Systemic Capillary Responses to Acute Exercise in Hypertensive Seniors: Insights from a Single-Center Pilot Study.

Objective: The aim of this study was to investigate nailfold capillary parameters in community-dwelling individuals aged over 60 years who have hypertension and do not exercise regularly. Furthermore, the study examined the correlations between capillary function and other health-related indicators. DESIGN: This study was a single- center pilot trial. SETTING: The study took place in the Faculty of Health, Tsukuba University of Technology, Japan. PARTICIPANTS: Hypertensive community-dwelling elderly people took part in the study. INTERVENTION: Microcirculation was observed before and 1 min after an arm-curl exercise by means of capillary microscopy of the non-exercised limb. Additionally, we examined other health-related indicators. Methods: We measured the acute effects of reperfusion on nailfold density, flow, and diameters. Secondary outcomes included the correlations between microvascular parameters and other health-related indicators. We hypothesized that brief exercise could enhance microcirculation reperfusion and correlate with other health-related parameters. Results: There were 20 participants with a mean (SD) age of 67.1 (5.8) years. The capillary flow rate changed from 2.3 ± 6.7 to 2.7 ± 0.2 log µm/s (p < 0.01), and the capillary density changed from 0.8 ± 0.2 to 0.9 ± 0.1 log/mm (p < 0.01), which included a significant increase in the non-exercising limb. Significant correlations were observed between the nailfold capillary diameter and body fat mass, the capillary diameter and physical activity, and the capillary density and bone mineral density. Conclusions: The acute effects of exercise on high-risk elderly individuals can be safe, and even 1 of min exercise can potentially improve their nailfold capillary function, despite the brief time, compared to no exercise. The results indicate that capillaries have an impact on the function of the whole body. Thus, they may be a useful diagnostic tool for assessing nailfold capillaries.

Three-dimensional kinematics analysis of blind football kicking.

The purpose of this study was to identify critical technical points that lead to increased ball speed in a maximal toe kick with no run-up (a 'static kick') in blind football. Six visually impaired male players and eight sighted male players participated in the experiment. All participants wore a blindfold to fully remove visual information and performed the static kick. The motion was captured three-dimensionally using an optical motion analysis system. Our results demonstrated that ball speed, maximum linear velocity of the kicking-side thigh, and maximum angular velocity of the kicking-side shank for the sighted player group were significantly greater than those for the visually impaired player group. The sighted players tended to perform the static kick in a similar motion pattern, which was characterised by a backwards rotation of the torso to adequately extend the kicking-side hip joint during the back-swing phase and a stable posture of the lower torso on the frontal plane during the forward-swing phase. This motion pattern is critical to both acceleration of the kicking-side foot and orientation of the foot for a more precise ball contact position.

Effect of a leucine-enriched essential amino acids mixture on muscle recovery.

[Purpose] The aim of this study was to determine whether the consumption of a leucine-enriched essential amino acid mixture (LEAA), which is known to increase protein synthesis in muscles, alleviates muscle damage and accelerates recovery by ameliorating muscle damage. [Participants and Methods] A double-blind, randomized crossover trial was conducted over a 5-week period. Ten untrained males (age, 23.0 ± 1.6 years) were asked to repeatedly flex and extend their elbows for 10 counts/set × 5 sets at full power while using a dynamometer. The participants took 3.6-g supplements (LEAA mixture or placebo) 3 times daily on day 0 and for the next 7 days. Changes in serum creatine phosphokinase (CPK) activity and myoglobin concentration as markers of muscle tissue damage were evaluated prior to and after exercise and on days 1, 2, 3, 5, and 7. [Results] The relative ratio of the changes in peak serum CPK activity measured on day 5 was significantly lower after taking LEAA than after taking the placebo. [Conclusion] LEAA consumption suppressed exercise-induced elevation of muscle damage markers in blood, which suggests that LEAA could attenuate muscle damage and aid muscle recovery.

Trunk muscle activity with different sitting postures and pelvic inclination.

BACKGROUND AND OBJECTIVE: Sitting posture may often place large burden on trunk muscles, while trunk muscle activities in the sitting posture have not been well clarified. In this study, a difference in trunk muscle activity between two kinds of sitting postures was evaluated, focusing on low back pain induced by posture holding. MATERIAL AND METHODS: An experiment was conducted on the subjects sitting on a stable-seat and on an unstable-seat, with the pelvis inclined forward, backward, rightward, and leftward. RESULTS: With the pelvis inclined forward, rightward and leftward, muscle activities were significantly increased in a stable-seat sitting posture. In contrast, no significant increase in muscle activity was observed with the pelvis inclined in every direction in an unstable-seat sitting posture. CONCLUSIONS: With the pelvis inclined in the stable-seat sitting posture, muscle activities were imbalanced, while with the pelvis inclined in the unstable-seat sitting posture, muscle activities were not imbalanced. Thus, it is suggested that with the pelvis inclined to the maximum extent in the stable-seat sitting posture, low back pain may be induced by imbalanced muscle activities.

