Fullerol rescues the light-induced retinal damage by modulating Müller glia cell fate

Excessive light exposure can damage photoreceptors and lead to blindness. Oxidative stress serves a key role in photo-induced retinal damage. Free radical scavengers have been proven to protect against photo-damaged retinal degeneration. Fullerol, a potent antioxidant, has the potential to protect against ultraviolet-B (UVB)-induced cornea injury by activating the endogenous stem cells. However, its effects on cell fate determination of Müller glia (MG) between gliosis and de-differentiation remain unclear. Therefore, we established a MG lineage-tracing mouse model of light-induced retinal damage to examine the therapeutic effects of fullerol. Fullerol exhibited superior protection against light-induced retinal injury compared to glutathione (GSH) and reduced oxidative stress levels, inhibited gliosis by suppressing the TGF-β pathway, and enhanced the de-differentiation of MG cells. RNA sequencing revealed that transcription candidate pathways, including Nrf2 and Wnt10a pathways, were involved in fullerol-induced neuroprotection. Fullerol-mediated transcriptional changes were validated by qPCR, Western blotting, and immunostaining using mouse retinas and human-derived Müller cell lines MIO-M1 cells, confirming that fullerol possibly modulated the Nrf2, Wnt10a, and TGF-β pathways in MG, which suppressed gliosis and promoted the de-differentiation of MG in light-induced retinal degeneration, indicating its potential in treating retinal diseases.

A controllable perfusion microfluidic chip for facilitating the development of retinal ganglion cells in human retinal organoids

Retinal organoids (ROs) derived from human pluripotent stem cells (hPSCs) have become a promising model in vitro to recapitulate human retinal development, which can be further employed to explore the mechanisms of retinal diseases. However, the current culture systems for ROs lack physiologically relevant microenvironments, such as controllable mechano-physiological cues and dynamic feedback between cells and the extracellular matrix (ECM), which limits the accurate control of RO development. Therefore, we designed a controllable perfusion microfluidic chip (CPMC) with the advantages of precisely controlling fluidic shear stress (FSS) and oxygen concentration distribution in a human embryonic stem cell (hESC)-derived RO culture system. We found that ROs cultured under this system allow for expanding the retinal progenitor cell (RPC) pool, orchestrating the retinal ganglion cell (RGC) specification, and axon growth without disturbing the spatial and temporal patterning events at the early stage of RO development. Furthermore, RNA sequencing data revealed that the activation of voltage-gated ion channels and the increased expression of ECM components synergistically improve the growth of ROs and facilitate the differentiation of RGCs. This study elaborates on the advantages of the designed CPMC to promote RO growth and provide a controllable and reliable platform for the efficient maturity of RGCs in the ROs, promising applications in modeling RGC-related disorders, drug screening, and cell transplantation.

Fullerenol protects cornea from ultraviolet B exposure

The eyes are highly susceptible to the oxidative stress induced by ultraviolet B (UVB, wavelength between 280 ∼ 320 nm), which could cause severe damage to the cornea. Fullerenols are effective antioxidants to alleviate UVB-induced injury, while their application for the eyes is still rare. In present study, we investigated the protective performance and mechanism of fullerenols on cornea under UVB radiation in vivo and in vitro. The synthesized fullerenols exhibited broad-spectrum free radical scavenging properties (applicable to both reactive oxygen species (ROS) and reactive nitrogen species (RNS)) and photo-stability. When compared with another widely used antioxidant glutathione (GSH), the administration of fullerenols markedly decreased the injured area, corneal edema, cell death, and increased the cell proliferation in UVB-induced rat cornea. The effects of fullerenols were confirmed in UVB-exposed human corneal epithelial cells (hCECs), where elevated cell viability and proliferation, decreased oxidative free radical production, repaired mitochondrial dysfunction and DNA lesions were observed. RNA sequencing (RNA-Seq) analysis demonstrated that fullerenol alleviated UVB-induced corneal injury through down-regulation of oxidative stress-related genes and up-regulation of proliferation-associated genes. Our results demonstrate the suitability of fullerenols as a potential exogenous treatment in ameliorating UVB-induced cornea damage.

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Fullerenol produces significant precaution on UVB-induced corneal damage.

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Fullerenol exhibits broader spectrum free radical scavenging properties than GSH.

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Fullerenol mitigates the LSCs loss in the cornea caused by UVB.

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Fullerenol down-regulates oxidative stress genes and up-regulates proliferation-related genes.

0281 Sleep Deprivation Impairs Cooperative Behavior Selectively: Evidence from Prisoner’s and Chicken Dilemmas

Introduction

Cooperation, the cornerstone of human interaction, has attracted much attention since it was indispensable in the contemporary world. However, little research has been done on whether sleep deprivation altered human cooperative behavior. In the present work, we investigated cooperation and sleep deprivation directly, aiming to evaluate the influences of acute sleep deprivation on cooperation with two classical social dilemmas, the Prisoner’s dilemma (PD) and the chicken dilemma (CD).

