Theta oscillons in behaving rats

Recently discovered constituents of the brain waves-the oscillons -provide high-resolution representation of the extracellular field dynamics. Here we study the most robust, highest-amplitude oscillons that manifest in actively behaving rats and generally correspond to the traditional θ -waves. We show that the resemblances between θ -oscillons and the conventional θ -waves apply to the ballpark characteristics-mean frequencies, amplitudes, and bandwidths. In addition, both hippocampal and cortical oscillons exhibit a number of intricate, behavior-attuned, transient properties that suggest a new vantage point for understanding the θ -rhythms' structure, origins and functions. We demonstrate that oscillons are frequency-modulated waves, with speed-controlled parameters, embedded into a noise background. We also use a basic model of neuronal synchronization to contextualize and to interpret the observed phenomena. In particular, we argue that the synchronicity level in physiological networks is fairly weak and modulated by the animal's locomotion.

Theta oscillons in behaving rats

Recently discovered constituents of the brain waves-the oscillons-provide high-resolution representation of the extracellular field dynamics. Here we study the most robust, highest-amplitude oscillons that manifest in actively behaving rats and generally correspond to the traditional θ -waves. We show that the resemblances between θ -oscillons and the conventional θ -waves apply to the ballpark characteristics-mean frequencies, amplitudes, and bandwidths. In addition, both hippocampal and cortical oscillons exhibit a number of intricate, behavior-attuned, transient properties that suggest a new vantage point for understanding the θ -rhythms' structure, origins and functions. We demonstrate that oscillons are frequency-modulated waves, with speed-controlled parameters, embedded into a noise background. We also use a basic model of neuronal synchronization to contextualize and to interpret the observed phenomena. In particular, we argue that the synchronicity level in physiological networks is fairly weak and modulated by the animal's locomotion.

A phosphamide nucleotide analog: a substrate for polymerase synthesis of DNA

A type of modified nucleotide, deoxynucleotide γ-amidotriphosphates (dNTPγNH2s), exhibited around five times higher stability than dNTPs. These phosphamide nucleotides can be utilized by several DNA polymerases, and the amplification of a 10 kb DNA fragment through the polymerase chain reaction (PCR) can be accomplished even under conditions of high temperature, extended storage, or repeated freeze-thaw cycles. However, the control PCR with standard dNTPs was unsuccessful. These results indicate that dNTPγNH2s have the potential to substitute dNTPs in PCR.

Altered patterning of neural activity in a tauopathy mouse model

Alzheimer's disease (AD) is a complex neurodegenerative condition that manifests at multiple levels and involves a spectrum of abnormalities ranging from the cellular to cognitive. Here, we investigate the impact of AD-related tau-pathology on hippocampal circuits in mice engaged in spatial navigation, and study changes of neuronal firing and dynamics of extracellular fields. While most studies are based on analyzing instantaneous or time-averaged characteristics of neuronal activity, we focus on intermediate timescales-spike trains and waveforms of oscillatory potentials, which we consider as single entities. We find that, in healthy mice, spike arrangements and wave patterns (series of crests or troughs) are coupled to the animal's location, speed, and acceleration. In contrast, in tau-mice, neural activity is structurally disarrayed: brainwave cadence is detached from locomotion, spatial selectivity is lost, the spike flow is scrambled. Importantly, these alterations start early and accumulate with age, which exposes progressive disinvolvement the hippocampus circuit in spatial navigation. These features highlight qualitatively different neurodynamics than the ones provided by conventional analyses, and are more salient, thus revealing a new level of the hippocampal circuit disruptions.

Phase I dose escalation and expansion study of golidocitinib, a highly selective JAK1 inhibitor, in relapsed or refractory peripheral T-cell lymphomas

BACKGROUND

Relapsed or refractory peripheral T-cell lymphomas (r/r PTCLs) are a group of rare and aggressive diseases that lack effective therapies. Constitutive activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway is reported to be associated with PTCLs. Golidocitinib is an oral, potent JAK1 selective inhibitor evaluated in a phase I/II multinational study in patients with r/r PTCLs.

PATIENTS AND METHODS

Patients with r/r PTCLs were eligible. The primary objectives were to assess safety and tolerability of golidocitinib and to define its recommended phase II dose (RP2D). The secondary objectives were to evaluate its antitumor activity and pharmacokinetics (PK).

RESULTS

A total of 51 patients were enrolled and received golidocitinib treatment at 150 or 250 mg once daily (QD). The median prior lines of therapies were 2 (range: 1-8). Golidocitinib was tolerated at both doses tested, while a higher incidence of serious adverse events and dose modifications at 250 mg were observed. The most common grade ≥3 drug-related treatment-emergent adverse events were neutropenia (27.5%) and thrombocytopenia (11.8%). An objective response rate of 39.2% and a complete response rate of 21.6% were observed. With median follow-up time of 14.7 and 15.9 months, the median duration of response (DoR) and progression-free survival were 8.0 and 3.3 months, respectively. Based on these data, 150 mg QD was defined as the RP2D. Golidocitinib demonstrated a favorable PK profile as an oral agent. Biomarker analysis suggested a potential correlation between JAK/STAT pathway aberrations and clinical activity of golidocitinib.

