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1.
Sci Rep ; 14(1): 788, 2024 Jan 08.
Article in English | MEDLINE | ID: mdl-38191782

ABSTRACT

Geological disposal of radioactive waste is being planned by many countries. Bentonite clay is often included in facility design, providing a barrier to radionuclide migration. Gas, generated by the waste or corrosion of waste canisters, may disrupt the properties of the bentonite. Robust prediction of this interaction is, therefore, necessary to demonstrate safe facility evolution. In some cases, gas may deform the clay, resulting in localised flow; however, the nature of this deformation has been widely debated. Accurate numerical representation of this behaviour has been limited by a shortage of information on the degree/distribution of deformation. Using experimental data from gas injection tests in bentonite, we show that first order fluctuations in the stress field can provide this information. We show that hundreds of microdeformation events can be detected, with similar characteristics to established fracturing phenomena, including earthquakes and acoustic emissions. We also demonstrate that stress field disruption (i) is spatially localised and (ii) has characteristics consistent with gas pathway 'opening' and 'closure' as gas enters and exits the clay, respectively. This new methodology offers fundamental insight and a new opportunity to parameterise and constrain gas advection models in clays and shales, substantially improving our capacity for safe facility design.

2.
Mar Environ Res ; 191: 106171, 2023 Oct.
Article in English | MEDLINE | ID: mdl-37716280

ABSTRACT

Global climate change is projected to raise global temperatures by 3.3-5.7 °C by 2100, resulting in changes in species composition, abundance, and nutritional quality of organisms at the base of the marine food web. Predicted increases in prey availability and reductions in prey nutritional quality under climate warming in certain marine systems are expected to impact higher trophic levels, such as fish and humans. There is limited knowledge of the interplay between food quantity and quality under warming, specifically when food availability is high, but quality is low. Here, we conducted an experiment assessing the effects of food quality (fatty acid composition and ratios) on juvenile Chinook salmon's (Oncorhynchus tshawytscha) body and nutritional condition, specifically focusing on RNA:DNA ratio, Fulton's K, growth, mortality and their fatty acid composition. Experimental diets represented three different climate change scenarios with 1) a present-day diet (Euphausia pacifica), 2) a control diet (commercial aquaculture diet), and 3) a predicted Intergovernmental Panel on Climate Change (IPCC) worst-case scenario diet with low essential fatty acid concentrations (IPCC SSP5-8.5). We tested how growth rates, RNA:DNA ratio, Fulton's K index, fatty acid composition and mortality rates in juvenile Chinook salmon compared across diet treatments. Fatty acids were incorporated into the salmon muscle at varying rates but, on average, reflected dietary concentrations. High dietary concentrations of DHA, EPA and high DHA:EPA ratios, under the control and present-day diets, increased fish growth and condition. In contrast, low concentrations of DHA and EPA and low DHA:EPA ratios in the diets under climate change scenario were not compensated for by increased food quantity. This result highlights the importance of considering food quality when assessing fish response to changing ocean conditions.


Subject(s)
Climate Change , Salmon , Humans , Animals , Docosahexaenoic Acids , Fatty Acids , Fishes , Food Quality
3.
Open Heart ; 8(1)2021 04.
Article in English | MEDLINE | ID: mdl-33879507

