EUK-134, a synthetic superoxide dismutase and catalase mimetic, prevents oxidative stress and attenuates kainate-induced neuropathology

The present study tested the effects of EUK-134, a synthetic superoxide dismutase/catalase mimetic, on several indices of oxidative stress and neuropathology produced in the rat limbic system as a result of seizure activity elicited by systemic kainic acid (KA) administration. Pretreatment of rats with EUK-134 did not modify the latency for or duration of KA-induced seizure activity. It did produce a highly significant reduction in increased protein nitration, activator protein-1- and NF-kappaB-binding activity, and spectrin proteolysis as well as in neuronal damage resulting from seizure activity in limbic structures. These results support the hypothesis that kainate-induced excitotoxicity is caused, at least in part, by the action of reactive oxygen species. Furthermore, they suggest that synthetic superoxide dismutase/catalase mimetics such as EUK-134 might be used to prevent excitotoxic neuronal injury.

Synthetic superoxide dismutase/catalase mimetics reduce oxidative stress and prolong survival in a mouse amyotrophic lateral sclerosis model

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that causes motoneuron degeneration, paralysis and death. Mutations in Cu, Zn superoxide dismutase (SOD1) are one cause of this disease. It is widely suspected that increased reactive oxidative species (ROS) is involved in motoneuron degeneration but whether such an involvement plays a role in ALS progression in vivo is uncertain. We treated mice expressing human mutant SOD1 G93A with EUK-8 and EUK-134, two synthetic SOD/catalase mimetics that have shown efficacy in several animal models of human diseases. These treatments reduced levels of oxidative stress and prolonged survival. The results suggest that oxidative stress plays an active role in ALS and illustrate the potential for treatment strategies aimed specifically against ROS.

Seizure activity results in a rapid induction of nuclear factor-kappa B in adult but not juvenile rat limbic structures

Previous studies have indicated that increased formation of oxygen free radicals is likely to participate in the cascade of events leading to neuronal damage following kainic acid (KA)-induced seizure activity. As reactive oxygen species are involved in signal transduction pathways leading to nuclear factor-kappaB (NF-kappaB) activation, we examined the effects of KA treatment on the activation of NF-kappaB in adult and juvenile rat brain. For comparison, changes in two other transcription factors, activator protein-1 (AP-1) and Sp1, were also determined. In adult rat piriform cortex and hippocampus, significant induction of NF-kappaB was observed at 4 h after KA injection, and the maximal increase was reached at 8-16 h posttreatment. NF-kappaB binding activities returned to control levels by 5 days after injection. NF-kappaB binding activities were slightly decreased in adult rat cerebellum at 8 and 16 h after KA treatment. In the juvenile rat, no significant changes in NF-kappaB binding activity were observed in piriform cortex, hippocampus, and cerebellum after KA injection. Changes in AP-1 binding activity were qualitatively similar to those observed with NF-kappaB in adult but not juvenile rat brain, as AP-1 was significantly induced in juvenile piriform cortex and hippocampus following KA injection. On the other hand, little or no changes in Sp1 activity were detected in adult and juvenile rat brain. Our results provide further evidence that oxidative stress participates in neuronal damage resulting from KA-induced seizure activity.

Changes in gut microbial populations, intestinal morphology, expression of tight junction proteins, and cytokine production between two pig breeds after challenge with Escherichia coli K88: a comparative study

This study hypothesized that the gut microbial populations, intestinal morphology, and cytokine production are differentially altered in 2 different pig breeds, namely, Chinese native Jinhua pigs and European Landrace pigs, after orally challenge with enterotoxigenic Escherichia coli (ETEC) K88. A total of 12 Jinhua pigs and 12 Landrace pigs were allocated to either the nonchallenged or the challenged groups (6 pigs per group). The challenged pigs were orally administered ETEC K88, and their nonchallenged counterparts were given sterile Luria-Bertani broth. Selected gut microbial populations, intestinal morphology, mRNA expression of tight junction proteins, and the levels of ileal cytokines and secretory immunoglobulin A (sIgA) production were measured in Jinhua and Landrace pigs. The results showed that the challenged Jinhua pigs exhibited a significantly (P < 0.05) lower incidence of diarrhea compared with their Landrace counterparts. The Escherichia coli (E.coli) population and the percentage of E. coli in the total bacteria population were increased in response to ETEC K88 challenge in both Jinhua and Landrace pigs. The challenged Landrace pigs shed more E. coli (P < 0.05) and had higher percentage of E. coli in the total bacteria population in the colon (P < 0.05) compared with their Jinhua counterparts. Both pig breeds tended to exhibit greater villous atrophy and crypt depth reduction in all of the intestinal segments with challenge. The expression of tight junction proteins decreased in response to ETEC K88 challenge in both pig breeds. The levels of the proinflammatory cytokines interferon (IFN)-γ, tumor necrosis factor-α, and IL-6 and the secretion of sIgA were positively altered whereas the levels of the anti-inflammatory cytokine IL-4 and transforming growth factor (TGF)-β were negatively altered by ETEC K88 challenge in both breeds. Jinhua pigs exhibited significantly higher levels of IFN-γ and TGF-β (P < 0.05) in the challenged group. Our findings provide valuable evidence to explain the differences in the intestinal physiology between Jinhua and Landrace pigs; that is, Jinhua pigs appeared to show better growth performance, a lower incidence of diarrhea, and a lower extent of immune activation in response to ETEC K88 challenge and a higher Lactobacillus population, a higher percentage of Lactobacillus in the total bacteria population, a higher ratio of Lactobacillus to E. coli, and higher levels of tight junction proteins with and without challenge.