CONCLUSIONS

In this phase I study, golidocitinib demonstrated an acceptable safety profile and encouraging antitumor efficacy in heavily pretreated patients with r/r PTCLs. These results support the initiation of the multinational pivotal study in patients with r/r PTCLs.

Integration of Activation by Hypoxia and Inhibition Resistance of Tumor Cells to Apoptosis for Precise and Augmented Photodynamic Therapy

Photodynamic therapy (PDT) uses photosensitizers to convert oxygen (O2 ) to reactive oxygen species (ROS) under irradiation to induce DNA damage and kill cancer cells. However, the effect of PDT is usually alleviated by apoptosis resistance mechanism of tumor living cells. MTH1 enzyme is known to be such an apoptosis-resistance enzyme which is over expressed as a scavenger to repair the damaged DNA. In this work, a hypoxia-activated nanosystem FTPA, which can be degraded to release the encapsulated PDT photosensitizer 4-DCF-MPYM and an inhibitor TH588 is proposed. The inhibitor TH588 can inhibit the DNA repair process by reducing the activity of MTH1 enzyme, and achieve the purpose of amplifying the therapeutic effect of PDT. This work demonstrates that a precise and augmented tumor PDT is achieved by integration of hypoxia-activation and inhibition resistance of tumor cells to apoptosis.

Efficient capture of uranium by a hydroxyapatite-modified polyethyleneimine@carbon nanotube composite from radioactive nuclear waste

The toxicity and radioactivity of uranium (U)-containing wastewater pose a serious threat to the environment of humans, animals, and plants. It is necessary to remove U from contaminated wastewater. With high adsorption capacity and fast adsorption rate, a composite CNT-P/HAP, which comprises carbon nanotubes (CNT) modified with polyethyleneimine (PEI), was functionalized further by hydroxyapatite (HAP) using the hydrothermal method. Adsorption experiments indicated that the optimal performance for CNT-P/HAP was 1330.64 mg g^-1 of adsorption capacity and 40 min of adsorption equilibrium at a pH of 3. In addition, the adsorption capacity of CNT-P/HAP was over 2 times that of HAP at a pH of 7. The synergistic effect in both synthesis and adsorption gave CNT-P/HAP an excellent adsorption capacity for U. The XRD and FT-IR analysis indicated that the adsorption mechanism of CNT-P/HAP for U is decided by the pH of the solution. CNT-P/HAP could be used in multiple conditions to remediate U-containing wastewater.

Suvemcitug as second-line treatment of advanced or metastatic solid tumors and with FOLFIRI for pretreated metastatic colorectal cancer: phase Ia/Ib open label, dose-escalation trials

BACKGROUND

Suvemcitug (BD0801), a novel humanized rabbit monoclonal antibody against vascular endothelial growth factor, has demonstrated promising antitumor activities in preclinical studies.

PATIENTS AND METHODS

The phase Ia/b trials investigated the safety and tolerability and antitumor activities of suvemcitug for pretreated advanced solid tumors and in combination with FOLFIRI (leucovorin and fluorouracil plus irinotecan) in second-line treatment of metastatic colorectal cancer using a 3 + 3 dose-escalation design. Patients received escalating doses of suvemcitug (phase Ia: 2, 4, 5, 6, and 7.5 mg/kg; phase Ib: 1, 2, 3, 4, and 5 mg/kg plus FOLFIRI). The primary endpoint was safety and tolerability in both trials.

RESULTS

All patients in the phase Ia trial had at least one adverse event (AE). Dose-limiting toxicities included grade 3 hyperbilirubinemia (one patient), hypertension and proteinuria (one patient), and proteinuria (one patient). The maximum tolerated dose was 5 mg/kg. The most common grade 3 and above AEs were proteinuria (9/25, 36%) and hypertension (8/25, 32%). Forty-eight patients (85.7%) in phase Ib had grade 3 and above AEs, including neutropenia (25/56, 44.6%), reduced leucocyte count (12/56, 21.4%), proteinuria (10/56, 17.9%), and elevated blood pressure (9/56, 16.1%). Only 1 patient in the phase Ia trial showed partial response, [objective response rate 4.0%, 95% confidence interval (CI) 0.1% to 20.4%] whereas 18/53 patients in the phase Ib trial exhibited partial response (objective response rate 34.0%, 95% CI 21.5% to 48.3%). The median progression-free survival was 7.2 months (95% CI 5.1-8.7 months).

CONCLUSIONS

Suvemcitug has an acceptable toxicity profile and exhibits antitumor activities in pretreated patients with advanced solid tumors or metastatic colorectal cancer.

Enhancing Repair of Oxidative DNA Damage with Small-Molecule Activators of MTH1

Impaired DNA repair activity has been shown to greatly increase rates of cancer clinically. It has been hypothesized that upregulating repair activity in susceptible individuals may be a useful strategy for inhibiting tumorigenesis. Here, we report that selected tyrosine kinase (TK) inhibitors including nilotinib, employed clinically in the treatment of chronic myeloid leukemia, are activators of the repair enzyme Human MutT Homolog 1 (MTH1). MTH1 cleanses the oxidatively damaged cellular nucleotide pool by hydrolyzing the oxidized nucleotide 8-oxo-2'-deoxyguanosine (8-oxo-dG)TP, which is a highly mutagenic lesion when incorporated into DNA. Structural optimization of analogues of TK inhibitors resulted in compounds such as SU0448, which induces 1000 ± 100% activation of MTH1 at 10 μM and 410 ± 60% at 5 μM. The compounds are found to increase the activity of the endogenous enzyme, and at least one (SU0448) decreases levels of 8-oxo-dG in cellular DNA. The results suggest the possibility of using MTH1 activators to decrease the frequency of mutagenic nucleotides entering DNA, which may be a promising strategy to suppress tumorigenesis in individuals with elevated cancer risks.

