[Effect of family with sequence similarity 13 member A gene interference on apoptosis and proliferation of human airway epithelial cells and its relationship with small airway remodeling in patients with chronic obstructive pulmonary disease].

Objective: To explore the relationship between family with sequence similarity 13 member A (FAM13A) gene and small airway remodeling in chronic obstructive pulmonary disease (COPD), and the effect of interference with FAM13A gene expression on the apoptosis and proliferation phenotype of human airway epithelial cells (16HBE). Methods: From January 2018 to January 2020, 74 patients in the Department of Thoracic Surgery of General Hospital of Ningxia Medical University were treated by surgery for lung tumors or pulmonary bullae. According to the lung function and smoking history, the 74 patients were divided into four groups: non-smoking group with normal lung function (normal group, 23 patients), smoking group with normal lung function (smoking group, 24 patients), non-smoking group with COPD (11 patients) and smoking group with COPD (16 patients). The expression of FAM13A in small airway of each group was detected by immunohistochemistry, and the correlation between FAM13A and the airflow restriction indexes by pulmonary function was analyzed. The shRNA fragment of FAM13A gene was designed, and the shRNA lentivirus vector of FAM13A gene was constructed and packaged. The expression level of FAM13A gene was detected by real-time fluorescent quantitative PCR (qRT-PCR) and Western blot, and the best shRNA sequence was screened. Flow cytometry was used to detect apoptosis rate and the fluorescence intensity of proliferation marker Ki-67 in 16HBE cells. Results: FAM13A was mainly expressed in the cytoplasm of small airway epithelial cells. The levels of FAM13A absorbance (A) of small airway epithelial cells in non-smoking group and smoking group with COPD were higher than those in normal group and smoking group (0.365±0.026, 0.412±0.053 to 0.113±0.018, 0.105±0.009, all P<0.05), and they were negatively correlated with forced expiratory volume in 1s/forced vital capacity (FEV(1)/FVC) and FEV(1)% pre (r=-0.48 and r=-0.40, all P<0.05). The FAM13A shRNA lentiviral vector was successfully constructed, and FAM13A interference was successfully achieved in the 16HBE cell line. After infection of 16HBE cells, the results of qRT-PCR and Western blot showed that the expression of FAM13A in shRNA-target-2 group decreased (all P<0.01). Compared with the negative control group (shRNA-NC), the apoptosis rate of FAM13A shRNA group decreased (P=0.023), and the fluorescence intensity of Ki-67 also decreased (P=0.042). Conclusions: FAM13A gene expression is increased in COPD small airway epithelial cells, and it is related to COPD airflow limitation. FAM13A gene may participate in the process of COPD remodeling by affecting the apoptosis and proliferation of human airway epithelial cells.

Ipriflavone reverses the adverse effects of a low-calcium diet on the histology of the tibia in caged layers.

1. Ipriflavone (IP) has been widely studied in humans and is effective for inhibiting osteoclastic bone resorption and enhancing osteoblastic bone formation. The aim of this study was to investigate the effects of IP on the structural histology and histomorphometric parameters of tibia in laying hens fed on a low-calcium diet. 2. A total of 200 Hy-Line Brown laying hens, 24 weeks of age, were divided randomly into 4 groups which were fed on one of 4 diets (CaN, standard diet; CaL, low-calcium diet; IP1, low-calcium diet + 8 mg/kg of IP; IP2, low-calcium diet + 20 mg/kg of IP) for 60 d after which 10 hens of each group, chosen at random, were killed and the tibiae were processed and assessed under a fluorescent microscope 3. The cortical bone showing resorption cavities had become porous, and medullary bone did not completely fill the marrow cavity in the CaL group compared with the CaN group. However, in the IP2 group, the cortical bone showed a structure comparable to the CaN group with an absence of resorption cavities, and more medullary bone filled the marrow cavity compared with the CaL group. 4. The CaL hens had significantly lower trabecular bone area, trabecular perimeter, per cent trabecular area, trabecular number and trabecular thickness and significantly wider trabecular separation compared with CaN. These results indicated that the low-calcium diet led to increased loss of tibial bone, eventually causing osteoporosis. However, compared with the CaL group, the IP2 group caused a significant increase in trabecular bone area and bone quality. 5. It is concluded that even in hens fed on a low-calcium diet, the addition of 20 mg/kg IP exerted beneficial effects on histological structure and structural histomorphometric parameters of tibia, indicating an alleviation of caged layer osteoporosis (CLO).

