Superconductivity in a unique type of copper oxide.

The mechanism of superconductivity in cuprates remains one of the big challenges of condensed matter physics. High-T c cuprates crystallize into a layered perovskite structure featuring copper oxygen octahedral coordination. Due to the Jahn Teller effect in combination with the strong static Coulomb interaction, the octahedra in high-T c cuprates are elongated along the c axis, leading to a 3dx 2-y 2 orbital at the top of the band structure wherein the doped holes reside. This scenario gives rise to 2D characteristics in high-T c cuprates that favor d-wave pairing symmetry. Here, we report superconductivity in a cuprate Ba2CuO4-y , wherein the local octahedron is in a very exceptional compressed version. The Ba2CuO4-y compound was synthesized at high pressure at high temperatures and shows bulk superconductivity with critical temperature (T c ) above 70 K at ambient conditions. This superconducting transition temperature is more than 30 K higher than the T c for the isostructural counterparts based on classical La2CuO4 X-ray absorption measurements indicate the heavily doped nature of the Ba2CuO4-y superconductor. In compressed octahedron, the 3d3z 2-r 2 orbital will be lifted above the 3dx 2-y 2 orbital, leading to significant 3D nature in addition to the conventional 3dx 2-y 2 orbital. This work sheds important light on advancing our comprehensive understanding of the superconducting mechanism of high T c in cuprate materials.

Li(Cd,Mn)P: a new cadmium based diluted ferromagnetic semiconductor with independent spin & charge doping.

We report a new diluted ferromagnetic semiconductor Li1+y(Cd,Mn)P, wherein carrier is doped via excess Li while spin is doped by isovalence substitution of Mn2+ into Cd2+. The extended Cd 4d-orbitals lead to more itinerant characters of Li1+y(Cd,Mn)P than that of analogous Li1+y(Zn,Mn)P. A higher Curie temperature of 45 K than that for Li1+y(Zn,Mn)P is obtained in Li1+y(Cd,Mn)P polycrystalline samples by Arrott plot technique. The p-type carriers are determined by Hall effect measurements. The first principle calculations and X-ray diffraction measurements indicate that occupation of excess Li is at Cd sites rather than the interstitial site. Consequently holes are doped by excess Li substitution. More interestingly Li1+y(Cd,Mn)P shows a very low coercive field (<100 Oe) and giant negative magnetoresistance (~80%) in ferromagnetic state that will benefit potential spintronics applications.

[Selection criteria for liver transplantation recipients of hepatocellular carcinoma].

Liver transplantation is by far the most thorough and effective treatment for liver cancer. However, there is still much controversy about how to select receptors in an effective and equitable manner under the shortage of liver donor. The "Milan Standard" is the most widely used screening standard for liver transplantation recipients in the world. In recent years, many patients with Trans Milan criteria (such as Hangzhou standard) can achieve transplant survival similar to that of Milan patients after transplantation. This article describes the research progress of liver transplantation recipients' selection criteria in hepatocellular carcinoma.

Expression and tyrosine phosphorylation of sp32 regulate the activation of the boar proacrosin/acrosin system.

The current study investigated the relationship between the level of expression and tyrosine phosphorylation of the sperm protein 32 (sp32) and the activation of the boar proacrosin/acrosin system. The acrosomal membrane proteins of boar sperm for use in different treatment experiments (i.e., fresh sperm, freezing and thawing, capacitation, and acrosome reaction) were separated, stained by Coomassie brilliant blue, and analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot. The results showed that there were differences in the expression level of sp32 among capacitated, frozen-thawed, and post acrosomal reaction sperms. sp32 expression was higher and significantly higher in capacitated and post-acrosomal reaction sperms than in frozen-thawed sperms and fresh semen, respectively. The level of sp32 tyrosine phosphorylation was significantly different between the frozen-thawed sperms and sperms in the other experimental groups. However, bands with molecular masses of 38 to 170 ku in the fresh semen group were more noticeable, indicating that large acrosomal membrane proteins underwent modification and degradation during capacitation and the acrosomal reaction. As a proacrosin binding protein, sp32 shows upregulated expression and increase in tyrosine phosphorylation levels during the activation of the boar proacrosin/acrosin system.

Retromer-dependent neurotransmitter receptor trafficking to synapses is altered by the Parkinson's disease VPS35 mutation p.D620N.

