A High-Performance Corrosion-Resistant Iron-Based Amorphous Metal - The Effects of Composition, Structure and Environment on Corrosion Resistance

The passive film stability of several Fe-based amorphous metal formulations have been found to be comparable to that of high-performance Ni-based alloys, and superior to that of stainless steels, based on electrochemical measurements of the passive film breakdown potential and general corrosion rates. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The high boron content of this particular amorphous metal also makes it an effective neutron absorber, and suitable for criticality control applications, as discussed in companion publications. Corrosion data for SAM2X5 (Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4) is discussed here.

Genetic structure of Eurasian and North American mallard ducks based on mtDNA data

To elucidate the origin and genetic structure of the domesticated duck in Eurasia and North America, we sequenced 114 duck D-loop sequences and retrieved 489 D-loop sequences from GenBank. In total, 603 ducks including 50 duck breeds/populations from eight countries (China, France, Russia, India, Kazakhstan, Mongolia, Thailand and USA) were used in this study. One hundred and thirty-four haplotypes and 81 variable sites were detected. H49 was the predominant haplotype, which was considered to be the same dominant haplotype found in the previous studies, and was found in 309 birds. The smallest values for both genetic differentiation index (F(ST), 0.04156) and the number of the net nucleotide substitutions between two populations (D(A), 0.00018) were observed between Eurasian domestic ducks and Eurasian mallards. No geography, breed or population clusters were observed in the Eurasian domestic ducks and mallards. Five haplotypes were shared by USA mallards and Eurasian domestic duck/Eurasian mallards. Only one haplotype (H49) was shared by Eurasian domestic ducks and China spot-billed ducks. By combining phylogenetic analyses, haplotype network profile, genetic distances and shared haplotypes, we can draw two major conclusions: (i) Eurasian and North American mallards show a clear geographic distribution pattern; (ii) Eurasian domestic ducks are derived from the Eurasian mallards, not from the spot-billed ducks.

Xenotransplantation of surgical specimens of human breast cancer directly into genetically engineered prolactin-humanized immunodeficient mice

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Background: Prolactin is an important hormone in mammary gland biology and is indispensible for lobulo-alveolar development during pregnancy and homeostasis during lactation. Prolactin has also been implicated in promoting proliferation, survival, and/ or differentiation of breast cancer. Importantly, murine and bovine prolactin, which are the major lactogens in current laboratory experimental conditions in vivo and in vitro, fail to effectively activate human prolactin receptors because of species incompatibility. Therefore, current established human breast cancer cell lines have been selected in the absence of human prolactin and do not represent the potential subgroup of cancers that depends on prolactin for survival or growth.

Methods: In an effort to improve in vivo preclinical modeling of human breast cancer and to establish new human breast cancer lines that are prolactin-dependent or prolactin-sensitive, we used genetic-engineering to generate a human prolactin knock-in mouse line, which expresses physiological levels of human prolactin in place of mouse prolactin. We have crossed the prolactin-humanized mouse line into the immunodeficient NSG strain for effective xenotransplantation studies. Fresh surgical specimens from breast cancer patients were directly transplanted orthotopically into female mice within 2 hours of surgery. We then followed the growth of the xenograft tumors over time and retransplanted the tumors if they engrafted.

Results: Our initial data suggested about a take rate of ~35% for the xenografted tumors. Estrogen receptor-positive luminal tumors usually have a very low engraftment rate in immunodeficient mice. However, we observed a relatively high rate of engraftment for luminal tumors.

Conclusions: This new prolactin-humanized mouse model is highly relevant for in vivo exploration of tumor biology and drug response testing of breast cancer, especially for luminal subtypes.

Hepatic artery thrombosis after liver transplantation: three case reports

OBJECTIVE

To explore the surgical techniques of hepatic artery reconstruction in liver transplantation (OLT) and the choice of treatment for hepatic artery thrombosis (HAT).

METHODS

We analyzed hepatic artery reconstructions based on 234 cadaveric donor liver transplantations and seven living related liver transplantations from April 2003 to February 2009. Anastomosis time was compared between the groups with respect to vascular caliber. Interventional thrombolysis or early thrombectomy and hepatic artery reconstruction was implemented in three HAT cases.