Leptin regulated calcium channels of neuropeptide Y and proopiomelanocortin neurons by activation of different signal pathways.

The fat-derived hormone leptin regulates food intake and body weight in part by modulating the activity of neuropeptide Y (NPY) and proopiomelanocortin (POMC) neurons in the hypothalamic arcuate nucleus (ARC). To investigate the electrophysiological activity of these neurons and their responses to leptin, we recorded whole-cell calcium currents on NPY and POMC neurons in the ARC of rats, which we identified by morphologic features and immunocytochemical identification at the end of recording. Leptin decreased the peak amplitude of high voltage-activated calcium currents (I(HVA)) in the isolated neurons from ARC, which were subsequently shown to be immunoreactive for NPY. The inhibition was prevented by pretreatment with inhibitors of Janus kinase 2 (JAK2) and mitogen-activated protein kinases (MAPK). In contrast, leptin increased the amplitude of I(HVA) in POMC-containing neurons. The stimulations of I(HVA) were inhibited by blockers of JAK2 and phosphatidylino 3-kinase (PI3-k). Both of these effects were counteracted by the L-type calcium channel antagonist nifedipine, suggesting that L-type calcium channels were involved in the regulation induced by leptin. These data indicated that leptin exerted opposite effects on these two classes of neurons. Leptin directly inhibited I(HVA) in NPY neurons via leptin receptor (LEPR) -JAK2-MAPK pathways, whereas evoked I(HVA) in POMC neurons by LEPR-JAK2-PI3-k pathways. These neural pathways and intracellular signaling mechanisms may play key roles in regulating NPY and POMC neuron activity, anorectic action of leptin and, thereby, feeding.

Effects of overexpression of endogenous phenylalanine ammonia-lyase (PALrs1) on accumulation of salidroside in Rhodiola sachalinensis.

Salidroside, a novel effective adaptogenic drug extracted from the medicinal plant Rhodiola sachalinensis A. Bor, can be derived from phenylalanine or tyrosine. Due to the scarcity of R. sachalinensis and its low yield of salidroside, there is great interest in enhancing production of salidroside by the plant. In this study, a cDNA clone encoding phenylalanine ammonia-lyase (PAL) was isolated from R. sachalinensis using rapid amplification of cDNA ends. The resulting cDNA was designated PALrs1. It is 2407-bp long and encodes 710 deduced amino acid residues. Southern blot analysis of genomic DNA indicated that the PAL gene family is composed of three to five genes in the R. sachalinensis genome. Northern blot analysis revealed that transcripts of PALrs1 were present in calli, leaves and stems, but expression in roots was very low. The PALrs1 under the 35S promoter with double-enhancer sequences from CaMV-Omega and TMV-Omega fragments was transferred into R. sachalinensis via Agrobacterium tumefaciens. PCR and PCR-Southern blot confirmed that the PALrs1 gene had been integrated into the genome of transgenic plants. Northern blot analysis revealed that the PALrs1 gene had been expressed at the transcriptional level. High-performance liquid chromatography indicated that overexpression of the PALrs1 gene resulted in a 3.3-fold increase in p-coumaric acid content, as expected. In contrast, levels of tyrosol and salidroside were 4.7-fold and 7.7-fold, respectively, lower in PALrs1 transgenic plants than in controls. Furthermore, overexpression of the PALrs1 gene resulted in a 2.6-fold decrease in tyrosine content. These data suggest that overexpression of the PALrs1 gene and accumulation of p-coumaric acid did not facilitate tyrosol biosynthesis; tyrosol, as a phenylethanoid derivative, is not derived from phenylalanine; and reduced availability of tyrosine most likely resulted in a large reduction in tyrosol biosynthesis and accumulation of salidroside.