Methods

All participants (N=24) were required to come for the experiments twice, one time for normal sleep condition, the other time for sleep deprivation condition, with a counter-balanced sequence. In the following afternoon, participants completed the psychomotor vigilance task (PVT) and two social dilemmas tasks, as well as the Karolinska Sleepiness Scale (KSS), the Risk Orientation Questionnaire (ROQ) and the Positive and Negative Affect Schedule (PANAS).

Results

Our results demonstrated that sleep deprivation significantly impaired cooperative behaviors in the CD but not in the PD. In addition, this detrimental effect was not related with the alteration in the risk-seeking, objective alertness, subjective sleepiness, and mood.

Conclusion

The current findings revealed that sleep deprivation impairs human cooperative behaviors selectively. However, the underlying mechanism remains to further explore with neuroimaging studies and focus on the mediating role of general trust and sensitivity of loss.

Support

This research was supported by the National Natural Science Foundation of China (31500906), Guangdong Natural Science Funding - General Program (2019A1515012182).

The global soil community and its influence on biogeochemistry

Soil organisms represent the most biologically diverse community on land and govern the turnover of the largest organic matter pool in the terrestrial biosphere. The highly complex nature of these communities at local scales has traditionally obscured efforts to identify unifying patterns in global soil biodiversity and biogeochemistry. As a result, environmental covariates have generally been used as a proxy to represent the variation in soil community activity in global biogeochemical models. Yet over the past decade, broad-scale studies have begun to see past this local heterogeneity to identify unifying patterns in the biomass, diversity, and composition of certain soil groups across the globe. These unifying patterns provide new insights into the fundamental distribution and dynamics of organic matter on land.

Association of PON1 gene polymorphisms with polycystic ovarian syndrome risk: a meta-analysis of case-control studies

PURPOSE

Evidences showed that paraoxonase 1 (PON1) gene polymorphism has an impact on women's susceptibility to polycystic ovarian syndrome (PCOS) by influencing the expression and activity of PON1. However, the effects of three PON1 polymorphisms (- 108 C>T, L55M and Q192R) on the incidence of PCOS have generated inconsistent results. Here, we conducted a meta-analysis to investigate the association between PON1 polymorphisms and PCOS risk.

METHODS

All eligible trials were identified via systematic searches of multiple literature databases. Outcome data were synthesized by using crude odds ratio with 95% confidence interval. Heterogeneity was assessed with the I² test. Publication bias and subgroup analyses were also performed.

RESULTS

A total of 2449 cases and 1977 controls from nine studies were selected for analysis. The pooled results showed a significant association between PCOS risk and PON1 - 108 C/T polymorphism in the following genetic models [allelic, 0.72 (0.56-0.92); homozygote, 0.51 (0.32-0.82); heterozygote, 0.44 (0.25-0.78); and dominant 0.47 (0.29-0.77)]. For the PON1 192 Q/R polymorphism, a significant relationship was found in the allelic model [0.62 (0.41-0.93)] and recessive model [0.61 (0.37-0.98)]. PCOS risk was also linked to PON1 L55M polymorphism in the heterozygote model [0.62 (0.39-0.98)] and dominant model [0.63 (0.41-0.96)].

CONCLUSIONS

Our study has shown that PON1 - 108 C/T polymorphism might be associated with increased risk of PCOS under the allelic, homozygote, heterozygote, and dominant models. Additionally, PON1 192 Q/R and L55M polymorphisms were significantly related only in the allelic and recessive model, and in the heterozygote and dominant model, respectively.

Berberine Ameliorates Periodontal Bone Loss by Regulating Gut Microbiota

Postmenopausal osteoporosis (PMO) is a risk factor for periodontitis, and current therapeutics against PMO prevent the aggravated alveolar bone loss of periodontitis in estrogen-deficient women. Gut microbiota is recognized as a promising therapeutic target for PMO. Berberine extracted from Chinese medicinal plants has shown its effectiveness in the treatment of metabolic diseases such as obesity and diabetes via regulating gut microbiota. Here, we hypothesize that berberine ameliorates periodontal bone loss by improving the intestinal barriers by regulating gut microbiota under an estrogen-deficient condition. Experimental periodontitis was established in ovariectomized (OVX) rats, and the OVX-periodontitis rats were treated with berberine for 7 wk before sacrifice for analyses. Micro–computed tomography and histologic analyses showed that berberine treatment significantly reduced alveolar bone loss and improved bone metabolism of OVX-periodontitis rats as compared with the vehicle-treated OVX-periodontitis rats. In parallel, berberine-treated OVX-periodontitis rats harbored a higher abundance of butyrate-producing gut microbiota with elevated butyrate generation, as demonstrated by 16S rRNA sequencing and high-performance liquid chromatography analysis. Berberine-treated OVX-periodontitis rats consistently showed improved intestinal barrier integrity and decreased intestinal paracellular permeability with a lower level of serum endotoxin. In parallel, IL-17A-related immune responses were attenuated in berberine-treated OVX-periodontitis rats with a lower serum level of proinflammatory cytokines and reduced IL-17A+ cells in alveolar bone as compared with vehicle-treated OVX-periodontitis rats. Our data indicate that gut microbiota is a potential target for the treatment of estrogen deficiency–aggravated periodontal bone loss, and berberine represents a promising adjuvant therapeutic by modulating gut microbiota.

