Search

Background: Prone positioning may improve oxygenation in acute hypoxemic respiratory failure and was widely adopted in COVID‐19 patients. However, the magnitude and timing of its peak oxygenation effect remain uncertain with the optimum dosage unknown. Therefore, we aimed to investigate the magnitude of the peak effect of prone positioning on the PaO2:FiO2 ratio during prone and secondly, the time to peak oxygenation. Methods: Multi‐centre, observational study of invasively ventilated adults with acute hypoxemic respiratory failure secondary to COVID‐19 treated with prone positioning. Baseline characteristics, prone positioning and patient outcome data were collected. All arterial blood gas (ABG) data during supine, prone and after return to supine position were analysed. The magnitude of peak PaO2:FiO2 ratio effect and time to peak PaO2:FIO2 ratio effect was measured. Results: We studied 220 patients (mean age 54 years) and 548 prone episodes. Prone positioning was applied for a mean (±SD) 3 (±2) times and 16 (±3) hours per episode. Pre‐proning PaO2:FIO2 ratio was 137 (±49) for all prone episodes. During the first episode. the mean PaO2:FIO2 ratio increased from 125 to a peak of 196 (p <.001). Peak effect was achieved during the first episode, after 9 (±5) hours in prone position and maintained until return to supine position. Conclusions: In ventilated adults with COVID‐19 acute hypoxemic respiratory failure, peak PaO2:FIO2 ratio effect occurred during the first prone positioning episode and after 9 h. Subsequent episodes also improved oxygenation but with diminished effect on PaO2:FIO2 ratio. This information can help guide the number and duration of prone positioning episodes. [ABSTRACT FROM AUTHOR]

Aims: The Austraian Treatment Outcomes Profile (ATOP) is a brief clinical outcomes tool used widely in the Australian alcohol and other drugs treatment sector to monitor clients' substance use, health, wellbeing and clinical risk factors. It has demonstrated reliability and validity, and has recommended clinical cut‐offs for assessing single‐occasion client‐rated health scores. This study determined clinically meaningful change thresholds for ATOP substance use and health and wellbeing variables for use by clinicians in monitoring client progress, and for quality improvement and service evaluation. Design, Setting and Participants: A framework for assessing clinically meaningful changes scores was developed by (1) calculating statistically reliable change thresholds using data‐driven techniques with a reference sample of clinical ATOP data and (2) conducting a multi‐disciplinary subject matter expert group to review the utility and validity of data‐derived clinically meaningful change. The study was conducted within Outpatient Alcohol and Other Drug treatment services in New South Wales, Australia. The reference sample comprised 6100 ATOPs from clients at entry to public outpatient Alcohol and Other Drug treatment services; the subject matter expert group comprised 29 key stakeholders from the specialist alcohol and other drug treatment sector. Measurements and Findings: We used the Reliable Change Index method to calculate clinically meaningful change thresholds for ATOP variables. For substance use variables, a change of 30% in days of use in the last 28 (minimum 4 days) was the threshold for clinically meaningful change for substance use; for health and wellbeing variables, a change of 2 or more points in psychological health, physical health or quality of life scores (measured on 0–10 scales) was the minimum clinically meaningful change. Conclusions: Clinically meaningful change thresholds have been proposed for Australian Treatment Outcomes Profile substance use and health and wellbeing items, based on statistical reliability and subject matter expert assessment. These will be used in the development of an outcomes metric for assessing change and assigning meaning in aggregated data for evaluation of services. [ABSTRACT FROM AUTHOR]