[Berberine inhibits erastin-induced ferroptosis of mouse hippocampal neuronal cells possibly by activating the Nrf2-HO-1/GPX4 pathway]

OBJECTIVE

To explore the mechanism by which berberine inhibits ferroptosis of mouse hippocampal neuronal cells (HT22).

METHODS

Cultured HT22 cells were pretreated with 30 or 60 μmol/L berberine for 2 h before exposure to 0.5 μmol/L erastin for 8 h, and the cell proliferation, intracellular ferric iron level, changes in intracellular reactive oxygen species (ROS) and cell apoptosis were detected using CCK-8, Fe²⁺ fluorescent probe, fluorescent dye (DAPI) and fluorescent probe (H2DCFH-DA). RT-qPCR and Western blotting were used to detect the mRNA and protein expressions of Nrf2, HO-1 and GPX4 in the cells. We further tested the effects of treatments with 2 μmol/L ML385 (a Nrf2 inhibitor), 60 μmol/L berberine and erastin in the cells to explore the protective mechanism of berberine against erastin-induced ferroptosis in the neuronal cells.

RESULTS

Treatment with 0.5 μmol/L erastin significantly lowered the viability of HT22 cells (P < 0.05) and increased the production of ROS, cell apoptosis rate and ferric iron level (P < 0.05). Pretreatment with 30 and 60 μmol/L berberine both significantly increased the vitality of erastin-exposed cells (P < 0.05) and lowered the levels of intracellular ROS and ferric iron content (P < 0.05). RT-qPCR and Western blotting showed that berberine obviously promoted the expressions of Nrf2, HO-1 and GPX4 in the cells (P < 0.05), and treatment with ML385 significantly inhibited the Nrf2-HO-1/GPX4 pathway, increased intracellular ROS and ferric iron contents and mitigated the protective effect of berberine against erastin-induced ferroptosis (P < 0.05).

CONCLUSION

Berberine can inhibit erastin-induced ferroptosis in HT22 cells possibly by activating the Nrf2-HO-1/ GPX4 pathway.

The role of inflammation and cortisol in the relationship between social cognition abilities and later emotional or behavioural problems: evidence from a UK birth cohort

Introduction

Deficits in social cognition have been associated with the onset of emotional and behavioural problems, but the biological mechanisms underlying this relationship remain unclear.

Objectives

This study examined whether diurnal cortisol patterns, systemic inflammation, or both, explained the association between social cognition difficulties and subsequent emotional and behavioural symptoms.

Methods

The sample consisted of 714 individuals from the Avon Longitudinal Study of Parents and Children (ALSPAC) with valid data on cortisol measures (age 15 years) and emotional or behavioural problems (age 17 years). Social cognition abilities were measured at 8, 11, and 14 years old. Inflammation was measured using serum levels of interleukin 6 (IL-6, age 9 years) and C-reactive protein (CRP, age 9 and 16 years). Bayesian structural equation modelling was used to investigate the mediating effect of cortisol or inflammation on the association between social cognitive difficulties and emotional or behavioural problems.

Results

Children with social cognition difficulties were associated with later emotional and behavioural problems. Flattened diurnal cortisol slope was associated with the hyperactivity/inattention problem two years later. Mediation analyses revealed that lower morning cortisol significantly mediated the associations between social communication difficulties at 8 years with hyperactivity/inattention and conduct problems in adolescence, with the adjustment of inflammation and all covariates. Systemic inflammation was not related to social cognitive difficulties or future emotional and behavioural problems.

Conclusions

The finding suggests that social cognition is related to cortisol activities longitudinally. It also expands the evidence that adolescents with behavioural problems are characterised by hypoactivity of the hypothalamic-pituitary-adrenal (HPA) axis.

Disclosure

No significant relationships.

[The in vivo imaging of zebrafish for chemical vascular toxicity assessment]

Objective: To evaluate the vascular toxicity of chemicals by a real-time observation approach using the transgenic zebrafish. Methods: The spatiotemporal vascular alterations of transgenic zebrafish after chemical exposure were assessed by laser confocal microscopy and high-content screening analysis, respectively. Results: The method using Laser Confocal Microscopy (LCM) is easier to operate and yields high-resolution images, while it is lower throughput and inefficient. In contrast, high-content analysis (HCA) analysis obtains high-quality data of vascular toxicity manifesting whole blood vasculature, whereas it requires delicate operation procedures and advanced experimental conditions. Conclusion: Two kinds of zebrafish imaging methods each have advantages and disadvantages. LCM is suitable for the evaluation of a small number of chemicals. HCA, a cutting-edge technology, has great potential for chemical safety assessment allowing high throughput vascular toxicity tests of a good number of chemicals at a time.