RESULTS

The hepatic artery anastomoses for vessels less than 3 mm in diameter (n = 78) required 33.6 ± 21.3 minutes which were significantly greater compared with those for vessels more than 3 mm in diameter (n = 163; 19.4 ± 7.4 minutes). Among two patients (0.83%) who developed early HAT within the first week after the operation, one was successfully treated by interventional thrombolysis, but the other required an urgent conduit between the aorta and the graft after attempted thrombolysis. Only one patient (0.41%) displayed a delayed HAT without special management, but recovered liver function upon follow-up.

DISCUSSION

Early detection and proper revascularization measures can yield satisfactory results after HAT.

A functionalized single-walled carbon nanotube-induced autophagic cell death in human lung cells through Akt-TSC2-mTOR signaling

Nanoparticles are now emerging as a novel class of autophagy activators. Functionalized single-walled carbon nanotubes (f-SWCNTs) are valuable nanomaterials in many industries. This article is designed to assess the autophagic response for f-SWCNTs exposure in vitro and in vivo. A few types of f-SWCNTs were screened in human lung adenocarcinoma A549 cells for the autophagic response and related pathways in vitro. Formation of autophagosomes and LC3-II upregulation were confirmed on the basis of electron microscopy and LC3 western blotting for COOH-CNT, but not for PABS-CNT and PEG-CNT. MTT assay showed marked increase in cell viability, when COOH-CNT was added to cells in the presence of autophagy inhibitor 3MA, ATG6 or TSC2 siRNA. Consistent with the involvement of the Akt–TSC1/2–mTOR pathway, the phosphorylation levels of mTOR, mTOR's substrate S6 and Akt were shown significantly decreased in A549 cells on treatment with COOH-CNT using western blotting. What's more, autophagy inhibitor 3MA significantly reduced the lung edema in vivo. In a word, COOH-CNT induced autophagic cell death in A549 cells through the AKT–TSC2–mTOR pathway and caused acute lung injury in vivo. Inhibition of autophagy significantly reduced COOH-CNT-induced autophagic cell death and ameliorated acute lung injury in mice, suggesting a potential remedy to address the growing concerns on the safety of nanomaterials.

Molecular identification of avian leukosis virus subgroup E loci and tumor virus B locus in Chinese indigenous chickens

Avian leukosis virus (ALV) subgroup E (ALVE) is an endogenous retrovirus in the chicken genome. The chickens carrying ALVE locus 3 (ALVE3), 6 (ALVE6), 9 (ALVE9), and 21 (ALVE21) have been proved to be susceptible to ALV. Tumor virus locus B (TVB) encodes the cellular receptor for ALV subgroups B, D, and E. The insertions of the 4 ALVE loci and the genotypes of TVB have not been demonstrated in Chinese indigenous chicken breeds. In the present study, the existence of ALVE3, ALVE6, ALVE9, and ALVE21 were detected in 10 native breeds of Chinese chickens and an introduced breed, the White Leghorn (2 populations in this study, WL1 and WL2), by locus-specific PCR. The PCR products of ALVE were further confirmed by sequencing assay. We also surveyed the status of genotypes of TVB in Silkie, Beijing You, and White Leghorn (WL1 and WL2) chickens with pyrosequencing assays. The results showed that the carrier frequency of ALVE3 was 1.3% in the Chinese chicken population, and was 10.3 in WL1 and 49.2% in WL2. The carrier frequency of ALVE6 was 5.4% in native breeds of Chinese birds, in contrast with 0% in WL1 and 6.8% in WL2. The carrier frequency of ALVE9 was 0.1% in the Chinese indigenous population, and was 16.0% in WL1 and 11.9% in WL2. The carrier frequency of ALVE21 was 10.4% in Chinese chickens, whereas ALVE21 was detected with a frequency of 0% in WL1 and 50% in WL2. The frequency of the TVB resistance allele (TVB*R and TVB*R') was 0.4% in Beijing You chickens, whereas it was 70.5% in WL1 and 54.5% in WL2. No carriers of ALVE3, ALVE9, and ALVE21 were detected in Silkie fowl, a famous Chinese native breed that has been used as a source for alternative medicine. These results present molecular evidence of ALVE3, ALVE6, ALVE9, and ALVE21 insertions and TVB genotypes in Chinese indigenous chickens and could provide potential molecular insights into anti-ALV breeding in chickens.

