Increase In Muscle Thickness Research Articles

MON-479 Gross and Microscopic Intestinal Morphology of Bovine Growth Hormone Transgenic Mice Longitudinally

Growth hormone (GH) has been shown to have important effects on the intestines, demonstrated by its use in treatment of short bowel syndrome and the increase in colon polyps seen in acromegaly. Accordingly, GH has been shown to affect intestinal morphology at the gross and microscopic levels, including increased intestinal length and increased villus height in situations of excess GH aged 2 months. However, the effect of excess GH on intestinal morphology longitudinally or at advanced ages has not been extensively examined. This study measured the gross and microscopic intestinal morphology at multiple ages in bovine GH (bGH) transgenic mice, a mouse model of acromegaly. Adult bGH mice and littermate controls aged 6, 11, or 13 months were used for this study. The intestines were dissected, mesenteric fat was removed, and the small intestine (SI) was separated from the large intestine (LI). The length and circumference of the SI and the LI were measured. Intestinal portions were processed using the Swiss roll method, paraffin embedded, sectioned, and stained. The images of the sections were then used to measure the villus height, crypt depth and muscle thickness. In accordance with previous reports in humans and mice, chronic GH excess causes increased intestinal length. This difference was present in both the SI and LI and at 6, 11, and 13 months of age. bGH mice at all three ages had increased SI weight. LI weight was increased in bGH mice at 6 and 13 months of age, but there was no increase at 11 months of age. At 13 months of age, the LI circumference was increased in bGH mice, and the SI circumference at 6 months of age was also increased. At the microscopic level, the 6-month-old bGH mice had significantly increased crypt depth in the duodenum and jejunum, and a trend in the ileum. There is also a trend towards increased villus height in the 6-month bGH mice in all three sections of the SI that did not reach significance. The only change observed in the 11-month bGH mice was increased muscle thickness in the duodenum. The results of this study indicate that chronic GH excess indeed increases intestinal length, a change that persists longitudinally. The previously reported increase in intestinal villus height in response to GH excess was not observed in this experiment, but increased crypt depth was observed in the youngest cohort. The oldest group had an increase in SI circumference that coincided with increased muscle thickness in the 11-month bGH mice. In summary, our data show a potent trophic effect of GH on the intestinal tract, as well as an effect on the microscopic morphology of the intestines; however, the microscopic changes differ from those previously reported and do not seem to persist over the lifespan of a mouse. Acknowledgements: This work was supported by the State of Ohio’s Eminent Scholar Program that includes a gift from Milton and Lawrence Goll, by AMVETS, and by the Diabetes Institute at Ohio University

Bouncing Back! Counteracting Muscle Aging With Plyometric Muscle Loading.

The preservation of muscle power is crucial in aging for maintaining mobility and performing daily tasks. Resistance training involving high movement velocities represents a valid strategy to slow down the rate of sarcopenia, counteracting the loss of muscle mass and muscle power. Plyometric exercise may represent an effective training modality for increasing muscle power; however, its application in older populations has been sparingly investigated, as the high impact actions involved may reduce its feasibility for older individuals. By adopting a safer modality of plyometric training, we investigated if a 6-week plyometric training intervention could increase knee extensor muscle size, architecture, force and power in 14 young (YM, age = 25.4 ± 3.5 y; means ± SD) and nine older males (OM, age = 69.7 ± 3.4 y). Volunteers trained 3 times/week using a device similar to a leg press machine where the user was required to bounce against his body mass on a trampoline. Pre-to-post training changes in isometric maximum voluntary torque (MVT), leg extension power and vastus lateralis (VL) architecture were assessed. Muscle power increased in both groups (+27% OM -P < 0.001, 20% YM -P < 0.001), although the total external work performed during the training period was significantly lower for OM (i.e., ~-47%). Both groups showed significant increases in muscle thickness (MT) (+5.8 OM -P < 0.01 vs. +3.8% YM -P < 0.01), fascicle length (Lf) (+8% OM -P < 0.001 vs. +6% YM -P < 0.001), and pennation angle (PA) (+7.5% OM -P < 0.001 vs. +4.1% YM -P < 0.001). The current study shows that trampoline-based plyometric training is an effective intervention producing a rapid increase in muscle mass and power in both young and older individuals. The training modality used in this study seems to particularly benefit the older population, targeting the morphological and functional effects of sarcopenia in human muscle.