S-allyl cysteine inhibits activation of nuclear factor kappa B in human T cells

Reactive oxygen species are involved in signal transduction pathways leading to nuclear factor kappa B (NF-kappa B) activation which has been implicated in the regulation of gene transcription. We recently reported that a garlic compound, S-allyl cysteine (SAC), protects bovine pulmonary artery endothelial cells from oxidant injury induced by hydrogen peroxide (H2O2). In this study we determined the effects of SAC on NF-kappa B activation in human T lymphocytes (Jurkat cells) induced by tumor necrosis factor alpha (TNF- alpha) and H2O2. Activated NF-kappa B in nuclear extracts was measured by an electrophoretic mobility shift assay using 32P-labeled probe. SAC consistently exhibited a dose-dependent inhibition of NF-kappa B activation induced by both TNF-alpha and H2O2. Supershift with specific antibodies to NF-kappa B subunits confirmed that the inducible retarded bands observed in the EMSA and p65-p50 heterodimer of the NF-kappa B/Rel protein. Our data suggest that SAC may act via antioxidant mechanisms to block NF-kappa B activation in Jurkat cells.

Tyrosine phosphorylation of ionotropic glutamate receptors by Fyn or Src differentially modulates their susceptibility to calpain and enhances their binding to spectrin and PSD-95

Both tyrosine phosphorylation and calpain-mediated truncation of ionotropic glutamate receptors are important mechanisms for synaptic plasticity. Previous work from our laboratory has shown that calpain activation results in truncation of the C-terminal domains of several glutamate receptor subunits. To test whether and how tyrosine phosphorylation of glutamate ionotropic receptor subunits modulates calpain susceptibility, synaptic membranes were phosphorylated by Fyn or Src, two members of the Src family tyrosine kinases. Tyrosine phosphorylation of synaptic membranes by Src significantly reduced calpain-mediated truncation of both NR2A and NR2B subunits of NMDA receptors, but not of GluR1 subunits of AMPA receptors. In contrast, phosphorylation with Fyn significantly protected calpain-mediated truncation of GluR1 subunits of AMPA receptors, but enhanced calpain-mediated truncation of NR2A subunits of NMDA receptors. Similar results were observed with NR2A and NR2B C-terminal domain fusion proteins phosphorylated by Fyn or Src before incubation with calpain and calcium. In addition, phosphorylation of NR2A and NR2B C-terminal fusion proteins by Fyn or Src enhanced their binding to spectrin and PSD-95. Thus, tyrosine phosphorylation impairs or facilitates calpain-mediated truncation of glutamate receptor subunits, depending on which tyrosine kinase is activated. Such mechanisms could serve to regulate receptor integrity and location, in addition to modulating channel properties.

Calpain-mediated regulation of NMDA receptor structure and function

Calpains have been previously shown to regulate AMPA receptor properties by producing partial truncation of the C-terminal domains of several receptor subunits. We now report that NMDA receptor subunits, in particular NR2 subunits, are also subjected to calpain-mediated truncation. Treatment of synaptic membranes with calpain I resulted in truncation of both NR1 and NR2 subunits, with the appearance of NR2 species with lower mol.wt. than native subunits, but still recognized by antibodies directed at the C-terminal domain. This treatment did not modify the binding of several ligands of the NMDA receptors, such as glutamate, glycine or TCP. Incubation of thin frozen-thawed brain sections with calcium resulted in calpain-mediated selective degradation of NR2 subunits, as truncation into smaller fragments was totally blocked by calpain inhibitors. Under the same conditions, TCP binding to sections was decreased by about 50%, an effect also blocked by calpain inhibitors. Treatment of hippocampal slices in culture with the excitotoxin, kainic acid, also produced calpain-mediated truncation of the C-terminal domain of NR2 but not NR1 subunits of the NMDA receptors. The results indicate that calpain activation produces several modifications of NMDA receptors, including the truncation of the C-terminal domain of NR2 subunits, and changes in channel binding properties. They suggest that calpain-mediated regulation of NMDA receptors might represent a feed-back regulation of the receptors which could be used to limit receptor activation.