Anti-Asthma Simplified Herbal Medicine Intervention-induced long-lasting tolerance to allergen exposure in an asthma model is interferon-γ, but not transforming growth factor-β dependent

BACKGROUND

Chronic allergic asthma is the result of a T-helper type 2 (Th2)-biased immune status. Current asthma therapies control symptoms in some patients, but a long-lasting therapy has not been established. Anti-Asthma Simplified Herbal Medicine Intervention (ASHMI™), a Chinese herbal formula, improved symptoms and lung function, and reduced Th2 responses in a controlled trial of patients with persistent moderate to severe asthma.

OBJECTIVE

We evaluated the persistence of ASHMI™ beneficial effects following therapy in a murine model of chronic asthma and the immunological mechanisms underlying such effects. Methods BALB/c mice sensitized intraperitoneally with ovalbumin (OVA) received 3 weekly intratracheal OVA challenges to induce airway hyper-reactivity (AHR) and inflammation (OVA mice). Additionally, OVA mice were treated with ASHMI™ (OVA/ASHMI™) or water (OVA/sham) for 4 weeks, and then challenged immediately and 8 weeks post-therapy. In other experiments, OVA mice received ASHMI™ treatment with concomitant neutralization of IFN-γ or TGF-β. Effects on airway responses, cytokine- and OVA-specific IgE levels were determined 8 weeks post-therapy.

RESULTS

Before treatment, OVA mice exhibited AHR and pulmonary eosinophilic inflammation following OVA challenge, which was almost completely resolved immediately after completing treatment with ASHMI™ and did not re-occur following OVA re-challenge up to 8 weeks post-therapy. Decreased allergen-specific IgE and Th2 cytokine levels, and increased IFN-γ levels also persisted at least 8 weeks post-therapy. ASHMI™ effects were eliminated by the neutralization of IFN-γ, but not TGF-β, during therapy.

CONCLUSION

ASHMI™ induced long-lasting post-therapy tolerance to antigen-induced inflammation and AHR. IFN-γ is a critical factor in ASHMI™ effects.

Comparison Between Cadmium Zinc Telluride Crystals Grown in Russia and in the Ukraine

A comparative analysis of different Cd1−xZnxTe (CZT) crystals grown by a vertical high pressure Bridgman (VHPB) method is reported. The results of several analytical techniques, such as triple axis x-ray diffraction (TAD), rocking curves, low temperature photoluminescence (PL), scanning electron microscopy (SEM), and proton induced x-ray emission (PIXE) are discussed. Segregated carbon inclusions were identified by SEM and energy dispersive x-ray fluorescence (EDXRF), and the results are interpreted in terms of constitutional supercooling of the solidifying CZT melt. The carbon inclusions significantly decrease the resistivity, and in some cases, the noise is too large for the fabrication of radiation detectors. Combining these results with other measurements reported by our research team [1], we identify correlations between the growth and the defects identified in these CZT crystals.

Isolation and characterization of twelve polymorphic microsatellite loci in the buff-throated partridge (Tetraophasis szechenyii)

Twelve polymorphic microsatellite markers were isolated from an AC-enriched genomic library of Buff-throated partridge (Tetraophasis szechenyii). The allele number of these loci ranged from three to 13 (average 7.75 per locus) in tested individuals. Polymorphism information content ranged from 0.532 to 0.882 with an average of 0.721. Average observed and expected heterozygosities were 0.559 (range from 0.240 to 0.792) and 0.772 (range from 0.621 to 0.910), respectively. These microsatellite markers will be useful for the assessment of genetic diversity, relatedness identification of family and analysis of population structure in wild buff-throated partridge.

Adenosine 2A receptor is protective against renal injury in MRL/lpr mice

OBJECTIVE

Adenosine is considered as a potent endogenous anti-inflammatory and immunosuppressive molecule. We examined the roles of A2A-adenosine receptor (A(2A)R) in the progression of lupus nephritis.

METHODS

MRL/lpr mice were given a selective A(2A)R agonist, CGS21680 (0.4 mg/kg per day, i.p.) while control mice received saline only. After 8 weeks of treatment, mice were sacrificed for assessment of functional and histological parameters as well as inflammatory infiltration in the kidneys. MCP-1, IFN-γ, MHC-II and A(2A)R mRNA expression was evaluated by RT-PCR. Expression of A(2A)R and nuclear NFκB p65 protein was determined by Western blot analysis. Levels of anti-dsDNA antibody and IFN-γ were measured by ELISA.

