Comparison of intrauterine hematologic and biochemical values between twin pairs with and without stuck twin syndrome.

OBJECTIVE: Our purpose was to compare hematologic and biochemical values in cordocentesis specimens from twin pairs with and without stuck twin syndrome. STUDY DESIGN: Cordocentesis was performed on 38 twin pairs. Assignment to the stuck twin syndrome group (n = 8) was based on ultrasonographic findings of discordant size and amniotic fluid volume, concordant gender, and a single placenta. A receiver-operator characteristic curve was constructed with the use of intertwin hemoglobin differences. For the stuck twin syndrome group regression analysis of gestational age and intertwin hemoglobin difference was done. RESULTS: We found significant (p = 0.03) intertwin differences in hemoglobin between the stuck twin syndrome group (mean 5.35 gm/dl, range 0.5 to 15.4 gm/dl) and the comparison group (mean 0.10 gm/dl, range 0.0 to 2.4 gm/dl). A nearly significant relationship between gestational age and intertwin hemoglobin difference was noted in the stuck twin syndrome group. When the hemoglobin difference was > 2.4 gm/dl, all cases had stuck twin syndrome (sensitivity = 50%, specificity = 100%, positive predictive value = 100%, negative predictive value = 91%). In the stuck twin syndrome group there was a trend toward larger intertwin differences in albumin and total protein. Intertwin blood gas values between the groups did not differ, but the average PO2 was lower when the smaller twins of the two groups were compared. CONCLUSION: An intertwin difference in hemoglobin > 2.4 gm/dl is consistent with stuck twin syndrome. Large intertwin hemoglobin differences and imbalances in albumin and total protein may be seen in stuck twin syndrome.

Effect of glycine and glycine receptor antagonists on NMDA-induced brain injury.

In postnatal day 7 rats, a unilateral intrastriatal injection of 12.5 nmol of N-methyl-D-aspartate (NMDA) reproducibly injures the ipsilateral striatum, adjacent hippocampus and overlying cortex. The severity of injury can be quantified by comparing cerebral hemisphere weights in animals sacrificed 5 days after the injection. Co-injection of NMDA and the glycine receptor antagonists kynurenic acid (KYN) or 7-chlorokynurenic acid (7-CKA) reduced the severity of NMDA-induced damage in a dose-dependent fashion. One hundred nmol of KYN with 12.5 nmol of NMDA reduced average % damage from 19.3 +/- 0.9% (n = 9) to 2.3 +/- 0.5% (n = 6), P less than 0.001, ANOVA. Co-injection of 40 nmol of 7-CKA with 12.5 nmol of NMDA (n = 6) reduced average % damage from 17.1 +/- 1.6% (n = 15) to 3.0 +/- 0.6%, P less than 0.001, ANOVA. Concurrent injection of 1000 nmol glycine with 5 nmol NMDA did not increase the extent of NMDA-induced damage. Our results demonstrate that glycine receptor antagonists attenuate NMDA-induced brain injury in vivo.