In vitro and in vivo testing of novel ultrathin PCL and PCL/PLA blend films as peripheral nerve conduit

In an attempt to obviate the drawbacks of nerve autograft, ultrathin microporous biodegradable PCL and PCL/PLA films were tested for their compatibility with motor neuron-like NG108-15 cells and primary Schwann cells. Data obtained from MTS colorimetric and DNA fluorimetric assays showed that both cell lines readily attached and proliferated on these materials. Images taken using scanning electron microscope and fluorescence microscope confirmed these observations. Enhanced cell-surface interaction was achieved by pretreating the films in NaOH solution. Importantly, NG108-15 cells could be induced into differentiated phenotype with long, un-branched neurites growing across the surface of the materials. The bipolar spindle-shaped phenotype of Schwann cells was also retained on these scaffolds. Positive immunochemical staining using antibodies against neurofilament for NG108-15 cells and S100 for Schwann cells indicated the expression of these marker proteins. In a small-scaled pilot testing, the performance of PCL conduits in bridging up a 10 mm gap in rat sciatic nerve model was assessed. Immunohistochemical staining showed that regenerated nerve tissue and penetrated Schwann cells have the potential to span the whole length of the conduit in 2 weeks.

[Effects of glutamine on platelet-derived growth factor and its receptor following septic brain damage in rats]

OBJECTIVE

This study investigated the expression of platelet-derived growth factor-B (PDGF-B) and its receptor-β (PDGFR-β) in rat cerebral cortex following sepsis and explored the possible underlying mechanism of neuro-protective effect of glutamine (Gln).

METHODS

One hundred and twenty 10-day-old Wistar rats were randomly divided into three groups: a control group that received an intraperitoneal injection of normal saline (1 mL/kg), a sepsis group that received an intraperitoneal injection of lipopolysaccharide (LPS, 5 mg/kg), and a Gln treatment group that was administered with Gln (1.346 g/kg) 1 hr before LPS injection. The rats were subdivided into 5 groups sacrificed at 2, 6, 12, 24 and 72 hrs after LPS or normal saline injection (n=8). The distribution and expression of PDGF-B and PDGFR-β in the cerebral cortex were ascertained by immunohistochemistry and Western blot.

RESULTS

The immunohistochemistry results showed that the PDGF-B and PDGFR-β expression in the cerebral cortex increased significantly in the Gln treatment group 72 hrs after LPS injection compared with that in the control and the sepsis groups. The Western blot results showed that the PDGF-B expression in the brain tissue in the sepsis and the Gln treatment groups were significantly lower than that in the control group 2, 6, and 12 hrs after LPS injection, while the Gln treatment group had increased PDGF-B expression compared with the sepsis group 12 and 72 hrs after LPS injection. Compared with the control group, the PDGFR-β expression in the brain tissue in the sepsis group increased 2 and 6 hrs after LPS injection but decreased significantly 72 hrs after LPS injection. There were no significant differences in the PDGFR-β expression between the Gln treatment and the control groups at all different time points.

CONCLUSIONS

Gln can increase the PDGF-B and PDGFR-β expression in the brain tissue of rats with sepsis. The increased PDGF-B and PDGFR-β expression might contribute to neuro-protective effects of Gln.

Redox control and hydrogen production in sediment caps using carbon cloth electrodes

Sediment caps that degrade contaminants can improve their ability to contain contaminants relative to sand and sorbent-amended caps, but few methods to enhance contaminant degradation in sediment caps are available. The objective of this study was to determine if, carbon electrodes emplaced within a sediment cap at poised potential could create a redox gradient and provide electron donor for the potential degradation of contaminants. In a simulated sediment cap overlying sediment from the Anacostia River (Washington, DC), electrochemically induced redox gradients were developed within 3 days and maintained over the period of the test (∼100 days). Hydrogen and oxygen were produced by water electrolysis at the electrode surfaces and may serve as electron donor and acceptor for contaminant degradation. Electrochemical and geochemical factors that may influence hydrogen production were studied. Hydrogen production displayed zero order kinetics with ∼75% Coulombic efficiency. Rates were proportional to the applied potential between 2.5 and 5 V and not greatly affected by pH. Hydrogen production was promoted by increasing ionic strength and in the presence of natural organic matter. Carbon electrode-stimulated degradation of tetrachlorobenzene in a batch reactor was dependent on applied voltage and production of hydrogen to a concentration above the threshold for biological dechlorination. These findings suggest that electrochemical reactive capping can potentially be used to create "reactive" sediments caps capable of promoting chemical or biological transformations of contaminants within the cap.

