Ontogeny of Human Liver Aldehyde Oxidase: Developmental Changes and Implications for Drug Metabolism.

Despite the increasing importance of aldehyde oxidase (AO) in the drug metabolism of clinical candidates, ontogeny data for AO are limited. The objective of our study was to characterize the age-dependent AO content and activity in the human liver cytosolic fraction (HLC) and human hepatocytes (HH). HLC (n = 121 donors) and HH (n = 50 donors) were analyzed for (1) AO protein content by quantitative proteomics and (2) enzyme activity using carbazeran as a probe substrate. AO activity showed high technical variability and poor correlation with the content in HLC samples, whereas hepatocyte samples showed a strong correlation between the content and activity. Similarly, AO content and activity showed no significant age-dependent differences in HLC samples, whereas the average AO content and activity in hepatocytes increased significantly (∼20-40-fold) from the neonatal levels (0-28 days). Based on the hepatocyte data, the age at which 50% of the adult AO content is reached (age50) was 3.15 years (0.32-13.97 years, 95% CI). Metabolite profiling of carbazeran revealed age-dependent metabolic switching and the role of non-AO mechanisms (glucuronidation and desmethylation) in carbazeran elimination. The content-activity correlation in hepatocytes improved significantly (R2 = 0.95; p < 0.0001) in samples showing <10% contribution of glucuronidation toward the overall metabolism, confirming that AO-mediated oxidation and glucuronidation are the key routes of carbazeran metabolism. Considering the confounding effect of glucuronidation on AO activity, AO content-based ontogeny data are a more direct reflection of developmental changes in protein expression. The comprehensive ontogeny data of AO in HH samples are more reliable than HLC data, which are important for developing robust physiologically based pharmacokinetic models for predicting AO-mediated metabolism in children.

Dissecting Parameters Contributing to the Underprediction of Aldehyde Oxidase-Mediated Metabolic Clearance of Drugs.

We investigated the effect of variability and instability in aldehyde oxidase (AO) content and activity on the scaling of in vitro metabolism data. AO content and activity in human liver cytosol (HLC) and five recombinant human AO preparations (rAO) were determined using targeted proteomics and carbazeran oxidation assay, respectively. AO content was highly variable as indicated by the relative expression factor (REF; i.e., HLC to rAO content) ranging from 0.001 to 1.7 across different in vitro systems. The activity of AO in HLC degrades at a 10-fold higher rate in the presence of the substrate as compared with the activity performed after preincubation without substrate. To scale the metabolic activity from rAO to HLC, a protein-normalized activity factor (pnAF) was proposed wherein the activity was corrected by AO content, which revealed up to sixfold higher AO activity in HLC versus rAO systems. A similar value of pnAF was observed for another substrate, ripasudil. Physiologically based pharmacokinetic (PBPK) modeling revealed a significant additional clearance (CL; 66%), which allowed for the successful prediction of in vivo CL of four other substrates, i.e., O-benzyl guanine, BIBX1382, zaleplon, and zoniporide. For carbazeran, the metabolite identification study showed that the direct glucuronidation may be contributing to around 12% elimination. Taken together, this study identified differential protein content, instability of in vitro activity, role of additional AO clearance, and unaccounted metabolic pathways as plausible reasons for the underprediction of AO-mediated drug metabolism. Consideration of these factors and integration of REF and pnAF in PBPK models will allow better prediction of AO metabolism. SIGNIFICANCE STATEMENT: This study elucidated the plausible reasons for the underprediction of aldehyde oxidase (AO)-mediated drug metabolism and provided recommendations to address them. It demonstrated that integrating protein content and activity differences and accounting for the loss of AO activity, as well as consideration of extrahepatic clearance and additional pathways, would improve the in vitro to in vivo extrapolation of AO-mediated drug metabolism using physiologically based pharmacokinetic modeling.

Analysis of the Bile Acid Composition in a Fibroblast Growth Factor 19-Expressing Liver-Humanized Mouse Model and Its Use for CYP3A4-Mediated Drug-Drug Interaction Studies.

