Outcomes of preimplantation genetic diagnosis using either zona drilling with acidified Tyrode's solution or partial zona dissection / 대한생식의학회지

OBJECTIVE: To review the outcomes of preimplantation genetic diagnosis (PGD) using zona drilling with acid Tyrode's solution (chemical zona pellucida drilling, chemical ZD) and those of partial zona dissection (PZD). METHODS: Clinical outcomes of seventy-one couples undergoing 85 PGD cycles from January 2005 to December 2010 were included. Blastocyst formation and the hatching rate, clinical pregnancy rate, ongoing pregnancy rate, implantation rate, and fetal gender ratio of the PZD and chemical ZD groups were compared. RESULTS: Application of PZD resulted in a significantly higher rate of clinical pregnancy (40.7% vs. 15.4%, p=0.022), ongoing pregnancy (35.6% vs. 11.5%, p=0.023), and implantation (18.1% vs. 5.7%, p=0.007) compared with chemical ZD. Among non-transferred embryos, the rate of blastocyst formation on day 5 (49.1% vs. 39.5%, p=0.016) and hatching on day 6 (47.2% vs. 26.5%, p<0.001) were also significantly higher in the PZD group. CONCLUSION: The mechanical zona dissection method showed better outcomes than chemical ZD in terms of the blastocyst development and pregnancy rate. In this study, the fact that chemical ZD was conducted in different period from mechanical method should be considered in interpreting the result.

Influence of Ischemic-Simulation on the Action Potential Characteristics in Rat Atrial Fibers

BACKGROUND: To investigate the mechanisms of myocardial ischemia induced changes of electrophysiological properties, influences of various ischemic-simulated Tyrode's solutions on the changes of action potential characteristics were examined. METHOD: Action potential characteristics were measured during superfusion with various ischemic-simulated solutions (modified physiologic salt solution: MPSS) by the method of conventional microelectrode technique in rat atrial fibers. RESULTS: Hypoxic-, hyperkalemic-, and mixed-MPSS decreased 'maximum diastolic potential' (MDP) and 'action potential amplitude' (APA), however, no significant changes of MDP and APA were observed by acidic- and glucose-free-MPSS. 'Maximum velocity of phase 0 depolarization' (dV/dt(max)) and 'time for 90% repolarization' (APD90) significantly decreased during hypoxic- and mixed-MPSS superfusion, and hyperkalemic-MPSS also decreased the dV/dt(max) and APD90. However, no significant changes in dV/dt(max) and APD90 were observed by acidic- and glucose-free-MPSS. The decreasing effects of dV/dt(max) and APD90 by the MPSSes were attenuated when the MPSSes were replaced with normal Tyrode's solution. DPCPX (2x10(-6)M), a purinergic antagonist, inhibited the decreasing effects of APD90 at 5, 10, and 20 min superfusion of the mixed-MPSS, and glibenclamide (10(-6)M), a K(ATP) channel blocker, inhibited those at 10 and 20 min superfusion of the mixed-MPSS. Diclofenac (10(-6)M), a cyclooxygenase inhibitor inhibited only those at 20 min superfusion of the mixed-MPSS. CONCLUSION: The primary factors for changing the electrophysiological characteristics during ischemic insults could be hypoxia and high-extracellular K+, and the mechanisms of the electrophysiological changes are inferred that adenosine through purinoceptors is involved initially, and followed by K(ATP) channel and prostanoids.