Eicosapentaenoic acid incorporation in membrane phospholipids modulates receptor-mediated phospholipase C and membrane fluidity in rat ventricular myocytes in culture

The influence of increased incorporation of linoleic acid (18:2n-6) and eicosapentaenoic acid (20:5n-3) in membrane phospholipids on receptor-mediated phospholipase Cβ (PLC-β) activity in cultured rat ventricular myocytes was investigated. For this purpose, cells were grown for 4 days in control, stearic acid (18:0)/oleic acid (18:1n-9), 18:2n-6 and 20:5n-3 enriched media, and subsequently assayed for the basal- and phenylephrine- or endothelin-1-induced total inositol phosphate formation. The various fatty acid treatments resulted in the expected alterations of fatty acid composition of membrane phospholipids. In 18:2n-6-treated cells, the incorporation of this 18:2n-6 in the phospholipids increased from 17.1 mol % in control cells to 38.9 mol %. In 20:5n-3-treated cells, incorporation of 20: 5n-3 and docosapentaenoic acid (22:5n-3) in the phospholipids increased from 0.5 and 2.7 mol % in control cells to 23.2 and 9.7 mol %, respectively. When 20:5n-3-treated cells were stimulated with phenylephrine or endothelin-1, the inositolphosphate production decreased by 33.2% and increased by 43.4%, respectively, as compared to cells grown in control medium. No efffects were seen in 18:2n-6-treated cells. When 18:0/18:1n-9-treated cells were stimulated with endothelin-1, inositolphosphate formation increased by 26.4%, whereas phenylephrine-stimulated inositolphosphate formation was not affected. In saponin-permeabilized cells, that were pre-treated with 20:5n-3, the formation of total inositolphosphates after stimulation with GTPγS, in the presence of Ca2+, was inhibited 19.3%. This suggests that the 20:5n-3 effect on intact cardiomyocytes could be exerted either on the level of agonist-receptor, receptor-GTP-binding-protein coupling or GTP-binding-protein-PLC-β interaction. Investigation of the time course of saponin-induced permeabilization of the cardiomyocytes, measured by the release of lactate dehydrogenase, unmasked a slight decrease in the rate of permeabilization by 20:5n-3 pretreatment, indicating a protective effect. This led the authors to measure the cholesterol/phospholipid molar ratio, the double bond index of membrane phospholipids, and the membrane fluidity; the latter by using a diphenylhexatriene probe. In 20: 5n-3-pretreated cells, a strong increase in the cholesterol/phospholipid molar ratio (from 0.23 to 0.39), a marked increase in the double bond index (from 1.76 to 2.33), and a slight decrease in fluidity (steady-state anisotropy r(ss) of the diphenylhexatriene probe increased from 0.196 to 0.217) were observed. Thus, treatment of cardiomyocytes for 4 days with 20:5n-3, but not with 18:2n-6, causes alterations of receptor-mediated phospholipase Cβ activity. A causal relationship may exist between the 20:5 n-3-induced alterations of the physicochemical properties in the bilayer and of the agonist-stimulated phosphatidylinositol cycle activity

High-affinity prorenin binding to cardiac man-6-P/IGF-II receptors precedes proteolytic activation to renin

Mannose-6-phosphate (man-6-P)/insulin-like growth factor-II (man-6-P/IgF-II) receptors are involved in the activation of recombinant human prorenin by cardiomyocytes. To investigate the kinetics of this process, the nature of activation, the existence of other prorenin receptors, and binding of native prorenin, neonatal rat cardiomyocytes were incubated with recombinant, renal, or amniotic fluid prorenin with or without man-6-P. Intact and activated prorenin were measured in cell lysates with prosegment- and renin-specific antibodies, respectively. The dissociation constant (K(d)) and maximum number of binding sites (B(max)) for prorenin binding to man-6-P/IGF-II receptors were 0.6 +/- 0.1 nM and 3,840 +/- 510 receptors/myocyte, respectively. The capacity for prorenin internalization was greater than 10 times B(max). Levels of internalized intact prorenin decreased rapidly (half-life = 5 +/- 3 min) indicating proteolytic prosegment removal. Prorenin subdivision into man-6-P-free and man-6-P-containing fractions revealed that only the latter was bound. Cells also bound and activated renal but not amniotic fluid prorenin. We concluded that cardiomyocytes display high-affinity binding of renal but not extrarenal prorenin exclusively via man-6-P/IGF-II receptors. Binding precedes internalization and proteolytic activation to renin thereby supporting the concept of cardiac angiotensin formation by renal prorenin

Physical Activity and Sedentary Behavior From Discharge to 1 Year After Inpatient Rehabilitation in Ambulatory People With Spinal Cord Injury:A Longitudinal Cohort Study