Objective: To investigate the demographic characteristics, substance use, and self‐rated health of people entering treatment in New South Wales public health services for alcohol, amphetamine‐type stimulants, cannabis, cocaine, or opioids use, by principal drug of concern. Design: Baseline findings of a cohort study; analysis of data in patient electronic medical records and NSW minimum data set for drug and alcohol treatment services. Setting, participants: People completing initial Australian Treatment Outcomes Profile (ATOP) assessments on entry to publicly funded alcohol and other drug treatment services in six NSW local health districts/networks, 1 July 2016 – 30 June 2019. Main outcome measures: Socio‐demographic characteristics, and substance use and self‐rated health (psychological, physical, quality of life) during preceding 28 days, by principal drug of concern. Results: Of 14 087 people included in our analysis, the principal drug of concern was alcohol for 6051 people (43%), opioids for 3158 (22%), amphetamine‐type stimulants for 2534 (18%), cannabis for 2098 (15%), and cocaine for 246 (2%). Most people commencing treatment were male (9373, 66.5%), aged 20–39 years (7846, 50.4%), and were born in Australia (10 934, 86.7%). Polysubstance use was frequently reported, particularly by people for whom opioids or amphetamine‐type stimulants were the principal drugs of concern. Large proportions used tobacco daily (53–82%, by principal drug of concern group) and reported poor psychological health (47–59%), poor physical health (32–44%), or poor quality of life (43–52%). Conclusions: The prevalence of social disadvantage and poor health is high among people seeking assistance with alcohol, amphetamine‐type stimulants, cannabis, cocaine, or opioids use problems. Given the differences in these characteristics by principal drug of concern, health services should collect comprehensive patient information during assessment to facilitate more holistic, tailored, and person‐centred care. [ABSTRACT FROM AUTHOR]

Introduction: Standardised data collection processes allow for harmonisation and comparison of data across different studies and services. This project aimed to develop a 'core dataset' to serve as the default collection when designing future studies and evaluations, building upon data routinely collected in clinical alcohol and other drugs (AOD) settings in NSW, Australia. Methods: A working group was established, comprising clinicians, researchers, data managers and consumers from public sector and non‐government organisation AOD services in the NSW Drug and Alcohol Clinical Research and Improvement Network. A series of Delphi meetings occurred to reach consensus on the data items to be included in the core dataset for three domains: demographics, treatment activity and substance use variables. Results: There were 20–40 attendees at each meeting. An initial consensus criterion of having received >70% of the vote was established. Given the difficulty in reaching consensus for most items, subsequently, this was changed to eliminate items that received <5 votes, after which the item receiving the most votes would be selected. Discussions and Conclusions: This important process received considerable interest and buy‐in across the NSW AOD sector. Ample opportunity for discussion and voting was provided for the three domains of interest, allowing participants to contribute their expertise and experience to inform decisions. As such, we believe the core dataset includes the best options currently available to collect data for these domains in the NSW AOD context, and potentially more broadly. This foundational study may inform other attempts to harmonise data across AOD services. [ABSTRACT FROM AUTHOR]

Early childhood naps support emotional memory, but benefits are only observed after overnight sleep. Whether emotional memory consolidation occurs during naps, or whether napping only prepares memories for overnight consolidation is unknown. We investigated whether naps protect emotional memories from interference, indicating consolidation. Between 2018 and 2020, 63 children in western Massachusetts preschools (30 female, 33 male; 33–67 months; 23.8% Hispanic, 87.3% White) learned faces paired with negative or neutral descriptions, followed by nap or wake. Before delayed recognition, half completed an interference task. Without interference, napping benefited recognition. With interference, children recognized fewer negative faces post‐nap (compared to wake), with overnight sleep attenuating this difference. Results suggest that naps initially destabilize emotional memories, possibly reflecting partial processing that promotes long‐term consolidation. [ABSTRACT FROM AUTHOR]