Numerous biomedical applications have been described for liver-humanized mouse models, such as in drug metabolism or drug-drug interaction (DDI) studies. However, the strong enlargement of the bile acid (BA) pool due to lack of recognition of murine intestine-derived fibroblast growth factor-15 by human hepatocytes and a resulting upregulation in the rate-controlling enzyme for BA synthesis, cytochrome P450 (CYP) 7A1, may pose a challenge in interpreting the results obtained from such mice. To address this challenge, the human fibroblast growth factor-19 (FGF19) gene was inserted into the Fah-/- , Rag2-/- , Il2rg-/- NOD (FRGN) mouse model, allowing repopulation with human hepatocytes capable of responding to FGF19. While a decrease in CYP7A1 expression in human hepatocytes from humanized FRGN19 mice (huFRGN19) and a concomitant reduction in BA production was previously shown, a detailed analysis of the BA pool in these animals has not been elucidated. Furthermore, there are sparse data on the use of this model to assess potential clinical DDI. In the present work, the change in BA composition in huFRGN19 compared with huFRGN control animals was systematically evaluated, and the ability of the model to recapitulate a clinically described CYP3A4-mediated DDI was assessed. In addition to a massive reduction in the total amount of BA, FGF19 expression in huFRGN19 mice resulted in significant changes in the profile of various primary, secondary, and sulfated BAs in serum and feces. Moreover, as observed clinically, administration of the pregnane X receptor agonist rifampicin reduced the oral exposure of the CYP3A4 substrate triazolam. SIGNIFICANCE STATEMENT: Transgenic expression of FGF19 normalizes the unphysiologically high level of bile acids in a chimeric liver-humanized mouse model and leads to massive changes in bile acid composition. These adaptations could overcome one of the potential impediments in the use of these mouse models for drug-drug interaction studies.

Challenges and Opportunities for In Vitro-In Vivo Extrapolation of Aldehyde Oxidase-Mediated Clearance: Toward a Roadmap for Quantitative Translation.

Underestimation of aldehyde oxidase (AO)-mediated clearance by current in vitro assays leads to uncertainty in human dose projections, thereby reducing the likelihood of success in drug development. In the present study we first evaluated the current drug development practices for AO substrates. Next, the overall predictive performance of in vitro-in vivo extrapolation of unbound hepatic intrinsic clearance (CLint,u) and unbound hepatic intrinsic clearance by AO (CLint,u,AO) was assessed using a comprehensive literature database of in vitro (human cytosol/S9/hepatocytes) and in vivo (intravenous/oral) data collated for 22 AO substrates (total of 100 datapoints from multiple studies). Correction for unbound fraction in the incubation was done by experimental data or in silico predictions. The fraction metabolized by AO (fmAO) determined via in vitro/in vivo approaches was found to be highly variable. The geometric mean fold errors (gmfe) for scaled CLint,u (mL/min/kg) were 10.4 for human hepatocytes, 5.6 for human liver cytosols, and 5.0 for human liver S9, respectively. Application of these gmfe's as empirical scaling factors improved predictions (45%-57% within twofold of observed) compared with no correction (11%-27% within twofold), with the scaling factors qualified by leave-one-out cross-validation. A road map for quantitative translation was then proposed following a critical evaluation on the in vitro and clinical methodology to estimate in vivo fmAO In conclusion, the study provides the most robust system-specific empirical scaling factors to date as a pragmatic approach for the prediction of in vivo CLint,u,AO in the early stages of drug development. SIGNIFICANCE STATEMENT: Confidence remains low when predicting in vivo clearance of AO substrates using in vitro systems, leading to de-prioritization of AO substrates from the drug development pipeline to mitigate risk of unexpected and costly in vivo impact. The current study establishes a set of empirical scaling factors as a pragmatic tool to improve predictability of in vivo AO clearance. Developing clinical pharmacology strategies for AO substrates by utilizing mass balance/clinical drug-drug interaction data will help build confidence in fmAO.

