Development of long-acting recombinant FVIII and FIX Fc fusion proteins for the management of hemophilia

Introduction: Prophylactic treatment with replacement clotting factor is the recommended regimen for patients with severe hemophilia to prevent bleeding episodes. However, currently available replacement clotting factors are limited by their relatively short half-lives and require intravenous injections up to three times weekly to maintain protective levels, which can impact compliance and, thus, patient outcomes.

Areas covered: The potential advantages of long-acting coagulation factors, including reduced injection frequency, increased treatment adherence, and improved clinical outcomes, are discussed. Fragment crystallizable (Fc) fusion technology is introduced and the development of long-acting recombinant factor VIII Fc (rFVIIIFc) and recombinant factor IX Fc (rFIXFc) fusion proteins for the treatment of hemophilia A and B, respectively, are described. Preclinical and clinical studies of rFVIIIFc and rFIXFc showing improved pharmacokinetics over currently available products are reviewed.

Expert opinion: Long-acting coagulation factors, including rFVIIIFc and rFIXFc, have the potential to change current paradigms of care for hemophilia A and B, respectively. Less frequent infusions may provide prolonged protection from bleeding and bleed resolution with fewer injections. In addition, long-acting coagulation factors provide an opportunity for improved individualized treatment for hemophilia.     

Contractile characteristics of gastrocnemius-soleus muscle in the SOD1G93A ALS mouse model

Abstract

Objectives:

In the SOD1G93A mouse model of amyotrophic lateral sclerosis (ALS), a selective degeneration of fast-fatigable motor units and consequently an early decline of contractile force in individual fast-twitch muscles have been observed in the preclinical stage. However, most human muscles include fast and slow motor units. Gastrocnemius-soleus group (GS) contains such a mixture of units.

Methods:

We have investigated changes in the mechanical properties of GS at different SOD1G93A stages in mice. For this purpose, the tibial nerve was repetitively stimulated with rectangular pulses and the force of GS twitches was recorded using a strain gauge fixed to the Achilles tendon.

Results:

Isometric and tetanic force were attenuated but not before the first clinical signs developed. However, already at preclinical stages, single twitches showed a slower decay compared to control. Consequently, fusion of GS twitches occurred at lower stimulus rates. Furthermore, already preclinically, the temporal course of successive twitch amplitudes changed during repetitive stimulation at increasing rates. The peak amplitudes as well as the potentiation following decay (fatigue) were lower in preclinical mice than in control.

Discussion:

The time-lapse analysis of the contractile pattern as well as of the twitch configuration of the mixed muscle GS have revealed distinctive differences between wild-type controls and preclinical SOD1G93A mice. It would be of interest to know whether these preclinical changes are also detectable in ALS patients.     

侧卧位徒手气道开放置胃管法在重症脑卒中患者的应用

目的探讨适用于重症急性脑卒中昏迷伴舌后坠、颅内压增高患者的胃管置入方法。方法将90例重症急性脑卒中昏迷患者分为3组各30例，观察组采用侧卧位徒手开放气道法，对照1组采用侧卧位置管法，对照2组采用侧卧位拉舌法，比较3组患者1次置管成功情况、不良反应程度和舌损伤情况。结果1次置管成功率，观察组高于对照1组（P<0.01），与对照2组比较差异无统计学意义（P>0.05）；不良反应程度，观察组低于对照2组（P<0.01），与对照1组比较差异无统计学意义（P>0.05）；舌损伤情况，观察组低于对照2组（P<0.05），与对照1组比较差异无统计学意义（P>0.05）。结论侧卧位徒手气道开放置胃管法，用于重症脑卒中昏迷伴舌后坠、颅内压增高患者，成功率高、刺激小、损伤轻，值得临床推广。     

Immunogenicity and therapeutic effects of recombinant Ag85AB fusion protein vaccines in mice infected with Mycobacterium tuberculosis