Granulocyte colony-stimulating factor improves neurological function and angiogenesis in intracerebral hemorrhage rats.

OBJECTIVE: Granulocyte colony-stimulating factor (G-CSF) plays a role in regulating phosphatidylinositol-3-kinase/serine/threonine kinase (PI3K/AKT) pathway, affecting cell proliferation and apoptosis, and inducing vascular endothelial growth factor (VEGF) expression. This study investigated the mechanism of G-CSF on angiogenesis and neural protection after intracerebral hemorrhage (ICH). MATERIALS AND METHODS: The rats were divided into four groups, including sham, ICH, ICH+G-CSF, and ICH+G-CSF+LY294002 (PI3K/AKT signaling pathway specific inhibitor). Cerebral neurological dysfunction was tested by Garcia scoring. Cell apoptosis was detected by transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assay. Angiogenesis marker CD34 expression, PI3K/AKT signaling pathway, B-cell lymphoma-2 (Bcl-2), and VEGF expressions were compared by IHC. Rat cerebral nerve RN-c cells were divided into four groups, including control, oxygen-glucose deprivation (OGD), OGD+G-CSF, and OGD+G-CSF+LY294002. RESULTS: Neurological dysfunction was more evident; CD34+ cell number, VEGF expression, and cell apoptosis significantly increased; phosphorylated AKT (p-AKT) and Bcl-2 levels markedly reduced in ICH group compared with sham group. G-CSF apparently up-regulated p-AKT and Bcl-2 expressions, attenuated cell apoptosis, and elevated CD34+ cell number. LY294002 significantly decreased p-AKT, Bcl-2, and VEGF expressions, and alleviated the cell apoptosis protective and angiogenesis effect induced by G-CSF. OGD treatment induced RN-c cell apoptosis, down-regulated p-AKT and Bcl-2 expressions, and enhanced the tube capacity of vascular endothelial cells (VEC). G-CSF markedly elevated p-AKT and Bcl-2 contents in RN-c cells, declined cell apoptosis, increased p-AKT and VEGF levels in VEC, and enhanced tube capacity. CONCLUSIONS: G-CSF enhanced PI3K/AKT signaling pathway activity, promoted Bcl-2 and VEGF expression, reduced nerve cell apoptosis, and enhanced tube capacity of VECs, which may be the mechanism of G-CSF in improving neurological function and angiogenesis after ICH.

Research on biogenesis of mitochondria in astrocytes in sepsis-associated encephalopathy models.

OBJECTIVE: To study the structural and functional changes in mitochondria in astrocytes of the cerebral cortex of the rats in the simulated sepsis environment in vitro and the relationship between these changes and the biogenesis of mitochondria in astrocytes by establishing models of sepsis astrocytes. MATERIALS AND METHODS: The structural and functional changes in mitochondria in astrocytes of the cerebral cortex of the rats were evaluated. The ultra structural changes in the mitochondria, astrocytes, and ultrathin sections, were observed with a transmission electron microscope. The expression of the regulatory factors related to biogenesis of mitochondria in astrocytes of the cerebral cortex of the rats was evaluated in various experimental groups. RT-PCR and Western blot were used to evaluate the expression of the regulatory factors related to biogenesis of mitochondria in astrocytes of the cerebral cortex of the rats. The "point grid method" was used to evaluate the volume density of the mitochondria in the astrocytes of the cerebral cortex of the rats in various experimental groups. The Western blotting was used to evaluate the role of fusion and fission of mitochondria in the astrocytes of the cerebral cortex of the rats in various experimental groups in regulating the expression of the protein-OPAI and DRPI. RESULTS: In the sepsis astrocyte models established by co-incubation of LPS and IFN-γ and astrocytes of the cerebral cortex of the rats, the mitochondria with a minor injury in the 6 h group (2.97± 0.92) increased significantly when compared with those in the 0 h group (1.08±0.95), 12 h group (1.70±1.01), and 24 h group (1.59±0.55) (p<0.05); the concentration of adenosine triphosphate (ATP) in the astrocytes of the cerebral cortex of the rats in the 6 h, 12 h, and 24 h groups increased significantly when compared with that in the 0 h group (p<0.05). PGC-1α mRNA, NRF-1 mRNA, NRF-2α mRNA, NRF-2ß mRNA, and mitochondrial transcription factor A (TFAM) mRNA in the astrocytes of the cerebral cortex of the rats in the 6 h and 12 h groups increased significantly when compared with those in the 0 h group (p<0.05); the concentration of TFAM mRNA (1.20±0.19) increased significantly when compared with that in the 0 h group (p<0.05). The OPAI protein concentration (1.21±0.17:1.34±0.06) and DRPI protein concentration (1.04±0.05; 1.05±0.05) in the astrocytes of the cerebral cortex of the rats in the 12 h group (1.25±0.17), 24 h group (1.33±0.24), and 6 h group increased significantly when compared with that in the 0 h group (p <0.05). CONCLUSIONS: The experimental sepsis conditions can cause a minor injury of the ultrastructure of the mitochondria in the astrocytes of the cerebral cortex of the rats. The biogenesis of the mitochondria in the astrocytes of the cerebral cortex of the rats was strengthened to cater for the increased demand for energy of the astrocytes under the sepsis conditions and finally recover the ultrastructure of the mitochondria with a minor injury. In response to the increased mitochondrial biogenesis, the activities of the mitochondrial fusion and fission of the astrocytes of the cerebral cortex of the rats were increased.