The effect of a portable electrical muscle stimulation device at home on muscle strength and activation patterns in locomotive syndrome patients: A randomized control trial

The aim of the present study was to quantify the effect of electrical muscle stimulation (EMS) intervention using a portable device on muscle strength and activation patterns in locomotive syndrome. Nineteen women were randomly assigned to the intervention group (n = 10; age = 71–82 years) and control group (n = 9; age = 70–84 years). Participants in the intervention group used a portable EMS device to stimulate the bilateral quadriceps muscles for 8 weeks (23 min/5 days/week). To understand the effects of EMS, the following measurements were made at baseline, 8 weeks, and 12 weeks: locomotive syndrome assessment score, knee extensor strength, vastus lateralis muscle activation patterns during a maximal isometric knee extension contraction using multi-channel surface electromyography, and muscle thickness. The locomotive syndrome assessment, muscle strength, muscle thickness, and muscle activity patterns in the intervention group were significantly different to control after 8 weeks (p < 0.05). However, these results were not sustained at 12 weeks. EMS increased locomotor assessment scores, which were accompanied by enhanced muscle strength, increased muscle thickness, and changes in muscle activation patterns in locomotive syndrome patients. These results suggest that EMS is potentially useful for improving muscle neural activation and force output in locomotive syndrome.

Passive and dynamic muscle architecture during transverse loading for gastrocnemius medialis in man

External forces from our environment impose transverse loads on our muscles. Studies in rats have shown that transverse loads result in a decrease in the longitudinal muscle force. Changes in muscle architecture during contraction may contribute to the observed force decrease. The aim of this study was to quantify changes in pennation angle, fascicle dimensions, and muscle thickness during contraction under external transverse load.Electrical stimuli were elicited to evoke maximal force twitches in the right calf muscles of humans. Trials were conducted with transverse loads of 2, 4.5, and 10 kg. An ultrasound probe was placed on the medial gastrocnemius in line with the transverse load to quantify muscle characteristics during muscle twitches.Maximum twitch force decreased with increased transverse muscle loading. The 2, 4.5, and 10 kg of transverse load showed a 9, 13, and 16% decrease in longitudinal force, respectively. Within the field of view of the ultrasound images, and thus directly beneath the external load, loading of the muscle resulted in a decrease in the muscle thickness and pennation angle, with higher loads causing greater decreases. During twitches the muscle transiently increased in thickness and pennation angle, as did fascicle thickness. Higher transverse loads showed a reduced increase in muscle thickness. Smaller increases in pennation angle and fascicle thickness strain also occurred with higher transverse loads.This study shows that increased transverse loading caused a decrease in ankle moment, muscle thickness, and pennation angle, as well as transverse deformation of the fascicles.

Comparing the effects of low and high load resistance exercise to failure on adaptive responses to resistance exercise in young women

ABSTRACTThe aim of this study was to compare the effect of 6 weeks of resistance training to volitional failure at low (30% 1 repetition maximum (RM)) or high (80%1RM) loads on gains in muscle size and strength in young women. Thirteen women (age: 29.7 ± 4.7years; height 166.7 ± 6.4cm; weight 64.2 ± 12.2kg) completed 2 training sessions per week for 6 weeks and muscle strength (1RM), muscle thickness (ultrasound) were measured before and after training. Training comprised 1 set to volitional failure of unilateral leg extensions and bicep curls with each limb randomly assigned to train at either 80% 1RM or 30% 1RM. Increases in muscle thickness [arms: 6.81 ± 3.15% (30% 1RM), 5.90 ± 3.13% (80% 1RM) and legs: 9.37 ± 5.61% (30% 1RM), 9.13 ± 7.9% (80% 1RM)] and strength [arms: 15.4 ± 12.2% (30% 1RM), 18.26 ± 12.2% (80% 1RM) and legs: 25.30 ± 18.4 (30% 1RM), 27.20 ± 14.5 (80% 1RM)] were not different between loads. When resistance exercise is performed to volitional failure gains in muscle size and strength are independent of load in young women.