[Value of base excess in predicting the prognosis of patients with paraquat poisoning]

Objective: To explore prognostic factors of acute paraquat poisoning (APP) , analyze the correlation between base excess (BE) and plasma concentration of paraquat (C-PQ) and discuss BE level in evalua-tion of prognosis of acute paraquat poisoning patients. Methods: We retrospectively selected 84 APP patients who admitted to Emergency Intensive Care Unit (EICU) of our hospital from 2009.9.1 to 2015.8.31.Clinical data from 84 APP patients were analyzed. BE、C-PQ、time of gastric lavagesince ingestion、time of hemoperfusion since ingestion、severity index of paraquat poisoning (SIPP) 、white blood cell (WBC) 、percentage of neutrophils (N%) 、hemoglobin (HB) 、creatinine (Cr) 、alanine aminotransferase (ALT) 、aspartate aminotransferase (AST) 、partial pressure of oxygen (PaO(2)) 、partial pressure of carbon dioxide (PaCO(2)) and other laboratory parameters were measured. A total of 41 patients in non-survivors died during the 30 days after admission and 43 patients in survivors survived during the 30 days. The factors of prognosis in paraquat poisoining and the role of BE in evalu-ating prognosis was analyzed, as well as the correlation between BE and C-PQ. Results: 1.Logistic regression analyses showed BE、C-PQ、ALT、AST、Cr was of prognostic significance[odds ratio (OR) of BE: 0.511, 95%CI 0.267, 0.978; C-PQ:-=0.999, 95%CI 0.999, 1.000; both P<0.05] ; 2.The area under the receiver operating characteristic curve (ROC curve) of BE、C-PQ and prognosis were 0.775、0.927 respectively, BE≤-1.7 mmol/L was the best cut-off value, the sensitivity、specificity for predicting were 82.9%、62.8%, the evaluation value was lower to C-PQ>3 273.935 ng/ml (AUC 0.927, 78.0%、95.3%) ; 3.BE negative correlated with C-PQ[-1.100 (-4.100, -0.200) , -5.900(-8.650, -2.500) , both P<0.05]. (r=-0.4, P<0.01). Conclusion: These results suggest that BE may be useful for the prediction of prognosis in PQ poisoning and BE negative correlated with C-PQ.

CO2reforming of methane over highly active La-promoted Ni supported on SBA-15 catalysts: mechanism and kinetic modelling

Various Ni catalysts were synthesized by combining a high surface area SBA-15 support, a novel preparation method using an oleic acid precursor to obtain highly dispersed and small Ni particles, and the basic property of La.

Bimetallic Ni–Cu alloy nanoparticles supported on silica for the water-gas shift reaction: activating surface hydroxyls via enhanced CO adsorption

Strong CO adsorption activates surface OH for enhanced WGS activity.

Dendritic cell CD83 homotypic interactions regulate inflammation and promote mucosal homeostasis

Dendritic cells (DCs) form an extensive network in the intestinal lamina propria, which orchestrates the mucosal immune response. Alterations in DC function can predispose to inflammatory bowel disease, although by unknown mechanisms. We show that CD83, a highly regulated DC cell surface protein, modulates the immune response to prevent colitis. Mice with a conditional knockout of CD83 in DCs develop exacerbated colitis following dextran sodium sulfate challenge, whereas mucosal overexpression of CD83 inhibits DC inflammatory response and protects against colitis. These CD83 perturbations can be modeled in vitro where we show that CD83 homotypic interaction occurs via cell-cell contact and inhibits pro-inflammatory responses. CD83 knockdown or cytoplasmic truncation abrogates the effects of homotypic binding. We demonstrate that CD83 homotypic interaction regulates DC activation via the mitogen-activated protein kinase pathway by inhibiting p38α phosphorylation. Our findings indicate that CD83 homotypic interactions regulate DC activation and promote mucosal homeostasis.

Increased dosage of cyclosporine induces myopathy with increased seru creatine kinase in an elderly patient on chronic statin therapy

WHAT IS KNOWN AND OBJECTIVE

The concomitant administration of atorvastatin and cyclosporine has been shown to increase the serum concentration of 3-hydroxy-3-methylglutaryl coenzyme A, which may be associated with the elevation of creatine kinase and an increased risk of myopathy. Our objective is to report on a case of statin-induced myopathy associated with concomitant use of cyclosporine and other contributing factors.