Xuebijing injection treatment inhibits vasopermeability and reduces fluid requirements in a canine burn model.

OBJECTIVE: High vasopermeability and excessive inflammation following severe burns may result in tissue edema, organ dysfunction and the loss of circulatory plasma volume, which can influence the doctor to do the prognosis to the patients. The study aims to examine whether Xuebijing injection (XBJ), an extracts of a traditional Chinese medicine used to treat sepsis in clinic, can reduces fluid requirements by inhibiting vasopermeability and tissue edema in a canine model after burn injury. METHODS: Twenty-four beagle dogs were subjected to 50% TBSA burns, and then were randomly allocated to the following three groups: lactated Ringer's resuscitation (LR) group (n = 8), immediate LR containing Xuebijing injection (LR/XBJ) group (n = 8), and operation control group (n = 8). Hemodynamic variables and net fluid accumulation were measured. Blood samples were collected for measurement of hematocrit and circulatory plasma volume (PV). At 24 h after burn injury, heart, lung, small intestine and kidney were harvested for evaluation of the activities of myeloperoxidase (MPO) and neutrophil elastase (NE), vasopermeability, tissue water content and the amount of neutrophil infiltration. RESULTS: XBJ treatment significantly reduced net fluid accumulation, and pulmonary vascular permeability index (PVPI), extravascular lung water index (ELWI), and water content of heart, small intestine, kidney and lung compared with LR group. Furthermore, XBJ infusion significantly reduced tissue activities of MPO and NE compared with LR group. The amount of neutrophil infiltration in LR/XBJ group was lower than that in LR group. CONCLUSIONS: These results indicate that XBJ injection can reduce fluid requirements by inhibition of neutrophil protease-induced high vasopermeability and tissue edema.

Characterization of aqueous lead removal by phosphatic clay: equilibrium and kinetic studies.

Immobilization of heavy metals from contaminated environments is an emerging field of interest from both resource conservation and environmental remediation points of view. This study investigated the feasibility of using phosphatic clay, a waste by-product of the phosphate mining industry, as an effective sorbent for Pb from aqueous effluents. The major parameters controlling aqueous Pb removal, viz. initial metal ion concentrations, solution pH, sorbent amounts, ionic strength and presence of both inorganic and organic ligands were evaluated using batch experiments. Results demonstrated that aqueous Pb removal efficiency of phosphatic clay is controlled mainly by dissolution of phosphatic clay associated fluoroapatite [Ca(10)(PO(4))(5)CaCO(3)(F,Cl,OH)(2)], followed by subsequent precipitation of geochemically stable pyromorphite [Pb(10)(PO(4))(6)(F,Cl,OH)(2)], which was confirmed by both X-ray diffraction (XRD) and scanning electron microscopic (SEM) analysis. Lead removal efficiency of phosphatic clay increased with increasing pH, sorbent amount and decreasing ionic strength. It also depends on the nature of complexing ligands. Formation of insoluble calcium oxalate and lead oxalate in the presence of oxalic acid explained high uptake of Pb by phosphatic clay from aqueous solution. However, Pb sorption kinetics onto phosphatic clay were biphasic, with initially fast reactions followed by slow and continuous Pb removal reactions. The slow reactions may include surface sorption, co-precipitation and diffusion. The exceptional capability of phosphatic clay to remove aqueous Pb demonstrated its potential as a cost effective way to remediate Pb-contaminated water, soils and sediments.

