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Bone tissue engineering studies have brought three‐dimensional scaffolds into focus that can provide tissue regeneration with designed porosity and strengthened structure. Current research has concentrated on the fabrication of natural and synthetic polymer‐based complex structures that closely mimic biological tissues due to their superior biocompatibility and biodegradabilities. Gelatine/Sodium Alginate hydrogels reinforced with different concentrations of β‐Tricalcium Phosphate (TCP) (10, 13, and 15 wt.%) were studied to form 3D bone tissue. Physical, mechanical, chemical, morphological properties and biodegradability of the constructs were investigated. Furthermore, in vitro biological assay with human osteosarcoma cell line (SAOS‐2) was performed to determine the biocompatibility of the constructs. It is found that cell viability rates for all constructs were increased and maximum cell viability rate was attained for 20%Gelatine/2%Alginate/10%TCP (wt.). The present work demonstrates that 3D printed Gelatine/Alginate/TCP constructs with porous structures are potential candidates for bone tissue engineering applications.

Diabetes causes oxidative stress, which in turn generates excessive free radicals resulting in cellular damage. Vitamin C is an antioxidant that protects tissues and organs from oxidative stress. The thymus is one of the most important lymphoid organs, which regulates T-lymphocyte proliferation and maturation. The aim of this study is to investigate the protective effects of vitamin C on the thymus of streptozotocin (STZ)-induced diabetic rats. The mitotic activity and cell integrity of thymic lymphocytes were explored. Wistar Albino rats were divided into three groups: control (Group 1), STZ-diabetes (Group 2) and vitamin C-treated STZ-diabetics (Group 3). Rats received a single intraperitoneal injection of 45 mg/kg STZ to induce diabetes. Vitamin C (20 mg/kg) was administered intragastrically. Semithin and ultrathin sections were examined under a light or an electron microscope, respectively. Considerable numbers of mitotic lymphocytes were observed in the thymus of control rats. In the diabetic rats, however, numbers of mitotic lymphocytes decreased to ∼57% of controls, and cell division abnormalities were observed. Additionally, diabetic rats showed degeneration in the structure of the thymus including trabecular thickening, accumulation of lipid vacuoles, heterochromatic nuclei and loss of mitochondrial cristae. Degradation of medullar and cortical integrity was also detected. In the vitamin C-treated STZ-diabetic group, the structure of the thymus and mitotic activity of the lymphocytes were similar to the control group. These results suggest that vitamin C protects the thymus against injury caused by diabetes and restores thymocyte mitotic activity.

Carbon tetrachloride (CCl4) is widely used to induce liver toxicity in in vitro/in vivo models. Lipid peroxidation (LPO) begins with toxicity and affects cell viability. Recently, the beneficial effects of melatonin and Vitamin D on cell proliferation in human normal and cancer cells were found. This study was planned to evaluate antioxidant and cytoprotective activity of melatonin and Vitamin D in CCl4 induced cytotoxicity in HepG2 and Hep3B hepatoma cell lines. Based on the cytotoxicity assay, melatonin and Vitamin D were evaluated for cytotoprotective potential against CCl4 induced toxicity in HepG2 and Hep3B liver cell lines by monitoring cell viability, LPO and glutathione (GSH) level. Different dosages of CCl4 (0.1, 0.2, 0.3 and 0.4 % v/v) were applied to HepG2 and Hep3B cells in order to determine the most toxic dosage of it in a time dependent manner. The same experiments were repeated with exogenously applied melatonin (MEL) and Vitamin D to groups treated with/without CCL4. Cell viability was determined with MTT measurements at the 2nd, 24th and 48th h. GSH content and Malondialdehyde levels were measured from the cell lysates. As a result, both melatonin and Vitamin D administration during CCl4 exposure protected liver cells from CCl4 induced cell damage. Increase in LPO and decrease in GSH were found in the CCl4 groups of both cells. Contrary to these results administration of MEL and Vitamin D on cells exhibited results similar to the control groups. Therefore, melatonin and Vitamin D might be a promising therapeutic agent in several toxic hepatic diseases.

