Effect of iron on the surface, degradation and ion release properties of phosphate-based glass fibres

Phosphate-based glass fibres (PGF) have the unique characteristic of being completely soluble in an aqueous environment, releasing bioactive and biocompatible ions. They have been proposed as tissue engineering scaffolds for craniofacial skeletal muscle regeneration, where myoblasts are seeded directly onto the fibres. Studies have shown that these cells have a preference in their initial attachment to fibres of certain composition and size, which in turn control the rate of degradation. This study investigated the relationship between the surface properties, degradation properties and ion release (cationic and anionic species) by altering the chemical composition of the PGF. Iron oxide (Fe2O3) was incorporated into glasses containing P2O5 (50 mol%), CaO (30 mol%) and Na2O (20 mol%). Six glass compositions with Fe2O3 ranging from 0 to 5 mol% by replacing the equivalent Na2O mol% were investigated. Contact angle measurements showed that polar interactions occurring on the glass surfaces diminished with increasing Fe2O3 content. This behaviour was reflected in the estimated surface energies of the glasses, where the overall surface energy decreased with increasing Fe2O3 content due to the decrease in polar or acid/base component. The incorporation of up to 5 mol% Fe2O3 into PGF resulted in a significant reduction in the degradation rate (by two orders of magnitude), which can be related to the formation of more hydration resistant P-O-Fe bonds. However, the degradation rate increased with decreasing fibre diameter (comparing average diameters of 31.6 +/- 6.5 microm versus 13.1 +/- 1.3 microm) for a given mass of fibre, and this is related to the surface area to volume ratio. Taken together the results suggest that fibres with the larger diameters and containing 3-5 mol% Fe2O3 could initially be a more durable scaffold than ones with 1 or 2 mol% Fe2O3 for initial cell attachment.     

16例染色体异常核型分析

目的与方法本文对189例自然流产、闭经、发育不全患者进行细胞遗传学检查,结果发现异常核型16例,异常核型涉及1、3、4、5、6、7、8、9、10、 15、X、Y染色体.其中平衡易位10例,性染色体异常3例,大Y染色体3例.结论染色体异常是导致流产、闭经、性发育异常的重要遗传因素,应引起临床医师的高度重视.     

采用MDA-MB-231细胞膜进行表皮生长因子受体活性的检测

目的　探讨能否直接利用肿瘤细胞膜进行表皮生长因子受体 (Epidermalgrowthfactorreceptor,EGFR)催化活性检测。方法　首先筛选出EGFR基因表达水平相对较高的细胞株MDA MB 2 31,通过差速离心制备细胞膜 ,采用Westernblotting检测EGFR催化磷酸化的程度。结果　底物被磷酸化 ,加入特异性拮抗剂AG14 78后 ,磷酸化被抑制。结论　利用肿瘤细胞膜检测EGFR活性的设想是成立的 ,并且其方法简便、经济。     

Association of DR4 with pemphigus

HLA typing for the A, B, C, and D locus antigens was performed on 65 patients with pemphigus vulgaris and on 558 controls living in the Los Angeles area. The patients were divided into several categories. These included Jewish and non-Jewish patients, patients with only mucous membrane involvement, only skin or both mucous membrane and skin involvement, and those with a single-episode or recurrent disease. Depending on the highest titer of anti-intercellular cement substance antibody titer, the patients were categorized into those whose titers were 0-80, 160-320, and 640 or greater. A statistically increased incidence of HLA-A25, HLA-B38, and HLA-DR4 antigens was observed in patients compared to controls. This incidence was significantly higher in Jewish compared to non-Jewish patients. The correlations were insignificant in the group with an antibody titer of 0-80, but significant in those with a titer of 160-320, and even more significant in those with titers greater than 640. No significant differences were present between patients who had a single-episode or recurrent disease or in those that had only mouth or only skin involvement. In all categories tested, the association was stronger with DR4 than with A26 or B38. DR4 was present equally in B38-positive and B38-negative patients. The primary association of pemphigus vulgaris may be with the DR4 antigen, and it may be a marker for the severity of the disease.     