Comparisons between human and rodent hepatic glutathione S-Transferase activities reveal sex and species differences.

Glutathione S-transferases (GSTs) are conjugating enzymes involved in drug metabolism, antioxidant defence, and cell signalling. Herein, we investigated hepatic GST conjugation in several mouse and rat strains, including both sexes, with a direct comparison to humans.Using general and isoform-selective substrates, all mouse strains had significantly greater activities than humans for total cytosolic GST, GST-M, GST-T, and microsomal GST activities. Some strains had significantly greater GST-P activities compared to humans. Sex differences between males and females were evident in all strains for total cytosolic GST, GST-M, and GST-P, and sex differences in GST-T and microsomal GST activities within strains were noted.All rats had significantly greater activities than humans for GST-M and GST-T; only some strains were significantly greater than humans for GST-P, total cytosolic GST, and microsomal GST. Sex differences within strains showed significantly greater GST-M and GST-T activities in males compared to females. Select strains showed sex differences for total cytosolic and microsomal GST activities; there were no sex differences in GST-P activities.Significant differences in glutathione conjugation between humans and rodents exist, including sex differences. This highlights the need for careful animal selection in pre-clinical studies where GSTs are the primary metabolic pathway.

Fluoride and gallein inhibit polyphosphate accumulation by oral pathogen Rothia dentocariosa.

The uptake and storage of extracellular orthophosphate (Pi) by polyphosphate (polyP) accumulating bacteria may contribute to mineral dissolution in the oral cavity. To test the effect of potential inhibitors of polyP kinases on Rothia dentocariosa, gallein (0, 25, 50, and 100 µM) and fluoride (0, 50, and 100 ppm) were added to R. dentocariosa cultures grown in brain-heart infusion broth. At a late log growth phase (8 h), extracellular Pi was measured using an ascorbic acid assay, and polyP was isolated from bacterial cells treated with RNA/DNAases using a neutral phenol/chloroform extraction. Extracts were hydrolyzed and quantified as above. Gallein and fluoride had minor effects on bacterial growth with NaF having a direct effect on media pH. Gallein (≥25 µM) and fluoride (≥50 ppm) attenuated the bacterial drawdown of extracellular Pi by 56.7% (P < 0.05) and 37.3% (P < 0.01). There was a corresponding polyP synthesis decrease of 73.2% (P < 0.0001) from gallein and 83.1% (P < 0.0001) from fluoride. Attenuated total reflectance-Fourier-transform infrared spectroscopy validated the presence of polyP and its reduced concentration in R. dentocariosa bacterial cells following gallein and fluoride treatment. Rothia dentocariosa can directly change extracellular Pi and accumulate intracellular polyP, but the mechanism is attenuated by gallein and NaF.

Monocarboxylate Transporters (SLC16): Function, Regulation, and Role in Health and Disease.

The solute carrier family 16 (SLC16) is comprised of 14 members of the monocarboxylate transporter (MCT) family that play an essential role in the transport of important cell nutrients and for cellular metabolism and pH regulation. MCTs 1-4 have been extensively studied and are involved in the proton-dependent transport of L-lactate, pyruvate, short-chain fatty acids, and monocarboxylate drugs in a wide variety of tissues. MCTs 1 and 4 are overexpressed in a number of cancers, and current investigations have focused on transporter inhibition as a novel therapeutic strategy in cancers. MCT1 has also been used in strategies aimed at enhancing drug absorption due to its high expression in the intestine. Other MCT isoforms are less well characterized, but ongoing studies indicate that MCT6 transports xenobiotics such as bumetanide, nateglinide, and probenecid, whereas MCT7 has been characterized as a transporter of ketone bodies. MCT8 and MCT10 transport thyroid hormones, and recently, MCT9 has been characterized as a carnitine efflux transporter and MCT12 as a creatine transporter. Expressed at the blood brain barrier, MCT8 mutations have been associated with an X-linked intellectual disability, known as Allan-Herndon-Dudley syndrome. Many MCT isoforms are associated with hormone, lipid, and glucose homeostasis, and recent research has focused on their potential roles in disease, with MCTs representing promising novel therapeutic targets. This review will provide a summary of the current literature focusing on the characterization, function, and regulation of the MCT family isoforms and on their roles in drug disposition and in health and disease. SIGNIFICANCE STATEMENT: The 14-member solute carrier family 16 of monocarboxylate transporters (MCTs) plays a fundamental role in maintaining intracellular concentrations of a broad range of important endogenous molecules in health and disease. MCTs 1, 2, and 4 (L-lactate transporters) are overexpressed in cancers and represent a novel therapeutic target in cancer. Recent studies have highlighted the importance of MCTs in glucose, lipid, and hormone homeostasis, including MCT8 in thyroid hormone brain uptake, MCT12 in carnitine transport, and MCT11 in type 2 diabetes.