ABSTRACT

OBJECTIVE: Most current cardiovascular disease (CVD) risk stratification tools are for people without CVD, but very few are for prevalent CVD. In this study, we developed and validated a CVD severity score in people with coronary heart disease (CHD) and evaluated the association between severity and adverse outcomes. METHODS: Primary and secondary care data for 213 088 people with CHD in 398 practices in England between 2007 and 2017 were used. The cohort was randomly divided into training and validation datasets (80%/20%) for the severity model. Using 20 clinical severity indicators (each assigned a weight=1), baseline and longitudinal CVD severity scores were calculated as the sum of indicators. Adjusted Cox and competing-risk regression models were used to estimate risks for all-cause and cause-specific hospitalisation and mortality. RESULTS: Mean age was 64.5±12.7 years, 46% women, 16% from deprived areas, baseline severity score 1.5±1.2, with higher scores indicating a higher burden of disease. In the training dataset, 138 510 (81%) patients were hospitalised at least once, and 39 944 (23%) patients died. Each 1-unit increase in baseline severity was associated with 41% (95% CI 37% to 45%, area under the receiver operating characteristics (AUROC) curve=0.79) risk for 1 year for all-cause mortality; 59% (95% CI 52% to 67%, AUROC=0.80) for cardiovascular (CV)/diabetes mortality; 27% (95% CI 26% to 28%) for any-cause hospitalisation and 37% (95% CI 36% to 38%) for CV/diabetes hospitalisation. Findings were consistent in the validation dataset. CONCLUSIONS: Higher CVD severity score is associated with higher risks for any-cause and cause-specific hospital admissions and mortality in people with CHD. Our reproducible score based on routinely collected data can help practitioners better prioritise management of people with CHD in primary care.


Subject(s)
Coronary Disease/diagnosis , Risk Assessment/methods , Cardiovascular Diseases/diagnosis , Cardiovascular Diseases/epidemiology , Cause of Death/trends , Coronary Angiography , Coronary Disease/epidemiology , England/epidemiology , Female , Follow-Up Studies , Humans , Male , Middle Aged , Morbidity/trends , Retrospective Studies , Risk Factors , Survival Rate/trends
4.
Ochsner J ; 21(4): 402-405, 2021.
Article in English | MEDLINE | ID: mdl-34984056

ABSTRACT

Background: Coronavirus disease 2019 (COVID-19) is recognized as a multisystem disease affecting the whole body, with new complications from the disease being described on an almost-daily basis. Case Report: We report the case of a 50-year-old female with a medical history of diabetes and silicone breast implants who developed right-sided, multicentric breast masses after a prolonged hospitalization for COVID-19 infection complicated by renal failure requiring dialysis. The patient noted an onset of breast pain and masses, and subsequent imaging demonstrated multiple similar oval masses. She underwent biopsy and operative debridement of the lesions and recovered appropriately. Results were consistent with sterile abscesses that were considered secondary to a vasculitis-like process associated with COVID-19 infection. Conclusion: To our knowledge, this case is the first account of breast pathology associated with a diagnosis of COVID-19 in the medical literature and encourages systematic evaluations of patients with coronavirus infections, including breast examinations.

5.
Sci Data ; 7(1): 332, 2020 10 06.
Article in English | MEDLINE | ID: mdl-33024126

ABSTRACT

The North Pacific Marine Salmon Diet Database is an open-access relational database built to centralize and make accessible salmon diet data through a standardized database structure. The initial data contribution contains 21,862 observations of salmon diet, and associated salmon biological parameters, prey biological parameters, and environmental data from the North Pacific Ocean. The data come from 907 unique spatial areas and mostly fall within two time periods, 1959-1969 and 1987-1997, during which there are more data available compared to other time periods. Data were extracted from 62 sources identified through a systematic literature review, targeting peer-reviewed and gray literature. The purpose of this database is to consolidate data into a common format to address gaps in our ecological understanding of the North Pacific Ocean, particularly with respect to salmon. This database can be used to address a variety of questions regarding salmon foraging, productivity, and marine survival. The North Pacific Marine Salmon Diet Database will continue to grow in the future as more data are digitized and become available.


Subject(s)
Diet/veterinary , Salmon , Animals , Databases, Factual , Pacific Ocean
6.
Microbiol Resour Announc ; 9(3)2020 Jan 16.
Article in English | MEDLINE | ID: mdl-31948970

ABSTRACT

Here, we report the genome sequence of Arthrobacter sp. strain RT-1, isolated from a cocktail of termite gut and rumen fluid. Strain RT-1 degrades a variety of lignin monomers and dimers as the growth substrates. The genome annotation predicted the genes necessary for the catabolism of lignin-derived aromatic compounds.

