669 research outputs found
Aortic intima media thickness in children and adolescents with type 1 diabetes : A systematic review
Aims
Greater aortic intima media thickness (aIMT), a marker of subclinical atherosclerosis, can identify individuals at risk of CVD. This systematic review with meta-analysis compared aIMT in youth with type 1 diabetes and healthy controls.
Methods
A systematic search of published literature (to July 2021) was undertaken using electronic databases MEDLINE, EMBASE, Scopus, CINAHL and AMED. Eligible studies reported aIMT in participants aged <20 years with type 1 diabetes and healthy controls. Meta-analysis was used to combine outcome data, presented as forest plots. Moderator analysis and metaregression were conducted to identify study and participant characteristics associated with aIMT. Publication bias was assessed by funnel plot inspection.
Results
Meta-analysis of nine studies (n = 1030 with type 1 diabetes and n = 498 healthy control participants) indicated, with high heterogeneity (I2 98%), that youth with type 1 diabetes have higher aIMT compared with healthy controls (mean difference [95% CIs]: 0.11 [0.04, 0.18] mm, P = 0.003). Factors associated with greater aIMT in type 1 diabetes compared to controls included: use of a phased array probe versus linear array probe; longer diabetes duration; higher insulin dose; higher BMI z score and waist circumference; higher LDL cholesterol; higher triglycerides; and higher diastolic blood pressure.
Conclusions
Type 1 diabetes in youth is associated with higher aIMT compared with healthy control individuals. Longer duration of diabetes and major CVD risk factors were also associated with higher aIMT. Together, these findings provide a strong rationale for targeting modifiable risk factors in CVD prevention. Registered in PROSPERO on 8 August 2019 (CRD42019137559)
Book Reviews
Book reviews of:
In the Wake of War: Military Occupation, Emancipation, and Civil War America. By Andrew F. Lang. (Baton Rouge: Louisiana State University Press, 2017. Acknowledgements, notes, bibliography, index. Pp. xi, 317. 29.95 paper. ISBN: 9781469640969.)
The Guerrilla Hunters: Irregular Conflicts during the Civil War. Edited by Brian D. McKnight and Marton A. Myers. (Baton Rouge: Louisiana State University Press, 2017. Acknowledgments, illustrations, maps, notes, index. Pp. ix, 399. 90 cloth, 45 hardcover. ISBN-978-0-8071-6710-6.)
In Remembrance of Emmett Till: Regional Stories and Media Responses to the Black Freedom Struggle. By Darryl Mace. (Lexington: University Press of Kentucky, 2014. Preface, introduction, illustrations, acknowledgements, notes, bibliography, index. Pp. xi, 212. 60.00. ISBN: 978- 1-58838-032-6.
Treatment of obstructive sleep apnoea leads to improved microvascular endothelial function in the systemic circulation
Background: Obstructive sleep apnoea (OSA) is a common and potentially reversible cause of systemic hypertension. The mechanisms whereby OSA leads to hypertension and the effects of treatment on arterial function, however, are not well established. Microvascular arterial endothelial and smooth muscle function was assessed in subjects with OSA before and after treatment with continuous positive airways pressure (CPAP). Methods: Ten subjects of mean (SE) age 49 (8) years with at least moderately severe OSA had detailed forearm vascular reactivity studies before and after 3 months of CPAP treatment. The systemic circulation was assessed by measuring brachial artery pressure, flow and resistance responses to intra-arterial infusions of acetylcholine (ACh; an endothelium dependent vasodilator), sodium nitroprusside (SNP; an endothelium independent vasodilator), L-NMMA (a nitric oxide (NO) antagonist), and L-arginine (the substrate for NO). Results: Before CPAP, ACh and SNP infusions increased forearm blood flow in a dose dependent manner (p,0.01). After CPAP, endothelium dependent dilation to ACh was significantly increased (434 (23)% of baseline after CPAP v 278 (20)% before CPAP, p,0.001), whereas SNP induced dilation was unchanged. Resting NO production was higher after CPAP, evidenced by a significantly greater reduction in basal flow by L-NMMA (p = 0.05). L-Arginine reversed the effect of L-NMMA in all cases. Conclusion: In patients with OSA, treatment with CPAP improves baseline endothelial NO release and stimulates endothelium dependent vasorelaxation in the systemic circulation. This is a potential mechanism for improving systemic and vascular function in patients with OSA treated with CPAP
Constraints on the non-thermal emission from Eta Carinae's blast wave of 1843
Non-thermal hard X-ray and high-energy (HE; 1 MeV < E < 100 GeV) gamma-ray
emission in the direction of Eta Carinae has been recently detected using the
INTEGRAL, AGILE and Fermi satellites. This emission has been interpreted either
in the framework of particle acceleration in the colliding wind region between
the two massive stars or in the very fast moving blast wave which originates in
the historical 1843 "Great Eruption". Archival Chandra data has been reanalysed
to search for signatures of particle acceleration in Eta Carinae's blast wave.