Ginkgo biloba attenuates oxidative stress in macrophages and endothelial cells

The action of Ginkgo biloba extract (GBE) as an antioxidant was studied using various models of oxidative stress in macrophages and vascular endothelial cells. GBE was incubated with murine macrophages (J774) at 37 degrees C and 5% CO2 for 1 h; oxidative burst was triggered by zymosan. The intensity of fluorescence was measured directly in 96-well plates using a computerized microplate fluorometer at 485 nm excitation and 530 nm emission. GBE exhibited both time- and concentration-dependent suppression of oxidative burst. Confluent monolayers of bovine pulmonary artery endothelial cells (PAEC) were preincubated with different concentrations of GBE for 16 h, washed, and then exposed to an organic oxidant tert-butyl hydroperoxide (tBHP) for 2 h. Lipid peroxidation products of PAEC were determined by measuring thiobarbituric acid-reactive substances (TBARS). Cell injury was assessed by measuring the release of intracellular lactate dehydrogenase (LDH), and cell viability was determined by the methylthiazol tetrazolium (MTT) assay. tBHP increased production of TBARS in PAEC. Preincubation with GBE inhibited the increase of TBARS induced by tBHP. GBE protected biomembranes from oxidative injury by decreasing intracellular LDH leakage from PAEC. MTT assay showed that GBE minimized loss of cell viability induced by oxidative injury. The extensive antioxidant effect of GBE may be valuable to the prevention and treatment of various disorders related to free radical-induced pathology.

Calpain-mediated degradation of PSD-95 in developing and adult rat brain

PSD-95 is a major postsynaptic density protein that is degraded as a result of synaptic activity. We used four different methods to test the hypothesis that calpain is involved in PSD-95 turnover. Treatment of synaptic membranes with purified calpain resulted in a decrease in immunoreactivity of the native 95 kDa protein and the appearance of two smaller molecular weight species, migrating at 50 and 36 kDa, respectively. Calcium treatment of frozen-thawed brain sections produced an identical digestion pattern, an effect blocked by calpain inhibitors. N-methyl-D-aspartate treatment of organotypic hippocampal cultures produced truncation of PSD-95 and accumulation of the 36 kDa species. Finally, calpain-generated degradation products of PSD95 were prominent in neonatal hippocampus, and disappeared with postnatal development. Our data suggest that PSD-95 is a substrate for calpain, and that calpain-mediated truncation contributes to PSD-95 turnover.

Cocaine blocks HERG, but not KvLQT1+minK, potassium channels

Cocaine causes cardiac arrhythmias, sudden death, and occasionally long QT syndrome in humans. We investigated the effect of cocaine on the human K(+) channels HERG and KvLQT1+minK that encode native rapidly (I(Kr)) and slowly (I(Ks)) activating delayed rectifier K(+) channels in the heart. HERG and KvLQT1+minK channels were heterologously expressed in human embryonic kidney 293 cells, and whole-cell currents were recorded. Cocaine had no effect on KvLQT1+minK current in concentrations up to 200 microM. In contrast, cocaine reversibly blocked HERG current with half-maximal block of peak tail current of 7.2 microM. By using a protocol to quickly activate HERG channels, we found that cocaine block developed rapidly after channel activation. At 0 mV, the time constants for the development of block were 38.2 +/- 2.1, 15.2 +/- 0.8, and 6.9 +/- 1.1 ms in 10, 50 and 200 microM cocaine, respectively. Cocaine-blocked channels also recovered rapidly from block after repolarization. At -100 mV, recovery from block followed a biphasic time course with fast and slow time constants of 3.5 +/- 0.7 and 100.3 +/- 15.4 ms, respectively. Using N-methyl-cocaine, a permanently charged, membrane-impermeable cocaine analog, block of HERG channels rapidly developed when the drug was applied intracellularly through the patch pipette, suggesting that the cocaine binding site on the HERG protein is located on a cytoplasmic accessible domain. These results indicate that cocaine suppresses HERG, but not KvLQT1+minK, channels by preferentially blocking activated channels, that it unblocks upon repolarization, and does so with unique ultrarapid kinetics. Because the cocaine concentration range we studied is achieved in humans, HERG block may provide an additional mechanism for cocaine-induced arrhythmias and sudden death.

