Search results for "LK"
showing 10 items of 8438 documents
Physical Activity Scaled to Preferred Walking Speed as a Predictor of Walking Difficulty in Older Adults: A 2-Year Follow-up
2021
Abstract Background The usual accelerometry-based measures of physical activity (PA) are dependent on physical performance. We investigated the associations between PA relative to walking performance and the prevalence and incidence of early and advanced walking difficulties compared to generally used measures of PA. Methods Perceived walking difficulty was evaluated in 994 community-dwelling participants at baseline (age 75, 80, or 85 years) and 2 years later over 2 km (early difficulty) and 500 m (advanced difficulty). We used a thigh-mounted accelerometer to assess moderate-to-vigorous PA, daily mean acceleration, and relative PA as movement beyond the intensity of preferred walking spee…
Effects of strength and endurance training on isometric muscle strength and walking speed in elderly women
1996
The separate effects of 18 weeks of intensive strength and endurance training on isometric knee extension (KE) and flexion (KF) strength and walking speed were studied in 76- to 78- year-old women. Maximal voluntary isometric force for both KE and KF was measured in a sitting position on a custom-made dynamometer chair at a knee angle of 60 degrees from full extension. Maximal walking speed was measured over a distance of 10 m. The endurance-trained women increased KE torque and KE torque/body mass after the first 9 weeks of training when compared with the controls. when comparing the baseline, 9 week and 18 week measurements within the groups separately, both the endurance- and strength-tr…
Coimpairments as Predictors of Severe Walking Disability in Older Women
2001
OBJECTIVE: Severe disabilities are common among older people who have impairments in a range of physiologic systems. It is not known, however, whether the presence of multiple impairments, or coimpairments, is associated with increased risk of developing new disability. The aim of this study was to determine the combined effects of two impairments, decreased knee-extension strength and poor standing balance, on the risk of developing severe walking disability among older, moderately-to-severely disabled women who did not have severe walking disability at baseline. DESIGN: The Women's Health and Aging Study is a 3-year prospective study with 6 semi-annual follow-up data-collection rounds fol…
Age-associated oxidative damage leads to absence of γ-cystathionase in over 50% of rat lenses: Relevance in cataractogenesis
2004
Oxidative damage to lens proteins and glutathione depletion play a major role in the development of senile cataract. We previously found that a deficiency in gamma-cystathionase activity may be responsible for glutathione depletion in old lenses. The aims of this study were: (1) to investigate the mechanism that causes the age-related deficiency in gamma-cystathionase activity in the eye lens, and (2) to determine the role of gamma-cystathionase deficiency in cataractogenesis. Two populations of old rats were found, one (56%) whose lenses lacked gamma-cystathionase activity and the rest that exhibited detectable enzyme activity. gamma-Cystathionase protein was absent in lenses from old rats…
Ankle and knee extensor muscle effort during locomotion in young and older athletes : Implications for understanding age-related locomotor decline
2019
AbstractAge-related reduction in muscle force generation capacity is similarly evident across different lower limb muscle groups, yet decline in locomotor performance with age has been shown to depend primarily on reduced ankle extensor muscle function. To better understand why ageing has the largest detrimental effect on ankle joint function during locomotion, we examined maximal ankle and knee extensor force development during a two-leg hopping test in older and young men, and used these forces as a reference to calculate relative operating efforts for the knee and ankle extensors as participants walked, ran and sprinted. We found that, across locomotion modes in both age groups, ankle ex…
Association between arterial stiffness and walking capacity in older adults
2022
Background and aim: Arterial stiffening – a process that is largely due to intimal thickening, collagen disposition or elastin fragmentation – significantly contributes to cardiovascular events and mortality. There is also some evidence that it may negatively affect physical function. This study aimed to evaluate whether arterial stiffness was associated with measures of walking capacity in a large, population-based sample of highly aged older adults.Methods: A population-based sample of 910 community-dwelling adults (aged 75, 80, or 85 years) were investigated in a cross-sectional observational study. Pulse wave velocity (PWV), a surrogate marker of arterial stiffness, was estimated based …
The 5-HT and alpha-adrenoceptor antagonist effect of four benzylisoquinoline alkaloids on rat aorta.
1998
Abstract The action of four benzylisoquinoline alkaloids (two aporphines—glaucine and apomorphine, a benzylisoquinoline—papaverine and a bisbenzyltetrahydroisoquinoline—antioquine) on 5-HT-induced contraction in rat thoracic aorta has been examined and compared with that of the control drugs: ketanserin, nifedipine, prazosin and phentolamine. The relaxant action on 5-HT-induced contraction was contrasted with that on the contraction induced by noradrenaline and KCl. The results obtained with control drugs show that ketanserin has clear selectivity for 5-HT receptors, whereas prazosin and phentolamine have high selectivity for the α1-adrenoceptor and nifedipine seems to have a more potent ef…
Darstellung und H2-agonistische Aktivität alkylsubstituierter 3-(Imidazol-4-yl)propylguanidine Synthesis and H2-Agonistic Activity of Alkyl-3-(imidaz…
1987
Derivate des 3-(Imidazol-4-yl)propylguanidins mit einem Methyl- oder einem 2-(Ethylthio)ethyl-Substituenten2) an der Guanidin-Gruppe weisen am H2-Rezeptor des Meerschweinchenvorhofs nur 10–20% der Histaminaktivitat auf. Dagegen fuhrt die Substitution mit der H2-affinen 2-[(5-Methylimidazol-4-yl) methylthio]ethyl-Gruppierung zu Impromidin, einem hochpotenten H2-Agonisten.
Postnatal alterations of the inhibitory synaptic responses recorded from cortical pyramidal neurons in the Lis1/sLis1 mutant mouse
2006
Mutations in the mouse Lis1 gene produce severe alterations in the developing cortex. We have examined some electrophysiological responses of cortical pyramidal neurons during the early postnatal development of Lis/sLis1 mutant mice. In P7 and P30 Lis1/sLis1 neurons we detected a lower frequency and slower decay phase of mIPSCs, and at P30 the mIPSCs amplitude and the action potential duration were reduced. Zolpidem (an agonist of GABAA receptors containing the alpha1 subunit) neither modified the amplitude nor the decay time of mIPSCs at P7 in Lis1/sLis1 neurons, whereas it increased the decay time at P30. The levels of GABAA receptor alpha1 subunit mRNA were reduced in the Lis1/sLis1 brai…
Qualitative Analysis of Feed Management Practice on Goat Herds by Self Organizing Maps in Murcia Region of Spain
2007
Abstract Fernandez, C., Soria, E., Magdalena, R., Martin, J.D. and Mata, C. 2007. Qualitative analysis of feed management practice on goat herds by self organizing maps in Murcia region of Spain. J. Appl. Anim. Res., 32: 41–47. Self organizing maps (SOM) were used to analyze data from ninety four herds. Data were obtained from surveys and management practices were evaluated. The 18% of farms were dairy goat farms with milking machines, with a herd size of 100 to 200 goats and most of these bought compound feed. 12% has the same characteristics but farmers prepared their own diet. 16% were similar to previous prototypes, but farmers in addition to dairy goat production kept sheep as well. 23…