国人跟骨距关节面的形态研究

观察329块(男193,女136)国人成年跟骨的距关节面形态。其中A型出现率,男为45.08±3.58％,女为41.18±4.22％;B型出现率男为53.89±3.59％,女为58.82±4.22％;C型仅男性出现2例,占1.04±0.73％。成套标本中,距关节面左右对称的,男性90例中有81例,占90.00±3.16％;女性67例中有59例,占88.06±3.96％。经统计学处理,侧别间及性别间均无明显差异。文内结合观察结果提出自己的分型标准及类型,并与以往资料进行了比较。     

Topical application of fluorides on teeth

Abstract Prevention of caries in exposed root surfaces constitutes an important clinical problem. It is thus important that clinicians involved with periodontology have an insight into fluoride prophylaxis. The understanding of the cariostatic mechanism of fluoride has improved during recent years. The aim of the present review is to give a short account of the present concept. Calcium fluoride appears to be the only product which is formed on enamel, dentin or cementum during brief topical treatments with fluoride or use of toothpaste containing fluoride. This calcium fluoride is stable in the oral environment: this is contrary to what was believed until recently. The calcium fluoride constitutes a pH-dependant reservoir of fluoride which releases fluoride when pH drops. The practical consequences of this concept is discussed.     

Synaptosomal Na, K-ATPase during forebrain ischemia in Mongolian gerbils

We studied the activity and kinetic parameters of synaptosomal Na, K-ATPase during 15 min of forebrain ischemia and following 60 min of reperfusion produced by reversible common carotid occlusion in Mongolian gerbils. A synaptosomal fraction was obtained by both differential centrifugation of brain tissue homogenate and centrifugation of crude mitochondrial fraction at a discontinual sucrose density gradient. We found two components of ATP concentration dependence of ATP hydrolysis that represent two types of ATP-binding sites: high affinity and low affinity. Neither ischemia nor reperfusion affected kinetic parameters of a high-affinity site. However, lowaffinity site parameters were affected by both ischemia and ischemia followed by reperfusion. Maximal velocity (V _max) decreased by 43 and 42% after ischemia and after ischemia/reperfusion, respectively. The apparentK _m for ATP decreased by 52% after ischemia and by 47% after ischemia/reperfusion. The apparent affinities for K⁺ and Na⁺ were determined from the ATP hydrolysis rate as a function of Na⁺ and K⁺ concentrations. We found the half-maximal activation constant for K⁺ (K _a K⁺) increased by 60% after ischemia and by 146% after ischemia/reperfusion. On the other hand, we found thatK _aNa⁺ decreased significantly after ischemia/reperfusion (16%). We concluded that it is the dephosphorylation step of the ATPase reation cycle that is primarily affected by both ischemia and ischemia/reperfusion. This might be caused by alteration of the protein molecule and/or its surroundings subsequent to ischemia.     

Reversible Adsorption of Soluble Hexameric Insulin onto the Surface of Insulin Crystals Cocrystallized with Protamine: An Electrostatic Interaction

Mixing pharmaceutical preparations of soluble neutral regular insulin solution (NRI) and neutral protamine Hagedorn (NPH) crystalline insulin suspension leads to a reduction in the measurable amount of soluble insulin in the formulation supernatant. However in spite of the loss in soluble insulin, the time-actions of these components have been shown, in clinical trials, to be unaffected. The interaction between these different physical forms of insulin has been studied using reversed-phase HPLC, isothermal titrating calorimetry, and Doppler electrophoretic light scattering analysis. Sorbent surface and solution perturbation studies revealed that the NRI adsorbs to the surface of the NPH crystal with an equilibrium constant ranging from 10⁴ M^–1 to 10⁷ M^–!, depending on the protamine concentration, pH, ionic strength, and temperature. This adsorption behavior suggests that the binding is mediated by electrostatic interactions arising between the positively-charged NPH crystal and the negatively-charged NRI hexamer. Doppler electrophoretic light scattering results, used to probe the pH-dependent surface charge of NPH and soluble insulin hexamer, support the conclusion that electrostatic interactions mediate the adsorption process. Adsorption studies under physiological conditions indicate that the elevated temperature and ionic strength, in a subcutaneous depot, are sufficient to lead to the dissociation of the NRI/NPH complex that exists in these NPH mixture formulations.     

曲马多作为喉部表面麻醉辅助药的效果观察

实验观察曲马多对小鼠中枢情绪反应和电刺激豚鼠引起咽反射的影响，８０只小鼠和４０只豚鼠分成四组．表面麻醉前各组小鼠分别注射东莨菪碱：东莨菪碱加曲马多：阿托品：阿托品加曲马多。结果表明，曲马多能明显增加小鼠激怒情绪反应的电刺激次数和提高电刺激豚鼠咽反射的电压阈值（Ｐ＜０．０１）并能显著加强东莨菪碱对中枢的镇静作用和降低呵托品对中枢的兴奋作用。临床上观察１６０例声带息肉手术患者，分四组，表面麻醉前给药方法如上。结果表明，曲马多作辅助用药时，既可减少丁卡因用量，又可缩短手术时间，还可降低患者的不适和疼痛。     