CASE SUMMARY

An 88-year-old Chinese male patient with comorbidities received polypharmacy treatment, including atorvastatin and cyclosporine. After the dosage of cyclosporine was increased to 300 mg every day for 8 months, the patient developed body pain and leg weakness, with a serum creatine kinase increase and evidence on magnetic resonance imaging of muscle oedema.

WHAT IS NEW AND CONCLUSION

Cyclosporine is a moderate inhibitor of the cytochrome P450 CYP3A4 isoenzyme, which is known to increase the serum level of atorvastatin. We hypothesized that the pharmacological and pharmacokinetic properties of atorvastatin-induced myopathy are the result of its interaction with high dosage of cyclosporine.

Relationship between diffusion-weighted imaging and Bcl-2 expression in rabbit models of hepatic VX2 tumors after radiotherapy

The paper aims to study diffusion-weighted imaging (DWI) and Bcl-2 gene expression in hepatic VX2 tumors after three-dimensional conformal radiotherapy (3D-CRT), we successfully developed 40 rabbit models with hepatic VX2 tumors. 3D-CRT was performed on 28 rabbit hepatic VX2 tumors, which were then randomly and evenly divided into four groups. The remaining 12 controls did not receive radiotherapy. Conventional and DWI was performed at 1, 5, 10, and 15 days following radiation therapy. We measured apparent diffusion coefficients (ADCs) in both a region of interest (ROI) of the VX2 tumor tissue and normal liver tissue and then calculated the ratio between them. RT-PCR was performed to detect the expression of the anti-apoptotic gene Bcl-2. On days 5 and 10, the ADC ratios of the radiotherapy groups were 1.322+-0.270 and 0.964+-0.341, respectively. On days 5, 10, and 15, Bcl-2 gene expression in the radiotherapy group was 0.563+-0.284, 0.421+-0.242, and 0.314+-0.152, respectively. For all three days, the gene expression values from the radiotherapy group were significantly lower than that in the control group (P less than 0.01). Statistical analysis revealed that ADC ratio and Bcl-2 gene expression were significantly negatively correlated (r=-0.493, P less than 0.01). Our results demonstrated that DWI sequence can reflect molecular changes at different time points for hepatic VX2 tumors following radiotherapy.

Formononetin-induced apoptosis of human prostate cancer cells through ERK1/2 mitogen-activated protein kinase inactivation

Formononetin is a main active component of red clover plants (Trifolium pratense L.), and is considered as a phytoestrogen. Our previous studies demonstrated that formononetin caused cell cycle arrest at the G0/G1 phase by inactivating insulin-like growth factor 1(IGF1)/IGF1R-phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in MCF-7 cells. In the present study, we investigated the molecular mechanisms involved in the effect of formononetin on prostate cancer cells. Our results suggested that higher concentrations of formononetin inhibited the proliferation of prostate cancer cells (LNCaP and PC-3), while the most striking effect was observed in LNCaP cells. We further found that formononetin inactivated extracellular signal-regulated kinase1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signaling pathway in a dose-dependent manner, which resulted in increased the expression levels of BCL2-associated X (Bax) mRNA and protein, and induced apoptosis in LNCaP cells. Thus, we concluded that the induced apoptosis effect of formononetin on human prostate cancer cells was related to ERK1/2 MAPK-Bax pathway. Considering that red clover plants were widely used clinically, our results provided the foundation for future development of different concentrations formononetin for treatment of prostate cancer.

Calibration of the Capintec CRC-712M dose calibrator for 18F

Primary standardisation was performed on a solution of (18)F using the 4pibeta-gamma coincidence counting efficiency-tracing extrapolation method with (60)Co used as a tracer nuclide. The result was used to calibrate the ANSTO secondary standard ionisation chamber which is used to disseminate Australian activity standards for gamma emitters. Using the secondary activity standard for (18)F, the Capintec CRC-712M dose calibrator at the Australian National Medical Cyclotron (NMC) Positron Emission Tomography (PET) Quality Control (QC) Section was calibrated. The dial setting number recommended by the manufacturer for the measurement of the activity of (18)F is 439. In this work, the dial setting numbers for the activity measurement of the solution of (18)F in Wheaton vials were experimentally determined to be 443+/-12, 446+/-12, 459+/-11, 473+/-15 for 0.1, 1, 4.5 and 9ml solution volumes, respectively. The uncertainties given above are expanded uncertainties (k=2) giving an estimated level of confidence of 95%. The activities determined using the manufacturer recommended setting number 439 are 0.8%, 1.4%, 4.0% and 6.5% higher than the standardised activities, respectively. It is recommended that a single dial setting number of 459 determined for 4.5ml is used for 0.1-9ml solution in Wheaton vials in order to simplify the operation procedure. With this setting the expended uncertainty (k=2) in the activity readout from the Capintec dose calibrator would be less than 6.2%.

