BACKGROUND & AIMS: :A transmembrane extracellular matrix receptor of the integrin family, alpha 6 beta 4, is a component of the hemidesmosome, an adhesion complex of importance in epithelial cell-connective tissue attachment (Stepp, M. A., S. Spurr-Michaud, A. Tisdale, J. Elwell, and I. K. Gipson. 1990. Proc. Natl. Acad. Sci. USA. 87:8970-8974; Jones, J. C. R., M. A. Kurpakus, H. M. Cooper, and V. Quaranta. 1991. Cell Regulation. 2:427-438). Cytosolic components of hemidesmosomes include bullous pemphigoid (BP) antigens while extracellular components include a 125-kD component of anchoring filaments (CAF) and collagen type VII-containing anchoring fibrils. We have monitored the incorporation of the alpha 6 beta 4 integrins into forming hemidesmosomes in an in vitro wound-healing explant model. In epithelial cells recently migrated from the edges of unwounded sites over bare connective tissue, alpha 6 beta 4 first appears along the entire cell surface. At this stage, these cells contain little or no cytosolic hemidesmosomal components, at least as detectable by immunofluorescence using BP autoantibodies, whereas they are already positive for laminin and CAF. At a later stage, as cells become positive for cytosolic hemidesmosome components such as BP antigens as well as collagen type VII, alpha 6 beta 4 becomes concentrated along the basal pole of the epithelial cell where it abuts the connective tissue of the explant. Polyclonal antibodies to beta 4 do not interfere with the migration of epithelial cells in the explant. However, they prevent assembly of hemidesmosomal complexes and inhibit expression of collagen type VII in cells that have migrated over wound areas. In addition, they induce disruption of established hemidesmosomes in nonmigrating cells of the unwounded area of the explant. Monoclonal antibodies to alpha 6 have a more dramatic effect, since they completely detach epithelial cells in the unwounded area of the explant. Antibodies to CAF also detach epithelial cells in unwounded areas, apparently by inducing separation between epithelium and connective tissue at the lamina lucida of the basement membrane zone. These results suggest a model whereby polarization of alpha 6 beta 4 to the basal surface of the cells, perhaps induced by a putative anchoring filament-associated ligand, triggers assembly of hemidesmosome plaques.

背景与目标： : 整联蛋白家族的跨膜细胞外基质受体 α6β4是半染色体的组成部分，半染色体是上皮细胞-结缔组织附着中重要的粘附复合物 (Stepp，m.a.，S. Spurr-Michaud，A. Tisdale，J. Elwell，和I. K. Gipson。1990. Proc. Natl. Acad. Sci.美国。87:8970-8974; Jones，j.c.R.，M.Kurpakus，H. M. Cooper和V. Quaranta。1991.细胞调控。2:427-438)。半桥粒的胞质组分包括大疱性类天疱疮 (BP) 抗原，而细胞外组分包括锚定细丝 (CAF) 的125-kD组分和含VII型胶原的锚定原纤维。我们已经在体外伤口愈合外植体模型中监测了 α6β4整合素在形成半桥体中的掺入。在最近从裸露的结缔组织上未受伤部位的边缘迁移的上皮细胞中，α6β4首先出现在整个细胞表面。在这个阶段，这些细胞含有很少或没有胞质半染色体成分，至少可以通过使用BP自身抗体的免疫荧光检测到，而它们已经对层粘连蛋白和CAF呈阳性。在稍后的阶段，随着细胞对胞质半桥粒成分 (例如BP抗原) 以及VII型胶原呈阳性，α6β4沿着上皮细胞的基极集中，并与外植体的结缔组织邻接。针对 β4的多克隆抗体不会干扰外植体中上皮细胞的迁移。但是，它们阻止了半桥粒复合体的组装，并抑制了在伤口区域迁移的细胞中VII型胶原的表达。此外，它们还会诱导外植体未受伤区域的非迁移细胞中已建立的半桥粒的破坏。针对 α6的单克隆抗体具有更显着的作用，因为它们完全脱离了外植体未受伤区域的上皮细胞。针对CAF的抗体也可以通过诱导基底膜区的上皮和结缔组织之间的分离而分离未受伤区域的上皮细胞。这些结果提出了一个模型，其中 α6β4极化到细胞的基底表面，可能是由假定的锚定细丝相关配体诱导的，触发了半桥粒斑块的组装。