No shell-like structure could be detected in hard X-rays and a limit has been
placed on the non-thermal X-ray emission from the shell. The time dependence of
the target radiation field of the Homunculus is used to develop a single zone
model for the blast wave. Attempting to reconcile the X-ray limit with the HE
-ray emission using this model leads to a very hard electron injection spectrum
dN/dE ~ E^-Gamma with Gamma < 1.8, harder than the canonical value expected
from diffusive shock acceleration.Comment: 5 pages, 3 figures. Accepted for publication in A&
Birthweight and risk markers for type 2 diabetes and cardiovascular disease in childhood: the Child Heart and Health Study in England (CHASE).
AIMS/HYPOTHESIS: Lower birthweight (a marker of fetal undernutrition) is associated with higher risks of type 2 diabetes and cardiovascular disease (CVD) and could explain ethnic differences in these diseases. We examined associations between birthweight and risk markers for diabetes and CVD in UK-resident white European, South Asian and black African-Caribbean children.
METHODS: In a cross-sectional study of risk markers for diabetes and CVD in 9- to 10-year-old children of different ethnic origins, birthweight was obtained from health records and/or parental recall. Associations between birthweight and risk markers were estimated using multilevel linear regression to account for clustering in children from the same school.
RESULTS: Key data were available for 3,744 (66%) singleton study participants. In analyses adjusted for age, sex and ethnicity, birthweight was inversely associated with serum urate and positively associated with systolic BP. After additional height adjustment, lower birthweight (per 100 g) was associated with higher serum urate (0.52%; 95% CI 0.38, 0.66), fasting serum insulin (0.41%; 95% CI 0.08, 0.74), HbA1c (0.04%; 95% CI 0.00, 0.08), plasma glucose (0.06%; 95% CI 0.02, 0.10) and serum triacylglycerol (0.30%; 95% CI 0.09, 0.51) but not with BP or blood cholesterol. Birthweight was lower among children of South Asian (231 g lower; 95% CI 183, 280) and black African-Caribbean origin (81 g lower; 95% CI 30, 132). However, adjustment for birthweight had no effect on ethnic differences in risk markers.
CONCLUSIONS/INTERPRETATION: Birthweight was inversely associated with urate and with insulin and glycaemia after adjustment for current height. Lower birthweight does not appear to explain emerging ethnic difference in risk markers for diabetes
H.E.S.S. observations of gamma-ray bursts in 2003-2007
Very-high-energy (VHE; >~100 GeV) gamma-rays are expected from gamma-ray
bursts (GRBs) in some scenarios. Exploring this photon energy regime is
necessary for understanding the energetics and properties of GRBs. GRBs have
been one of the prime targets for the H.E.S.S. experiment, which makes use of
four Imaging Atmospheric Cherenkov Telescopes (IACTs) to detect VHE gamma-rays.