Development of an Australian secondary standard for the reference air kerma rate measurement of125I seeds

Calibration of a High-Dose-Rate 1000 Plus ionisation chamber and associated electrometer for the determination of reference air kerma rate for 125I brachytherapy seeds has been developed. Traceability was established from ionisation chamber measurements of an Amersham model 6711 125I seed for which a primary standard measurement of reference air kerma rate has been made by the National Institute of Standards and Technology. The status of an Australian secondary standard is to be realised by establishing legal verifying authority from the National Measurement Institute. The calibrated chamber thus provides a measurement from which similar chambers in hospitals may be calibrated. For quality assurance this result was compared with the calibration certificate supplied by the Accredited Dosimetry Calibration Laboratory of the University of Wisconsin, USA.

Development of activity standard for 90Y microspheres

(90)Y microspheres are important therapeutic radiopharmaceuticals used in the treatment of liver cancer through a process known as selective internal radiation therapy. SIR-spheres is a radiopharmaceutical product that is comprised of (90)Y microspheres suspended in sterile, pyrogen-free water for injection into patients. It is necessary to establish for the SIR-spheres production the capability of accurately measuring the activity of this product to a traceable national measurement standard. An activity standard for SIR-spheres was developed from a standard for (90)Y solution, employing a highly quantifiable chemical digestion process. Calibration factors for the manufacturer's ionisation chambers were determined for 1 and 5 ml of the SIR-spheres product placed in Wheaton vials, for both 34% and 44% of (90)Y microsphere concentration.

ClC-5 chloride channel alters expression of the epithelial sodium channel (ENaC)

ClC-5 chloride channels and epithelial sodium channels (ENaC) are present in many cell types including airway and retinal epithelia. Since ENaC activity is known to be affected by chloride transport, we co-injected Xenopus oocytes with cRNAs encoding ENaC and ClC-5 to investigate whether channel currents are impacted by heterologous co-expression of these proteins. ClC-5 currents were not detectably affected by co-expression with ENaC, whereas amiloride-sensitive ENaC currents were significantly lower compared to control oocytes expressing ENaC alone. Co-expression of ENaC with cRNA sequences encoding non-conducting fragments of ClC-5 revealed that the amino acid sequence region between positions 347 and 647 was sufficient for inhibition of ENaC currents. Co-expression of ENaC and another transport protein, the sodium dicarboxylate co-transporter (NaDC-1), did not affect ENaC currents. To test whether the inhibitory effects of ClC-5 were specific for ENaC, ClC-5 was also co-expressed with CFTR. CFTR currents were also inhibited by co-expression with ClC-5, whereas ClC-5 currents were unaffected. Western blot analysis of biotinylated oocyte surface membranes revealed that the co-expression of ClC-5 with ENaC, CFTR, or NaDC-1 decreased the abundance of these proteins at the surface membrane. We conclude that overexpression of ClC-5, specifically amino acids 347-647, can alter the normal translation or trafficking of ENaC and other ion transport proteins by a mechanism that is independent of the chloride conductance of ClC-5.

Three-dimensional model and molecular mechanism of Mycobacterium tuberculosis catalase-peroxidase (KatG) and isoniazid-resistant KatG mutants

Mycobacterium tuberculosis KatG enzyme functions both as catalase for removing hydrogen peroxide (H(2)O(2)) and as peroxidase for oxidating isoniazid (INH) to active form of anti-tuberculosis drug. Although mutations in M. tuberculosis KatG confer INH resistance in tuberculous patients, structural bases for INH-resistant mutations in the KatG gene remains poorly understood. Here, three M. tuberculosis KatG mutants bearing Arg418--> Gln, Ser315 --> Thr, or Trp321 --> Gly replacement were assessed for changes in catalase-peroxidase activities and possible structure bases relevant to such changes. These three M. tuberculosis KatG mutants exhibited a marked impairment or loss of catalase-peroxidase activities. The possible structural bases for the mutant-induced loss of enzyme activities were then analyzed using a three-dimensional model of M. tuberculosis KatG protein constructed on the basis of the crystal structure of the catalase-peroxidase from Burkholderia pseudomallei. The model suggests that three M. tuberculosis KatG mutants bearing Arg418 --> Gln, Ser315 -->Thr, or Trp321--> Gly replacement affect enzyme activities by different mechanisms, although each of them impacts consequently on a heme-associated structure, the putative oxidative site. Moreover, in addition to the widely accepted substrate-binding site, M. tuberculosis KatG may bear another H(2)O(2) binding site. This H(2)O(2) binding site appears to interact with the catalytic site by a possible electron-transfer chain, a Met255-Tyr229-Trp107 triad conserved in many catalase-peroxidases. The Ser315 --> Thr mutant may have direct effect on the catalytic site by interfering with electron transfer in addition to the previously proposed mechanism of steric constraint.

