1,720,966 research outputs found
Glucose-6-phosphate dehydrogenase deficiency accelerates arterial aging in diabetes
Full text linkAims High glucose levels and Glucose-6-Phosphate Dehydrogenase deficiency (G6PDd) have both tissue inflammatory effects. Here we determined whether G6PDd accelerates arterial aging (information linked stiffening) in diabetes.MethodsPlasma glucose, interleukin 6 (IL6), and arterial stiffness (indexed as carotid-femoral Pulse Wave Velocity, PWV) and red blood cell G6PD activity were assessed in a large (4448) Sardinian population.ResultsAlthough high plasma glucose in diabetics, did not differ by G6DP status (178.2 +/- 55.1 vs 169.0 +/- 50.1 mg/dl) in G6DPd versus non-G6PDd subjects, respectively, IL6, and PWV (adjusted for age and glucose) were significantly increased in G6PDd vs non-G6PDd subjects (PWV, 8.0 +/- 0.4 vs 7.2 +/- 0.2 m/sec) and (IL6, 6.9 +/- 5.0 vs 4.2 +/- 3.0 pg/ml). In non-diabetics, neither fasting plasma glucose, nor IL6, nor PWV were impacted by G6PDd.ConclusionG6PDd in diabetics is associated with increased inflammatory markers and accelerated arterial aging
Longitudinal Association between Serum Uric Acid and Arterial Stiffness: Results from the Baltimore Longitudinal Study of Aging
No full textSerum uric acid (SUA) has long been associated with increased cardiovascular risk, with arterial stiffness proposed as a mediator. However, evidence on the association between SUA and arterial stiffness is limited to contradicting cross-sectional studies. In this analysis, we examined the longitudinal relationship between SUA and pulse wave velocity, a measure of arterial stiffness, in a community-dwelling population. We studied 446 women and 427 men participating in the BLSA (Baltimore Longitudinal Study of Aging), with 1409 and 1434 observations, respectively, over an average period of 6 years. At baseline, mean ages of women and men were 65±13 and 68±13 years; mean SUA, 4.6±1.1 and 5.7±1.3 mg/dL; mean pulse wave velocity, 8.1±1.7 and 8.6±1.9 m/s, respectively (P<0.0001). In gender-stratified models accounting for age, blood pressure, renal function, metabolic measures, and medications, there was a significant interaction between SUA and follow-up time in men (β=0.69; P=0.0002) but not in women. Men, but not women, in the highest gender-specific SUA tertile at baseline (SUA≥6.2 mg/dL in men and SUA≥4.9 mg/dL in women) had a greater rate of pulse wave velocity increase over time than those in the lowest tertiles (β=0.997; P=0.012). This gender difference was lost when the distribution of SUA in men and women was made comparable by excluding hyperuricemic men (SUA≥6.2 mg/dL). In conclusion, higher SUA was associated with greater increase in pulse wave velocity in men but not women; this association was lost when men with SUA≥6.2 mg/dL were not included, suggesting a threshold for SUA association with arterial stiffness, which is more frequently reached in men
Dilated hypertrophic phenotype of the carotid artery is associated with accelerated age-associated central arterial stiffening
Full text linkABSTRACT: Hypertrophic carotid geometric phenotypes (h-CGP) are predictors of incident cardiovascular disease (CVD). While arterial aging is hypothesized as a contributor to this associated risk, the association of CGPs with chronological age is not clear. In this manuscript we examine whether hypertrophic CGPs represent accelerated biological, rather than chronological, aging by examining their association with carotid-femoral pulse wave velocity (PWV), the hallmark of arterial aging. We analyzed data from 5516 participants of the SardiNIA study with a wide range of age at baseline (20–101 years), and a median follow-up time of 13 years (mean 11.5 years; maximum 17.9 years). Baseline CGPs were defined based on the common carotid lumen diameter, wall thickness, and their ratio. Subject-specific rates of change of PWV, blood pressure parameters, body mass index, glucose, and lipids were estimated using linear mixed effects models. Compared to those with typical(t-) CGP, those with dilated hypertrophy (dh-) CGP had a greater longitudinal increase in PWV; this increase was significantly greater among older individuals and men. The greater PWV longitudinal increase in dh-CGP remained significant after adjusting for baseline values and rates of change of covariates. Dilated hypertrophic CGP is independently associated with accelerated increase in age-associated arterial stiffening over time, with a strong association in men than in women. Future studies are needed to examine if this association mediates the increased risk for CVD observed in individuals with hypertrophic cardiac remodelling and the role of retarding it to reduce this risk. HIGHLIGHTS: • Individuals with dilated