Introduction: Amphetamine type substances (ATS) are commonly used by Australian alcohol and other drug service entrants. We describe demographic characteristics, patterns of ATS and other substance use, health and social conditions among clients entering New South Wales (NSW) public alcohol and other drug services. Methods: Retrospective cohort of 13,864 records across six health districts (2016–2019) for clients seeking substance use treatment. These districts service approximately 44% of the NSW population aged 15 years and over. Multivariate analysis was conducted on a subsample for whom full data were available (N = 9981). Data included NSW Minimum Data Set for drug and alcohol treatment services and Australian Treatment Outcomes Profile items. Results: Over the preceding 4 weeks, 77% (n = 10,610) of clients (N = 13,864) reported no recent ATS use, 15% (n = 2109) reported 'low frequency' (1–12 days) and 8% (n = 1145) 'high frequency' (13–28 days) use. ATS use was most common among people attending for ATS or opioids as primary drug of concern. A multinomial regression (N = 9981) identified that clients reporting recent arrest (aOR 1.74, 95% CI 1.36, 2.24), higher cannabis use frequency (aOR 1.01, 95% CI 1.00, 1.02), lower opioid use frequency (aOR 0.98, 95% CI 0.97, 0.99) and poorer quality of life (aOR 0.91, 95% CI 0.86, 0.97) were more likely to report 'high frequency' rather than 'low frequency' ATS use. Discussion and Conclusions: People who use ATS experience health and social issues that may require targeted responses. These should be integrated across all services, not only for clients with ATS as principal drug of concern. [ABSTRACT FROM AUTHOR]

Copyright of Risk, Hazards & Crisis in Public Policy is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: The Australian Treatment Outcomes Profile (ATOP) is a brief instrument that measures self‐reported substance use, health, and wellbeing in the previous 28 days for people in alcohol and other drug treatment. Previous studies have established the concurrent validity, inter‐rater, and test–retest reliability of the tool. The current study sought to identify recommended cutoff scores for ATOP items for psychological health, physical health and quality of life that identify clients reporting clinically significant problems warranting further assessment and/or intervention, compared to cutoffs used by 'gold‐standard' measures for these domains. Methods: Clients attending for treatment for problems with opioid (n = 144) or alcohol use (n = 134) completed the ATOP and comparison standardised questionnaires (Kessler‐10, Short Form Survey 12 and the Personal Wellbeing Index) with a researcher. Receiver operating characteristics analysis, along with clinician perspectives, were used to recommend cutoff scores for ATOP items indicative of clinically significant problems. Results: A cutoff score of 5 or less out of 10 was identified as an optimal pragmatic cutoff for ATOP items relating to psychological health, physical health and quality of life items with regards to balancing sensitivity, specificity, and application in a treatment setting. Discussion and Conclusions: The recommended clinical cutoffs will support clinicians and treatment services to identify clients who require further assessment and follow up for their psychological health, physical health and quality of life. The current study provides further evidence for the utility of the ATOP for individual clinical review, service planning and research. [ABSTRACT FROM AUTHOR]

Canine spontaneous cancers may offer greater fidelity than rodent models in advancing clinical immunotherapies. Boxers in particular are distinguished as study subjects by their popularity, and high incidence of human‐relevant cancers. Further, the MHC class I allele DLA‐88*034:01, with a known motif, dominates the breed, facilitating discovery of shared CTL responses against mutation‐origin neoepitopes by standard prediction methods. We experimentally confirmed the allomorph's binding motif by developing an MHC surface stabilization assay. The assay validated four DLA‐88*034:01‐presented peptides from canine distemper virus, ubiquitously administered in routine vaccines, for positive controls in future CTL studies. In turn, these viral peptides substantiated motif‐based prediction for DLA‐88*034:01. The study adds new tools for studying neoepitope‐specific CTL in Boxers to foster canine comparative oncology. [ABSTRACT FROM AUTHOR]

