Engineering of a complex bone tissue model with endothelialised channels and capillary-like networks.

In engineering of tissue analogues, upscaling to clinically-relevant sized constructs remains a significant challenge. The successful integration of a vascular network throughout the engineered tissue is anticipated to overcome the lack of nutrient and oxygen supply to residing cells. This work aimed at developing a multiscale bone-tissue-specific vascularisation strategy. Engineering pre-vascularised bone leads to biological and fabrication dilemmas. To fabricate channels endowed with an endothelium and suitable for osteogenesis, rather stiff materials are preferable, while capillarisation requires soft matrices. To overcome this challenge, gelatine-methacryloyl hydrogels were tailored by changing the degree of functionalisation to allow for cell spreading within the hydrogel, while still enabling endothelialisation on the hydrogel surface. An additional challenge was the combination of the multiple required cell-types within one biomaterial, sharing the same culture medium. Consequently, a new medium composition was investigated that simultaneously allowed for endothelialisation, capillarisation and osteogenesis. Integrated multipotent mesenchymal stromal cells, which give rise to pericyte-like and osteogenic cells, and endothelial-colony-forming cells (ECFCs) which form capillaries and endothelium, were used. Based on the aforementioned optimisation, a construct of 8 × 8 × 3 mm, with a central channel of 600 µm in diameter, was engineered. In this construct, ECFCs covered the channel with endothelium and osteogenic cells resided in the hydrogel, adjacent to self-assembled capillary-like networks. This study showed the promise of engineering complex tissue constructs by means of human primary cells, paving the way for scaling-up and finally overcoming the challenge of engineering vascularised tissues.

Identification of markers tightly linked to tomato yellow leaf curl disease and root-knot nematode resistance by multiplex PCR.

Seven different commercial F1 hybrids and two F2 populations were evaluated by multiplex PCR to identify plants that are homozygous or heterozygous for Ty-1 and Mi, which confer resistance to tomato yellow leaf curl disease and root-knot nematode, respectively. The Ty-1 and Mi markers were amplified by PCR and identified by digestion of the amplicons with the TaqI enzyme. The hybrids E13 and 288 were found to be Ty/ty heterozygous plants with 398-, 303-, and 95-bp bands, and B08, 314, 198, and A10 were found to be ty/ty homozygous plants with a 398-bp band; whereas 098 did not give any PCR products. The hybrids E13 and 198 were found to be Mi/Mi homozygous plants with 570- and 180-bp bands, and 288 and A10 were found to be Mi/mi heterozygous plants, with 750-, 570- and 180-bp bands, and B08, 109 and 314 were found to be mi/mi homozygous plants with only a 750-bp band. We additionally developed a multiplex PCR technique for JB-1 and Mi, which confer resistance to tomato yellow leaf curl disease and root-knot nematode. The JB-1 marker identified the genotype of the Ty gene, and the plants that produced the 400-bp band were ty/ty homozygous plants, whereas the plants that produced 400- and 500-bp bands were resistant to tomato yellow leaf curl disease. We conclude that multiplex PCRs can be used to reproducibly and efficiently detect these resistance genes.

Increased formation and degradation of malondialdehyde-modified proteins under conditions of peroxidative stress.

The effect of increased in vivo lipid peroxidation on excretion of the main urinary metabolites of malondialdehyde (MDA) was investigated. peroxidative stress in the form of vitamin E deficiency or the administration of iron nitrilotriacetate or carbon tetrachloride was imposed on rats fed an MDA-free diet. Significant increases were observed in excretion of the lysine-MDA adduct epsilon-propenal lysine, its N-acetyl ester, and free MDA. Under the conditions imposed, the increments in excretion of the lysine adducts reflect increased peroxidative modification of tissue proteins in vivo. These adducts also were found to be the main forms of MDA excreted in human urine. Reacting 14C-bovine serum albumin (BSA) with MDA resulted in its accelerated proteolysis in vitro by soluble enzyme preparations derived from human erythrocytes and rat liver mitochondria. The increments observed were similar to those reported for the hydrolysis of BSA following its exposure to hydroxyl radicals. The results show that lipid peroxidation in vivo results in peroxidative damage to tissue proteins and indicate that such proteins are subject to an accelerated rate of proteolysis.

Effects of trinitrotoluene on serum phosphorylase A activities and on calcium contents in men and rats.

Wistar rats were exposed to trinitrotoluene (TNT) for 6 weeks. After initiation of TNT exposure, serum phosphorylase A activities and calcium contents were assayed for every 2 weeks. Both of these 2 parameters increased in rats treated with 50 and 100 mg TNT/kg b.w. at 3 intervals. Serum phosphorylase A activities and calcium contents of TNT exposure worker increased too.

[Effects of exposure to TNT on sex hormones in male workers].

Field investigation on labour hygiene in two plants producing trinitrotoluene (TNT) in Henan Province showed most air TNT levels in the workplace exceeded national maximum allowable concentration (MAC 1 mg/m3) and the skin of the workers exposed to TNT was severely contaminated. Determinations of serum levels of sex hormones showed those of testosterone were lower, but those of interstitial cell-stimulating hormone (ICSH or LH) and follicle stimulating hormone (FSH) were higher in workers exposed to TNT than that in controls with statistical significance (P < 0.01).

Some altered concentrations of elements in semen of workers exposed to trinitrotoluene.

OBJECTIVES: A cross sectional study was performed to find the concentrations of elements contained in the semen of workers exposed to trinitrotoluene (TNT). SUBJECTS AND METHODS: Semen of exposed workers in two TNT plants located in He-Nan Province in 1992 were examined. RESULTS: The average TNT concentrations in the workplace, except the packing site, were found to have exceeded the maximal allowable concentration (MAC, 1 mg/m3); skin contaminations of male workers exposed to TNT were higher after a shift than in controls, and correlated with the total blood concentrations of TNT, 4-amino-2, 6-dinitrotoluene (4A), and 2-amino-4, 6-dinitrotoluene (2A). Cu, Zn, Na, Mg, and Se concentrations were significantly decreased, but K, Ca, Co, Mn and Li contents were not significantly changed in the semen of workers exposed to TNT. Compared with the control group, the percentage of liquifying time of semen, the sperm malformation incidence, and viability in the men exposed to TNT were all significantly changed. CONCLUSIONS: Men exposed to TNT have decreased concentrations of some elements is semen and altered semen physiology.