Dedicated observations of 32 GRB positions were made in the years 2003-2007 and
a search for VHE gamma-ray counterparts of these GRBs was made. Depending on
the visibility and observing conditions, the observations mostly start minutes
to hours after the burst and typically last two hours. Results from
observations of 22 GRB positions are presented and evidence of a VHE signal was
found neither in observations of any individual GRBs, nor from stacking data
from subsets of GRBs with higher expected VHE flux according to a
model-independent ranking scheme. Upper limits for the VHE gamma-ray flux from
the GRB positions were derived. For those GRBs with measured redshifts,
differential upper limits at the energy threshold after correcting for
absorption due to extra-galactic background light are also presented.Comment: 9 pages, 4 tables, 3 figure
Induction of humoral immune response to multiple recombinant Rhipicephalus appendiculatus antigens and their effect on tick feeding success and pathogen transmission
BACKGROUND: Rhipicephalus appendiculatus is the primary vector of Theileria parva, the etiological agent of East Coast fever (ECF), a devastating disease of cattle in sub-Saharan Africa. We hypothesized that a vaccine targeting tick proteins that are involved in attachment and feeding might affect feeding success and possibly reduce tick-borne transmission of T. parva. Here we report the evaluation of a multivalent vaccine cocktail of tick antigens for their ability to reduce R. appendiculatus feeding success and possibly reduce tick-transmission of T. parva in a natural host-tick-parasite challenge model.
METHODS: Cattle were inoculated with a multivalent antigen cocktail containing recombinant tick protective antigen subolesin as well as two additional R. appendiculatus saliva antigens: the cement protein TRP64, and three different histamine binding proteins. The cocktail also contained the T. parva sporozoite antigen p67C. The effect of vaccination on the feeding success of nymphal and adult R. appendiculatus ticks was evaluated together with the effect on transmission of T. parva using a tick challenge model.
RESULTS: To our knowledge, this is the first evaluation of the anti-tick effects of these antigens in the natural host-tick-parasite combination. In spite of evidence of strong immune responses to all of the antigens in the cocktail, vaccination with this combination of tick and parasite antigens did not appear to effect tick feeding success or reduce transmission of T. parva.
CONCLUSION: The results of this study highlight the importance of early evaluation of anti-tick vaccine candidates in biologically relevant challenge systems using the natural tick-host-parasite combination
Maternal Low-Protein Diet or Hypercholesterolemia Reduces Circulating Essential Amino Acids and Leads to Intrauterine Growth Restriction
OBJECTIVE—We have examined maternal mechanisms for adult-onset glucose intolerance, increased adiposity, and atherosclerosis using two mouse models for intrauterine growth restriction (IUGR): maternal protein restriction and hypercholesterolemia
The radio counterpart of the likely TeV binary HESS J0632+057
The few known gamma-ray binary systems are all associated with variable radio
and X-ray emission. The TeV source HESS J0632+057, apparently associated with
the Be star MWC148, is plausibly a new member of this class. Following the
identification of a variable X-ray counterpart to the TeV source we conducted
GMRT and VLA observations in June-September 2008 to search for the radio
counterpart of this object. A point-like radio source at the position of the
star is detected in both 1280 MHz GMRT and 5 GHz VLA observations, with an
average spectral index, alpha, of ~0.6. In the VLA data there is significant
flux variability on ~month timescales around the mean flux density of ~0.3 mJy.
These radio properties (and the overall spectral energy distribution) are
consistent with an interpretation of HESS J0632+057 as a lower power analogue
of the established gamma-ray binary systems.Comment: Accepted for publication in MNRAS (7 pages, 4 figures, 1 table
Conditions for the discovery of solution horizons
We present necessary and sufficient conditions for discrete infinite horizon optimization problems with unique solutions to be solvable. These problems can be equivalently viewed as the task of finding a shortest path in an infinite directed network. We provide general forward algorithms with stopping rules for their solution. The key condition required is that of weak reachability, which roughly requires that for any sequence of nodes or states, it must be possible from optimal states to reach states close in cost to states along this sequence. Moreover the costs to reach these states must converge to zero. Applications are considered in optimal search, undiscounted Markov decision processes, and deterministic infinite horizon optimization.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47927/1/10107_2005_Article_BF01581244.pd
- …