Effects of accessory sex gland fluid on viability, capacitation, and the acrosome reaction of cauda epididymal bull spermatozoa

The effect of accessory sex gland fluid (AGF) on viability and acrosomal integrity of spermatozoa was examined with cauda epididymal spermatozoa and AGF from the same Holstein bull (n = 6). Surgical cannulation of the vasa deferentia enabled the separate collection of cauda epididymal effluent and AGF from each bull. Cauda epididymal effluent was incubated with either AGF collected from the same bull or medium alone. Following coincubation, spermatozoa (5 x 10(7) sperm/mL) were incubated in medium alone or under capacitating conditions (10 microg/mL heparin) for 16 hours. Every 2 hours, an aliquot of spermatozoa was exposed to lysophosphatidylcholine (100 microg/mL) to induce the acrosome reaction in capacitated spermatozoa. Sperm motility decreased over time regardless of treatment. Overall, spermatozoa incubated in AGF had fewer acrosome-intact live spermatozoa than did those not incubated in AGF. Viability was significantly (P < .05) compromised over time when spermatozoa were exposed to AGF, compared with those not preincubated in AGF. Significantly more (P < .05) acrosome-reacted live spermatozoa were seen following exposure to heparin and lysophosphatidylcholine when spermatozoa were not preincubated in AGF. We conclude that exposure of spermatozoa to AGF accelerates cell death and that rapid removal of spermatozoa from seminal plasma is critical for maximal viability.     

单克隆抗体博来霉素A6偶联物对白血病细胞特异性结合与内化

抗CCT2单克隆抗体博来霉素A6偶联物可吸附胶体金颗粒(McAb-A6-Au)。电镜观察表明,在4℃,1h,表面有McAb-A6-Au颗粒的CEM细胞最高达78%;在37℃,4h,内化McAb-A6-Au颗粒的CEM细胞高达72%。而抗原性无关的U937细胞仅为14%。并且McAb-A6-Au颗粒能直接穿过细胞膜、核膜进入细胞浆和细胞核。37℃,1h已有10～18%的CEM细胞核内有McAb-A 6-Au颗粒。实验结果提示了单抗与博来霉素A6的偶联物与选择性地结合靶细胞,而且进入细胞速度快、穿透力强,有可能成为治疗白血病药物。     

Effects on the buoyant density of rabbit platelets of ADP and agents that increase the concentration of cyclic AMP

Rabbit platelets were aggregated by adenosine diphosphate (ADP), allowed to deaggregate and then separated into density subpopulations by centrifugation through discontinuous Stractan density gradients. Although ADP causes little or no release of the contents of the amine storage granules of rabbit platelets, ADP caused a decrease in platelet density as compared with control platelets subjected to the same procedures except for exposure to ADP. The density change persisted for at least four hours. The apparent size of platelets stimulated with ADP increased initially, but returned to control values during a one-hour period. A similar decrease in platelet density was observed with an albumin density gradient. Under conditions in which aggregation did not occur in response to ADP with ethylenediaminetetraacetic acid (EDTA) in the medium, little or no decrease in platelet density was observed. Agglutination with polylysine did not change platelet density. Thus, not only agents such as thrombin and plasmin that cause the release of the contents of the platelet granules decrease platelet density, but ADP also has this effect. Platelets would be exposed to all of these stimuli during thromboembolic processes, and their effect on platelets may account for the decrease in platelet density observed previously in experiments with rabbits with indwelling aortic catheters. Agents that increase the concentration of cyclic AMP (cAMP) in platelets (PGE1, adenosine, dibutyryl cAMP, forskolin, and papaverine) also decreased platelet density. This effect persisted when the platelets were washed and resuspended in fresh medium and was also demonstrable in plasma. Platelet size was gradually increased by prostaglandin E1 (PGE1) which maintains platelets in a disc shape and does not cause the release of granule contents, indicating that the decrease in platelet density caused by PGE1 may be attributable to platelet swelling.