单克隆抗体对溶组织内阿米巴吞噬红细胞的影响

用具有抗细胞膜活性和抗细胞核、胞浆活性的单克隆抗体３Ｆ７和４Ｇ６与致病性溶组织内阿米巴ＨＭ－１∶ＩＭＳＳ株滋养体３７℃孵育，在孵育即刻、５ｍｉｎ、１０ｍｉｎ加入红细胞，检测滋养体吞噬红细胞的能力，并以正常小鼠血清和抗克氏锥虫抗体ＴＣＥ０４作为对照。结果，经单克隆抗体３Ｆ７孵育即刻的ＨＭ－１∶ＩＭＳＳ虫株滋养体吞噬红细胞能力明显减弱（Ｐ＜０．００１），而４Ｇ６抑制滋养体吞噬红细胞的作用不如前者明显。提示，抗细胞膜单克隆抗体对抑制滋养体吞噬红细胞有显著作用，但随着时间的推移，抑制作用明显减弱。     

Active surfactant in pharyngeal aspirates of term neonates: lipid biochemistry and surface tension function

Alveolar surfactant is well known for its ability to reduce minimal surface tension at the alveolar air–liquid interface to values below 5 mN m^?1. In addition, it has been suggested that surfactant is also present in the airways, particularly in the perinatal period. We isolated surfactant from pharyngeal aspirates obtained from 33 neonates immediately after delivery and analysed it for both phospholipid (PL) composition and surface tension function. PL classes and phosphatidylcholine (PC) molecular species were determined by normal and reversed-phase high-performance liquid chromatography (HPLC), respectively. Static and dynamic surface properties of the surfactant were studied in a pulsating bubble surfactometer. Sample volume was 1.3 ± 0.5 mL (mean ± SD) with a total amount of 2.5 ± 1.3 μmol of PL and a concentration of 2.1 ± 1.0 μmol mL^?1 PL. HPLC analyses of PL classes revealed a composition identical with surfactant prepared from alveolar washes, i.e. PC 83.6 ± 2.1%, sphingomyelin 1.4 ± 0.5%, phosphatidylglycerol 8.1 ± 1.6%, phosphatidylethanolamine 2.1 ± 0.5% and phosphatidylinositol 2.6 ± 1.1%. Thin-layer chromatography showed almost identical results but was more time-consuming and needed more material for analysis. Analysis of PC molecular species revealed a composition typical of human alveolar surfactant with 54.7 ± 3.9% dipalmitoyl PC, 10.3 ± 1.9% palmitoyloleoyl PC and 9.1 ± 1.5% palmitoylmyristoyl PC. Minimal surface tension fell to values below 5 mN m^?1 within 5 min of cycling in all subjects. The methods used in this study allowed for complete PL and surface tension analyses of surfactant obtained during routine pharyngeal suctioning after delivery at term. Whether they are also applicable to preterm neonates with respiratory distress remains to be determined.     

Surface-related triggering of the neutrophil respiratory burst. Characterization of the response induced by IgG adsorbed to hydrophilic and hydrophobic glass surfaces

Hydrophilic and hydrophobic glass surfaces precoated with human albumin, fibrinogen, or IgG were investigated with respect to their ability to activate the neutrophil NADPH-oxidase. We found that IgG-coated surfaces induced a substantial and prolonged neutrophil production of reactive oxygen species (ROS). When a hydrophilic surface was used to support protein binding, a somewhat lower neutrophil response (around 35%) was obtained, compared with the response induced by IgG on a hydrophobic surface. The production of ROS was completely eliminated when cytochalasin B was added to the measuring system, suggesting the involvement of the cell cytoskeleton in the activation process. The relation between the intra- and extracellular generation of ROS was further assessed, and we found that most of the ROS produced were released from the cells, in agreement with a model in which the activating surfaces induce a ‘frustrated’ phagocytic response. Serum totally inhibited ‘frustrated’ phagocytosis provided that the IgG molecules were sticking to a hydrophilic surface.     

Motor unit potential contribution to surface electromyography

The background of the bioelectric activity of muscle recorded from the surface of the skin (surface electromyography) in terms of the representation of single motor units of the underlying muscle(s) is not very well documented or understood. An insight into the composition of an electromyogram is essential for the proper interpretation of one of the most widely applied electrophysiological techniques. In the present paper, a study of the contribution of single motor unit potentials to the surface electromyogram is presented. To this end, the decline of different components of the motor unit potential with depth of the motor unit is quantified. Experimentally, the action potentials from motor units at several positions in the muscle were recorded by 30 skin surface electrodes. Simultaneous use of scanning electromyography provided information about the actual position and size of the motor unit. Observed linear log–log relationships between motor unit potential magnitudes and distance indicated the usefulness of a power function to describe the motor unit potential's dependence on recording distance. It is shown that different specific surface motor unit potential characteristics fall off differently with depth. The magnitude–distance relationship is shown to be dependent on the recording configuration (unipolar vs. bipolar recording, including the inter-electrode distance) and the chosen motor unit potential parameter (negative peak amplitude, positive peak amplitude and area).     

脉冲激光射线强化金属材料的几个问题

本文讨论了激光脉冲射线强化金属材料的几个问题:强化图形,材料性能,加工用量及表面涂层对被强化表面性能的影响。