Protective role of Shenfu on ischemia-reperfusion injury of rat liver grafts

AIMS

We sought to investigate the protective role of Shenfu (SF),a traditional Chinese formulation comprising Radix Ginseng and Radix Aconitum Carmichaeli on ischemia-reperfusion injury in rat liver grafts.

METHODS

Ninety-six male Sprague Dawley rats were used as donors (n = 48) and recipients (n = 48) of orthotopic liver transplantation. They were randomly divided into a control group with donor livers injected with saline through the portal vein immediately after recovery versus the SF group, with livers injected with SF. Each group was further divided into 3 subgroups equally to obtain bood and hepatic tissues samples at 2, 4, and 6 hours reperfusion.

RESULTS

At each phase, the SF group, showed significantly higher bile production (P < .05) with lower serum levels of alanine aminotransferase and tumor necrosis factor-α, and nuclear factor-κB expression in the hepatic tissues. (P < .05). SF group hepatic tissues showed less injury compared with controls.

CONCLUSION

SF injection seemed to protect hepatocytes from injury during the early reperfusion phase and to improve subsequent rat liver graft function.

Norepinephrine stimulates pancreatic cancer cell proliferation, migration and invasion via β-adrenergic receptor-dependent activation of P38/MAPK pathway

BACKGROUND/AIMS

There is growing evidence that chronic stress is associated with cancer pathogenesis and progression, but the mechanisms involved in this association are poorly understood. This study aims to examine the effect of stress hormone norepinephrine (NE) on proliferation, migration and invasion of human pancreatic cancer cells and the molecular pathway involved.

METHODOLOGY

PANC-1 cells were examined for the expression of β-Adrenergic receptor (β-AR) subtypes, β1-AR, β2-AR by RT-PCR and western blotting, respectively. The PANC-1 cells proliferation, cell cycle distribution, cell migration and invasion were assessed by CCK-8, flow cytometry, scratch wound healing and transwell Matrigel, respectively.

RESULTS

PANC- 1 cells expressed both β1-AR and β2-AR protein. Exposure of PANC-1 cells to increasing concentrations of NE stimulated cell proliferation in a dose-dependent fashion. In addition, NE increased S-phase population and decreased G1 and G2-phase population of PANC- 1 cells. Furthermore, NE significantly enhanced migration and invasion of PANC-1 cells. More strikingly, we observed that NE elevated P38/MAPK phosphorylation (Phos-p38) level. These stimulatory effects were completely abolished by β-AR antagonist propranolol (PRO) or P38/MAPK inhibitor SB203580.

CONCLUSIONS

NE could stimulate pancreatic cancer cell proliferation, migration and invasion through a β-AR-dependent activation of P38/MAPK pathway involved.

Determining the mechanisms for aerobic granulation from mixed seed of floccular and crushed granules in activated sludge wastewater treatment

Aerobic granulation is a novel and promising technology for wastewater treatment. However, long start-up periods required for the development of granules from floccular sludge, and the loss of biomass in this period leading to poor nutrient removal performance are key challenges. In a recent study the addition of crushed granules to a floccular sludge significantly reduced the start-up period, and also maintained the nutrient removal performance during granulation. In this study, we examined the mechanisms responsible for the fast granulation from a mixture of floccular and granular sludges. Fluorescent microbead particles (4 μm diameter) were successfully applied to differentially label the surfaces of floccular and crushed granular aggregates. Labelled flocs and crushed granules were added to a laboratory scale wastewater treatment reactor, and the granule formation process was monitored using confocal laser scanning microscopy over an 80 day period. Flocs were observed to attach to the surface of the seeding granules, resulting in reduced biomass washout during granulation. This mechanism not only reduces the granulation period, but also maintains the nutrient removal performance of the reactor. The results indicate that the granules acted as nuclei for floccular particle attachment, which accelerated granule formation.

Emergence of resistance to fluoroquinolones and third-generation cephalosporins in Shigella flexneri subserotype 1c isolates from China

We report here on the first identification of Shigella flexneri subserotype 1c in China. We also report the emergence of resistance to ciprofloxacin and third-generation cephalosporins in this subserotype 1c for the first time. Isolates of seven strains circulating in China yielded three new sequence types and seven pulsed-field gel electrophoresis patterns, thus demonstrating the existence of high genetic diversity within the isolates. Overall, the seven isolates showed reduced susceptibility to ciprofloxacin; one isolate was ciprofloxacin resistant, whilst another developed resistance to ciprofloxacin, norfloxacin, cefotaxime and ceftriaxone.