RESULTS

CGS21680 treatment resulted in significant decrease in proteinuria, blood urea and creatinine as well as improvement in renal histology. Renal macrophage and T-cell infiltration were significantly attenuated in association with suppressed expression of MCP-1, IFN-γ and MHC-II. CGS21680 treatment reduced the level of serum anti-dsDNA and renal immune complex deposition. CGS21680 inhibited the activation of NFκB and suppressed the expression of IFN-γ, MCP-1 and MHC-II in MRL/lpr splenocytes.

CONCLUSIONS

A(2A)R activation suppressed inflammation in the kidneys of MRL/lpr mice and can be considered as a novel therapeutic approach for human lupus nephritis.

Effect of myofiber characteristics and thickness of perimysium and endomysium on meat tenderness of chickens

The objective of the present study was to evaluate the role of myofiber characteristics and the thickness of 2 major muscle membranes, perimysium and endomysium, in determining the breast meat tenderness of chickens. Birds from 2 breeds (White Leghorn and a line of broiler) were chosen. Chicks were sexed and wing-banded at hatch and were grown in separate cages in a single house. Sixty broilers and 60 White Leghorns were harvested at 6 wk of age, respectively, whereas another 60 White Leghorns were slaughtered at 18 wk of age. An equal number of males and females was maintained for each group. Body weight, breast muscle weight, pH, drip loss, cooking loss, Warner-Bratzler shear force value (SFV), total energy of shear force, fiber diameter, sarcomere length, myofiber density, and the thickness of endomysium and perimysium of the breast were determined for each bird. At 6 wk of age, histological examination indicated that the size of myofiber and thickness of endomysium and perimysium of broilers were larger than that those of White Leghorns (P < 0.01), whereas the SFV, drip loss, and cooking loss of broilers were smaller (P < 0.01). A comparison between the White Leghorns at 18 wk and the broilers at 6 wk, which were at similar BW but different ages, showed that the breast muscle weight of broilers was larger (P < 0.01) than that of White Leghorns. For breast muscle, the endomysium of broilers at 6 wk was thicker than that of White Leghorns at 18 wk (P < 0.01), whereas the perimysium was thinner (P < 0.01). The SFV, drip loss, and the cooking loss of broilers were smaller than those of White Leghorns at similar BW (P < 0.01). Meat tenderness was negatively correlated with myofiber density (-0.27) and the thickness of endomysium (-0.29) and positively correlated with the thickness of perimysium (0.20). It is suggested that muscle membrane should be considered in evaluating meat tenderness of the chicken.

Part 5. Public health and air pollution in Asia (PAPA): a combined analysis of four studies of air pollution and mortality

BACKGROUND

In recent years, Asia has experienced rapid economic growth and a deteriorating environment caused by the increasing use of fossil fuels. Although the deleterious effects of air pollution from fossil-fuel combustion have been demonstrated in many Western nations, few comparable studies have been conducted in Asia. Time-series studies of daily mortality in Asian cities can contribute important new information to the existing body of knowledge about air pollution and health. Not only can these studies verify important health effects of air pollution in local regions in Asia, they can also help determine the relevance of existing air pollution studies to mortality and morbidity for policymaking and environmental controls. In addition, the studies can help identify factors that might modify associations between air pollution and health effects in various populations and environmental conditions. Collaborative multicity studies in Asia-especially when designed, conducted, and analyzed using a common protocol-will provide more robust air pollution effect estimates for the region as well as relevant, supportable estimates of local adverse health effects needed by environmental and public-health policymakers.

SPECIFIC OBJECTIVES

The Public Health and Air Pollution in Asia (PAPA*) project, sponsored by the Health Effects Institute, consisted of four studies designed to assess the effects of air pollution on mortality in four large Asian cities, namely Bangkok, in Thailand, and Hong Kong, Shanghai, and Wuhan, in China. In the PAPA project, a Common Protocol was developed based on methods developed and tested in NMMAPS, APHEA, and time-series studies in the literature to help ensure that the four studies could be compared with each other and with previous studies by following an established protocol. The Common Protocol (found at the end of this volume) is a set of prescriptive instructions developed for the studies and used by the investigators in each city. It is flexible enough to allow for adjustments in methods to optimize the fit of health-effects models to each city's data set. It provides the basis for generating reproducible results in each city and for meta-estimates from combined data. By establishing a common methodology, factors that might influence the differences in results from previous studies can more easily be explored. Administrative support was provided to ensure that the highest quality data were used in the analysis. It is anticipated that the PAPA results will contribute to the international scientific discussion of how to conduct and interpret time-series studies of air pollution and will stimulate the development of high-quality routine systems for recording daily deaths and hospital admissions for time-series analysis.