Removal of uranium from wastewater through Ni-Al-layered double hydroxide@carbon nanotube functionalized by polyethyleneimine

Nuclear energy is widely used as efficient energy. However, the production of a large amount of uranium-containing wastewater is considerably harmful to the environment. Adsorption is a commonly used method...

Luminescence method for detection of aflatoxin B1 using ATP-releasing nucleotides

Determination of aflatoxin B1 (AFB1) is still a big issue in food safety. In this paper, we developed a luminescence AFB1 detection method combined with ATP-releasing nucleotides (ARNs) and AFB1 aptamer. Firstly, using a new coupling method, we synthesized two ARNs (dTP₄A and dGP₄A) in a yield of 67% and 58%, respectively. The newly prepared ARNs show a much lower background. Then, we developed a new isothermal polymerase amplification method. In this method, two DNA hairpins were used to substitute the circle DNA template in rolling circle amplification. Using this amplification method and combined with AFB1 aptamer, a new AFB1 detection method is developed. A detection limit as low as 0.3 pM is achieved. This method is simple and efficient, and will have a great potential to be used for food safety and public health.

Schematic illustration of a luminescence short DNA sequence detection method using ATP-releasing nucleotides. Combined with AFB1 aptamer, this method is used to detect AFB1.

Coverage and effectiveness of hypertension screening in different altitudes of Tibet autonomous region

BACKGROUND

Tibet is an autonomous region in China located around an average altitude of 4500 m above sea level. Since 2012 the local government of Tibet has been providing free physical examinations, including screening for hypertension. However, the coverage and effectiveness of this free program have not been uncovered. This study aims to assess the coverage and effectiveness of hypertension screening and management program in 3 altitude levels of Tibet, and also the determinants of the success of the screening program.

METHODS

A stratified cluster survey was conducted among 1636 residents aged 18 years or over in three different altitude areas in Tibet. We adjusted for age and sex based on national census data and used weighted logistic regression models to find factors associated with hypertension screening.

RESULTS

The coverage of the hypertension screening program evaluated by participation rate in the previous screening was 94.9%, while 24.7% (95% CI: 22.1-27.3%) of them were diagnosed with hypertension. Females and alcohol drinkers were more likely to be screened. Among those diagnosed with hypertension, 28.7% had it under control. High altitude areas had a high proportion of controlled hypertension. The overall rate of controlled hypertension in high, moderate and low altitude areas was 35.1% (95% CI: 24.8-45.3%), 32.7% (95% CI: 22.2-43.2%) and 23.7% (95% CI: 14.7-32.6%), respectively. Younger aged persons were more likely to have better control of their hypertension.

CONCLUSIONS

The coverage of hypertension screening in Tibet was high, especially in the low altitude areas. However, the effectiveness of hypertension control was low, indicating a need to implement the treatment adherence routines into the current screening interventions.

Polymerase synthesis of four-base DNA from two stable dimeric nucleotides

We document the preparation and properties of dimerized pentaphosphate-bridged deoxynucleotides (dicaptides) that contain reactive components of two different nucleotides simultaneously. Importantly, dicaptides are found to be considerably more stable to hydrolysis than standard dNTPs. Steady-state kinetics studies show that the dimers exhibit reasonably good efficiency with the Klenow fragment of DNA polymerase I, and we identify thermostable enzymes that process them efficiently at high temperature. Experiments show that the dAp₅dT dimer successfully acts as a combination of dATP and dTTP in primer extension reactions, and the dGp₅dC dimer as a combination of dGTP and dCTP. The two dimers in combination promote successful 4-base primer extension. The final byproduct of the reaction, triphosphate, is shown to be less inhibitory to primer extension than pyrophosphate, the canonical byproduct. Finally, we document PCR amplification of DNA with two dimeric nucleotides, and show that the dimers can promote amplification under extended conditions when PCR with normal dNTPs fails. These dimeric nucleotides represent a novel and simple approach for increasing stability of nucleotides and avoiding inhibition from pyrophosphate.

Determination of Campesterol, Stigmasterol, and Beta-Sitosterol in Saw Palmetto Raw Materials and Dietary Supplements by Gas Chromatography: Collaborative Study

An interlaboratory study was conducted to evaluate a method for the determination of campesterol, stigmasterol, and beta-sitosterol in saw palmetto raw materials and dietary supplements at levels &gt;1.00 mg/100 g based on a 23 g sample. Test samples were saponified at high temperature with ethanolic KOH solution. The unsaponifiable fraction containing phytosterols (campesterol, stigmasterol, and beta-sitosterol) was extracted with toluene. Phytosterols were derivatized to trimethylsilyl ethers and then quantified by gas chromatography with hydrogen flame ionization detection. Twelve blind duplicates, one of which was fortified, were successfully analyzed by 10 collaborators. Recoveries were obtained for the sample that was fortified. The results were 99.8, 111, and 111% for campesterol, stigmasterol, and beta-sitosterol, respectively. For repeatability, the relative standard deviation (RSDr) ranged from 3.93 to 17.3% for campesterol, 3.56 to 22.7% for stigmasterol, and 3.70 to 43.9% for beta-sitosterol. For reproducibility, the RSDR ranged from 7.97 to 22.6%, 0 to 26.7%, and 5.27 to 43.9% for campesterol, stigmasterol, and beta-sitosterol, respectively. Overall, the Study Director approved 5 materials with acceptable HorRat values for campesterol, stigmasterol, and beta-sitosterol ranging from 1.02 to 2.16.

