锚钉结合张力带钢丝治疗髌骨下极骨折

目的研究锚钉结合张力带钢丝治疗髌骨下极骨折的疗效。方法我院于2008年3月至2009年9月采用锚钉结合张力带钢丝方法治疗髌骨下极骨折34例。术中以锚钉固定修补髌骨下极骨折块及髌韧带,并辅以胫骨结节至髌骨中上部的张力带钢丝。结果 34例患者均获12～25个月,平均17个月随访,所有骨折均愈合,2例术后出现局部浅表感染,经换药及相应抗炎治疗后愈合。陆裕朴膝关节功能评定标准评价显示,优27例,良6例,可1例,优良率为97.1%。结论锚钉结合张力带钢丝治疗髌骨下极骨折固定牢靠,并发症少,效果确切。     

Models for Antibody Behavior in Hydrophobic Interaction Chromatography and in Self-Association

Monoclonal antibodies (mAbs) form an increasingly important sector of the pharmaceutical market, and their behavior in production, processing, and formulation is a key factor in development. With data sets of solution properties for mAbs becoming available, and with amino acid sequences, and structures for many Fabs, it is timely to examine what features correlate with measured data. Here, previously published data for hydrophobic interaction chromatography and the formation of high molecular weight species are studied. Unsurprisingly, aromatic sidechain content of complementarity-determining regions (CDRs), underpins much of the variability in hydrophobic interaction chromatography data. However, this is not reflected in nonpolar solvent accessible surface enrichment at the antigen-combining site, consistent with a view in which hydrophobic interaction strength is dependent on curvature as well as on the extent of an interface. Sequence properties are also superior to surface-based structural properties in correlations with the high molecular weight species data. Combined length of CDRs is the most important factor, which could be an indication of flexibility that facilitates CDR-CDR interactions in mAb self-association. These observations couple to our understanding of protein physicochemical properties, laying the groundwork for improved developability models.     

Iterative phasing for fluctuation X-ray scattering

Fluctuation X-ray scattering (FXS) is an extension of small- and wide-angle X-ray scattering in which the X-ray snapshots are taken below rotational diffusion times. This technique, performed using a free electron laser or ultrabright synchrotron source, provides significantly more experimental information compared with traditional solution scattering methods. We develop a multitiered iterative phasing algorithm to determine the underlying structure of the scattering object from FXS data.X-ray solution scattering of macromolecular complexes is a versatile technique, providing low-resolution structural information that, when supplemented with high-resolution crystallographic data, can result in fundamental insights into the physiological behavior and function of macromolecular machines (1). Although solution scattering has been applied successfully to many problems in the biological sciences (2, 3), the technique suffers from a significant shortcoming. Due to the 3D averaging that occurs during the X-ray snapshots, the effective information content of the data is typically only around 9–15 independent parameters (4). This lack of sufficient information in the data ultimately results in nonunique or poorly determined structural hypotheses.To overcome these issues, it was proposed to perform the solution scattering process at timescales below rotational diffusion times (5, 6). By avoiding physical rotational averaging, speckle patterns emerge from which angular correlation functions can be computed. These so-called fluctuation X-ray scattering experiments can be performed on modern synchrotrons (7) and free electron laser sources (8, 9). The angular correlation information provided from these experiments is directly related to the imaged structure (10) and contains significantly more information than standard small- and wide-angle X-ray scattering (SAXS/WAXS) data. Although the relation from real space structure to fluctuation scattering data is straightforward, the inverse problem of determining a molecular model from fluctuation scattering data is nontrivial (8).For 2D systems, such as macromolecules randomly oriented around a single axis (11), an analytical route for image reconstruction is available (12). However, this approach requires triple correlation measurements across the full resolution range of interest, which may not be fully accessible due to experimental limitations.Earlier work attempting to determine 3D shape from fluctuation scattering data was based on solving two phase problems consecutively. Although this route has shown success in cases where the scattering species has helical (13) or icosahedral symmetry (14), it fails to produce a structure for the general case. Another approach was developed in which the inverse problem was solved using a reverse Monte Carlo method (8), similar to what is used to determine macromolecular envelopes from SAXS data (15–17). Although this approach allows a real space object to be reconstructed without the need for symmetry constraints, the procedure is computationally expensive and, in general, convergence can be problematic (18). Furthermore, the existing reverse Monte Carlo method assumes a binary model, where voxels either have a scattering length or do not. The breakdown of this uniform density assumption ultimately limits the resolution of features that can be reconstructed through such an approach.Here we develop a fundamentally different approach to structure solution from fluctuation scattering, based on a multitiered iterative phasing (MTIP) algorithm. In particular, we derive a series of projection operators, which are used to iteratively modify a model to satisfy specified real space constraints and match the derived model fluctuation scattering data to external observations. This approach does not require a uniform density assumption and solves the two inherent phase problems concurrently, which allows one to obtain a reconstruction with a reduced amount of fluctuation scattering data, or even SAXS/WAXS data alone, by compensating with the extra information provided through real space constraints.The presented method allows one to study the structure of objects that cannot be easily crystallized, while achieving higher resolution than what is possible through standard SAXS/WAXS experiments. As a result, this approach can be used to gain deeper insight into biological structure and to expand the range of characterization methods for nanostructures (19). Furthermore, the framework developed here allows one to extend many of the density modification techniques developed for crystallography to solution scattering.     