hypertrophic geometric phenotypes of the common carotid artery (increased age- and sex-specific wall thickness and lumen diameter) have greater future central arterial stiffening, independently of other determinants of arterial stiffening. • The dilated hypertrophic phenotype group has a greater age-specific arterial dilation, wall thickening, and stiffness (the arterial aging triad). This suggests that this phenotype is a form of accelerated aging that might explain the worse clinic outcomes observed in this group. • Understanding the natural history of the carotid geometric phenotype across the lifespan and the determinants of the deleterious progression towards the dilated hypertrophic phenotype are needed to develop interventions that reduce the adverse clinical outcomes associated with it. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11357-022-00699-w
Longitudinal trajectories of arterial stiffness and the role of blood pressure. The Baltimore longitudinal study of aging
No full textCarotid-femoral pulse wave velocity (PWV), a marker of arterial stiffness, is an established independent cardiovascular risk factor. Little information is available on the pattern and determinants of the longitudinal change in PWV with aging. Such information is crucial to elucidating mechanisms underlying arterial stiffness and the design of interventions to retard it. Between 1988 and 2013, we collected 2 to 9 serial measures of PWV in 354 men and 423 women of the Baltimore Longitudinal Study of Aging, who were 21 to 94 years of age and free of clinically significant cardiovascular disease. Rates of PWV increase accelerated with advancing age in men more than women, leading to sex differences in PWV after the age of 50 years. In both sexes, not only systolic blood pressure (SBP) â¥140 mm Hg but also SBP of 120 to 139 mm Hg was associated with steeper rates of PWV increase compared with SBP<120 mm Hg. Furthermore, there was a dose-dependent effect of SBP in men with marked acceleration in PWV rate of increase with age at SBP â¥140 mm Hg compared with SBP of 120 to 139 mm Hg. Except for waist circumference in women, no other traditional cardiovascular risk factors predicted longitudinal PWV increase. In conclusion, the steeper longitudinal increase of PWV in men than women led to the sex difference that expanded with advancing age. Age and SBP are the main longitudinal determinants of PWV, and the effect of SBP on PWV trajectories exists even in the prehypertensive range
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Lower Mitochondrial Energy Production of the Thigh Muscles in Patients With Low‐Normal Ankle‐Brachial Index
No full text
Background
Lower muscle mitochondrial energy production may contribute to impaired walking endurance in patients with peripheral arterial disease. A borderline ankle‐brachial index (ABI) of 0.91 to 1.10 is associated with poorer walking endurance compared with higher
ABI
. We hypothesized that in the absence of peripheral arterial disease, lower
ABI
is associated with lower mitochondrial energy production.
Methods and Results
We examined 363 men and women participating in the Baltimore Longitudinal Study of Aging with an
ABI
between 0.90 and 1.40. Muscle mitochondrial energy production was assessed by post‐exercise phosphocreatine recovery rate constant (
k
PC
r) measured by phosphorus magnetic resonance spectroscopy of the left thigh. A lower post‐exercise phosphocreatine recovery rate constant reflects decreased mitochondria energy production.The mean age of the participants was 71±12 years. A total of 18.4% had diabetes mellitus and 4% were current and 40% were former smokers. Compared with participants with an
ABI
of 1.11 to 1.40, those with an
ABI
of 0.90 to 1.10 had significantly lower post‐exercise phosphocreatine recovery rate constant (19.3 versus 20.8 ms
−1
,
P
=0.015). This difference remained significant after adjusting for age, sex, race, smoking status, diabetes mellitus, body mass index, and cholesterol levels (
P
=0.028). Similarly, post‐exercise phosphocreatine recovery rate constant was linearly associated with
ABI
as a continuous variable, both in the
ABI
ranges of 0.90 to 1.40 (standardized coefficient=0.15,
P
=0.003) and 1.1 to 1.4 (standardized coefficient=0.12,
P
=0.0405).
Conclusions
An
ABI
of 0.90 to 1.10 is associated with lower mitochondrial energy production compared with an
ABI
of 1.11 to 1.40. These data demonstrate adverse associations of lower
ABI
values with impaired mitochondrial activity even within the range of a clinically accepted definition of a normal
ABI
. Further study is needed to determine whether interventions in persons with
ABIs
of 0.90 to 1.10 can prevent subsequent functional decline.
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