Isokinetic resistance training combined with eccentric overload improves athletic performance and induces muscle hypertrophy in young ice hockey players

ObjectivesTo determine the combined effects of slow isokinetic resistance training and eccentric overload and compare it to traditional resistance training on strength, power, body composition and muscle hypertrophy in young ice hockey players. DesignExperimental, randomized trial. MethodsTwenty-two resistance-trained ice hockey players (18±1year) were assigned to either isokinetic resistance training and eccentric overload (ISO/ECC; n=11) or traditional resistance training (TRAD; n=11). Participants underwent supervised progressive resistance training for 8 weeks (2–3 sessions/week) involving lower body multiple-joint exercises (heavy squats and explosive jump squats). The ISO/ECC group performed their training using a computerized robotic engine system (1080 Quantum synchro, Sweden), whereas the TRAD group performed the same resistance exercises with isotonic loading. Before and after the intervention, participants were evaluated in 1RM back squat, loaded jump squats, sprint- and jump performance, body composition and muscle thickness using ultrasound measurement. ResultsSimilar moderate increases in 1RM back squat and power output in the jump squats were found in both the ISO/ECC and TRAD groups (11–17%, P<0.01), whereas only the ISO/ECC group showed improvements in drop jump performance (9.8%, P=0.01). Moreover, similar trivial changes in body composition were observed in both groups, while only the ISO/ECC training group increased muscle thickness in the vastus intermedius (P=0.01) and rectus femoris muscles (P=0.03). ConclusionsBoth modalities effectively increased maximal strength and power output, whereas isokinetic resistance training, combined with eccentric overload, improved drop jump performance and induced greater muscle hypertrophy than traditional training in young ice hockey players.

The influence of fixation on the cardiac tissue in a 1-year observation of swine hearts.

The aim of this study was to investigate the influence of formaldehyde-based fixation on dimension, weight and shape of cardiac tissue during a 1-year observation. Seven measuring sites were permanently marked in 40 swine hearts prior to fixation. Four study groups (n=10 each) were assembled that differed only in concentration and the type of fixative. The fixatives were 2%, 4% or 10% formaldehyde phosphate-buffered solution (FPBS) and alcoholic formalin. The samples were measured before fixation and then after fixation at 1week, 3, 6 and 12months. At the 3-month point, the 10% FPBS had caused significant changes in the smallest number of parameters, while the 2% FPBS affected the greatest number of dimensions. The most significant changes included chordae tendineae shrinkage and an increase in muscle thickness. After 6months, the most significant changes were observed in 2% and 4% FPBSs and were also mainly associated with an increase in muscle thickness and chordae tendineae shrinkage. 1-year preservation compared to the baseline showed the most significant changes in muscle tissue thickness and hearth weight. The artery diameter decreased in long-term fixation in every tested solution. For atrial and angle measurements, 4% FPBS caused most significant changes among investigated fixatives. In all tested solutions, long-term fixation significantly changed cardiac tissue dimension compared to the nonpreserved samples. Short-term to 1-year fixation changes are smaller, but they should not be neglected. Different fixatives should be used depending on the character of the planned measurements.

Cholecystokinin induces esophageal longitudinal muscle contraction and transient lower esophageal sphincter relaxation in healthy humans.

