Dietary exposure to organochlorine pesticide residues of the Hong Kong adult population from a total diet study

Dietary exposure of the Hong Kong adult population to organochlorine pesticide (OCP) residues was estimated using a total diet study (TDS) approach. OCPs listed under the Stockholm Convention as persistent organic pollutants (POPs) including, aldrin, dieldrin, chlordane, chlordecone, dichlorodiphenyltricholroethane (DDT), endosulfan, endrin, heptachlor, hexachlorobenzene (HCB), α-hexachlorocyclohexanes (HCH), β-HCH, lindane, mirex, pentachlorobenzene and toxaphene, were studied. Out of 600 composite samples, 55% contained one or more OCP residues at detectable levels. The most commonly detected OCP was DDT (32% of all composite samples), followed by HCB (30%) and endosulfan (22%). The lower- and upper-bound mean exposure estimates of OCP residues ranged from 0% to 0.5% and were 0.1-8.4% of their respective health-based guidance values (HBGVs). The lower- and upper-bound 95th percentile exposure estimates ranged from 0% to 1.2% and were 0.1-13.6% of their respective HBGVs. This indicated that dietary exposures to the OCP residues analysed would be unlikely to pose unacceptable health risks to Hong Kong adults.

Folic acid inhibits tau phosphorylation through regulation of PP2A methylation in SH-SY5Y cells

OBJECTIVES

Neurofibrillary tangles (NFTs), which are composed of intracellular filamentous aggregates of hyperphosphorylated tau protein, are one of the pathological hallmarks of Alzheimer's disease (AD). Because tau phosphorylation is regulated by phosphatases, abnormal metabolism of protein phosphatase 2A (PP2A) has been proposed to be a contributing factor to the disease process.

RESULTS

To determine the function of folic acid on tau phosphorylation, an in vitro model of human neuroblastoma cells (SH-SY5Y) were exposed to folic acid (0-40 μmol/L) for 96 h, in the presence or absence of the phosphoesterase inhibitor okadaic acid (OA) (10 nmol/L) for 9 h. The data of western blot showed tau phosphorylation at the Ser396 site in OA-incubated SH-SY5Y cells was inhibited by folic acid in a concentration-dependent manner, with the folic acid concentration of 40 μmol/L providing maximal inhibition. Folic acid can downregulate tau protein phosphorylation by inhibiting the demethylation reactions of PP2A. High folic acid concentrations (20 and 40 μmol/L) increased SAM:SAH ratios and cell viability.

CONCLUSION

Therefore, we can speculate that folate deficiency may be a cause of PP2A deregulation, which can in turn lead to expression of the abnormal hyperphosphorylated form of tau.

Potent and selective small-molecule MCL-1 inhibitors demonstrate on-target cancer cell killing activity as single agents and in combination with ABT-263 (navitoclax)

The anti-apoptotic protein MCL-1 is a key regulator of cancer cell survival and a known resistance factor for small-molecule BCL-2 family inhibitors such as ABT-263 (navitoclax), making it an attractive therapeutic target. However, directly inhibiting this target requires the disruption of high-affinity protein-protein interactions, and therefore designing small molecules potent enough to inhibit MCL-1 in cells has proven extremely challenging. Here, we describe a series of indole-2-carboxylic acids, exemplified by the compound A-1210477, that bind to MCL-1 selectively and with sufficient affinity to disrupt MCL-1-BIM complexes in living cells. A-1210477 induces the hallmarks of intrinsic apoptosis and demonstrates single agent killing of multiple myeloma and non-small cell lung cancer cell lines demonstrated to be MCL-1 dependent by BH3 profiling or siRNA rescue experiments. As predicted, A-1210477 synergizes with the BCL-2/BCL-XL inhibitor navitoclax to kill a variety of cancer cell lines. This work represents the first description of small-molecule MCL-1 inhibitors with sufficient potency to induce clear on-target cellular activity. It also demonstrates the utility of these molecules as chemical tools for dissecting the basic biology of MCL-1 and the promise of small-molecule MCL-1 inhibitors as potential therapeutics for the treatment of cancer.

MicroRNA-219-5p functions as a tumor suppressor partially by targeting platelet-derived growth factor receptor alpha in colorectal cancer

Platelet-derived growth factor receptor (PDGFR) signaling pathway was involved in the progress of colorectal cancer (CRC). By using the bioinformatic system online, we found that PDGFRα is a potential target of miR-219-5p. However, the expression pattern and underlying mechanisms of miR-219-5p had not been elucidated in CRC. Herein, we first evaluated the expression of miR-219-5p in tumor tissues by real-time polymerase chain reaction. Next, we confirmed that PDGFRα is the target of miR-219-5p by using luciferase report. And then, we investigated the biological functions of miR-219-5p in vitro in cell proliferation and apoptosis as well as cell cycle by gain and loss of function strategies. Data shown that miR-219-5p is down-regulated in CRC tissues compared with the corresponding matched normal tissues. PDGFRα was a direct target of miR-219-5p. Overexpression of miR-219-5p could inhibit cell proliferation, promote cell apoptosis and induce cell cycle arrest at the G1 phase. Furthermore, miR-219-5p suppressed the activation of the phosphatidylinositol 3-kinase/Akt signaling pathway and downregulated G1 cell-cycle-related protein cyclin D1, cyclin-dependent kinase (CDK) 4, and CDK6. Taken together, our results demonstrate that miR-219-5p functions as a tumor suppressor partially by targeting PDGFRα in colorectal cancer.