Pilot study: Effects of drinking hydrogen-rich water on muscle fatigue caused by acute exercise in elite athletes.

BACKGROUND: Muscle contraction during short intervals of intense exercise causes oxidative stress, which can play a role in the development of overtraining symptoms, including increased fatigue, resulting in muscle microinjury or inflammation. Recently it has been said that hydrogen can function as antioxidant, so we investigated the effect of hydrogen-rich water (HW) on oxidative stress and muscle fatigue in response to acute exercise. METHODS: Ten male soccer players aged 20.9 ± 1.3 years old were subjected to exercise tests and blood sampling. Each subject was examined twice in a crossover double-blind manner; they were given either HW or placebo water (PW) for one week intervals. Subjects were requested to use a cycle ergometer at a 75 % maximal oxygen uptake (VO2) for 30 min, followed by measurement of peak torque and muscle activity throughout 100 repetitions of maximal isokinetic knee extension. Oxidative stress markers and creatine kinase in the peripheral blood were sequentially measured. RESULTS: Although acute exercise resulted in an increase in blood lactate levels in the subjects given PW, oral intake of HW prevented an elevation of blood lactate during heavy exercise. Peak torque of PW significantly decreased during maximal isokinetic knee extension, suggesting muscle fatigue, but peak torque of HW didn't decrease at early phase. There was no significant change in blood oxidative injury markers (d-ROMs and BAP) or creatine kinease after exercise. CONCLUSION: Adequate hydration with hydrogen-rich water pre-exercise reduced blood lactate levels and improved exercise-induced decline of muscle function. Although further studies to elucidate the exact mechanisms and the benefits are needed to be confirmed in larger series of studies, these preliminary results may suggest that HW may be suitable hydration for athletes.

Mmr1p is a mitochondrial factor for Myo2p-dependent inheritance of mitochondria in the budding yeast.

Class V myosins play a pivotal role in organelle distribution. In the budding yeast, Myo2p, a class V myosin, is essential for mitochondrial distribution. We identified MMR1 as a high-dose suppressor of the myo2 mitochondrial defect and that Mmr1p resides restrictively on the bud-localizing mitochondria and forms a complex with Myo2p tail. Mmr1p loss delayed mitochondrial transfer to buds and completely abolished mitochondrial distribution in the absence of Ypt11p, which promotes mitochondrial distribution by complex formation with Myo2p tail. The myo2-573 mutation, which causes a mitochondrial distribution defect and inactivates the Mmr1p function, reduced association between Myo2p and Mmr1p and depolarized Mmr1p localization on mitochondria. These strongly suggest that Mmr1p is a key mitochondrial component of the link between Myo2p and mitochondria for Myo2p-dependent mitochondrial distribution. Genetical analysis revealed that the Mmr1p-Myo2p pathway is independent of the Ypt11p-Myo2p pathway, suggesting that an essential system for mitochondrial distribution is composed of two independent Myo2p pathways.

Polarized distribution of intracellular components by class V myosins in Saccharomyces cerevisiae.

The budding yeast Saccharomyces cerevisiae has three classes of myosins corresponding to three actin structures: class I myosin for endocytic actin structure, actin patches; class II myosin for contraction of the actomyosin contractile ring around the bud neck; and class V myosin for transport along a cable-like actin structure (actin cables), extending toward the growing cortex. Myo2p and Myo4p constitute respective class V myosins as the heavy chain and, like class V myosins in other organisms, function as actin-based motors for polarized distribution of organelles and intracellular molecules. Proper distribution of organelles is essential for autonomously replicating organelles that cannot be reproduced de novo, and is also quite important for other organelles to ensure their efficient segregation and proper positioning, even though they can be newly synthesized, such as those derived from endoplasmic reticulum. In the budding yeast, microtubule-based motors play limited roles in the distribution. Instead, the actin-based motor myosins, especially Myo2p, play a major role. Studies on Myo2p have revealed a wide variety of Myo2p cargo and Myo2p-interacting proteins and have established that Myo2p interacts with cargo and transfers it along actin cables. Moreover, recent findings suggest that Myo2p has another way to distribute cargo in that Myo2p conveys the attaching cargo along the actin track. Thus, the myosin have "dual paths" for distribution of a cargo. This dual path mechanism is proposed in the last section of this review.

The small GTPase Rho3 and the diaphanous/formin For3 function in polarized cell growth in fission yeast.