Cholecystokinin (CCK) is known to cause lower esophageal sphincter (LES) relaxation through the activation of inhibitory motor neurons. CCK receptor agonists increase the frequency of transient LES relaxation through a peripheral mechanism. Recent studies show that the longitudinal muscle contraction (LMC)-related axial stretch might play a role in the LES relaxation by activating the mechanosensitive inhibitory motor neurons. The aim of our study was to determine whether the CCK-induced LES relaxation and the characteristics of LMC resemble those seen with spontaneous transient LES relaxation in humans. Nine healthy volunteers (5 Fr, 40 ± 12 yr) received escalating doses of CCK-octapeptide (CCK-8) (5, 10, 20, and 40 ng/kg). All subjects demonstrated a monophasic response to 5 ng/kg of CCK-8. In the majority of subjects, this response consisted of partial LES relaxation. All subjects showed a biphasic response to 40 ng/kg of CCK-8. The latter in most subjects consisted of 1) a period of partial relaxation followed by 2) complete LES relaxation along with crural diaphragm inhibition. The length of the esophagus decreased by 0.9 ± 0.4 cm, and muscle thickness increased by 40 ± 14% to 1.4 ± 0.2 mm ( P < 0.05) during initial partial LES relaxation. During complete LES relaxation there was greater LMC, as demonstrated by an esophageal shortening of 1.9 ± 0.5 cm and an increase in muscle thickness of 100 ± 16% ( P < 0.01). The complete phase 2 LES relaxation typically terminated with a robust after-contraction. Atropine significantly attenuated the CCK-induced esophageal LMC, prevented crural diaphragm inhibition, and abolished the phase 2 complete LES relaxation. NEW & NOTEWORTHY The phenotypic features of CCK-induced longitudinal muscle contraction (LMC), complete lower esophageal sphincter (LES) relaxation, and crural diaphragm inhibition, followed by a robust after-contraction, resemble those seen during spontaneous transient LES relaxation. A strong temporal relationship between the LMC and complete transient LES relaxation supports our hypothesis that the LMC plays an important role in the LES relaxation and crural diaphragmatic inhibition.

Genesis of Esophageal Pressurization and Bolus Flow Patterns in Patients With Achalasia Esophagus

In patients with achalasia esophagus, swallows induce simultaneous pressure waves known as esophageal pressurization. We studied the mechanism of esophageal pressurization and bolus flow patterns in patients with type 2 or type 3 achalasia. We recorded high-resolution manometry with impedance and intraluminal ultrasound images concurrently in patients with type 2 achalasia (n= 6) or type 3 achalasia (n= 8) and in 10 healthy subjects (controls) during swallows of 5 mL of 0.5N saline. For each swallow, the ultrasound image was aligned with the pressure and impedance tracings to determine cavity and contact pressure, bolus arrival, bolus dwell time, and changes in muscle thickness at 5 cm and 10 cm above the lower esophageal sphincter. In patients with type 2 achalasia, esophageal pressurization was associated with an increase in the muscle thickness and luminal narrowing but not complete luminal closure (ie, cavity pressure). Bolus arrival time in the distal esophagus after the onset of a swallow was delayed in patients with type 3 achalasia compared with control individuals because of early luminal closure. The early luminal closure was associated with a decrease in the muscle thickness. The bolus dwell time was shorter in patients with type 3 achalasia compared with control individuals. In patients with type 3 achalasia, the onset of simultaneous pressure wave was always a cavity pressure, but during contraction there were different periods of cavity and contact pressures in association with increases in muscle thickness that resulted in bolus segmentation. We observed distinct mechanisms of esophageal pressurization and bolus flow patterns in patients with type 2 or type 3 achalasia esophagus compared with control individuals. These findings will increase our understanding of the mechanisms of dysphagia.

Effects of an acute bout of dynamic stretching on biomechanical properties of the gastrocnemius muscle determined by shear wave elastography.

AimsThe aim of this study was to examine the acute effects of dynamic stretching (DS) exercise on passive ankle range of motion (RoM), resting localized muscle stiffness, as measured by shear wave speed (SWS) of medial gastrocnemius muscle, fascicle strain, and thickness.Methods/ResultsTwenty-three participants performed a DS protocol. Before and after stretching, SWS was measured in the belly of the resting medial gastrocnemius muscle (MGM) using shear wave elastography. DS produced small improvements in maximum dorsiflexion (+1.5° ±1.5; mean difference ±90% confidence limits) and maximum plantarflexion (+2.3° ±1.8), a small decrease in fascicle strain (-2.6% ±4.4) and a small increase in SWS at neutral resting angle (+11.4% ±1.5). There was also a small increase in muscle thickness (+4.1mm ±2.0).ConclusionsThrough the use of elastography, this is the first study to suggest that DS increases muscle stiffness, decreases fascicle strain and increases muscle thickness as a result of improved RoM. These results can be beneficial to coaches, exercise and clinical scientists when choosing DS as a muscle conditioning or rehabilitation intervention.

