: common single-row sutures; group 2: sutures treated with cyanacrylate glue CO-4; group 3: low-intensity laser irradiation through the skin in the infrared spectral range) on the phagocytic and oxidase activity of cells in the peritoneal washings and peripheral blood on days 2, 4 and 7 after the operation was studied. Laser irradiation of the suture was shown to produce a stimulating effect on the macrophagal-phagocytic system of the blood. The oxidase activity of phagocytes in peritoneal washings in the group of animals subjected to laser irradiation was considerably lower than in two other groups.

[Clinico-pathogenetic substantiation of comprehensive therapy of Klebsiella infection with the syndrome of water diarrhea in infants].

The data on the examination of 70 infants with Klebsiella infection are presented. The patho-chemical disorders in the intestine under the action of Klebsiella were followed up in the time course and the adequacy of the pathogenetic therapy of the antiinflammatory and membrane protective destination was substantiated. The efficacies of the comprehensive therapy with the use of indomethacin, essential and dimephosphone and the therapy with antibacterial drugs such as monomycin, kanamycin, polymyxin and gentamicin administered orally were compared.

[The process of the persistence of Salmonella typhi L forms in the body of experimental animals studied by immunoradiometric analysis].

The use of the immunoradiometric assay made it possible to reveal a prolonged persistence of the antigen of viable cultures of S. typhi stable L-forms, as well as to study the dynamics of its spread in the body of experimental animals. After both subconjunctival and intraperitoneal infection of guinea pigs the antigen of S.