Src-mediated tyrosine phosphorylation of NR2 subunits of N-methyl-D-aspartate receptors protects from calpain-mediated truncation of their C-terminal domains

Src-mediated tyrosine phosphorylation of N-methyl-d-aspartate receptor subunits has been shown to modify the functional properties of N-methyl-d-aspartate receptors. Moreover, calpain-mediated truncation of N-methyl-d-aspartate receptor subunits has been found to alter the structure of the receptors. In the present study, we first used immunoprecipitation with a variety of antibodies against N-methyl-d-aspartate receptor subunits and anti-phosphotyrosine antibodies to show that tyrosine-phosphorylated subunits of N-methyl-d-aspartate receptor are protected against calpain-mediated truncation of their C-terminal domains. A GST fusion protein containing the C-terminal domain of NR2A was used to identify the calpain cutting sites in the C-terminal domain. One site was identified at residues 1278-1279, corresponding to one of the preferred calpain truncation sites. This site is adjacent to a consensus sequence for Src-mediated tyrosine phosphorylation, and Src-mediated tyrosine phosphorylation of the GST-NR2A C-terminal fusion protein also inhibited calpain-mediated truncation of the fusion protein. We propose that phosphorylation of NR2 subunits and the resulting inhibition of calpain-mediated truncation of their C-terminal domains provide for the stabilization of the N-methyl-d-aspartate receptors in postsynaptic structures.

Pycnogenol inhibits macrophage oxidative burst, lipoprotein oxidation, and hydroxyl radical-induced DNA damage

Pycnogenol (procyanidins extracted from Pinus maritima) has been reputed as a potent free-radical scavenger and an antioxidant phytochemical. We previously reported that pycnogenol prevents vascular endothelial cells from injury induced by an organic oxidant t-butyl hydroperoxide. In this study, we determined the effects of pycnogenol on (a) oxidative burst of macrophages, (b) oxidation of plasma low density lipoprotein (LDL), and (c) hydroxyl radical-induced breakage of plasmid DNA. Pycnogenol was incubated with J774 murine macrophages at 37 degrees C and 5% CO2 and oxidative burst was triggered by zymosan. The intensity of fluorescence was measured. Pycnogenol exhibited a concentration-dependent inhibition of oxidative burst. CuSO4 was used to oxidize human plasma LDL and the formation of thiobarbituric acid reactive substances (TBARS) was determined. Co-incubation with pycnogenol resulted in a concentration-dependent inhibition of LDL oxidation. Exposure of pBR322 plasmid DNA to iron/ascorbic acid system resulted in cleavage/damage of DNA by hydroxyl radical, measured by agarose gel electrophoresis. Pycnogenol significantly minimized this cleavage. The results indicate that pycnogenol exhibits an extensive antioxidant effect in all three in vitro systems.

Effect of homocysteine interventions on the risk of cardiocerebrovascular events: a meta-analysis of randomised controlled trials

AIMS

To evaluate the effects of homocysteine lowering intervention on the risk of cardiocerebrovascular events and all-cause mortality in randomised controlled trials among people with preexisting cardiocerebrovascular or renal disease.

METHODS

Studies were retrieved by searching MEDLINE and OVID (from January 1966 to December 2008) using the following keywords: homocysteine, hyperhomocysteinaemia, cardiovascular disease, coronary disease, cerebrovascular disease, B vitamins, folic acid, randomised controlled trial. References of all retrieved articles were also searched. Randomised controlled trials which compared folic acid or plus B vitamins supplementation with either placebo or usual care were evaluated with cardiocerebrovascular disease events or all-cause mortality reported as an end-point. Data on study design, characteristics of participants, changes in homocysteine levels, and cardiocerebrovascular events and all-cause mortality were independently abstracted by two investigators using a standardised protocol.

RESULTS

Seventeen trials involving 39,107 patients with preexisting cardiocerebrovascular or renal disease were included. Results of meta-analyses showed that no significant differences were identified between the intervention group and the control group. The overall relative risks (95% confidence intervals) of outcomes for patients treated with folic acid or plus B vitamins supplementation compared with controls were 1.01 (0.97-1.05) for cardiovascular events, 1.01 (0.94-1.07) for coronary heart disease, 0.94 (0.85-1.04) for stroke and 1.00 (0.95-1.05) for all-cause mortality. In the exclusion of low-quality trials and seven trials in grain fortification countries respectively, sensitivity analyses did not change the overall results.

CONCLUSION

There is no sufficient evidence to show that homocysteine lowering intervention can reduce the risk of cardiocerebrovascular diseases or all-cause mortality among people with preexisting vascular disease. Folic acid supplementation should not be recommended for the secondary prevention of cardiocerebrovascular diseases. More evidence from large-scale randomised controlled trials is needed to confirm this.

Highly photostable wide-dynamic-range pH sensitive semiconducting polymer dots enabled by dendronizing the near-IR emitters

One constraint of semiconducting polymer dots (Pdots), especially those with near-IR emission, is their low effective emitter ratio (∼1.5 mole percent), which limits their pH sensing performance. The other critical issue of existing Pdot-based pH sensors is their poor photostability. To address these issues, we developed a series of Pdots by dendronizing the squaraine-based pH responsive near-IR emitter, which is covalently incorporated into the polyfluorene (PFO) backbone. The fluorescence self-quenching of the NIR squaraine emitter was effectively suppressed at a high emitter concentration of 5 mole percent. Through controlling the individually incomplete energy transfer from the amorphous PFO donor to the blue β-phase PFO and NIR squaraine emitter, we obtained a ratiometric pH sensor with simultaneously improved pH sensitivity, brightness, and photostability. The Pdots showed a fast and reversible pH response over the whole biological pH range of 4.7 to 8.5. Intracellular pH mapping was successfully demonstrated using this ultra-bright and photostable Pdot-based pH indicator.

