Assessment of naturally occurring covalent and total dimer levels in human IgG1 and IgG2

Antibody dimers, two self-associated monomers, have been detected on both recombinantly expressed and endogenous human IgG proteins. Nearly 10 years ago, Yoo et al. (2003) described low levels of IgG2 covalent dimer, in human serum, but did not quantify the levels. Here we quantify the total and covalent dimer levels of IgG2 and IgG1 in human blood, and study the origin of covalent dimer formation. Low levels (<1%) of total IgG1 and IgG2 dimers were measured in freshly prepared human plasma. Both IgG1 and IgG2 covalent dimers were also found in plasma. Whereas IgG1 covalent dimer levels were significantly reduced by steps intended to eliminate artifacts during sample preparation, IgG2 covalent dimer levels remain stable in such conditions. About 0.4% of IgG2 in plasma was in a covalent dimer form, yet very little (<0.03%) of IgG1 covalent dimer could be considered naturally occurring. IgG2 dimer also formed in vitro under conditions designed to mimic those in blood, suggesting that formation occurs in vivo during circulation. Thus, small amounts of covalent IgG2 dimer do appear to form naturally.     

In vitro and in vivo evaluation of porous PCL-PLLA 3D polymer scaffolds fabricated via salt leaching method for bone tissue engineering applications

Three dimensional porous scaffolds composed of various ratios of polycaprolactone and poly(L-lactic acid) (PLLA) were prepared using salt leaching method for bone regeneration applications. Surfaces of the scaffolds were visualized using scanning electron microscope (SEM) and the combination of the polymers was confirmed by FT-IR. Addition of PLLA increased the porosity and pore sizes of the scaffolds and also the scaffolds’ compressive strength initially. Osteoblast-like cells were used and it was found that the samples’ cell biocompatibility was further promoted with the increase in PLLA content as observed via cell proliferation assays using MTT, gene expression with RT-PCR, and micrographs from SEM and confocal microscopy. Samples were then implanted into male rabbits for 2 months, and histological staining and micro-CT histomorphometry show that new bone formations were detected in the site containing the implants of the scaffolds and that bone regeneration was further promoted with the increased concentration of PLLA in the scaffold.     

Periarticular Injection with Corticosteroid Has an Additional Pain Management Effect in Total Knee Arthroplasty

Purpose

Although the analgesic effects of corticosteroids have been well documented, little information is available on periarticular injection (PI) containing corticosteroids for early postoperative pain management after total knee arthroplasty (TKA). We performed a prospective double-blind randomized trial to evaluate the efficacy and safety of an intraoperative corticosteroid PI in patients undergoing TKA.

Materials and Methods

Seventy-six consecutive female patients undergoing bilateral staged TKA were randomized to receive steroid or non-steroid PI, with 3 months separating the procedures. The steroid group received PI with a mixture containing triamcinolone acetonide (40 mg). The non-steroid group received the same injection mixture without corticosteroid. During the postoperative period, nighttime pain, functional recovery [straight leg raising (SLR) ability and maximal flexion], patient satisfaction, and complications were recorded. Short-term postoperative clinical scores and patient satisfaction were evaluated at 6 months.

Results

The pain level was significantly lower in the PI steroid than the non-steroid group on the night of the operation (VAS, 1.2 vs. 2.3; p=0.021). Rebound pain was observed in both groups at POD1 (VAS, 3.2 vs. 3.8; p=0.248), but pain remained at a low level thereafter. No significant differences were seen in maximal flexion, frequency of acute rescuer, clinical scores, and patient satisfaction. The steroid group was able to perform SLR earlier than the non-steroid group (p=0.013). The incidence of complications was similar between the groups.

Conclusion

PI containing a corticosteroid provided an additional pain-relieving effect on the night of the operation. In addition, corticosteroid PI did not increase the perioperative complications of TKA.     

Poly(lactic acid-co-glycolic acid)–poly(ethylene glycol)–poly(lactic acid-co-glycolic acid) thermogel as a novel submucosal cushion for endoscopic submucosal dissection

Endoscopic submucosal dissection (ESD) is a clinical therapy for early stage neoplastic lesions in the gastrointestinal tract. It is, however, faced with a crucial problem: the high occurrence of perforation. The formation of a submucosal fluid cushion (SFC) via a fluid injection is the best way to avoid perforation, and thus an appropriate biomaterial is vital for this minimally invasive endoscopic technique. In this study, we introduced an injectable thermogel as a novel submucosal injection substance in ESD. The hydrogel synthesized by us was composed of poly(lactic acid-co-glycolic acid)–poly(ethylene glycol)–poly(lactic acid-co-glycolic acid) (PLGA–PEG–PLGA) triblock copolymers. The polymer/water system was a low-viscosity fluid at room temperature and thus easily injected, and turned into a non-flowing gel at body temperature after injection. The submucosal injection of the thermogel to create SFCs was performed in both resected porcine stomachs and living minipigs. High mucosal elevation with a clear margin was maintained for a long duration. Accurate en bloc resection was achieved with the assistance of the thermogel. The mean procedure time was strikingly reduced. Meanwhile, no obvious bleeding, perforation and tissue damage were observed. The application of the thermogel not only facilitated the ESD procedure, but also increased the efficacy and safety of ESD. Therefore, the PLGA–PEG–PLGA thermogel provides an excellent submucosal injection system, and has great potential to improve the ESD technique significantly.     

