116 research outputs found
Oligopeptide transport across the basolateral membrane of rat small intestine.
Oligopeptide transport in rat small intestine has been studied in intact tissue,
using the luminally and vascularly perfused isolated jejunum in situ technique, and a
hydrolysis-resistant dipeptide (D-Phe-L-Gln). The data in this thesis can be divided
into two main sections: (l) identification of the transporter proteins, and (2)
short-term regulation of transport.
The basolateral peptide transporter protein has not, to date, been identified. A
candidate protein was identified from membrane vesicles by a photo affinity labelling
technique using a dipeptide derivative ([4-azido-3,5-3H-D-Phe]-L-Ala), previously
shown to be an efficient substrate for the basolateral transporter. The labelled
candidate protein was successfully isolated by 2-DE, which revealed an apparent Mr
of 112 ± 2 kDa and a pI of approximately 6.5. Initial sequence analysis, tryptic
digestion followed by MALDI-TOF analysis and Q-TOF fragmentation of a tryptic
peptide, produced a peptide fingerprint and a sequence tag of 9 amino acids,
respectively, which, together, did not completely and conclusively match to any
known protein sequence contained within databases, therefore suggesting that the
112 kDa protein may be novel.
Short-term regulation of peptide transport was also investigated using the
vascular perfusion method. An amino acid-sensing pathway was discovered, using
L-Leucine as the regulator, involving protein kinase cacades leading to p70S6k
activation and subsequent stimulation ofbasolateral membrane peptide transport.
A major conclusion arising from the data was the distinction between PepTl
and the basolateral transporter, i.e. the sequence data obtained from the candidate
protein did not match to the PepTl sequence; in addition there appeared to be distinct
mechanisms of regulatory control at the two membranes.
Efficient delivery of peptidomimetic drugs when adminsitered by the oral
route requires knowledge of short-term regulation of intestinal peptide transport, in
addition to the sequence and structure of the basolateral transporter. This thesis
provides essential information, which may eventually contribute to the unequivocal
identification and sequencing of the intestinal basolateral peptide transporter, ultimately leading to the future development of compounds with high bioavailability
Development of a peer support intervention to encourage dietary behaviour change towards a Mediterranean diet in adults at high cardiovascular risk.
BACKGROUND: Mediterranean diet (MD) interventions are demonstrated to significantly reduce cardiovascular disease (CVD) risk but are typically resource intensive and delivered by health professionals. There is considerable interest to develop interventions that target sustained dietary behaviour change and that are feasible to scale-up for wider public health benefit. The aim of this paper is to describe the process used to develop a peer support intervention to encourage dietary behaviour change towards a MD in non-Mediterranean adults at high CVD risk. METHODS: The Medical Research Council (MRC) and Behaviour Change Wheel (BCW) frameworks and the COM-B (Capability, Opportunity, Motivation, Behaviour) theoretical model were used to guide the intervention development process. We used a combination of evidence synthesis and qualitative research with the target population, health professionals, and community health personnel to develop the intervention over three main stages: (1) we identified the evidence base and selected dietary behaviours that needed to change, (2) we developed a theoretical basis for how the intervention might encourage behaviour change towards a MD and selected intervention functions that could drive the desired MD behaviour change, and (3) we defined the intervention content and modelled outcomes. RESULTS: A theory-based, culturally tailored, peer support intervention was developed to specifically target behaviour change towards a MD in the target population. The intervention was a group-based program delivered by trained peer volunteers over 12-months, and incorporated strategies to enhance social support, self-efficacy, problem-solving, knowledge, and attitudes to address identified barriers to adopting a MD from the COM-B analysis. CONCLUSIONS: The MRC and BCW frameworks provided a systematic and complementary process for development of a theory-based peer support intervention to encourage dietary behaviour change towards a MD in non-Mediterranean adults at high CVD risk. The next step is to evaluate feasibility, acceptability, and diet behaviour change outcomes in response to the peer support intervention (change towards a MD and nutrient biomarkers) using a randomized controlled trial design
Achieving Teaching, Scholarship, and Service through Community Engagement
Occupational therapy faculty currently face enormous challenges in meeting teaching load expectations, while also under pressure to participate in scholarly projects and to make administrative and service contributions. Community engagement projects may provide opportunities for faculty to effectively and efficiently meet the goals in each of these areas while imparting benefits to students and community partners as well. Faculty at the Department of Occupational Therapy (OT) at Virginia Commonwealth University (VCU) embraced this idea as consistent with the university’s mission and strategic plan, and recognized its benefits in assisting faculty to meet workload demands. Four community partnerships reflecting the range and diversity of populations currently involved are highlighted: the Children’s Museum of Richmond, Rebuilding Together-Richmond, the William Nelson Bland Literacy Center, and Gateway Homes of Richmond. The developmental process and resulting benefits are described for each of these partnerships, and the paper concludes with lessons learned from these collaborative efforts. From these examples, it appears important to be proactive about developing community partnerships and realistic about the challenges of collaboration, but also to be aware of the role community engagement plays in creatively blending the potentially conflicting demands on faculty time