Autoantibody level modification in adult patients with idiopathic thrombocytopenic purpura following intravenous immunoglobulin treatment

The aim of this study was to determine whether treatment of patients with immune thrombocytopenic purpura (ITP) with intravenous immunoglobulin (IVIg) is associated with a modification in the antiplatelet glycoprotein (GP) antibodies (Abs). Fourteen patients with ITP (11 females and 3 males, mean age 36.6 years, range 18-72) received one to four IVIg treatment courses. The preparation used was ISIVEN that was given in a dose of 2 g/kg body weight in a 5-day schedule and in monthly intervals. Levels of IgG, IgM and IgA isotypes of Abs to GPs IIb/IIIa and Ib/IX were measured before the treatment, and before and after each treatment course. Two patients did not respond to IVIg, 6 had a temporary response, 5 had a sustained response and 1 patient responded well to the treatment but was lost to follow-up. The patients had a high prevalence of serum Abs directed against GPs IIb/IIIa and Ib/IX before the treatment, and the mean IgG isotype levels of both Abs increased after each treatment course, and decreased again before the following course began. Whenever high Ab levels of either isotype (> 10 U/ml) were detected before the treatment, they were significantly decreased before the last treatment course. The elevated levels of IgG Abs to IIb/IIIa and Ib/IX after every course are probably a result of displacement of these Abs from Fc receptors by the IVIg, rather than of exogenous infusion of these Abs contained within the IVIg, whereas the decrease in high Ab levels after a few treatment courses results from the immunomodulatory effects of IVIg: suppression of Ab formation, and the presence of anti-idiotypes.     

Selection of a mutant S1 gene during reovirus persistent infection of L cells: role in maintenance of the persistent state

LR-7 cells, variant L cells derived from a type 3 reovirus persistently infected (p.i.) carrier culture (R. Ahmed, W. M. Canning, R. S. Kauffman, A. H. Sharpe, J. V. Hallum, and B. N. Fields, Cell 25, 325-332, 1983) were used to define the viral genes critical for maintenance of the persistent state. A cloned viral isolate (L/C virus) derived from the p.i. culture replicated normally in LR-7 cells, while wild-type (wt) viruses of the three reovirus serotypes replicated less efficiently. To identify the viral gene(s) permitting enhanced replication of L/C virus in LR-7 cells, viral reassortants were prepared by mixed infection of L cells with L/C virus and type 1 wt. Study of the one-step growth curves and final yields of large numbers of reassortants in both L cells and LR-7 cells revealed that the presence of the S1 gene from L/C virus was critical for normal viral replication in LR-7 cells. However, this phenotype was suppressed by the simultaneous presence in reassortants of both the M2 and S4 genes from the type 1 wt parent. The critical change in the S1 gene occurred by passage 13 (63 days) after initiation of the carrier culture. Although multiple mutations are present in the viral population from p.i. cultures, certain specific mutations can be identified as critical for maintenance of the persistent state.     

Cardiac glycosides. 7. Sugar stereochemistry and cardiac glycoside activity

Digitoxigenin alpha-L-, beta-L-, alpha-D-, and beta-D-glucosides; alpha-L-, beta-L-, alpha-D-, and beta-D-mannosides; and alpha-L- and beta-L-rhamnosides were stereoselectively synthesized from the corresponding sugar tetrabenzyl trichloroacetimidates. The Na+,K+-ATPase receptor inhibitory activities of these glycosides (as a measure of receptor binding) were compared with those of digitoxigenin, digitoxigenin 6'-hydroxy-beta-D-digitoxoside, digitoxigenin beta-D-galactoside, and digitoxigenin beta-D-digitoxoside. The observed activities reveal that a given sugar substituent may have a role in binding of some glycoside stereoisomers, but not others. With alpha-L- and possibly beta-L-rhamnosides, the 5'-CH3 and 4'-OH appear to have a predominant role in binding to the Na+,K+-ATPase receptor. Addition of a 6'-OH to form the corresponding mannosides dramatically disrupts the effect of both the 5'-CH3 and 4'-OH in prompting receptor binding of the alpha-L isomer. However, with the beta-L isomer, some influence of 4'-OH, 3'-OH, and 2'-OH binding remains. With beta-D-glycosides, binding via the "5'-CH3 site" appears to be of little importance and addition of a 6'-OH diminishes activity only slightly. With these beta-D-glycosides, an equatorial 4'-OH, axial 3'-OH, and equatorial 2'-OH groups appear to contribute to binding.     

Quality of mobility measures among individuals with acquired brain injury: an umbrella review

Quality of Life Research - While several mobility measures exist, there is large variability across measures in how mobility is conceptualized, the source of information and the measurement...     

A predictive and prescriptive analytical framework for scheduling language medical interpreters

Health Care Management Science - Although most hospitals in the United States provide medical services in English, a significant percentage of the U.S. population uses languages other than English....