BACKGROUND & AIMS: :The environmental mobility of newly deposited radionuclides in surface soil is driven by complex biogeochemical relationships, which have significant impacts on transport pathways. The partition coefficient (Kd) is useful for characterizing the soil-solution exchange kinetics and is an important factor for predicting relative amounts of a radionuclide transported to groundwater compared to that remaining on soil surfaces and thus available for transport through erosion processes. Measurements of Kd for 238U are particularly useful because of the extensive use of 238U in military applications and associated testing, such as done at Los Alamos National Laboratory (LANL). Site-specific measurements of Kd for 238U are needed because Kd is highly dependent on local soil conditions and also on the fine soil fraction because 238U concentrates onto smaller soil particles, such as clays and soil organic material, which are most susceptible to wind erosion and contribute to inhalation exposure in off-site populations. We measured Kd for uranium in soils from two neighboring semiarid forest sites at LANL using a U.S. Environmental Protection Agency (EPA)-based protocol for both whole soil and the fine soil fraction (diameters<45 microm). The 7-d Kd values, which are those specified in the EPA protocol, ranged from 276-508 mL g-1 for whole soil and from 615-2249 mL g-1 for the fine soil fraction. Unexpectedly, the 30-d Kd values, measured to test for soil-solution exchange equilibrium, were more than two times the 7-d values. Rates of adsorption of 238U to soil from solution were derived using a 2-component (FAST and SLOW) exponential model. We found significant differences in Kd values among LANL sampling sites, between whole and fine soils, and between 7-d and 30-d Kd measurements. The significant variation in soil-solution exchange kinetics among the soils and soil sizes promotes the use of site-specific data for estimates of environmental transport rates and suggests possible differences in desorption rates from soil to solution (e.g., into groundwater or lung fluid). We also explore potential relationships between wind erosion, soil characteristics, and Kd values. Combined, our results highlight the need for a better mechanistic understanding of soil-solution partitioning kinetics for accurate risk assessment.

背景与目标： : 新沉积的放射性核素在表层土壤中的环境迁移率是由复杂的生物地球化学关系驱动的，这些关系对运输途径有重大影响。分配系数 (Kd) 可用于表征土壤溶液交换动力学，并且是预测输送到地下水的放射性核素与残留在土壤表面的放射性核素的相对量相比的重要因素，因此可用于通过侵蚀过程进行运输。238U的Kd测量特别有用，因为238U在军事应用和相关测试中广泛使用，例如在洛斯阿拉莫斯国家实验室 (LANL) 进行的。需要对238U进行特定地点的Kd测量，因为Kd高度依赖于当地土壤条件，也高度依赖于精细的土壤分数，因为238U集中在较小的土壤颗粒上，例如粘土和土壤有机材料，这些颗粒最容易受到风蚀的影响并有助于异地人群的吸入暴露。我们使用基于美国环境保护局 (EPA) 的协议，针对整个土壤和细土部分 (直径 <45微米)，测量了LANL两个相邻的半干旱森林站点土壤中铀的Kd。EPA协议中指定的7-d Kd值的范围为整个土壤的g-1为276-508 mL，而细土部分的g-1为615-2249 mL。出乎意料的是，为测试土壤溶液交换平衡而测得的30 d Kd值是7-d值的两倍以上。使用2组分 (快速和慢速) 指数模型得出溶液中238U对土壤的吸附率。我们发现LANL采样点之间，整个土壤和细土之间以及7-d和30d Kd测量值之间的Kd值存在显着差异。土壤之间的土壤溶液交换动力学和土壤大小的显着变化促进了使用特定地点的数据来估算环境迁移速率，并暗示了从土壤到溶液 (例如，进入地下水或肺液) 的解吸速率可能存在差异。我们还探讨了风蚀，土壤特征和Kd值之间的潜在关系。结合起来，我们的结果强调了需要对土壤溶液分配动力学进行更好的机械理解，以进行准确的风险评估。

BACKGROUND & AIMS: :Facile fabrication of nanostructured surface is of great importance for the use of titanium (Ti) implants in biomedical field. In this study, a low-cost and easy-to-operate method called HPT (hydrothermal & pressure) here has been developed and used to fabricate the expected nanostructured surface on Ti substrates. The effects of experimental parameters on the morphology of Ti surface were investigated and characterized. The results indicated that by altering the hydrothermal pressure, NaOH concentration and treating time, surface nanostructure like nanopetals or nanoflakes could be formed on the surface of Ti substrates. The orthogonal experiments were conducted to demonstrate the optimized operation conditions. A formation mechanism of the nanostructured titanate layer was proposed, revealing that the nanostructured layer could be formed via a special upward and downward co-growth manner. In vitro cell culture showed that the HPT treated Ti substrates, especially the T-10 sample, could greatly enhance the cell-material interactions, i.e. the cell proliferation and differentiation, focal protein adhesion, and osteogenic factor expression. The HPT method paves a new way to modify the surface of Ti implants with better bioactivity and promising prospect for future biomedical applications.

