Activation of STING in pancreatic cancer-associated fibroblasts exerts an antitumor effect by enhancing tumor immunity.

Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate; therefore, the development of effective treatments is a priority. The stimulator of interferon genes (STING) pathway enhances tumor immunity by inducing the production of type 1 interferon (IFN) and proinflammatory cytokines and chemokines and promoting the infiltration of cytotoxic T cells. To assess the function of STING on pancreatic tumorigenesis, Ptf1aER-Cre/+ LSL-KrasG12D/+ p53loxP/loxP mice (KPC mice) and Ptf1aER-Cre/+ LSL-KrasG12D/+ p53loxP/loxP/STING-/- mice (KPCS mice) were generated. However, STING deletion did not affect pancreatic tumorigenesis in mice. Because STING is expressed not only in immune cells but also in cancer-associated fibroblasts (CAFs), we evaluated the STING function in PDAC CAFs. A mouse STING agonist 5,6-Dimethyl-9-oxo-9H-xanthene-4-acetic acid (DMXAA) was administered to KPC mice and CAFs from KPC mice and the resulting immune response was evaluated. DMXAA activated STING in PDAC CAFs in KPC mice, promoting cytotoxic T cell infiltration by secreting proinflammatory cytokines and enhancing tumor immunity. We next generated STING-deficient PDAC cells and subcutaneous tumors in which STING was expressed only in CAFs by performing bone marrow transplantation and assessed the antitumor effect of STING-activated CAFs. The administration of DMXAA to subcutaneous tumors expressing STING only in CAFs sustained the antitumor effect of DMXAA. About half of human PDACs lacked STING expression in the cancer stroma, suggesting that STING activation in PDAC CAFs exerts an antitumor effect, and STING agonists can be more effective in tumors with high than in those with low STING expression in the stroma.

Risk assessment of metachronous gastric cancer after endoscopic submucosal dissection based on endoscopic intestinal metaplasia.

Background and Aim: The incidence of metachronous gastric cancer (MGC) after endoscopic treatment for early gastric cancer (EGC) is high, but a method of risk assessment for MGC based on endoscopic findings has not been established. In this study, we focused on endoscopic intestinal metaplasia (IM) and investigated the risk for MGC after endoscopic submucosal dissection (ESD) for EGC. Methods: This retrospective observational study involved patients who underwent curative ESD for EGC from April 2015 to January 2021. We assessed endoscopic IM using the pretreatment endoscopic examination images. The severity of endoscopic IM was classified into four levels: 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Four different gastric areas were evaluated. We divided the patients into a low-score group and a high-score group, and compared the cumulative incidence of MGC. Results: In total, 156 patients who met the inclusion criteria were followed up for at least 12 months after ESD, and MGC developed in 14 patients during a mean period oof 41.5 months. The endoscopic IM scores in the lesser curvature of the antrum, lesser curvature of the corpus, and greater curvature of the corpus were higher in patients with MGC than in those without MGC. In the corpus, the 5-year cumulative incidence of MGC was significantly higher in the high-score group than in the low-score group (29.8% vs 10.0%, P = 0.004). Conclusion: The severity of endoscopic corpus IM was associated with MGC. Thus, patients with severe corpus IM at the time of ESD require careful examination and intensive follow-up.

Subacute In-Stent Occlusion 2 Weeks after CASPER Rx Stenting: A Case Report.

Objective: CASPER Rx stent (Terumo, Tokyo, Japan) is one of the dual-layer micromesh stents for carotid artery stenosis. Although it is expected to be safe and efficacious even for vulnerable plaque, we report a case of in-stent occlusion 2 weeks after stenting with CASPER Rx stent. Case Presentation: The patient was a 78-year-old man with a symptomatic, severely stenosed lesion of the cervical internal carotid artery (ICA). He had an unstable plaque and underwent carotid artery stenting with the CASPER Rx stent. There were no problems with the procedure or the patient's subsequent course, and he was discharged home 1 week after the procedure. However, on postoperative day 14, the patient had a transit ischemic attack and imaging showed acute occlusion due to thrombus in the stent and in the distal part of the ICA. Mechanical thrombectomy was performed and good recanalization was achieved, but postoperative cerebral infarction was observed and the patient was transferred to other hospital with modified Rankin Scale 2. Conclusion: We experienced a case of in-stent occlusion 2 weeks after stenting with the CASPER Rx stent.

