Is there a relationship between the total volume of load lifted in bench press exercise and the rating of perceived exertion?

Aim. The purpose of the study was to investigate the relationship between the total volume of load lifted (TVLL) and the rating of perceived exertion (RPE) measures during different resistance training (RT) schemes using the bench press exercise. Methods. The present study was divided into two experiments. In the first experiment, 18 healthy men performed three different RT schemes: a strength oriented scheme (SS), a muscular endurance oriented scheme (ES) and a hypertrophy oriented scheme (HS). TVLL was calculated for each scheme. Mean-RPE and session-RPE were assessed. In the second experiment, 23 men performed two resistance exercise bouts at different intensities (50 %-1RM and 75%-1RM) with matched TVLL. Mean-RPE and session-RPE were also assessed. Results. SS and HS showed higher TVLL and greater RPE scores as compared to ES (P<0.05). No significant difference was observed between SS and HS. It was verified significant positive correlations between TVLL and session-RPE (SS r=0.63, HS r=0.64, ES r=0.56; P<0.05), and between mean-RPE and TVLL (SS r=0.55, HS r=0.52, ES r=0.47; P<0.05) for all schemes. No differences were observed for mean-RPE, session-RPE and TVLL between the 50%-1RM and 75%1RM. Significant positive relationships between TVLL and session-RPE (50 %-1RM r=0.61, 75 %-1RM r=0.66; p<0.05) and between TVLL and mean-RPE (50 %-1RM r=0.51, 75%1RM r=0.49; P<0.05) were observed. Conclusion. The results of this study have shown that the TVLL in RT influences RPE measures. These findings corroborates the existence of a relationship between total work performed (external training load) and perception of effort (internal training load).

Age-dependent changes in rat lacrimal gland anti-oxidant and vesicular related protein expression profiles

Purpose: Anti-oxidation and exocytosis are important for maintaining exocrine tissue homeostasis. During aging, functional and structural alterations occur in the lacrimal gland (LG), including oxidative damage to proteins, lipids, and DNA. The aims of the present study were to determine in the aging LG: a) the effects of aging on LG structure and secretory activity and b) changes in the expression of oxidative stress markers. Methods: To address these goals, tear secretion composition and corneal impression cytology were compared between male Wistar rats of 2 (control) and 24 (aged) months. LG morphology and the expression levels of vitamin E and malonaldehyde (MDA) were evaluated to determine the anti-oxidant activity and lipid peroxidation, respectively. RT-PCR and western blot analysis were used for the analysis of Ras related in brain GTPase protein (Rab) and soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins of the secretory machinery (i.e.; Rab 3d, Rab 27, vesicle-associated membrane protein-2 (Vamp-2), and syntaxin). Results: Histological analysis of aged rats revealed a higher frequency of corneal epithelia metaplasia. In the acinar cells, organelles underwent degeneration, and lipofucsin-like material accumulated in the cytoplasm along with declines in the anti-oxidant marker vitamin E. Rab3d and Rab27b mRNA levels fell along with Rab3d protein expression, whereas syntaxin levels increased. Conclusions: These findings indicate that exocytotic and anti-oxidant mechanisms become impaired with age in the rat LG. In parallel with these structural alterations, functional declines may contribute to the pathophysiology caused by tear film modification in dry eye disease.

Topographic and age-dependent distribution of subchondral bone density in the elbow joints of clinically normal dogs

OBJECTIVE: To investigate topographic and age-dependent adaptation of subchondral bone density in the elbow joints of healthy dogs by means of computed tomographic osteoabsorptiometry (CTOAM). Animals-42 elbow joints of 29 clinically normal dogs of various breeds and ages. PROCEDURES: Subchondral bone densities of the humeral, radial, and ulnar joint surfaces of the elbow relative to a water-hydroxyapatite phantom were assessed by means of CTOAM. Distribution patterns in juvenile, adult, and geriatric dogs (age, < 1 year, 1 to 8 years, and > 8 years, respectively) were determined and compared within and among groups. RESULTS: An area of increased subchondral bone density was detected in the humerus distomedially and cranially on the trochlea and in the olecranon fossa. The ulna had maximum bone densities on the anconeal and medial coronoid processes. Increased bone density was detected in the craniomedial region of the joint surface of the radius. A significant age-dependent increase in subchondral bone density was revealed in elbow joint surfaces of the radius, ulna, and humerus. Mean subchondral bone density of the radius was significantly less than that of the ulna in paired comparisons for all dogs combined and in adult and geriatric, but not juvenile, dog groups. CONCLUSIONS AND CLINICAL RELEVANCE: An age-dependent increase in subchondral bone density at the elbow joint was revealed. Maximal relative subchondral bone densities were detected consistently at the medial coronoid process and central aspect of the humeral trochlea, regions that are commonly affected in dogs with elbow dysplasia.

