Effects of high-intensity intermittent exercise versus moderate-intensity continuous exercise on renal hemodynamics assessed by ultrasound echo.

High-intensity intermittent exercise (HIIE) has become attractive for presenting a variety of exercise conditions. However, the effects of HIIE on renal function and hemodynamics remain unclear. This study aimed to compare the effects of HIIE and moderate-intensity continuous exercise (MICE) on renal hemodynamics, renal function, and kidney injury biomarkers. Ten adult males participated in this study. We allowed the participants to perform HIIE or MICE to consider the impact of exercise on renal hemodynamics under both conditions. Renal hemodynamic assessment and blood sampling were conducted before the exercise (pre) and immediately (post 0), 30 min (post 30), and 60 min (post 60) after the exercise. Urine sampling was conducted in the pre, post 0, and post 60 phases. There was no condition-by-time interaction (p = 0.614), condition (p = 0.422), or time effect (p = 0.114) regarding renal blood flow. Creatinine-corrected urinary neutrophil gelatinase-associated lipocalin concentrations increased at post 60 (p = 0.017), but none exceeded the cut-off values for defining kidney injury. Moreover, there were no significant changes in other kidney injury biomarkers at any point. These findings suggest that high-intensity exercise can be performed without decreased RBF or increased kidney injury risk when conducted intermittently for short periods.

The differences in renal hemodynamic response following high-intensity exercise between younger and older males.

BACKGROUND: Renal blood flow (RBF) decreases with exercise, but this change is only temporary, and habitual exercise may be an effective method to improve renal function. The kidney shows structural and functional changes with aging, but it is unclear how aging affects the hemodynamic response of the kidneys to exercise. Therefore, we evaluated the differences in the hemodynamic response of the kidneys to high-intensity exercise between younger and older men. METHODS: Sixteen men (8 young and 8 older) underwent an incremental exercise test using a cycle ergometer with a 1-min warm up followed by exercise at 10-20 W/min until the discontinuation criteria were met. Renal hemodynamics were assessed before exercise, immediately after exercise, and at 60-min after exercise using ultrasound echo. RESULTS: High-intensity exercise significantly reduced RBF in both groups (younger: ∆ - 53 ± 16%, p = 0.0005; older: ∆ - 53 ± 19%, p = 0.0004). In the younger group, RBF returned to the pre-exercise level 60-min after exercise (∆ - 0.4 ± 5.7%, p > 0.9999). In contrast, RBF 60-min after exercise was significantly lower than that before exercise in the older group (∆ - 24 ± 19%, p = 0.0006). The older group had significantly lower RBF than younger adults 60-min after exercise (423 ± 32 vs. 301 ± 98 mL/min, p = 0.0283). CONCLUSIONS: Our findings demonstrate that RBF following high-intensity exercise recovered 60-min after exercise in younger group, whereas RBF recovery was delayed in the older group.

Effects of noisy galvanic vestibular stimulation on functional reach test.

Balance disorders are a risk factor for falls in older individuals, and an increased center of pressure (COP) sway path length during standing and decreased reach distance in the functional reach test (FRT) predispose them to falls. Reportedly, noisy galvanic vestibular stimulation (nGVS) reduces COP sway path length during standing in young and community-dwelling older individuals and suggested to be a promising approach to improve balance function. However, the effect of nGVS on FRT remains unclear. Therefore, this study aimed to clarify the effect of nGVS on the FRT reach distance. This study has a cross-over design and included 20 healthy young adults. Interventions under nGVS (stimulation intensity: 0.2 mA) and sham (stimulation intensity: 0 mA) conditions were randomly administered to each participant. The participants underwent COP sway during standing measurements and FRT pre-intervention and post-intervention under each condition, and COP sway path length and the FRT reach distance were calculated. Statistical analysis revealed a significant decrease in post-intervention COP sway path length compared with pre-intervention COP sway path length under the nGVS condition. Conversely, the FRT reach distance remained the same under both nGVS and sham conditions. Thus, nGVS may improve the standing balance function but cannot change the FRT reach distance in healthy young individuals.

The Validity of Ultra-Short-Term Heart Rate Variability during Cycling Exercise.