The clinical profile of tuberous sclerosis complex (TSC) in the United Kingdom: A retrospective cohort study in the Clinical Practice Research Datalink (CPRD)
AbstractBackgroundTuberous Sclerosis Complex (TSC) is a multi-system genetic disorder characterised by the development of benign growths and diverse clinical manifestations, varying in severity, age at onset and with high clinical burden.AimsThis longitudinal study aims to describe the broad spectrum of clinical manifestation profiles in a large, representative cohort of TSC patients in the UK in order to better understand disease complexity.MethodsTSC patients in the Clinical Practice Research Datalink (CPRD) and linked Hospital Episodes Statistics (CPRD-HES) were retrospectively identified between 1987 and 2013. Available history was extracted for each patient and clinical diagnosis, procedure and medication records reviewed. A random selection of patients from the CPRD-HES was used as a Comparator cohort.ResultsThree hundred and thirty-four TSC patients with a mean (SD) age of 30.3 (18.6) years were identified (53% female). TSC was diagnosed at mean age 3.2 (4.2) years. Epilepsy and psychiatric manifestations were reported frequently in paediatric (77% and 55%, respectively) and adult patients (66% and 68%, respectively). The prevalence of manifestations in the TSC cohort was markedly higher versus the Comparator cohort. The majority of paediatric (46%) and adult TSC patients (62%) developed clinical manifestations affecting at least three organ systems and forty-nine distinctive organ system manifestation profiles were identified.ConclusionsTSC patients present with multiple and complex clinical manifestations and profiles that necessitate the co-ordinated action of a multidisciplinary team in order to improve the quality and efficiency of care
Genome-wide association study identifies risk loci for progressive chronic lymphocytic leukemia
Prognostication in patients with chronic lymphocytic leukemia (CLL) is challenging due to heterogeneity in clinical course. We hypothesize that constitutional genetic variation affects disease progression and could aid prognostication. Pooling data from seven studies incorporating 842 cases identifies two genomic locations associated with time from diagnosis to treatment, including 10q26.13 (rs736456, hazard ratio (HR) = 1.78, 95% confidence interval (CI) = 1.47–2.15; P = 2.71 × 10−9) and 6p (rs3778076, HR = 1.99, 95% CI = 1.55–2.55; P = 5.08 × 10−8), which are particularly powerful prognostic markers in patients with early stage CLL otherwise characterized by low-risk features. Expression quantitative trait loci analysis identifies putative functional genes implicated in modulating B-cell receptor or innate immune responses, key pathways in CLL pathogenesis. In this work we identify rs736456 and rs3778076 as prognostic in CLL, demonstrating that disease progression is determined by constitutional genetic variation as well as known somatic drivers
Adjuvant chemotherapy for resected early-stage non-small cell lung cancer
BACKGROUND: To evaluate the effects of administering chemotherapy following surgery, or following surgery plus radiotherapy (known as adjuvant chemotherapy) in patients with early stage non-small cell lung cancer (NSCLC),we performed two systematic reviews and meta-analyses of all randomised controlled trials using individual participant data. Results were first published in The Lancet in 2010.
OBJECTIVES: To compare, in terms of overall survival, time to locoregional recurrence, time to distant recurrence and recurrence-free survival:A. Surgery versus surgery plus adjuvant chemotherapyB. Surgery plus radiotherapy versus surgery plus radiotherapy plus adjuvant chemotherapyin patients with histologically diagnosed early stage NSCLC.(2)To investigate whether or not predefined patient subgroups benefit more or less from cisplatin-based chemotherapy in terms of survival.
SEARCH METHODS: We supplemented MEDLINE and CANCERLIT searches (1995 to December 2013) with information from trial registers, handsearching relevant meeting proceedings and by discussion with trialists and organisations.
SELECTION CRITERIA: We included trials of a) surgery versus surgery plus adjuvant chemotherapy; and b) surgery plus radiotherapy versus surgery plus radiotherapy plus adjuvant chemotherapy, provided that they randomised NSCLC patients using a method which precluded prior knowledge of treatment assignment.
DATA COLLECTION AND ANALYSIS: We carried out a quantitative meta-analysis using updated information from individual participants from all randomised trials. Data from all patients were sought from those responsible for the trial. We obtained updated individual participant data (IPD) on survival, and date of last follow-up, as well as details of treatment allocated, date of randomisation, age, sex, histological cell type, stage, and performance status. To avoid potential bias, we requested information for all randomised patients, including those excluded from the investigators' original analyses. We conducted all analyses on intention-to-treat on the endpoint of survival. For trials using cisplatin-based regimens, we carried out subgroup analyses by age, sex, histological cell type, tumour stage, and performance status.
