Library

Notes: Summary.  To investigate the molecular defects in two Chinese pedigrees with inherited factor V (FV) deficiency.A 37-year-old male (proband 1) and an 18-month-old boy (proband 2) were diagnosed as inherited coagulation FV deficiency by severely reduced plasma levels of FV activity and antigen. All 25 exons and their flanking sequence of F5 gene were amplified by polymerase chain reaction (PCR) for both probands and the PCR products were directly sequenced. Total RNA was extracted from the peripheral lymphocytes of proband 1 for detecting the changes at mRNA level.The homozygous deletion IVS8 −2A〉G was identified in the F5 gene of proband 1 and complementary DNA (cDNA) analysis revealed the abolishment of the canonical splicing site by the mutation and the activation of the cryptic acceptor site 24 bp upstream instead. The insertion introduced eight additional amino acids (AA) into the FV protein. Two heterozygous mutations of F5 gene were discovered in proband 2. The 2238-9del AG in exon 13 introduced a premature termination code at 689 AA and the substitution of G6410 by T in exon 23 lead to the missense mutation Gly2079Val.Three F5 gene mutations, IVS8 −2A〉G, 2238-9del AG and G6410T, have been identified in two Chinese pedigree with congenital FV deficiency, respectively.

Notes: Objective and background:  Guided bone regeneration (GBR) has proved to be a suitable and somehow predictable technique for promoting bone regeneration. Avariety of synthetic and naturally derived GBR barriers have been used in clinics to facilitate bone regeneration. These barriers may differ in composition and structure and these may affect the outcomes of GBR. Therefore, the present study was undertaken to evaluate the in vitro ability of osteoblasts (MC3T3-E1) to attach to various GBR membranes.Materials and methods:  Six GBR/GTR (guided tissue regeneration) membranes [BioMend® (BM), Resolut® (RL), Guidor® (GD), EpiGuide® (EG), Gore-Tex® (GT) and Millipore filter® (MP)] were tested. For controls, cells were directly plated on culture dishes (CD). Each test membrane was secured to the bottom of a culture dish with a double-sided adhesive tape. All samples were triplicate. At 1.5 and 24 h after plating of 2 ml (5 × 104 cells/ml) of MC3T3-E1 (passage 7) cells, the specimens were rinsed with phosphate-buffered saline to wash out any unattached cells and then fixed with a 10% buffered formalin solution for 1 d. After washing with distilled water, the cells were stained with hematoxylin. The number of attached cells was counted under a light microscope equipped with an ocular-micrometer in a unit area of 0.25 mm2 (five areas on each membrane). In addition, cell morphology attached to the membranes was evaluated under scanning electron microscope.Results:  Data were presented as mean ± standard error and analyzed for statistical difference using a generalized Wilcoxon's test. Cell attachment at 1.5 h was as follows: MP (27.5 ± 2.1) 〉 RL (17.0 ± 1.4) ≈ BM (14.5 ± 1.4) ≈ EG (11.4 ± 1.0) 〉 GD (5.2 ± 0.8) ≈ GT (3.1 ± 0.6); and at 24 h was: MP (67.6 ± 3.6) 〉 RL (35.8 ± 1.8) 〉 BM (15.4 ± 0.9) ≈ EG (13.3 ± 1.3) 〉 GD (5.9 ± 0.7) ≈ GT (5.6 ± 1.3). At 24 h, the scanning electron microscope finding revealed that cells attached on MP, RL, BM and EG were flatter in shape, like cells on CD, than cells on GD and GT, where cells were rather round.Conclusions:  Results from this study suggested that MP, BM, RL and EG enhanced the early osteoblast attachment. However, the true benefit of this observation in clinic remains to be determined.

Notes: Abstract Si3N4 Ceramic Composites with TiC powder have been fabricated by gas-pressure sintering and their electrical conductivity has been investigated. The ceramic composites with different electrical resistivity consist of Si3N4 powder as an insulating matrix, and TiC as electrically conductive additive. Under tensile loading or compressive unloading, the ΔR/R of TiC/Si3N4 composites reversibly increased. Under compressive loading, the ΔR/R decreased gradually with the increasing of loading up to fracture. The results suggest the possibility of self-monitoring fractures and strains in the composites under tensile and compressive loading.