Integrated modelling of sewer system and wastewater treatment plant for investigating the impacts of chemical dosing in sewers

Chemicals are often dosed to control the production and accumulation of hydrogen sulfide in sewers. The biological and/or chemical actions of these chemicals have profound impacts on the composition of wastewater entering a WWTP, thereby affecting its performance. In this paper, an integrated modelling methodology for simultaneously investigating the effects of dosing of chemicals in sewer network and N and P removal at the downstream WWTP is reported. The sewer system is modelled using a sewer model (SeweX), and the WWTP is modelled using ASM2d model with some modifications. The importance of integrated modelling in sewer management is also demonstrated.

Towards a benchmarking tool for minimizing wastewater utility greenhouse gas footprints

A benchmark simulation model, which includes a wastewater treatment plant (WWTP)-wide model and a rising main sewer model, is proposed for testing mitigation strategies to reduce the system's greenhouse gas (GHG) emissions. The sewer model was run to predict methane emissions, and its output was used as the WWTP model input. An activated sludge model for GHG (ASMG) was used to describe nitrous oxide (N(2)O) generation and release in activated sludge process. N(2)O production through both heterotrophic and autotrophic pathways was included. Other GHG emissions were estimated using empirical relationships. Different scenarios were evaluated comparing GHG emissions, effluent quality and energy consumption. Aeration control played a clear role in N(2)O emissions, through concentrations and distributions of dissolved oxygen (DO) along the length of the bioreactor. The average value of N(2)O emission under dynamic influent cannot be simulated by a steady-state model subjected to a similar influent quality, stressing the importance of dynamic simulation and control. As the GHG models have yet to be validated, these results carry a degree of uncertainty; however, they fulfilled the objective of this study, i.e. to demonstrate the potential of a dynamic system-wide modelling and benchmarking approach for balancing water quality, operational costs and GHG emissions.

Enhancing aerobic granulation for biological nutrient removal from domestic wastewater

This study focuses on the enhancement of aerobic granulation and biological nutrient removal maintenance treating domestic wastewater. Two sequencing batch reactors (SBRs) were inoculated with either only floccular sludge (100%-floc SBR) or supplemented with 10% crushed granules (90%-floc SBR). Granules developed in both reactors. The 100%-floc SBR achieved 75% of nitrogen and 93% of phosphorus removal at the end of the performance, but some floccular sludge remained in the system. The 90%-floc SBR became fully granulated and finished with 84% and 99% of nitrogen and phosphorus removal, respectively. Regarding biological phosphorus removal, nitrite was identified as an inhibitor of the process. Nitrite levels lower than 5 mg N-NO2-L(-1) were used for anoxic phosphate uptake while higher concentrations inhibited the process.

Molecular level dynamics of genetic oscillator--the effect of protein-protein interaction

Uncovering how interactions of a set of molecular components influence the system's dynamic behavior is important for understanding intracellular processes and elucidating design principles, but unfortunately, there are limited efforts for studying this issue. Here, we study the effect of distinct post-translational dynamics controlled by protein dimerization on oscillations in the repressilator. For this, we propose three biologically motivated model scenarios of the repressilator with monomer or dimer being the active form of repressor, and with protein-protein interactions. It is found that the dimer dissociation constant can tune oscillatory regions, frequency and amplitude. Introducing a modified linear noise approximation to evaluate fluctuations of amplitude and period in the oscillatory systems, we show that different dimerization leads to a different effect on period and amplitude in reducing noise. The manipulation of the circuit's biochemical properties provides a practical strategy for designing a robust and tunable oscillator.

A novel p53-based strategy for protection of gastrointestinal track and bone marrow (BM) from 5-fluorouracil (5-FU)

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Background: Acute toxicity from DNA damaging agents such as radiation and chemotherapy is mainly mediated by p53 which, upon activation, induces massive apoptotic cell death in sensitive tissues such as GI track and BM. Expanding from our recent finding that low-dose arsenic can temporarily and reversibly suppress p53 activation and subsequent tissue damages in normal tissues but not in carcinomas due to distinct differences in p53 status, we used a mouse tumor xenograft model to test the potential of arsenic in protecting the GI track and BM from one of the most commonly used chemotherapeutic agents for GI malignancies, 5-FU, without compromising tumor control.

