97 research outputs found
A DNA minor groove electronegative potential genome map based on photo-chemical probing
The double-stranded DNA of the genome contains both sequence information directly relating to the protein and RNA coding as well as functional and structural information relating to protein recognition. Only recently is the importance of DNA shape in this recognition process being fully appreciated, and it also appears that minor groove electronegative potential may contribute significantly in guiding proteins to their cognate binding sites in the genome. Based on the photo-chemical probing results, we have derived an algorithm that predicts the minor groove electronegative potential in a DNA helix of any given sequence. We have validated this model on a series of protein–DNA binding sites known to involve minor groove electrostatic recognition as well as on stable nucleosome core complexes. The algorithm allows for the first time a full minor groove electrostatic description at the nucleotide resolution of any genome, and it is illustrated how such detailed studies of this sequence dependent, inherent property of the DNA may reflect on genome organization, gene expression and chromosomal condensation
'I feel like I am being stabbed by a thousand tiny men’: The challenges of communicating endometriosis pain
Endometriosis, as a widespread gynecological condition, affects an estimated 1 in 10 women and yet has a worldwide average diagnosis length of 7.5 years. Causing incapacitating pain, among other associated manifestations, the condition severely impacts on women’s lives. This article uses online survey data to investigate how pre-diagnosis endometriosis pain is conceptualized and articulated in order to explore communication challenges reported in early consultations that can potentially be seen to play a role in diagnosis delay. The findings of this study indicate that women feel that they do not have the appropriate tools to describe their pain and, in many instances, feel dismissed therefore prolonging diagnosis. The article finds that the majority of the pain descriptors identified use elaborate metaphorical scenarios to convey the intensity of the pain and concludes with some reflections on the issue of metaphorical language in endometriosis pain communication practices while calling for interdisciplinary work in order to devise appropriate tools for endometriosis pain communication
Interplay of Protein and DNA Structure Revealed in Simulations of the lac Operon
The E. coli Lac repressor is the classic textbook example of a protein that attaches to widely spaced sites along a genome and forces the intervening DNA into a loop. The short loops implicated in the regulation of the lac operon suggest the involvement of factors other than DNA and repressor in gene control. The molecular simulations presented here examine two likely structural contributions to the in-vivo looping of bacterial DNA: the distortions of the double helix introduced upon association of the highly abundant, nonspecific nucleoid protein HU and the large-scale deformations of the repressor detected in low-resolution experiments. The computations take account of the three-dimensional arrangements of nucleotides and amino acids found in crystal structures of DNA with the two proteins, the natural rest state and deformational properties of protein-free DNA, and the constraints on looping imposed by the conformation of the repressor and the orientation of bound DNA. The predicted looping propensities capture the complex, chain-length-dependent variation in repression efficacy extracted from gene expression studies and in vitro experiments and reveal unexpected chain-length-dependent variations in the uptake of HU, the deformation of repressor, and the folding of DNA. Both the opening of repressor and the presence of HU, at levels approximating those found in vivo, enhance the probability of loop formation. HU affects the global organization of the repressor and the opening of repressor influences the levels of HU binding to DNA. The length of the loop determines whether the DNA adopts antiparallel or parallel orientations on the repressor, whether the repressor is opened or closed, and how many HU molecules bind to the loop. The collective behavior of proteins and DNA is greater than the sum of the parts and hints of ways in which multiple proteins may coordinate the packaging and processing of genetic information. © 2013 Czapla et al
Miniature Schnauzers under primary veterinary care in the UK in 2013: demography, mortality and disorders
Individual dog breeds are often reported as predisposed to specific breed-related disorders but reliable epidemiological data on disease prevalence are sparse. The Miniature Schnauzer in the UK is a popular small breed dog that is often considered as relatively healthy and long-lived, but is this really true? This study aimed to use data from the VetCompass™ Programme at the Royal Veterinary College to characterise the demography, mortality and common disorders of the general population of Miniature Schnauzers under veterinary care in the UK
