Decreased platelet function in Cavalier King Charles Spaniels with mitral valve regurgitation

With aggregometry, increased platelet activity has been reported in Cavalier King Charles Spaniels (CKCS) without mitral regurgitation (MR). In contrast, dogs with MR have been found to have decreased platelet activity. The purpose of this study was to test an easy bedside test of platelet function (the Platelet Function Analyzer [PFA-100]) to see if it could detect an increase in platelet activity in CKCS without MR and a decrease in platelet activity in CKCS with MR. This study included 101 clinically healthy dogs > 1 year of age: 15 control dogs of different breeds and 86 CKCS. None of the dogs received medication or had a history of bleeding. The PFA-100 evaluates platelet function in anticoagulated whole blood under high shear stress. Results are given as closure times (CT): the time it takes before a platelet plug occludes a hole in a membrane coated by agonists. The CT with collagen and adenosine-diphosphate as agonists was similar in control dogs (median 62 seconds; interquartile interval 55-66 seconds) and CKCS with no or minimal MR (55; 52-64 seconds). The CT was higher in CKCS with mild MR (regurgitant jet occupying 15-50% of the left atrial area) (75; 60-84 seconds; P = .0007) and in CKCS with moderate to severe MR (jet > 50%) (87: 66-102 seconds; P < .0001). CKCS with mild, moderate, and severe, clinically inapparent MR have decreased platelet function. The previous finding of increased platelet reactivity in nonthrombocytopenic CKCS without MR could not be reproduced with the PFA-100 device.     

哺乳动物附植前胚胎的基因表达调控

哺乳动物胚胎附植前期包括:合子的形成,胚胎基因组的激活和细胞分化的开始。在这个时期,发育由母源物质控制转为合子基因控制,在此过程,同时形成染色质介导的转录抑制时期,要解除抑制必须经过胚胎基因组的激活。通过对体内、外附植前胚胎的mRNA的表达特点以及它们与成功发育联系的研究,可以筛选出最佳的体外培养条件,设计最佳的核移植方案。     

Dual-chamber pacemaker implantation via the cephalic vein in healthy equids

The purpose of the present study was to develop a feasible and safe technique for dual-chamber pacemaker implantation in healthy horses. Implantation was performed in a standing, tranquilized horse and in ponies. Atrial and ventricular leads were transvenously inserted through the cephalic vein, and a subcutaneous pacemaker pocket was created between the lateral pectoral groove and the manubrium sterni in 6 equids. Positioning of each lead was guided by echocardiography and by measuring the electrical characteristics of the lead. The implantation procedure lasted about 4 hours in each animal and was well tolerated. In all animals, dual-chamber pacemaker function was obtained, and these results remained good throughout the follow-up period. At the time of implantation, atrial and ventricular sensing were between 2.1 and 7.2 mV and 7.8 and 16.8 mV, respectively, and atrial and ventricular pacing thresholds at 0.5 millisecond varied from 0.5 to 0.7 V and from 0.3 to 1.0 V, respectively. Six months after the implantation, sensing values varied from 2 to 10 mV for the atrial lead and from 2 to 16 mV for the ventricular lead, while pacing thresholds at 0.5 millisecond varied from less than 0.5 to 2.5 V for the right atrium and from less than 0.5 to 5.0 V for the right ventricle. Atrial lead dislodgment occurred in 2 animals, requiring insertion of a new lead. Ventricular lead dislodgment was not observed.     

牛、羊卵母细胞孤雌激活的研究

本试验主要比较了离子霉素、电脉冲两种方法激活牛、羊体外成熟卵母细胞的效率。两种激活方法中。牛胚胎卵裂率无显著差异（90．61％对94．40％，P〉0．05），而离子霉素激活胚胎的囊胚发育率极显著高于电激活方法（12．3％对2．4％，P〈0．01）。两种方法对羊胚胎的研究中，羊胚胎卵裂率无显著差异（72．4％对77．4％，P〉0．05）。但是离子霉素激活胚胎的囊胚发育率显著高于电激活方法（3．67％对10．40％，P〈0．05）。本试验中还比较了用化学激活法（离子霉素）激活牛体外成熟卵母细胞后，用SOFaa体系培养，换液与不换液对孤雌激活胚胎体外发育的影响。结果表明：在第4天不换液的胚胎卵裂率和囊胚率极显著高于换液的胚胎（11．64％对3．49％。P〈0．01）。     