Endogenous fungal endophthalmitis: risk factors, clinical course, and visual outcome in 13 patients

AIM:To analyze the risk factors,ophthalmological features,treatment modalities and their effect on the visual outcome in patients with endogenous fungal endophthalmitis(EFE).METHODS:Data retrieved from the medical files included age at presentation to the uveitis clinic,gender,ocular symptoms and their duration before presentation,history of fever,eye affected,anatomical diagnosis and laboratory evidence of fungal infection.Medical therapy recorded included systemic antifungal therapy and its duration,use of intravitreal antifungal agents and use of oral/intravitreal steroids.Surgical procedures and the data of ophthalmologic examination at presentation and at last follow-up were also collected.RESULTS:Included were 13 patients(20 eyes,mean age 58 y).Ten patients presented after gastrointestinal or urological interventions and two presented after organ transplantation.In one patient,there was no history of previous intervention.Diagnostic vitrectomy was performed in 16 eyes(80%)and vitreous cultures were positive in 10 of the vitrectomized eyes(62.5%).In only 4 patients(31%),blood cultures were positive.All patients received systemic antifungal therapy.Sixteen eyes(80%)received intravitreal antifungal agent with voriconazole being the most commonly used.Visual acuity(VA)improved from 0.9±0.9 at initial exam to 0.5±0.8 logMAR at last followup(P=0.03).A trend of greater visual improvement was noted in favor of eyes treated with oral steroids(±intravitreal dexamethasone)than eyes that were not treated with steroids.The most common complication was maculopathy.Twelve eyes(60%)showed no ocular complications.CONCLUSION:High index of suspicion in patients with inciting risk factors is essential because of the low yield of blood cultures and the good general condition of patients at presentation.Visual prognosis is improved with the prompt institution of systemic and intravitreal pharmacotherapy and the immediate surgical intervention.Oral±local steroids could be considered in cases of prolonged or marked inflammatory responses in order to hasten control of inflammation and limit ocular complications.     

Treatment of Patellar Lower Pole Fracture with Modified Titanium Cable Tension Band Plus Patellar Tibial Tunnel Steel “8” Reduction Band

Abstract

Purpose: To determine the efficacy of modified titanium tension band plus patellar tendon tunnel steel 8 “reduction band” versus titanium cable tension band fixation for the treatment of patellar lower pole fracture. Materials and Methods: 58 patients with lower patella fracture were enrolled in this study, including 30 patients treated with modified titanium cable tension band plus patellar tibial tunnel wire “8” tension band internal fixation (modified group), and 28 patients with titanium cable tension band fixation. All patients were followed up for 9～15 months with an average of 11.6 months. Results: Knee flexion was significantly improved in the modified group than in the titanium cable tension band group (111.33 ± 13 degrees versus 98.21 ± 21.70 degrees, P = 0.004). The fracture healing time showed no significant difference. At the end of the follow-up, the improvement excellent rate was 93.33% in the modified group, and 82.14% in the titanium cable tension band group. Titanium cable tension band internal fixation loosening was found in 2 cases, including 1 case of treatment by two surgeries without loose internal fixation. Conclusions: The modified titanium cable tension band with “8” tension band fixation showed better efficacy for lower patella fractures than titanium cable tension band fixation.     