Status epilepticus induces p53 sequence-specific DNA binding in mature rat brain

Previous studies have implicated the tumor suppressor gene, p53, in neuronal apoptosis due to excitotoxin treatment. To test whether p53 protein functions as a transcription factor during excitotoxic cell death, we used electrophoretic mobility shift assays to measure p53 sequence-specific DNA-binding activity following kainic acid (KA)-induced seizures. A rapid and significant increase in p53 DNA-binding activity was observed in extracts from kainate-vulnerable brain regions at 2.5 h after seizure onset, an effect which lasted up to 16 h after seizure-onset. DNA binding activity returned to normal by 30 h after KA injection. Pre-treatment with the protein synthesis inhibitor cycloheximide, as well as pre-incubation with PAb421, a p53 monoclonal antibody, significantly attenuated p53 DNA-binding activity induced by KA treatment. These results indicate that p53 protein may function as a transcription factor, following KA treatment, to regulate the expression of p53-responsive genes involved in neuronal apoptosis.

Comparison of Mismatch Repair Status Between Primary and Matched Metastatic Sites in Patients With Colorectal Cancer

BACKGROUND

Differences between the features of primary cancer and matched metastatic cancer have recently drawn attention in research. This study investigated the concordance in microsatellite instability (MSI) and mismatch repair (MMR) status between primary and corresponding metastatic colorectal cancer (CRC).

METHODS

Consecutive patients with metastatic CRC who had both primary and metastatic tumors diagnosed at our institution in January 2008 through December 2016 were identified. Immunohistochemistry was used to test the MMR status of both primary and matched metastatic tumors, and PCR analysis was performed to test MSI in patients with deficient MMR (dMMR) status.

RESULTS

A total of 369 patients were included. Of the 46 patients with MSI-high primary tumors, 37 (80.4%) also had MSI-high metastatic tumors, whereas 9 (19.6%) had microsatellite stable (MSS) metastatic tumors. A high concordance was found in patients with liver, lung, or distant lymph node metastases. Interestingly, the discrepancy was more likely to be limited to peritoneal (5/20) or ovarian (4/4) metastasis (chi-square test, P<.001). These organ-specific features were also found in the pooled analysis. Along with the change of MSI-high in primary cancer to MSS in metastatic cancer, lymphocyte infiltration decreased significantly (P=.008). However, the change did not influence survival; the median overall survival of MSI-high and MSS metastatic tumors was 21.3 and 21.6 months, respectively (P=.774). The discrepancy rate was 1.6% for patients with proficient MMR primary tumors.

CONCLUSIONS

For patients with dMMR primary tumors, the concordance of MSI and MMR status in primary CRC and corresponding metastatic cancer is potentially organ-specific. High concordance is found in liver, lung, and distant lymph node metastases, whereas discrepancy is more likely to occur in peritoneal or ovarian metastasis. Rebiopsy to evaluate MSI-high/dMMR status might be needed during the course of anti-PD-1 therapy in cases of peritoneal or ovarian metastasis.

A comparative study of graphene-hydrogel hybrid bionanocomposites for biosensing

Hydrogels have become increasingly popular as immobilization materials for cells, enzymes and proteins for biosensing applications. Enzymatic biosensors that utilize hydrogel as an encapsulant have shown improvements over other immobilization techniques such as cross linking and covalent bonding. However, to date there are no studies which directly compare multiple hydrogel-graphene nanocomposites using the same enzyme and test conditions. This study compares the performance of four different hydrogels used as protein encapsulants in a mediator-free biosensor based on graphene-nanometal-enzyme composites. Alcohol oxidase (AOx) was encapsulated in chitosan poly-N-isopropylacrylamide (PNIPAAM), silk fibroin or cellulose nanocrystals (CNC) hydrogels, and then spin coated onto a nanoplatinum-graphene modified electrode. The transduction mechanism for the biosensor was based on AOx-catalyzed oxidation of methanol to produce hydrogen peroxide. To isolate the effect(s) of stimulus response on biosensor behavior, all experiments were conducted at 25 °C and pH 7.10. Electroactive surface area (ESA), electrochemical impedance spectroscopy (EIS), sensitivity to methanol, response time, limit of detection, and shelf life were measured for each bionanocomposite. Chitosan and PNIPAAM had the highest sensitivity (0.46 ± 0.2 and 0.3 ± 0.1 μA mM(-1), respectively) and electroactive surface area (0.2 ± 0.06 and 0.2 ± 0.02 cm(2), respectively), as well as the fastest response time (4.3 ± 0.8 and 4.8 ± 1.1 s, respectively). Silk and CNC demonstrated lower sensitivity (0.09 ± 0.02 and 0.15 ± 0.03 μA mM(-1), respectively), lower electroactive surface area (0.12 ± 0.02 and 0.09 ± 0.03 cm(2), respectively), and longer response time (8.9 ± 2.1 and 6.3 ± 0.8 s, respectively). The high porosity of chitosan, PNIPAAM, and silk gels led to excellent transport, which was significantly better than CNC bionanocomposites. Electrochemical performance of CNC bionanocomposites were relatively poor, which may be linked to poor gel stability. The differences between the Chitosan/PNIPAAM group and the Silk/CNC group were statistically significant (p < 0.05) based on ANOVA. Each of these composites was within the range of other published devices in the literature, while some attributes were significantly improved (namely response time and shelf life). The main advantages of these hydrogel composites over other devices is that only one enzyme is required, all materials are non-toxic, the sensor does not require mediators/cofactors, and the shelf life and response time are significantly improved over other devices.