Effects of Irregular Mealtimes on Social and Eating Jet Lags among Japanese College Students.

College students' social and eating jet lags and chronotypes may be related to irregular eating habits. Therefore, we examined the relationship between social and eating jet lags, chronotypes, variability in first and last mealtimes, and non-eating duration, as well as the effects of snacking between dinner and bedtime on social and eating jet lags, chronotypes, and mealtime variation. A total of 1900 Japanese male college students were recruited in this study. Mean wake-up time, bedtime, sleeping time, first and last mealtimes, snacks between meals, non-eating duration, the midpoint of non-eating duration, social and eating jet lags, and chronotype were calculated. Standard deviations in first and last mealtimes, the midpoint of non-eating duration, and the coefficient of variation in non-eating duration were used to evaluate mealtime variations. Mealtime variations were significantly associated with social and eating jet lags, chronotype, the midpoint of non-eating duration, and the difference in first and last mealtime between school holidays and class days. Chronotype and the midpoint of non-eating duration were significantly delayed with increased snacking after dinner. Mealtime variations were significantly lower in those who avoided snacking than in those who did not. Thus, social and eating jet lags and chronotypes are associated with sleep habits and mealtime irregularities.

Examination of sleep factors affecting social jetlag in Japanese male college students.

We hypothesized that social jetlag would be associated with prolonged sleep duration on weekends and irregularities in wake-up time and/or bedtime on weekdays. In total, 1,200 Japanese male college students were included in this study. Participants completed an eight-day sleep diary in which they recorded their wake-up time, bedtime, and sleep duration every day for a week. Mean wake-up time, bedtime, and sleep duration, standard deviations in wake-up time and bedtime, the coefficient of variation in sleep duration, social jetlag, and chronotype were calculated over seven nights. Multiple regression was used to explore the factors influencing social jetlag. Stepwise selection analysis was performed to analyze the parameters identified on multiple regression analysis. The mean chronotype of the included participants was 5.3 ± 1.5; their mean social jetlag value was 1.1 ± 1.0. The mean wake-up time, bedtime, and sleep duration values were 8.5 ± 1.1, 25.0 ± 1.1, and 7.5 ± 1.1 h, respectively. Multiple regression analysis showed five indicators exerting a statistically significant influence on social jetlag. The standard deviation in wake-up time was adopted as the first factor in the stepwise selection analysis. These results show that social jetlag is associated with not only prolonged sleep duration on weekends but also irregularities in wake-up time during the week.

Resection of petroclival clear cell meningioma by the anterior transpetrosal approach: diagnosis of rare pathology and improvement of preoperative hearing disturbance.

Clear cell meningioma is a rare histological variant of meningioma, which often recurs aggressively. This video demonstrates a patient with a petroclival clear cell meningioma, which was resected completely through the anterior transpetrosal approach. The absence of intratumoral spotty signal voids on preoperative susceptibility-weighted imaging (SWI) suggested that the tumor was a meningioma rather than a schwannoma, although typical imaging features of meningioma were not observed. After surgery, the patient's preoperative hearing disturbance improved from class D to class A, which the authors had sometimes experienced in cerebellopontine angle meningioma surgeries. Careful observation over a 2.5-year period revealed no tumor recurrence, without additional treatment. The video can be found here: https://stream.cadmore.media/r10.3171/2022.1.FOCVID21219.

Modulation of subjective peripheral sensation, F-waves, and somatosensory evoked potentials in response to unilateral pinch task measured on the contractile and non-contractile sides.

Depression of the sensory input during voluntary muscle contractions has been demonstrated using electrophysiological methods in both animals and humans. However, the association between electrophysiological responses of the sensory system and subjective peripheral sensation (SPS) during a voluntary muscle contraction remains unclear. This study aimed to describe the changes in SPS, spinal α-motoneuron excitability (F-wave to M-wave amplitude), and somatosensory evoked potentials (SEPs) during a unilateral pinch-grip task. Outcome variables were measured on the side ipsilateral and contralateral to the muscle contraction and at rest (control). Participants were 8 healthy men aged 20.9±0.8 years. The isometric pinch-grip task was performed at 30% of the maximum voluntary isometric force measured for the right and left hands separately. The appearance rate of the F-wave during the task was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and control condition. Although there was no difference in the F-wave latency between hands and the control condition, the amplitude of the F-wave was significantly higher for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. There was no difference in the amplitude of the SEP at N20. However, the amplitude at P25 was significantly lower for the ipsilateral (right) hand than for the contralateral (left) hand and the control condition. The accuracy rate of detecting tactile stimulation, evaluated for 20 repetitions using a Semmes-Weinstein monofilament at the sensory threshold for each participant, was significantly lower during the pinch-grip task for both the ipsilateral (right) and contralateral (left) hands than in the control condition. Overall, our findings show that SPS and neurophysiological parameters were not modulated in parallel during the task, with changes in the subjective sensation preceding changes in electrophysiological indices during the motor task. Our findings provide basic information on sensory-motor coordination.