A natural food sweetener with anti-pancreatic cancer properties.

Mogroside V is a triterpenoid isolated from the traditional Chinese medical plant Siraitia grosvenorii. Mogroside V has a high degree of sweetness and a low calorific content. Herein, we found that mogroside V possesses tumor growth inhibitory activity in in vitro and in vivo models of pancreatic cancer by promoting apoptosis and cell cycle arrest of pancreatic cancer cells (PANC-1 cells), which may in part be mediated through regulating the STAT3 signaling pathway. These results were confirmed in vivo in a mouse xenograft model of pancreatic cancer. In xenograft tumors, Ki-67 and PCNA, the most commonly used markers of tumor cell proliferation, were downregulated after intravenous administration of mogroside V. Terminal deoxynucleotidyl transferase dUTP nick end labeling assays showed that mogroside V treatment promoted apoptosis of pancreatic cancer cells in the xenograft tumors. Furthermore, we found that mogroside V treatment significantly reduced the expression of CD31-labeled blood vessels and of the pro-angiogenic factor vascular endothelial growth factor in the xenografts, indicating that mogroside V might limit the growth of pancreatic tumors by inhibiting angiogenesis and reducing vascular density. These results therefore demonstrate that the natural, sweet-tasting compound mogroside V can inhibit proliferation and survival of pancreatic cancer cells via targeting multiple biological targets.

Potential arsenic exposures in 25 species of zoo animals living in CCA-wood enclosures.

Animal enclosures are often constructed from wood treated with the pesticide chromated copper arsenate (CCA), which leaches arsenic (As) into adjacent soil during normal weathering. This study evaluated potential pathways of As exposure in 25 species of zoo animals living in CCA-wood enclosures. We analyzed As speciation in complete animal foods, dislodgeable As from CCA-wood, and As levels in enclosure soils, as well as As levels in biomarkers of 9 species of crocodilians (eggs), 4 species of birds (feathers), 1 primate species (hair), and 1 porcupine species (quills). Elevated soil As in samples from 17 enclosures was observed at 1.0-110mg/kg, and enclosures housing threatened and endangered species had As levels higher than USEPA's risk-based Eco-SSL for birds and mammals of 43 and 46mg/kg. Wipe samples of CCA-wood on which primates sit had dislodgeable As residues of 4.6-111µg/100cm(2), typical of unsealed CCA-wood. Inorganic As doses from animal foods were estimated at 0.22-7.8µg/kg bw/d. Some As levels in bird feathers and crocodilian eggs were higher than prior studies on wild species. However, hair from marmosets had 6.37mg/kg As, 30-fold greater than the reference value, possibly due to their inability to methylate inorganic As. Our data suggested that elevated As in soils and dislodgeable As from CCA-wood could be important sources of As exposure for zoo animals.

Simulation of phytoremediation of a TNT-contaminated soil using the CTSPAC model.