Determination of β-Carotene in Supplements and Raw Materials by Reversed-Phase High Pressure Liquid Chromatography: Collaborative Study

Twelve laboratories representing 4 countries participated in an interlaboratory study conducted to determine all-trans-β-carotene and total β-carotene in dietary supplements and raw materials. Thirteen samples were sent as blind duplicates to the collaborators. Results obtained from 11 laboratories are reported. For products composed as softgels and tablets that were analyzed for total β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 3.35 to 23.09% and the HorRat values ranged from 1.06 to 3.72. For these products analyzed for trans β-carotene, the reproducibility relative standard deviation (RSDR) ranged from 4.28 to 22.76% and the HorRat values ranged from 0.92 to 3.37. The RSDr and HorRat values in the analysis of a beadlet raw material were substantial and it is believed that the variability within the material itself introduced significant variation in subsampling. The method uses high pressure liquid chromatography (LC) in the reversed-phase mode with visible light absorbance for detection and quantitation. If high levels of α-carotenes are present, a second LC system is used for additional separation and quantitation of the carotene species. It is recommended that the method be adopted as an AOAC Official Method.

The Existence of MTH1-independent 8-oxodGTPase Activity in Cancer Cells as a Compensatory Mechanism against On-target Effects of MTH1 Inhibitors

Investigations into the human 8-oxodGTPase, MutT Homolog 1 (MTH1), have risen sharply since the first-in-class MTH1 inhibitors were reported to be highly tumoricidal. However, MTH1 as a cancer therapeutic target is currently controversial because subsequently developed inhibitors did not exhibit similar cytotoxic effects. Here, we provide the first direct evidence for MTH1-independent 8-oxodGTPase function in human cancer cells and human tumors, using a novel ATP-releasing guanine-oxidized (ARGO) chemical probe. Our studies show that this functionally redundant 8-oxodGTPase activity is not decreased by five different published MTH1-targeting small molecules or by MTH1 depletion. Significantly, while only the two first-in-class inhibitors, TH588 and TH287, reduced cancer cell viability, all five inhibitors evaluated in our studies decreased 8-oxodGTPase activity to a similar extent. Thus, the reported efficacy of the first-in-class MTH1 inhibitors does not arise from their inhibition of MTH1-specific 8-oxodGTPase activity. Comparison of DNA strand breaks, genomic 8-oxoguanine incorporation, or alterations in cellular oxidative state by TH287 versus the noncytotoxic inhibitor, IACS-4759, contradict that the cytotoxicity of the former results solely from increased levels of oxidatively damaged genomic DNA. Thus, our findings indicate that mechanisms unrelated to oxidative stress or DNA damage likely underlie the reported efficacy of the first-in-class inhibitors. Our study suggests that MTH1 functional redundancy, existing to different extents in all cancer lines and human tumors evaluated in our study, is a thus far undefined factor which is likely to be critical in understanding the importance of MTH1 and its clinical targeting in cancer.

Increased MTH1-specific 8-oxodGTPase activity is a hallmark of cancer in colon, lung and pancreatic tissue

Cellular homeostasis is dependent on a balance between DNA damage and DNA repair mechanisms. Cells are constantly assaulted by both exogenous and endogenous stimuli leading to high levels of reactive oxygen species (ROS) that cause oxidation of the nucleotide dGTP to 8-oxodGTP. If this base is incorporated into DNA and goes unrepaired, it can result in G > T transversions, leading to genomic DNA damage. MutT Homolog 1 (MTH1) is a nucleoside diphosphate X (Nudix) pyrophosphatase that can remove 8-oxodGTP from the nucleotide pool before it is incorporated into DNA by hydrolyzing it into 8-oxodGMP. MTH1 expression has been shown to be elevated in many cancer cells and is thought to be a survival mechanism by which a cancer cell can stave off the effects of high ROS that can result in cell senescence or death. It has recently become a target of interest in cancer because it is thought that inhibiting MTH1 can increase genotoxic damage and cytotoxicity. Determining the role of MTH1 in normal and cancer cells is confounded by an inability to reliably and directly measure its native enzymatic activity. We have used the chimeric ATP-releasing guanine-oxidized (ARGO) probe that combines 8-oxodGTP and ATP to measure MTH1 enzymatic activity in colorectal cancer (CRC), non-small cell lung cancer (NSCLC) and pancreatic ductal adenocarcinoma (PDAC) along with patient-matched normal tissue. MTH1 8-oxodGTPase activity is significantly increased in tumors across all three tissue types, indicating that MTH1 is a marker of cancer. MTH1 activity measured by ARGO assay was compared to mRNA and protein expression measured by RT-qPCR and Western blot in the CRC tissue pairs, revealing a positive correlation between ARGO assay and Western blot, but little correlation with RT-qPCR in these samples. The adoption of the ARGO assay will help in establishing the level of MTH1 activity in model systems and in assessing the effects of MTH1 modulation in the treatment of cancer.