Application of empirical scalars to enable early prediction of human hepatic clearance using IVIVE in drug discovery: an evaluation of 173 drugs.

The utilization of in vitro data to predict drug pharmacokinetics (PK) in vivo has been a consistent practice in early drug discovery for decades. However, its success is hampered by mispredictions attributed to uncharacterized biological phenomena/experimental artifacts. Predicted drug clearance (CL) from experimental data (i.e. hepatocyte intrinsic clearance: CLint, fraction unbound in plasma: fu,p) is often systematically underpredicted using the well-stirred model (WSM). The objective of this study was to evaluate using empirical scalars in the WSM to correct for CL mispredictions. Drugs (N=28) were used to generate numerical scalars on CLint (α), and fu,p (ß) to minimize the error (AAFE) for CL predictions. These scalars were validated using an additional dataset (N=28 drugs) and applied to a non-redundant AstraZeneca (AZ) dataset available in the literature (N=117 drugs) for a total of 173 compounds. CL predictions using the WSM were improved for most compounds using an α value of 3.66 (~64%<2-fold) compared to no scaling (~46%<2-fold). Similarly, using a ß value of 0.55 or combination of α and ß scalars (values of 1.74 and 0.66, respectively) resulted in a similar improvement in predictions (~64%<2-fold and ~65%<2-fold, respectively). For highly bound compounds (fu,p{less than or equal to}0.01), AAFE was substantially reduced across all scaling methods. Using the ß scalar alone or a combination of α and ß appeared optimal; and produce larger magnitude corrections for highly-bound compounds. Some drugs are still disproportionally mispredicted, however the improvements in prediction error and simplicity of applying these scalars suggests its utility for early-stage CL predictions. Significance Statement In early drug discovery, prediction of human clearance using in vitro experimental data plays an essential role in triaging compounds prior to in vivo studies. These predictions have been systematically underestimated. Here we introduce empirical scalars calibrated on the extent of plasma protein binding that appear to improve clearance prediction across multiple datasets. This approach can be used in early phases of drug discovery prior to the availability of pre-clinical data for early quantitative predictions of human clearance.

The experiences of therapists providing psychological treatment for adults with depression and intellectual disabilities as part of a randomised controlled trial.

BACKGROUND: Health professionals were trained to deliver adapted psychological interventions for depression to people with learning disabilities and depression alongside a supporter. Exploring the delivery of psychological interventions can help increase access to therapy. METHOD: Twenty-seven participants took part in six focus groups, and the data were subject to a Framework Analysis. RESULTS: The structure and focus of the manualised therapies, and the use of specific techniques were perceived as key to service-user engagement. Supporters' involvement was valued by therapists if they had a good relationship and regular contact with the individual they supported. Regular clinical supervision was regarded as vital in understanding their role, assessing progress and delivering the interventions. CONCLUSIONS: The findings highlight that health professionals can embrace a focussed therapeutic role and increase access to psychological therapies for people with intellectual disabilities.