Knowledge of water movement in the plant-xylem system and contaminant bioavailability in the soil environment is crucial to evaluate the success of phytoremediation practices. This study investigated the removal of 2,4,6-trinitrotoluene (TNT) from a contaminated sandy soil by a single poplar (Populus fastigiata) tree through the examinations of temporal variations of xylem water potential, root water uptake, and soil TNT bioavailability. A mathematical model, CTSPAC (Coupled Transport of water, heat, and solutes in the Soil-Plant-Atmosphere Continuum), was modified for the purpose of this study. The model was calibrated using laboratory measurements before its application. Our simulations show that the xylem water potential was high in the roots and low in the leaves with a potential head difference of 3.55 cm H2O, which created a driving force for water flow and chemical transport upward from the roots through the stem to the leaves. The daily average root water uptake rate was 25 cm3 h(-1) when an equilibrium condition was reached after 24 h. Our simulations further reveal that no TNT was found in the stem and leaves and only about 1% of total TNT mass was observed in the roots due to the rapid biodegradation and transformation of TNT into its daughter products. About 13% of the soil TNT was removed by the poplar tree, resulting mainly from root uptake since TNT is a recalcitrant compound. In general, the soil TNT bioavailability decreased with time due to the depletion of soil solution TNT by the poplar tree. A constant bioavailability (i.e., 3.1 x 10(-6)) was obtained in 14 d in which the soil TNT concentration was about 10 mg L(-1). Our study suggests that CTSPAC is a useful model to simulate phytoremediation of TNT-contaminated sites.

Arsenic bioaccessibility in contaminated soils: Coupling in vitro assays with sequential and HNO3 extraction.

Arsenic bioaccessibility varies with in vitro methods and soils. Four assays including unified BARGE method (UBM), Solubility Bioaccessibility Research Consortium method (SBRC), in vitro gastrointestinal method (IVG), and physiologically based extraction test (PBET), were used to determine As bioaccessibility in 11 contaminated soils (22-4,172 mg kg(-1)). The objective was to understand how bioaccessible As by different methods was related to different As pools based on sequential extraction and 0.43 M HNO3 extraction. Arsenic bioaccessibility was 7.6-25, 2.3-49, 7.3-44, and 1.3-38% in gastric phase (GP), and 5.7-53, 0.46-33, 2.3-42, and 0.86-43% in intestinal phase (IP) for UBM, SBRC, IVG, and PBET, respectively, with HNO3-extractable As being 0.90-60%. Based on sequential extraction, As was primarily associated with amorphous (AF3; 17-79%) and crystallized Fe/Al oxides (CF4; 6.4-73%) while non-specifically sorbed (NS1), specifically sorbed (SS2), and residual fractions (RS5) were 0-10%, 3.4-20% and 3.2-25%. Significant correlation was found between As bioaccessibility by PBET and NS1+SS2 (R(2) = 0.55-0.69), and UBM-GP and NS1 + SS2 + AF3 (R(2) = 0.58), indicating PBET mostly targeted As in NS1+SS2 whereas UBM in NS1 + SS2 + AF3. HNO3-extractable As was correlated to bioaccessible As by four methods (R(2) = 0.42-0.72) with SBRC-GP having the best correlation. The fact that different methods targeted different As fractions in soils suggested the importance of validation by animal test. Our data suggested that HNO3 may have potential to determine bioaccessible As in soils.

Cleaning-induced arsenic mobilization and chromium oxidation from CCA-wood deck: Potential risk to children.

Concern about children's exposure to arsenic (As) from wood treated with chromated-copper-arsenate (CCA) led to its withdrawal from residential use in 2004. However, due to its effectiveness, millions of American homes still have CCA-wood decks on which children play. This study evaluated the effects of three deck-cleaning methods on formation of dislodgeable As and hexavalent chromium (CrVI) on CCA-wood surfaces and in leachate. Initial wipes from CCA-wood wetted with water showed 3-4 times more dislodgeable As than on dry wood. After cleaning with a bleach solution, 9.8-40.3µg/100cm(2) of CrVI was found on the wood surface, with up to 170µg/L CrVI in the leachate. Depending on the cleaning method, 699-2473mg of As would be released into the environment from cleaning a 18.6-m(2)-deck. Estimated As doses in children aged 1-6 after 1h of playing on a wet CCA-wood deck were 0.25-0.41µg/kg. This is the first study to identify increased dislodgeable As on wet CCA-wood and to evaluate dislodgeable CrVI after bleach application. Our data suggest that As and CrVI in 25-year old CCA-wood still show exposure risks for children and potential for soil contamination.

