Incorporating platelet-rich plasma into electrospun scaffolds for tissue engineering applications

Platelet-rich plasma (PRP) therapy has seen a recent spike in clinical interest due to the potential that the highly concentrated platelet solutions hold for stimulating tissue repair and regeneration. The aim of this study was to incorporate PRP into a number of electrospun materials to determine how growth factors are eluted from the structures, and what effect the presence of these factors has on enhancing electrospun scaffold bioactivity. PRP underwent a freeze-thaw-freeze process to lyse platelets, followed by lyophilization to create a powdered preparation rich in growth factors (PRGF), which was subsequently added to the electrospinning process. Release of protein from scaffolds over time was quantified, along with the quantification of human macrophage and adipose-derived stem cell (ADSC) chemotaxis and proliferation. Protein assays demonstrated a sustained release of protein from PRGF-containing scaffolds at up to 35 days in culture. Scaffold bioactivity was enhanced as ADSCs demonstrated increased proliferation in the presence of PRGF, whereas macrophages demonstrated increased chemotaxis to PRGF. In conclusion, the work performed in this study demonstrated that the incorporation of PRGF into electrospun structures has a significant positive influence on the bioactivity of the scaffolds, and may prove beneficial in a number of tissue engineering applications.     

A study of the effect of nasal modes of ventilation on the incidence of gastro-oesophageal reflux in preterm neonates

Background

Nasal modes of respiratory support cause variable amounts of gastric dilatation which may increase gastro-oesophageal reflux (GER) in preterms. To compare the incidence of GER in nasally ventilated, preterm babies with controls (babies not on ventilation). Type of study: A prospective, observational comparative study.

Method

Twenty-three preterm babies of gestational age 28–36 weeks and weight ranging between 1,000 g and < 2,500 g on either nasal continuous positive airway pressure (nCPAP) or nasal intermittent positive pressure venti-lation (nIPPV) were assessed for GER. They were compared with controls not on ventilation some of who were test babies when off ventilation (subgroup A) and some were unrelated babies not on ventilator but matched for gestational age and weight with test babies (subgroup B). All babies were subjected to continuous, oesophageal pH monitoring with dual sensor (upper and lower oesophageal) catheters. Reflux index (RI) was calculated as the percentage of study time the lower oesophageal pH was < 4. Primary outcome was the RI in the test and controls groups. Secondary outcome was the temporal relation of the reflux with symptoms if any. Numerical data were shown as mean with standard deviation and statistical comparisons were done using the χ²-test, Fischer test, and t-test wherever applicable.

Results

The RI was higher in ventilated babies as compared to the control group, particularly in the subgroup A, where test babies formed their own controls. Grade IV reflux (7 cases) was seen only in the ventilated babies. There was no difference in the incidence of GER in babies on nCPAP as compared with nIPPV. Grade IV reflux could not be reliably predicted by RI alone. No definite temporal relation between episodes of reflux and symptoms could be determined in this study.

Conclusion

There is an increase in GER in preterms on nasal modes of ventilation. A combination of upper (pharyngeal) and lower oesophageal sensors are preferred to a single lower oesophageal sensor when assessing GER by oesophageal pHmetry in neonates.     

Management of ��floating elbow�� in children

Background:

Supracondylar fractures associated with ipsilateral forearm fractures, aptly termed as “floating elbow” is a rare injury in children after a fall from height. The various authors have reported their results with conservative treatment of one or both injuries to aggressive emergency operative fixation of both components.

Materials and Methods:

During a period of three years, the author managed four cases of floating elbow in children. All cases were managed by closed reduction and pinning of both components of the injury.

Results:

All patients recovered full elbow range of motion at three months followup and were rated as excellent as per modified Flynn''s criteria. None of the patients developed cubitus varus deformity, complications related to the pins or delayed union.

Conclusions:

Early closed reduction and K wire fixation of both components of this injury gives better stability and prevents development of complications like compartment syndrome and elbow deformities.     

