Tales of the Tail and Sperm Head Aches --Changing concepts on the prognostic significance of sperm pathologies affecting the head, neck and tail

This article presents an update on the variable prognostic significance of different sperm pathologies in patients with severe male factor infertility due to morphology and motility disorders. Severe asthenozoospermia is one of the leading causes of male infertility as spermatozoa cannot reach the oocyte and/or penetrate normally. Identifying structural causes of sperm immotility was of great concern before the advent of intracytoplasmic sperm injection （ICSI）, because immotility was the limiting factor in the treatment of these patients. In these cases, in vitro methods are used to identify live spermatozoa or stimulate sperm motility to avoid selection of non-viable cells. With these advances, fertilization and pregnancy results have improved dramatically. The identification of genetic phenotypes in asthenozoospermia is important to adequately inform patients of treatment outcomes and risks. The one sperm characteristic that seriously affects fertility prognosis is teratozoospermia, primarily sperm head and neck anomalies. Defects of chromatin condensation and acrosomal hypoplasia are the two most common abnormalities in severe teratozoospermia. The introduction of microscopic methods to select spermatozoa and the development of new ones to evaluate sperm quality before ICSI will assure that ultrastructural identification ofsperm pathologies will not only be of academic interest, but will also be an essential tool to inform treatment choice. Herein, we review the differential roles played by sperm components in normal fertilization and early embryo development and explore how assisted reproductive technologies have modified our concepts on the prognostic significance of sperm pathologies affecting the head, neck, mid-piece and tail.

Investigation of morphology selection for CBr_4-C_2Cl_6 alloy in three dimensions with multi-phase field method

With the multi-phase field model, the unidirectional solidification with constant velocity growth and variable velocity growth of the CBr4-C2C16 eutectic alloy is simulated in three dimensions. The simulated results with constant velocity growth show that with the increase of pulling velocity, the morphology of the CBr4-C2C16 alloy evolves in the sequence of lamellar merging -lamellar-rod transition-stable lamellar growth-oscillating growth-lamellar branching. A morphology selection map is established with different pulling velocities, which is confirmed to be correct by the velocity change process. It is shown that all of the morphology transitions, the average interface growth velocity and average interface undercooling show a hysteresis effect against the instant of velocity change. The relationship between the interface average undercooling and interface average growth velocity is consistent with the theoretical value.

Mechanisms of selective head cooling for resuscitating damaged neurons during post-ischemic reperfusion

Objective To evaluate the efficacy and the mechanism of application of selective head cooling on neuronal morphological damage during postischemic reperfusion in a rabbit model.Methods 168 New Zealand rabbits were randomized into three groups. Group Ⅰ [n=24, (38±0.5)℃, non-ischemic control]; Group Ⅱ [n=72, (38±0.5)℃, normothermic reperfusion]; Group Ⅲ [n=72, (28±0.5)℃, selective head cooling, initiated at the beginning of reperfusion). Animals in three subgroups (n=24, each) of Group Ⅱ and Group Ⅲ had reperfused lasting for 30, 180 and 360 min respectively. Using computerized image analysis technique on morphological changes of nucleus, the degree of neuronal damage in 12 regions were differentiated into type A (normal), type B (mild damaged), type C (severely damaged) and type D (necrotic). Fourteen biochemical parameters in brain tissues were measured.[KH*2/5D]Results As compared with Group Ⅰ, the counts of type A neuron decreased progressively, and those of type B, C and D increased significantly in Group Ⅱ during reperfusion (P【0.01). In Group Ⅱ, vasoactive intestinal peptide, b-endorphine, prostacyclin, T 3 and Na +, K +-ATPase were correlated with the changes of type A; b-endorphine and thromboxane with type B; glucose and vasopressin with type C; Na +, K +-ATPase, glutamic acid, T 3 and vasoactive intestinal peptide with type D (P【0.05). As compared with Group Ⅱ, the counts of type A increased, and those of type C and D significantly decreased in Group Ⅲ (P【0.01). In Group Ⅲ, Ca 2+ , Mg 2+ -ATPase were correlated with the changes of type A, C and D (P【0.01). Conclusion Selective head cooling for sex hours during postischemic reperfusion does improve neuronal morphological outcomes in terms of morphological changes.