Safety and efficacy of water pressure endoscopic submucosal dissection for colorectal tumors with submucosal fibrosis (with video).

BACKGROUND AND AIMS: Colorectal neoplasms with submucosal fibrosis are the most challenging targets of endoscopic resection. Water pressure endoscopic submucosal dissection (WP-ESD) is a recently introduced procedure that has several advantages over conventional endoscopic submucosal dissection (C-ESD). This study aimed to assess the efficacy and safety of WP-ESD for fibrotic colorectal neoplasms. METHODS: This retrospective observational study investigated 133 colorectal neoplasms expected to have submucosal fibrosis that were resected by WP-ESD or C-ESD between April 2012 and April 2020. Eighty-seven lesions after endoscopic or surgical treatment, 18 with biopsy scar with fold convergence and 28 in patients with ulcerative colitis, were included. The differences in treatment outcomes, including procedure time and adverse event proportions, between the WP-ESD and C-ESD groups were analyzed. The clinical course after perforation using WP-ESD was also evaluated, including postprocedural multidetector CT findings obtained immediately after WP-ESD. RESULTS: Severe submucosal fibrosis was observed in 96 lesions (72.2%). The median procedure time was significantly shorter in the WP-ESD group than in the C-ESD group (43.5 minutes [interquartile range {IQR}, 32.8-73] vs 72 minutes [IQR, 45-105]; P = .0041). The multivariate analysis revealed WP-ESD as an independent factor for a short procedure time (odds ratio, 2.90; 95% confidence interval, 1.28-6.55). The proportions of post-ESD electrocoagulation syndrome (11.6% vs 13.1%) and perforation (20.4% vs 22.8%) were similar between the groups. Four of 11 patients with perforation who underwent WP-ESD showed fluid collection on postprocedural multidetector CT images. CONCLUSIONS: WP-ESD can shorten procedure time for treating fibrotic colorectal neoplasms.

Evaluation Methods for the Measurement of Lower Leg Edema in Healthy Young Adults.

BACKGROUND: In recent years, objective quantitative evaluations have become particularly important. Both qualitative and quantitative evaluations are also available for edema. It is thought that the technical problem of quantitative evaluation can be solved by using a simple and reproducible method. Several studies have evaluated various methods for measuring edema. Limitations, such as weaknesses, measurement complexity, and errors, have been identified. Therefore, this study aimed to consider a simple and effective measurement method for the quantitative evaluation of edema. METHODS: This study was a prospective, observational study. The subjects were 15 healthy adults (2 male and 13 female). Measurements were performed on the subjects' right lower leg once in the morning and once in the afternoon, with a minimum interval of 4 hours. RESULTS: The actual volume of the lower leg was correlated with all indices except the ultrasonic echo findings for subcutaneous tissue. The intra-subject and inter-subject reliabilities for the indices using digital images were very high. The lower leg volume was greater significantly in the afternoon from the morning. CONCLUSION: The leg circumference was measured by utilizing a tape, while the width and volume were measured by utilizing digital imaging suitable for quantitatively evaluating edema. Furthermore, swelling of the lower leg with time can occur in the absence of daily exercise.

Sensory gating and suppression of subjective peripheral sensations during voluntary muscle contraction.

