人脂肪干细胞复合脱细胞软骨基质支架在生物反应器中构建组织工程软骨

目的:观察人脂肪干细胞复合脱细胞软骨基质支架在生物反应器中初步构建组织工程软骨的可行性。方法:实验于2005-04/2006-05在解放军总医院骨科研究所完成。脂肪组织和关节软骨均来自膝关节置换术中切除的组织,并经患者知情同意。关节软骨冻干后经粉碎机粉碎,过筛,选取25～38μm大小的软骨微粒。在样品中先加入2.5g/L胰蛋白酶,37℃消化24h,再加入1%Triton X-100震荡72h。将软骨微粒和蒸馏水按1∶3的比例混合后滴加在模板中,置入冷冻干燥机冻干后行紫外线交联。紫外线照射8h完成。最后经25kGy 60Co辐照灭菌完成支架制备。取膝关节置换术中切除的髌下脂肪垫,酶消法获得脂肪干细胞,扩增后复合于脱细胞软骨基质制成圆柱状三维支架上(细胞密度5×1010L-1),置于生物反应器中进行诱导培养,同时设静态培养组作为对照,3周后观测大体形态和组织学形态变化,同时进行组织化学(包括番红花O,阿利新蓝染色)和Ⅱ型胶原免疫组织化学分析。结果:生物反应器组诱导培养3周苏木精-伊红染色显示支架结构消失,只有中心区域残存少量支架结构;静态培养组支架结构尚存在,有少量基质分泌。番红花O染色显示生物反应器组细胞外有大量蛋白聚糖沉积,阿利新蓝染色表明有软骨特异性蛋白多糖的聚集;而静态培养组只有部分区域染色且淡于生物反应器组。Ⅰ型胶原免疫组化的结果显示,在生物反应器组细胞能够合成大量软骨细胞特异性胶原成分,而静态培养组呈弱阳性。结论:生物反应器培养明显促进了脂肪干细胞的增殖与软骨分化,是体外构建组织工程软骨的良好方法。     

Respiratory infection and otitis media visits in relation to pneumococcal conjugate vaccine use in Saskatchewan

BACKGROUND:

In Saskatchewan, pneumococcal conjugate vaccination (PCV) was offered to high-risk children in 2002 and to all infants in 2005.

OBJECTIVE:

To describe trends in the frequency of medical visits for lower respiratory tract infection (LRI) and otitis media (OM) in relation to PCV use during the period 1990 to 2008.

METHODS:

Statistics regarding the number of children covered by the health insurance plan, PCV administration, and medical visits with a diagnostic code associated with LRI and OM were provided by Saskatchewan Health. Monthly rates were analyzed using dynamic state space models.

RESULTS:

In all series, there was a marked seasonal cycle and some higher-than-expected winter peak values, possibly associated with epidemics of specific respiratory viruses. Three abrupt decreases in baseline rate were observed for LRI and the final one, in February 2007, could be related to the increased proportion of children vaccinated with PCV. There was no statistical correlation between PCV use and OM visit frequency.

CONCLUSION:

Many environmental, biological and administrative factors may influence health services use, and an effect of low magnitude of a particular vaccine pertaining to nonspecific outcomes could be obscured in time-series analyses.     

Stem cell factor retards differentiation of normal human erythroid progenitor cells while stimulating proliferation

Stem cell factor (SCF), the ligand for the c-kit tyrosine kinase receptor, markedly stimulates the accumulation of erythroid progenitor cells in vitro. We now report that SCF delays erythroid differentiation among the progeny of individual erythroid progenitors while greatly increasing the proliferation of these progeny. These effects appear to be independent of an effect on maintenance of cell viability. Highly purified day-6 erythroid colony-forming cells (ECFC), consisting mainly of colony-forming units-erythroid (CFU-E), were generated from human peripheral blood burst-forming units-erythroid (BFU-E). Addition of SCF to the ECFC in serum-free liquid culture, together with erythropoietin (EP) and insulin-like growth factor 1 (IGF-1), resulted in a marked increase in DNA synthesis, associated with a delayed peak in cellular benzidine positivity and a delayed incorporation of 59Fe into hemoglobin compared with cultures without SCF. In the presence of SCF, the number of ECFC was greatly expanded during this culture period, and total production of benzidine-positive cells plus hemoglobin synthesis were ultimately increased. To determine the effect of SCF on individual ECFC, single-cell cultures were performed in both semisolid and liquid media. These cultures demonstrated that SCF, in the presence of EP and IGF-1, acted on single cells and their descendants to delay erythroid differentiation while substantially stimulating cellular proliferation, without an enhancement of viability of the initial cells. This was also evident when the effect of SCF was determined using clones of ECFC derived from single BFU-E. Our experiments demonstrate that SCF acts on individual day-6 ECFC to retard erythroid differentiation while simultaneously providing enhanced proliferation by a process apparently independent of an effect on cell viability or programmed cell death.     

Association of in utero sensitization to Schistosoma haematobium with enhanced cord blood IgE and increased frequencies of CD5- B cells in African newborns

This study investigated in utero priming as a consequence of maternal parasitic infections. Cord blood plasma samples of 63 African newborns were assessed by enzyme-linked immunosorbent assay for their content of total and schistosome-specific or filaria-specific IgE and IgG4. The frequencies of lymphocyte phenotypes in cord blood were also determined by using flow cytometry, and were compared with those of European newborns. We found significantly increased schistosome soluble egg antigen (SEA)-specific IgE in cord plasma of those born to mothers with schistosome infections and correlations between fetal and maternal SEA-specific and filaria antigen-specific IgE. These data are evidence for in utero priming of the fetal immune system to maternal helminth infections. Furthermore, we show significantly enhanced percentages of CD5- B cells in African newborns cord blood compared with Europeans, which is consistent with earlier maturation of the African fetal immune system.     

Needle biopsy of renal allografts: comparison of two techniques

Two techniques for renal allograft biopsy were retrospectively evaluated to compare relative safety and efficacy. After ultrasound (US) localization of the kidney and biopsy with a hand-held 14-gauge cutting needle, an adequate specimen was obtained in 74 of 77 cases (96%). Major complications occurred in six of these 77 cases (8%). One hundred four biopsies were performed by using a smaller 18-gauge cutting needle with a spring-loaded biopsy "gun" and real-time US guidance. With this newer technique, specimens adequate for diagnosis were obtained in 99 biopsies (95%). There was a single major complication with this technique (1%). The 18-gauge needle with real-time US guidance yields comparably adequate specimens with a lower frequency of complications.     

The relationship of dysfunctional attitudes to personality in depressed patients.

AIM: To examine the relationship between dysfunctional attitudes and personality in depressed patients. METHOD: One hundred depressed patients completed both the Dysfunctional Attitudes Scale (DAS) and the Temperament and Character Inventory (TCI). RESULTS: Scores on the DAS correlated with duration of depression, age of onset of depression, age, harm avoidance and self-directedness. In a multiple regression analysis three measures explained 45% of the DAS score. These were duration of depression, reward dependence and self-directedness. In both the univariate analyses and multiple regression the strongest predictor of dysfunctional attitudes was the character dimension of self-directedness. CONCLUSION: The character dimension of self-directedness in the TCI which assesses an individuals' self-concept, relates highly with the dysfunctional attitudes score on the DAS. Given that the TCI assesses personality within a broader framework of a psychobiologic and developmental model, self-directedness may have a wider application as a measure of self-concept than the DAS.