背景与目标： : 纳米结构表面的简便制造对于在生物医学领域中使用钛 (Ti) 植入物非常重要。在这项研究中，已经开发了一种称为HPT (水热 & 压力) 的低成本且易于操作的方法，并将其用于在Ti衬底上制造预期的纳米结构表面。研究并表征了实验参数对Ti表面形貌的影响。结果表明，通过改变水热压力，NaOH浓度和处理时间，可以在Ti基材表面形成类似纳米颗粒或纳米薄片的表面纳米结构。进行正交实验以证明优化的操作条件。提出了纳米结构钛酸盐层的形成机理，揭示了纳米结构层可以通过特殊的向上和向下共生长方式形成。体外细胞培养表明，经HPT处理的Ti底物，尤其是T-10样品，可以大大增强细胞与物质的相互作用，即细胞增殖和分化，聚焦蛋白粘附和成骨因子的表达。HPT方法为修饰Ti植入物表面提供了一种新方法，具有更好的生物活性，并有望在未来的生物医学应用中获得广阔的前景。

BACKGROUND & AIMS: :We investigated the conditions under which inhomogeneity in electrical conductivity may significantly modify the magnetic evoked field (MEF) due to primary currents (i.e., neuronal currents) in the brain. In the case of an isolated turtle cerebellum immersed in a large bath of physiological saline, our theoretical analysis showed the cerebellar surface to significantly enhance the MEF due to a primary current, by a factor of as much as two, for experimentally determined values of the conductivities of the cerebellar tissue and saline. A further parametric investigation of the conductivity effect revealed that conductivity boundaries may significantly modify the MEF due to neuronal currents located within 1 mm of a conductivity boundary, as would be the case for active neurons near an edema, an anoxic fringe such as might occur during stroke, or a ventricle in the human head. For a stationary neural source, conductivity boundaries may modify the magnitude of its MEF without affecting its temporal waveform. However, this boundary effect was found to be small for a model geometry locally approximating cortical sources in a sulcus or a fissure, where the boundary effects from adjacent sulcal walls tend to cancel each other.

背景与目标： : 我们研究了电导率不均匀性可能会由于大脑中的主要电流 (即神经元电流) 而显着改变磁诱发场 (MEF) 的条件。如果将孤立的乌龟小脑浸入一个大的生理盐水浴中，我们的理论分析表明，由于一次电流，小脑表面显着提高了MEF，对于实验确定的小脑组织和盐水的电导率值，其系数高达两倍。对电导率效应的进一步的参数研究表明，由于位于电导率边界的1毫米内的神经元电流，电导率边界可能会显著地改变MEF，如在水肿、缺氧边缘 (例如在中风期间可能发生) 或人头部的心室附近的活动神经元的情况。对于固定神经源，电导率边界可能会改变其MEF的大小，而不会影响其时间波形。然而，对于局部近似于沟或裂缝中的皮质源的模型几何，发现这种边界效应很小，其中相邻沟壁的边界效应趋于相互抵消。

BACKGROUND & AIMS: :The aim of this study was to assess the frequencies and patterns of naturally occurring genotypic resistance to nucleos(t)ide analogues (NUCs) and typical hepatitis B surface antigen (HBsAg) amino acid substitutions in naive hemodialysis (HD) patients with chronic hepatitis B. In order to achieve this, the genotypic resistance to NUCs and HBsAg amino acid substitutions were classified into primary/compensatory resistance mutation and antiviral drug-associated potential vaccine-escape mutation (ADAPVEM)/typical HBsAg amino acid substitution, respectively. Direct sequencing of polymerase (pol) gene of hepatitis B virus (HBV) was performed on DNA samples obtained from 248 HBsAg-positive Turkish patients. Overall, 38% (n = 94) of HBsAg-positive HD patients had detectable HBV DNA in their serum. Naturally occurring primary and compensatory resistance mutations to NUCs were detected in 30% (n = 28) and 52% (n = 49) of HD patients, respectively. However, 6 types of ADAPVEMs and 48 types of typical HBsAg amino acid substitutions were found in 10.6% (n = 10) and 46% (n = 43) of the HD patients, respectively. Our study suggests that every HD patient diagnosed with chronic hepatitis B, who is a potential candidate for NUCs treatment, should also be monitored for the baseline pol gene sequence changes before the initial treatment, for a more effective management of future treatment options. Further, a relatively higher frequency of ADAPVEMs variants needs to be addressed as a public health problem.