Chemopreventive Effect of Aster glehni on Inflammation-Induced Colorectal Carcinogenesis in Mice.

Although Aster glehni is a common dietary herb that has various bioactivities, including anti-diabetic, anti-adipogenic, and anti-inflammatory effects, A. glehni has not been studied in colon cancer. Therefore, we hypothesized the chemopreventive effects of an ethanol extract of A. glehni (AG) on azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colitis-associated cancer (CAC) in mice. In this study, we found that treatment with AG significantly attenuated the AOM/DSS-induced enlargement of the spleen and shortening of the colon. In addition, colonic tumor formation, colonic damage, and increased muscle thickness were significantly reduced in AOM/DSS-induced mice fed AG. Treatment with AG also reduced intestinal interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α production and decreased inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein expression in mice with AOM/DSS-induced CAC. Furthermore, AG reduced nuclear factor (NF)-κB activation via phosphorylation and degradation of inhibitor of kappa Bα (IκBα), leading to inhibition of NF-κB p65 nuclear translocation. It also downregulated the expression of NF-κB-related proteins, including the B-cell lymphoma 2 (Bcl-2) family and inhibitors of apoptosis proteins (IAPs), in mice with AOM/DSS-induced CAC. Taken together, these findings suggest that the treatment with AG inhibited colitis-associated colon carcinogenesis in mice, and this chemopreventive effect was strongly mediated by suppression of the NF-κB signaling pathway, indicating that AG could be a promising protective agent against CAC.

Changes in thickness of the transversus abdominis during the abdominal drawing-in manoeuvre and expiratory muscle training in elderly people.

[Purpose] It has been reported that exercises focusing upon the transversus abdominis (TrA) ameliorate low back pain (LBP). We investigated whether expiratory muscle training (EMT) can promote activity of the TrA to the same degree as the abdominal drawing-in manoeuvre (ADIM) in elderly individuals. [Subjects and Methods] Twenty-one elderly subjects (9 males, 12 females; mean age, 84.9 ± 6.6 years) without LBP symptoms were included. Using ultrasound imaging we measured changes in thickness of the lateral abdominal muscles, TrA, internal oblique muscle (IO), and external oblique muscle (EO) during ADIM and EMT. The load in EMT was set to 15% of maximal expiratory pressure. [Results] TrA showed a significant increase in muscle thickness during ADIM and EMT compared with at rest. A significant increase in muscle thickness was noted for EMT in comparison with ADIM. No significant differences were found for IO and EO. [Conclusion] In elderly people, EMT may be an effective alternative to ADIM for promoting activity of the TrA and can be used as an exercise to maintain TrA function.

Effects of dietary dandelion extract on intestinal morphology, antioxidant status, immune function and physical barrier function of juvenile golden pompano Trachinotus ovatus

Intestinal morphology, antioxidant status, immune function and tight junction proteins mRNA expression were examined in golden pompano (Trachinotus ovatus) that fed respectively six diets containing dandelion extracts (DE) at 0, 0.5, 1, 2, 4 and 10 g kg−1 after 8 weeks feeding. The study indicated that dietary DE significantly improved intestinal antioxidant abilities by increasing SOD, CAT, T-AOC activities and up-regulating intestinal cat, gpx mRNA levels, but by decreasing MDA content and down-regulating intestinal keap1 mRNA levels in golden pompano. Meanwhile, dietary DE improved intestinal morphology, suggesting that enhances intestinal digestion and absorption, by increasing muscle thickness, villus length, villus width and villus number in the foregut and hindgut; as well as villus number, villus width and muscle thickness in the midgut (P < .05). Dietary DE enhanced intestinal barrier function by increasing intestinal zo-1 and occludin mRNA levels, but by decreasing the mRNA levels of claudin-12 and claudin-15. Furthermore, dietary DE improved intestinal immunity via increasing goblet cells numbers and regulating expression of immune-related genes. In conclusion, dietary DE supplementation promoted intestine health by improving intestine morphology, immunity, antioxidant abilities and intestinal barrier in golden pompano.

The effects of supramaximal versus submaximal intensity eccentric training when performed until volitional fatigue.