The immune function of tuberculosis (TB) patients is disordered. By using immune regulators to assist chemotherapy for TB the curative effect might be improved. In this study, a vaccine containing Mycobacterium tuberculosis (M. tuberculosis) recombinant Ag85AB fusion protein (rAg85AB) was constructed and evaluated. The mice were immunized intramuscularly three times at two-week intervals with Ag85AB fusion protein combined with Corynebacterium parvum adjuvant (rAg85AB+CP). In comparison to control mice that received either CP alone or saline, the mice that received rAg85AB+CP had significantly higher number of T cells secreting IFN-γ and higher levels of specific antibodies of IgG, IgG1 and IgG2a isotypes in sera. The specific antibodies also had higher ratios of IgG2a to IgG1, indicating a predominant Th1 immune response. To test for immunotherapy of TB, M. tuberculosis infected mice were given three intramuscular doses of 20 μg, 40 μg or 60 μg of rAg85AB in rAg85AB+CP, or phosphate-buffered saline (PBS), or CP or Mycobacterium phlei (M. Phlei) F.U.36. Compared with the PBS group, 20 µg, 40 µg and 60 µg rAg85AB+CP and M. phlei F.U.36 groups reduced the pulmonary bacterial loads by 0.13, 0.15, 0.42 and 0.40 log₁₀, and the liver bacterial loads by 0.64, 0.64, 0.53 and 0.61 log₁₀, respectively. Pathological changes of lungs were less, and the lesions were limited to a certain extent in 40 µg and 60 µg rAg85AB+CP and M. phlei F.U.36 groups. These results showed that rAg85AB+CP had immunotherapeutic effect on TB, significantly increasing the cellular immune response, and inhibiting the growth of M. tuberculosis.     

Accessory roots and root canals in human anterior teeth: a review and clinical considerations

Anterior teeth may have aberrant anatomical variations in the number of roots and root canals. A review of the literature was conducted using appropriate key words in major endodontic journals to identify the available reported cases as well as experimental and clinical investigations on accessory roots and root canals in anterior teeth. After retrieving the full text of related articles, cross‐citations were identified, and the pooled data were then discussed. Results revealed a higher prevalence in accessory root/root canal variations in mandibular anterior teeth than in maxillary counterparts. However, maxillary incisor teeth revealed the highest tendency for accessory root/root canal aberrations caused by anomalies such as dens invaginatus and palato‐gingival groove. Primary anterior teeth may also exhibit external and internal anatomical variations in the root, especially maxillary canines. Therefore, dental practitioners should thoroughly assess all teeth scheduled for root canal treatment to prevent the undesirable consequences caused by inadequate debridement of accessory configurations of the root canal system.     

后外侧融合与不融合在经伤椎固定治疗无脊髓损伤胸腰椎骨折中的疗效比较

目的 比较后外侧融合与不融合在经伤椎固定治疗无脊髓损伤的胸腰椎A3型骨折中的疗效. 方法 回顾性分析2001年1月至2010年10月56例无脊髓损伤的AO分型为A3型胸腰椎骨折患者的临床资料,按手术方式不同分为两组:融合组34例,男20例,女14例；平均(36.2±7.3)岁；伤椎分布:T112例,T12 10例,L1l4例,L28例,行后路复位经伤椎椎弓根螺钉内固定术,并取自体髂骨或同种异体骨行后外侧融合术；不融合组22例,男13例,女9例；平均(34.6±7.4)岁；伤椎分布:T112例,T128例,L110例,L22例,仅行后路复位经伤椎椎弓根螺钉内固定术.两组患者术前一般资料差异无统计学意义(p＞0.05),具有可比性.分别于术前、术后即刻、术后1年和术后2年随访,对两组患者的影像学指标与临床疗效进行比较.结果所有患者术后获24 ～ 84个月(平均35.6个月)的随访.两组患者手术时间[(104.1±8.5)min比(99.1±11.8) min]、出血量[(199.1 ±63.7) mL比(175.5 ±60.8) mL],术后cobb角的矫正度(13.4°±7.3°比l2.6°±4.6°)、术后2年丢失度(5.1°±4.5°比3.8°±3.9°),伤椎后凸角的矫正度(9.6°±5.1°比8.2°±3.4°)、术后2年丢失度(3.4°±2.2°比2.4°±2.7°),伤椎前、后缘高度百分比矫正度(27.5％ ± 8.6％比25.6％±10.8％),(8.4％±5.1％比7.1％±5.3％)、术后2年丢失度(5.7％±4.5％比4.8％±3.6％),(2.5％±1.7％比3.2％±1.1％),椎管矢状径复位度比较差异均无统计学意义(p＞0.05).两组患者术前、术后、术后1年和术后2年的Oswestry功能障碍指数问卷表评分与视觉模拟评分比较差异均无统计学意义(P＞ 0.05).术后除融合组l例发生断钉外,其他患者均未出现神经损伤及与伤椎置钉相关的并发症. 结论对于无脊髓损伤的胸腰椎A3型骨折,后外侧融合与不融合经伤椎椎弓根螺钉固定疗效相当.     