Hemodialysis Removes Uremic Toxins That Alter the Biological Actions of Endothelial Cells
Chronic kidney disease is linked to systemic inflammation and to an increased risk of ischemic heart disease and atherosclerosis. Endothelial dysfunction associates with hypertension and vascular disease in the presence of chronic kidney disease but the mechanisms that regulate the activation of the endothelium at the early stages of the disease, before systemic inflammation is established remain obscure. In the present study we investigated the effect of serum derived from patients with chronic kidney disease either before or after hemodialysis on the activation of human endothelial cells in vitro, as an attempt to define the overall effect of uremic toxins at the early stages of endothelial dysfunction. Our results argue that uremic toxins alter the biological actions of endothelial cells and the remodelling of the extracellular matrix before signs of systemic inflammatory responses are observed. This study further elucidates the early events of endothelial dysfunction during toxic uremia conditions allowing more complete understanding of the molecular events as well as their sequence during progressive renal failure
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Type 1 diabetes : The autoimmune process and islet transplantation
Type 1 diabetes (T1D) is an autoimmune disease characterized by the
selective loss of the insulin-producing β-cells residing in the islets of
Langerhans in the pancreas. Cytokines are involved in diabetes
development in the nonobese diabetic (NOD) mouse model. NOD mice
over-expressing the suppressor of cytokine signaling (SOCS-1)
specifically in the β-cells are protected from T1D. Previous studies
showed that immune cells infiltrated the pancreas of SOCS-1-transgenic
(tg) mice, however, infiltrating T cells were less pathogenic than those
infiltrating the islets in non-tg NOD mice. In this thesis one of the
aims was to further dissect the infiltrating T cell populations in
SOCS-1-tg mice in order to gain further insight into the mechanisms
behind disease protection. In paper I the main finding was that specific
autoreactive T cells were strongly reduced in the pancreas of SOCS-1-tg
mice compared to non-tg mice. Previous studies have shown that
autoreactive T cells are recruited to the pancreas by cytokine-induced
CXCL10 expression by the islets. The receptor for CXCL10 is CXCR3, which
was more frequently expressed on autoreactive T cells than bulk T cells.
Since SOCS-1-tg mice have reduced expression of CXCL10, autoreactive T
cells are less likely to migrate to the pancreas of these mice and pose
one possible explanation for this finding. This study shows that the
β-cell response to cytokines plays a major role in the accumulation of
autoreactive T cells to the pancreas.
Blood glucose metabolism in patients with T1D can only be restored by
islet transplantation. Unfortunately, the benefits of islet
transplantation are only short-term since the graft is lost over time.
Therefore, exposing T1D patients to the risks associated with the
immunosuppressive therapy cannot be motivated in most cases. In the
second part of this thesis the aim was to evaluate new methods to prevent
islet allograft rejection. In paper II it was shown that the mesenchymal
stromal cell (MSC)-line MBA-1 suppressed T cell proliferation in vitro
and slowed down rejection of allogeneic islets in Balb/c mice. This
indicates the possible use of MSCs as cell therapy in islet
transplantation. Another method to avoid immunosuppressive treatment is
to encapsulate the islet allografts inside immunoprotective membranes
(TheraCyteTM devices) preventing immune cells from interacting with the
grafts. In paper III it was shown that the TheraCyteTM device completely
protected islet allografts from rejection in both naive and immunized
recipient rats. This is an important finding since many patients are
sensitized prior to transplantation for example due to a previous
transplant. Finally, graft loss is difficult to study in humans and small
animal models do not always reflect the human situation. Therefore, the
final aim of this thesis was to evaluate so-called humanized mice for
their potential use to study human islet rejection mechanisms. In paper
IV human immune system (HIS) mice were established and transplanted with
human islets. However, no signs of rejection were detected in the HIS
mice questioning the usefulness of this model as a tool to study human
islet transplantation. This highlights the need for more robust humanized
mouse models
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