Our purpose was to compare supramaximal versus submaximal intensity eccentric training performed until volitional fatigue. Thirty-two young adults (19 males) were randomized into one of three groups: (1) ECC110 performed eccentric (ECC) only contractions at 110% of concentric (CON) 1-repetition maximum (1RM); (2) ECC80 performed ECC only contractions at 80% of CON 1RM; (3) a control group. Training progressed from 3 to 6 sets of unilateral ECC training of the elbow flexors over 8weeks, with each set performed until volitional fatigue. Elbow flexors muscle thickness (via ultrasound) and 1RM were assessed pre- and post-training. Rating of perceived exertion (RPE) and muscle soreness was self-reported. Both ECC110 (+0.25cm) and ECC80 (+0.21cm) showed a greater post-training increase in muscle thickness compared to control (-0.01cm) (p<0.05), with no differences between ECC110 and ECC80. ECC80 (+1.23kg) showed a greater post-training increase in strength compared to control (p<0.05), while ECC110 (+0.76kg) had no significant difference post-training vs. control (-0.01kg). ECC80 had significantly lower average RPE scores than ECC110 (p<0.05). Both supramaximal intensity eccentric training and submaximal intensity eccentric training are effective for increasing muscle size, but submaximal eccentric training is perceived to require less exertion than supramaximal training. These findings suggest that submaximal eccentric training may be an ideal strategy to increase muscle size and strength in individuals whose needs warrant training at a lower level of exertion.

Greater Neural Adaptations following High- vs. Low-Load Resistance Training.

We examined the neuromuscular adaptations following 3 and 6 weeks of 80 vs. 30% one repetition maximum (1RM) resistance training to failure in the leg extensors. Twenty-six men (age = 23.1 ± 4.7 years) were randomly assigned to a high- (80% 1RM; n = 13) or low-load (30% 1RM; n = 13) resistance training group and completed leg extension resistance training to failure 3 times per week for 6 weeks. Testing was completed at baseline, 3, and 6 weeks of training. During each testing session, ultrasound muscle thickness and echo intensity, 1RM strength, maximal voluntary isometric contraction (MVIC) strength, and contractile properties of the quadriceps femoris were measured. Percent voluntary activation (VA) and electromyographic (EMG) amplitude were measured during MVIC, and during randomly ordered isometric step muscle actions at 10–100% of baseline MVIC. There were similar increases in muscle thickness from Baseline to Week 3 and 6 in the 80 and 30% 1RM groups. However, both 1RM and MVIC strength increased from Baseline to Week 3 and 6 to a greater degree in the 80% than 30% 1RM group. VA during MVIC was also greater in the 80 vs. 30% 1RM group at Week 6, and only training at 80% 1RM elicited a significant increase in EMG amplitude during MVIC. The peak twitch torque to MVIC ratio was also significantly reduced in the 80%, but not 30% 1RM group, at Week 3 and 6. Finally, VA and EMG amplitude were reduced during submaximal torque production as a result of training at 80% 1RM, but not 30% 1RM. Despite eliciting similar hypertrophy, 80% 1RM improved muscle strength more than 30% 1RM, and was accompanied by increases in VA and EMG amplitude during maximal force production. Furthermore, training at 80% 1RM resulted in a decreased neural cost to produce the same relative submaximal torques after training, whereas training at 30% 1RM did not. Therefore, our data suggest that high-load training results in greater neural adaptations that may explain the disparate increases in muscle strength despite similar hypertrophy following high- and low-load training programs.

Clinical topographical anatomy of the gastro-oesophageal junction in the cat.

