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Purpose: Benzalkonium chloride (BAK) is a common preservative in ophthalmic formulations that causes cytotoxic damage to the corneal epithelial cells. This study aims to explore the role of mesenchymal stem cell (MSC)-derived conditioned medium in modulating the BAK-induced cytotoxic effects in cultured human corneal epithelial cells (HCECs) as a cell-free therapeutic agent. Methods: The in vitro cultured HCECs derived from a HCE cell line were treated with BAK (0.001% and 0.005%, diluted in DMEM/F12, v/v) for 15 min, washed with 1xPBS, and allowed to recover for 24 h in human bone marrow MSC-derived conditioned medium (MSC-CM: undiluted (100%) and diluted (50%, v/v)). On the other hand, HCECs were co-incubated with BAK (0.005%, v/v) and MSC-CM (100% and 50%, v/v) for 24 h. The HCEC-derived conditioned medium (HCE-CM) was used as an optimal control for MSC-CM, whereas HCECs cultured in DMEM/F12 were used as a control. The DMEM/F12 was used as the base medium for the culture of HCECs and preparation of HCE- and MSC-CM. The role of MSC-CM in modulating the metabolic activity, cell death, epithelial repair, and proliferation, in BAK-treated HCECs was evaluated using MTT assay, Propidium iodide staining, scratch assay, and Ki-67 staining, respectively. Results: Compared to the control, recovery of BAK-treated (0.001% and 0.005%, for 15 min) HCECs in MSC-CM showed significantly reduced cell death with enhanced metabolic activity, epithelial repair, and proliferation. However, in comparison with HCE-CM, the beneficial effects of MSC-CM were predominantly observed at lower BAK concentration (0.001%, for 15 min). Whereas the co-incubation of BAK (0.005%) and MSC-CM for a longer duration (24 h) was marginally beneficial. Conclusions: Our results suggest that the MSC-CM is effective in modulating the BAK-induced cell death, retardation of metabolic activity and proliferation in cultured HCECs, particularly at lower concentration (0.001%) and shorter exposure (15 min) of BAK. [ABSTRACT FROM AUTHOR]

Corneal pathologies are a major cause of blindness and visual impairment, especially in the developing world. However, not only is there a global shortage of donor corneal tissue, but a significant proportion of these blinding pathologies also carry an unfavourable long-term prognosis for conventional corneal transplantation. In the last few decades, there has been a spurt of research on developing alternate approaches to address corneal blindness, including stem cell therapy. After the discovery of epithelial stem cells at the limbus, successful cell-based approaches to treat severe ocular surface disease were developed and have subsequently become widely practised across the world. More recently, mesenchymal stem cells were identified near the epithelial stem cells at the limbus, providing a unique opportunity to develop regenerative therapies for both corneal epithelial and stromal pathologies. This review firstly emphasises on qualifying limbal stem cells as either epithelial or mesenchymal and then summarises all the existing knowledge on both cell types and their individual roles in corneal regeneration. The review describes the history, indications, techniques, and outcomes of the different methods of limbal epithelial stem cell transplantation and elaborates on the potential applications of limbal mesenchymal stem cell therapy. [ABSTRACT FROM AUTHOR]

Background & objectives: The PAX5, a paired box transcription factor and B-cell activator protein (BSAP), activates B-cell commitment genes and represses non-B-cell lineage genes. About 14 transcript variants of PAX5 have been observed in human. Any alteration in its expression pattern leads to lymphogenesis or associated diseases and carcinogenesis in non-lymphoid tissues. Its mechanisms of function in pathophysiology of non-Hodgkin's lymphoma (NHL) are unclear. This study was intended to explore influence of PAX5 in cascade of NHL pathogenesis and diagnosis. Methods: Samples of 65 patients were evaluated by immunohistochemical staining for cellular localization of PAX5, CD19, CD3, cABL, p53, Ras and Raf and by TUNEL assay, RNA-isolation and reverse transcriptase (RT)-PCR, Western blot analysis, and lactate dehydrogenase (LDH) specific staining. Results: B-cell type NHL patients were positive for PAX5, p53, Ras, CD19, Raf and CD3. All of them showed TUNEL-positive cells. The differential expression pattern of PAX5, CD19, p53, CD3, ZAP70, HIF1α, Ras, Raf and MAPK (mitogen-activated protein kinase) at the levels of transcripts and proteins was observed. The LDH assay showed modulation of LDH4 and LDH5 isoforms in the lymph nodes of NHL patients. Interpretation & conclusions: The histological observations suggested that the patients represent diverse cases of NHL like mature B-cell type, mature T-cell type and high grade diffuse B-cell type NHL. The findings indicate that patients with NHL may also be analyzed for status of PAX5, CD19 and ZAP70, and their transcriptional and post-translational variants for the differential diagnosis of NHL and therapy [ABSTRACT FROM AUTHOR]

Titania reinforced hydroxyapatite (T-HAP) nanopowders have been receiving great attention in orthopedic and dental implant applications owing to their high bioactivity and good mechanical properties. In the present study, T-HAP nanopowders having 20 wt.% of TiO2 were synthesized by co-precipitation method. With an objective of finding out suitable aging time, T-HAP sols were aged for different time periods, prior to powder synthesis. XRD and FTIR were employed to characterize the phase and molecular structures of nanopowders, respectively. Accurate crystallographic information of nanopowders was thoroughly investigated using Rietveld refinement technique. It was observed that all T-HAP nanopowders were biphasic, composed of HAP and anatase TiO2 phases, notwithstanding the influence of aging time. On the other hand, crystal structural properties such as wt.% of phases, lattice parameters, crystal size, crystallinity and Ca/P molar ratio varied with the increase in aging time. FTIR suggested the formation of carbonated apatitic structure in all T-HAP nanopowders. Critical analysis of structural properties suggested the optimal aging time period of 16 hours to produce T-HAP nanopowders having suitable crystallographic structure. [ABSTRACT FROM AUTHOR]

Fishes are an attractive animal model for investigation of the embryonal and postembryonal central nervous system development and participation in this processes some neurochemical agents. Pacific salmons Oncorhynchus masou, sturgeons Acipencer schrenckii and carps Cyprinus carpio were the objects of our investigation. The purpose of our investigation is to explore the participation of some neurotransmitters (dopamine, GABA), gasotransmitters (NO and H2S) and transcription factor Pax6 in the processes of post-embryonic neurogenesis in fish. In this work, we used methods of immunohistochemical labeling tyrosine hydroxylase, GABA, neuronal NOS, cystathionine β-synthase, transcription factor Pax6, PCNA. The area, which contained apoptosis have been diagnosed by TUNEL-labeling. Results of our research were established, that population of undifferentiated cells, which producing a OH, NOS, Pax6 on the territory of the matrix areas, containing proliferative PCNA-ir cells in the young O. masou 3-, 6-months and 1year old was founded. The expression of Pax6 in the zones of proliferation, differentiation and migration in the brain integrative centers of adult carp and colocalization of Pax6, TH and CBS in the matrix zone of the brainstem, cerebellum and of lobus vagi. We argue that in periventricular proliferative zones identified expression tyrosine hydroxylase, GABA, NO and H2S, participating in the regulation of the basic histogenetic processes as morphogenetic factors, carrying out paracrinic and autocrinic regulation of cells-predecessors proliferation, migration of differentiating neurons and the expression of specific genes and synthesis. [ABSTRACT FROM AUTHOR]