Resting-state brain function in schizophrenia and psychotic bipolar probands and their first-degree relatives

BACKGROUND

Schizophrenia (SCZ) and psychotic bipolar disorder (PBD) share considerable overlap in clinical features, genetic risk factors and co-occurrence among relatives. The common and unique functional cerebral deficits in these disorders, and in unaffected relatives, remain to be identified.

METHOD

A total of 59 healthy controls, 37 SCZ and 57 PBD probands and their unaffected first-degree relatives (38 and 28, respectively) were studied using resting-state functional magnetic resonance imaging (rfMRI). Regional cerebral function was evaluated by measuring the amplitude of low-frequency fluctuations (ALFF). Areas with ALFF alterations were used as seeds in whole-brain functional connectivity analysis. We then tested whether abnormalities identified in probands were present in unaffected relatives.

RESULTS

SCZ and PBD probands both demonstrated regional hypoactivity in the orbital frontal cortex and cingulate gyrus, as well as abnormal connectivity within striatal-thalamo-cortical networks. SCZ probands showed greater and more widely distributed ALFF alterations including the thalamus and bilateral parahippocampal gyri. Increased parahippocampal ALFF was related to positive symptoms and cognitive deficit. PBD patients showed uniquely increased functional connectivity between the thalamus and bilateral insula. Only PBD relatives showed abnormal connectivity within striatal-thalamo-cortical networks seen in both proband groups.

CONCLUSIONS

The present findings reveal a common pattern of deficits in frontostriatal circuitry across SCZ and PBD, and unique regional and functional connectivity abnormalities that distinguish them. The abnormal network connectivity in PBD relatives that was present in both proband groups may reflect genetic susceptibility associated with risk for psychosis, but within-family associations of this measure were not high.

Characterisation of metals in the electronic waste of complex mixtures of end-of-life ICT products for development of cleaner recovery technology

Recycling of valuable metals from electronic waste, especially complex mixtures of end-of-life information and communication technology (ICT) products, is of great difficulty due to their complexity and heterogeneity. One of the important reasons is the lack of comprehensive characterisation on such materials, i.e. accurate compositions, physical/chemical properties. In the present research, we focus on developing methodologies for the characterisation of metals in an industrially processed ICT waste. The morphology, particle size distribution, compositional distribution, occurrence, liberation as well as the thermo-chemical properties of the ICT waste were investigated with various characterisation techniques, including X-ray Fluorescence Spectrometry (XRF), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) with energy dispersed spectroscopy (EDS). Due to the high heterogeneity of the material, special sample preparation procedures were introduced to minimise the discrepancies during compositional analyses. As a result, a clearer overview of the ICT waste has been reached. This research provides better understanding of the extractability of each metal and improves the awareness of potential obstacles for extraction. It will lead to smarter decisions during further development of a clean and effective recovery process.

17-AAG enhances the cytotoxicity of flavopiridol in mantle cell lymphoma via autophagy suppression

Flavopiridol, a cyclin-dependent kinase inhibitor (CDKI), shows promising anti-tumor activity in hematologic malignancies. However, Flavopiridol-induced protective autophagy may lead to drug resistance. Here we found that Hsp90 inhibitor 17-AAG can sensitize mantle cell lymphoma (MCL) cells to flavopiridol by suppressing flavopiridol-triggered protective autophagy. The suppressing effect of 17-AAG on autophgy was mediated by Beclin1 degradation and ERK inactivation. Furthermore, 17-AAG enhanced flavopiridol-induced apoptosis and growth suppression in MCL cells. Our study may provide some insights into CDKI -targeted chemotherapies.

Blockade of the T cell immunoglobulin and mucin domain protein 3 pathway exacerbates sepsis-induced immune deviation and immunosuppression

Sepsis is a life-threatening condition, but the pathophysiological basis and biomarkers for the monitoring of sepsis and as targets for therapy remain to be determined. We have shown previously that T cell immunoglobulin and mucin domain protein 3 (Tim-3), a negative immune regulator, is involved in the physiopathology of sepsis, but the underlying mechanisms remain unclear. In the present study, we showed that Tim-3 signalling modulated the response patterns of both macrophages and T helper cells in sepsis. Blockade of the Tim-3 pathway exacerbated sepsis-induced proinflammatory macrophage responses and lymphocyte apoptosis during the early phase of sepsis, and enhanced the shift to anti-inflammatory responses for both macrophages and T helper cells during the late phase of sepsis. Tim-3 signalling was found to regulate CD80 and CD86 expression on macrophages both in vivo and in vitro. Co-culture of T cells with Tim-3 knock-down macrophages led to a biased T helper type 2 (Th2) response, partially explaining how Tim-3 signalling shapes inflammation patterns in vivo. Further studies on this pathway might shed new light on the pathogenesis of sepsis and suggest new approaches for intervention.

