scholarly journals Effect of long-term food restriction on cardiac mechanics

1997 ◽  
Vol 273 (5) ◽  
pp. H2333-H2342 ◽  
Author(s):  
Simon Klebanov ◽  
Jeremiah T. Herlihy ◽  
Gregory L. Freeman
Keyword(s):  
Food Restriction ◽  
Relaxation Times ◽  
Cardiac Mechanics ◽  
Low Calcium ◽  
Age Related ◽  
Pressure Development ◽  
Short And Long Term ◽  
Ad Libitum ◽  
Contraction And Relaxation

Food restriction (FR) is the only known intervention capable of increasing mammalian life span. It not only increases longevity, but reduces the incidence of a broad spectrum of age-related pathologies, including cardiomyopathy, and retards the physiological decline associated with aging. Previous work from this laboratory has shown that long-term FR affects the contractile machinery of the heart, shifting the cardiac myosin profile from the fast, V1 isoform to the slow, V3 isoform. The aim of the present study was to determine whether FR also induces changes in cardiac mechanics. Isolated, isovolumically beating hearts were examined from four groups of rats: 1) ad libitum-fed rats killed at 10–13 mo of age, 2) FR rats offered only 60% of the calories consumed by ad libitum-fed rats and killed at the same age, 3) young ad libitum-fed rats having the same heart weights as the FR rats, and 4) ad libitum-fed rats subjected to short-term FR, i.e., for the last 3 wk of life, and also killed at 10–13 mo of age. Both short- and long-term FR profoundly and to approximately the same extent affected cardiac mechanics. Hearts from FR rats developed much higher pressures than hearts from the ad libitum-fed rats under conditions of low-calcium perfusate. This difference disappeared, however, when contractility was enhanced by either calcium or isoproterenol. FR prolonged both contraction and relaxation times. Long-term ad libitum-fed rats (adult, 10–13 mo of age) had a lower isoproterenol sensitivity than the young ad libitum-fed rats (10 wk of age). Both short- and long-term FR restored the sensitivity to isoproterenol. In summary, FR profoundly affects many aspects of cardiac mechanics, enhancing some age-related changes (prolongation of the contraction and relaxation times), attenuating another (increasing the isoproterenol sensitivity), and, finally, inducing some unique changes unrelated to age (increased pressure development under low-calcium perfusate).

scholarly journals Corticosterone and Glucocorticoid Receptor in the Cortex of Rats during Aging—The Effects of Long-Term Food Restriction

Nutrients ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 4526
Author(s):  
Vesna Tesic ◽  
Jelena Ciric ◽  
Irena Jovanovic Macura ◽  
Nevena Zogovic ◽  
Desanka Milanovic ◽  
...  
Keyword(s):  
Glucocorticoid Receptor ◽  
Food Restriction ◽  
Corticosterone Level ◽  
Negative Regulator ◽  
Beneficial Effects ◽  
Age Related ◽  
Old Rats ◽  
Short And Long Term ◽  
Apoptotic Effects

Numerous beneficial effects of food restriction on aging and age-related pathologies are well documented. It is also well-established that both short- and long-term food restriction regimens induce elevated circulating levels of glucocorticoids, stress-induced hormones produced by adrenal glands that can also exert deleterious effects on the brain. In the present study, we examined the effect of long-term food restriction on the glucocorticoid hormone/glucocorticoid receptor (GR) system in the cortex during aging, in 18- and 24-month-old rats. Corticosterone level was increased in the cortex of aged ad libitum-fed rats. Food restriction induced its further increase, accompanied with an increase in the level of 11β-hydroxysteroid dehydrogenase type 1. However, alterations in the level of GR phosphorylated at Ser232 were not detected in animals on food restriction, in line with unaltered CDK5 level, the decrease of Hsp90, and an increase in a negative regulator of GR function, FKBP51. Moreover, our data revealed that reduced food intake prevented age-related increase in the levels of NFκB, gfap, and bax, confirming its anti-inflammatory and anti-apoptotic effects. Along with an increase in the levels of c-fos, our study provides additional evidences that food restriction affects cortical responsiveness to glucocorticoids during aging.

Food restriction prevents age-related polyuria by vasopressin-dependent recruitment of aquaporin-2

2001 ◽  
Vol 281 (6) ◽  
pp. F1123-F1131 ◽  
Author(s):  
S. Combet ◽  
L. Teillet ◽  
G. Geelen ◽  
B. Pitrat ◽  
R. Gobin ◽  
...  
Keyword(s):  
Food Restriction ◽  
Marked Decrease ◽  
Collecting Duct ◽  
Apical Region ◽  
Principal Cells ◽  
Aquaporin 2 ◽  
Age Related ◽  
Old Rats ◽  
Ad Libitum ◽  
Chronic Food Restriction