Vacuolar protein sorting 35 (VPS35) is a core component of the retromer complex, crucial to endosomal protein sorting and intracellular trafficking. We recently linked a mutation in VPS35 (p.D620N) to familial parkinsonism. Here, we characterize human VPS35 and retromer function in mature murine neuronal cultures and investigate neuron-specific consequences of the p.D620N mutation. We find VPS35 localizes to dendritic spines and is involved in the trafficking of excitatory AMPA-type glutamate receptors (AMPARs). Fundamental neuronal processes, including excitatory synaptic transmission, AMPAR surface expression and synaptic recycling are altered by VPS35 overexpression. VPS35 p.D620N acts as a loss-of-function mutation with respect to VPS35 activity regulating synaptic transmission and AMPAR recycling in mouse cortical neurons and dopamine neuron-like cells produced from induced pluripotent stem cells of human p.D620N carriers. Such perturbations to synaptic function likely produce chronic pathophysiological stress upon neuronal circuits that may contribute to neurodegeneration in this, and other, forms of parkinsonism.

Myf5 gene polymorphisms and production performance traits in Songliao white geese.

To explore the relationship between Myf5 gene polymorphisms and production performance traits in Songliao white geese, we used the chicken Myf5 sequence to design primers and amplified part of the exon 1 sequence of the Songliao white goose Myf5 gene. Results of single-strand conformation polymorphism polymerase chain reaction analysis revealed polymorphisms of the amplified fragment, including three genotypes (AA, AB, and BB). Three varieties were dominated by allele A and were mainly expressed in AA genotypes. We also identified that the Myf5 gene has one single nucleotide change (A→G) on exon 1 at locus 1344, and another (G→C) at locus 1410. Analysis of variance showed significant differences between genotypes before slaughter in live weight, carcass weight, eviscerated weight, leg muscle weight, weight of the wings, and slaughter rate. There were no significant differences with respect to other growth and carcass traits evaluated.

Orthotopic abdominal multivisceral transplantation without venovenous bypass in pigs.

BACKGROUND: Because venovenous bypass (VVB) can cause specific complications, a simplified orthotopic abdominal multivisceral transplantation (MVTX) technique without VVB in pigs has been evaluated in terms of morbidity and mortality. MATERIALS AND METHODS: Outbred large-white pigs weighing 25 to 40 kg of random sex underwent MVTX operation. After in situ cold perfusion through the aorta and superior mesenteric vein, the multivisceral allograft was procured from the donor and tailored at the back table. The multivisceral allograft, including liver, pancreas, stomach, duodenum, and proximal 2 m of jejunum, was en bloc transplanted into recipient after resection of entire foregut and midgut; VVB was not used. We analyzed the hemodynamic change, arterial blood gas data, and fluid requirements intraoperatively. RESULTS: Among 25 MVTXs, 19 (76%) animals survived after the operation. Without using an immunosuppressant, postoperative survival time was 2 to 146 hours. Ten recipient pigs died within 24 hours. Seven animals were lost between postoperative days 2 and 5. Two pigs survived for more than 5 days. The recipient pigs were mostly in a state of hypovolemic shock and metabolic acidosis during the reperfusion phase. CONCLUSIONS: Despite a high morbidity and mortality, the simplified technique without VVB is feasible to successfully achieve MVTX in the pig.

Als2-deficient mice exhibit disturbances in endosome trafficking associated with motor behavioral abnormalities.

ALS2 is an autosomal recessive form of spastic paraparesis (motor neuron disease) with juvenile onset and slow progression caused by loss of function of alsin, an activator of Rac1 and Rab5 small GTPases. To establish an animal model of ALS2 and derive insights into the pathogenesis of this illness, we have generated alsin-null mice. Cytosol from brains of Als2(-/-) mice shows marked diminution of Rab5-dependent endosome fusion activity. Furthermore, primary neurons from Als2(-/-) mice show a disturbance in endosomal transport of insulin-like growth factor 1 (IGF1) and BDNF receptors, whereas neuronal viability and endocytosis of transferrin and dextran seem unaltered. There is a significant decrease in the size of cortical motor neurons, and Als2(-/-) mice are mildly hypoactive. Altered trophic receptor trafficking in neurons of Als2(-/-) mice may underlie the histopathological and behavioral changes observed and the pathogenesis of ALS2.

The role of SHIP1 in macrophage programming and activation.