Methods: Arsenic pretreatment was done by feeding sex-matched mice (4-6 weeks old) with water with or without 1.0 mg/L sodium arsenic for 3 days. Mice were randomized into 4 groups: A. control; B. arsenic only; C. 5-FU (30 mg/kg body weight i.v. for 5 days) only; D. arsenic and 5-FU. 5- FU-induced GI track and BM damages were analyzed histologically with H&E staining 4 weeks after last treatment. Body weight was monitored as a measure of toxicity. Lung carcinoma NCI-H358 was used to generate a mouse xenograft model. Treatments were initiated 3 weeks after implantation when the lung carcinomas reached an average volume of 100 mm3. Tumor volumes were measured periodically. Two independent experiments were done with10 mice per group.

Results: Tumor sizes at 9 weeks were (mean±SE in mm3): 528.1±62.81, 504.04±55.19, 133.02±35.74, 114.47±17.49 for groups A,B,C and D respectively (p=ns, C vs. D). The corresponding body weights were (in gm): 34.6±1.5, 36.4±2.1, 31±1.2, and 35.4±1.8 (p=0.0001, t-test, C vs D). 5-FU treatment was associated with severe damages to small intestine and BM, and such damages were significantly reduced by low-dose arsenic pretreatment by histological examination.

Conclusions: Our data demonstrate that a brief treatment with low-dose arsenic is associated with a marked protection of GI track and BM without compromising the ability of 5-FU to kill carcinoma cells.Our data have provided proof-of- principle for the use of low-dose arsenic to protect GI track and BM from toxicity of 5-FU, and for potential 5-FU dose intensification in clinical settings.

No significant financial relationships to disclose.

Simultaneous determination of lincomycin and spectinomycin residues in animal tissues by gas chromatography-nitrogen phosphorus detection and gas chromatography-mass spectrometry with accelerated solvent extraction

A new multi-dimensional analytical method using gas chromatography-nitrogen phosphorus detection (GC-NPD) and gas chromatography-mass spectrometry (GC-MS) was developed for qualitative and quantitative measurement of lincomycin and spectinomycin residues in food animal tissues. This method is based on a new extraction procedure using accelerated solvent extraction (ASE). The analytes were extracted by phosphate buffer with trichloroacetic acid deproteinization and clean-up by C₁₈ solid-phase extraction (SPE) adding dodecanesulfonic acid sodium salt as an ion-pair reagent. The eluted fraction was evaporated and derivatised with N,O-bis(trimethylsilyl) trifluoroacetamide (BSTFA) for GC-NPD analysis and GC-MS confirmation. Parameters for extraction pressure, temperature and cycle of ASE, clean-up, derivatisation and analysis procedure were optimised. The method was validated in muscle, kidney and liver of swine, bovine with a low concentration (limit of quantification) of 16.4 and 21.4 µg kg⁻¹ for these two analytes using GC-NPD. For GC-MS, the limits of quantification were 4.1 and 5.6 µg kg⁻¹, respectively. Spiked recoveries from levels of 20 to 200 µg kg⁻¹ were found to be between 73% and 99% with a relative standard deviation (RSD) of less than 17% in GC-NPD. For GC-MS, levels from 5 to 20 µg kg⁻¹ had between 70% and 93% with an RSD of less than 21%. This rapid and reliable method can be used for the characterisation and quantification of residues of lincomycin and spectinomycin in animal tissues.

Pioglitazone modulates the balance of effector and regulatory T cells in apolipoprotein E deficient mice

BACKGROUND AND AIMS

Pioglitazone (PIO) affects T cell-mediated immunity through actions of peroxisome proliferator activated receptor γ (PPARγ). Effector and regulatory T cells control the development of atherosclerosis, a chronic inflammatory disease affecting the arterial blood vessels. The aim of this study was to examine whether PIO ameliorates atherosclerosis by altering the balance of effector and regulatory T cells.

METHODS AND RESULTS

To explore the effect of PIO on early and advanced atherosclerosis, apolipoprotein E deficient (ApoE-/-) mice were fed western diet and received PIO (20 mg/kg/day) by gastric gavage at 6 or 14 weeks of age, respectively for 8 weeks. Data showed PIO markedly inhibited early fatty streak formation. Further, although the advanced fibrofatty plaque sizes were not significantly reduced, the numbers of smooth muscle cells within lesions were increased and higher collagen concentrations were produced. In general, macrophage expression in lesions was decreased. Additionally, the expression of Foxp3(+) cells was increased in lesions and spleens in mice at all PIO treatment stages, whereas the CD4(+)IFN-γ(+)/CD4(+)IL-4(+) cell ratios were reduced.

CONCLUSION

PIO inhibited early atherosclerotic lesion formation and increased the stability of advanced atherosclerotic plaques in ApoE-/- mice, which was associated with altering the balance of effector and regulatory T cells.