First published August 8, 2001; 10.1152/ajprenal.00139.2001.—The mechanisms underlying the prevention of age-related polyuria by chronic food restriction were investigated in female WAG/Rij rats. The decreased osmolality of renal papilla observed in senescent rats was not corrected by food restriction. A reduced urea content in the inner medulla of senescent rats, fed ad libitum or food-restricted, was suggested by the marked decrease in expression of UT-A1 and UT-B1 urea transporters. Aquaporin-2 (AQP2) downregulation in the inner medulla of senescent rats was partially prevented by food restriction. Both AQP2 and the phosphorylated form of AQP2 (p-AQP2), the presence of which was diffuse within the cytoplasm of collecting duct principal cells in normally fed senescent rats, were preferentially targeted at the apical region of the cells in food-restricted senescent animals. Plasma vasopressin (AVP) was similar in 10- and 30-mo-old rats fed ad libitum, but was doubled in food-restricted 30-mo-old rats. This study indicates that 1) kidney aging is associated with a marked decrease in AQP2, UT-A1, and UT-B1 expression in the inner medulla and a reduced papillary osmolality; and 2) the prevention of age-related polyuria by chronic food restriction occurs through an improved recruitment of AQP2 and p-AQP2 to the apical membrane in inner medulla principal cells, permitted by increased plasma AVP concentration.

The Effects of Retesting on the Mechanical Properties of Brain Tissue

2013 ◽  
Author(s):  
A. Rezaei ◽  
M. Salimi Jazi ◽  
G. Karami ◽  
M. Ziejewski
Keyword(s):  
Mechanical Properties ◽  
Brain Tissue ◽  
Relaxation Times ◽  
Human Brain Tissue ◽  
Relaxation Functions ◽  
Before And After ◽  
Short And Long Term ◽  
Tissue Characteristics ◽  
Testing Protocols

Traumatic brain injury (TBI) is one of the most important problems in biomechanical engineering, and there have been many experiments conducted in order to characterize the mechanical properties of brain tissue. However, obtaining fresh human brain tissue is difficult, if not impossible. Also, the sample preparation and testing protocols must be carried out with great delicacy because brain tissue is very soft and vulnerable to being deformed under a very small amount of load. Most importantly, according to several researchers, each sample must be tested only one time as the tissue may be damaged and its characteristics subsequently changed. This paper is intended to examine the amount of decay that can happen in material characteristics due to retesting. A stress relaxation test is conducted on the same samples of the swine brain tissue multiple times in small and large deformations. The mechanical properties of the substance are calculated before and after retesting, and the constants of the tissue, as mechanical characteristics, are determined and compared. Short- and long-term moduli, relaxation times and relaxation functions are calculated and compared to understand how much they decay after repeating the experiments. The results show that retesting does not significantly change the elastic part of the tissue characteristics, but the viscous behavior shows a relatively sizeable change. The ability to account for the material decay of the samples due to repetition of the experiments results in the need for fewer samples and less preparation time and effort.

scholarly journals A Computational Solution to Bolster Epigenetic Clock Reliability for Clinical Trials and Longitudinal Tracking

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. 5-5
Author(s):  
Albert Higgins-Chen ◽  
Kyra Thrush ◽  
Tina Hu-Seliger ◽  
Yunzhang Wang ◽  
Sara Hagg ◽  
...  
Keyword(s):  
Clinical Trials ◽  
High Reliability ◽  
Principal Component ◽  
Epigenetic Clock ◽  
Age Related ◽  
Longitudinal Tracking ◽  
Short And Long Term ◽  
Epigenetic Biomarker ◽  
Computational Solution

Abstract Epigenetic clocks are widely used aging biomarkers, but they are calculated from methylation data for individual CpGs that can be surprisingly unreliable. We report that technical noise causes six major epigenetic clocks to deviate by 3 to 9 years between replicates. We present a novel computational solution: we perform principal component analysis followed by biological age prediction using principal components, extracting shared age-related changes across CpGs while ignoring noise from individual CpGs. Our novel principal-component versions of six clocks show agreement between most technical replicates within 1 year, and increased stability in short- and long-term longitudinal studies. This requires only one additional step compared to traditional clocks, does not require prior knowledge of CpG reliabilities, and can improve the reliability of any existing or future epigenetic biomarker. The extremely high reliability of principal component epigenetic clocks makes them particularly useful for personalized medicine and clinical trials evaluating novel aging interventions.