背景与目标： : 这项研究的目的是评估天然发生的基因型对核苷 (酸) 类似物 (NUCs) 和典型乙型肝炎表面抗原 (HBsAg) 氨基酸替代的频率和模式在幼稚血液透析 (HD) 患者慢性乙型肝炎。为了实现这一目标，将对NUCs和HBsAg氨基酸取代的基因型抗性分别分为原发性/代偿性耐药突变和抗病毒药物相关潜在的疫苗逃逸突变 (ADAPVEM)/典型HBsAg氨基酸取代。乙型肝炎病毒 (HBV) 的聚合酶 (pol) 基因的直接测序是从248 HBsAg阳性土耳其患者获得的DNA样品。总体而言，38% (n = 94) HBsAg阳性HD患者的血清中可检测到HBV DNA。分别在30% (n = 28) 和52% (n = 49) 的HD患者中检测到自然发生的对NUCs的原发性和代偿性耐药突变。然而，在HD患者的10.6% (n = 10) 和46% (n = 43) 中分别发现了6种类型的ADAPVEMs和48种类型的典型HBsAg氨基酸取代。我们的研究表明，每个HD患者诊断为慢性乙型肝炎，谁是NUCs治疗的潜在候选者，也应该监测基线pol基因序列变化之前的初始治疗，以更有效地管理未来的治疗选择。此外，需要将相对较高的ADAPVEMs变体频率作为公共卫生问题来解决。

BACKGROUND & AIMS: :The cleanability of titanium and 316L stainless steel particles was studied in terms of their apparent surface charge density (sigma(app)). Bovine serum albumin (BSA) was used as the model fouling agent. Curves for the sigma(app) of titanium and stainless steel particles showed the apparent points of zero charge (pzc(app)) of 4.6 and 8.5, respectively. Compared with the curve for the sigma(app) of stainless steel, that of titanium was characterized by small positive and large negative sigma(app) values. The isotherms for BSA adsorption and the saturation amount of BSA adsorbed on titanium and stainless steel depended largely on the intrinsic properties of BSA. In continuous cleaning in a plug-flow column fed by a 0.05M NaOH solution, BSA was found to be faster desorbed from titanium than from stainless steel, and smaller amounts of BSA remaining after 120-min cleaning were observed on titanium. Kinetic analysis showed that the two first-order desorption rate constants, reflecting the rate of BSA desorption in the initial and later stages of cleaning, for titanium were respectively 1.7-fold and 1.3-fold higher than those values for stainless steel. It could be suggested that the better cleanability of titanium was probably due to the small binding strength of BSA on slightly negatively-charged titanium surfaces and due to their large negative sigma(app) values under alkaline cleaning conditions.

背景与目标： : 根据钛和316L不锈钢颗粒的表观表面电荷密度 (sigma(app)) 研究了其可清洗性。牛血清白蛋白 (BSA) 用作模型结垢剂。钛和不锈钢颗粒的sigma(app) 曲线分别显示了4.6和8.5的零电荷 (pzc(app)) 的表观点。与不锈钢的sigma(app) 曲线相比，钛的特征是正负sigma(app) 值小。BSA吸附的等温线和BSA吸附在钛和不锈钢上的饱和度在很大程度上取决于BSA的固有性能。在由0.05M NaOH溶液进料的活塞流柱中连续清洗中，发现BSA从钛解吸比从不锈钢解吸更快，并且在钛上观察到120分钟清洗后剩余的BSA的量较少。动力学分析表明，钛的两个一级解吸速率常数 (反映了清洁初期和后期BSA解吸速率) 分别比不锈钢高1.7倍和1.3倍。可以认为，钛的更好的清洁性可能是由于BSA在带负电的钛表面上的结合强度较小，以及在碱性清洁条件下它们的负 σ (app) 值较大。

BACKGROUND & AIMS: BACKGROUND/PURPOSE:Several anti-viral drugs are approved for the treatment of hepatitis B virus (HBV) infection. However, whether quantitative hepatitis B surface antigen (qHBsAg) can predict the therapeutic response during long-term entecavir treatment remains unclear. METHODS:Fifty-five chronic hepatitis B (CHB) patients who received entecavir for more than 2 years were enrolled. The serum qHBsAg level was measured by HBsAg II quant immunoassay. A significant decline in the qHBsAg level was defined as > 1 log reduction from baseline to 6 months of entecavir treatment. RESULTS:Of the 55 patients (41 males and 14 females with a mean age of 48.3 ± 11.4 years), 23 patients were positive for hepatitis B e antigen (HBeAg). The median treatment period was 34 months, and ranged from 26 months to 43 months. A total of 288 serum samples were used to determine the qHBsAg levels. At year 3 of entecavir therapy, one (1.8%) patient had HBsAg seroclearance. A high qHBsAg level was defined as greater than 10,000 IU/mL. Patients with a high baseline qHBsAg level had a lower rate of virologic response at year 1 (37.5% vs. 89.7%, p < 0.001) and year 2 (56.2% vs. 94.9%, p = 0.001). In this study population, 14.5% had a significant decline of the qHBsAg level. A significant decline could not predict HBeAg loss in HBeAg-positive or virologic response in all patients. CONCLUSION:The baseline serum qHBsAg level can predict virologic response in entecavir-treated CHB patients. However, a significant decline in the qHBsAg level cannot predict serologic or virologic response of entecavir treatment.