Background and Aims: The Australian Treatment Outcomes Profile (ATOP) is a brief instrument measuring recent substance use, risk profile and general health and wellbeing among clients attending alcohol and other drug (AoD) treatment services. This study evaluates the ATOP for concurrent validity, inter‐rater and test–re‐test reliability among alcohol and opioid treatment groups. Design For concurrent validity and inter‐rater reliability, participants completed an ATOP with a clinician and an ATOP plus standardized questionnaires (time‐line follow‐back, Opiate Treatment Index, Kessler‐10, 12‐item Short Form Survey, World Health Organization Quality of Life‐BREF, Personal Wellbeing Index) with a researcher within 3 days. For test–re‐test reliability, participants completed two ATOPs with a researcher within a 3‐day interval. Setting Outpatient AoD treatment centres in Australia. Participants: For testing concurrent validity and inter‐rater reliability, 278 participants were recruited by advertisements in waiting‐rooms or clinician invitation during 2016 to 2018. A further 94 participants were recruited to examine test–re‐test reliability. Measurements Statistical tests used for concurrent validity and test–re‐test reliability were Pearson's and Spearman's rank order correlations for continuous variables, and Cohen's κ for nominal variables. Inter‐rater reliability was assessed using Krippendorf's α. Findings Most Australian Treatment Outcomes Profile items returned excellent or moderate validity and reliability. For the main substances used—alcohol, cannabis and benzodiazepines—concurrent validity, inter‐rater reliability and test–re‐test reliability all reached excellent or good agreement (0.72–0.96). Psychological health, physical health and quality of life showed fair to strong agreement with their comparator scales (0.47–0.85). Conclusions: The Australian Treatment Outcomes Profile is a validated and reliable instrument for assessing recent substance use and clinical risk, health and welfare among alcohol and opioid clients in alcohol and other drug treatment settings. Its ability to reliably measure complex constructs, such as psychological and physical health, against longer scales makes it suitable for integration into routine clinical care, enabling regular monitoring of patient outcomes and safety parameters. [ABSTRACT FROM AUTHOR]

Introduction and Aims: The Australian Treatment Outcomes Profile (ATOP) is a brief clinical tool measuring recent substance use, health and wellbeing among clients attending alcohol and other drug (AOD) treatment services. It has previously been assessed for concurrent validity and inter-rater reliability. In this study we examine whether it is suitable for administration over the telephone.Design and Methods: We recruited a sample of 107 AOD clients across public sector specialist AOD treatment services in New South Wales, Australia between 2016 and 2018. Participants had a mean age of 47 years and 46% were female. Participants completed a face-to-face ATOP and a phone ATOP with a researcher within 5 days. Comparisons between the two administration modes were undertaken using Spearman's rank correlation coefficient for continuous or ordinal variables, and Cohen's Kappa for nominal variables.Results: Among 107 participants, 59% were attending for alcohol treatment and 41% for opioid treatment. Most ATOP items (76%) reached above 0.7 (good) or 0.9 (excellent) agreement between face-to-face and telephone use.Discussion and Conclusions: Our findings suggest that the ATOP is a suitable instrument for telephone monitoring of recent substance use, health and social functioning among AOD clients. Its validation for remote use over the telephone will support staff to monitor clients' risks and outcomes-of particular relevance in response to the COVID-19 pandemic in which services are increasingly relying on telework approaches to client monitoring. [ABSTRACT FROM AUTHOR]

This research note uses exploratory spatial data analysis (ESDA) to understand regional conflict escalation. This study suggests rethinking the use of strict thresholds of conflict in studies of civil war, given that hot spots are predictors of conflict escalation. In the Colombian case, human rights violations hot spots are predictors of higher intensity conflict escalation. [ABSTRACT FROM AUTHOR]

