Development of a Two-Layer Porous Scaffold Based on Porcine Nasal Septal Cartilage for Orthopedics.

The aim of the study was to design a construct based on a nasal septal cartilage plate providing required cell differentiation in different layers to replace a deep osteochondral defect and develop an algorithm of chemical and physical effect sequence to create non-immunogenic two-layer porous structure with requisite elasto-mechanical properties. MATERIALS AND METHODS: The plates derived from porcine nasal septal hyaline cartilage covered by perichondrium were multi-stage treated including freezing, equilibrating in a hypotonic saline solution (type I specimens); trypsinization, point IR-laser effect, re-trypsinization (type II specimens); a stabilizing effect of crosslinking agents - glyceraldehyde/ribose in an acidic medium - washing (type III specimens).For all type specimens:there were established stability parameters (collagen denaturation temperature using a thermal analysis; and Young's modulus using a mechanical analysis);there were determined morphological characteristics using light and polarization microscopy with classical staining and nonlinear optical microscopy in second-harmonic generation mode. RESULTS: Thermal, mechanical, and morphological properties in type I specimens slightly differed from those of the initial nasoseptal system. A considerable part of cells had destroyed membranes.In type II specimens, thermal stability of collagen frame was significantly lower; Young's modulus decreased more than fourfold compared to type I specimens. Collagen structure of hyaline cartilage appeared to be disarranged, although the morphological differences of the hyaline part and perichondrium preserved. The construct matrix was almost completely decellularized. Successive exposure to laser radiation and trypsin resulted in the formation of partial holes in the matrix, ~100 µm in diameter.In type III specimens, both the thermal stability of the collagen frame and Young's modulus (E) increased. Glyceraldehyde was more effective than ribose, E having reached the value typical for intact hyaline cartilage. Collagen fibers in type III specimens were thicker than in type I and II specimens. The morphological differences of the hyaline part and perichondrium and partial holes were preserved. CONCLUSION: Due to sequential treatment by salts, trypsin, IR-laser radiation, and nontoxic crosslinking agents, nasal septal cartilage plate forms porous acellular construction consisting of two layers formed by type I (from perichondrium) and type II (from hyaline part) collagen fibers. In the present construction, stability, mechanical properties, and size of the partial holes can be assigned for cell colonization. It enables to use the construction to replace articular cartilage defects.

Base-mediated transformation of the agostic (π-allyl)-closo-rhodacarboranes into complexes with an open (1-5-η5)-pentadienyl ligand.

The reactions of agostic (CH3···Rh) complexes [3-{(1-3-η(3))-1,1,2-trimethylallyl}-1-R-2-R'-closo-3,1,2-RhC2B9H9] [1: R = R' = Me; 2: R,R' = µ-(ortho-xylylene); 3: R = Ph, R' = Me] in a cooled (+5 °C) toluene solution with the strong non-nucleophilic base N,N,N',N'-tetramethylnaphthalene-1,8-diamine (tmnd) formally involve a linear coupling of the π-allyl ligand of one molecule of the complex to the π-allyl ligand of the second molecule of the complex, ultimately forming the structurally novel mononuclear species [3-{(1-5-η(5))-2,3-dimethyl-5-(3-methylbuten-2-yl)pentadienyl}-1-R-2-R'-closo-3,1,2-RhC2B9H9] (4, 5) and (6a,b, a mixture of diastereomers). Complexes 5 and 6a,b were also prepared using weaker bases such as PPh3 or even EtOH instead of tmnd. All new complexes 4-6 were characterized by a combination of analytical and multinuclear NMR data, as well as by single-crystal X-ray diffraction studies of two selected species 5 and the major diastereomer of 6, which revealed an open η(5)-pentadienyl coordination mode of the hydrocarbon ligands in these complexes.

[Inhibition of oxidation of human blood low density lipoproteins by carotenoids from paprika]. / Ingibirovanie okisleniia lipoproteinov nizkoi plotnosti plazmy krovi cheloveka karotinoidami papriki.

beta-Carotene (C1), acyl derivatives of capsanthin (C2), and acyl derivatives of capsorubin (C3) were isolated from red paprika (Capsicum annuum) oleoresin. Incorporation of carotenoids C1, C2, and C3 into human plasma LDLs changed the LDL flotation coefficient distribution for LDL fraction 1.019 < d < 1.050 g/ml. The comparative studies of Cu(2+)-catalyzed oxidation for LDL, LDL-C1, LDL-C2, and LDL-C3 revealed that carotenoids C1, C2, and C3 efficiently suppressed the oxidation of LDL, inhibited the formation of conjugated dienes from polyunsaturated fatty acid residues, lowered the content of small dense LDL subfraction, and inhibited the transformation of cholesterol to auto oxidized products (in particular to 5,6-epoxycholesterol, 7-ketocholesterol and 7 beta-hydroxycholesterol). This suggests that the main carotenoids may effectively inhibit LDL oxidation in vitro with probable lowering the "atherogenic" LDL subfraction production in vivo.