背景与目标：

BACKGROUND & AIMS: :Intervertebral disc spacers using bioactive ceramics have been used to treat degenerative spinal disease. Tooth-shaped spacers are commonly used to prevent migration, but there is a possibility of fracture when inserted or after insertion. Intervertebral disc spacers with either an isosceles triangle-shaped tooth (T1) or a right triangle-shaped tooth (T2) were used as a control group. The design factors for the experimental group were modified to prevent fractures induced by stress concentration, and the surfaces of the spacers were designed as either an isosceles triangle-shaped valley (V1) or a right triangle-shaped valley (V2). Linear analysis using finite element model (FEM) was performed, and Von Mises stress distribution was calculated by applying 1000 N of uniformly distributed load. Samples of the V2 design were made with bioactive glass-ceramics (BGS-7) and evaluated for compressive strength, fatigue degree, and impact strength. Von Mises stress was highest at the first tooth from the posterior side for the control group and at the center for the experimental group. Compared with the control group, the experimental group showed 18.4% and 82.5% reduction (V1 vs. T1 and V2 vs. T2, respectively) in the maximum stress at the bottom of the valleys. The FEM analysis revealed that the V2 design had the most even load distribution. The V2 samples with bioactive glass-ceramics were evaluated for compressive strength, and all six samples were not fractured up to 24 000 N. However, the average impact strength was 19.42 kN, suggesting that momentary force caused damage at a lower load than compression with a steady speed. The BGS-7 intervertebral disc spacer with V2 design was not fractured during the fatigue test at maximum pressure of 8000 N, R ≥10, 5 Hz, and 5 million cycles. These data confirm that the BGS-7 spacer with the V2 design may be clinically applicable. Collectively, the modified surface geometry of the experimental group significantly lowered Von Mises stress values at the bottom of the valleys, and thus the possibility of fracture by compressive load was greatly reduced. Also, impact during insertion was confirmed to cause fracture more easily, as the impact strength was lower than the compressive strength in the experimental group.

背景与目标： : 使用生物活性陶瓷的椎间盘垫片已用于治疗退行性脊柱疾病。通常使用齿形垫片来防止迁移，但是插入时或插入后有断裂的可能性。将具有等腰三角形牙齿 (T1) 或直角三角形牙齿 (T2) 的椎间盘间隔物用作对照组。修改了实验组的设计因素，以防止应力集中引起的裂缝，并将垫片的表面设计为等腰三角形谷 (V1) 或直角三角形谷 (V2)。使用有限元模型 (FEM) 进行线性分析，并通过1000 N均匀分布的载荷计算Von Mises应力分布。用生物活性玻璃陶瓷 (BGS-7) 制成V2设计的样品，并评估其抗压强度，乏力程度和冲击强度。对照组从后侧开始的第一颗牙齿和实验组的中心位置的Von Mises应力最高。与对照组相比，实验组在谷底的最大应力显示出18.4% 和82.5% 的降低 (分别为V1对T1和V2对T2)。有限元分析表明，V2设计的载荷分布最均匀。评估了具有生物活性微晶玻璃的V2样品的抗压强度，并且所有六个样品的断裂都达到24 000 N。但是，平均冲击强度为19.42 kN，这表明瞬时力在比稳定速度的压缩低的载荷下引起损坏。在最大压力为8000 N，R ≥ 10、5Hz和500万个循环的疲劳试验中，采用V2设计的BGS-7椎间盘垫片没有断裂。这些数据证实具有V2设计的BGS-7间隔物可以在临床上适用。总的来说，实验组的修改后的表面几何形状显着降低了谷底部的Von Mises应力值，因此大大降低了压缩载荷导致断裂的可能性。此外，由于插入过程中的冲击强度低于实验组的抗压强度，因此确认插入过程中的冲击更容易导致断裂。

BACKGROUND & AIMS: :We investigated immunoglobulin G (IgG) subclass antibody responses to Plasmodium falciparum merozoite surface protein 1 (MSP-1) and MSP-2 in 112 malaria-exposed subjects in Brazil. IgG3 polarization was primarily epitope driven, being little affected by cumulative or current exposure to malaria and not affected by a subject's age and Fcgamma receptor IIA genotype.