Neural correlates of scent marking behavior in C57BL/6J mice: detection and recognition of a social stimulus

Mice show urinary scent marking behavior as a form of social communication. Marking to a conspecific stimulus mouse or odor varies with stimulus familiarity, indicating discrimination of novel and familiar animals. This study investigated Fos immunoreactivity in inbred C57BL/6J (C57) males following scent marking behavior in response to detection of a social stimulus, or discrimination between a familiar and an unfamiliar conspecific. In Experiment 1 C57 mice were exposed for four daily trials to an empty chamber; on a test day they were exposed to the same chamber or to a male CD-1 mouse in that chamber. Increased scent marking to the CD-1 mouse was associated with increased Fos-immunoreactive cells in the basolateral amygdala, medial amygdala, and dorsal and ventral premammillary nuclei. In Experiment 2 C57 mice were habituated to a CD-1 male for 4 consecutive days and, on the 5th day, exposed to the same CD-1 male, or to a novel CD-1 male. Mice exposed to a novel CD-1 displayed a significant increase in scent marking compared to their last exposure to the familiar stimulus, indicating discrimination of the novelty of this social stimulus. Marking to the novel stimulus was associated with enhanced activation of several telencephalic, as well as hypothalamic and midbrain, structures in which activation had not been seen in the detection paradigm (Experiment 1). These included medial prefrontal and piriform cortices, and lateral septum; the paraventricular nuclei, ventromedial nuclei, and lateral area of the hypothalamus, and the ventrolateral column of the periaqueductal gray. These data suggest that a circumscribed group of structures largely concerned with olfaction is involved in detection of a conspecific olfactory stimulus, whereas discrimination of a novel vs. a familiar conspecific stimulus engages a wider range of forebrain structures encompassing higher-order processes and potentially providing an interface between cognitions and emotions.     

Functional morphology of the sound-generating labia in the syrinx of two songbird species

In songbirds, two sound sources inside the syrinx are used to produce the primary sound. Laterally positioned labia are passively set into vibration, thus interrupting a passing air stream. Together with subsyringeal pressure, the size and tension of the labia determine the spectral characteristics of the primary sound. Very little is known about how the histological composition and morphology of the labia affect their function as sound generators. Here we related the size and microstructure of the labia to their acoustic function in two songbird species with different acoustic characteristics, the white-crowned sparrow and zebra finch. Histological serial sections of the syrinx and different staining techniques were used to identify collagen, elastin and hyaluronan as extracellular matrix components. The distribution and orientation of elastic fibers indicated that the labia in white-crowned sparrows are multi-layered structures, whereas they are more uniformly structured in the zebra finch. Collagen and hyaluronan were evenly distributed in both species. A multi-layered composition could give rise to complex viscoelastic properties of each sound source. We also measured labia size. Variability was found along the dorso-ventral axis in both species. Lateral asymmetry was identified in some individuals but not consistently at the species level. Different size between the left and right sound sources could provide a morphological basis for the acoustic specialization of each sound generator, but only in some individuals. The inconsistency of its presence requires the investigation of alternative explanations, e.g. differences in viscoelastic properties of the labia of the left and right syrinx. Furthermore, we identified attachments of syringeal muscles to the labia as well as to bronchial half rings and suggest a mechanism for their biomechanical function.