Angiopoietin-2 deficiency decelerates age-dependent vascular changes in the mouse retina

Retinae of aged humans show signs of vascular regression. Vascular regression involves a mismatch between Angiopoietin-2 (Ang-2) and vascular endothelial growth factor (VEGF) expression. We used heterozygous Ang-2 deficient (Ang2LacZ) mice to evaluate murine retinal vascular changes and gene expression of growth factors. Vascular changes were assessed by quantitative retinal morphometry and gene expression levels of growth factors were measured by quantitative PCR. The numbers of endothelial cells and pericytes did not change in the Ang2LacZ retinae with age, whereas they decreased throughout the age spectrum studied in the wild type retinae. Moreover, vascular regression significantly decelerated in the heterozygous Ang2LacZ retinae (200% to 1 month), while the formation of acellular capillaries was significantly increased at 13 months in the wild type retinae (340% to 1 month). Gene expression analysis revealed that VEGF, Ang-1, PDGF-B and Ang2 mRNA levels were decreased in the wild type retinae at 9 month of age. However, the decrease of Ang-2 was smaller compared with other genes. While VEGF levels dropped in wild type mice up to 60% compared to 1 month, VEGF increased in heterozygous Ang-2 deficient retinae at an age of 9 months (141% to 1 month). Similarly, Ang-1 levels decreased in wild type mice (45% to 1 month), but remained stable in Ang2LacZ mice. These data suggest that Ang-2 gene dose reduction decelerates vasoregression in the retina with age. This effect links to higher levels of survival factors such as VEGF and Ang-1, suggesting that the ratio of these factors is critical for capillary cell survival.

Age-dependent differences in demographics, risk factors, co-morbidity, etiology, management, and clinical outcome of acute ischemic stroke

BACKGROUND : Comparisons between younger and older stroke patients including comorbidities are limited. METHODS : Prospective data of consecutive patients with first ever acute ischemic stroke were compared between younger ( 45 years). RESULTS : Among 1004 patients, 137 (14 %) were

Impaired endothelial progenitor cell function predicts age-dependent carotid intimal thickening

OBJECTIVES: We investigated whether qualitative or quantitative alterations of the endothelial progenitor cell (EPC) pool predict age-related structural vessel wall changes. BACKGROUND: We have previously shown that age-related endothelial dysfunction is accompanied by qualitative rather than quantitative changes of EPCs. Animal studies suggest that impaired EPC functions lead to accelerated arterial intimal thickening. METHODS: Intima-media thickness (IMT) was measured in the common carotid artery in our previously published groups of younger (25 +/- 1 years, n = 20) and older (61 +/- 2 years, n = 20) healthy non-smoking volunteers without arterial hypertension, hypercholesterolemia, and diabetes mellitus. Endothelial progenitor cells (EPCs, KDR(+)/CD34(+) and KDR(+)/CD133(+)) were counted in peripheral blood using flow cytometry. In ex vivo expanded EPCs, the function was determined as chemotaxis to VEGF, proliferation, and survival. RESULTS: We observed thicker IMT in older as compared to younger subjects (0.68 +/- 0.03 mm Vs. 0.48 +/- 0.02 mm, P < 0.001). Importantly, there were significant inverse univariate correlations between IMT, EPC chemotaxis, and survival (r = -0.466 P < 0.05; r = -0.463, P < 0.01). No correlation was observed with numbers of circulating EPCs. Multivariate regression analysis revealed that age, mean arterial pressure and migration of EPCs were independent predictors of IMT (R (2 )= 0.58). CONCLUSION: Impaired EPC function may lead to accelerated vascular remodeling due to chronic impairment of endothelial maintenance.