背景与目标： : 我们调查了巴西112名疟疾暴露受试者对恶性疟原虫裂殖子表面蛋白1 (MSP-1) 和MSP-2的免疫球蛋白G (IgG) 亚类抗体反应。IgG3极化主要是表位驱动的，几乎不受累积或当前暴露于疟疾的影响，并且不受受试者年龄和Fcgamma受体IIA基因型的影响。

BACKGROUND & AIMS: :This is the first study to explore the effect of biomaterial on tooth germ cell adhesion and proliferation in vitro. The purpose of this study is to evaluate the effects of cell-surface interactions of tooth germ cells on biomaterials with various surface hydrophilicities. The biomaterials used in this study included polyvinyl alcohol (PVA), poly(lactic-co-glycolic acid) (PLGA), poly(ethylene-co-vinyl alcohol; EVAL), and polyvinylidene fluoride (PVDF). Cell morphology was observed by photomicroscopy. Cell growth was assayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) reduction activity and the characteristic expression of amelogenin and collagen type I in tooth germ cells was investigated using immunocytochemistry. The results indicated that adhesion and proliferation of tooth germ cells to biomaterials with moderate hydrophilicity/hydrophobicity was superior compared to most hydrophobic material PVDF or mosthydrophilic material PVA in this study. Cellular adhesion and proliferation was evident on all tested biomaterials except PVA. The cell spheroids on PVA appeared not to be proliferated and remained as well as reattachable to tissue culture plates. In conclusion, biomaterials with moderate hydrophilicity are suitable for adhesion and proliferation of tooth germ cells. The material PVA may be a good biomaterial for maintaining tooth germ cells in three-dimensional biological restoration.

背景与目标： : 这是首次探索生物材料对体外牙胚细胞粘附和增殖的影响的研究。这项研究的目的是评估牙胚细胞的细胞-表面相互作用对具有各种表面亲水性的生物材料的影响。本研究中使用的生物材料包括聚乙烯醇 (PVA)，聚 (乳酸-乙醇酸) (PLGA)，聚 (乙烯-乙烯醇; EVAL) 和聚偏二氟乙烯 (PVDF)。通过显微显微镜观察细胞形态。用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基溴化四唑鎓 (MTT) 还原活性测定细胞生长，并使用免疫细胞化学研究牙胚细胞中釉原蛋白和I型胶原的特征性表达。结果表明，与大多数疏水性材料PVDF或嗜性材料PVA相比，牙胚细胞对具有中等亲水性/疏水性的生物材料的粘附和增殖要好。除PVA外，所有测试的生物材料都有明显的细胞粘附和增殖。PVA上的细胞球体似乎没有增殖，并且仍然可以重新附着到组织培养板上。总之，具有中等亲水性的生物材料适用于牙胚细胞的粘附和增殖。材料PVA可能是在三维生物修复中维持牙胚细胞的良好生物材料。

BACKGROUND & AIMS: :We employed random mutagenesis to determine the region of the initial unfolding of hyper-alkaline-sensitive subtilisin, ALP I, that precedes the denaturation of the entire protein under highly alkaline conditions. This region comprises two alpha-helices and a calcium-binding loop. Stabilization of the region caused the stabilization of the entire protein at a high alkaline pH 12. The alkaline stability of this region was most effectively improved by hydrophobic interactions, followed by ionic interactions with Arg residues. The effect of mutations on the improvement was different with regard to the alkaline stability and thermostability. This indicated that different strategies were necessary to improve the alkaline stability and thermostability of the protein.

背景与目标： : 我们采用随机诱变来确定高碱性敏感枯草杆菌蛋白酶ALP I的初始展开区域，该区域在高度碱性条件下整个蛋白质变性之前。该区域包括两个 α 螺旋和一个钙结合环。该区域的稳定导致整个蛋白质在高碱性pH 12下的稳定。通过疏水相互作用，其次是与Arg残基的离子相互作用，可以最有效地改善该区域的碱性稳定性。突变对改善的影响在碱性稳定性和热稳定性方面有所不同。这表明需要不同的策略来提高蛋白质的碱性稳定性和热稳定性。

BACKGROUND & AIMS: PURPOSE:Tear film can be altered by chronic medications that may disrupt the equilibrium responsible for the functioning of the lacrimal gland and ocular surface. The purpose of this study was to determine if antiglaucomatous chronic treatment induced alterations in the tear film and ocular surface. METHODS:After informed consent, 21 patients using antiglaucomatous eye drops for more than 8 months and 20 age- and sex-matched volunteers without eye and systemic medications (control group) were enrolled. The data of ocular discomfort, fluorescein and lisamine green staining, tear film break-up time and Schirmer test were collected and compared by Student's t test. The impression cytology data were graded and compared by chi-square test. RESULTS:Patients chronically using antiglaucomatous medications presented with significant higher fluorescein staining (p=0.003), lisamine green staining (p=0.02) and lower TFBUT (p=0.001). The other compared parameters, including impression cytology were similar between the treated and control group (p>0.05). CONCLUSIONS:The present study shows that the tear film and the ocular surface are altered in patients under antiglaucomatous medications. In common, all medications were preserved with benzalkonium chloride. Efforts to minimize the adverse effects of chronic use of antiglaucomatous drugs must be addressed.