We investigated the protective effect of vitamin D against liver damage caused by carbon tetrachloride (CCl). Twenty-four male rats were divided into four equal groups: G1, untreated controls; G2, administered CCl; G3, administered both CCl and vitamin D for 10 weeks; G4, administered CCl for 10 weeks and vitamin D for 12 weeks. At the end of experiment, intracardiac blood samples were taken and liver samples were removed. Hepatic damage due to CCl was assessed using biochemistry and histopathology. Glutathione (GSH) levels decreased, while malondialdehyde (MDA) levels increased in liver tissues of G2. Alanine transaminase (ALT), alkaline phosphatase (ALP), and gamma-glutamyl-transaminase (GGT) levels increased, while albumin (ALB) levels decreased. Hepatocyte degeneration, lobular disorder, sinusoid dilation, focal necrotic areas, hyperemia, and glycogen loss were observed. Hepatic fibrosis was observed around portal areas and central veins. Bridging fibrous septa were formed between portal veins. By immunohistochemistry, both matrix metalloproteinase-9 (MMP-9) and desmin reactivity were increased. All aspects of liver damage were at least partially prevented in rats treated with vitamin D. Vitamin D appears to act as an antioxidant and anti-fibrotic to protect the rat liver against damage.

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ÖZET Amaç: Kök hücre (KH) nakli malin kan hastalıkları, kemik iliği yetmezlikleri ve doğumsal kan hastalıklarının tedavisinde kullanılan yöntemdir. Bu amaçla, periferik kan projenitör hücreleri (PKPH) oldukça fazla kullanılmaktadır. Son yıllarda insan embriyonik kök hücrelerinin sahip olduğu pluripotent özelliği bulunan yeni KH türü tanımlanmıştır. Çok küçük embriyonik benzeri (VSEL) kök hücreler olarak adlandırılan bu hücrelerin, yetişkin bireyde periferik kanda (PK) bulunduğu düşünülmektedir. Bu çalışmada VSEL kök hücrelerinin periferik kan kaynağı kullanarak elde edilmesi ve tanımlanması amaçlanmıştır. Gereç ve Yöntem: Donörlerden alınan materyallerden lizis ve fikol gradient yöntemleri kullanılarak elde edilen mononükleer ve eritrosit katmanınlarından, VSEL hücreleri izole edilmiştir. Flov sitometri ve immünfloresan boyama ile NANOG, OCT4, SSEA-4 ve CXCR-4 embriyonal kök hücre belirteçlerinin varlığı incelenmiştir. Western blot yöntemiyle ise, NANOG ve OCT4 proteinlerinin varlığı araştırılmıştır. Bulgular: Flov sitometri sonuçlarına göre debris katmanında, VSEL belirteci taşıyan hücre sayısı CD45-popülasyonuna göre daha yüksek bulunmuştur. Elde edilen western ve immünfloresan sonuçlarına göre yüksek miktarda OCT4 ve NANOG ekspresyonu görülmüştür. Aynı zamanda bu proteinlerin hücre içinde hem sitoplazmada hem de çekirdekte bulunduğu gösterilmiştir. Sonuç: Pluripotent kök hücre belirteci olarak bilinen bu proteinlerin yetişkin periferik kanında yüksek miktarda ekspresyonunun, farklılaşmış dokularda nasıl görev yaptığı sorusunu akıllara getirmektedir. Bu bulgular; periferik kanda pluripotent belirteçler taşıyan yeni bir kök hücre populasyonu bulunduğu tezini güçlendirmekte ve bu konuda yapılacak ileriye dönük klinik çalışmalar içinde temel oluşturmaktadır. Anahtar Kelimeler: Çok küçük embriyonik benzeri (VSEL) kök hücreler, Periferik kan, Pluripotent kök hücre markırları ABSTRACT Objective: Stem cell transplantation is considered to be one of the available treatments for malign or hereditary blood diseases and bone marrow failure. Peripheral blood progenitor cells (PBPC) are widely used for this technique. Recently a new type of stem cell with a pluripotent potential has been identified. These cells, called very small embryonic-like (VSEL) stem cells, are thought to be found in peripheral blood (PB) in adult individuals. The aim of this study was to obtain and identify VSEL stem cells using a peripheral blood source. Material and Method: VSEL cells were isolated from mononuclear and erythrocyte layers obtained by using lysis and ficoll gradient methods from the materials taken from donors. The presence of NANOG, OCT4, SSEA-4 and CXCR-4 embryonal stem cell markers by flow cytometry and immunofluorescence staining was investigated. The presence of NANOG and OCT4 proteins was investigated using the Western blot method. Results: According to the flow cytometry results, the number of cells carrying the VSEL marker was higher in the debris layer than in the CD45-population. Western and immunofluorescence results showe...