Age-dependent decrease in 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) activity in hypertensive patients

BACKGROUND: The prevalence of arterial hypertension lacking a defined underlying cause increases with age. Age-related arterial hypertension is insufficiently understood, yet known characteristics suggest an aldosterone-independent activation of the mineralocorticoid receptor. Therefore, we hypothesized that 11beta-HSD2 activity is age-dependently impaired, resulting in a compromised intracellular inactivation of cortisol (F) with F-mediated mineralocorticoid hypertension. METHODS: Steroid hormone metabolites in 24-h urine samples of 165 consecutive hypertensive patients were analyzed for F and cortisone (E), and their TH-metabolites tetrahydro-F (THF), 5alphaTHF, TH-deoxycortisol (THS), and THE by gas chromatography-mass spectroscopy. Apparent 11beta-HSD2 and 11beta-hydroxylase activity and excretion of F metabolites were assessed. RESULTS: In 72 female and 93 male patients aged 18-84 years, age correlated positively with the ratios of (THF + 5alphaTHF)/THE (P = 0.065) and F/E (P < 0.002) suggesting an age-dependent reduction in the apparent 11beta-HSD2 activity, which persisted (F/E; P = 0.020) after excluding impaired renal function. Excretion of F metabolites remained age-independent most likely as a consequence of an age-dependent diminished apparent 11beta-hydroxylase activity (P = 0.038). CONCLUSION: Reduced 11beta-HSD2 activity emerges as a previously unrecognized risk factor contributing to the rising prevalence of arterial hypertension in elderly. This opens new perspectives for targeted treatment of age-related hypertension.

Age-dependent suppression of SERCA2a mRNA in pediatric atrial myocardium

Differential expression of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban (PLB) has been shown in heart failure and atrial arrhythmias. We investigated the influence of volume overload and age on their expression in pediatric atrial myocardium. Right atrial specimens from 18 children with volume overloaded right atrium (VO) and 12 patients without overload were studied. Each group was further divided into patients less than and older than 12 months of age. Only in the younger patients SERCA2a was significantly reduced in the VO group. In younger patients PLB mRNA level tended to be lower in VO. The PLB:SERCA protein ratio was significantly reduced in the VO group. Age itself did not influence the SERCA2a and PLB expression, if the hemodynamic overload was not taken into account. This study is the first to show a combined influence of volume overload and age on atrial SERCA2a expression.

From diarrhea to obesity in prohormone convertase 1/3 deficiency: age-dependent clinical, pathologic, and enteroendocrine characteristics

GOALS The aim of this report is to delineate the clinical, pathologic, and enteroendocrine (EE) features of prohormone convertase 1/3 (PC1/3) deficiency in children. BACKGROUND Prohormone convertases play a pivotal role in the activation of biologically inactive hormones. Congenital defects in the EE axis, such as PC1/3 deficiency, have been rarely reported and their pathophysiological mechanisms are largely unknown. STUDY EE function and pathology was evaluated in 4 males (1, 2, 7, and 10 y old) from 2 families with PC1/3 deficiency at a university children's hospital. Clinical course, pathology analysis including immunohistochemistry for PC1/3, PC2, and glucagon-like peptide 1 (GLP-1) and electron microscopy, as well as EE function tests (GLP-1, GLP-2, oral glucose tolerance test) were performed. RESULTS All (n=4) suffered from congenital severe diarrhea associated with malabsorption. The diarrhea improved during the first year of life and hyperphagia with excessive weight gain (BMI>97th percentile) became the predominant phenotype at an older age. Analysis of the enteroendocrine axis revealed high proinsulin levels (57 to 1116 pmol/L) in all patients, low serum GLP-2 levels, and impaired insulin and GLP-1 secretion after an oral glucose tolerance test at a young age, with improvement in 1 older child tested. Electron microscopy showed normal ultrastructure of enterocytes and EE cells. Immunohistochemistry revealed normal expression of chromogranin A, a marker of EE cells but markedly reduced immunostaining for PC1/3 and PC2 in all patients. CONCLUSIONS PC1/3 deficiency is associated with an age dependent, variable clinical phenotype caused by severe abnormalities in intestinal and EE functions. Serum level of proinsulin can be used as an effective screening tool.