Detection of SARS-CoV-2 IgG Targeting Nucleocapsid or Spike Protein by Four High-Throughput Immunoassays Authorized for Emergency Use.

A total of 1,200 serum samples that were tested for SARS-CoV-2 IgG antibody using the Abbott Architect immunoassay targeting the nucleocapsid protein were run in 3 SARS-CoV-2 IgG immunoassays targeting spike proteins (DiaSorin Liaison, Ortho Vitros, and Euroimmun). Consensus-positive and consensus-negative interpretations were defined as qualitative agreement in at least 3 of the 4 assays. Agreement of the 4 individual assays with a consensus-negative interpretation (n = 610) ranged from 96.7% to 100%, and agreement with a consensus-positive interpretation (n = 584) ranged from 94.3% to 100%. Laboratory-developed inhibition assays were utilized to evaluate 49 consensus-negative samples that were positive in only one assay; true-positive reactivity was confirmed in only 2 of these 49 (4%) samples. These findings demonstrate very high levels of agreement among 4 SARS-CoV-2 IgG assays authorized for emergency use, regardless of antigen target or assay format. Although false-positive reactivity was identified, its occurrence was rare (no more than 1.7% of samples for a given assay).

Contribution of Monocarboxylate Transporter 6 to the Pharmacokinetics and Pharmacodynamics of Bumetanide in Mice.

Bumetanide, a sulfamyl loop diuretic, is used for the treatment of edema in association with congestive heart failure. Being a polar, anionic compound at physiologic pH, bumetanide uptake and efflux into different tissues is largely transporter-mediated. Of note, organic anion transporters (SLC22A) have been extensively studied in terms of their importance in transporting bumetanide to its primary site of action in the kidney. The contribution of one of the less-studied bumetanide transporters, monocarboxylate transporter 6 (MCT6; SLC16A5), to bumetanide pharmacokinetics (PK) and pharmacodynamics (PD) has yet to be characterized. The affinity of bumetanide for murine Mct6 was evaluated using Mct6-transfected Xenopus laevis oocytes. Furthermore, bumetanide was intravenously and orally administered to wild-type mice (Mct6+/+) and homozygous Mct6 knockout mice (Mct6-/-) to elucidate the contribution of Mct6 to bumetanide PK/PD in vivo. We demonstrated that murine Mct6 transports bumetanide at a similar affinity compared with human MCT6 (78 and 84 µM, respectively, at pH 7.4). After bumetanide administration, there were no significant differences in plasma PK. Additionally, diuresis was significantly decreased by ∼55% after intravenous bumetanide administration in Mct6-/- mice. Kidney cortex concentrations of bumetanide were decreased, suggesting decreased Mct6-mediated bumetanide transport to its site of action in the kidney. Overall, these results suggest that Mct6 does not play a major role in the plasma PK of bumetanide in mice; however, it significantly contributes to bumetanide's pharmacodynamics due to changes in kidney concentrations. SIGNIFICANCE STATEMENT: Previous evidence suggested that MCT6 transports bumetanide in vitro; however, no studies to date have evaluated the in vivo contribution of this transporter. In vitro studies indicated that mouse and human MCT6 transport bumetanide with similar affinities. Using Mct6 knockout mice, we demonstrated that murine Mct6 does not play a major role in the plasma pharmacokinetics of bumetanide; however, the pharmacodynamic effect of diuresis was attenuated in the knockout mice, likely because of the decreased bumetanide concentrations in the kidney.

Characterization and Proteomic-Transcriptomic Investigation of Monocarboxylate Transporter 6 Knockout Mice: Evidence of a Potential Role in Glucose and Lipid Metabolism.