Cancer‐testis antigens (CTAs) are a category of self proteins aberrantly expressed in diverse malignancies, mostly solid tumours, due to epigenetic de‐repression. Normally expressed only in fetal or gametogenic tissues, CTAs are tantalizing immunotherapy targets, since autoimmunity risks appear minimal. Few prevalent CTAs have been identified in human hematologic cancers, and just two in their veterinary counterparts. We sought to discover new CTAs in canine hematologic cancers such as histiocytic sarcoma (HS) and lymphoma to foster immunotherapy development. To accomplish this, the ligandome binding the dog leukocyte antigen (DLA)‐88*508:01 class I allele overexpressed in an HS line was searched by mass spectrometry to identify possible CTA‐derived peptides, which could serve as CD8+ T‐cell epitopes. Twenty‐two peptides mapped to 5 human CTAs and 12 additional proteins with CTA characteristics. Expression of five promising candidates was then evaluated in tumour and normal tissue by quantitative and end‐point RT‐PCR. The ortholog of an established CTA, IGF2BP3, had unexpectedly high expression in peripheral blood mononuclear cells (PBMCs). Four other testis‐enhanced proteins were also assessed. AKR1E2, SPECC1 and TPX2 were expressed variably in HS and T‐cell lymphoma biopsies, but also at high levels in critical tissues, including kidney, brain and marrow, diminishing their utility. A more tissue‐restricted candidate, NT5C1B, was detected in T‐cell lymphomas, but also at low levels in some normal dog tissues. These results illustrate the feasibility of discovering canine CTAs by a reverse approach, proceeding from identification of MHC class I‐presented peptides to a comparative RNA expression survey of tumours and normal tissues. [ABSTRACT FROM AUTHOR]

Development of effective immunotherapy for chemoresistant malignancies can be advanced by studies in spontaneous cancer models, such as the dog. A crucial first step, T‐cell epitope discovery, can be assisted by determination of binding motifs of common dog leukocyte antigen (DLA) class Ia allotypes. Boxers are popular, inbred dogs with increased risks of relevant target cancers and restricted MHC diversity. We sought to identify the motif of DLA‐88*034:01, a breed‐dominant allotype, to assist peptide prediction from tumor antigens. Mass spectrometry of eluted peptides showed a preference for nonamers with conserved amino acid preferences: basic at position (P)1; hydrophobic at P2; acidic at P4; histidine at P6; and phenylalanine at P9. This data should expedite finding epitopes restricted by this DLA‐88 allotype. [ABSTRACT FROM AUTHOR]

Objectives: To identify any seasonal variation in the occurrence of, and outcome following Acute Kidney Injury.Methods: The study utilised the biochemistry based AKI electronic (e)-alert system established across the Welsh National Health Service to collect data on all AKI episodes to identify changes in incidence and outcome over one calendar year (1st October 2015 and the 30th September 2016).Results: There were total of 48 457 incident AKI alerts. The highest proportion of AKI episodes was seen in the quarter of January to March (26.2%), and the lowest in the quarter of October to December (23.3%, P < .001). The same trend was seen for both community-acquired and hospital-acquired AKI sub-sets. Overall 90 day mortality for all AKI was 27.3%. In contrast with the seasonal trend in AKI occurrence, 90 day mortality after the incident AKI alert was significantly higher in the quarters of January to March and October to December compared with the quarters of April to June and July to September (P < .001) consistent with excess winter mortality reported for likely underlying diseases which precipitate AKI.Conclusions: In summary we report for the first time in a large national cohort, a seasonal variation in the incidence and outcomes of AKI. The results demonstrate distinct trends in the incidence and outcome of AKI. [ABSTRACT FROM AUTHOR]

Background The 'Acute Resuscitation Plan' ( ARP) is a document for recording the resuscitation plans of patients at a tertiary hospital for adult patients. The ARP was introduced at the hospital in September 2014, superseding the 'Not for Cardiopulmonary Resuscitation ( CPR)' form. Unlike the Not for CPR form, the ARP was relevant to patients with and without resuscitation limits. Aim To evaluate the introduction of the ARP. Methods This study is a retrospective audit of the records of all admissions to the hospital from January to June 2014 (Not for CPR period) and January to June 2015 ( ARP period). The main outcomes are the incidence of resuscitation plans, the proportion of ARP specifying consultation with the patient (or representative) and with senior medical staff, and the proportion of ARP among older patients and those with significant comorbidity. Results Resuscitation plans were present for 453 of 23 325 (1.9%) admissions in the Not for CPR period versus 1801 of 24 037 (7.5%) in the ARP period (odds ratio ( OR) 4.1, 95% confidence interval ( CI) 3.7-4.5, P < 0.001). A total of 42% of ARP specified 'care of the dying' in the event of arrest. Acknowledgement of the views of the patient (or representative) was indicated on 37% of ARP and of a senior physician on 28%. An ARP was not present for 67% of patients aged ≥90 years, 59% from aged care, 90% with metastatic cancer and 64% aged ≥80 years and with a Charlson comorbidity index ≥3. Conclusions More patients had resuscitation plans after introducing the ARP. However, patients and senior physicians were often remote from the consultation process, and an ARP was not present for many patients likely to have a poor outcome from cardiopulmonary arrest. [ABSTRACT FROM AUTHOR]