Objectives The purpose of the present study was to describe histologically the gastro-oesophageal junction in the cat and interrelationships of this region. Our hypothesis was that cats are devoid of abdominal oesophagus. Methods Three centimetres of the terminal oesophagus, the phreno-oesophageal membrane with 1-2 cm margins of the diaphragmatic crural muscle and the proximal 3 cm of the gastric cardia were obtained from nine domestic shorthair cats and one domestic longhair cat that were euthanased for reasons other than digestive tract pathology. Longitudinal samples were examined histologically. Evaluated parameters included the location of the phreno-oesophageal membrane with reference to the transition between the oesophageal and gastric mucosa, the thickness of the circumferential smooth muscle of the muscular layer of the distal oesophagus at points 3 mm and 6 mm cranial to the mucosa transition, and the thickness of the circumferential smooth muscle layer at the mucosa transition level. Median differences in the thickness of the smooth muscle layer were compared by performing non-parametric statistical analysis using the Mann-Whitney U-test. Results The transition of the oesophageal to gastric mucosa was abrupt and corresponded to the point of insertion of the phreno-oesophageal membrane at the diaphragm level in all cats. The mean thickness of the circumferential smooth muscle layer at the point of oesophageal to gastric mucosa transition was significantly greater than the mean thickness of the oesophageal circumferential smooth muscle layer at 3 mm and 6 mm cranial to the mucosa transition ( P ⩽0.05). The increased muscle thickness at the gastro-oesophageal junction correlates with the accepted location of the high-pressure zone, reflecting the caudal oesophageal sphincter. It seems that the whole oesophagus was situated within the thoracic rather than the abdominal cavity. Conclusions and relevance No distinct abdominal oesophagus was observed in nine domestic shorthair cats and one domestic longhair cat. These findings might have implications for the pathophysiology of hiatal hernia in cats.

Decrease of Muscle Performance After Two Different Load Protocols in Well-Trained Men

To study muscle damage recovery, firstly muscle damage has to be induced by an exercise. A specific drop jumps protocol has been largely used in previous studies. However, all participants studied were untrained. PURPOSE: To assess muscle strength, muscle power and muscle swelling after two different load drop jump protocols in well-trained athletes. METHODS: Eighteen strength and/or power-trained male athletes (4.31±2.75 years of training experience) were randomly assigned into one of two groups. DJ100 consisted in 5 sets of 20 drop jumps from a 60-cm box with 2-minute rest interval (n=9, 23.00±2.74 years). DJ140 consisted in seven sets of 20 drop jumps also (n=9, 22.89±3.37 years). Volunteers performed a maximally explosive vertical jump. Both groups performed the assessment of indirectly markers of muscle damage before and immediately after exercise protocol. Muscle thickness of knee extensors was measured using B-mode ultrasound. Maximal isometric muscle strength (PT) was measured by 2 sets of 4 seconds maximal isometric knee extension at 60°. For vertical jump, the athletes performed three countermovement jumps as high as possible, with one-minute rest between jumps. After normal distribution confirmed by Shapiro-Wilk tests, independent samples T-tests were used to compare the magnitude of changes of muscle thickness, isometric strength and vertical jump between groups. A p-value of ≤ 0.05 was adopted. RESULTS: There was no significant difference (p>0.05) in sample’s baseline characteristics between groups. There was no significant difference in the increase of muscle thickness (DJ100: 6.47 ± 1.67 (16.50%) vs. DJ140: 7.51 ± 2.31 mm (17.82%); p = 0.286). The decrease of isometric strength was significantly greater in DJ140 than DJ100 (DJ100: 34.24 ± 22.30 (11.20%) vs. DJ140: 67.06 ± 38.79 N.m (22.41%); p = 0.043; ES = 1.037). The decrease of vertical jump was also significantly greater in DJ140 than in DJ100 (DJ100: 0.48 ± 2.88 (0.95%) vs. DJ140: 7.72 ± 7.44 cm (17.42%); p = 0.015; ES = 1.283). CONCLUSIONS: The main finding of this study was that an exercise protocol composed by 100 drop jumps did not decrease lower limb muscle power in well-trained athletes. Furthermore, 140 drop jumps induced a decrease in muscle performance greater than 100 drop jumps in well-trained athletes.