Ultra-short-term heart rate variability (HRV) has been validated in the resting state, but its validity during exercise is unclear. This study aimed to examine the validity in ultra-short-term HRV during exercise considering the different exercise intensities. HRVs of twenty-nine healthy adults were measured during incremental cycle exercise tests. HRV parameters (Time-, frequency-domain and non-linear) corresponding to each of the 20% (low), 50% (moderate), and 80% (high) peak oxygen uptakes were compared between the different time segments of HRV analysis (180 s (sec) segment vs. 30, 60, 90, and 120-sec segments). Overall, the differences (bias) between ultra-short-term HRVs increased as the time segment became shorter. In moderate- and high-intensity exercises, the differences in ultra-short-term HRV were more significant than in low intensity exercise. Thus, we discovered that the validity of ultra-short-term HRV differed with the duration of the time segment and exercise intensities. However, the ultra-short-term HRV is feasible in the cycling exercise, and we determined some optimal time duration for HRV analysis for across exercise intensities during the incremental cycling exercise.

The moderate-intensity continuous exercise maintains renal blood flow and does not impair the renal function.

Exercise is restricted for individuals with reduced renal function because exercising reduces blood flow to the kidneys. Safe and effective exercise programs for individuals with reduced renal function have not yet been developed. We previously examined the relationship between exercise intensity and renal blood flow (RBF), revealing that moderate-intensity exercise did not reduce RBF. Determining the effects of exercise duration on RBF may have valuable clinical applications. The current study examined the effects of a single bout of continuous exercise at lactate threshold (LT) intensity on renal hemodynamics. Eight adult males participated in this study. Participants underwent 30 min of aerobic exercise at LT intensity using a cycle ergometer. Evaluation of renal hemodynamics was performed before and after exercise, in the recovery phase using ultrasound echo. Furthermore, blood and urine samplings were conducted before and after exercise, in the recovery phase. Compared with resting, RBF was not significantly changed immediately after continuous exercise (319 ± 102 vs. 308 ± 79 ml/min; p = 0.976) and exhibited no significant changes in the recovery phase. Moreover, urinary kidney injury molecule-1 (uKIM-1) level exhibited no significant change immediately after continuous exercise (0.52 ± 0.20 vs. 0.46 ± 0.27 µg/g creatinine; p = 0.447). In addition, the results revealed no significant change in urinary uKIM-1 in 60-min after exercise. Other renal injury biomarkers exhibited a similar pattern. These findings indicate that a single bout of moderate-intensity continuous exercise maintains RBF and does not induce renal injury.

Transcranial direct current stimulation and transcranial random noise stimulation over the cerebellum differentially affect the cerebellum and primary motor cortex pathway.

Transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS) are two methods of noninvasively modulating cortical excitability below the placed electrode. Anodal tDCS over the cerebellum has been shown to modulate cerebellar brain inhibition (CBI), which is an indication of cerebellar excitability, but does not alter contralateral M1 excitability. However, the effect of tRNS over the cerebellum has not been investigated. The purpose of this study was thus to compare the effects of tDCS and tRNS over the cerebellum on CBI and the contralateral motor evoked potentials (MEPs), as well as on the relationship between CBI and contralateral MEPs. A total of 15 healthy subjects completed four-condition transcranial electrical stimulation (tES) interventions (anodal tDCS_1 mA, anodal tDCS_2 mA, tRNS, and Sham) on separate days. CBI and MEPs were measured using transcranial magnetic stimulation (TMS) before and after the 20 min tES intervention. For all conditions, there were no significant differences before and after tES in CBI or contralateral MEPs. In contrast, following tRNS, changes in CBI and MEPs were significantly correlated. No significant correlations were found in the other three conditions, indicating that cerebellar tDCS and tRNS have distinct effects on the relationship between CBI and contralateral MEPs. Taken together, these findings suggest that cerebellar tRNS may modulate the cerebellar to contralateral M1 pathway.

Single-Session Cerebellar Transcranial Direct Current Stimulation Affects Postural Control Learning and Cerebellar Brain Inhibition in Healthy Individuals.