A Novel AMELX Mutation, Its Phenotypic Features, and Skewed X Inactivation

Amelogenesis imperfecta (AI) is a group of genetic disorders of defective dental enamel. Mutation of AMELX encoding amelogenin on the X chromosome is a major cause of AI. Here we report a Chinese family with hypoplastic and hypomineralized AI. Whole exome analysis revealed a novel mutation c.185delC in exon 5 of AMELX causing the frame shift p.Pro62ArgfsTer47 (or p.Pro62Argfs*47). By sequencing of polymerase chain reaction products and T-vector clones, the mutation was confirmed as homozygous in the proband, hemizygous in her father, and heterozygous in her mother. The proband and her father had small and yellowish teeth with thin and rough enamel that was radiographically indistinguishable from the underlying dentin. Scanning electronic microscopy of 1 maternal tooth showed cracks and exposed loosely packed enamel prisms in affected areas. Consistent with a 25:75 skewing of X inactivation in the peripheral blood DNA as measured by androgen receptor allele methylation, the surface of the mother’s tooth had alternating vertical ridges of transparent normal and white chalky enamel in a 34:66 ratio. In summary, this study provides one of the few phenotypic comparisons of hemizygous and homozygous AMELX mutations and suggests that the skewing of X inactivation in AI contributes to the phenotypic variations in heterozygous carriers of X-linked AI.

Polymerase-amplified release of ATP (POLARA) for detecting single nucleotide variants in RNA and DNA

The identification of single nucleotide polymorphisms (SNP) is increasingly important for diagnosis and treatment of disease. Here we studied the potential use of ATP-releasing nucleotides (ARNs) for identifying SNPs in DNA and RNA targets. Synthesized as derivatives of the four canonical deoxynucleotides, ARNs can be used in the place of deoxynucleoside triphosphates to elongate a primer hybridized to a nucleic acid template, with the leaving group being ATP rather than pyrophosphate. The released ATP is then harnessed in conjunction with luciferase to generate chemiluminescence. Extension on a long target DNA or RNA generates many equivalents of ATP per target strand, providing isothermal amplification of signal. In principle, allele-specific primers could be used in conjunction with ARNs to generate differential luminescence signals with respect to distinct genetic polymorphisms. To test this, varied primer designs, modifications, enzymes and conditions were tested, resulting in an optimized strategy that discriminates between differing nucleic acid templates with single nucleotide resolution. This strategy was then applied to diagnostically relevant alleles resulting in discrimination between known polymorphisms. SNP detection was successfully performed on transcribed mRNA fragments from four different alleles derived from JAK2, BCR-ABL1, BRAF, and HBB. To investigate background interference, wild-type and mutant transcripts of these four alleles were tested and found to be easily distinguishable amid total cellular RNA isolated from human blood. Thus, ARNs have been employed with specialized allele-specific primers to detect diagnostically important SNPs in a novel method that is sensitive, rapid, and isothermal.

[The prevalence of allergy-related symptoms and their risk factorinvestigation in early life]

Objective:The aim of this study is to investigate the incidence of allergy-related symptoms and the associated risk factors.Method:There were 205 children aged 3 to 4 years old recruited for this study.Questionnaires on skin,wheezing and rhinitis symptoms were answered,and total IgE and specific IgE in serum against house dust mite extracts were tested.Logistic regression analysis with which we calculated odds ratio(OR) and 95% confidence interval(95%CI) were used for risk factor analysis.Result:Questionnaire results show that the reported history of symptoms was 43%(88 cases) for lactation eczema and 25%(51 cases) for wheezing.The currently reported symptoms was 19%(38 cases) for frequent skin rashes,16% (33 cases) for frequent wheezing and 46%(95 cases) for rhinitis symptoms.There are 33% (68 cases) of the children reported with no symptoms currently.The lactation eczema history(OR［95%CI］:2.76［1.10-3.40］,P<0.05)and wheezing history(OR［95%CI］:2.40［1.22-4.73］,P<0.01)are both the risk factors for developing rhinitis symptoms.Serology test shows that house dust mite IgE prevalence is 24%,which is the risk factor developing rhinitis symptom(OR［95%CI］:2.10［1.09-4.07］,P<0.05).But it has nothing to do with wheezing symptom.Conclusion:Lactation eczema and house dust mite sensitization are the risk factors for developing respiratory diseases in early childhood.The house dust mite allergic respiratory symptom starts with rhinitis symptom.

ATP-Linked Chimeric Nucleotide as a Specific Luminescence Reporter of Deoxyuridine Triphosphatase

Nucleotide surveillance enzymes play important roles in human health, by monitoring damaged monomers in the nucleotide pool and deactivating them before they are incorporated into chromosomal DNA or disrupt nucleotide metabolism. In particular, deamination of cytosine, leading to uracil in DNA and in the nucleotide pool, can be deleterious, causing DNA damage. The enzyme deoxyuridine triphosphatase (dUTPase) is currently under study as a therapeutic and prognostic target for cancer. Measuring the activity of this enzyme is important both in basic research and in clinical applications involving this pathway, but current methods are nonselective, detecting pyrophosphate, which is produced by many enzymes. Here we describe the design and synthesis of a dUTPase enzyme-specific chimeric dinucleotide (DUAL) that replaces the pyrophosphate leaving group of the native substrate with ATP, enabling sensitive detection via luciferase luminescence signaling. The DUAL probe functions sensitively and selectively to quantify enzyme activities in vitro and in cell lysates. We further report the first measurements of dUTPase activities in eight different cell lines, which are found to vary by a factor of 7-fold. We expect that the new probe can be of considerable utility in research involving this clinically significant enzyme.