METHODS

Mortality data were retrieved from routine databases with underlying causes of death coded using the World Health Organization (WHO) International Classification of Diseases, 9th revision or 10th revision (ICD-9, ICD-10). Air quality measurements included nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter < or = 10 microm (PM10), and ozone (O3) and were obtained from several fixed-site air monitoring stations that were located throughout the metropolitan areas of the four cities and that met the standards of procedures for quality assurance and quality control carried out by local government units in each city. Using the Common Protocol, an optimized core model was established for each city to assess the effects of each of the four air pollutants on daily mortality using generalized linear modeling with adjustments for time trend, seasonality, and other time-varying covariates by means of a natural-spline smoothing function. The models were adjusted to suit local situations by correcting for influenza activity, autocorrelation, and special weather conditions. Researchers in Hong Kong, for example, used influenza activity based on frequency of respiratory mortality; researchers in Hong Kong and Shanghai used autoregressive terms for daily outcomes at lag days; and researchers in Wuhan used additional smoothing for periods with extreme weather conditions.

RESULTS AND DISCUSSION

For mortality due to all natural (nonaccidental) causes at all ages, the effects of air pollutants per 10-microg/m3 increase in concentration was found to be higher in Bangkok than in the three Chinese cities, with the exception of the effect of NO2 in Wuhan. The magnitude of the effects for cardiovascular and respiratory mortality were generally higher than for all natural mortality at all ages. In addition, the effects associated with PM10 and O3 in all natural, cardiovascular; and respiratory mortality were found to be higher in Bangkok than in the three Chinese cities. The explanation for these three findings might be related to consistently higher daily mean temperatures in Bangkok, variations in average time spent outdoors by the susceptible populations, and the fact that less air conditioning is available and used in Bangkok than in the other cities. However, when pollutant concentrations were incorporated into the excess risk estimates through the use of interquartile range (IQR), the excess risk was more comparable across the four cities. We found that the increases in effects among older age groups were greater in Bangkok than in the other three cities. After excluding data on extremely high concentrations of PM10 in Bangkok, the effect estimate associated with PM10 concentrations decreased in Bangkok (suggesting a convex relationship between risk and PM10, where risk levels off at high concentrations) instead of increasing, as it did in the other cities. This leveling off of effect estimates at high concentrations might be related to differences in vulnerability and exposure of the population to air pollution as well as to the sources of the air pollutant. IMPLICATIONS OF THE STUDY: The PAPA project is the first coordinated Asian multicity air pollution study ever published; this signifies the beginning of an era of cooperation and collaboration in Asia, with the development of a common protocol for coordination, data management, and analysis. The results of the study demonstrated that air pollution in Asia is a significant public health burden, especially given the high concentrations of pollutants and high-density populations in major cities. When compared with the effect estimates reported in the research literature of North America and Western Europe, the study's effect estimates for PM10 were generally similar and the effect estimates for gaseous pollutants were relatively higher. In Bangkok, however, a tropical city where total exposures to outdoor pollution might be higher than in most other cities, the observed effects were greater than those reported in the previous (i.e., Western) studies. In general, the results suggested that, even though social and environmental conditions across Asia might vary, it is still generally appropriate to apply to Asia the effect estimates for other health outcomes from previous studies in the West. The results also strongly support the adoption of the global air quality guidelines recently announced by WHO.

Developmental phenotypic-genotypic associations of tyrosinase and melanocortin 1 receptor genes with changing profiles in chicken plumage pigmentation

The tyrosinase (TYR) and melanocortin 1 receptor (MC1R) genes have been accepted as major genes involved in the plumage pigmentation of chickens. The co-segregation of plumage coloration and sequence polymorphism in TYR and MC1R genes were investigated using an intercross between black and white plumage color types of the Dongxiang blue-shelled chicken. Profiles of plumage color changing and genes expression levels of TYR and MC1R were observed from hatch to 112 d of age using quantitative real-time reverse transcription-PCR. Intercrossed offspring were classified by phenotypes of plumage colors. The phenotypes of black and amber chicks with genotypes of E_C_ exhibited a black feather pattern, whereas white, gray, and buff chicks with genotypes of E_cc and eecc belonged to the white feather pattern. Although TYR in cooperation with MC1R determined the coloration feather patterns, the different phenotypes did not correspond completely with the genotypes. During the period studied, plumage phenotype changed dramatically, and the buff and gray down were gradually replaced by whiteness feathers. Real-time reverse transcription-PCR studies showed that 1) expression levels of TYR declined dramatically with age, and expression at hatch was highest (P<0.01) during the ages studied; 2) expression level of MC1R was higher at 28 d than at younger and older ages; and 3) expression of TYR in chickens carrying E/E and E/e alleles on MC1R loci were higher than those carrying e/e alleles from hatch to 28 d.