Monocarboxylate transporter 6 [(MCT6), SLC16A5] is an orphan transporter with no known endogenous substrates or physiological role. Previous in vitro and in vivo experiments investigated MCT6 substrate/inhibitor specificity in Xenopus laevis oocytes; however, these data remain limited. Transcriptomic changes in the livers of mice undergoing different dieting schemes have suggested that Mct6 plays a role in glucose and lipid metabolism. The objectives of this study were 1) to develop a novel knockout (KO) mouse model (Mct6-/-) using CRISPR/Cas9 technology, 2) to characterize the KO animal model by examining physiological and biochemical parameters, and 3) to understand the physiological role of MCT6 in vivo through global proteomic and liver transcriptomic profiling. mRNA tissue analysis demonstrated knockout of Mct6, which showed greater than 90% knockdown of Mct6 (Slc16a5) gene expression in all major tissues analyzed when normalized to Mct6+/+ mice. Proteomic analyses identified greater than 4000 unique proteins in kidney, liver, and colon tissues, among which 51, 38, and 241 proteins were significantly altered, respectively (for each tissue), between Mct6+/+ and Mct6-/- mice. Additionally, Mct6-/- mice demonstrated significant changes in 199 genes in the liver compared with Mct6+/+ mice. In silico biological pathway analyses revealed significant changes in proteins and genes involved in glucose and lipid metabolism-associated pathways. This study is the first to provide evidence for an association of Mct6 in the regulation of glucose and lipid metabolism. SIGNIFICANCE STATEMENT: This paper focuses on elucidating the innate biological role of an orphan transporter in vivo, which has not been investigated thus far. Using efficient and high-throughput technologies, such as CRISPR/Cas9 gene editing, liquid chromatography-tandem mass spectrometry-based proteomic and RNA-sequencing transcriptomic analyses, our laboratory provides the first existence and characterization of a Mct6 knockout mouse model. The evidence gathered in this paper, as well as other laboratories, support the importance of MCT6 in regulating a variety of glucose and lipid metabolic pathways, which may indicate its significance in metabolic diseases.

Investigating the Impact of Albumin on the Liver Uptake of Pitavastatin and Warfarin in Nagase Analbuminemic Rats.

Albumin has been suggested to enhance the hepatic uptake of organic anion-transporting polypeptide (Oatp) substrates in various in vitro as well as liver perfusion models. However, it is not known whether the interplay between albumin and Oatp substrates is an experimental artifact or if this interaction occurs in vivo. The objective of this work was to investigate the hepatic uptake of warfarin and pitavastatin, which are both extensively bound to albumin but only pitavastatin being an Oatp substrate. Experiments were conducted in Nagase analbuminemic rats (NAR) which exhibit reduced albumin levels compared with F344 (wild type, WT). The fraction unbound (f u) was 140- and 10-fold greater in NAR plasma for warfarin and pitavastatin, respectively, whereas no meaningful differences were observed with tissue binding. In vitro, pitavastatin uptake into hepatocytes reconstituted in WT plasma was 17- and 3-fold greater than when reconstituted in buffer or NAR plasma, respectively. In vivo, the free tissue-to-free plasma ratios (K p,u,u) from brain and liver in intact WT and NAR were not significantly different for warfarin. Contrarily, liver K p,u,u of pitavastatin was 6-fold higher in WT animals, which corresponded to a 2.3-fold reduction in free plasma and 2.6-fold increase in free liver exposure. These results suggest that the enhanced hepatic uptake by albumin is not necessarily an experimental artifact but is also a relevant phenomenon in vivo. This work raises the possibility that other plasma proteins may also effect the function of additional drug transporters, and that modulating plasma protein binding may exhibit meaningful clinical relevance in the disposition of drugs. SIGNIFICANCE STATEMENT: The interplay between albumin and Oatp substrates has been reported in hepatocytes and in liver perfusion studies, but the in vivo relevance of this interaction has yet to be elucidated. Using NAR and its corresponding WT animal, this study demonstrates that albumin may indeed enhance the hepatic uptake of pitavastatin in intact animals. In vivo demonstration of this interplay not only provides further justification for continued investigation into this particular mechanism but also raises the possibility that other plasma proteins may affect additional drug transporters and that modulating plasma protein binding may exhibit meaningful clinical relevance in the disposition of drugs.

