Vertical sections of cultivated anchorage-dependent cells for electron microscopy

A method is described for electron microscopic preparation of cultivated cells for vertical sections using the test chamber system TCSC-1. The cells are cultivated on a special foil. They can be fixed and embedded directly in the chamber. After polymerization of the resin, the foil can be easily taken off and a second resin layer is poured upon the embedded cells. Then distinct cells can be marked under an inverted light microscope. The bilayer of the resin allows optimal conditions for vertical sections of anchorage-dependent cells.     

Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties

Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates.     

An unsupervised learning method with a clustering approach for tumor identification and tissue segmentation in magnetic resonance brain images

Malignant and benign types of tumor infiltrated in human brain are diagnosed with the help of an MRI scanner. With the slice images obtained using an MRI scanner, certain image processing techniques are utilized to have a clear anatomy of brain tissues. One such image processing technique is hybrid self-organizing map (SOM) with fuzzy K means (FKM) algorithm, which offers successful identification of tumor and good segmentation of tissue regions present inside the tissues of brain. The proposed algorithm is efficient in terms of Jaccard Index, Dice Overlap Index (DOI), sensitivity, specificity, peak signal to noise ratio (PSNR), mean square error (MSE), computational time and memory requirement. The algorithm proposed through this paper has better data handling capacities and it also performs efficient processing upon the input magnetic resonance (MR) brain images. Automatic detection of tumor region in MR (magnetic resonance) brain images has a high impact in helping the radio surgeons assess the size of the tumor present inside the tissues of brain and it also supports in identifying the exact topographical location of tumor region. The proposed hybrid SOM-FKM algorithm assists the radio surgeon by providing an automated tissue segmentation and tumor identification, thus enhancing radio therapeutic procedures. The efficiency of the proposed technique is verified using the clinical images obtained from four patients, along with the images taken from Harvard Brain Repository.     

Biopolymer-based functional composites for medical applications

Over the last decade, numerous biopolymers have received more attention in medical applications involving novel biomaterials because of their biocompatibility, biodegradability, and ease of processing. To date, many biopolymer-based functional composites have been developed to increase the value of raw biopolymers obtained from natural sources or microbial systems. This review article covers general information on various biopolymers, important methods for biopolymer-based composites preparation including their advantages and disadvantages, and surface topography for tissue engineering. In addition, this article provides comprehensive knowledge and highlights recent research on functional biopolymer composites used in various medical applications, such as tissue engineering comprising skin, bone, cartilage, vascular graft, and other organs, implantable medical devices including stent and barrier membrane, and some delivery systems of bioactive agents. Furthermore, the article presents a brief overview on several challenges and future scope in this field.     

miR-181b promotes the oncogenesis of renal cell carcinoma by targeting TIMP3

Renal cell carcinoma (RCC) has a poor prognosis due to limited diagnosis and treatment. Thus, it is necessary to find novel prognostic biomarkers and therapeutic targets. The aberrant expression of microRNAs plays an important role in RCC oncogenesis. Tissue inhibitors of metalloproteinase 3 (TIMP3) acts as a downstream target of miR-181b. The aim of this study was to understand the role and molecular mechanism of miR-181b in RCC oncogenesis. The results showed that miR-181b expression was significantly higher in RCC tumour tissues, especially in those with significant invasion or metastasis. miR-181b overexpression promoted proliferation and migration of the RCC cell line 786-O, while miR-181b knockdown had the opposite effect. In addition, miR-181b was inversely correlated with TIMP3 expression in RCC tumour tissues. miR-181b overexpression reduced TIMP3 expression in RCC cell line 786-O or OS-RC-2, while miR-181b knockdown had the inverse effect. Mechanistically, a luciferase reporter assay confirmed the binding sites of miR-181b on the 3’-UTR of TIMP3, confirming the targeting effect of miR-181b on TIMP3. Overall, miR-181b promotes the development and progression of RCC by targeting TIMP3 expression, indicating the potential use of miR-181b in the diagnosis and treatment of RCC.     

Assessing the impact of palmitic,myristic and lauric acids on hydrogen production from glucose fermentation by mixed anaerobic granular cultures

The effects of lauric (LUA), myristic (MA), palmitic (PA), and a mixture of myristic:palmitic (MA:PA) acids on hydrogen (H₂) production from glucose degradation using anaerobic mixed cultures were assessed at 37 °C with an initial pH set at 5.0 and 7.131 mM of each acid. The maximum H₂ yield (2.53 ± 0.18 mol mol⁻¹ glucose) was observed in cultures treated with PA. A principal component analysis (PCA) of the by-products and the microbial population data sets detected similarities between the controls and PA treated cultures; however, differences were observed between the controls and PA treated cultures in comparison to the MA and LUA treated cultures. The flux balance analysis (FBA) showed that PA decreased the quantity of H₂ consumed via homoacetogenesis compared to the other LCFAs. The control culture was dominated by Thermoanaerovibrio acidaminovorans (60%), Geobacillus sp. and Eubacterium sp. (28%), while Clostridium sp. was less than 1%. Treatment with PA, MA, MA:PA, or LUA increased the H₂ producers (Clostridium sp. and Bacillus sp.) population by approximately 48, 67, 86, and 86%, respectively.     

In situ-forming injectable hydrogels for regenerative medicine

Regenerative medicine involves interdisciplinary biomimetic approaches for cell therapy and tissue regeneration, employing the triad of cells, signals, and/or scaffolds. Remarkably, the field of therapeutic cells has evolved from the use of embryonic and adult stem cells to the use of induced pluripotent stem cells. For application of these cells in regenerative medicine, cell fate needs to be carefully controlled via external signals, such as the physical properties of an artificial extracellular matrix (ECM) and biologically active molecules in the form of small molecules, peptides, and proteins. It is therefore crucial to develop biomimetic scaffolds, reflecting the nanoenvironment of three-dimensional (3D) ECM in the body. Here, we describe in situ-forming injectable hydrogel systems, prepared using a variety of chemical crosslinkers and/or physical interactions, for application in regenerative medicine. Selective and fast chemical reactions under physiological conditions are prerequisites for in situ formation of injectable hydrogels. These hydrogels are attractive for regenerative medicine because of their ease of administration, facile encapsulation of cells and biomolecules without severe toxic effects, minimally invasive treatment, and possibly enhanced patient compliance. Recently, the Michael addition reaction between thiol and vinyl groups, the click reaction between bis(yne) molecules and multiarm azides, and the Schiff base reaction have been investigated for generation of injectable hydrogels, due to the high selectivity and biocompatibility of these reactions. Noncovalent physical interactions have also been proposed as crosslinking mechanisms for in situ forming injectable hydrogels. Hydrophobic interactions, ionic interactions, stereocomplex formation, complementary pair formation, and host–guest interactions drive the formation of 3D polymeric networks. In particular, supramolecular hydrogels have been developed using the host–guest chemistry of cyclodextrin (CD) and cucurbituril (CB), which allows highly selective, simple, and biocompatible crosslinking. Molecular recognition and complex formation of supramolecules, without the need for additional additives, have been successfully applied to the 3D network formation of polymer chains. Finally, we review the current state of the art of injectable hydrogel systems for application in regenerative medicine, including cell therapy and tissue regeneration.