Low-density lipoprotein receptor-related protein 8 gene association with egg traits in dwarf chickens

Low-density lipoprotein receptor-related protein 8 (LRP8), a member of the low-density lipoprotein receptor gene family with a role in clusterin processing, was investigated as a candidate gene for egg quality-related traits. One SNP from C to T at position 1623 of the open reading frame of LRP8 was identified and genotyped by a high-throughput genotyping method, matrix-assisted laser desorption-ionization time-of-flight mass spectrometry in 747 egg-type dwarf layers from 44 sire families. There were no significant differences among genotypes for any interior egg traits measured, except for yolk color, in which color was deeper for the TT genotype than CC or CT (P < 0.05). For shell traits, strength and thickness were greater for TT than CC (P < 0.05), with CT intermediate and not different from either. Shape index was lower for CT than either TT or CC, which did not differ, whereas for shell color, CT was intermediate to the homozygotes, which differed (CC > TT). The present results indicated that LRP8, as a new member of eggshell matrix protein, may be a candidate gene associated with eggshell traits.

Jak/STAT signaling is involved in the inflammatory infiltration of the kidneys in MRL/lpr mice

Cytokines are known to play an important role in the pathogenesis of lupus nephritis (LN) and the Jak/STAT (Janus kinase-signal transducer and activator of transcription factor) pathway is important in mediating signal transduction of cytokines. This study examined the pathogenic role of Jak/STAT signaling in LN. MRL/lpr mice were either treated with a selective Jak2 inhibitor tyrphostin AG490 or with vehicle alone from 12 weeks of age until being sacrificed at week 20. AG490 significantly inhibited the phosphorylation of Jak2 and STAT1 (p < 0.05). Compared with the vehicle-treated mice, AG490 treatment significantly reduced proteinuria, improved renal function and suppressed histological lesions of the kidneys and salivary glands (p < 0.05). AG490 treatment significantly inhibited the renal expression of monocyte chemotactic protein (MCP)-1, interferon (IFN)-gamma and class II MHC, which was accompanied by reduced renal infiltration of T cells and macrophages (p < 0.05). In addition, AG490 treatment resulted in a decrease in serum anti-double-stranded DNA (anti-dsDNA) antibody and attenuated the deposition of IgG and C3 in the kidneys (p < 0.05). This study demonstrated that Jak/STAT pathway is implicated in the progression of renal inflammation in MRL/lpr mice and targeting this pathway may provide a potential therapeutic approach for LN.

Activation of submucosal 5-HT(3) receptors elicits a somatostatin-dependent inhibition of ion secretion in rat colon

BACKGROUND AND PURPOSE

5-Hydroxytryptamine (5-HT) is a key regulator of the gastrointestinal system and we have shown that submucosal neuronal 5-HT(3) receptors exerted a novel inhibitory effect on colonic ion transport. The aim of the present study was to investigate the precise mechanism(s) underlying this inhibitory effect.

EXPERIMENTAL APPROACH

Mucosa/submucosa or mucosa-only preparations from rat distal colon were mounted in Ussing chambers for measurement of short-circuit current (I(sc)) as an indicator of ion secretion. Somatostatin release was determined with radioimmunoassay. Intracellular cAMP content was measured with enzyme-linked immunoadsorbent assay (elisa). Immunohistochemical techniques were used to study the expression of 5-HT(3) receptors, somatostatin and somatostatin receptors in colonic tissue.