A high LDL-C to HDL-C ratio predicts poor prognosis for initially metastatic colorectal cancer patients with elevations in LDL-C

Although lipid disequilibrium has been documented for several types of cancer including colorectal cancer (CRC), it remains unknown whether lipid parameters are associated with the outcome of metastatic CRC (mCRC) patients. Here, we retrospectively examined the lipid profiles of 453 mCRC patients and investigated whether any of the lipid parameters correlated with the outcome of mCRC patients. Pretreatment serum lipids, including triglyceride, cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), were collected in 453 initially mCRC patients. The LDL-C to HDL-C ratio (LHR) was calculated and divided into the first, second, and third tertiles. Univariate and multivariate analyses were performed to evaluate the impact of lipids on overall survival (OS) and progression-free survival (PFS). Nearly two-fifths of the patients (41.3%) exhibited elevations in LDL-C while most patients (88.3%) showed normal HDL-C levels. Decreased HDL-C (P=0.542) and increased LDL-C (P=0.023) were prognostic factors for poor OS, while triglyceride (P=0.542) and cholesterol (P=0.215) were not. Multivariate analysis revealed that LDL-C (P=0.031) was an independent prognostic factor. Triglyceride, cholesterol, HDL-C, and LDL-C did not correlate with PFS. Among patients with elevations in LDL-C levels, patients in the third tertile of the LHR had a markedly shorter median OS compared to those in the first or second tertile (P=0.012). Thus, increased LDL-C level is an independent prognostic factor for poor prognosis in mCRC patients, and a high LHR predicts poor prognosis for initially mCRC patients with elevations in LDL-C.

Post hoc support vector machine learning for impedimetric biosensors based on weak protein-ligand interactions

Impedimetric biosensors for measuring small molecules based on weak/transient interactions between bioreceptors and target analytes are a challenge for detection electronics, particularly in field studies or in the analysis of complex matrices. Protein-ligand binding sensors have enormous potential for biosensing, but achieving accuracy in complex solutions is a major challenge. There is a need for simple post hoc analytical tools that are not computationally expensive, yet provide near real time feedback on data derived from impedance spectra. Here, we show the use of a simple, open source support vector machine learning algorithm for analyzing impedimetric data in lieu of using equivalent circuit analysis. We demonstrate two different protein-based biosensors to show that the tool can be used for various applications. We conclude with a mobile phone-based demonstration focused on the measurement of acetone, an important biomarker related to the onset of diabetic ketoacidosis. In all conditions tested, the open source classifier was capable of performing as well as, or better, than the equivalent circuit analysis for characterizing weak/transient interactions between a model ligand (acetone) and a small chemosensory protein derived from the tsetse fly. In addition, the tool has a low computational requirement, facilitating use for mobile acquisition systems such as mobile phones. The protocol is deployed through Jupyter notebook (an open source computing environment available for mobile phone, tablet or computer use) and the code was written in Python. For each of the applications, we provide step-by-step instructions in English, Spanish, Mandarin and Portuguese to facilitate widespread use. All codes were based on scikit-learn, an open source software machine learning library in the Python language, and were processed in Jupyter notebook, an open-source web application for Python. The tool can easily be integrated with the mobile biosensor equipment for rapid detection, facilitating use by a broad range of impedimetric biosensor users. This post hoc analysis tool can serve as a launchpad for the convergence of nanobiosensors in planetary health monitoring applications based on mobile phone hardware.