8.
Methods Mol Biol ; 2020: 91-114, 2019.
Article in English | MEDLINE | ID: mdl-31177494

ABSTRACT

ELISAs and similar immunoassays are a backbone of biomedical research and clinical practice. Here we review the major factors to consider in the development and application of ultrasensitive ELISAs for analysis of human immune responses in plasma, serum, urine, or tissue culture supernatants. We focus on cytokine and chemokine biomarkers of health and chronic inflammatory diseases including allergy, asthma, autoimmunity, and cardiovascular disease. Detailed protocols for ELISA and Meso Scale Discovery assays (an improved variant of ELISA) are provided for 15 cytokines and 11 chemokines that play immune-regulatory roles in human innate and adaptive immunity. Protocols have been individually optimized to yield ultrasensitive limits of detection and quantification. Major factors enhancing immunoassay sensitivity, precision, and reproducibility, as well as key pitfalls in assay design and execution, are critically reviewed.


Subject(s)
Biomarkers/analysis , Chemokines/analysis , Cytokines/analysis , Inflammation/immunology , Adaptive Immunity , Enzyme-Linked Immunosorbent Assay , Humans , Immunity, Innate , Plasma/immunology , Reproducibility of Results , Serum/immunology , Urine/chemistry
9.
Orphanet J Rare Dis ; 13(1): 155, 2018 09 05.
Article in English | MEDLINE | ID: mdl-30185236

ABSTRACT

BACKGROUND: Myotonic Dystrophy is the most common form of muscular dystrophy in adults, affecting an estimated 10 per 100,000 people. It is a multisystemic disorder affecting multiple generations with increasing severity. There are currently no licenced therapies to reverse, slow down or cure its symptoms. In 2009 TREAT-NMD (a global alliance with the mission of improving trial readiness for neuromuscular diseases) and the Marigold Foundation held a workshop of key opinion leaders to agree a minimal dataset for patient registries in myotonic dystrophy. Eight years after this workshop, we surveyed 22 registries collecting information on myotonic dystrophy patients to assess the proliferation and utility the dataset agreed in 2009. These registries represent over 10,000 myotonic dystrophy patients worldwide (Europe, North America, Asia and Oceania). RESULTS: The registries use a variety of data collection methods (e.g. online patient surveys or clinician led) and have a variety of budgets (from being run by volunteers to annual budgets over €200,000). All registries collect at least some of the originally agreed data items, and a number of additional items have been suggested in particular items on cognitive impact. CONCLUSIONS: The community should consider how to maximise this collective resource in future therapeutic programmes.


Subject(s)
Myotonic Dystrophy , Rare Diseases , Registries , Clinical Trials as Topic , Education , Humans
10.
PLoS One ; 12(6): e0177813, 2017.
Article in English | MEDLINE | ID: mdl-28636613

ABSTRACT

Changes in maternal innate immunity during healthy human pregnancy are not well understood. Whether basal immune status in vivo is largely unaffected by pregnancy, is constitutively biased towards an inflammatory phenotype (transiently enhancing host defense) or exhibits anti-inflammatory bias (reducing potential responsiveness to the fetus) is unclear. Here, in a longitudinal study of healthy women who gave birth to healthy infants following uncomplicated pregnancies within the Canadian Healthy Infant Longitudinal Development (CHILD) cohort, we test the hypothesis that a progressively altered bias in resting innate immune status develops. Women were examined during pregnancy and again, one and/or three years postpartum. Most pro-inflammatory cytokine expression, including CCL2, CXCL10, IL-18 and TNFα, was reduced in vivo during pregnancy (20-57%, p<0.0001). Anti-inflammatory biomarkers (sTNF-RI, sTNF-RII, and IL-1Ra) were elevated by ~50-100% (p<0.0001). Systemic IL-10 levels were unaltered during vs. post-pregnancy. Kinetic studies demonstrate that while decreased pro-inflammatory biomarker expression (CCL2, CXCL10, IL-18, and TNFα) was constant, anti-inflammatory expression increased progressively with increasing gestational age (p<0.0001). We conclude that healthy resting maternal immune status is characterized by an increasingly pronounced bias towards a systemic anti-inflammatory innate phenotype during the last two trimesters of pregnancy. This is resolved by one year postpartum in the absence of repeat pregnancy. The findings provide enhanced understanding of immunological changes that occur in vivo during healthy human pregnancy.