Catheter‐based high‐frequency intraluminal ultrasound imaging is a powerful tool to study esophageal dysmotility patients

High-resolution manometry (HRM) is currently the most important diagnostic test for esophageal motility disorders, providing information on the contraction pattern of the circular muscle layer, which helps classify these esophageal motor diseases. However, with the increasing development of ultrasound, other techniques, such as high-frequency intraluminal ultrasound (HFIUS), have gained importance. This technique uses a flexible shaft with a central wire integrated into a standard endoscope, which facilitates real-time sonography. Its main utility is to provide anatomical information on the structure of the esophageal wall, including both the circular and longitudinal layers that constitute the esophageal muscularis propria. Increasing knowledge about these motility disorders has led to the hypothesis that, in addition to an abnormal contraction pattern of the circular muscle, an overall increased muscle thickness and an abnormal longitudinal muscle contraction could be added as pathophysiological factors. The increase in muscle thickness could be an important indicator of the severity of diseases, such as achalasia, distal esophageal spasm, or hypercontractile esophagus. More studies are required before definitive conclusions can be reached, but HFIUS employed simultaneously with HRM could provide a more complete and precise evaluation of these esophageal motor disorders.

Stretch training induces unequal adaptation in muscle fascicles and thickness in medial and lateral gastrocnemii.

This study compared adaptations in fascicle lengths, pennation angles, and muscle thickness of the lateral and medial gastrocnemii in response to 6weeks of stretch training. The nondominant plantar flexors of 11 males were stretched five times per week for 6weeks and compared with the contralateral leg and a nonstretched control group of 10 males. During stretch training, instantaneous electromyography was utilized to ensure passive muscle stretch. At baseline, week three, week six and 1week after the conclusion of stretch training, ultrasound was used to measure fascicle lengths, pennation angles, muscle thickness of the lateral gastrocnemius and medial gastrocnemius, and Achilles tendon thickness and length. Plantar flexion torque was measured, and voluntary activation was assessed. Muscle thickness increased 5.6% after 6weeks of stretch training (P=.009). The fascicles in the lateral gastrocnemius lengthened to a greater extent than the medial. Overall, fascicles lengthened 25% (P<.001) in the muscle tendon junction and 5.1% (P<.001) in the muscle belly. Pennation angles were unchanged in the medial gastrocnemius but decreased in the lateral gastrocnemius 7.1% (P=.02). There was no change in maximal voluntary contraction, voluntary activation, tendon length, or thickness. This study demonstrates that stretch training is a viable modality to alter muscle architecture of the human gastrocnemius through lengthening of muscle fascicles, decreasing pennation angles, and increasing muscle thickness, albeit adaptations are unequal between the lateral and medial heads.

Targeted Genome Engineering to Control VEGF Expression in Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells: Potential Implications for the Treatment of Myocardial Infarction.

Human umbilical cord blood‐derived mesenchymal stem cells (hUCB‐MSCs) exhibit potency for the regeneration of infarcted hearts. Vascular endothelial growth factor (VEGF) is capable of inducing angiogenesis and can boost stem cell‐based therapeutic effects. However, high levels of VEGF can cause abnormal blood vessel growth and hemangiomas. Thus, a controllable system to induce therapeutic levels of VEGF is required for cell therapy. We generated an inducible VEGF‐secreting stem cell (VEGF/hUCB‐MSC) that controls the expression of VEGF and tested the therapeutic efficacy in rat myocardial infarction (MI) model to apply functional stem cells to MI. To introduce the inducible VEGF gene cassette into a safe harbor site of the hUCB‐MSC chromosome, the transcription activator‐like effector nucleases system was used. After confirming the integration of the cassette into the locus, VEGF secretion in physiological concentration from VEGF/hUCB‐MSCs after doxycycline (Dox) induction was proved in conditioned media. VEGF secretion was detected in mice implanted with VEGF/hUCB‐MSCs grown via a cell sheet system. Vessel formation was induced in mice transplanted with Matrigel containing VEGF/hUCB‐MSCs treated with Dox. Moreover, seeding of the VEGF/hUCB‐MSCs onto the cardiac patch significantly improved the left ventricle ejection fraction and fractional shortening in a rat MI model upon VEGF induction. Induced VEGF/hUCB‐MSC patches significantly decreased the MI size and fibrosis and increased muscle thickness, suggesting improved survival of cardiomyocytes and protection from MI damage. These results suggest that our inducible VEGF‐secreting stem cell system is an effective therapeutic approach for the treatment of MI. Stem Cells Translational Medicine 2017;6:1040–1051