Cerebellar transcranial direct current stimulation (ctDCS) modulates cerebellar activity and postural control. However, the effects of ctDCS on postural control learning and the mechanisms associated with these effects remain unclear. To examine the effects of single-session ctDCS on postural control learning and cerebellar brain inhibition (CBI) of the primary motor cortex in healthy individuals. In this triple-blind, sham-controlled study, 36 participants were allocated randomly to one of three groups: (1) anodal ctDCS group, (2) cathodal ctDCS group, and (3) sham ctDCS group. ctDCS (2 mA) was applied to the cerebellar brain for 20 min prior to six blocks of standing postural control training (each block consisted of five trials of a 30-s tracking task). CBI and corticospinal excitability of the tibialis anterior muscle were assessed at baseline, immediately after, 1 day after, and 7 days after training. Skill acquisition following training was significantly reduced in both the anodal and cathodal ctDCS groups compared with the sham ctDCS group. Changes in performance measured 1 day after and 7 days after training did not differ among the groups. In the anodal ctDCS group, CBI significantly increased after training, whereas corticospinal excitability decreased. Anodal ctDCS-induced CBI changes were correlated with the learning formation of postural control (r = 0.55, P = 0.04). Single-session anodal and cathodal ctDCS could suppress the skill acquisition of postural control in healthy individuals. The CBI changes induced by anodal ctDCS may affect the learning process of postural control.

High-resolution 3D-MRI of postmortem brain specimens fixed by formalin and gadoteridol.

PURPOSE: The purpose of this investigation was to compare magnetization-prepared rapid gradient echo (MP-RAGE) images with T1-weighted images (T1WI) and T2-weighted images (T1W2) of postmortem brain tissue fixed by admixtures of formalin and gadoteridol. We additionally sought to explore the feasibility of using fixed brain magnetic resonance imaging (MRIs) in forensic practices. METHODS: Specimens included in the study were eight whole brains that had been removed during forensic autopsy. Brain specimens were randomly divided into three groups and MRIs were performed either (A) the day of autopsy (n=2) on unfixed tissue, (B) after immersion fixation in 20% formalin (n=3), or (C) after immersion fixation in 20% formalin mixed with 4 mL/L ProHance® (gadoteridol) (n=3). T1WI, T2WI, and MP-RAGE images of all group samples were acquired with a 3T clinical MR scanner. Gray and white matter contrasts of the cortex and basal nucleus in every fixation group and image sequence were then visually compared. RESULTS: Gray/white matter contrasts of the cortex were good in all images obtained by MP-RAGE, and T1WIs of specimens fixed by formalin and gadoteridol-mixed formalin. Additionally, gray/white matter contrast in the basal nucleus was sufficient in the MP-RAGE sequence of specimens fixed by gadoteridol-mixed formalin. CONCLUSIONS: MRI of brains immersion-fixed in formalin and gadolinium could serve as a promising tool for neuropathological assessment in forensic practices.

Bacteremia due to Mycobacterium massiliense in a patient with chronic myelogenous leukemia: case report.

Bacteremia due to Mycobacterium massiliense is rare. We present here the case of a 58-year-old man with chronic myelogenous leukemia complicated by bacteremia caused by M. massiliense. The microorganisms were identified as M. massiliense by sequencing analysis, having initially been misdiagnosed as M. abscessus by DNA-DNA hybridization.

ERK2 dependent signaling contributes to wound healing after a partial-thickness burn.

Burn healing is a complex physiological process involving multiple cell activities, such as cell proliferation, migration and differentiation. Although extracellular signal-regulated kinases (ERK) have a pivotal role in regulating a variety of cellular responses, little is known about the individual functions of ERK isoform for healing in vivo. This study investigated the role of ERK2 in burn healing. To assess this, Erk2(+/-) mice generated by gene targeting were used. The resultant mice exhibited significant delay in re-epithelization of partial-thickness burns in the skin in comparison to wild-type. An in vitro proliferation assay revealed that keratinocytes from Erk2(+/-) mice grew significantly slower than those prepared from wild-type. These results highlight the importance of ERK2 in the process of burn healing.