Initial LDH level can predict the survival benefit from bevacizumab in the first-line setting in Chinese patients with metastatic colorectal cancer

Background

Markers to predict the efficacy of bevacizumab treatment have been not fully validated in most cancers, including metastatic colorectal cancer (mCRC). The aim of this study was to investigate the potential role of lactate dehydrogenase (LDH) in predicting the survival benefit from first-line bevacizumab treatment, in Chinese patients with mCRC.

Methods

All the patients were diagnosed with mCRC at the Sun Yat-sen University Cancer Center from 2003 to 2013. The study group and the control group were classified by receiving bevacizumab or not. The serum LDH value of all the patients had been detected before the first-line treatment. The primary end point was progression-free survival (PFS).

Results

The median PFS of the study and the control group (patients who received bevacizumab or not) was 11.3 and 9.1 months, respectively (P=0.004). In the control group, the median PFS of the high LDH level and the low LDH level groups was 6.9 and 10.2 months, respectively (P<0.001). However, in the study group, the corresponding median PFS was 9.9 and 11.9 months, respectively (P=0.145). In addition, for the low LDH level group, the median PFS was 11.9 and 10.2 months for patients who received bevacizumab or not, respectively (P=0.066); however, the median PFS of patients receiving bevacizumab or not was significantly different in the high LDH level group (9.9 and 6.9 months, respectively) (P=0.012).

Conclusion

The addition of bevacizumab in the first-line treatment setting could improve the PFS of mCRC patients notably. However, the benefit could only be potentially reflected on patients with high serum LDH level.

Apoptosis induced by hyperthermia in Dunn osteosarcoma cell line in vitro

The effect of hyperthermia at 43.5 degrees C for 1 h on Dunn osteosarcoma cells was studied. With sham-heated cells (37 degrees C, 1 h) as the control, the hyperthermia treated cells were divided into five groups. Time 0 group was the cells that were harvested immediately after heated at 43.5 degrees C for 1 h. Whereas time 3, 6, 12, and 24 h groups were the cells that were collected respectively after reincubation at 37 degrees C for the above different time periods. The appearance of hyperthermia-induced apoptosis of Dunn osteosarcoma cells was demonstrated to be time dependent. With the confocal microscopic study and TUNEL staining, the morphological characteristics of apoptosis, condensed nuclei and fragmented nuclei were obvious when reincubated at 37 degrees C for 6 h after hyperthermic treatment. This hyperthermia-induced apoptosis was further confirmed by flow cytometric analysis on DNA contents. The sub-G1 region that was proposed as a marker of apoptotic cells was most significantly elevated at 6 h after hyperthermic treatment and, thereafter, decreased to the levels of control values by 24 h, as the apoptotic cells underwent secondary necrosis and degraded to debris. The DNA strand breaks, considered as the key biochemical event of apoptosis, were detected by the TUNEL assay. This study indicated that hyperthermia (43.5 degrees C for 1 h) can induce apoptotic changes on osteosarcoma cells in vitro very rapidly (within 6 h after treatment), and its occurrence might not be detected if the samples are not taken at several early time points after hyperthermia.

Calpain-mediated truncation of rat brain AMPA receptors increases their Triton X-100 solubility

Previous studies have indicated that calpain activation results in the truncation of the C-terminal domains of AMPA and NMDA receptor subunits. The present study determined the distribution of the truncated species of the subunits between Triton-soluble and -insoluble fractions. Western blots were performed with various antibodies to quantify the amounts of the various species of GluR1, GluR2, GluR3 and NR2B subunits. The results indicate that calpain activation decreased the amount of all the intact subunits in Triton-insoluble fractions. Calpain-generated truncated forms of GluR1 and GluR2, but not NR2B, were absent in these fractions, and were recovered in Triton-soluble fractions. These findings suggest that calpain-mediated truncation of AMPA but not NMDA receptor C-terminal domains results in modifications of the interactions between the receptors and postsynaptic densities, and that this mechanism could be involved in activity-dependent changes in the subcellular distribution of AMPA receptors.

Association of body composition with survival and inflammatory responses in patients with non-metastatic nasopharyngeal cancer

OBJECTIVES

It is unknown whether or not the body composition is correlated with the prognosis and inflammatory response in patients with nasopharyngeal cancer (NPC).

MATERIALS AND METHODS

This cohort included 1767 patients with NPC. Visceral, subcutaneous and intra muscular adipose tissues (VAT, SAT and IMAT), and skeletal muscle index were quantified with computed tomography. We used the optimal stratification to select cut points for VAT, SAT and IMAT. We defined sarcopenia according to a widely used cut-point. The primary endpoint was overall survival (OS). The association between body composition and inflammatory response was also examined.

