鼻内镜术后不同填塞止血材料的生物相容性

目的:鼻内窥镜手术后填塞止血材料的选择是鼻内镜外科技术中的重要组成部分。分析几种填塞止血材料的生物学特性及作用的局限性,并与传统的凡士林纱条相比较。方法:应用计算机检索中国期刊全文数据库1999-01/2007-06有关止血材料的理化性能、止血性能及其在鼻内镜手术中应用的相关研究文章,检索词"凡士林纱条,高膨胀止血棉,无痛止血海绵,藻酸钙敷料,明胶海绵,生物相容性,鼻内窥镜"。纳入标准:①凡士林纱条、Merocel高膨胀止血棉、Ivalon无痛止血海绵、Sorbalgon藻酸钙敷料及明胶海绵的在鼻内镜手术后的应用的原著类文章。②不同类型止血材料的性能、生物相容性、安全性评价的研究文章。排除重复研究。符合纳入标准的文献30篇。结果:①Merocel高膨胀止血棉与Ivalon无痛止血海绵均为高分子合成的高膨胀止血材料,质地柔韧,有高度亲水性,吸收液体后迅速膨胀压迫出血区,可塑性强,并且可以作为药物载体,减轻炎症反应。填塞后黏膜损伤、炎症反应等全身反应情况较凡士林纱条轻,其不足之处在于产生的压力强度有限,较剧烈的出血得不到有效控制。②Sorbalgon藻酸钙敷料由柔软的海藻与酸钙纤维制成,有良好的生物相容性、顺应性和很强的亲水性,当其与血液和伤口分泌物中的钠盐接触时,即转化为一种凝胶状物质,起到较好的止血作用。填塞后的疼痛、头痛及鼻腔黏膜水肿反应优于凡士林纱条。由于藻酸钙敷料过于柔软,遇水后液化迅速,缺乏韧性和弹性,因此压迫力度不够。③明胶海绵组织相容性好,对人体无明显毒副作用,无抗原性,不会产生过敏反应,但存在压力不够的缺陷。与凡士林纱条一起使用,可以克服单纯胶原蛋白海绵填塞压力不足的缺点,避免了凡士林纱条与创面的直接接触,减少填塞后出血。结论:不同填塞止血材料各有所长,也各有其局限性,可根据患者的具体情况,结合不同止血材料的生物学特性,选择不同材料实行混合填塞和重点填塞。     

Relationship of deoxycytidine kinase and cytoplasmic 5'-nucleotidase to the chemotherapeutic efficacy of 2-chlorodeoxyadenosine

The agent 2-chlorodeoxyadenosine (2-CdA) has chemotherapeutic activity in hairy cell leukemia (HCL) and in refractory chronic lymphocytic leukemia (CLL). The cytotoxic activity of 2-CdA requires the intracellular accumulation of 2-CdA nucleotides. Deoxycytidine kinase (dCK) and cytoplasmic 5'-nucleotidase (5'-NT) are the principal enzymes that phosphorylate 2-CdA and dephosphorylate 2-CdA 5'-monophosphate, respectively. The net accumulation of 2-CdA nucleotides may therefore depend on both dCK and 5'-NT. The purpose of the present experiments was to determine if there is a relationship between pretreatment levels of dCK and 5'-NT in HCL and in CLL cells, and the clinical outcome of 2- CdA treatment. As measured by a direct immunoassay for dCK in 25 CLL patients, and by a 5'-NT activity assay in 23 patients, mean dCK levels were significantly higher in 2-CdA responders than in nonresponders (P < .01), whereas mean 5'-NT levels were significantly lower in 2-CdA responders than in nonresponders (P < .05). Mean dCK levels were higher in six HCL 2-CdA responders than in one nonresponder, whereas mean 5'- NT levels were lower in the 2-CdA responders than in the nonresponder. These results suggest that both dCK and 5'-NT are determinants of 2-CdA responsiveness.     

T cell unresponsiveness correlates with quantitative TCR levels in a transgenic model

Two lines of transgenic mice were developed which differ intheir level of expression of V_ß11. To determine therole of TCR density in tolerance induction, these mice werebred with I-E expressing mice and were investigated for toleranceinduction. T cells expressing V_ß11 at high densityare deleted by negative selection. T cells expressing <10%of the normal TCR receptor density are not subject to negativeselection and were not activated in vitro. There is a correlationin receptor density in both strains of mice with in vitro activation.These findings support the notion that there is a definablequantitative signal threshold which is critical for toleranceinduction.     

IL-10 promotes survival of microglia without activating Akt.

IL-10 is an anti-inflammatory cytokine that has recently been shown to promote survival of neurons and glia. Here we establish that IL-10 induces phosphorylation of Stat3 on Tyr(705) and serves as a survival factor for N13 microglial cells. Recombinant IL-10 (10 ng/ml) decreases growth factor withdrawal-induced apoptosis by 50%, as assessed by TUNEL. In contrast to IL-10, IGF-I increases enzymatic activity of PI 3-kinase and causes phosphorylation on serine(473) of Akt but does not prevent microglial apoptosis. These data establish that IL-10 activates Stat3 and inhibits the mitochondrial pathway of cell death without activating the Akt cell survival pathway.