In vitro bioaccessibility and in vivo relative bioavailability in 12 contaminated soils: Method comparison and method development.

Previous studies have established in vivo-in vitro correlations (IVIVC) between arsenic (As) relative bioavailability (RBA) and bioaccessibility in contaminated soils. However, their ability to predict As-RBA in soils outside the models is unclear. In this study, As bioaccessibility and As-RBA in 12 As-contaminated soils (22.2-4172 mg kg(-1) As) were measured using five assays (SBRC, IVG, DIN, PBET, and UBM) and a mouse blood model. Arsenic RBA in the soils ranged from 6.38 ± 2.80% to 73.1 ± 17.7% with soils containing higher extractable Fe showing lower values. Arsenic bioaccessibility varied within and between assays. Arsenic bioaccessibility was used as input values into established IVIVC to predict As-RBA in soils. There were significant differences between predicted and measured As-RBA for the 12 soils, illustrating the inability of established IVIVC to predict As-RBA in those contaminated soils. Therefore, a new IVIVC was established by correlating measured As-RBA and As bioaccessibility for the 12 soils. The strength of the predictive models varied from r(2) = 0.50 for PBET to r(2) = 0.83 for IVG, with IVG assay providing the best prediction of As-RBA. When IVIVC were compared to those of Juhasz et al. (2014a), slopes of the relationships were significantly higher possibly due to different As-RBA measurements. Our research showed that IVG has potential to measure As bioavailability in contaminated soils from China though UBM and SBRC assays were also suitable. More research is needed to verify their suitability to predict As-RBA in soils for refining health risk assessment.

Magnetic resonance imaging for the evaluation of a novel metastatic orthotopic model of human neuroblastoma in immunodeficient mice.

Neuroblastoma is the second most common solid tumor in children. So far few tumor models for this cancer have been reported in mice. We have created a murine tumor model for studying human neuroblastoma based on surgical orthotopic implantation in scid mice. Small fragments of subcutaneous tumors of SK-N-BE(2) human neuroblastoma cells expressing enhanced green fluorescent protein were surgically implanted near the left adrenal gland of scid mice. One hundred percent of the animals (n = 21) successfully implanted developed a large retroperitoneal tumor and became moribund between 22 and 57 days after implantation (mean survival time = 41 days). At the time of sacrifice the presence of bone marrow metastasis was detected by RT-PCR for green fluorescent protein in 95% of the cases. The growth of small tumor implants could be easily visualized and quantified by surveillance MR imaging, with a resolution of 117 x 117 x 750 microm in two orthogonal planes allowing accurate volume measurements, as well as assessment of necrosis and tissue invasion. This novel model should be a valuable tool to study the biology and therapeutic approaches to neuroblastoma.

Relation of enhanced Pb solubility to Fe partitioning in soils.

It is well documented that Pb solubility may be related to Fe chemistry in soils and enhanced Pb solubility may occur under certain reducing conditions; however, quantification of such relationships is unavailable. Based on metal classification, Pb (II) and Fe (II) are similar in some chemical characteristics. Thus, competition between Pb and Fe for ligands in soils may be important in determining Pb solubility. In this paper, Pb solubility was examined in a sandy soil after spiking with Pb and incubating for 40 days under water-flooded or non-water-flooded conditions. Solution chemistry in soil columns was adjusted using different concentrations of NaCl, CaCl(2) and deionized water of varying pH before incubation. The results showed that Pb solubility in the soil was not correlated well with pH, dissolved organic C or aqueous Fe concentrations. However, an index of Fe partition behavior using the ratio of aqueous Fe to sorbed Fe was related to Pb solubility. Enhanced Pb solubility occurred only when the index was < approximately 2 kg l(-1). The index can be a simple measure of Fe's ability to compete with Pb for ligands in solution. The ability of Fe to compete with Pb decreases as the index decreases and as the ratio approached its minimum, substantial increases in Pb solubility will be expected. In general, the index was not sensitive to changes in solution chemistry. A similar trend was observed using one data set published in the literature.

Cu, Cr and As distribution in soils adjacent to pressure-treated decks, fences and poles.