Coexpression of complementary fragments of ClC-5 and restoration of chloride channel function in a Dent's disease mutation

The human hereditary disorder Dent's disease is linked to loss-of-function mutations of the chloride channel ClC-5. Many of these mutations involve insertion of premature stop codons, resulting in truncation of the protein. We determined whether the functional activity of ClC-5 could be restored by coexpression of the truncated protein (containing the NH2-terminal region) with its complementary “missing” COOH-terminal region. Split channel constructs for ClC-5, consisting of complementary N and C protein regions, were created at an arbitrary site in the COOH-terminal region (V655) and at four Dent's disease mutation sites (R347, Y617, R648, and R704). Coexpression of complementary fragments for the split channel at V655 produced currents with anion and pH sensitivity similar to those of wild-type ClC-5. Channel activity was similarly restored when complementary split channel constructs made for Dent's mutation R648 were coexpressed, but no ClC-5 currents were found when split channels for mutations R347, Y617, or R704 were coexpressed. Immunoblot and immunofluorescence studies of COS-7 cells revealed that N or C protein fragments could be transiently expressed and detected in the plasma membrane, even in split channels that failed to show functional activity. The results suggest that ClC-5 channel activity can be restored for specific Dent's mutations by expression of the missing portion of the ClC-5 molecule.

Lack of involvement of nucleotide excision repair gene polymorphisms in colorectal cancer

DNA repair has an essential role in protecting the genome from damage by endogenous and environmental agents. Polymorphisms in DNA repair genes and differences in repair capacity between individuals have been widely documented. For colorectal cancer, the loss of mismatch repair gene activity is a key genetic determinant. Nucleotide excision repair (NER), recombination repair (RR) and base excision repair (BER) pathways have critical roles in protection against other cancers, and we wished to investigate their role in colorectal cancer. We have compared the frequency of polymorphisms in the NER genes, XPD, XPF, XPG, ERCC1; in the BER gene, XRCC1; and in the RR gene, XRCC3; in colorectal cancer patients and in a control group. No significant associations were found for any of the NER gene polymorphisms or for the XRCC1 polymorphism. The C allele (position 18067) of the XRCC3 gene was weakly but significantly associated with colorectal cancer (odds ratio 1.52, 95% confidence interval 1.04-2.22, P=0.03). For all patients who were heterozygous for any of the repair genes studied, tumour tissue was investigated for loss of heterozygosity (LOH). Only one example of LOH was found for all the genes examined. From the association and LOH data, we conclude that these genes do not have an important role in protection against colorectal carcinogenesis.

Review of Ge detectors for gamma spectroscopy

A review is given of the use of germanium detectors for gamma spectroscopy. The advantages, principles of operation, and fabrication processes of semiconductor radiation detectors are described.

Expression and regulation of ClC-5 chloride channels: effects of antisense and oxidants

Genetic mutations of the Cl(-) channel ClC-5 cause Dent's disease in humans. We recently cloned an amphibian ortholog of Xenopus ClC-5 (xClC-5) from the A6 cell line. We now compare the properties and regulation of ClC-5 currents expressed in mammalian (COS-7) cells and Xenopus oocytes. Whole cell currents in COS-7 cells transfected with xClC-5 cDNA had strong outward rectification, Cl(-) > I(-) anion sensitivity, and were inhibited at low pH, similar to previous results in oocytes. In oocytes, antisense xClC-5 cRNA injection had no effect on endogenous membrane currents or the heterologous expression of human ClC-5. Activators of cAMP and protein kinase C inhibitors had no significant effects on ClC-5 currents expressed in either COS-7 cells or oocytes, whereas H-89, a cAMP-dependent protein kinase (PKA) inhibitor, and hydrogen peroxide decreased the currents. We conclude that the basic properties of ClC-5 currents were independent of the host cell type used for expression. In addition, ClC-5 channels may be modulated by PKA and reactive oxygen species.

The frequency of homozygous deletion of a developmentally regulated Vh gene (Humhv3005) is increased in patients with chronic idiopathic thrombocytopenic purpura

Little is known of the genetic factors that may contribute to the development of chronic idiopathic thrombocytopenic purpura (cITP). We have previously shown that a developmentally regulated Vh gene (Humhv3005) is absent in 10/41 (24%) of patients with systemic lupus erythematosus while it is absent in only 7/88 (8%) of normal controls. This finding suggests that a homozygous deletion of an Ig variable (V) gene may alter the immune system and thus predispose the host to an autoimmune disorder. We have analyzed the same gene in 44 patients with cITP and found that Humhv3005 and like genes were absent in a higher percentage of patients (14 of 44, 31.8%) than they were absent in either normals (7/88, 8%, p = 0.002) or thrombocytopenic patients without cITP (6/53, 11.3%, p = 0.042); the hv3005 deletion frequency in the latter group did not differ from that in normals (P = 0.74). These data suggest that deletions of Humhv3005 and/or highly homologous Vh genes may predispose individuals to the development of cITP, and may contribute toward production of pathogenic antiplatelet antibodies.

