关于国人成年男子(活体)睾丸大小的调查

本文报道了对3069例健康成年人的睾丸进行了测量,大多数正常成年人双侧睾丸长、宽、厚是相等的。随着年龄的增长,睾丸有逐渐变小的趋势。如双侧睾丸大小相差明显,多是由泌尿生殖系疾病所致。     

抗菌素保存乳牙活髓87例分析

临床上乳牙龋病的治疗通常不强调牙髓活力的保存.但乳牙失去活力后往往造成乳牙根的过早吸收,从而引起乳牙的早失.笔者采用抗生素治疗乳牙龋,意在保存乳牙牙髓的活力.结果表明:选用抗菌力强、毒性反应低、刺激性小的广谱抗菌素对乳牙龋病的治疗及对牙髓活力的保存有明显疗效.     

Temporal profile of forced expiratory lung function in allergen-challenged Brown-Norway rats

The Brown–Norway rat is often used to study the allergic pulmonary response. However, relatively little is known about the delayed phase reactions after allergen challenge in this species. To evaluate the temporal changes in lung function and elucidate the mechanisms involved in the delayed phase response, Brown–Norway rats were sensitized and challenged to aerosolized ovalbumin and lung functions were measured by forced expiratory maneuvers and forced oscillation for up to 10 days after a single antigen challenge. Statistically significant (P < 0.05) reductions in inspiratory capacity, forced vital capacity, functional residual capacity, peak expiratory flow and maximum mid-expiratory flow and increases in respiratory system resistance and elastance were seen by 1 to 3 days after ovalbumin challenge that returned to baseline by 10 days. The reductions in lung function after ovalbumin challenge were blocked by the corticosteroid, betamethasone (1 mg/kg, p.o.). Histological evaluation of lung tissue of sensitized rats demonstrated evidence of interstitial pulmonary edema, an increase in tissue eosinophils and an increase in Periodic Acid Schiff-positive cells in the airway epithelium. Bronchoalveolar lavage fluid samples showed large numbers of eosinophils and increased mucin content up to 6 days after antigen challenge. There was also an increase in wet-to-dry lung weight ratio in the lungs of sensitized rats after antigen. These results demonstrate that prolonged reductions in lung function occur after a single antigen challenge in Brown–Norway rats that is probably due to inflammatory processes producing interstitial pulmonary edema, mucus secretion and cellular influx into the lungs.     

长春市城区医学人口统计

长春市人口已从1949年的475,403人增长到1983年的1,771,170人,增长了2.7倍,平均年增长率为38.3‰。人口的年龄结构:50年代为增加型,80年代逐渐趋向稳定型。人口金字塔:80年代塔基明显缩小。普通死亡率逐年下降。50年代死亡率为15.7‰,80年代为4.53‰。年龄死亡构成发生明显变化,80年代50岁以上死亡者占死亡总数的85％以上,婴幼儿死亡比例明显减少。我市死因顺位发生明显改变,80年代依次心脏病、脑血管病、恶性肿瘤和意外死亡为前四位死因。平均期望寿命延长,81～83年男性为72.82岁,女性为74.38岁。现在我市人民健康水平已接近发达国家水平。     

The effect of extracellular calcium concentration and Ca-antagonist drugs on enzyme release and lactate production by anoxic heart cell cultures

Tissue cultures of neonate rat heart cells were subjected to anoxia for 16 h in the presence of 5 mm glucose and increasing concentrations of calcium in the incubation medium. When the calcium content of the culture medium was increased, release of intracellular enzyme was observed. Increased extracellular calcium concentration appeared to have no effect on normoxic tissue preparations. The time course of this anoxia-related change was examined. Increasing the calcium concentration of the medium caused an acceleration of the anoxia-induced rate of enzyme leakage when compared with anoxic cultures exposed to a low medium calicum concentration. The calcium-induced increase in anoxic enzyme release could be partially reversed by various concentrations of the calcium antagonist drugs verapamil and nifedipine. Verapamil and nifedipine both appear to reduce the extent to which an elevated medium calcium concentration is able to reduce myocyte ATP content under anoxic conditions. These drugs appear to be without effect on ATP content of anoxic cells exposed to a low calcium concentration on the medium. Calcium-induced increases in enzyme leakage cannot be modified by the provision of high medium glucose concentrations, and hypertonic solutions of mannitol exacerbate damage to myocytes under anoxic and hypercalcaemic conditions. These data suggest that high extracellular concentrations of calcium exacerbate damage to heart cells subjected to anoxia although the mechanism underlying this exacerbation is uncertain.     