Objective: To evaluate changes in duration of physical activity (PA) and sedentary behavior (SB) from discharge to 1 year after inpatient rehabilitation in ambulatory people with spinal cord injury (SCI). Design: Longitudinal cohort study with objective measurements of physical behavior at discharge and at 6 and 12 months post discharge. Setting: Three rehabilitation centers and the participant's home environment. Participants: Participants (N= 47) with ambulatory function were consecutively recruited from the self-management and self-efficacy in patients with SCI cohort (age 18 years or older, recent SCI, expected inpatient stay >4wk). Mean age was 54.5 +/- 12.9 years, all had incomplete lesions, 53% were men, 49% had tetraplegia, and 51% were community ambulators at discharge. Interventions: Not applicable. Main Outcome Measures: Duration (min) of PA (summed duration of walking, cycling, running, and wheeling) and SB (sitting/lying). Results: Mean duration of PA increased by 21 min/d (95% confidence interval, 7-35) and SB decreased by 64 min/d (95% confidence interval, -94 to -35) from discharge to 6 months after inpatient rehabilitation. No changes were found in the second half-year. One year after discharge mean PA was 116 +/- 59 min/d and mean SB was 665 +/- 121 min/d. The increase in PA was the result of an almost doubling of time spent walking. Variability in physical behavior and its change was large. Older age and lower ambulation level were associated with lower PA, lower ambulation level with higher SB, and tetraplegia was associated with a reduced increase in PA. Conclusions: At group level, duration of PA and SB improved following inpatient rehabilitation in ambulatory people with SCI. However, there were large differences between individuals. Levels 1 year after discharge were still unfavorable, particularly regarding SB. (C) 2020 by the American Congress of Rehabilitation Medicin

The Influence of Overweight/Obesity on Patient-Perceived Physical Functioning and Health-Related Quality of Life After Primary Total Hip Arthroplasty

# The Author(s) 2011. This article is published with open access at Springerlink.com Background Overweight/obesity in patients after total hip arthroplasty (THA) is a growing problem and is associated with postoperative complications and a negative effect on functional outcome. The objective of this study is to determine to what extent overweight/obesity is associated with physical functioning and health-related quality of life 1 year after primary THA

Accuracy of self-reported body weight, height and waist circumference in a Dutch overweight working population

<p>Abstract</p> <p>Background</p> <p>In population studies, body mass index (BMI) is generally calculated from self-reported body weight and height. The self-report of these anthropometrics is known to be biased, resulting in a misclassification of BMI status. The aim of our study is to evaluate the accuracy of self-reported weight, height and waist circumference among a Dutch overweight (Body Mass Index [BMI] ≥ 25 kg/m²) working population, and to determine to what extent the accuracy was moderated by sex, age, BMI, socio-economic status (SES) and health-related factors.</p> <p>Methods</p> <p>Both measured and self-reported body weight and body height were collected in 1298 healthy overweight employees (66.6% male; mean age 43.9 ± 8.6 years; mean BMI 29.5 ± 3.4 kg/m²), taking part in the ALIFE@Work project. Measured and self-reported waist circumferences (WC) were available for a sub-group of 250 overweight subjects (70.4% male; mean age 44.1 ± 9.2 years; mean BMI 29.6 ± 3.0 kg/m²). Intra Class Correlation (ICC), Cohen's kappa and Bland Altman plots were used for reliability analyses, while linear regression analyses were performed to assess the factors that were (independently) associated with the reliability.</p> <p>Results</p> <p>Body weight was significantly (p < 0.001) under-reported on average by 1.4 kg and height significantly (p < 0.001) over-reported by 0.7 cm. Consequently, BMI was significantly (p < 0.001) under-reported by 0.7 kg/m². WC was significantly (p < 0.001) over-reported by 1.1 cm. Although the self-reporting of anthropometrics was biased, ICC's showed high concordance between measured and self-reported values. Also, substantial agreement existed between the prevalences of BMI status and increased WC based on measured and self-reported data. The under-reporting of BMI and body weight was significantly (p < 0.05) affected by measured weight, height, SES and smoking status, and the over-reporting of WC by age, sex and measured WC.</p> <p>Conclusion</p> <p>Results suggest that self-reported BMI and WC are satisfactorily accurate for the assessment of the prevalence of overweight/obesity and increased WC in a middle-aged overweight working population. As the accuracy of self-reported anthropometrics is affected by measured weight, height, WC, smoking status and/or SES, results for these subgroups should be interpreted with caution. Due to the large power of our study, the clinical significance of our statistical significant findings may be limited.</p> <p>Trial Registration</p> <p>ISRCTN04265725</p

The Real Price Of Parking Policy

This paper is the first to empirically examine the residents' willingness to pay for on-street parking permits as well as the cost of cruising using an identification methodology based on house prices for Amsterdam. The average cost of cruising is €1.30 per day. The average residents' willingness to pay for a parking permit is €8 per day. Further, we show that the introduction of paid parking in a neighborhood decreases house prices in this neighbourhood. This discussion paper has resulted in a publication in the Journal of Urban Economics .on-street parking, cruising, parking policy, parking permits

The real price of parking policy

This paper is the first to empirically examine the residents' willingness to pay for on-street parking permits as well as the cost of cruising using an identification methodology based on house prices for Amsterdam. The residents' cost of cruising is about [euro]1 per day. The residents' willingness to pay for a parking permit is about [euro]10 per day.Street parking Cruising House prices Parking policy Parking permits Residential parking