The SHIP1 (SH2-containing inositol-5'-phosphatase 1) acts as a negative regulator of proliferation, survival and end cell activation in haemopoietic cells. It does so, at least in part, by translocating to membranes after extracellular stimulation and hydrolysing the phosphoinositide 3-kinase-generated second messenger, PtdIns(3,4,5)P(3) to PtdIns(3,4)P(2). SHIP1(-/-) mice have, as a result, an increased number of neutrophils and monocyte/macrophages because their progenitors display enhanced survival and proliferation. These mice also suffer from osteoporosis because of an increased number of hyperactive osteoclasts and a significant neutrophil infiltration of the lungs. Interestingly, SHIP1(-/-) mice do not display endotoxin tolerance and we have found that lipopolysaccharide-induced endotoxin tolerance is contingent on up-regulating SHIP1, through the production of autocrine-acting transforming growth factor-beta, in bone-marrow-derived macrophages and mast cells. Intriguingly, unlike bone-marrow-derived macrophages, SHIP1(-/-) peritoneal and alveolar macrophages produce 10-fold less NO than wild-type macrophages because these in vivo-generated macrophages have very high arginase I levels and this enzyme competes with inducible nitric oxide synthase for the substrate L-arginine. It is probable that, in the face of chronically increased PtdIns(3,4,5)P(3) levels in their myeloid progenitors, SHIP1(-/-) mice display a skewed development away from M1 (killer) macrophages (which have high inducible nitric oxide synthase levels and produce NO to kill microorganisms and tumour cells), towards M2 (healing) macrophages (which have high arginase levels and produce ornithine to promote host-cell growth and collagen formation). This skewing probably occurs to avoid septic shock and suggests that the phosphoinositide 3-kinase pathway plays a critical role in programming macrophages.

The role of SHIP in cytokine-induced signaling.

The phosphatidylinositol (PI)-3 kinase (PI3K) pathway plays a central role in regulating many biological processes via the generation of the key second messenger PI-3,4,5-trisphosphate (PI-3,4,5-P3). This membrane-associated phospholipid, which is rapidly, albeit transiently, synthesized from PI-4,5-P2 by PI3K in response to a diverse array of extracellular stimuli, attracts pleckstrin homology (PH) domain-containing proteins to membranes to mediate its many effects. To ensure that the activation of this pathway is appropriately suppressed/terminated, the ubiquitously expressed tumor suppressor PTEN hydrolyzes PI-3,4,5-P3 back to PI-4,5-P2 while the 145-kDa hemopoietic-restricted SH2-containing inositol 5'- phosphatase, SHIP (also known as SHIP1), the 104-kDa stem cell-restricted SHIP (sSHIP) and the more widely expressed 150-kDa SHIP2 hydrolyze PI-3,4,5-P3 to PI-3,4-P2. In this review we will concentrate on the properties of the three SHIPs, with special emphasis being placed on the role that SHIP plays in cytokine-induced signaling.

Effects of vitamin D receptor inactivation on the expression of calbindins and calcium metabolism.

Hypocalcemia, rickets, and osteomalacia are major phenotypic abnormalities in vitamin D receptor (VDR)-null mice. In an attempt to understand the abnormal regulation of calcium metabolism in these animals, we examined the expression of calbindins (CaBP) as well as calcium handling in the intestine and kidney of VDR null mice. In adult VDR-null mice, intestinal and renal CaBP-D9k expression was reduced by 50 and 90%, respectively, at both the mRNA and protein levels compared with wild-type littermates, whereas renal CaBP-D28k expression was not significantly changed. Intestinal calcium absorption was measured by the rate of (45)Ca disappearance from the intestine after an oral dose of the isotope. (45)Ca absorption was similar in VDR-null and wild-type mice, but the amount of (45)Ca accumulated in the serum and bone was 3-4 times higher in wild-type mice than in VDR-null mice. Despite the hypocalcemia, the urinary excretion of calcium in VDR-null mice was not different from that in wild-type mice. Moreover, 1 wk of a high-calcium diet treatment that normalized the serum ionized calcium level of VDR-null mice increased the urinary calcium level of these mutant mice to twofold higher than that of wild-type mice on the same diet, suggesting impaired renal calcium conservation in VDR-null mice. These data demonstrate that renal CaBP-D9k, but not CaBP-D28k, is highly regulated by the VDR-mediated action of 1,25-dihydroxyvitamin D(3). Furthermore, the results also suggest that impaired calcium conservation in the kidney may be the most important factor contributing to the development of hypocalcemia in VDR-null mice, and CaBP-D9k may be an important mediator of calcium reabsorption in the kidney.

[Studies on esterase isoenzyme of three species of flea].

The patterns of esterase (Est) isoenzyme of 3 flea species were studied by vertical slab polyacrylamide gel electrophoresis (PAGE). The samples prepared from the third larval instar, female and male (the unsucking and sucked one) were run in the same gel slab. The result was as follows: Xenopsylla cheopis showed 14 bands, with 5-6 major bands, Ctenocephalides felis felis showed 9 bands with 4-5 major bands and Nosopsyllus laeviceps kuzenkovi showed 9 bands with 4-5 major bands. These three species have their common bands as well as respective specific bands. The difference in Est isoenzymogram among families was greater than among genera, displaying a species-specific feature.