The biological characteristics of human third trimester amniotic fluid stem cells

Third trimester amniotic fluid (AF)-derived human mesenchymal stem cells (MSCs) can be greatly expanded in vitro and induced to differentiate into multiple mesenchymal cell types. This study aimed to investigate the biological characteristics of MSCs from third trimester AF as a new source of therapeutic stem cells. Forty third trimester AF samples were obtained from healthy women who underwent elective caesarean section for breech presentation. A simple culture protocol for MSCs was used. A cell growth curve was drawn, and cell surface antigens and cytokines were analysed by immunofluorescent staining, reverse transcription-polymerase chain reaction and flow cytometry. MSCs from third-trimester AF were successfully isolated, cultured and enriched. MSCs expanded extensively without feeders, they were not tumourigenic and were induced to differentiate into osteocytes. Surface antigens were analysed and found to express the pluripotency marker Oct-4. Considering the great feasibility of biomedical engineering using MSCs, third trimester AF may provide a rich source for investigation of human MSCs.

First Report of the Soybean Cyst Nematode, Heterodera glycines, on Soybean in Zhejiang, Eastern China

The soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is a destructive pest of soybean. Damage to soybean by SCN was first reported from northeastern China in 1899 (1). SCN has been documented in Anhui, Beijing, Hebei, Heilongjiang, Henan, Jiangsu, Jilin, Liaoning, Neimenggu, Shaanxi, Shandong, and Shanxi provinces in mainland China (1). These provinces are situated in the Heilongjiang and Songhuajing valleys in northeastern China and the eastern region of the Yangtze and Yellow rivers in northern China and have cold to temperate climates. In June of 2008, cyst-forming nematodes were detected in two soybean-growing areas of Hangzhou and Xiaoshan in Zhejiang Province, in subtropical eastern China. The soybean plants at the Hangzhou site showed symptoms of stunting and chlorosis, whereas no aboveground or root symptoms were observed on soybean plants at the Xiaoshan site, except for the presence of SCN females on the roots. The two populations had the same morphological and molecular characters. The cysts were lemon shaped with posterior protuberance, ambifenestrate, underbridge and bullae strongly developed, and lateral field of second-stage juveniles consisted of four incisures. The key morphometrics of cysts were fenestra length (41 to 52 μm) and width (33 to 48 μm), vulval silt (47 to 55 μm), and underbridge length (79 to 94 μm), all of which were coincident with that of SCN (2). Amplification of rDNA-internal transcribed spacer (ITS) region using primers TW81 (5'-GTT TCC GTA GGT GAA CCT GC-3') and AB28 (5'-ATA TGC TTA AGT TCA GCG GGT-3') yielded a PCR fragment of approximately 1,030 bp. The digestion patterns of the PCR fragments of the ITS region with AluI, AvaI, CfoI, MvaI, and RsaI showed identical restriction profiles to H. glycines (3), and the sequences exhibited 100% similarity with those of H. glycines isolates, Accession No. AY667456 from GenBank. Morphological and molecular identification confirmed that the two populations of cyst-forming nematodes from Zhejiang are SCN. To our knowledge, this is the first report of SCN in Zhejiang, now the most southern location in mainland China with confirmed infestation of SCN. References: (1) Z. X. Liu et al. Int. J. Nematol. 7:18, 1997. (2) R. H. Mulvey. Can. J. Zool. 50:1277, 1972. (3) J. Zheng et al. Russ. J. Nematol. 8:109, 2000.

Photocatalytic hydrogen generation over lanthanum doped TiO2 under UV light irradiation

TiO2 nanoparticles doped with different amount of lanthanum were obtained by sol-gel approach and followed annealing at different temperature. The crystal size of TiO2 doped with lanthanum was smaller than that of pure TiO2. Photocatalytic activity of TiO2 doped with lanthanum for water splitting into H2 was investigated. The photocatalytic activity of TiO2 doped with lanthanum for water splitting into H2 is higher than that of pure TiO2. It was found that the optimal photocatalyst was TiO2 doped with 2 wt% lanthanum and calcined at 600 degrees C for 4 h which had hydrogen generation rate 700.6 micromol h(-1).

Extracellular hypotonicity induces disturbance of sodium currents in rat ventricular myocytes

Hypotonic solution alters ion channel activity, but little attention has been paid to voltage-dependent sodium channels. The aim of this study was to investigate the effects of hypotonic solution on transient sodium currents (INaT) and persistent sodium currents (INaP). We also explored whether the intracellular signal transduction systems participated in the hypotonic modifications of sodium currents. INaT and INaP were recorded by means of whole-cell patch-clamp technique in isolated rat ventricular myocytes. Our results revealed that hypotonic solution reduced INaT and simultaneously augmented INaP with the occurrence of interconversion between INaT and INaP. Hypotonic solution shifted steady-state inactivation to a more negative potential, prolonged the time of recovery from inactivation, and enhanced intermediate inactivation (IIM). Ruthenium red (RR, inhibitor of TRPV4), bisindolylmaleimide VI (BIM, inhibitor of PKC), Kn-93 (inhibitor of Ca/CaMKII) and BAPTA (Ca2+-chelator) inhibited the effects of hypotonic solution on INaT and INaP. Therefore we conclude that hypotonic solution inhibits INaT, enhances INaP and IIM with the effects being reversible. TRPV4 and intracellular Ca2+, PKC and Ca/CaMKII participate in the hypotonic modifications of sodium currents.