背景与目标：

BACKGROUND & AIMS: :Sialomucins are the dominant components of the cell surfaces of some carcinoma ascites cells and have been postulated to inhibit recognition of tumours by the immune system. The sialomucin ASGP-1 (ascites sialoglycoprotein-1) of the 13762 rat mammary adenocarcinoma is associated with the cell surface as a complex with a concanavalin-A-binding glycoprotein called ASGP-2. This sialomucin complex has been purified from ascites cell microvilli by extraction with Triton X-100 and CsCl density-gradient centrifugation. ASGP-1 (which has been purified previously) and ASGP-2 were dissociated in 6 M-guanidine hydrochloride and separated by gel filtration. The molecular mass of the undenatured detergent complex of ASGP-2, estimated by gel filtration and velocity sedimentation in Triton X-100, was 148 kDa. Since the apparent molecular mass by SDS/polyacrylamide-gel electrophoresis was about 120 kDa, ASGP-2 must be a monomer as extracted from the membrane. Studies of its chemical composition indicate that it contains about 45% carbohydrate by weight, including both mannose and galactosamine. Alkaline borohydride treatment of ASGP-2 converted approx. half of the N-acetylgalactosamine to N-acetylgalactosaminitol, demonstrating the presence of O-linked oligosaccharides. Analyses of mannose-labelled Pronase glycopeptides from ASGP-2 by lectin-affinity chromatography on concanavalin A and leucocyte-agglutinating phytohaemagglutinin suggested that 40% of the label was present in high-mannose/hybrid oligosaccharides, 20% in triantennary oligosaccharides substituted on the C-2 and C-4 mannose positions and 40% in tri- or tetra-antennary oligosaccharides substituted on C-2 and C-6. The presence of polylactosamine sequences on these oligosaccharides was suggested by lectin blots and by precipitation from detergent extracts with tomato lectin. From chemical analyses and lectin-affinity studies, we estimate that ASGP-2 contains four high-mannose and 13 complex N-glycosylated oligosaccharides, plus small amounts of polylactosamine and O-linked oligosaccharides. The presence of four different classes of oligosaccharides on this glycoprotein suggests that it will be an interesting model system for biosynthetic comparisons of the different glycosylation pathways.

背景与目标： : 唾液球蛋白是某些癌腹水细胞细胞表面的主要成分，并被认为可以抑制免疫系统对肿瘤的识别。13762只大鼠乳腺腺癌的唾液酸核素ASGP-1 (腹水sialoglycoprotein-1) 与细胞表面相关，与称为ASGP-2的伴刀豆球蛋白a结合糖蛋白的复合物。通过用Triton X-100和CsCl密度梯度离心提取，从腹水细胞微绒毛中纯化了这种唾液酸苷复合物。将ASGP-1 (先前已纯化) 和ASGP-2在6 m-胍盐酸盐中解离并通过凝胶过滤分离。通过凝胶过滤和Triton X-100中的速度沉降估算，ASGP-2的未变性洗涤剂复合物的分子量为148 kDa。由于通过SDS/聚丙烯酰胺-凝胶电泳的表观分子量为约120 kDa，ASGP-2必须是从膜中提取的单体。对其化学成分的研究表明，它含有约45% 重量的碳水化合物，包括甘露糖和半乳糖胺。碱性硼氢化物处理ASGP-2转化约。N-乙酰半乳糖胺至N-乙酰半乳糖胺的一半，证明存在O-连接的寡糖。通过刀豆球蛋白A和白细胞凝集植物血凝素上的凝集素亲和色谱分析来自ASGP-2的甘露糖标记的链霉蛋白酶糖肽，表明该标记的40% 存在于高甘露糖/杂交寡糖中，在C-2和C-4甘露糖位置上取代的三天线寡糖中的20% 和在C-2和C-6上取代的三或四天线寡糖中的40%。通过凝集素印迹和番茄凝集素从洗涤剂提取物中沉淀出来，表明这些寡糖上存在聚乳糖胺序列。根据化学分析和凝集素亲和力研究，我们估计ASGP-2含有四种高甘露糖和13种复杂的N-糖基化寡糖，以及少量的聚乳糖胺和O-连接寡糖。该糖蛋白上存在四种不同类别的寡糖，这表明它将是用于不同糖基化途径的生物合成比较的有趣模型系统。