序贯培养法对猪孤雌激活胚胎发育能力的影响

经体外成熟、孤雌激活和培养获得猪胚胎,研究了不同培养体系、共培养体细胞和序贯培养对猪孤雌激活胚胎发育的影响。试验表明:孤雌激活卵母细胞在SOF 10?S培养体系中分裂效果最好,添加胎牛血清的NCSU-23和颗粒细胞对胚胎发育有促进作用,培养6d后发育到桑囊胚的比率增加(P<0.05)。在序贯培养的前3d,SOF培养基(不含葡萄糖)和颗粒细胞对胚胎的发育有促进作用,分裂率(P<0.05)和突破4细胞阻滞的数目显著增加,在培养的后3d,添加胎牛血清的NCSU-23和输卵管上皮细胞能支持较多胚胎发育到桑囊胚,桑囊胚的发育率为(59.5±3.2)%(P<0.05)。结果表明,SOF培养基和颗粒细胞 添加胎牛血清的NCSU-23和输卵管上皮细胞的序贯培养系统能较好的促进胚胎的发育。     

Physical activation of biochar and its meaning for soil fertility and nutrient leaching – a greenhouse experiment

The slow alteration of the surface of charred biomass (biochar) over time may contribute to an improved nutrient retention and thus fertility of tropical soils. Here, we investigated soils from temperate climates and investigated whether a technical steam activation of biochar could accelerate its positive effects on nutrient retention and uptake by plants relative to nonactivated biochar. To this aim, we performed microcosm experiments with sandy or silty soil, mixed with 2.0, 7.5 and 15.0 g/kg soil of fine (<2 mm) or coarse‐sized (2–10 mm) biochar from beech wood (Fagus sp.). After initial fertilizer (NPK), ashes and excess nutrients were leached with water, and the microcosms were planted for 142 days with Italian Ryegrass (Lolium multiflorum ssp. italicum). Thereafter, leachate, soil and plant samples were analysed for their nutrient contents. The results showed that biochar additions of ≤15 g/kg soil left elevated contents of available P and N in the surface soil but reduced their uptake into the plants. As a result, total biomass production was unchanged. Different particle size and application amounts influenced these findings only marginally. Nitrate leaching was enhanced in the sandy soil (+41% for nitrate, but reduced in the silty soil ?17%) and P was immobilized. Hence, the fertility of the temperate soils under study was only marginally affected by pure biochar amendments. Steam activation, however, almost doubled the positive effects of biochars in all instances, thus being an interesting option for future biochar applications.     

铅酸蓄电池复合脉冲活化原理及电路设计

分析铅酸蓄电池充、放电化学反应过程及其硫化现象、原因和危害,探讨解决硫化问题的途径和主要方法,研究铅酸蓄电池脉冲充电的活化原理,设计了一种复合脉冲循环充放电工作电路.为铅酸蓄电池活化与修复研究提出了新的观点和应用技术.     

桑蚕卵电晕人工孵化技术研究：V.电晕处理蚕种的农村饲育

通过１９９４～１９９６年电晕处理蚕种的农村饲养，得到以下几点认识，在保证卵面消毒和排除孵化不齐因素情况下，电晕蚕种与浸酸蚕种的产量质量无显著差异，专供农用的大板电晕仪存在放电不匀，孵经不齐和孵化率欠高的问题，有待改进，电晕处理蚕种还须进行卵消毒。     

健康黑松幼苗中的电波传递

以健康黑松(Pinus thunbergii)幼苗为材料,用非伤害性刺激,如冷冻和伤害性刺激,如：烧伤、刺伤、化学伤害等引发了植物体内的波形的变化,研究表明,非伤害性刺激能在幼苗体内引起动作电波的传递,伤害性刺激除了能引起动作电波的传递外,还能引起较为复杂的变异电波的传递并对这种现象进行了讨论。图4参28。     

The Ionic and Osmotic Factors Controlling Motility of Fish Spermatozoa

This review presents actual knowledge about energetic, ionic, osmotic and gaseous control of fish sperm motility and its duration. Right after they are activated, fish spermatozoa of most species swim for a short period of time, in the range of one to several minutes. What determines the activation process? Is it due to the new ionic, gaseous and/or osmotic environment? Why is the duration of motility so short? Is it resulting from a fast exhaustion of energy stores (ATP, ADP, AMP, PCr) combined with the above-mentioned ionic/osmotic stress leading to morphological alterations? The motility criteria (flagellar beat frequency, head displacement velocity, flagellar waves morphology, etc.) used to characterize fish sperm movement and sperm flagella will be described. Most parameters change very rapidly during the brief motility period of fish sperm. Then will be considered the main environmental factors, ionic and/or osmotic signals, responsible of the activation of fish sperm motility. Then the metabolic compounds involved in cell energetics will be considered as their concentrations also rapidly change during the motility phase. An additional feature will then be discussed concerning the mechanisms by which fish sperm cell can be revived for a second motility round at the end of the first motility period. A model is proposed to explain how external osmolarity can control internal ionic composition, the latter being the key factor controlling flagellar activity.