Background: Vitamin D status is currently diagnosed by measuring serum 25-hydroxyvitamin D 25(OH)D.Objective: This study aimed to develop a risk profile that can be used to easily identify older ...individuals at high risk of vitamin D deficiency.Design: This study was performed within the Longitudinal Aging Study Amsterdam, an ongoing cohort study in a representative sample of the Dutch older population (n = 1509 for the development sample and n = 1100 for the validation sample). Prediction models for serum 25(OH)D concentrations <50 and <30 nmol/L were developed by using backward logistic regression. Risk scores were calculated by dividing the individual regression coefficients by the regression coefficient with the lowest β to create simple scores.Results: Serum 25(OH)D concentrations <50 and <30 nmol/L were present in 46.2% and 17.5% of participants, respectively. The model for the prediction of concentrations <50 nmol/L consisted of 13 easily assessable predictors, whereas the model for concentrations <30 nmol/L contained 10 predictors. The resulting areas under the curve (AUCs) were 0.78 and 0.80, respectively. The AUC in the external validation data set was 0.71 for the <50-nmol/L model. At a cutoff of 58 in total risk score (range: 8–97), the model predicted concentrations <50 nmol/L with a sensitivity of 61% and a specificity of 82%, whereas these values were 61% and 84%, respectively, at a cutoff of 110 in the total risk score (range: 6–204) in the model for concentrations <30 nmol/L.Conclusions: Two total risk scores, including 13 or 10 predictors that can easily be assessed, were developed and are able to predict serum 25(OH)D concentrations <50 and <30 nmol/L accurately. These risk scores may be useful in clinical practice to identify persons at risk of vitamin D deficiency.
Summary
This study evaluated the yield of routine laboratory examination in a large population of older women in primary care. The prevalence of laboratory abnormalities was low and the clinical ...consequences in follow-up were limited. There was a weak association of laboratory abnormalities with osteoporosis but no association with vertebral fractures and recent fractures.
Purpose
Most osteoporosis guidelines advice routine laboratory examination. We have investigated the yield of laboratory examinations in facture risk evaluation of elderly women in primary care.
Methods
We assessed the prevalence of laboratory abnormalities and their association with risk factors for fractures, recent fractures, low bone mineral density (BMD), and prevalent vertebral fracture in 8996 women ≥ 65 years of age participating in a primary care fracture risk screening study. In a sample of 2208 of these participants, we also evaluated the medical consequences in the medical records during a follow-up period of ≥ 1 year.
Results
Vitamin D deficiency (< 30 nmol/L) was present in 13% and insufficiency (< 50 nmol/L) in 43% of the study sample. The prevalence of other laboratory abnormalities (ESR, calcium, creatinine, FT4) was 4.6% in women with risk factors for fractures, 6.1% in women with low BMD (T-score ≤ − 2.5), 6.0% after a prevalent vertebral fracture, 5.2% after a recent fracture and 2.6% in the absence of important risk factors for fractures. Laboratory abnormalities other than vitamin D were associated with low BMD (OR 1.4, 95%CI 1.1–1.8) but not with prevalent vertebral fractures nor recent fractures. Low BMD was associated with renal failure (OR 2.0, 95%CI 1.3–3.4), vitamin D insufficiency (OR 1.2, 95%CI 1.0–1.3) and deficiency (OR 1.3, 95%CI 1.1–.5). In the follow-up period, 82% of the laboratory abnormalities did not result in a new diagnosis or treatment reported in the medical records.
Conclusions
We identified a low prevalence of laboratory abnormalities in a primary care population of older women and the majority of these findings had no medical consequences.
Vitamin D status is currently diagnosed by measuring serum 25-hydroxyvitamin D 25(OH)D.
This study aimed to develop a risk profile that can be used to easily identify older individuals at high risk ...of vitamin D deficiency.
This study was performed within the Longitudinal Aging Study Amsterdam, an ongoing cohort study in a representative sample of the Dutch older population (n = 1509 for the development sample and n = 1100 for the validation sample). Prediction models for serum 25(OH)D concentrations <50 and <30 nmol/L were developed by using backward logistic regression. Risk scores were calculated by dividing the individual regression coefficients by the regression coefficient with the lowest β to create simple scores.
Serum 25(OH)D concentrations <50 and <30 nmol/L were present in 46.2% and 17.5% of participants, respectively. The model for the prediction of concentrations <50 nmol/L consisted of 13 easily assessable predictors, whereas the model for concentrations <30 nmol/L contained 10 predictors. The resulting areas under the curve (AUCs) were 0.78 and 0.80, respectively. The AUC in the external validation data set was 0.71 for the <50-nmol/L model. At a cutoff of 58 in total risk score (range: 8–97), the model predicted concentrations <50 nmol/L with a sensitivity of 61% and a specificity of 82%, whereas these values were 61% and 84%, respectively, at a cutoff of 110 in the total risk score (range: 6–204) in the model for concentrations <30 nmol/L.
Two total risk scores, including 13 or 10 predictors that can easily be assessed, were developed and are able to predict serum 25(OH)D concentrations <50 and <30 nmol/L accurately. These risk scores may be useful in clinical practice to identify persons at risk of vitamin D deficiency.