Polyphosphate-Accumulating Bacteria: Potential Contributors to Mineral Dissolution in the Oral Cavity.

Bacteria that accumulate polyphosphates have previously been shown to dynamically influence the solubility of phosphatic minerals in marine settings and wastewater. Here, we show that dental plaque, saliva, and carious lesions all contain abundant polyphosphate-accumulating bacteria. Saturation state modeling results, informed by phosphate uptake experiments using the model organism Lactobacillus rhamnosus, which is known to inhabit advanced carious lesions, suggest that polyphosphate accumulation can lead to undersaturated conditions with respect to hydroxyapatite under some oral cavity conditions. The cell densities of polyphosphate-accumulating bacteria we observed in some regions of oral biofilms are comparable to those that produce undersaturated conditions (i.e., those that thermodynamically favor mineral dissolution) in our phosphate uptake experiments with L. rhamnosus These results suggest that the localized generation of undersaturated conditions by polyphosphate-accumulating bacteria constitutes a new potential mechanism of tooth dissolution that may augment the effects of metabolic acid production.IMPORTANCE Dental caries is a serious public health issue that can have negative impacts on overall quality of life and oral health. The role of oral bacteria in the dissolution of dental enamel and dentin that can result in carious lesions has long been solely ascribed to metabolic acid production. Here, we show that certain oral bacteria may act as a dynamic shunt for phosphate in dental biofilms via the accumulation of a polymer known as polyphosphate-potentially mediating phosphate-dependent conditions such as caries (dental decay).

The benefits of errorless learning for people with amnestic mild cognitive impairment.

The aim of this study was to explore whether errorless learning leads to better outcomes than errorful learning in people with amnestic mild cognitive impairment (MCI), and to examine whether accuracy in error recognition relates to any observed benefit of errorless over errorful learning. Nineteen participants with a clinical diagnosis of amnestic MCI were recruited. A word-list learning task was used and learning was assessed by free recall, cued recall and recognition tasks. Errorless learning was significantly superior to errorful learning for both free recall and cued recall. The benefits of errorless learning were less marked in participants with better error recognition ability. Errorless learning methods are likely to prove more effective than errorful methods for those people with MCI whose ability to monitor and detect their own errors is impaired.

The role of shame in the development and maintenance of psychological distress in adults with intellectual disabilities: A narrative review and synthesis.

BACKGROUND: The role of shame in the development and maintenance of psychological distress in adults with mild-to-moderate intellectual disabilities has been relatively under-researched. This study provides a review of diverse current research that has implicitly or explicitly investigated shame processes in this population in some form. METHODS: A narrative review of the literature was undertaken. An electronic search of four databases identified 17 studies that met the eligibility criteria. RESULTS: Findings indicate that individuals with mild-to-moderate intellectual disabilities may experience difficulties with both external and internal shame, which appear to be related to increased psychological distress. Experiences of being shamed may significantly negatively impact on self-to-self and other self-relating, processes of social comparison, subsequent self-worth and emotional well-being. CONCLUSION: Shame may be a contributory factor in the development and maintenance of psychological distress and subsequent mental health issues in some adults with mild-to-moderate intellectual disabilities.

Quercetin, Morin, Luteolin, and Phloretin Are Dietary Flavonoid Inhibitors of Monocarboxylate Transporter 6.