KEY RESULTS

In rat distal colonic mucosa/submucosa preparations, pretreatment with 5-HT(3) receptor antagonists enhanced 5-HT-induced increases in I(sc). However, in mucosa-only preparations without retained neural elements, pretreatment with 5-HT(3) receptor antagonists inhibited 5-HT-induced DeltaI(sc). Pretreatment with a somatostatin-2 (sst(2)) receptor antagonist in mucosa/submucosa preparations augmented 5-HT-induced DeltaI(sc). Combination of sst(2) and 5-HT(3) receptor antagonists did not cause further enhancement of 5-HT-induced DeltaI(sc). Moreover, both sst(2) and 5-HT(3) receptor antagonists enhanced 5-HT-induced increase in intracellular cAMP concentration in the mucosa/submucosa preparations. 5-HT released somatostatin from rat colonic mucosa/submucosa preparations, an effect prevented by pretreatment with 5-HT(3) receptor antagonists. Immunohistochemical staining demonstrated the presence of 5-HT(3) receptors on submucosal somatostatin neurons and of sst(2) receptors on colonic mucosa.

CONCLUSION AND IMPLICATIONS

Activation of neuronal 5-HT(3) receptors in the submucosal plexus of rat colon suppressed 5-HT-induced ion secretion by releasing somatostatin from submucosal neurons.

Monitoring of CaSO(4) deposition behaviors on biofilm during nanofiltration via ultrasonic time-domain reflectometry (UTDR)

The ultrasonic time-domain reflectometry (UTDR) as a non-destructive real-time method was employed to monitor the CaSO(4) deposition behaviors on biofilm during nanofiltration (NF). Two parallel experiments were performed to compare the different behaviors of CaSO(4) deposition with and without biofilm on the membrane. Results showed that the flux decline during combined fouling was slower than that in case of CaSO(4) fouling alone. The Ca(2 + ) rejection obtained with biofilm was higher than that without. A larger acoustic differential signal obtained by UTDR in the combined fouling revealed a denser and thicker layer formed on the membrane surface. Furthermore, the amount of CaSO(4) deposition on the biofouled membrane was more than that on non-biofouled membrane as a result of microorganisms as crystal nucleus to induce CaSO(4) crystallization and deposition. SEM images indicate that the CaSO(4) crystals deposited in order on the non-biofouled membrane, whereas on the biofouled membrane they were embedded in the biofilm. The denser and thicker fouling layer formed with biofilm was impermeable, resulting in a high Ca(2 + ) rejection. The complexation of Ca with polysaccharide in biofilm would eliminate the cake-enhanced osmotic pressure effect leading to a slow flux decline. To sum up, the independent measurements corroborate the ultrasonic measurements.

Evaluation of stem cell differentiation in diabetic rats transplanted with bone marrow mesenchymal stem cells

OBJECTIVE

Bone marrow mesenchymal stem cell (BM-MSC) transplantation has generated a great deal of excitement as a promising therapeutic strategy for diabetes mellitus. However, the exact mechanisms of reversing hyperglycemia remain elusive. Our objective was to investigate whether stem cell differentiation determined therapeutic efficacy.

MATERIALS AND METHODS

Wistar rats were rendered diabetic by an intraperitoneal injection of streptozotocin. BM-MSCs isolated from diabetic Wistar rats were analyzed for phenotype characteristics. Subsequently, BM-MSCs were transplanted into diabetic rats, followed by intravenous injection of recombinant lentiviruses encoding 2 different small hairpin RNAs (shRNAs) for specific interference with neurogenin 3 (Ngn3). We measured blood glucose levels and insulin and performed histological analysis of the pancreas.

RESULTS

BM-MSCs lowered blood glucose by increasing beta-cell mass compared with sham-operated controls, but this effect was inhibited by interference with the Ngn3 gene.

CONCLUSION

Differentiation of stem cells, including BM-MSCs and endogenous pancreatic stem cells, plays a major role in the process of reversing hyperglycemia.

A curved image-plate detector system for high-resolution synchrotron X-ray diffraction

The developed curved image plate (CIP) is a one-dimensional detector which simultaneously records high-resolution X-ray diffraction (XRD) patterns over a 38.7 degrees 2theta range. In addition, an on-site reader enables rapid extraction, transfer and storage of X-ray intensity information in </=30 s, and further qualifies this detector to study kinetic processes in materials science. The CIP detector can detect and store X-ray intensity information linearly proportional to the incident photon flux over a dynamical range of about five orders of magnitude. The linearity and uniformity of the CIP detector response is not compromised in the unsaturated regions of the image plate, regardless of saturation in another region. The speed of XRD data acquisition together with excellent resolution afforded by the CIP detector is unique and opens up wide possibilities in materials research accessible through X-ray diffraction. This article presents details of the basic features, operation and performance of the CIP detector along with some examples of applications, including high-temperature XRD.