Introduction and Aims The measurement of clinical outcomes is an important, but lacking, component of drug and alcohol treatment in Australia. This study aimed to psychometrically validate the Treatment Outcomes Profile under Australian conditions, examining implementation and feasibility issues in three public opioid treatment program clinics in NSW. Design and Methods The Treatment Outcomes Profile was modified to reflect Australian conditions and re-named the Australian Treatment Outcomes Profile ( ATOP). The ATOP was introduced into the participating clinics and administered by clinic staff at 3-month intervals as part of routine clinical practice. Participants completed a research interview, consisting of the ATOP and a suite of 'gold standard' instruments assessing substance use and related health and welfare domains, in the 72 h following completion of a routine clinical ATOP. The researcher- and clinician-administered ATOPs were compared to assess interrater reliability, and the researcher-administered ATOP and 'gold standard' instruments were compared to assess concurrent validity. Implementation and feasibility issues were assessed using questionnaires and focus groups with clinician and clients. Results The ATOP demonstrated acceptable concurrent validity and interrater reliability. It was well received by clients and clinicians, particularly for its ease of use, applicability and brevity. Conclusions The ATOP is a psychometrically valid instrument for the measurement of treatment outcomes in Australian opioid treatment populations and can feasibly be implemented as part of routine clinical practice in specialist opioid treatment program clinics. The role of the ATOP to measure outcomes in other drug and alcohol treatment modalities requires exploration. [Ryan A, Holmes J, Hunt V, Dunlop A, Mammen K, Holland R, Sutton Y, Sindhusake D, Rivas G & Lintzeris N. Validation and implementation of the Australian Treatment Outcomes Profile in specialist drug and alcohol settings. Drug Alcohol Rev 2014;33:33-42] [ABSTRACT FROM AUTHOR]

In seeking to understand the variation in asylum grant rates by immigration judges ( IJs), we apply a variation of the attitudinal model that we modify by incorporating a cognitive model of decision making, arguing that some pieces of information before IJs are treated objectively while others are treated subjectively. This model allows us to account for informational cues that influence decisions while assessing the impact of national interests and human rights conditions. We find that IJ policy predispositions play a dominant role, and that liberal IJs respond to applicant characteristics differently than conservatives, but also that the law constrains decision making. [ABSTRACT FROM AUTHOR]

Paracellular transport through the tight junction shows selectivity for both ionic charge and solute size. It is known that charged residues on the extracellular loops of claudins control charge selectivity. It is also known that inducible expression of claudin-2, but not claudin-4, will selectively increase the permeability for polyethylene glycol (PEG) molecules which are <0.4 Å in radius, but it is not known whether permeability is controlled by the same regions of claudins which control charge selectivity. Using inducible expression of chimeras of claudin-2 and claudin-4 in monolayers of MDCK II cells we show that the extracellular loops alone are responsible for controlling the permeability for noncharged PEGs as well as for charge selectivity. Further, the cytoplasmic C-terminal PDZ-binding motif is required for wild-type claudin-2 to control permeability, suggesting a requirement for attachment to the PDZ scaffold in order to form pores. These observations support a model where the loops form pores controlling permeability for both charged and noncharged solutes which are smaller than 0.4 Å. They leave unanswered why both claudin-2 and -4 can influence electrical properties while only -2 can selectively increase permeability for small PEGs. [ABSTRACT FROM AUTHOR]

