3,134 publications from this institution
This study documents a significant increase of a blunted nocturnal BP decline in patients with MS. Patients with MS were also characterized by elevated values of relevant markers of cardiovascular risk, including fibrinogen and globular sedimentation rate.
Abstract —The approach of establishing a time-specified tolerance limit reflecting the circadian variability in blood pressure and then determining the hyperbaric index, the area of blood pressure excess above the upper limit of the tolerance interval, has been proposed for diagnosing hypertension as well as for evaluating the patient’s response to treatment. The retrospective evaluation of this test provided high sensitivity and specificity in the diagnosis of hypertension, with a threshold value for the hyperbaric index of 15 mm Hg · h. To evaluate the stability and reproducibility of this tolerance-hyperbaric test, we studied 332 previously untreated subjects (218 men) who underwent sequential 48-hour ambulatory blood pressure monitoring for 2 years, providing a total of 1337 blood pressure profiles. Diagnosis of hypertension was established for each subject on the restricted basis of presenting at least 1 blood pressure profile with a hyperbaric index above the previously defined threshold. Sensitivity of this tolerance-hyperbaric test was 98.6%, with a negative predictive value of 99.7%. For the same subjects, the blood pressure load (percentage of values >140/110/90 mm Hg for systolic/mean arterial/diastolic blood pressure during activity or >120/95/80 mm Hg during resting hours) had a sensitivity of 49% and specificity of 25%. The 24-hour mean, still the most common approach for diagnosing hypertension on the basis of ambulatory monitoring, had sensitivities of 40% and 31% for systolic and diastolic blood pressure, respectively. Despite the limitations of ambulatory blood pressure monitoring, the tolerance-hyperbaric test represents a reproducible, noninvasive, and high-sensitivity test for the identification of subjects in need of prophylactic or therapeutic intervention.
The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick oriented PP) into the food stimulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.
Abstract The relationship between the structural properties of selected dietary flavanoids and flavonoids and their affinities for HSA were investigated by fluorescence analysis. The binding process with HSA was strongly influenced by the structural differences of the compounds under study. Methylation of hydroxyl groups improved the affinities for HSA by 2–16‐fold. Hydroxylation on rings A, B, and C also affected the affinity for HSA significantly. Glycosylation decreased the affinities for HSA by 1–3 orders of magnitude depending on the conjugation site and the class of sugar moiety. Hydrogenation of the C2=C3 double bond also decreased the binding affinity. Galloylated catechins and pyrogallol‐type catechins exhibited higher binding affinities for HSA than non‐galloylated and catechol‐type catechins, respectively. The affinities for HSA increased with increasing partition coefficients and decreased with increasing hydrogen bond donor and acceptor numbers of flava(o)noids, which suggested that the binding interaction was mainly caused by hydrophobic forces.
Some studies based on ambulatory blood pressure (BP) monitoring (ABPM) have reported a reduction in sleep-time relative BP decline towards a more non-dipping pattern in the elderly, but rarely have past studies included a proper comparison with younger subjects, and no previous report has evaluated the potential role of hypertension treatment time on nighttime BP regulation in the elderly. Accordingly, we evaluated the influence of age and time-of-day of hypertension treatment on the circadian BP pattern assessed by 48-h ABPM. This cross-sectional study involved 6147 hypertensive patients (3108 men/3039 women), 54.0 ± 13.7 (mean ± SD) yrs of age, with 2137 (978 men/1159 women) being ≥60 yrs of age. At the time of study, 1809 patients were newly diagnosed and untreated, and 4338 were treated with hypertension medications. Among the later, 2641 ingested all their prescribed BP-lowering medications upon awakening, whereas 1697 ingested the full daily dose of ≥1 hypertension medications at bedtime. Diagnosis of hypertension in untreated patients was based on ABPM criteria, specifically an awake systolic (SBP)/diastolic (DBP) BP mean ≥135/85 mm Hg and/or an asleep SBP/DBP mean ≥120/70 mm Hg. Collectively, older in comparison with younger patients were more likely to have diagnoses of microalbuminuria, chronic kidney disease, obstructive sleep apnea, metabolic syndrome, anemia, and/or obesity. In addition, the group of older vs. younger patients had higher glucose, creatinine, uric acid, triglycerides, and fibrinogen, but lower cholesterol, hemoglobin, and estimated glomerular filtration rate. In older compared with younger patients, ambulatory SBP was significantly higher and DBP significantly lower (p < .001), mainly during the hours of nighttime sleep and initial hours after morning awakening. The prevalence of non-dipping was significantly higher in older than younger patients (63.1% vs. 41.1%; p < .001). The largest difference between the age groups was in the prevalence of a riser BP pattern, i.e., asleep SBP mean greater than awake SBP mean (19.9% vs. 4.9% in older vs. younger patients, respectively; p < .001). The sleep-time relative SBP decline was mainly unchanged until ~40 yrs of age, and then significantly and progressively decreasing with increasing age at a rate of .28%/yr (p < .001), reaching a minimum value of 4.38% ± .47% for patients ≥75 yrs of age. Treated compared with untreated patients showed lower awake and asleep SBP means, although the predictable changes of SBP and DBP with age were equivalent in both groups. As a consequence, there were no significant differences between untreated and treated patients in the changes of the sleep-time relative SBP and DBP declines with age. Additionally, the asleep SBP and DBP means were significantly lower and the sleep-time relative SBP and DBP declines significantly higher at all ages in patients ingesting ≥1 BP-lowering medications at bedtime as compared with those ingesting all medications upon awakening. Our findings document a significantly elevated prevalence of a blunted nighttime BP decline with increasing age ≥40 yrs. The prevalence of a riser BP pattern, associated with highest cardiovascular risk among all possible BP patterns, was 4 times more prevalent in patients ≥60 yrs of age than those <60 yr of age. Most important, there was an attenuated prevalence of a blunted nighttime BP decline at all ages when ≥1 hypertension medications were ingested at bedtime as compared with when all of them were ingested upon awakening. These findings indicate that older age should be included among the conditions for which ABPM is recommended for proper cardiovascular risk assessment.
Abstract We investigate the impact of antagonistic pleiotropy on the most widely used methods of estimation of the average coefficient of dominance of deleterious mutations from segregating populations. A proportion of the deleterious mutations affecting a given studied fitness component are assumed to have an advantageous effect on another one, generating overdominance on global fitness. Using diffusion approximations and transition matrix methods, we obtain the distribution of gene frequencies for nonpleiotropic and pleiotropic mutations in populations at the mutation-selection-drift balance. From these distributions we build homozygous and heterozygous chromosomes and assess the behavior of the estimators of dominance. A very small number of deleterious mutations with antagonistic pleiotropy produces substantial increases on the estimate of the average degree of dominance of mutations affecting the fitness component under study. For example, estimates are increased three- to fivefold when 2% of segregating loci are overdominant for fitness. In contrast, strengthening pleiotropy, where pleiotropic effects are assumed to be also deleterious, has little effect on the estimates of the average degree of dominance, supporting previous results. The antagonistic pleiotropy model considered, applied under mutational parameters described in the literature, produces patterns for the distribution of chromosomal viabilities, levels of genetic variance, and homozygous mutation load generally consistent with those observed empirically for viability in Drosophila melanogaster.