Chemical compositions and antiproliferation activities of the chloroform fraction from Pyropolyporus fomentarius in K562 cells

Pyropolyporus fomentarius, a fungus of the polyporaceae family, has been used in the treatment of various diseases, such as gastroenteric disorder, hepatocirrhosis, oral ulcer, inflammation, and several cancers. This study was conducted to investigate the compositions and cell growth inhibition effects of P. fomentarius chloroform (CHCl3) fraction and to clarify the possible mechanisms. Gas chromatography–mass spectrometry analysis was performed to investigate the composition of the P. fomentarius CHCl3 fraction. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Cell membrane damage was evaluated with a scanning electron microscope and flow cytometry following propidium iodide and bis-(1,3-dibarbituric acid)-trimethine oxanol staining. Apoptosis was analyzed using annexin V-PE/7-amino-actinomycin D (7-AAD) staining. Generation of intracellular calcium ion (Ca2+), reactive oxygen species (ROS), and changes of mitochondrial membrane potential (Δ ψm) were detected by flow cytometry using fluo 3-acetoxymethyl ester, 2′,7′-dichlorofluorescin-diacetate, and rhodamine 123. Our obtained data indicate that P. fomentarius CHCl3 fraction could inhibit proliferation of K562 cells depending on both the dosage and the incubation time, cause cell membrane damage, influence intracellular [Ca2+]i variation, promote the yield of ROS, decrease the level of Δψm, and initiate the apoptotic response in K562 cells.

Combination of high-intensity focused ultrasound irradiation and hydroxyapatite nanoparticle injection to injure normal goat liver tissue in vivo without costal bone incision

The aims of this study were to evaluate the in vivo safety of intravenous nano-hydroxyapatite (nano-HA), to explore how nano-HA might influence the effects of high-intensity focused ultrasound (HIFU) on normal liver tissue, and to investigate whether intravenous nano-HA could enhance HIFU for hepatocellular carcinoma ablation in a goat model. The present study, for the first time, indicated that the delivery of abundant nano-HA into the body over short periods of time could be assembled by the hepatic reticuloendothelial system, subsequently leading to a rapid rise of ultrasound-induced overheating, and ultimately resulting in enlargement of the coagulation necrotic area for ablated hepatocellular carcinoma in goats both in vivo and ex vivo. On the other hand, therapeutic doses of nano-HA were much lower than the lethal dose, and consequently presented transient and mild abnormalities of hepatic enzymes and renal function during the first 24 h after nano-HA injection. These results suggested that the combined application of nano-HA and HIFU is potentially a more effective alternative option compared to surgery for hepatocellular carcinoma local ablation in a safe and feasible manner.

Safety and efficacy of the modified peroral endoscopic myotomy with shorter myotomy for achalasia patients: a prospective study

Peroral endoscopic myotomy (POEM) has been developed as a minimally invasive endoscopic treatment for achalasia for years. However, the optimal length of submucosal tunnel and myotomy of muscle bundles during procedure of POEM has not yet been determined, so we aim to assess safety and efficacy of modified POEM with shorter myotomy of muscle bundles in achalasia patients. Consecutive achalasia patients had been performed modified POEM with shorter myotomy, and assessed by symptoms, high-resolution manometry, and barium swallow examinations before and 3 months after POEM for safety and efficacy evaluation. Modified POEM with shorter submucosal tunnel (mean length 6.8 cm) and endoscopic myotomy of muscle bundles (total mean length 5.4 cm) were completed in 46 consecutive achalasia patients. During the 3-month follow up in all cases, significant improvement of symptoms (a significant drop in the Eckardt score 8.4 ± 3.2 vs. 2.7 ± 1.9; P < 0.001), decreased lower esophageal sphincter pressure (39.4 ± 10.1 vs. 24.4 ± 9.1 mmHg; P < 0.001) and integrated relaxation pressure (38.6 ± 10.4 vs. 25.7 ± 9.6 mmHg; P < 0.01), and a drop in height of esophagus barium-contrast column (5.4 ± 3.1 vs. 2.6 ± 1.8 cm; P < 0.001) were observed. The frequencies of adverse events were lower in those under endotracheal anesthesia and CO2 insufflations compared with intravenous anesthesia and air insufflations. Only three patients were found to have gastroesophageal reflux disease on follow up. Modified POEM with shorter myotomy under endotracheal anesthesia and CO2 insufflations shows its good safety and excellent short-term efficacy in the treatment of achalasia. But further studies are warranted to assess the long-term efficacy.