Monocarboxylate transporter 6 (MCT6; SLC16A5) has been recognized for its role as a xenobiotic transporter, with characterized substrates probenecid, bumetanide, and nateglinide. To date, the impact of commonly ingested dietary compounds on MCT6 function has not been investigated, and therefore, the objective of this study was to evaluate a variety of flavonoids for their potential MCT6-specific interactions. Flavonoids are a large group of polyphenolic phytochemicals found in commonly consumed plant-based products that have been recognized for their dietary health benefits. The uptake of bumetanide in human MCT6 gene-transfected Xenopus laevis oocytes was significantly decreased in the presence of a variety of flavonoids (e.g., quercetin, luteolin, phloretin, and morin), but was not significantly affected by flavonoid glycosides (e.g., naringin, rutin, phlorizin). The IC50 values of quercetin, phloretin, and morin were determined to be 25.3 ± 3.36, 17.3 ± 2.37, and 33.1 ± 3.29 µM, respectively. The mechanism of inhibition of phloretin was reversible and competitive, with a Ki value of 22.8 µM. Furthermore, typical MCT substrates were also investigated for their potential interactions with MCT6. Substrates of MCTs 1, 2, 4, 8, and 10 did not cause any significant decrease in MCT6-mediated bumetanide uptake, suggesting that MCT6 has distinct compound selectivity. In summary, these results suggest that dietary aglycon flavonoids may significantly alter the pharmacokinetics and pharmacodynamics of bumetanide and other MCT6-specific substrates, and may represent potential substrates for MCT6.

Real-time imaging of anti-biofilm effects using CP-OCT.

The objective of this study was to develop a method to reliably and reproducibly assess the physical properties of in vitro multi-species plaque derived biofilms. A custom flow cell (FC) was designed to model oral cavity shear stresses on biofilms grown on hydroxyapatite (HA) discs. A finite-element program (ANSYS 13) modeled flow velocities and wall shear stresses on the interior 3D dimensions. For the experiment, 1% chlorhexidine (CHX), 5 M urea, and a 1× phosphate-buffered saline (PBS) were flown through the FC simulating oral rinsing. Near infrared cross-polarization optical coherence tomography (CP-OCT) non-destructively imaged the fluid immersed biofilms in real time (20 frames/s). During low flow, the swell of the biofilm caused from 5 M urea was quite pronounced increase in vertical dimension. Biofilms exposed to 1% CHX showed a slight collapse in the vertical dimension of the biofilm during low flow. During high flow/high sheer stress, the 5 M urea solution effectively removed the biofilm, while both 1% CHX and 1× PBS did not remove biofilms even under high velocity/shear stress conditions.

Comparing potential early caries assessment methods for teledentistry.

BACKGROUND: Optical caries detection has the potential to be incorporated in telehealth medicine for preventive dental screening. The objective of this study was to evaluate and compare visible and near infrared detection methods for identifying early non-cavitated ex vivo occlusal demineralization. METHODS: Six blinded examiners were used to compare the accuracy of the following three examinations in detecting occlusal demineralization: Midwest Caries ID (MID), visual photographic examination (CAM) and Cross Polarization Optical Coherence Tomography (CP-OCT). For each diagnostic method, two examiners assessed the extracted tooth samples 1-2 weeks apart. Teeth were then sectioned and lesion depth was confirmed (n = 42) by a blinded histological examination using a glycol based caries indicator dye. The sensitivity (Sen), specificity (Sp), Intraclass Correlation Coefficient (ICC), and Area under the Receiver Operator Curve (AUC) were calculated. RESULTS: For detecting any demineralization versus sound pit and fissure enamel, the mean Sen/Sp found was 46.9/85.0 for MID, 80.5/52.5 for CAM, and 83.4/45.0 for CP-OCT. For detecting non-cavitated demineralization that progressed into the dentin, the mean Sen/Sp found was 17.3/88.0 for MID, 48.0/57.8 for CAM, and 44.2/72.7 for CP-OCT. AUC values were statistically significant (P < 0.05) in three out of four examiner assessments when MID and CP-OCT were used to detect any demineralization. AUC values were significant for a single CAM examination. When assessing deeper non-cavitated lesions, none of the assessment methods were able to yield AUC values that were significantly different than a random 'coin flip' test. When examining reliability, MID demonstrated the highest ICC score (0.83) and CP-OCT had the lowest (0.49). CONCLUSION: Although MID and CP-OCT were useful in detecting the presence of demineralization, examiners were not able to utilize these devices to adequately assess the depth of the demineralization. This study found that MID and CP-OCT did not have markedly superior diagnostic values from simple CAM assessment for use in teledentistry.