Subject(s)
Anti-Inflammatory Agents/immunology , Biomarkers/metabolism , Immunity, Innate/immunology , Inflammation Mediators/immunology , Inflammation/immunology , Adolescent , Adult , Anti-Inflammatory Agents/metabolism , Canada , Female , Gestational Age , Humans , Inflammation/metabolism , Inflammation/pathology , Inflammation Mediators/metabolism , Kinetics , Longitudinal Studies , Pregnancy , Young Adult
11.
Immun Inflamm Dis ; 5(3): 364-372, 2017 09.
Article in English | MEDLINE | ID: mdl-28544689

ABSTRACT

INTRODUCTION: Obesity during pregnancy is associated with meta-inflammation and an increased likelihood of clinical complications. Surgery results in intense, acute inflammatory responses in any individual. Because obese individuals exhibit constitutive inflammatory responses and high rates of Caesarian section, it is important to understand the impact of surgery in such populations. Whether more pronounced pro-inflammatory cytokine responses and/or counterbalancing changes in anti-inflammatory immune modulators occurs is unknown. Here we investigated innate immune capacity in vivo and in vitro in non-obese, term-pregnant controls versus healthy, term-pregnant obese women (Class II, BMI 35-40). METHODS: Systemic in vivo induction of eleven pro- and anti-inflammatory biomarkers and acute phase proteins was assessed in plasma immediately prior to and again following Caesarian section surgery. Independently, innate immune capacity was examined by stimulating freshly isolated PBMC in vitro with a panel of defined PRR-ligands for TLR4, TLR8, TLR3, and RLR 24 h post-surgery. RESULTS: The kinetics and magnitude of the in vivo inflammatory responses examined were indistinguishable in the two populations across the broad range of biomarkers examined, despite the fact that obese women had higher baseline inflammatory status. Deliberate in vitro stimulation with a range of PRR ligands also elicited pro- and anti-inflammatory cytokine responses that were indistinguishable between control and obese mothers. CONCLUSIONS: Acute in vivo innate immune responses to C-section, as well as subsequent in vitro stimulation with a panel of microbial mimics, are not detectably altered in Class II obese women. The data argue that while Class II obesity is undesirable, it has minimal impact on the in vivo inflammatory response, or innate immunomodulatory capacity, in women selecting C-section.


Subject(s)
Cesarean Section , Immunity, Innate , Obesity/immunology , Pregnancy Complications/immunology , Adult , Female , Humans , Obesity/pathology , Pregnancy , Pregnancy Complications/pathology
12.
Womens Health Issues ; 26(1): 48-54, 2016.
Article in English | MEDLINE | ID: mdl-26777283

ABSTRACT

BACKGROUND: Adolescent girls involved with the juvenile justice system have higher rates of sexually transmitted infections and pregnancy than their nondetained peers. Although they may receive reproductive health care while detained, following clinician recommendations and accessing services in the community can be challenging. OBJECTIVES: This study aimed to determine the barriers this population faces 1) accessing reproductive health care and 2)following the recommendations they receive when they are in the community. METHODS: Adolescent girls at a juvenile detention facility completed online surveys about their demographics and sexual health behaviors. A subsequent semistructured interview assessed their experiences with reproductive health care services. RESULTS: Twenty-seven girls aged 14 to 19 were interviewed. The majority (86%) self-reported as Latina or Hispanic. The average age of sexual debut was 13.8 years. The major interview themes were 1) personal priorities and motivations affect decision making, 2) powerful external voices influence reproductive health choices, 3) accessing services "on the run" is particularly challenging, and 4) detention represents an opportunity for intervention and change. CONCLUSION: Adolescent girls who are detained within the juvenile justice system face reproductive health challenges that vary with their life circumstances. They frequently have priorities, external voices, and situations that influence their decisions. Clinicians who care for these young women are in a unique position to address their health needs. Eliciting girls' goals, beliefs, and influences through motivational interviewing, as well as developing targeted interventions based on their unique experiences, may be particularly helpful for this population.