BACKGROUND: During voluntary muscle contraction, sensory information induced by electrostimulation of the nerves supplying the contracting muscle is inhibited and the somatosensory evoked potentials (SEPs) amplitude decreases. This depression of sensory input during voluntary muscle contraction has been demonstrated by many studies using electrophysiological methods. However, the association between the electrophysiological response of the sensory system during sustained muscle contraction and subjective peripheral sensation (SPS) is still unclear. The aim of this study was to investigate changes in spinal excitability, SEPs, and SPS during voluntary muscle contraction. RESULTS: The appearance rate of the F-wave was significantly higher during muscle contraction than rest, whereas no significant difference was observed in F-wave latency between muscle contraction and rest. Furthermore, the P25 amplitude of SEPs was significantly lower during muscle contraction than rest, whereas the N20 amplitude of SEPs exhibited no significant differences. The SPS was significantly lower during muscle contraction than rest CONCLUSIONS: We conclude that sensory gating, which is found in the P25 component of SEPs during muscle contraction, is one of the neurophysiological mechanisms underlying the suppression of SPS.

Effect of circulatory system response to motor control in one-sided contractions.

PURPOSE: The purpose of this study was to clarify the effect one-sided skeletal muscle contraction has on the circulatory system, spinal α-motoneuron excitability, and somatosensory-system-evoked potential. METHOD: Nine healthy males maintained tension at 10, 20, and 30% of maximal voluntary contraction in static gripping in right hand. Heart rate, ln high frequency (HF), blood pressure (BP), F-wave, and somatosensory-evoked potential (SEP) were recorded during gripping task. BP, F-wave and SEP were recorded from left hand (contralateral side from contracting side). RESULT AND CONCLUSION: There were significant main effects of contractions strength on heart rate (0%: 68.2 ± 6.8 bpm, 10%: 67.6 ± 7.4 bpm, 20%: 69.7 ± 8.5 bpm, 30%: 73.7 ± 9.3 bpm, F3.24=9.18, P < 0.01), systolic BP (0%: 127.7 ± 15 mmHg, 10%: 136.2 ± 13.5 mmHg, 20%: 136.2 ± 13.5 mmHg, 30%: 140.0 ± 17.1 mmHg, F3.24=23.93, P < 0.01), diastolic BP (0%: 69.3 ± 8.5 mmHg, 10%: 76.9 ± 11.1 mmHg, 20%: 79.9 ± 12.5 mmHg, 30%: 86.2 ± 14 mmHg, F3.24=17.09, P < 0.01), and F-wave appearance rate (0%: 29.7 ± 15.6%, 10%: 39.3 ± 20.5%, 20%: 47.5 ± 22.9%, 30%: 55.2 ± 21.8%, F3.24=14.04, P < 0.01). For the ln HF (0%: 5.9 ± 0.6, 10%: 6.3 ± 0.9, 20%: 6.3 ± 1.3, 30%: 6.0 ± 1.0, F3.24=2.43, P = 0.08), F-wave latency (0%: 29.6 ± 1.7 ms, 10%: 26.9 ± 2.1 ms, 20%: 26.5 ± 3.6 ms, 30%: 26.9 ± 2.3 ms, F3.24=0.11, P = 0.96), F-wave amplitude (0%: 2.0 ± 0.9%, 10%: 2.2 ± 0.9%, 20%: 2.3 ± 0.7%, 30%: 2.8 ± 1.1%, F3.24=2.80, P = 0.06), and N20 amplitude (0%: 3.9 ± 1.7 µV, 10%: 3.7 ± 1.7 µV, 20%: 3.9 ± 1.7 µV, 30%: 3.9 ± 1.8 µV, F3.24=0.61, P = 0.62), between the conditions. We conclude that regulation of the circulatory system and motor system has a limited effect on sensory input.

Effects of Low-Intensity Exercise in the Morning on Physiological Responses During Unsteady Workload Exercise in the Evening.

This study examined the effects of low-intensity morning exercise (ME) on physiological response during unsteady workload evening exercise. Nine healthy men participated in the following 2 experimental conditions: 15 minutes of bicycle exercise at 40% maximum oxygen consumption (V[Combining Dot Above]O2max) in the morning (the ME condition) and rest (control [C] condition). Heart rate (HR), blood pressure (BP), temperature, oxygen uptake, and natural logarithm of high frequency, an index of cardiac parasympathetic modulation, were measured before evening exercises, which were performed for 32 minutes in 2 parts: The steady-state exercise test included three 4-min bouts of exercise at 20, 60, and 40% V[Combining Dot Above]O2max. The unsteady exercise test consisted of 4-min bouts of exercise with gradual increases and decreases in workload at 20 and 60% V[Combining Dot Above]O2max. Heart rate, BP, and oxygen uptake were measured in both experiments. Maximal and minimal values, amplitude, and phase lags were measured with each cycle of unsteady workload exercise. With steady-state exercise, HR and systolic BP at 60 and 40% V[Combining Dot Above]O2max were significantly lower in the ME condition than in the C condition. However, oxygen uptake was not significantly different between the 2 conditions. With unsteady exercise, the HR and oxygen uptake phase lags were significantly shorter and the amplitude of oxygen intake was significantly larger in the ME condition than in the C condition. There were no significant differences in physiological parameters between the conditions at rest or during recovery. The physiological response during evening exercise is enhanced by low-intensity ME, which might be an effective conditioning method on a sporting event day.

