28 mm Metasul™ bearings in primary total hip arthroplasty

Assessment of possible low-wear with some former metal-on-metal (MoM) total hip arthroplasties (THA) led to the reintroduction of metallic bearings in the late 80’s. The author reports on two studies of Metasul-28 mm cementless THA. In the first one in a general population, impingement has been the main cause of osteolysis and Co level survey has been a good indicator of Metasul bearing behaviour. In the second study, in a group of 83 less than 50-year-old and active patients, Metasul bearings showed good wear resistance at 7.2 years mean follow-up. In both studies, no general toxic effect could have been detected thus far. According to the current knowledge, it is always reasonable to expect low-wear and better THA longevity with use of MoM bearings under the following conditions: 1) use of a CoCr alloy with high carbide concentration; 2) reduce impingement risk (head without sleeve, slimmer as possible neck, perfectly adapted Morse cone from the same manufacturer, well — oriented components); and 3) prefer cementless acetabular fixation.     

The role of mast cells and histamine in leukocyte-endothelium interactions in four rat strains

 The objective of the present study was to determine the role of mast cells and histamine in leukocyte-endothelium interactions in mesenteric venules of four rat strains: Brown Norway, Lewis, Sprague-Dawley and Wistar. Intravital microscopy showed that the mast cell stabilizer cromoglycate (5 mg/kg i.v. just before exteriorization of the mesentery) did not affect the baseline level and velocity of leukocyte rolling in any of the four strains. This finding is in agreement with the observation that cromoglycate pretreatment only slightly influenced mast cell degranulation in all strains except the Brown Norway. After mast cell stabilization, only in Sprague-Dawley did topical administration of histamine (10^–4 M) result in a significant increase in the level of leukocyte rolling and a decrease in the rolling velocity compared with the time control. Histamine induced leukocyte adhesion only in the Brown Norway strain. In conclusion, the hypothesis presented in other studies, that degranulation of mast cells, and more specifically the release of histamine, is of major importance for the induction of leukocyte-endothelium interactions in rat mesenteric venules is not generally applicable; the present study shows a clear strain dependency. Received: 18 July 1997 / Received after revision: 17 November 1997 / Accepted: 13 March 1998     

Chemoattractant-induced firm adhesion of leukocytes to vascular endothelium in vivo is critically dependent on initial leukocyte rolling

Leukocyte rolling and firm adhesion at the venular endothelium are two discrete events in the cellular inflammatory response mediated via selectin and integrin adhesion molecules, respectively. The dependency of chemoattractant-induced firm leukocyte adhesion on the preceding rolling interaction was investigated in rat mesenteric microvessels through use of intravital microscopy. Leukocyte rolling was dose-dependently inhibited by systemic treatment with the sulphated polysaccharide fucoidin. The firm leukocyte adhesion following stimulation with the chemotactic peptide fMLP was similarly inhibited when fMLP challenge was performed subsequent to inhibition of leukocyte rolling by fucoidin. Thus, based on paired observations in single venules before and after fucoidin treatment, reduced rolling leukocyte flux prior to fMLP challenge was paralleled over a wide range by a proportional decrease in fMLP-induced leukocyte adhesion. The results demonstrate quantitatively a close relationship between the extent of leukocyte rolling and the magnitude of the subsequent firm adhesion response, and, that an initial rolling interaction is a precondition for firm adhesion to occur at physiological blood flow rates in vivo.     

A protease inhibitor attenuates gastric erosions and microcirculatory disturbance in the early period after thermal injury in rats

The effects of camostat mesilate, a synthetic serine protease inhibitor on gastric microcirculation and active oxygen species generated by leucocytes from the gastric and jugular veins in the early period after thermal injury were assessed. Male Wistar rats were anaesthetized and a 30% full skin-thickness dorsal burn was inflicted. Camostat mesilate (100 mg/kg) was dissolved in distilled water and administered orally to rats 40 min before thermal injury (the camostat group). The control animals (the vehicle group) were administered distilled water orally. Rolling leucocytes as well as Monastral blue B deposits in venules were observed using in vivo microscopy. Active oxygen species were measured by chemiluminescence. Camostat mesilate decreased the total length of gastric erosion, venular deposits of Monastral blue B, and rolling of leucocytes in venules, and relatively increased luminol-dependent chemiluminescence activity generated by zymosan-stimulated leucocytes 15 min after thermal injury. These results suggest that serine proteases are involved in the formation of gastric erosions and gastric microcirculatory disturbance in the early period after thermal injury.     

