Developmental ability of trophoblast stem cells in uniparental mouse embryos

Neither parthenogenetic (PG) nor androgenetic (AG) mouse embryos survive after day 9.5 of pregnancy, owing to the inadequate growth of extraembryonic tissues, including the placenta. At day 9.5 of pregnancy, the placental structures are poorly developed in PG embryos, while trophoblast giant cells are abundant at the implantation site in AG embryos. These findings suggest that both parental genomes are required for placental development. To gain further insight into the trophoblast lineage in PG and AG embryos, we attempted to derive trophoblast stem (TS)-like cell lines from uniparental embryos. Furthermore, we sought to assess their ability to differentiate into cells of the trophoblast lineage by using gene expression analysis. Three cell lines that expressed marker genes for undifferentiated TS cells (Cdx2 and Errbeta) were derived from AG embryos. Under differentiation conditions, these cells expressed the trophoblast giant cell-specific genes, but did not express the spongiotrophoblast-specific genes. In contrast, none of the four cell lines from PG embryos expressed marker genes for undifferentiated TS cells, but they expressed Oct3/4, a marker gene for embryonic stem cells. Immunohistochemical analysis indicated that PG blastocysts expressed Oct3/4 and Cdx2 specifically in inner cell mass and the trophectoderm respectively. These results suggest that PG embryos do not possess TS cells, because of the lack of the developmental ability of trophoblast cells.

Glycine receptors mediate excitation of subplate neurons in neonatal rat cerebral cortex

The development of the cerebral cortex depends on genetic factors and early electrical activity patterns that form immature neuronal networks. Subplate neurons (SPn) are involved in the construction of thalamocortical innervation, generation of oscillatory network activity, and in the proper formation of the cortical columnar architecture. Because glycine receptors play an important role during early corticogenesis, we analyzed the functional consequences of glycine receptor activation in visually identified SPn in neocortical slices from postnatal day 0 (P0) to P4 rats using whole cell and perforated patch-clamp recordings. In all SPn the glycinergic agonists glycine, beta-alanine, and taurine induced dose-dependent inward currents with the affinity for glycine being higher than that for beta-alanine and taurine. Glycine-induced responses were blocked by the glycinergic antagonist strychnine, but were unaffected by either the GABAergic antagonist gabazine, the N-methyl-d-aspartate-receptor antagonist d-2-amino-5-phosphonopentanoic acid, or picrotoxin and cyanotriphenylborate, antagonists of alpha-homomeric and alpha1-subunit-containing glycine receptors, respectively. Under perforated-patch conditions, glycine induced membrane depolarizations that were sufficient to trigger action potentials (APs) in most cells. Furthermore, glycine and taurine decreased the injection currents as well as the synaptic stimulation strength required to elicit APs, indicating that glycine receptors have a consistent excitatory effect on SPn. Inhibition of taurine transport and application of hypoosmolar solutions induced strychnine-sensitive inward currents, suggesting that taurine can act as a possible endogenous agonist on SPn. In summary, these results demonstrate that SPn express glycine receptors that mediate robust excitatory membrane responses during early postnatal development.

Pseudospin soliton in the nu=1 bilayer quantum Hall state

We investigate a domain structure of pseudospins, a soliton lattice in the bilayer quantum Hall state at total Landau level filling factor nu = 1, in a tilted magnetic field, where the pseudospin represents the layer degree of freedom. An anomalous peak in the magnetoresistance Rxx appears at the transition point between the commensurate and incommensurate phases. The Rxx at the peak is highly anisotropic for the angle between the in-plain magnetic field B parallel and the current, and indicates a formation of the soliton lattice aligned parallel to B parallel. The temperature dependence of the Rxx peak reveals that the dissipation is caused by thermal fluctuations of pseudospin solitons. We also study a phase diagram of the bilayer nu = 1 system, and the effects of density imbalance between the two layers.

Efficacy of living donor liver transplantation for patients with methylmalonic acidemia

Application of liver transplantation to methylmalonic acidemia (MMAemia) is controversial because MMAemia is caused by a systemic defect of methylmalonyl-CoA mutase. The clinical courses of seven pediatric patients with MMAemia undergoing living donor liver transplantation (LDLT) were reviewed. Serum and urinary methylmalonic acid (MMA) levels were found to be significantly decreased after LDLT, whereas serum and urinary MMA levels did not return to normal in any patient. One patient died of sepsis 44 days after LDLT. The other six patients are currently doing well. All patients had preoperative history of acute metabolic decompensation and/or metabolic stroke. However, no episode of acute metabolic decompensation or metabolic stroke was observed postoperatively in any surviving patients. In the preoperative period, all patients showed lethargy and cognitive deficit, both of which were eradicated after LDLT in all surviving patients. Preoperatively, all patients were subjected to dietary protein intake restriction and tube feeding, and were administered several metabolism-correcting medications. The metabolism-correcting medications being administered remained mostly unchanged after LDLT, whereas protein restriction was liberalized and tube feeding became unnecessary in all surviving patients. In addition, physical and neurodevelopmental growth delay remained in all surviving patients during the observation period, which ranged from 4 to 21 months with a median of 10.5 months.

Large-scale gene expression profiles, differentially represented in osteoarthritic synovium of the knee joint using cDNA microarray technology

Osteoarthritis (OA) is one of the most common age-related chronic disorders of articular cartilage, joints and bone tissue. Diagnosis of OA commonly depends on clinical and radiographic findings. However, changes in cartilage associated with the early stage of OA cannot be detected using radiographs, because significant cartilage degeneration must occur before radiographic findings show alterations of the appearance of cartilage. To identify new biomarkers of OA, we analysed gene expression profiles of synovium from 43 patients with OA, ten patients with rheumatoid arthritis (RA), and eight non-OA/non-RA patients using a novel cDNA microarray chip. We identified 21 genes with simultaneous significant differences in expression between OA and non-OA/non-RA groups and between OA and RA groups. Linear discriminant analysis showed that the three groups could be well separated using those 21 genes. Statistical analysis also revealed that several of the 21 genes were associated with disease progression and clinical presentation. The graphical modelling method indicated that some of the 21 genes are significantly associated with a particular clinical presentation, suggesting biological relationships among those genes. This is the first report of the use of cDNA microarray technology to create large-scale gene expression profiles differentially expressed in situ in OA synovium of the knee joint.