四川省2003年孕产妇死亡潜在损失分析

目的探讨孕产妇主要死亡原因及其所造成的潜在寿命、工作、价值损失情况。方法通过四川省2003年孕产妇死亡监测网收集死亡及存活产妇数,计算孕产妇死亡所造成的潜在寿命损失年数、平均减寿年数、潜在工作损失年数、潜在价值损失年数。结果2003年全省孕产妇死亡93例,潜在寿命损失年数为4016人年,平均减寿年数为43人年,潜在工作损失年数为2305人年,潜在价值损失年数为2608人年。结论孕产妇死亡年龄较轻,造成潜在损失重大,不仅危害了妇女的生命,而且对社会和经济造成了重大损失。     

基于FPGA的超声射频信号自适应滤波器

目的 医学超声的射频回波信号具有明显的时变特性,传统滤波器难以获得理想的滤波效果,本文提出一种基于现场可编程门阵列（field programmable gate array,FPGA）的实时自适应滤波器以解决这一问题.方法 根据双通道自适应滤波器原理,设计双脉冲激励以获得双通道输入,滤波器集成在一个Altera Cyclone II FPGA上,采用延时最小均方误差（delayed least-mean-square,DLMS）控制算法以提高速度.结果 对超声体模和人体组织回波进行的仿真及硬件滤波实验表明,该滤波器具有明显的信号增强作用,对不同深度信号的处理效果没有明显的差别,并且可以达到50MS/s的数据吞吐量,满足实时处理要求.结论 FPGA速度快,体积小,耗电低,在超声扫描仪中应用广泛,本文提出的基于FPGA超声射频信号的自适应滤波方案滤波效果明显,具有很强的实用性.     

Molecular dynamics calculations suggest a conduction mechanism for the M2 proton channel from influenza A virus

The M2 protein of the influenza A virus is activated by low endosomal pH and performs the essential function of proton transfer into the viral interior. The resulting decrease in pH within the virion is essential for the uncoating and further replication of the viral genetic material. The x-ray crystal [Stouffer AL, et al. (2008) Nature 451:596–599] and solution NMR [Schnell JR, Chou JJ (2008) Nature 451:591–595] structures of the transmembrane region of the M2 homo-tetrameric bundle both revealed pores with narrow constrictions at one end, leaving a question as to how protons enter the channel. His-37, which is essential for proton-gating and selective conduction of protons, lies in the pore of the crystallographic and NMR structures. Here, we explore the different protonation states of the His-37 residues of the M2 bundle in a bilayer using molecular dynamics (MD) simulations. When the His-37 residues are neutral, the protein prefers an Open_out-Closed_in conformation in which the channel is open to the environment on the outside of the virus but closed to the interior environment of the virus. Diffusion of protons into the channel from the outside of the virus and protonation of His-37 residues in the tetramer stabilizes an oppositely gated Closed_out-Open_in conformation. Thus, protons might be conducted through a transporter-like mechanism, in which the protein alternates between Open_out-Closed_in and Closed_out-Open_in conformations, and His-37 is protonated/deprotonated during each turnover. The transporter-like mechanism is consistent with the known properties of the M2 bundle, including its relatively low rate of proton flux and its strong rectifying behavior.     

脱敏剂防治活髓基牙预备后牙本质敏感的观察

目的：探讨＂劲润＂牙本质保护膜对固定义齿活髓基牙预备后牙本质过敏症的防治效果。方法：将64例（共142颗基牙）进行固定修复治疗的患者随机分为试验组、对照组,试验组用＂劲润＂牙本质保护膜处理牙齿预备表面,对照组采用30%草酸钾饱和溶液处理牙齿预备面。所有基牙均采用暂时冠修复。7～10d后试戴修复体时,观察治疗效果,并进行统计学分析。结果：经脱敏剂处理过的基牙过敏症状均有明显改善。试验组和对照组的差异无统计学意义（P〉0.05）。结论：＂劲润＂牙本质保护膜可以有效预防全冠活髓基牙预备后牙本质过敏症的发生,值得在临床上推广使用。