Age-dependent visual exploration during simulated day- and night driving on a motorway: a cross-sectional study

BACKGROUND: Central and peripheral vision is needed for object detection. Previous research has shown that visual target detection is affected by age. In addition, light conditions also influence visual exploration. The aim of the study was to investigate the effects of age and different light conditions on visual exploration behavior and on driving performance during simulated driving. METHODS: A fixed-base simulator with 180 degree field of view was used to simulate a motorway route under daylight and night conditions to test 29 young subjects (25-40 years) and 27 older subjects (65-78 years). Drivers' eye fixations were analyzed and assigned to regions of interests (ROI) such as street, road signs, car ahead, environment, rear view mirror, side mirror left, side mirror right, incoming car, parked car, road repair. In addition, lane-keeping and driving speed were analyzed as a measure of driving performance. RESULTS: Older drivers had longer fixations on the task relevant ROI, but had a lower frequency of checking mirrors when compared to younger drivers. In both age groups, night driving led to a less fixations on the mirror. At the performance level, older drivers showed more variation in driving speed and lane-keeping behavior, which was especially prominent at night. In younger drivers, night driving had no impact on driving speed or lane-keeping behavior. CONCLUSIONS: Older drivers' visual exploration behavior are more fixed on the task relevant ROI, especially at night, when driving performance becomes more heterogeneous than in younger drivers.

The Effects of Heat Acclimation Followed by Sleep Deprivation on Perceived Exertion, Thirst, and Thermal Sensations in Exercising Males

Subjects were tested while walking on a tradmill for 11 days in a row at sub-maximal levels for 90 minutes the heat. After the 10th day, subjects were kept awake for 24 hours before being tested in a state of sleep deprivation on the 11th day. Subjects rated their perceived exertion, thirst levels, and thermal sensations at regular intervals before, during, and after exercise each day. The changes in RPE, thirst, and thermal sensations were examined to determine the progression of heat acclimation and to observe changes in the subjects' perceived workloads. While subjects were significantly less thirsty on day 10 than when beginning the study on day 1, no significant changes occured in regards to thermal sensations or RPE values. On the 11th day, these variables were again observed in order to examine the effects of sleep deprivation on the adaptations of heat acclimation. After 28 hours of sleep loss, subjects rated themselves as feeling significantly more thristy after exercise than they had on day 10, yet again there was no significant change in thermal sensations or RPE values. Throughout the study, RPE and thermal sensation ratings seemed to be closely linked while sensations of thirst fluctuated independently.

Preselection of retrovirally transduced bone marrow avoids subsequent stem cell gene silencing and age-dependent extinction of expression of human β-globin in engrafted mice

Transcriptional silencing of genes transferred into hematopoietic stem cells poses one of the most significant challenges to the success of gene therapy. If the transferred gene is not completely silenced, a progressive decline in gene expression as the mice age often is encountered. These phenomena were observed to various degrees in mouse transplant experiments using retroviral vectors containing a human β-globin gene, even when cis-linked to locus control region derivatives. Here, we have investigated whether ex vivo preselection of retrovirally transduced stem cells on the basis of expression of the green fluorescent protein driven by the CpG island phosphoglycerate kinase promoter can ensure subsequent long-term expression of a cis-linked β-globin gene in the erythroid lineage of transplanted mice. We observed that 100% of mice (n = 7) engrafted with preselected cells concurrently expressed human β-globin and the green fluorescent protein in 20–95% of their RBC for up to 9.5 mo posttransplantation, the longest time point assessed. This expression pattern was successfully transferred to secondary transplant recipients. In the presence of β-locus control region hypersensitive site 2 alone, human β-globin mRNA expression levels ranged from 0.15% to 20% with human β-globin chains detected by HPLC. Neither the proportion of positive blood cells nor the average expression levels declined with time in transplanted recipients. Although suboptimal expression levels and heterocellular position effects persisted, in vivo stem cell gene silencing and age-dependent extinction of expression were avoided. These findings support the further investigation of this type of vector for the gene therapy of human hemoglobinopathies.