We identified a novel Rho gene rho3(+) and studied its interaction with diaphanous/formin for3(+) in the fission yeast Schizosaccharomyces pombe. Both rho3 null cells and for3 null cells showed defects in organization of not only actin cytoskeleton but also cytoplasmic microtubules (MTs). rho3 for3 double null cells had defects that were more severe than each single null cell: polarized growth was deficient in the double null cells. Function of For3 needed the highly conserved FH1 and FH2 domains, an N-terminal region containing a Rho-binding domain, and the C-terminal region. For3 bound to active forms of both Rho3 and Cdc42 but not to that of Rho1. For3 was localized as dots to the ends of interphase cells and to the mid-region in dividing cells. This localization was probably dependent on its interaction with Rho proteins. Overexpression of For3 produced huge swollen cells containing depolarized F-actin patches and thick cytoplasmic MT bundles. In addition, overexpression of a constitutively active Rho3Q71L induced a strong defect in cytokinesis. In conclusion, we propose that the Rho3-For3 signaling system functions in the polarized cell growth of fission yeast by controlling both actin cytoskeleton and MTs.

Complex formation with Ypt11p, a rab-type small GTPase, is essential to facilitate the function of Myo2p, a class V myosin, in mitochondrial distribution in Saccharomyces cerevisiae.

We identified Ypt11p, a rab-type small GTPase, by its functional and two-hybrid interaction with Myo2p, a class V myosin of the budding yeast Saccharomyces cerevisiae. The tail domain of Myo2p was coimmunoprecipitated with Ypt11p, suggesting that Ypt11p forms a complex with Myo2p at its tail domain in vivo. Mutational analysis of YPT11 suggests that Myo2p is a putative effector of Ypt11p. Deletion of YPT11 induced partial delay of mitochondrial transmission to the bud, and overexpression of YPT11 resulted in mitochondrial accumulation in the bud, indicating that Ypt11p acts positively on mitochondrial distribution toward the bud. We isolated two myo2 mutants, myo2-338 and myo2-573, which showed genetic interactions with YPT11. The myo2-573 mutation, identified by a synthetic lethal interaction with ypt11-null, induced a defect in mitochondrial distribution toward the bud, indicating that Myo2p plays a crucial role in polarized distribution of mitochondria. The myo2-338 mutation was identified as the mutation that abolished the effect of overexpressed YPT11, such as the Ypt11p-dependent accumulation of mitochondria in the bud, and the affinity of Myo2p for Ypt11p was reduced. These results indicate that complex formation of Ypt11p with Myo2p accelerates the function of Myo2p for mitochondrial distribution toward the bud.

Rpf2p, an evolutionarily conserved protein, interacts with ribosomal protein L11 and is essential for the processing of 27 SB Pre-rRNA to 25 S rRNA and the 60 S ribosomal subunit assembly in Saccharomyces cerevisiae.

Saccharomyces cerevisiae Rrs1p is a nuclear protein that is essential for the maturation of 25 S rRNA and the 60 S ribosomal subunit assembly. In two-hybrid screening, using RRS1 as bait, we have cloned YKR081c/RPF2. Rpf2p is essential for growth and is mainly localized in the nucleolus. The amino acid sequence of Rpf2p is highly conserved in eukaryotes from yeast to human. Similar to Rrs1p, Rpf2p shows physical interaction with ribosomal protein L11 and appears to associate with preribosomal subunits fairly tightly. Northern, methionine pulse-chase, and sucrose density gradient ultracentrifugation analyses reveal that the depletion of Rpf2p results in a delayed processing of pre-rRNA, a decrease of mature 25 S rRNA, and a shortage of 60 S subunits. An analysis of processing intermediates by primer extension shows that the Rpf2p depletion leads to an accumulation of 27 SB pre-rRNA, suggesting that Rpf2p is required for the processing of 27 SB into 25 S rRNA.

Normal assembly of 60 S ribosomal subunits is required for the signaling in response to a secretory defect in Saccharomyces cerevisiae.

A secretory defect leads to transcriptional repression of both ribosomal protein and rRNA genes in yeast. To elucidate the mechanism of the signaling, we previously isolated rrs mutants that were unable to respond to a secretory defect, and we cloned RRS1 encoding a nuclear protein that was required for ribosome biogenesis (Tsuno, A., Miyoshi, K., Tsujii, R., Miyakawa, T., and Mizuta, K. (2000) Mol. Cell. Biol. 20, 2066-2074). We identified duplicated genes encoding ribosomal protein L11, RPL11B as a wild-type allele complementing the rrs2 mutation, and RPL11A in two-hybrid screening using RRS1 as bait. Rpl11p was copurified with Rrs1p in immunoprecipitation analysis. Ultracentrifugation analysis revealed that Rrs1p associated fairly tightly with 60 S preribosomal subunits. These results suggest that signaling in response to a secretory defect requires the normal assembly of 60 S ribosomal subunits including Rrs1p and Rpl11p.