RESULTS

Low VAT, SAT, IMAT and sarcopenia were observed in 260 (14.7%), 451 (25.5%), 773 (43.7%) and 683 (38.7%) patients, respectively. Low VAT (P < 0.001, hazard ratio [HR], 1.884; 95% confidence interval [CI], 1.436-2.473,) and SAT (P = 0.022, HR, 1.334, 95%CI, 1.043-1.706) were both associated worse survival. IMAT and sarcopenia were not with prognostic value. In multivariate analysis, we found the prognostic value of the VAT (HR: 1.544, 95% CI: 1.128-2.114; P = 0.007) was independent of T stage, N stage, disease stage, lactic dehydrogenase, neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR), the systemic immune-inflammation index (SII), EBV-DNA and body mass index. We observed higher NLR (P = 0.028) and PLR (P < 0.001) in patients with low SAT. Both low VAT (P = 0.009) and SAT (P = 0.005) were associated with decreased stromal lymphocyte infiltrating intensity.

CONCLUSIONS

Among body composition parameters, VAT was an independent prognostic factor, especially in patients with locally advanced NPC.

Effects of PEMF on a murine osteosarcoma cell line: drug-resistant (P-glycoprotein-positive) and non-resistant cells

After pulsed exposure of Dunn osteosarcoma cells (nonresistant cells) to Adriamycin (ADR) at increasing concentrations and single-cell cloning of surviving cells, ADR-resistant cells were obtained. These resistant cells expressed P-glycoprotein and had resistance more than 10 times that of their nonresistant parent cells. Compared to the nonresistant cells not exposed to pulsing electromagnetic fields (PEMF) in ADR-free medium, their growth rates at ADR concentrations of 0.01 and 0.02 micrograms/ml, which were below IC50, were 83.0% and 61.8%, respectively. On the other hand, in the nonresistant cells exposed to PEMF (repetition frequency, 10 Hz; rise time, 25 microsec, peak magnetic field intensity, 0.4-0.8 mT), the growth rate was 111.9% in ADR-free medium, 95.5% at an ADR concentration of 0.01 micrograms/ml, and 92.2% at an ADR concentration of 0.02 micrograms/ml. This promotion of growth by PEMF is considered to be a result of mobilization of cells in the non-proliferative period of the cell cycle due to exposure to PEMF. However, at ADR concentrations above the IC50, the growth rate tended to decrease in the cells not exposed to PEMF. This may be caused by an increase in cells sensitive to ADR resulting from mobilization of cells in the non-proliferative period to the cell cycle. The growth rate in the resistant cells exposed to PEMF was significantly lower than that in the non-exposed resistant cells at all ADR concentrations, including ADR-free culture (P</=0.0114). Therefore, this study suggests that PEMF promotes the growth of undifferentiated cells but progressively suppresses the growth of more differentiated cells, i.e., PEMF controls cell growth depending on the degree of cell differentiation. This study also shows the potentiality of PEMF as an adjunctive treatment method for malignant tumors.

Probing the salmeterol binding site on the beta 2-adrenergic receptor using a novel photoaffinity ligand, [(125)I]iodoazidosalmeterol

Salmeterol is a long-acting beta2-adrenergic receptor (beta 2AR) agonist used clinically to treat asthma. In addition to binding at the active agonist site, it has been proposed that salmeterol also binds with very high affinity at a second site, termed the "exosite", and that this exosite contributes to the long duration of action of salmeterol. To determine the position of the phenyl ring of the aralkyloxyalkyl side chain of salmeterol in the beta 2AR binding site, we designed and synthesized the agonist photoaffinity label [(125)I]iodoazidosalmeterol ([125I]IAS). In direct adenylyl cyclase activation, in effects on adenylyl cyclase after pretreatment of intact cells, and in guinea pig tracheal relaxation assays, IAS and the parent drug salmeterol behave essentially the same. Significantly, the photoreactive azide of IAS is positioned on the phenyl ring at the end of the molecule which is thought to be involved in exosite binding. Carrier-free radioiodinated [125I]IAS was used to photolabel epitope-tagged human beta 2AR in membranes prepared from stably transfected HEK 293 cells. Labeling with [(125)I]IAS was blocked by 10 microM (-)-alprenolol and inhibited by addition of GTP gamma S, and [125I]IAS migrated at the same position on an SDS-PAGE gel as the beta 2AR labeled by the antagonist photoaffinity label [125I]iodoazidobenzylpindolol ([125I]IABP). The labeled receptor was purified on a nickel affinity column and cleaved with factor Xa protease at a specific sequence in the large loop between transmembrane segments 5 and 6, yielding two peptides. While the control antagonist photoaffinity label [125I]IABP labeled both the large N-terminal fragment [containing transmembranes (TMs) 1-5] and the smaller C-terminal fragment (containing TMs 6 and 7), essentially all of the [125I]IAS labeling was on the smaller C-terminal peptide containing TMs 6 and 7. This direct biochemical evidence demonstrates that when salmeterol binds to the receptor, its hydrophobic aryloxyalkyl tail is positioned near TM 6 and/or TM 7. A model of IAS binding to the beta 2AR is proposed.