OCT及视野极性分析图检测对早期慢性青光眼诊断价值

目的 应用光学相干断层扫描技术（OCT）及视野极性分析图,检测慢性青光眼视网膜神经纤维层（RNFL）厚度和视野缺损情况,分析两者的相关性及其在早期慢性青光眼诊断中的价值。方法 采用海德堡Spectralis OCT对42例（62只眼）青光眼（包括15例原发性开角型青光眼和27例慢性闭角型青光眼）病人颞上方、鼻上方、颞侧、鼻侧、颞下方、鼻下方RNFL厚度进行测量,计算RNFL出现缺损的阳性率,OCTOPUS 900全自动视野计进行视野检查,采用极性分析图观察相应区域有无视野缺损,并计算其阳性率。结果 OCT检测早期慢性青光眼病人颞上方、鼻上方、颞侧、鼻侧、颞下方、鼻下方RNFL损伤阳性率分别为54.8%、29.0%、30.6%、29.0%、54.8%、30.6%,其中颞上方和颞下方RNFL缺损的阳性率较高（χ^2=21.96,P〈0.001）;而极性分析图检测各象限视野缺损阳性率分别为96.8%、64.5%、91.9%、30.1%、98.3%、61.2%,颞上方和颞下方阳性率较高（χ^2=28.35,P〈0.001）,与OCT检查结果具有较好的一致性,两种检测方法颞上方、鼻上方、颞侧、颞下方及鼻下方阳性率比较差异有显著性（χ^2=14.08～26.10,P〈0.001）。OCT及视野极性分析图均表现出鼻侧阳性率较低,且两者的阳性率相比差异无显著性（P＞0.05）。结论 视野极性分析图检测视野缺损与OCT检测RNFL变化具有较好的一致性,极性分析图是评估与随访青光眼病人RNFL结构与功能的桥梁,可能为临床早期诊断青光眼提供更多的信息。     

Synergies between climate and management for Atlantic cod fisheries at high latitudes