Improved scatter correction using adaptive scatter kernel superposition

Accurate scatter correction is required to produce high-quality reconstructions of x-ray cone-beam computed tomography (CBCT) scans. This paper describes new scatter kernel superposition (SKS) algorithms for deconvolving scatter from projection data. The algorithms are designed to improve upon the conventional approach whose accuracy is limited by the use of symmetric kernels that characterize the scatter properties of uniform slabs. To model scatter transport in more realistic objects, nonstationary kernels, whose shapes adapt to local thickness variations in the projection data, are proposed. Two methods are introduced: (1) adaptive scatter kernel superposition (ASKS) requiring spatial domain convolutions and (2) fast adaptive scatter kernel superposition (fASKS) where, through a linearity approximation, convolution is efficiently performed in Fourier space. The conventional SKS algorithm, ASKS, and fASKS, were tested with Monte Carlo simulations and with phantom data acquired on a table-top CBCT system matching the Varian On-Board Imager (OBI). All three models accounted for scatter point-spread broadening due to object thickening, object edge effects, detector scatter properties and an anti-scatter grid. Hounsfield unit (HU) errors in reconstructions of a large pelvis phantom with a measured maximum scatter-to-primary ratio over 200% were reduced from -90 ± 58 HU (mean ± standard deviation) with no scatter correction to 53 ± 82 HU with SKS, to 19 ± 25 HU with fASKS and to 13 ± 21 HU with ASKS. HU accuracies and measured contrast were similarly improved in reconstructions of a body-sized elliptical Catphan phantom. The results show that the adaptive SKS methods offer significant advantages over the conventional scatter deconvolution technique.

Microstructure and photoluminescence studies of Sb-doped SnO2 zigzag nanobelts

SnO2 zigzag nanobelts were successfully Sb-doped by a simple vapor deposition method. Field emission scanning electron microscope (FESEM), high resolution transmission electron microscope (HRTEM), and X-ray diffraction (XRD) were used to characterize these Sb-doped nanobelts. The Sb doping in SnO2 nanobelts was confirmed by Energy Dispersive X-ray spectrum (EDS) and X-ray photoelectron spectroscopy (XPS). It is found that there is no apparent lattice distance difference between the pure SnO2 and the 0.705 at% Sb doped SnO2 nanobelts. A slight blue-shift in the photoluminescence (PL) spectra was shown with the increase of Sb doping concentration and a reasonable explanation was given.

Simian virus 40 inhibits differentiation and maturation of rhesus macaque DC-SIGN(+) dendritic cells

Dendritic cells (DC) are the initiators and modulators of the immune responses. Some species of pathogenic microorganisms have developed immune evasion strategies by controlling antigen presentation function of DC. Simian virus 40 (SV40) is a DNA tumor virus of rhesus monkey origin. It can induce cell transformation and tumorigenesis in many vertebrate species, but often causes no visible effects and persists as a latent infection in rhesus monkeys under natural conditions. To investigate the interaction between SV40 and rhesus monkey DC, rhesus monkey peripheral blood monocyte-derived DC were induced using recombinant human Interleukin-4 (rhIL-4) and infective SV40, the phenotype and function of DC-specific intracellular adhesion molecule-3 grabbing nonintegrin (DC-SIGN)(+) DC were analyzed by flow cytometry (FCM) and mixed lymphocyte reaction (MLR). Results showed that SV40 can down-regulate the expression of CD83 and CD86 on DC and impair DC-induced activation of T cell proliferation. These findings suggest that SV40 might also cause immune suppression by influencing differentiation and maturation of DC.

[Characteristics of glucose metabolism in non-obese and obese women with polycystic ovarian syndrome]

OBJECTIVE

To investigate characteristics of glucose metabolism of non-obese and obese women with polycystic ovary syndrome (PCOS).

METHODS

From May 2006 to April 2009, 1928 PCOS patients treated in Reproductive Medicine Center of Shandong Provincial Hospital Affiliated to Shandong University were enrolled in this study, which were divided into 901 cases [body mass index (BMI) ≥ 25 kg/m²] in obese group and 1027 cases in non-obese (BMI < 25 kg/m(2)) group. The prevalence of type 2 diabetes mellitus (T2DM), oral glucose tolerance test, impaired fasting glucose (IFG), impaired glucose tolerance (IGT) were compared between the two groups.