Biosynthesis of collagen I,II, RUNX2 and lubricin at different time points of chondrogenic differentiation in a 3D in vitro model of human mesenchymal stem cells derived from adipose tissue

The first aim of the study was to identify the most appropriate time for differentiation of adipose tissue derived mesenchymal stem cells (MSCs) to chondrocytes, through the self-assembly process. For this purpose, the expression of some chondrocyte markers, such as collagen type I, collagen type II, RUNX2 and lubricin was investigated at different times (7, 14, 21 and 28 days) of chondrogenic differentiation of MSCs, by using immunohistochemistry and Western blot analysis. The second aim of the study was to demonstrate that the expression of lubricin, such as the expression of collagen type II, could be a possible biomarker for the detection of chondrocytes well-being and viability in the natural self-assembling constructs, called ‘cell pellets’. Histology (hematoxylin and eosin) and histochemistry (alcian blue staining) methods were used to assess the chondrogenic differentiation of MSCs. The results showed that after 21 days the differentiated chondrocytes, when compared with MSCs cultured without chondrogenic medium (CD44, CD90 and CD105 positive; CD45, CD14 and CD34 negative), were able to produce significant quantities of collagen type I, collagen type II, and lubricin, suggesting hyaline cartilage formation. During the differentiation phase, the cells showed a reduced expression of RUNX2, a protein expressed by osteoblasts. Our studies demonstrated that 21 days is the optimum time for the implantation of chondrocytes differentiated from adipose tissue-derived MSCs. This information could be useful for the future development of cell-based repair therapies for degenerative diseases of articular cartilage.     

丹红注射液延迟缺氧性呼吸抑制的发生及其机制

 目的：探讨丹红注射液对缺氧性呼吸抑制的作用及其相关机制。方法：记录膈肌肌电观察缺氧后呼吸的变化,通过免疫组化的方法检测缺氧大鼠脑干酸敏感离子通道1a (ASIC1a)的表达。结果：大鼠对缺氧的呼吸反应为先兴奋后抑制。缺氧后30 min,单纯缺氧组大鼠呼吸较缺氧前表现为明显的抑制（P<0.05）,而缺氧加丹红保护组大鼠呼吸依然兴奋（P<0.05）,尚未表现出明显的抑制。大鼠脑干ASIC1a的表达主要在孤束核和斜方体核,缺氧后大鼠ASIC1a的表达较对照组明显增加（P<0.05）,但缺氧加丹红保护组大鼠ASIC1a的表达较单纯缺氧组明显减少（P<0.05）。结论：丹红注射液能明显延迟缺氧后呼吸抑制的发生,在缺氧性呼吸抑制时保护机体。ASIC1a可能参与了这一过程。     

Differential roles of hypothalamic serotonin receptor subtypes in the regulation of prolactin secretion in the turkey hen

In the turkey, exogenous serotonin (5-hydroxytryptamine, 5-HT) increases prolactin (PRL) secretion by acting through the dopaminergic (DAergic) system. In the present study, infusion of the 5-HT_2C receptor agonist, (R)(−)-DOI hydrochloride (DOI), into the third ventricle stimulates PRL secretion, whereas the 5-HT_1A receptor agonist, (+/−)-8-OH-DPAT hydrobromide (DPAT), inhibits PRL secretion. Using the immediate-early gene, c-fos, as an indicator of neuronal activity, in situ hybridization histochemistry showed preferential c-fos co-localization within tyrosine hydroxylase immunoreactive neurons (the rate limiting enzyme in DA synthesis) in the areas of the nucleus preopticus medialis (POM) and the nucleus premammillaris (PMM), in response to DPAT and DOI, respectively. To clarify the involvement of 5-HT_1A and 5-HT_2C receptors in PRL regulation, their mRNA expression was determined on hypothalamic tissue sections from birds in different reproductive stages. A significant difference in 5-HT_1A receptor was observed, with the POM of hypoprolactinemic short day and photorefractory birds showing the highest expression. 5-HT_2C receptors mRNA did not change during the reproductive cycle. The data presented support the notion that DA neurons in the PMM and POM mediate the stimulatory and inhibitory effects of 5-HT, respectively, on PRL secretion and the 5-HTergic system can both stimulate and inhibit PRL secretion.     

关节内注射氨甲环酸减少全膝关节置换术后失血的临床分析

目的探讨关节内注射氨甲环酸对人工全膝关节置换术后失血的影响。方法将50例采取单侧初次人工全膝关节置换患者,随机分为治疗组25例和对照组25例。治疗组采用关节腔内注射氨甲环酸1 000 mg,术后夹闭引流2 h,对照组采用生理盐水。术后记录术中失血量、术后引流量、血红蛋白(Hb)、红细胞压积(Hct)和输血例数、D-二聚体改变以及深静脉血栓发生例数。结果治疗组术后引流量、输血例数和D-二聚体值显著低于对照组(P0.05);治疗组血红蛋白、红细胞压积显著高于对照组(P0.05);2组均无深静脉血栓形成。结论人工全膝关节置换术后关节腔内注射氨甲环酸并夹闭引流2 h的方法能够有效减少术后失血量,同时不增加深静脉血栓发生率。     

不同来源精子对ICSI助孕结局的影响

目的探讨不同来源精子对卵胞浆内单精子注射助孕结局的影响。方法回顾分析我中心2008年1月至2012年6月1129个ICSI治疗周期,射出A组858例,附睾穿刺B组229例,睾丸穿刺C组42例,比较3组的临床结局。结果 A组年龄较B、C组大,内膜厚度薄;C组获卵数及ICSI卵数较A、B组多;B组优质胚胎率高于A组,种植率及活产率高于A、C两组（P〈0.05）。通过多元逻辑斯蒂回归模型分析精子来源与活产率的相关性,校正混杂因素后,A组相对于B组的OR值为0.559（95%CI 0.416-0.752）,C组相对于B组的OR值为0.513（95%CI 0.264-0.998）。结论附睾穿刺来源精子行ICSI可获得较好的临床结局。