Anticardiolipin antibodies from patients with the antiphospholipid antibody syndrome recognize epitopes in both beta(2)-glycoprotein 1 and oxidized low-density lipoprotein

BACKGROUND

We recently suggested that many anticardiolipin antibodies bind only to oxidized cardiolipin (OxCL) and/or to OxCL-beta(2)-glycoprotein 1 (beta(2)GP1) adducts but not to a "reduced" cardiolipin that is unable to undergo oxidation. To test this hypothesis, we investigated 24 sera, 4 protein A-purified IgG fractions, and 3 human monoclonal antibodies that were all isolated from patients with antiphospholipid antibody syndrome (APS); testing was also performed in 7 controls. Two monoclonal antibodies (IS3 and IS4) were selected for binding to CL and one was selected for binding to beta(2)GP1 (LJB8).

METHODS AND RESULTS

By chemiluminescent immunoassay, all APS sera samples bound only to OxCL and not to reduced CL, and the binding was inhibited >95% by OxCL but not reduced CL. All purified IgG fractions bound to beta(2)GP1 but only when the beta(2)GP1 was plated on microtiter wells coated with OxCL. All 3 monoclonal antibodies bound only to OxCL. On Western blots, IS4 and LJB8 bound to beta(2)GP1 as well as to delipidated apoB of oxidized LDL but not to native apoB. IS3 also bound to oxidized apoB on Western blot. Covalent modification of beta(2)GP1 with oxidation products of CL made it more antigenic for APS serum samples, for purified IgG fractions, and for the monoclonal antibodies.

CONCLUSIONS

These data support the hypothesis that oxidation of CL is needed to generate epitopes for many anticardiolipin antibodies and that some of these epitopes are covalent adducts of OxCL with beta(2)GP1 or apoB.

Chloride channel expression in cultured human fetal RPE cells: response to oxidative stress

PURPOSE

The human fetal cell line RPE 28 SV4 has been useful for studies of oxidative stress and apoptosis in retinal pigmented epithelium. This cell model is now assessed in functional investigations of chloride channel activity. The study aims to determine the presence of specific chloride channels, including CFTR and ClC channels, to identify the properties of membrane chloride currents and to assess their modulation by hydrogen peroxide, cAMP, and other agents.

METHODS

Channel expression was determined using RT-PCR and cDNA cloning and biochemical and immunocytochemical methods. Membrane currents were analyzed using whole-cell, patch-clamp techniques.

RESULTS

RT-PCR results confirmed the presence of ClC-5 mRNA, and a full-length clone encoding ClC-3 was isolated from a cDNA library for RPE 28 SV4 cells. Specific staining for CFTR and several ClC channels was detected by immunocytochemistry. Whole-cell chloride currents (under conditions of symmetrical chloride concentrations) averaged 16.9 +/- 3.4 pA/pF (at +100 mV; n = 8), showed outward rectification, and had an anion permeability sequence of Cl(-) > I(-) > cyclamate. Currents were stimulated by cAMP cocktail (250 microM cAMP, 100 microM IBMX, and 25 microM forskolin) and were inhibited by 1 mM DIDS. The oxidative agent hydrogen peroxide (100 microM) decreased the current by 34% +/- 10% (n = 4). CONCLUSIONS. These findings suggest that RPE 28 SV4 cells possess regulated chloride channels including CFTR and members of the ClC chloride channel family. The inhibition of chloride currents by H(2)O(2) suggests that this cell line may be advantageous for studies of chloride channel modulation by oxidative stress.

[Detection of 8-hydroxyguanine in the DNA of the H2O2-treated HL-60 cells by GC/FID]

This paper describes the DNA damage by hydrogen peroxide in HL-60 cells and the detection of 8-hydroxyguanine produced. The number of cells was at least about 2 x 10(7)/sample. Treatment of HL-60 cells with 0.4 mmol/L hydrogen peroxide for 24 h would result in DNA damage. The DNA samples were isolated, then qualitatively and quantitatively analyzed before hydrolysis. The results of experiments showed that 100-300 microL 98% formic acid could hydrolyze about 0.12 mg DNA samples completely in 150 degrees C for 1 h. After lyophilizing the DNA samples for 6-8 h, one DNA sample was trimethylsilylated completely with 150 microL BSTFA in 150 degrees C for 1 h. The recovery of trimethylsilylated 8-hydroxyguanine was 81.70%. The trimethylsilylated 8-hydroxyguanine was identified by GC/FID and CGC/MS-SIM parallely.