关于中医推拿手法摆动类法施力的频域分析

依据中医推拿手法测力分析仪ＦＺ－Ⅰ型上所测得的施力数据，对各向作用力进行频域分析，并对各频段成分在综合推拿效用中所起的作用以及与其它因素的相互关系作了比较与分析。     

小鼠腭板旋转培养模型的建立及其初步应用

目的为研究全反式视黄酸(atRA)对小鼠腭板发育的影响及其致腭裂的机制,建立腭板旋转培养模型。方法于妊娠第12天取下小鼠胚胎腭移植体,以10-5～10-1μmolLatRA诱导,在旋转培养装置中连续培养72h,观察腭板发育融合情况。结果经72h培养后,对照组正常融合,与体内发育一致。atRA在10-5μmolL能促进腭板的融合,≥10-4μmolL抑制腭板的发育及融合,造成腭裂,融合率下降,并呈显著的剂量-效应关系。结论本模型中,腭板能在体外培养中存活并继续生长、发育、融合;atRA在10-5μmolL能促进腭板融合,高于10-4μmolL呈剂量-效应关系的抑制融合,造成腭裂,证明小鼠腭板旋转培养模型建立成功。     

The reliability of modern alumina bearings in total hip arthroplasty—Update to a 2006 report

Ceramic components׳ clinical fractures in total hip arthroplasty (THA) are a rare but, nonetheless, serious complication. As a result of continued improvements in ceramic material quality, manufacturing methods, and implant design made over the last 30 years, the incidence of such failures has been drastically reduced. In this report, the frequency of these ceramic components׳ clinical failures in THA will be examined. In addition, some information regarding the contribution that can be made by the surgeon to enhance the reliability of ceramic components will also be presented. In order to get a broad view, the largest supplier of these components, CeramTec Medical Products (Plochingen, Germany), was contacted, and they agreed to share their most recent data. In the year 2000, the largest supplier of alumina–ceramic bearings for orthopedic applications (CeramTec GmbH, Plochingen, Germany) began a rigorous program of collecting clinical fracture data for all of its ceramic components. The clinical fracture data for the period of January 2000–June 2013 are reported here, with a review of the material properties, historical component fracture trends, and relative risk of fracture associated with alumina THA bearings. The data reported is divided into two separate groups. The first one is the incidence of clinical fracture of the Biolox^® forte material. This is their original material developed in the 1970s and is still available today and optimized over the years. The overall clinical fracture rate of these alumina components was 0.021%, or 21 in 100,000, during the January 2000–June 2013 time period. The second group is composed of components manufactured from their Alumina Matrix Composite, Biolox^® delta. The overall clinical fracture rate for these components is 0.0001% or 1 in 100,000. Almost 80% of these alumina bearing failures occurred within 36 months following surgery. Using the latest material and increasing femoral head diameter were associated with a substantially reduced risk of fracture. Alumina bearings used in modern THA implants are safe and reliable, with a very low risk of failure. Improvements in the materials, developments in the manufacturing, the introduction of the Alumina Matrix Composite, and the trend to utilize larger-diameter ball heads are likely to continue to reduce the concerns that have been in the mind of surgeons using ceramics in THA.     

Fundamental Improvement of Creep Resistance of New-Generation Nano-Oxide Strengthened Alloys via Hot Rotary Swaging Consolidation

New-generation oxide dispersion-strengthened (ODS) alloys with a high volume fraction of nano-oxides of 5% are intended to become the leading creep- and oxidation-resistant alloys for applications at 1100–1300 °C. Hot consolidation of mechanically alloyed powders by intensive plastic deformation followed by heat treatment of the alloys are the key aspects for achieving top creep properties, typically ensured by a coarse-grained microstructure strengthened with homogeneously dispersed, very stable yttrium nano-oxides. The rotary swaging method proves to be favourable for hot consolidation of the new-generation ODS alloy presented. Compared to specimens consolidated by hot rolling, consolidation by hot rotary swaging predetermines the formation of coarse grains with a very high aspect ratio during subsequent secondary recrystallization. Such a grain morphology increases the creep strength of the new-generation ODS alloy considerably.     

PSGL‐1 and E/P‐selectins are essential for T‐cell rolling in inflamed CNS microvessels but dispensable for initiation of EAE

T‐cell migration across the blood‐brain barrier is a crucial step in the pathogenesis of EAE, an animal model for MS. Live cell imaging studies demonstrated that P‐selectin glycoprotein ligand‐1 (PSGL‐1) and its endothelial ligands E‐ and P‐selectin mediate the initial rolling of T cells in brain vessels during EAE. As functional absence of PSGL‐1 or E/P‐selectins does not result in ameliorated EAE, we speculated that T‐cell entry into the spinal cord is independent of PSGL‐1 and E/P‐selectin. Performing intravital microscopy, we observed the interaction of WT or PSGL‐1^?/? proteolipid protein‐specific T cells in inflamed spinal cord microvessels of WT or E/P‐selectin^?/? SJL/J mice during EAE. T‐cell rolling but not T‐cell capture was completely abrogated in the absence of either PSGL‐1 or E‐ and P‐selectin, resulting in a significantly reduced number of T cells able to firmly adhere in the inflamed spinal cord microvessels, but did not lead to reduced T‐cell invasion into the CNS parenchyma. Thus, PSGL‐1 interaction with E/P‐selectin is essential for T‐cell rolling in inflamed spinal cord microvessels during EAE. Taken together with previous observations, our findings show that T‐cell rolling is not required for successful T‐cell entry into the CNS and initiation of EAE.