RESULTS

(1) Blood glucose levels: at the time of fasting, 30, 60, 120 and 180 minutes, the levels of glucose were (5.3 ± 1.1), (9.0 ± 2.4), (9.3 ± 4.4), (7.5 ± 2.8), (5.3 ± 1.8) mmol/L in obese group and (5.0 ± 0.8), (8.4 ± 3.5), (8.0 ± 4.2), (6.5 ± 3.2), (4.9 ± 1.6) mmol/L in non-obese group, which all showed statistical difference at every time point (P < 0.01). (2)The level of insulin: at the time of fasting, 30, 60, 120 min, the level of insulin were (13 ± 7), (81 ± 51), (102 ± 65), (83 ± 63) mU/L in obese group and (8 ± 5), (57 ± 35), (62 ± 44), (46 ± 39) mU/L in non-obese group, which all showed statistical difference at every time point (P < 0.01). However, at time point of 180 minutes, the level of insulin did not exhibit significantly difference between obese and non-obese group (P > 0.05). (3) The prevalence of abnormal glucose metabolism: the rate of IFG was 4.98% (96/1928). The rate of abnormal glucose tolerance was 23.08% (445/1928). The rate of IGT were 13.05% (134/1027) in non-obese group and 24.20% (218/901) in obese group, which also showed remarkable difference (P < 0.01). The rate of T2DM were 2.53% (26/1027) in non-obese group and 7.44% (67/901) in obese group, which reached significant difference (P < 0.01).

CONCLUSION

Abnormal glucose metabolism was observed more frequently in overweight or obese PCOS women.

Genetic diversity and population structure of a diverse set of rice germplasm for association mapping

Germplasm diversity is the mainstay for crop improvement and genetic dissection of complex traits. Understanding genetic diversity, population structure, and the level and distribution of linkage disequilibrium (LD) in target populations is of great importance and a prerequisite for association mapping. In this study, 100 genome-wide simple sequence repeat (SSR) markers were used to assess genetic diversity, population structure, and LD of 416 rice accessions including landraces, cultivars and breeding lines collected mostly in China. A model-based population structure analysis divided the rice materials into seven subpopulations. 63% of the SSR pairs in these accessions were in LD, which was mostly due to an overall population structure, since the number of locus pairs in LD was reduced sharply within each subpopulation, with the SSR pairs in LD ranging from 5.9 to 22.9%. Among those SSR pairs showing significant LD, the intrachromosomal LD had an average of 25-50 cM in different subpopulations. Analysis of the phenotypic diversity of 25 traits showed that the population structure accounted for an average of 22.4% of phenotypic variation. An example association mapping for starch quality traits using both the candidate gene mapping and genome-wide mapping strategies based on the estimated population structure was conducted. Candidate gene mapping confirmed that the Wx and starch synthase IIa (SSIIa) genes could be identified as strongly associated with apparent amylose content (AAC) and pasting temperature (PT), respectively. More importantly, we revealed that the Wx gene was also strongly associated with PT. In addition to the major genes, we found five and seven SSRs were associated with AAC and PT, respectively, some of which have not been detected in previous linkage mapping studies. The results suggested that the population may be useful for the genome-wide marker-trait association mapping. This new association population has the potential to identify quantitative trait loci (QTL) with small effects, which will aid in dissecting complex traits and in exploiting the rich diversity present in rice germplasm.

Relationship between TLR2 and TLR4 mRNA expression and LPS-induced intestinal injury in rats

AIM: To determine the relationship between Toll-like receptors 2 and 4 (TLR2 and TLR4) mRNA expression and lipopolysaccharide (LPS)-induced intestinal injury in rats.

METHODS: Fifty-six Wistar rat pups aged 10 d were randomly divided into control group (normal saline 1 mL/kg, ip, n = 8) and LPS group (LPS 5 mg/kg, ip, n = 48). The rats in the control group were sacrificed 3 h after treatment, while those in the LPS group were sacrificed at 3, 6, 12, 24, 48 and 72 h after injection of LPS. The intestinal tissue was dissected for histopathologic analysis. The expression of TLR2 and 4 mRNAs in intestinal tissue was detected by RT-PCR.

RESULTS: The expression of TLR2 mRNA was weak in the intestine of rats in the control group, while TLR4 mRNA was highly expressed in the intestine of rats in the control group. The expression of TLR2 mRNA was markedly increased at 3 and 6 h (4.068 ± 0.86 and 5.314 ± 1.82 vs 1.390 ± 0.04, both P < 0.01) after intraperitoneal injection of LPS, peaking at 72 h (10.401 ± 1.73 vs 1.390 ± 0.04, P < 0.01). TLR4 mRNA expression was significantly increased at 3 h (16.711 ± 1.28 vs 9.907 ± 0.33, P < 0.01) after intraperitoneal LPS injection, but markedly decreased at 72 h (7.055 ± 1.27 vs 9.907 ± 0.33).

CONCLUSION: TLR2 and TLR4 mRNA expression is related with LPS-induced intestinal injury in rats.