Potent and Selective Inhibitors of 8-Oxoguanine DNA Glycosylase

The activity of DNA repair enzyme 8-oxoguanine DNA glycosylase (OGG1), which excises oxidized base 8-oxoguanine (8-OG) from DNA, is closely linked to mutagenesis, genotoxicity, cancer, and inflammation. To test the roles of OGG1-mediated repair in these pathways, we have undertaken the development of noncovalent small-molecule inhibitors of the enzyme. Screening of a PubChem-annotated library using a recently developed fluorogenic 8-OG excision assay resulted in multiple validated hit structures, including selected lead hit tetrahydroquinoline 1 (IC50 = 1.7 μM). Optimization of the tetrahydroquinoline scaffold over five regions of the structure ultimately yielded amidobiphenyl compound 41 (SU0268; IC50 = 0.059 μM). SU0268 was confirmed by surface plasmon resonance studies to bind the enzyme both in the absence and in the presence of DNA. The compound SU0268 was shown to be selective for inhibiting OGG1 over multiple repair enzymes, including other base excision repair enzymes, and displayed no toxicity in two human cell lines at 10 μM. Finally, experiments confirm the ability of SU0268 to inhibit OGG1 in HeLa cells, resulting in an increase in accumulation of 8-OG in DNA. The results suggest the compound SU0268 as a potentially useful tool in studies of the role of OGG1 in multiple disease-related pathways.

Significant Decrease in Dialysate Albumin Concentration during Molecular Adsorbent Recirculating System (M.A.R.S.) Therapy

Aim

The molecular adsorbent recirculating system (M.A.R.S.) is widely used as liver support therapy in patients with hepatic dysfunction. The goal of this study was to measure changes in dialysate albumin and bilirubin concentrations during clinical MARS treatments.

Methods

Eight patients with acute liver dysfunction and hyperbilirubinemia were enrolled in this study. Five of them received a total of 10 treatments with MARS, in which 600 mL of 20% human albumin was used as dialysate, continuously regenerated by two adsorbent columns in the circuit. Three patients received 4 treatments of a modified MARS, in which the two adsorbent columns were bypassed in the first course for 4 h, and then connected to the circuit in the second course for another 4 h. The total, conjugated and unconjugated bilirubin (TB, CB, UCB) and albumin concentrations in serum and albumin dialysate were dynamically measured, and the adsorbent column inlet pressures were recorded during each session. In one session, dialysate albumin levels were measured during the priming process, at the time points prior to the priming process, immediately after priming, and at the end of the treatment.

Results

During MARS therapies, the reduction ratio of serum TB, CB and UCB was 26.6±9.0%, 29.5±9.6% and 14.8±12.3%, respectively. The molar ratio of TB/albumin in serum was approximately 20-fold higher than dialysate at all time points. A significant albumin concentration decrease from baseline in the dialysate was found (mean±SD, 34.6±16.6%). For the first four hours of modified treatments, in which only albumin dialysis without albumin regeneration by adsorbent columns was performed, the dialysate albumin decrease was substantially smaller (mean, 8.3±1.5%). After switching to standard MARS, there was a further decrease in the dialysate albumin concentration of 35.1±14.5%. In one session, dialysate albumin concentrations were measured during the priming process, and levels decreased from 196.9 g/L to 144.4 g/L. Adsorber inlet pressure increased from 40±10mmHg at the start of priming to 150±50mmHg at the end of priming, and further increased to 340±100mmHg at the end of treatment.

Conclusion

There is a significant reduction in dialysate albumin concentration during MARS therapy. Binding of albumin to the adsorbent columns used for albumin regeneration is largely responsible for this decrease.

Improvement of Monocyte Secretion Function in a Porcine Pancreatitis Model by Continuous Dose-Dependent Veno-Venous Hemofiltration

Objective

Monocyte and its secreted cytokines play a crucial role in the process of severe acute pancreatitis (SAP). It has been known that continuous veno-venous hemofiltration (CVVH) can partially attenuate the inflammatory process by removal of cytokines, but the effect of CVVH on monocyte secretion function remains unknown. This study investigated the effect of different doses of CVVH on monocyte secretion function as well as the plasma cytokine profile in a SAP porcine model.

Methods

After successful induction of SAP by pressure-controlled (100 mmHg), intraductal injection of sodium taurocholate (4%, 1 ml/kg) and trypsin (2 U/kg), 24 swine were randomly assigned to 3 groups. Swine in group I (n=8) serving as SAP controls received only standard medical therapy (SMT). Besides SMT, swine in two other groups received zero-balanced CVVH, one hour after the induction of SAP, with low volume fluid exchange (group II, n=8, ultrafiltration rate (UFR) 20 ml/kg/h, LV-CVVH) or high volume (group III, n=8, UFR 100 ml/kg/h, HV-CVVH). Using heparin as anticoagulant, the filter (AN69, Hospal, Lyon, France) was changed every 24 hours. Monocytes were isolated from porcine blood at various timepoints for detection of cytokine secretion (interleukin-6, IL-6; interleukin-10, IL-10; tumor necrosis-α, TNF-α) after LPS stimulus; plasma cytokines were measured simultaneously.