Chromated copper arsenate (CCA)-treated wood has been widely used in the Southeastern United States to protect wood products from microbial and fungal decay. The aims of this study were to (1). determine the distribution of arsenic (As), chromium (Cr), and copper (Cu), in soils surrounding CCA-treated wood structures such as decks, fences and poles; and (2). evaluate the impacts of these structures on As, Cr and Cu loading of the soils. Profile and lateral soil samples were collected under CCA-treated decks and adjacent to poles and fences. The results showed elevation of As, Cr and Cu concentrations close to and under the structures, with mean As concentrations as high as 23 mg x kg(-1) close to utility poles compared with less than 3 mg x kg (-1) at distances of about 1.5 m away. Concentrations of As, Cr, and Cu decreased with depth in areas close to CCA-treated poles. However, these results were only apparent in relatively new structures. A combination of weathering and leaching with time may have reduced the impact in older poles. Increased concentrations of As, Cu and Cr were also observed close to CCA-treated decks and fences, with age showing a similar impact. These results are helpful for CCA-treated wood product users to determine the safe use of these structures.

Effects of sample storage on biosolids compost stability and maturity evaluation.

Compost stability and maturity are important parameters of compost quality. To date, nearly all compost characterization has been performed using samples freshly collected because sample storage can affect compost stability and maturity evaluation. However, sample preservation is sometimes necessary, especially for scientific research purposes. There is little information available on the effects of sample storage on compost stability and maturity. Samples of biosolids compost with different levels of stability and maturity were collected from four compost facilities in Florida (referred to as Register, Winslow, Sunset, and Meadow). Comparisons of CO2 evolution, seed germination rate, and water-soluble organic carbon (WSOC) were made between fresh samples with short storage at 4 degrees C for less than 1 wk and air-dried or frozen compost samples stored for 1 yr. The effects of storage (air-dry or frozen) on the measured parameters depended on compost stability and maturity and on the compost material source. Frozen storage reduced the peak CO2 evolution of Register samples by 12 to 29%, while accumulated CO2 evolution was reduced by 43 to 64% and 110 to 277% with air-dry and frozen storage, respectively. The storage effect on CO2 evolution with more stable compost was inconsistent. Storage did not affect compost phytotoxicity, except for samples from the Sunset facility. Air-drying reduced the WSOC by up to 35%, and freezing increased it by up to 34%, while both storage methods had no significant effect on samples of low WSOC. Despite all these variations, WSOC had a significant and consistent relation to CO2 evolution and seed germination rates with R2 of 0.78 and 0.57, respectively, regardless of storage methods.

Relationship between compost stability and extractable organic carbon.

Establishing a simple yet reliable compost stability test is essential for a better compost quality control and utilization efficiency. The objective of this study was to examine the relationship between extractable organic carbon (OC) and compost stability based on 18 compost samples from five composting facilities. The compost samples were extracted sequentially with water for 2 h [water(2h)] and 0.1 M NaOH for 2 and 24 h [NaOH(2h) and NaOH(24h), respectively]. The extractable OC was further separated into fulvic acid (FA) and humic acid (HA) fractions by adjusting the pH to <2. The mass specific absorbance (MSA) of OC in the six fractions was measured. Compost stability was estimated with a CO2 evolution method. The extractable OC concentration was influenced by the total volatile solids and decreased with curing time for compost with a high level of extractable OC. The OC levels in each fraction were significantly correlated (p < 0.05) to each other except for the water(2h)-extractable HA. In addition, all the FA and HA fractions except for water(2h)-extractable HA were highly (P < 0.01) and linearly correlated to CO2 evolution, but multiple regression showed that NaOH(24h)-extractable OC was insignificant for CO2 evolution. The relatively high slope of NaOH(2h)-extractable FA versus CO2 evolution suggests that this fraction may contribute the most to compost CO2 evolution. The water(2h)- and/or NaOH(2h)-extractable FA tests are recommended for measuring compost stability because of their high correlation with CO2 evolution. This estimation can be obtained through a simple photometric method covering a wide range of carbon concentrations up to 4,000 mg L(-1).