Ghrelin regulates gastric phase III-like contractions in freely moving conscious mice

In humans and dogs, motilin regulates phase III contractions of migrating motor complex (MMC) in the interdigestive state, while ghrelin regulates MMC in rats. It still remains unclear whether ghrelin regulates phase III contractions of the mouse stomach. A miniature strain gauge transducer was sutured on the antrum to detect circular muscle contractions and gastric contractions of the interdigestive state were evaluated. Effects of ghrelin, a ghrelin receptor antagonist, and atropine on spontaneous gastric contractions were studied in freely moving conscious mice. Similar to the rat stomach, phase III-like contractions were observed in the interdigestive state, which disappeared immediately after the feeding. Ghrelin augmented spontaneous phase III-like contractions, while growth-hormone secretagogue receptor antagonists and atropine abolished the occurrence of spontaneous phase III-like contractions. The spontaneous phase III-like contractions were no more observed in vagotomized mice. These results suggest that ghrelin regulates phase III-like contractions in mice stomach via its own receptors. Ghrelin-induced gastric phase III-like contractions are mediated via vagal cholinergic pathways in mice. Our recording system of mice gastric motility may be useful to study the functional changes in gene knockout mice, in the future.

Isolation and sequence analysis of Sox genes in the red crucian carp (Carassius carassius red variety)

Sox genes encode a family of transcription factors which are characterized by the conserved HMG domain and are involved in a diverse range of developmental processes. Using degenerate primer PCR, 7 different sequences encoding the HMG domains of Sox1, Sox9 and Sox1 1b were cloned and sequenced from genomic DNA in the red crucian carp (Carassius carassius red variety). In the case of Sox1 and Sox1 1b, we found evidence of gene duplication. In the phylogenetic tree, two paralogs of Sox1 1b (Sox1 1b1 and Sox1 1b2) fit within the clade of Sox11, especially in the Sox 1b subfamily, not in the Sox1 1a subfamily. Three Sox1 sequences (Soxl-1, Soxl-2 and Sox1-3) which shared the same amino acid sequence were identified in the red crucian carp. At the nucleotide level, Soxl-1 shared the highest sequence similarity to the zebrafish Sox1a, and Sox1-2 and Sox1-3 showed the highest similarity to the zebrafish Sox1b. The phylogenetic tree clearly demonstrated that the red crucian carp Sox1-1 clustered together with the zebrafish Sox1a, and the red crucian carp Sox1-2 and Sox1-3 with the zebrafish Sox1b. The result suggested that the red crucian carp Sox1-1, Soxl-2 and Sox1-3 were resulted from duplication of Sox1 gene rather than polymorphisms of the same gene.

Neuroprotective effect of deep hypothermic circulatory arrest with low priming volume: study in a rabbit model

OBJECTIVE

The aim of the study was to investigate the possible neuroprotective effects of a low priming volume following deep hypothermic circulatory arrest (DHCA) in a rabbit model.

METHODS

Rabbits were randomized into three groups: DHCA with low priming volume (Group L), DHCA with high priming volume (Group H), and sham-operated group (Group S). The priming volume of Groups L and H were 75 ml and 210 ml, respectively. The rabbits were simultaneously placed on CPB and brain microdialysis, cooled to 16 to 18 degrees C with DHCA for 60 minutes. Physiological parameters were regularly recorded. The extracellular levels of glutamate, glucose, lactate, and pyruvate in the hippocampus were collected by microdialysis and measured by HPLC and a microdialysis analyzer. Brain damage was evaluated with light microscopy and electron microscopy and TUNEL staining.

RESULTS

In order to keep the mean arterial pressure and acid-base balance within defined physiological ranges, more doses of dopamine and sodium bicarbonate were administered in Group H than in Group L (P < 0.05). The ratios of lactate/glucose and lactate/pyruvate in Group H increased significantly compared with those in Group L from the beginning of weaning from CPB (P < 0.05). The levels of extracellular glutamate in the two DHCA groups increased significantly (P < 0.05). After weaning from CPB, the glutamate values in Group H remained at higher levels compared with those in Group L (P < 0.05). The percentage of injured neurons, TUNEL positive staining, and the mitochondria score of the hippocampus CA1 in Group H were significantly higher than in Group L (P < 0.05).

CONCLUSIONS

A low priming volume during DHCA could have a neuroprotective effect compared with a high priming volume.

Metabotropic glutamate receptors subtype 5 are necessary for the enhancement of auditory evoked potentials in the lateral nucleus of the amygdala by tetanic stimulation of the auditory thalamus

The lateral nucleus of the amygdala (LA) receives axonal projections from the auditory thalamus, the medial geniculate nucleus (MGN), and mediates auditory fear conditioning. Tetanic electrical stimulation of the MGN can induce long-term potentiation of acoustically-evoked responses (AEPs) recorded in the LA of anesthetized rats. The present study investigated the temporal development of tetanus-induced AEP potentiation recorded in the LA of anesthetized rats during the recording time up to 120 min after tetanization. In addition, the present study investigated whether the artificially-induced AEP potentiation is mediated by the metabotropic glutamate receptors subtype 5 (mGluR5). The results show that AEPs recorded in the LA to a broadband-noise burst were significantly enhanced immediately after tetanic but not low-frequency stimulation of the MGN. The AEP potentiation was well retained up to 120 min after tetanization. High-dose (1.5 microg/4 microl) microinjection of the selective antagonist of mGluR5, 2-methyl-6-(phenylethynyl)-pyridine (MPEP), into the ipsilateral lateral ventricle 30 min before tetanization completely blocked the AEP potentiation without affecting the baseline AEP. Low-dose (0.5 microg/4 microl) microinjection partially suppressed the AEP potentiation. When the high-dose MPEP was injected 40 min after tetanization, the AEP potentiation was not affected. These results indicate that in anesthetized rats mGluR5 receptors are necessary for the induction or early maintenance (40 min) of AEP potentiation in the LA by tetanic stimulation of the MGN.