Exhaustive exercise increases the TNF-α production in response to flagellin via the upregulation of toll-like receptor 5 in the large intestine in mice.

Although intense exercise may induce temporary immune depression, it is unclear whether exercise stimulates tumor necrosis factor-alpha (TNF-α) production in response to flagella protein flagellin (FG), which binds to toll-like receptor 5 (TLR5) and induces the production of pro-inflammatory cytokines. Male C3H/HeN mice were administered FG (1mg/kg, i.v.) after exhaustive exercise (EX), and the plasma TNF-α concentrations were examined. The production of TNF-α and the TLR5 expression in both RAW264 and Caco2 cells were measured under FG conditions in vitro. Although the plasma TNF-α concentrations were observed to significantly increase in both the EX and non-EX (N-EX) mice (p<0.01, respectively) following FG injection, the TNF-α levels in the EX mice were significantly higher than those observed in the N-EX mice (p<0.01). Epinephrine (Ep) treatment accelerated the FG-induced TNF-α production and TLR5 expression on the Caco2, but not RAW264 cells. Interestingly, a high Ep-induced TLR5 expression was observed on the Caco2 cell surface, which was inhibited by an inhibitor of phosphoinositide3-kinase (PI3K), Ly294002, as well as a ß-adrenergic blocker, propranolol. In addition, the EX-induced TNF-α production observed in response to FG was also attenuated by pretreatment with propranolol. Our findings suggest that exhaustive exercise upregulates the production of TNF-α in response to FG via a high expression of TLR5 on the intestinal cell surface following the stimulation of ß-adrenergic receptors with exercise.

Effects of Water Temperature during Foot Bath in Young Females.

We examined the effects of environmental and water temperatures of foot baths on pulse rate, blood pressure, mean skin temperature, salivary amylase (SA) activity, relaxation level and thermal sensation during winter. Five females participated in the study. The subjects rested in a chair for 20 min and the above-noted physiological reactions during the last 5 min of the resting period were recorded as baseline (BASE) values. Next, the subjects received a 15-min foot bath in water at 40 °C (WT40) or 45 °C (WT45), with a 15-min recovery period. Although SA is thought to be an indicator of stress via the sympathetic nervous system, we did not find a correlation between SA activity and relaxation state. We considered the possible effect of seasonal variation on the physiological reaction to foot bathing.

[Changes in core temperature during snow shoveling among healthy young males in heavy-snowfall area of Chugoku region in Japan].

OBJECTIVES: There are several recommendations on the prevention of hypothermia during snow shoveling. However, there seemed to be insufficient evidence supporting these recommendations because they are not based on data from actual snow shoveling research. The purpose of this study was to investigate changes in brain temperature (tympanic temperature) and visceral temperature (rectal temperature) during snow shoveling among healthy young males. METHODS: Eight healthy young males (age, 23.6 ± 2.4 years; weight, 69.7 ± 6.1 kg; height, 172.8 ± 7.3 cm) performed snow shoveling with an ordinary-size shovel for 15 min at their own pace in a rural snowfall area in December, 2009. Rectal temperature (Tre) and tympanic temperature (Tty) were measured 5 times (at rest, 5th (Ex5), 10th (Ex10), and 15th (Ex15) minute of snow shoveling; and 5th (Rec5) minute of recovery phase). The room temperature was 18.6 ± 0.7°C and the atmospheric temperature was 3.8 ± 2.6°C. RESULTS: Tre continued to increase from at rest to Ex15. Tre at Ex15 (37.7 ± 0.3°C) was significantly higher (p < 0.05) than that at rest (37.2 ± 0.3°C). Tty at rest (36.7 ± 0.2°C) and Tty at Ex5 (36.6 ± 0.3°C) decreased significantly (p < 0.05) at Ex10 (36.2 ± 0.6°C). A significant negative correlation between changes in Tre and Tty were observed during snow shoveling (r = -0.49, p < 0.05). CONCLUSION: Discrepancy between changes in brain temperature (tympanic temperature) and visceral temperature (rectal temperature) should be taken into consideration in the prevention of disease development during snow shoveling in a cold environment.