MAIN RESULTS: We identified 35 trials evaluating surgery plus adjuvant chemotherapy versus surgery alone. IPD were available for 26 of these trials and our analyses are based on 8447 participants (3323 deaths) in 34 trial comparisons. There was clear evidence of a benefit of adding chemotherapy after surgery (hazard ratio (HR)= 0.86, 95% confidence interval (CI)= 0.81 to 0.92, p< 0.0001), with an absolute increase in survival of 4% at five years.We identified 15 trials evaluating surgery plus radiotherapy plus chemotherapy versus surgery plus radiotherapy alone. IPD were available for 12 of these trials and our analyses are based on 2660 participants (1909 deaths) in 13 trial comparisons. There was also evidence of a benefit of adding chemotherapy to surgery plus radiotherapy (HR= 0.88, 95% CI= 0.81 to 0.97, p= 0.009). This represents an absolute improvement in survival of 4% at five years.For both meta-analyses, we found similar benefits for recurrence outcomes and there was little variation in effect according to the type of chemotherapy, other trial characteristics or patient subgroup.We did not undertake analysis of the effects of adjuvant chemotherapy on quality of life and adverse events. Quality of life information was not routinely collected during the trials, but where toxicity was assessed and mentioned in the publications, it was thought to be manageable. We considered the risk of bias in the included trials to be low.
AUTHORS' CONCLUSIONS: Results from 47 trial comparisons and 11,107 patients demonstrate the clear benefit of adjuvant chemotherapy for these patients, irrespective of whether chemotherapy was given in addition to surgery or surgery plus radiotherapy. This is the most up-to-date and complete systematic review and individual participant data (IPD) meta-analysis that has been carried out
Noninvasive Fetal Genotyping by Droplet Digital PCR to Identify Maternally Inherited Monogenic Diabetes Variants
Background: Babies of women with heterozygous pathogenic glucokinase (GCK) variants causing mild fasting hyperglycemia are at risk of macrosomia if they do not inherit the variant. Conversely, babies who inherit a pathogenic hepatocyte nuclear factor 4α (HNF4A) diabetes variant are at increased risk of high birth weight. Noninvasive fetal genotyping for maternal pathogenic variants would inform pregnancy management.
Methods: Droplet digital PCR was used to quantify reference and variant alleles in cell-free DNA extracted from blood from 38 pregnant women heterozygous for a GCK or HNF4A variant and to determine fetal fraction by measurement of informative maternal and paternal variants. Droplet numbers positive for the reference/alternate allele together with the fetal fraction were used in a Bayesian analysis to derive probability for the fetal genotype. The babies' genotypes were ascertained postnatally by Sanger sequencing.
Results: Droplet digital PCR assays for GCK or HNF4A variants were validated for testing in all 38 pregnancies. Fetal fraction of ≥2% was demonstrated in at least 1 cell-free DNA sample from 33 pregnancies. A threshold of ≥0.95 for calling homozygous reference genotypes and ≤0.05 for heterozygous fetal genotypes allowed correct genotype calls for all 33 pregnancies with no false-positive results. In 30 of 33 pregnancies, a result was obtained from a single blood sample.
Conclusions: This assay can be used to identify pregnancies at risk of macrosomia due to maternal monogenic diabetes variants.This article is freely available via Open Access. Click on the Publisher URL to access it via the publisher's site.A.T. Hattersley and M.H. Shepherd are supported by the NIHR Exeter Clinical Research Facility, which is a partnership between the University of Exeter Medical School College of Medicine and Health, and Royal Devon and Exeter NHS Foundation Trust
Genome-wide association study identifies risk loci for progressive chronic lymphocytic leukemia
Abstract: Prognostication in patients with chronic lymphocytic leukemia (CLL) is challenging due to heterogeneity in clinical course. We hypothesize that constitutional genetic variation affects disease progression and could aid prognostication. Pooling data from seven studies incorporating 842 cases identifies two genomic locations associated with time from diagnosis to treatment, including 10q26.13 (rs736456, hazard ratio (HR) = 1.78, 95% confidence interval (CI) = 1.47–2.15; P = 2.71 × 10−9) and 6p (rs3778076, HR = 1.99, 95% CI = 1.55–2.55; P = 5.08 × 10−8), which are particularly powerful prognostic markers in patients with early stage CLL otherwise characterized by low-risk features. Expression quantitative trait loci analysis identifies putative functional genes implicated in modulating B-cell receptor or innate immune responses, key pathways in CLL pathogenesis. In this work we identify rs736456 and rs3778076 as prognostic in CLL, demonstrating that disease progression is determined by constitutional genetic variation as well as known somatic drivers
International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways
Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n1⁄42,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n1⁄43,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombinedo5108) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine–cytokine pathways, for which relevant therapies exist
Challenges in the Pharmacologic Management of Obesity and Secondary Dyslipidemia in Children and Adolescents
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