Results

CVVH showed a dose-dependent beneficial effect on the animals’ survival time. In control animals, plasma pro-inflammatory cytokine levels exhibited a double-phase fluctuation after SAP induction: IL-6 and TNF-α rapidly increased to a peak level within 6–12 hours, then dropped to very low level in the late stage. Unlike pro-inflammatory cytokines, the plasma level of anti-inflammatory cytokine IL-10 reached a plateau within 6–12 hours but dropped little. In CVVH-treated animals, the peak-nadir patterns of 3 cytokines were all flattened, most prominently in the HV-CVVH group. Similarly to plasma cytokine patterns, the monocyte ex vivo response to LPS stimulus showed an over-production of cytokines within 6–12 hours, but low production in the late stage. Although unable to totally prevent the abnormality of the monocyte secretion function, CVVH showed a dose-dependent ameliorative effect on it.

Conclusions

Monocytes are over-reactive to stimulus in the early stage of SAP, accompanied by a high level of plasma cytokines, and hypo-reactive to stimulus in the late stage of SAP, accompanied with a low level of plasma cytokines. CVVH treatment has a dose-dependent improvement effect on monocyte responsiveness.

Measuring deaminated nucleotide surveillance enzyme ITPA activity with an ATP-releasing nucleotide chimera

Nucleotide quality surveillance enzymes play important roles in human health, by detecting damaged molecules in the nucleotide pool and deactivating them before they are incorporated into chromosomal DNA or adversely affect metabolism. In particular, deamination of adenine moiety in (deoxy)nucleoside triphosphates, resulting in formation of (d)ITP, can be deleterious, leading to DNA damage, mutagenesis and other harmful cellular effects. The 21.5 kDa human enzyme that mitigates this damage by conversion of (d)ITP to monophosphate, ITPA, has been proposed as a possible therapeutic and diagnostic target for multiple diseases. Measuring the activity of this enzyme is useful both in basic research and in clinical applications involving this pathway, but current methods are nonselective and are not applicable to measurement of the enzyme from cells or tissues. Here, we describe the design and synthesis of an ITPA-specific chimeric dinucleotide (DIAL) that replaces the pyrophosphate leaving group of the native substrate with adenosine triphosphate, enabling sensitive detection via luciferase luminescence signaling. The probe is shown to function sensitively and selectively to quantify enzyme activity in vitro, and can be used to measure the activity of ITPA in bacterial, yeast and human cell lysates.

Replication studies of carboxymethylated DNA lesions in human cells

Metabolic activation of some N-nitroso compounds (NOCs), an important class of DNA damaging agents, can induce the carboxymethylation of nucleobases in DNA. Very little was previously known about how the carboxymethylated DNA lesions perturb DNA replication in human cells. Here, we investigated the effects of five carboxymethylated DNA lesions, i.e. O⁶-CMdG, N⁶-CMdA, N⁴-CMdC, N3-CMdT and O⁴-CMdT on the efficiency and fidelity of DNA replication in HEK293T human embryonic kidney cells. We found that, while neither N⁶-CMdA nor N⁴-CMdC blocked DNA replication or induced mutations, N3-CMdT, O⁴-CMdT and O⁶-CMdG moderately blocked DNA replication and induced substantial frequencies of T→A (81%), T→C (68%) and G→A (6.4%) mutations, respectively. In addition, our results revealed that CRISPR-Cas9-mediated depletion of Pol η resulted in significant drops in bypass efficiencies of N⁴-CMdC and N3-CMdT. Diminution in bypass efficiencies was also observed for N⁶-CMdA and O⁶-CMdG upon depletion of Pol κ, and for O⁶-CMdG upon removal of Pol ζ. Together, our study provided molecular-level insights into the impacts of the carboxymethylated DNA lesions on DNA replication in human cells, revealed the roles of individual translesion synthesis DNA polymerases in bypassing these lesions, and suggested the contributions of O⁶-CMdG, N3-CMdT and O⁴-CMdT to the mutations found in p53 gene of human gastrointestinal cancers.

A Chimeric ATP-Linked Nucleotide Enables Luminescence Signaling of Damage Surveillance by MTH1, a Cancer Target

The enzyme MTH1 cleanses the cellular nucleotide pool of oxidatively damaged 8-oxo-dGTP, preventing mutagenesis by this nucleotide. The enzyme is considered a promising therapeutic target; however, methods to measure its activity are indirect and laborious and have low sensitivity. Here we describe a novel ATP-linked chimeric nucleotide (ARGO) that enables luminescence signaling of the enzymatic reaction, greatly simplifying the measurement of MTH1 activity. We show that the reporting system can be used to identify inhibitors of MTH1, and we use it to quantify enzyme activity in eight cell lines and in colorectal tumor tissue. The ARGO reporter is likely to have considerable utility in the study of the biology of MTH1 and potentially in analyzing patient samples during clinical testing.