The widespread depletion of commercially exploited marine living resources is often seen as a general failure of management and results in criticism of contemporary management procedures. When populations show dramatic and positive changes in population size, this invariably leads to questions about whether favorable climatic conditions or good management (or both) were responsible. The Barents Sea cod (Gadus morhua) stock has recently increased markedly and the spawning stock biomass is now at an unprecedented high. We identify the crucial social and environmental factors that made this unique growth possible. The relationship between vital rates of Barents Sea cod stock productivity (recruitment, growth, and mortality) and environment is investigated, followed by simulations of population size under different management scenarios. We show that the recent sustained reduction in fishing mortality, facilitated by the implementation of a “harvest control rule,” was essential to the increase in population size. Simulations show that a drastic reduction in fishing mortality has resulted in a doubling of the total population biomass compared with that expected under the former management regime. However, management alone was not solely responsible. We document that prevailing climate, operating through several mechanistic links, positively reinforced management actions. Heightened temperature resulted in an increase in the extent of the suitable feeding area for Barents Sea cod, likely offering a release from density-dependent effects (for example, food competition and cannibalism) through prolonged overlap with prey and improved adult stock productivity. Management and climate may thus interact to give a positive outlook for exploited high-latitude marine resources.Unsustainable harvest of marine fisheries resources is frequently reported as a worldwide problem (1, 2) with important socioeconomic (3, 4) and ecological implications (5). Some question whether proper management is even feasible given the assessment tools available and the common disparity between management advice and landings, where the setting of allowable catch is the result of multiple processes, including political ones (6). Prevailing harvesting regimes have also been challenged (7) and contemporary management procedures of many of the world’s leading fisheries nations indirectly criticized (8). Assessment tools are unfortunately limited in the amount of complexity (or biological realism) that can be included, even though it is known that stock dynamics result from the interplay of multiple factors acting on the population, each of which can cause fundamentally different responses (9–12).Fishing has a strong and direct influence on both total and spawning stock biomass (Fig. S1), through reductions in older fish, spatial contraction of the population, potential loss of subpopulations, alteration of life history traits, and habitat damage (13). Meanwhile, a main effect of climate change is to displace the geographical range of organisms, also including fish (refs. 14–16 and Fig. S1). Climate is also known to directly affect individuals through growth, natural mortality, and food availability and indirectly by affecting spawning times or influencing the choice of spawning grounds (Fig. S1). Other indirect effects may include the advection of key prey items from one area to another (i.e., displacement) or changes to system productivity (17). Because of the different ecological responses, a population may react immediately to a climate signal or, because there are often several physical or biological intermediary steps between the forcing and the ecological trait, have a temporally delayed (lagged) response (11, 18). These complex interactions may cause unexpected disruptions in the ability of a population to withstand or adjust to climate changes, cause populations to become more sensitive to climate variability at interannual to interdecadal scales (9), or cause fishery management schemes to have unexpected results (10). Hence, it is probably impossible to completely disentangle the effects of fisheries and climate on population.Management plans for fish stocks usually include a number of measures such as regulation of total allowable catch (TAC, a quota) as well as technical regulations and estimations of uncertainty. The criteria used for deciding the TAC is often denoted as a harvest control rule (HCR). Although structurally simple, applications of HCRs are considered advanced management tools (19), especially when containing ecosystem-based elements (20). HCRs aim to regulate fishing effort so that the full stock reproductive potential (SRP) is maintained and the population is kept at the size allowing the highest possible harvest under continued exploitation in the long term (i.e., maximum sustainable yield). Social issues, for example, fishers’ involvement, are also important for the success of management plans (21). The first application of HCRs appeared in the 1990s (19).The commercially valuable Barents Sea (BS) cod (Gadus morhua), also referred to as Northeast Arctic cod, population has increased greatly in size in recent years, which has coincided with environmental (e.g., temperature) and fisheries’ policy changes. A key management development for the BS cod was the introduction of an HCR in 2004 (22) (further details are given in SI Materials and Methods) and a total discard ban. However, this HCR did not come into full effect until illegal, unreported, and unregulated catches were reduced in 2006 and then largely eliminated in 2009. In the following analyses, we used 2007 as the year of implementation because that was the year when fishing mortality (F) was reduced to the level intended in the described management plan. One important consequence of this agreed plan has been that catches have remained within scientific guidelines during the increase in stock biomass.Could favorable climatic conditions (Fig. 1A) alone have resulted in the recent increases in total stock biomass (TSB) and spawning stock biomass (SSB) for BS cod (Fig. 1B), or has management also contributed? Have BS managers simply been “lucky” compared with, for instance, managers involved with the Northern cod collapse off Newfoundland (23)? Assuming that the recent warmer regime did not play a role seems unrealistic; temperature is generally positively associated with TSB for BS cod (Fig. 1 A and B). Climate has the potential to influence cod population dynamics through multiple links (Fig. S1), but disentangling exact mechanisms is difficult. For example, ambient temperature influences biochemical processes for ectotherms (24), but changing fish distributions make the link between regional and ambient temperature difficult to analyze or predict. We therefore assessed the impact of climate and management on BS cod population size in three different ways. First, we investigated how the principal “drivers” of BS cod stock productivity (Fig. 2) related to ocean temperature and spatial distribution, more specifically suitable feeding area extent (SFA), a less common metric in relation to climate effects studies. Second, we modeled what would have happened if the HCR (i) had never been implemented and (ii) had been implemented in 1993 (i.e., at the beginning of a period of stable growth and mortality). Finally, the consequence of the actual 2007 HCR implementation on fishing patterns was evaluated by studying the development in F for young (3, 4) and older (5–10) age classes.Open in a separate windowFig. 1.Both environmental conditions and cod stock metrics have fluctuated greatly in the Barents Sea ecosystem over time. (A–C) Shaded area indicates the HCR implementation period (2007–2013). (A) Nine-year smoothed Kola temperature (red) (1900–2012) and suitable feeding area extent (black) (1970–2012), with real data plotted as points during the HCR implementation period. (B) Trends in spawning stock biomass (blue) and total biomass (black) (1913–2012). Actual biomass (solid, thick line) refers to the measured biomass of the population, and simulated HCR (solid, thin line) was estimated as if the HCR had been introduced in 1993. No HCR (dotted line) reflects biomass development under no HCR implementation. (C) Landings under the different harvest scenarios (1900–2012).Open in a separate windowFig. 2.The BS cod production has peaked several times since WWII but is significantly higher today if standardized per unit biomass. (A) Overview of BS cod annual production, recruitment, natural mortality, and catch (1946–2010). (B) Corresponding surplus and net production. The difference between surplus production and net production reflects landings. (C) Surplus production per unit biomass in relation to spawning stock biomass for the periods 2000–2010 (filled circle and solid line) and 1946–1999 (open circle and dashed line) (ANCOVA, n = 65).     

Effect of surface properties on the antithrombogenicity of silk fibroin/S-carboxymethyl kerateine blend films

Polymeric blends of silk fibroin (SF) and S-carboxymethyl kerateine (SCMK) were prepared by the solvent casting method to study the effect of surface properties on the antithrombogenicity. The films of SF/SCMK showed better antithrombogenic properties than SF or SCMK alone. Among them, the film containing 50 wt% SCMK showed the best antithrombogenicity. When the SF/SCMK films were treated with methanol, the antithrombogenicity of the films was scarcely affected except the SF-rich ones. The enhanced antithrombogenic properties were explained in terms of polarity of the surface. The blend films showed an enhancement of polar contribution to surface free energy (γ_S ^P) and polar stabilization energy (I_sw). SF-rich films showed high γ^P _S and I_sw values when treated with methanol. This change of surface properties was considered to be due to the fact that the conformational transition from random coil structure to β-structure of proteins may have affected the surface properties, especially the polar properties.