Subject(s)
Health Services Accessibility/statistics & numerical data , Health Services Needs and Demand/statistics & numerical data , Juvenile Delinquency , Sexual Behavior , Adolescent , Female , Health Behavior , Health Care Surveys , Humans , Interviews as Topic , Pregnancy , Pregnancy in Adolescence/prevention & control , Reproductive Health Services/organization & administration , Reproductive Health Services/statistics & numerical data , Sexually Transmitted Diseases/prevention & control , United States/epidemiology , Women's Health , Young Adult
13.
Stud Health Technol Inform ; 214: 8-14, 2015.
Article in English | MEDLINE | ID: mdl-26210411

ABSTRACT

Clinical decisions rely on expert knowledge that draws on quality patient phenotypic and physiological data. In this regard, systems that can support patient-centric care are essential. Patient registries are a key component of patient-centre care and can come in many forms such as disease-specific, recruitment, clinical, contact, post market and surveillance. There are, however, a number of significant challenges to overcome in order to maximise the utility of these information management systems to facilitate improved patient-centred care. Registries need to be harmonised regionally, nationally and internationally. However, the majority are implemented as standalone systems without consideration for data standards or system interoperability. Hence the task of harmonisation can become daunting. Fortunately, there are strategies to address this. In this paper, a disease registry framework is outlined that enables efficient deployment of national and international registries that can be modified dynamically as registry requirements evolve. This framework provides a basis for the development and implementation of data standards and enables patients to seamlessly belong to multiple registries. Other significant advances include the ability for registry curators to create and manage registries themselves without the need to contract software developers, and the concept of a registry description language for ease of registry template sharing.


Subject(s)
Disease/classification , Electronic Health Records/organization & administration , Epidemiologic Methods , Models, Organizational , Patient-Centered Care/organization & administration , Registries , Information Storage and Retrieval/methods , Medical Record Linkage/methods , Western Australia
14.
Orphanet J Rare Dis ; 10: 54, 2015 May 06.
Article in English | MEDLINE | ID: mdl-25943355

ABSTRACT

BACKGROUND: People with neuromuscular disorders (NMD) exhibit weak coughs and are susceptible to recurrent chest infections and acute respiratory complications, the most frequent reasons for their unplanned hospital admissions. Mechanical insufflation-exsufflation (MI-E) devices are a non-invasive method of increasing peak cough flow, improving cough efficacy, the clearance of secretion and overcoming atelectasis. There is limited published evidence on the impact of home use MI-E devices on health service utilisation. The aims of the study were: to assess the self-reported health and lifestyle benefits experienced as a result of home use of MI-E devices; and evaluate the effects of in-home use of MI-E devices on Emergency Department (ED) presentations, hospital admissions and inpatient length of stay (LOS). METHODS: Individuals with NMD who were accessing a home MI-E device provided through Muscular Dystrophy Western Australia were invited to participate in a quantitative survey to obtain information on their experiences and self-assessed changes in respiratory health. An ad-hoc record linkage was performed to extract hospital, ED and mortality data from the Western Australian Department of Health (DOHWA). The main outcome measures were ED presentations, hospital separations and LOS, before and after commencement of home use of an MI-E device. RESULTS: Thirty seven individuals with NMD using a MI-E device at home consented to participate in this study. The majority (73%) of participants reported using the MI-E device daily or weekly at home without medical assistance and 32% had used the machine to resolve a choking episode. The survey highlighted benefits to respiratory function maintenance and the ability to manage increased health care needs at home. Not using a home MI-E device was associated with an increased risk of ED presentations (RR = 1.76, 95% CI 1.1-2.84). The number of hospital separations and LOS reduced after the use of MI-E device, but not significantly. No deaths were observed in participants using the MI-E device at home. CONCLUSIONS: Home use of a MI-E device by people living with NMD may have a potential impact on reducing their health service utilisation and risk of death. Future research with greater subject numbers and longer follow-up periods is recommended to enhance this field of study.