Previous research on the Colombian illegal drug trade, which is generally qualitative in approach and focused on the national level, has concluded that the drug industry harms the economy. In order to test out this widespread claim, this article seeks to differentiate between the corrosive economic effects of Colombia's persistently high levels of generalised political violence and the specific consequences of the cocaine trade. It combines historical national level analysis with quantitative department analysis and identifies the economic effects of both paramilitary and guerrilla violence, thereby contributing to a closer examination of the impact of the drugs trade on the economy. The results reveal that paramilitary violence is related positively to exports but negatively to gross domestic product. Guerrilla violence, however, appears to harm exports but, surprisingly, not gross domestic product. Contrary to the conventional wisdom, coca cultivation does not have independent effects on exports or GDP, a conclusion which suggests that Colombia's economic problems stem more from political violence than from the drug trade in itself. [ABSTRACT FROM AUTHOR]

Abstract Quantitative trait loci (QTL) affecting the ability of the Eastern treehole mosquito, Ochlerotatus triseriatus , to transovarially transmit (TOT) La Crosse virus (LAC) were mapped in an F1 intercross. The Holmen strain of O. triseriatus , previously selected for TOT refractoriness, was crossed to the AIDL strain that had been selected for TOT permissiveness. In P1 and F1 parents and 49 F2 individuals, regions of 10 cDNA loci were analysed with single strand conformation polymorphism (SSCP) analysis to identify and orientate linkage groups. Genotypes were also scored at fifty-six random amplified polymorphic DNA (RAPD)-SSCP loci. Twenty-eight F2 offspring were individually analysed for TOT. Three QTL for TOT were detected with standard interval mapping on chromosomes II and III. Alleles at the three loci contributed additively towards determining the overall TOT rate and cumulatively accounted for ≈ 53% of the phenotypic variance in TOT. [ABSTRACT FROM AUTHOR]

Full activation of cyclin-dependent kinases (Cdks) requires binding to a cyclin and phosphorylation on an activating site equivalent to Thr160 in Cdk2 by the Cdk-activating kinase. Much is known about the effects of cyclin binding, but the role of the activating phosphorylation is less well understood. We have characterized the effects of Thr160 phosphorylation of Cdk2 on its interactions with substrates, particularly with the P + 3 position. We find that an ionic interaction participates in the recognition of the P + 3 position of the substrate and confirms an observation from structural studies indicating that a key element of this recognition is an interaction between the lysine at the P + 3 position and the Thr160 phosphate of Cdk2. The major effect of disrupting the lysine–phosphate interaction was on kcat values rather than Km values, suggesting that the energy from this interaction is used to align the substrate for efficient catalysis. A lack of effect of Thr160 phosphorylation on the ATPase activity of Cdk2 supported this interpretation. [ABSTRACT FROM AUTHOR]

Tight junctions (TJ) create charge and size-selective barriers for solutes in the paracellular pathway. The large claudin family determines ionic selectivity, however, the basis of size discrimination remains unknown. The purpose of our study was to compare the TJ size selectivity for uncharged solutes among several cell types and to determine whether claudins influence this parameter. We simultaneously determined the permeability (Papp) for a series of 22 polyethylene glycols (PEG) ranging in radius from ≈ 2.5-7 Å across cultured monolayers of renal tubular (LLC-PK1, MDCK II, MDCK C7), and intestinal (Caco-2) cells and porcine ileum. PEGs were quantified by post-flux labeling with 1-napthylisocyanate followed by HPLC-fluorescence detection. Papp showed a size discrimination extrapolating to an apparent pore radius of about 4 Å in all cell types and intestine. However, the number of pores varied widely among cell types and was unrelated to transepithelial electrical resistance (TEER). A second smaller capacity pathway was size-independent. Inducible expression of claudin-2 or 18, but not occludin, increased the number of small pores in MDCK II cells. Although claudins have previously been shown to regulate paracellular movement of charged ions and thus TEER, these new results are consistent with the idea that these same claudin pores also form a high capacity pathway for small uncharged solutes. [ABSTRACT FROM AUTHOR]