Working Memory Training From an Individual Differences Perspective

2019 ◽  
pp. 14-39
Author(s):  
Erika Borella ◽  
Barbara Carretti ◽  
Cesare Cornoldi ◽  
Rossana De Beni
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Task Demands ◽  
Memory Training ◽  
Training Procedure ◽  
Adaptive Procedure ◽  
Age Related ◽  
Short And Long Term ◽  
Underlying Processes

This chapter presents and discusses a verbal WM training developed for older adults. The model of working memory (WM) proposed by Cornoldi and Vecchi, which is based on an analysis of individual and age-related differences, is used as a framework for discussing the efficacy of the WM training procedure proposed and developed for older adults. The model (a) assumes that different WM tasks (and underlying processes) may be located along two continua that describe the type of content to be processed and the degree of active control required by the task and (b) considers metacognitive/motivational aspects, which also have a role in determining WM performance. The WM training procedure presented here takes into account not only the capacity to use WM resources and attentional control by adopting an adaptive procedure, but also the importance of including variations in the training task demands to produce a challenging and engaging task that sustains motivation and favor the training’s short- and long-term efficacy, at least in older adults. These aspects seem crucial in explaining the results obtained with this verbal WM training program in aging.

scholarly journals Effects of structured medium- and long-chain triacylglycerols in diets with various levels of fat on body fat accumulation in rats

2004 ◽  
Vol 91 (2) ◽  
pp. 219-225 ◽  
Author(s):  
Tatsuhiro Matsuo ◽  
Hiroyuki Takeuchi
Keyword(s):  
Body Fat ◽  
Food Restriction ◽  
Citrate Synthase ◽  
Adult Rats ◽  
Fat Accumulation ◽  
High Fat Diets ◽  
Ad Libitum ◽  
Fat Diets ◽  
Long Chain

The effects of structured medium- and long-chain triacylglycerols (MLCT) in diets containing 50–200 g fat/kg on body fat accumulation were compared with those of long-chain triacylglycerols (LCT) in rats. In rats fed ad libitum, weights of intra-abdominal adipose tissues and carcass fat contents were significantly smaller (P<0·05) in rats fed the 150–200 g MLCT/kg diet than in rats fed 150–200 g LCT/kg diet. Serum and liver triacylglycerol contents were significantly greater (P<0·05) in rats fed 200 g MLCT/kg diet, as were hepatic capacities of citrate synthase and cytochrome oxidase (P<0·05). The effects of MLCT on body fat were also examined in adult rats fed a limited amount of food (approximately 50 % of ad libitum intake). Reduction of body fat deposition during the food restriction was the same between in LCT and MLCT groups. These results suggest that accumulation of body fat was less efficient during long-term feeding of MLCT than LCT in rats fed high-fat diets ad libitum. The effect of MLCT on body fat might be influenced by the dietary fat content or by energy sufficiency.

The Effects of Retesting on the Mechanical Properties of the Brain Tissue

2013 ◽  
Author(s):  
Asghar Rezaei ◽  
Ghodrat Karami ◽  
Fardad Azarmi ◽  
Mehdi Salimi Jazi ◽  
Mariusz Ziejewski
Keyword(s):  
Mechanical Properties ◽  
Brain Tissue ◽  
Relaxation Times ◽  
Stress Relaxation Test ◽  
Preparation Time ◽  
Relaxation Functions ◽  
Before And After ◽  
Short And Long Term ◽  
The Brain

This research is intended to examine the amount of changes that can happen in material characteristics after retesting. Stress relaxation test is conducted on the same samples of the swine brain tissue for several times in small and large deformations. The mechanical properties of the substance are calculated before and after retest and the constants of the tissue, as mechanical characteristics, are determined and compared. Short- and long-term moduli, relaxation times and relaxation functions are of those data that are calculated and compared to understand how much they decay after repeating the experiments. The results show that applying different tests on one sample slightly changes the mechanical properties of the tissue and, as a result, it is partly possible to perform more than one test on the same sample resulting in less sample preparation, time and effort.

Age-related trends in short- and long-term survival after acute myocardial infarction: a 20-year population-based perspective (1975–1995)

1998 ◽  
Vol 82 (11) ◽  
pp. 1311-1317 ◽  
Author(s):  
Robert J Goldberg ◽  
Danny McCormick ◽  
Jerry H Gurwitz ◽  
Jorge Yarzebski ◽  
Darleen Lessard ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Population Based ◽  
Term Survival ◽  
Long Term Survival ◽  
Age Related ◽  
Short And Long Term

Memory

2013 ◽  
pp. 504-541 ◽  
Author(s):  
Patricia J. Bauer
Keyword(s):  
Conceptual Development ◽  
Long Term Memory ◽  
Knowledge Change ◽  
Storage And Retrieval ◽  
Age Related ◽  
Different Types ◽  
Short And Long Term ◽  
Strategic Memory ◽  
And Storage

Memory is a multidimensional construct that is evident from very early in life yet undergoes a protracted course of development. The chapter features elaboration of the construct of memory with emphasis on distinctions between short- and long-term memory and between conscious and unconscious forms of memory. It also features discussion of data on developmental changes in different types of memory, including priming, short-term and working memory, deliberate and strategic memory, and episodic and autobiographical memory. Emphasis is placed on mechanisms of age-related change, including development of the neural structures and networks subserving memory; changes in the basic mnemonic processes of encoding, consolidation and storage, and retrieval; and conceptual development and knowledge change; as well as on social influences on remembering.

Sign in / Sign up

Export Citation Format

Share Document