74例血友病B患者FⅨ基因突变研究

目的 研究导致中国人血友病B的凝血因子Ⅸ（FⅨ）基因突变类型的分布,并比较与美国白种人群有何异同。方法 从患者外周血白细胞抽提基因组DNA,分9段扩增Ⅸ基因外显子序列,用基因扩增转录测序技术直接测序法检出突变。结果 74例患者中有69例查到了FⅨ基因58种突变。分析比较这69例患者FⅨ基因突变类型的分布特征与美国白种人无显著性。中国不同地区之间差异也无显著性。结论 中国人血友病B的FⅨ基因突变类型非常分散,呈高度异质性。与美国白种人之间相比差异无显著性。     

Identification of mutations in the connexin 26 gene that cause autosomal recessive nonsyndromic hearing loss

Mutations in the Cx26 gene have been shown to cause autosomal recessive nonsyndromic hearing loss (ARNSHL) at the DFNB1 locus on chromosome 13q12. Using direct sequencing, we screened the Cx26 coding region of affected and nonaffected members from seven ARNSHL families either linked to the DFNB1 locus or in which the ARNSHL phenotype cosegregated with markers from chromosome 13q12. Cx26 mutations were found in six of the seven families and included two previously described mutations (W24X and W77X) and two novel Cx26 mutations: a single base pair deletion of nucleotide 35 resulting in a frameshift and a C-to-T substitution at nucleotide 370 resulting in a premature stop codon (Q124X). We have developed and optimized allele-specific PCR primers for each of the four mutations to rapidly determine carrier and noncarrier status within families. We also have developed a single stranded conformational polymorphism (SSCP) assay which covers the entire Cx26 coding region. This assay can be used to screen individuals with nonsyndromic hearing loss for mutations in the CX26 gene. Hum Mutat 11:387–394, 1998. © 1998 Wiley-Liss, Inc.     

天然抗氧化剂抗血管生成作用的研究进展

血管生成（Angiogenesis）是指从已有的血管上长出新的毛细血管的过程．在这一过程中,活性氧作为信号分子起着非常重要的作用．因此从天然抗氧化剂中寻找新的血管生成抑制剂已成为近年来研究的热点,我们综述了近年来抗氧化剂的抗血管生成作用、机制以及应用前景的国内外最新研究进展．     

反转录病毒载体介导RNA干扰抑制EphA2在Hela细胞中的蛋白表达

目的：课题前期发现EphA2和配体EphrinAl在宫颈鳞癌细胞和肿瘤相关血管内皮细胞均呈高表达，为基因治疗宫颈癌提供了理想的靶向。以此为基础，利用反转录病毒载体介导的RNA干扰抑制EphA2在Hela宫颈癌细胞中的蛋白表达。方法：实验于2006—01／06在河南省肿瘤病理重点实验室完成。①实验材料：PA317细胞、Hela229细胞购自上海生化细胞所，小鼠NIH3T3细胞为本室保存。EphA2兔抗人多克隆抗体，Actin兔抗人多克隆抗体（美国SantaCruz公司）。②实验方法：从EphA2的mRNA全序列中筛选出1个19nt的靶序列，设计双链发夹结构。以siRNA互补双链寡核苷酸，构建反转录病毒表达载体pSIREN—EphA2，提取质粒，用BglⅡ和EcoRⅠ双酶切进行鉴定。选择经酶切鉴定的正确克隆测序。挑选pSIREN．EphA2抗性克隆细胞扩增，检测转染后Hela细胞中EphA2蛋白的表达水平。结果：@pSIREN-EphA2重组质粒的酶切鉴定：双酶切后形成328bp和6182bp两条电泳条带。②pSIREN-EphA2重组质粒测序：结果与已知序列完全一致。（DEphA2蛋白的表达：经Westernblot分析，重组pSIREN—EphA2转染的Hela细胞中EphA2蛋白表达水平明显降低。结论：通过反转录病毒载体介导的RNA干扰，能够抑制EphA2在Hela细胞中的蛋白表达，为以EphA2为靶点的宫颈癌基因治疗提供新的思路和手段。