Subject(s)
Airway Obstruction/etiology , Airway Obstruction/therapy , Insufflation/instrumentation , Life Style , Neuromuscular Diseases/complications , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male , Middle Aged , Quality of Life , Safety , Young Adult
15.
J Clin Urol ; 8(3): 177-182, 2015 May.
Article in English | MEDLINE | ID: mdl-27867520

ABSTRACT

OBJECTIVE: The objective of this article is to assess the readability of leaflets about urological procedures provided by the British Association of Urological Surgeons (BAUS) to evaluate their suitability for providing information. METHODS: Information leaflets were assessed using three measures of readability: Flesch Reading Ease, Flesch-Kincaid and Simple Measure of Gobbledygook (SMOG) grade formulae. The scores were compared with national literacy statistics. RESULTS: Relatively good readability was demonstrated using the Flesch Reading Ease (53.4-60.1) and Flesch-Kincaid Grade Level (6.5-7.6) methods. However, the average SMOG index (14.0-15.0) for each category suggests that the majority of the leaflets are written above the reading level of an 18-year-old. Using national literacy statistics, at least 43% of the population will have significant difficultly understanding the majority of these leaflets. CONCLUSIONS: The results suggest that comprehension of the leaflets provided by the BAUS is likely to be poor. These leaflets may be used as an adjunct to discussion but it is essential to ensure that all the information necessary to make an informed decision has been conveyed in a way that can be understood by the patient.

16.
J Biol Chem ; 281(17): 12102-11, 2006 Apr 28.
Article in English | MEDLINE | ID: mdl-16505477

ABSTRACT

Activation loop phosphorylation plays critical regulatory roles for many kinases. Unlike other protein kinase Cs (PKC), PKC-delta does not require phosphorylation of its activation loop (Thr-507) for in vitro activity. We investigated the structural basis for this unusual capacity and its relevance to PKC-delta function in intact cells. Mutational analysis demonstrated that activity without Thr-507 phosphorylation depends on 20 residues N-terminal to the kinase domain and a pair of phenylalanines (Phe-500/Phe-527) unique to PKC-delta in/near the activation loop. Molecular modeling demonstrated that these elements stabilize the activation loop by forming a hydrophobic chain of interactions from the C-lobe to activation loop to N-terminal (helical) extension. In cells PKC-delta mediates both apoptosis and transcription regulation. We found that the T507A mutant of the PKC-delta kinase domain resembled the corresponding wild type in mediating apoptosis in transfected HEK293T cells. But the T507A mutant was completely defective in AP-1 and NF-kappaB reporter assays. A novel assay in which the kinase domain of PKC-delta and its substrate (a fusion protein of PKC substrate peptide with green fluorescent protein) were co-targeted to lipid rafts revealed a major substrate-selective defect of the T507A mutant in phosphorylating the substrate in cells. In vitro analysis showed strong product inhibition on the T507A mutant with particular substrates whose characteristics suggest it contributes to the substrate selective defect of the PKC-delta T507A mutant in cells. Thus, activation loop phosphorylation of PKC-delta may regulate its function in cells in a novel way.


Subject(s)
Mutation/genetics , Protein Kinase C-delta/metabolism , Apoptosis , Cells, Cultured , Enzyme Activation , Humans , Kidney/enzymology , Models, Molecular , NF-kappa B/genetics , NF-kappa B/metabolism , Phenylalanine/chemistry , Phenylalanine/genetics , Phosphorylation , Protein Kinase C-delta/chemistry , Protein Kinase C-delta/genetics , Transcription Factor AP-1/metabolism , Transfection
17.
FASEB J ; 20(2): 383-5, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16354724

ABSTRACT

Microarray-based gene expression analysis demonstrated that laser photocoagulation (LPC) of mouse eyes had a long-term effect on the expression of genes functionally related to tissue repair, cell migration, proliferation, ion, protein and nucleic acid metabolism, cell signaling, and angiogenesis. Six structural genes, including five crystallins (Cryaa, Cryba1, Crybb2, Crygc, Crygs) and keratin 1-12 (Krt1-12), the anti-angiogenic factor thrombospondin 1 (Tsp1), the retina- and brain-specific putative transcription factor tubby-like protein 1 (Tulp1), and transketolase (Tkt), a key enzyme in the pentose-phosphate pathway, were all shown to be up-regulated by real-time PCR and/or Western blotting. Immunohistochemistry localized five of these proteins to the laser lesions and surrounding tissue within the retina and pigmented epithelium. This is the first study demonstrating long-term changes in the expression of these genes associated with LPC. Therefore, it suggests that modulated gene expression might contribute to the long-term inhibitory effect of LPC. In addition, these genes present novel targets for gene-based therapies aimed at treating microangiopathies, especially diabetic retinopathy, a disease currently only treatable with LPC.