Attenuated increases in blood pressure by dynamic resistance exercise in middle-aged men.

The present study was performed to test the hypothesis that the blood pressure (BP) response to resistance exercise in middle-aged men with stiffening arteries is greater than that in young men with compliant arteries. The BP responses to acute dynamic resistance exercise (leg press) at individual relative (low, moderate and high) and absolute intensities were investigated in both young and middle-aged men. A total of 21 sedentary healthy normotensive men, 21-25 years of age (young) and 41-59 years of age (middle-aged), were included in the study. At rest, the arterial compliance (simultaneous ultrasound and applanation tonometry) and muscle strength (leg press) were lower, and indices of arterial stiffness and BP were higher in the middle-aged men than in the young men (p < 0.05). There were no significant differences in height, body mass, or heart rate between the two groups. During exercise, the systolic BP of the middle-aged men at 80% one-repetition maximum (1RM) was significantly lower than that of the young men for the last half of the exercise period (p < 0.05). The amounts of change in systolic and diastolic BP from baseline to the end of resistance exercise were lower in the middle-aged men than in the young men at individual relative intensities (p < 0.05) and at individual absolute intensity. In contrast to our hypothesis, these findings indicated that the BP response during dynamic resistance exercise using large muscle groups may be attenuated in middle-aged men relative to young men.

Variations in carotid arterial compliance during the menstrual cycle in young women.

The effect of menstrual cycle phase on arterial elasticity is controversial. In 10 healthy women (20.6+/-1.5 years old, mean+/-s.d.), we investigated the variations in central and peripheral arterial elasticity, blood pressure (carotid and brachial), carotid intima-media thickness (IMT), and serum oestradiol and progesterone concentrations at five points in the menstrual cycle (menstrual, M; follicular, F; ovulatory, O; early luteal, EL; and late luteal, LL). Carotid arterial compliance (simultaneous ultrasound and applanation tonometry) varied cyclically, with significant increases from the values seen in M (0.164+/-0.036 mm2 mmHg-1) and F (0.171+/-0.029 mm2 mmHg-1) to that seen in the O phase (0.184+/-0.029 mm2 mmHg-1). Sharp declines were observed in the EL (0.150+/-0.033 mm2 mmHg-1) and LL phases (0.147+/-0.026 mm2 mmHg-1; F=8.51, P<0.05). Pulse wave velocity in the leg (i.e. peripheral arterial stiffness) did not exhibit any significant changes. Fluctuations in carotid arterial elasticity correlated with the balance between oestradiol and progesterone concentrations. No significant changes were found in carotid and brachial blood pressures, carotid artery lumen diameter, or IMT throughout the menstrual cycle. These data provide evidence that the elastic properties of central, but not peripheral, arteries fluctuate significantly with the phases of the menstrual cycle.

Side-to-side differences in cortical bone mineral density of tibiae in young male athletes.

The importance of physical activity in the development and maintenance of bone mineral density (BMD) is widely accepted. However, the effects on cortical BMD have not been clarified in detail. The present study examined bilateral asymmetries in cortical BMD of the tibia using peripheral quantitative computed tomography. Subjects comprised 37 young male athletes and 57 controls (age range, 18-28 years). BMD and geometrical indices were determined in bilateral tibiae. Cortical and trabecular BMD were calculated at the diaphysis and distal metaphysis, respectively. Cortical width, periosteal cross-sectional area, and cross-sectional moment of inertia were calculated using tomographic data of the tibial diaphysis. In athletes, the non-dominant leg showed greater cortical BMD than the dominant leg (mean difference, 5.42%; P < 0.0001). Cortical width and moment of inertia were also greater in the non-dominant leg. Periosteal area displayed no significant difference between legs. The control group exhibited similar results except for cortical BMD. No differences in trabecular BMD were noted between legs in either athletes or controls. These results implies the existence of mechanisms for the mechanical adaptation of cortical BMD. Dominant leg is used for mobility or manipulation whereas the non-dominant leg contributes to support the actions of the dominant leg. Loading differences in bilateral legs in young athletes might affect the remodeling rate leading to the side-to-side differences in cortical BMD.