To determine the roles of nitric oxide, endothelin-1 and phosphatidylinositol 3-kinase (PI3-kinase) in acute responses of isolated rat skeletal muscle arterioles to insulin.
Rat cremaster first order ...arterioles were separated from surrounding tissue, cannulated in a pressure myograph and responses to insulin (4 microU/ml-3.4 mU/ml) were studied without intraluminal blood or flow.
Insulin alone did not significantly affect arteriolar diameter. Non-selective antagonism of endothelin receptors, with PD-142893, uncovered insulin-induced vasodilatation (25+/-8% from baseline at 3.4 mU/ml), which was abolished by inhibition of NO synthesis with N(G)-nitro-L-arginine (L-NA). Inhibition of NO synthesis alone uncovered insulin-induced vasoconstriction at physiological concentrations (21+/-5% from baseline diameter at 34 microU/ml), which was abolished by PD-142893. The NO donor, S-nitroso-N-acetyl-penicillamine (SNAP) inhibited insulin-induced vasoconstriction during NOS inhibition, even at a concentration that did not elicit vasodilatation itself. Inhibition of PI3-kinase, an intracellular mediator of insulin-induced NO production, with wortmannin, also uncovered insulin-induced vasoconstriction (13+/-3% from baseline at 34 microU/ml) that was abolished by PD-142893.
Insulin induces both nitric oxide and endothelin-1 activity in rat cremaster first-order arterioles. This study demonstrates for the first time that vasoconstrictive effects of physiological concentrations of insulin during inhibition of NOS activity are mediated by endothelin and that insulin induces endothelin-1-mediated vasoconstriction in isolated skeletal muscle arterioles during inhibition of PI3-kinase. These findings support the hypothesis of altered microvascular reactivity to insulin in conditions of diminished PI3-kinase activity, a prominent feature of insulin resistance.
The objective of the current study was to combine a time‐encoded pseudocontinuous arterial spin labeling (te‐pCASL) scheme with a golden angle radial readout for simultaneous acquisition of ...angiography and perfusion images from one single dataset, both in a highly flexible single‐slice approach as well as within a multislice setting. A te‐pCASL preparation and the golden angle radial readout were both used as a temporal resolution tool to retrospectively choose the temporal window for the reconstruction of both angiography and perfusion images from a single‐slice dataset. The temporal window could be chosen retrospectively and adjusted to the hemodynamics of the volunteer on the scanner for the single‐slice dataset. Angiographic images were reconstructed at a minimum temporal resolution of 69 ms. For the perfusion phase, only the densely sampled center of k‐space was included in the reconstruction. For a multislice acquisition, the golden angle radial readout allowed reconstruction of images with different spatial resolutions to provide angiographic and perfusion information over 10 slices. The te‐pCASL preparation was used as the only source for dynamic information. The multislice acquisition shows the ability of the golden angle radial readout to display the inflow of the labeled blood into the arteries as well as the perfusion in the tissue with full brain coverage. By combining a te‐pCASL preparation with a golden angle radial readout, single‐slice high temporal resolution angiography and good quality perfusion images were reconstructed in a flexible manner from a single dataset. Optimizing the golden angle radial readout for reconstructions at multiple spatial resolutions allows for multislice acquisition.
A time‐encoded pseudocontinuous arterial spin labeling scheme was combined with a golden angle radial readout for simultaneous acquisition of angiography and perfusion images from one single dataset. This allows for retrospectively changing the temporal window, because the golden angle readout was optimized as a temporal resolution tool. Optimizing this readout for different spatial resolutions shows the ability to display the inflow of labeled blood into the arteries as well as the perfusion in the tissue with full brain coverage.
Background
Atherosclerosis is a chronic inflammatory disease of large‐ to medium‐sized arteries and is the main underlying cause of death worldwide. The lymphatic vasculature is critical for ...processes that are intimately linked to atherogenesis such as the immune response and cholesterol metabolism. However, whether lymphatic vessels truly contribute to the pathogenesis of atherosclerosis is less clear despite increasing research efforts in this field.
Design
PubMed and Ovid MEDLINE databases were searched. In addition, key review articles were screened for relevant original publications.
Results
Current knowledge about lymphatic vessels in the arterial wall came from studies that examined the presence and location of such vessels in human atherosclerotic plaque specimens, as well as in a variety of arteries in animal models for atherosclerosis (e.g. rabbits, dogs, rats and mice). Generally, three experimental approaches have been used to investigate the functional role of plaque‐associated lymphatic vessels; experimental lymphostasis was used to investigate lymphatic drainage of the arterial wall, and more recently, studies with genetic interventions and/or surgical transplantation have been performed.
Conclusions
Lymphatic vessels seem to be mostly present in the adventitial layer of the arterial walls of animals and humans. They are involved in reverse cholesterol transport from atherosclerotic lesions, and arteries with a dense lymphatic network seem naturally protected against atherosclerosis. Lymphangiogenesis is a process that is an important part of the inflammatory loop in atherosclerosis. However, how augmenting or impeding the distribution of lymphatic vessels impacts disease progression remains to be investigated in future studies.
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