Subject(s)
Eye Proteins/genetics , Eye Proteins/radiation effects , Gene Expression Profiling , Gene Expression Regulation/radiation effects , Laser Coagulation , Animals , Eye Proteins/metabolism , Female , Mice , Mice, Inbred C57BL , Pigment Epithelium of Eye/metabolism , Pigment Epithelium of Eye/radiation effects , Retina/metabolism , Retina/radiation effects , Time Factors
18.
Biochem J ; 394(Pt 1): 67-75, 2006 Feb 15.
Article in English | MEDLINE | ID: mdl-16241904

ABSTRACT

RALDH3 (retinal dehydrogenase 3) was characterized by kinetic and binding studies, protein engineering, homology modelling, ligand docking and electrostatic-potential calculations. The major recognition determinant of an RALDH3 substrate was shown to be an eight-carbon chain bonded to the aldehyde group whose kinetic influence (kcat/Km at pH 8.5) decreases when shortened or lengthened. Surprisingly, the b-ionone ring of all-trans-retinal is not a major recognition site. The dissociation constants (Kd) of the complexes of RALDH3 with octanal, NAD+ and NADH were determined by intrinsic tryptophan fluorescence. The similarity of the Kd values for the complexes with NAD+ and with octanal suggests a random kinetic mechanism for RALDH3, in contrast with the ordered sequential mechanism often associated with aldehyde dehydrogenase enzymes. Inhibition of RALDH3 by tri-iodothyronine binding in competition with NAD+, predicted by the modelling, was established kinetically and by immunoprecipitation. Mechanistic implications of the kinetically influential ionizations with macroscopic pKa values of 5.0 and 7.5 revealed by the pH-dependence of kcat are discussed. Analogies with data for non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase from Streptococcus mutans, together with the present modelled structure of the thioacyl RALDH3, suggest (a) that kcat characterizes deacylation of this intermediate for specific substrates and (b) the assignment of the pKa of the major ionization (approximating to 7.5) to the perturbed carboxy group of Glu280 whose conjugate base is envisaged as supplying general base catalysis to attack of a water molecule. The macroscopic pKa of the minor ionization (5.0) is considered to approximate to that of the carboxy group of Glu488.


Subject(s)
Aldehyde Oxidoreductases/metabolism , Aldehyde Oxidoreductases/chemistry , Amino Acid Sequence , Animals , Cell Line , Cloning, Molecular , Hydrogen-Ion Concentration , Kinetics , Mice , Models, Molecular , Mutagenesis, Site-Directed , Protein Binding , Retinal Dehydrogenase , Sequence Alignment , Sequence Homology, Amino Acid , Substrate Specificity , Triiodothyronine/metabolism
20.
Dent Update ; 32(8): 477-8, 481-2, 485, 2005 Oct.
Article in English | MEDLINE | ID: mdl-16262036

ABSTRACT

Methadone is a synthetic opiate used in the treatment of opiate addiction. Various side-effects have been associated with the use of methadone. These include xerostomia, which can contribute to a high caries rate. The UK Regional Drug Misuse Database reported that around 118,500 drug users were receiving treatment from drug misuse agencies and GPs. The vast majority (87%) were receiving treatment from community specialist services. As many drug abusers have poor oral health, general dental practitioners are likely to encounter such individuals. It is essential therefore that dentists are aware of the potential difficulties that may be encountered when treating subjects receiving methadone. These problems may relate to previous drug abuse and to the effects of methadone therapy.


Subject(s)
Dental Care , Methadone/adverse effects , Narcotics/adverse effects , Opioid-Related Disorders/rehabilitation , Dental Caries/etiology , HIV Infections/transmission , Hepatitis C/transmission , Humans , Substance Abuse, Intravenous/complications
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