BACKGROUND & AIMS: :Internalization by cells of radiolabeled protein ligands bound to the cell surface is frequently analyzed by extraction of the cells with low pH buffers. This treatment supposedly strips the ligands from the cell surface, and remaining molecules are considered to be internalized. However, we show herein that: (1) low molecular weight catabolic products that are trapped within lysosomes (residualizing radiolabels) are efficiently extracted by low pH buffers, under the same conditions used to remove cell surface-bound material, and (2) low pH treatment lyses the majority of the cells, as shown with both a nonadherent and an adherent cell line, with the release of most of a (51)Cr label. Still, low pH extraction was effective at demonstrating Ab internalization, as has been demonstrated many times. These effects of low pH treatment may be attributed to the fixative properties of these buffers. Regardless of the mechanism, these data must be taken into consideration in interpreting the results of such experiments.

背景与目标： : 通过细胞内化结合到细胞表面的放射性标记蛋白配体经常通过用低pH缓冲液提取细胞来分析。据推测，这种处理将配体从细胞表面剥离，剩余的分子被认为是内在化的。然而，我们在本文中显示 :( 1) 在用于去除细胞表面结合材料的相同条件下，通过低pH缓冲液有效地提取了溶酶体中捕获的低分子量分解代谢产物 (残留放射性标记)，以及 (2) 低pH处理裂解大多数细胞，如非粘附细胞系和粘附细胞系所示，释放了大部分 (51)Cr标记。尽管如此，低pH萃取仍可有效证明Ab内化，正如多次证明的那样。低pH处理的这些影响可能归因于这些缓冲液的固定剂特性。无论机制如何，在解释此类实验结果时必须考虑这些数据。

BACKGROUND & AIMS: :Multi-functional bilayer polymeric coatings are prepared with both controlled nitric oxide (NO) release and surface-bound active thrombomodulin (TM) alone or in combination with immobilized heparin. The outer-layer is made of CarboSil, a commercially available copolymer of silicone rubber (SR) and polyurethane (PU). The CarboSil is either carboxylated or aminated via an allophanate reaction with a diisocyanate compound followed by a urea-forming reaction between the generated isocyanate group of the polymer and the amine group of an amino acid (glycine), an oligopeptide (triglycine) or a diamine. The carboxylated CarboSil can then be used to immobilize TM through the formation of an amide bond between the surface carboxylic acid groups and the lysine residues of TM. Aminated CarboSil can also be employed to initially couple heparin to the surface, and then the carboxylic acid groups on heparin can be further used to anchor TM. Both surface-bound TM and heparin's activity are evaluated by chromogenic assays and found to be at clinically significant levels. The underlying NO release layer is made with another commercial SR-PU copolymer (PurSil) mixed with a lipophilic NO donor (N-diazeniumdiolated dibutylhexanediamine (DBHD/N(2)O(2))). The NO release rate can be tuned by changing the thickness of top coatings, and the duration of NO release at physiologically relevant levels can be as long as 2 weeks. The combination of controlled NO release as well as immobilized active TM and heparin from/on the same polymeric surface mimics the highly thromboresistant endothelium layer. Hence, such multifunctional polymer coatings should provide more blood-compatible surfaces for biomedical devices.

背景与目标： : 多功能双层聚合物涂层是由受控的一氧化氮 (NO) 释放和表面结合的活性血栓调节蛋白 (TM) 单独或与固定化肝素组合制备的。外层由CarboSil制成，CarboSil是硅橡胶 (SR) 和聚氨酯 (PU) 的市售共聚物。CarboSil通过与二异氰酸酯化合物的脲基甲酸酯反应进行羧化或胺化，然后在聚合物的生成异氰酸酯基团与氨基酸 (甘氨酸)，寡肽 (三甘氨酸) 的胺基之间进行尿素形成反应或胺化或二胺。然后，羧化的CarboSil可以通过在TM的表面羧酸基团和赖氨酸残基之间形成酰胺键来固定TM。胺化的CarboSil也可以用于最初将肝素偶联到表面，然后可以进一步使用肝素上的羧酸基团来锚定TM。表面结合的TM和肝素的活性均通过显色试验进行评估，发现其处于临床显着水平。下面的NO释放层是用另一种市售的SR-PU共聚物 (PurSil) 与亲脂性NO供体 (N-二氮烯酸化的二丁基己二胺 (DBHD/N(2)O(2) 混合制成的。NO释放速率可以通过改变顶部涂层的厚度来调节，并且在生理相关水平上NO释放的持续时间可以长达2周。受控的NO释放以及从同一聚合物表面/在同一聚合物表面上固定的活性TM和肝素的组合模拟了高度血栓的内皮层。因此，这种多功能聚合物涂层应为生物医学设备提供更多的血液相容性表面。