[The effects of moderate acute normovolemic hemodilution on intestinal oxygen supply and consumption in anesthetized cats]

OBJECTIVE

To study the effects of moderate acute normovolemic hemodilution on the intestinal blood perfusion and oxygen supply in cats.

METHODS

15 domestic male cats were hemodiluted with Haemaccel. HR, MAP, lactate concentration in superior mesenteric vein (LAC), superior mesenteric artery blood flow (SMABF), superior mesenteric artery and venous blood gas analysis were recorded and the intestinal oxygen delivery (DO(2)), oxygen consumption (VO(2)) and oxygen extraction (EO(2)) were calculated before and after hemodilution.

RESULTS

SMABF increased obviously (P < 0.05), intestinal DO(2) and EO(2) did not change (P > 0.05) but VO(2) increased (P < 0.05), and LAC in superior mesenteric vein did not increase.

CONCLUSIONS

Moderate acute normovolemic hemodilution with Haemaccel do not alter intestinal oxygen delivery by increasing the superior mesenteric blood flow. It means that intestinal mucosa ischemia does not happen during moderate acute normovolemic hemodilution.

Comparison of amphibian and human ClC-5: similarity of functional properties and inhibition by external pH

Loss of function mutations of the renal chloride channel, ClC-5, have been implicated in Dent's disease, a genetic disorder characterized by low weight proteinuria, hypercalciuria, nephrolithasis and, in some cases, eventual renal failure. Recently, our laboratory used an RT-PCR/RACE cloning strategy to isolate an amphibian cDNA from the renal epithelial cell line A6 that had high homology to human ClC-5. We now report a full-length native ClC-5 clone (xClC-5, containing 5' and 3' untranslated regions) isolated by screening a cDNA library from A6 cells that was successfully expressed in Xenopus oocytes. In addition, we compared the properties of xClC-5 and hClC-5 using isogenic constructs of xClC-5 and hClC-5 consisting of the open reading frame subcloned into an optimized Xenopus expression vector. Expression of the full-length "native" xClC-5 clone resulted in large, strongly rectifying, outward currents that were not significantly affected by the chloride channel blockers DIDS, DPC, and 9AC. The anion conductivity sequence was NO-3 > Cl- = I- > HCO-3 >> glutamate for xClC-5 and NO-3 > Cl- > HCO-3 > I- >> glutamate for hClC-5. Reduction of the extracellular pH (pHo) from 7.5 to 5.7 inhibited outward ClC-5 currents by 27 +/- 9% for xClC-5 and 39 +/- 7% for hClC-5. The results indicate that amphibian and mammalian ClC-5 have highly similar functional properties. Unlike hClC-5 and most other ClC channels, expression of xClC-5 in oocytes does not require the removal of its untranslated 5' and 3' regions. Acidic solutions inhibited both amphibian and human ClC-5 currents, opposite to the stimulatory effects of low external pH on other ClC channels, suggesting a possibly distinct regulatory mechanism for ClC-5 channels.

[Comparison of the cytotoxicity of five constituents from Pteris semipinnata L. in vitro and the analysis of their structure-activity relationships]

The antitumor constituents were isolated from Pteris semipinnata L. (PsL), a Chinese traditional herb, and screened using tetrazolium salt (MTT) method. Their cytotoxic effects in vitro on several human tumor cell lines were studied. Compounds 5F, 6F, A and the ethanolic extract of PsL (PSE) were shown to have strong cytotoxicity against five cell lines: human liver adenocarcinoma cell line (HePG II), human lung adenocarcinom a cell line (SPC-A-1), human gastric adenocarcinoma cell line (MGC-803), human nasopharyngeal carcinoma cells in low differentiation (CNE-2Z) and human liver adenocarcinoma cell line (BEL-7402) in different degrees in a dose-dependent manner; compound 6F was the most active one, whose IC50 after 72 h treatment for the above five cell lines were 0.343 +/- 0.003, 0.115 +/- 0.022, 0.590 +/- 0.032, 0.328 +/- 0.066 and 0.221 +/- 0.058 microgram.ml-1, respectively. Compounds A and 5F were less active; no cytotoxicity of compounds 4F and B were detected on the five cell lines. Analysis of the relationship between structure and activity revealed that the antitumor activity portion in the structure is the alpha, beta-methylene cyclopentanone moiety, and the site and number of the hydroxy groups affect the cytotoxicity of these agents significantly.

[Study on the chemical components of Alpinia officinarum]

Four crystalline substances were isolated from rhizome of Alpinia officinarum Hance. They were identified as beta-Sitosterol (I), Galangin (II), Emodin (III) and Quercetin (IV), I and III were separated from this plant for the first time.