The Components of Lumbar Motor Control Are Not Inter-related.

OBJECTIVES: To verify the relationship between the indicators of components of lumbar motor control and determine the factors related to the indicators to each of these components. METHODS: Twenty-five healthy university students were included in the study. The lumbar spine and hip kinematic parameters of posterior/anterior pelvic tilt (mobility and smoothness), ball catching (reactivity), and forward/backward rocking (adaptive stability) were measured as indicators of lumbar motor control. Lumbar proprioception, trunk muscle strength, and lower trunk muscle thickness were also measured. Kinematic parameters of the lumbar spine and hip were measured using a small accelerometer. The data verified the relevance of indicators of lumbar motor control and the relationship with relevant factors. RESULTS: No significant correlations were found for most lumbar motor control indicators. Lumbar proprioception and rectus abdominis muscle thickness were identified as relevant indicators of lumbar motor control. CONCLUSIONS: Each component of lumbar motor control is independent and must be evaluated for the component whose function is required. Additionally, some components of lumbar motor control are associated with lumbar proprioception and rectus abdominis muscle thickness; thus, evaluation of these components is necessary when evaluating lumbar motor control.

The Effects of Aging on Sarcoplasmic Reticulum-Related Factors in the Skeletal Muscle of Mice.

The pathogenesis of sarcopenia includes the dysfunction of calcium homeostasis associated with the sarcoplasmic reticulum; however, the localization in sarcoplasmic reticulum-related factors and differences by myofiber type remain unclear. Here, we investigated the effects of aging on sarcoplasmic reticulum-related factors in the soleus (slow-twitch) and gastrocnemius (fast-twitch) muscles of 3- and 24-month-old male C57BL/6J mice. There were no notable differences in the skeletal muscle weight of these 3- and 24-month-old mice. The expression of Atp2a1, Atp2a2, Sln, and Pln increased with age in the gastrocnemius muscles, but not in the soleus muscles. Subsequently, immunohistochemical analysis revealed ectopic sarcoplasmic reticulum calcium ion ATPase (SERCA) 1 and SERCA2a immunoreactivity only in the gastrocnemius muscles of old mice. Histochemical and transmission electron microscope analysis identified tubular aggregate (TA), an aggregation of the sarcoplasmic reticulum, in the gastrocnemius muscles of old mice. Dihydropyridine receptor α1, ryanodine receptor 1, junctophilin (JPH) 1, and JPH2, which contribute to sarcoplasmic reticulum function, were also localized in or around the TA. Furthermore, JPH1 and JPH2 co-localized with matrix metalloproteinase (MMP) 2 around the TA. These results suggest that sarcoplasmic reticulum-related factors are localized in or around TAs that occur in fast-twitch muscle with aging, but some of them might be degraded by MMP2.

Effects of Aging on Collagen in the Skeletal Muscle of Mice.

Aging affects several tissues in the body, including skeletal muscle. Multiple types of collagens are localized in the skeletal muscle and contribute to the maintenance of normal muscle structure and function. Since the effects of aging on muscle fibers vary by muscle fiber type, it is expected that the effects of aging on intramuscular collagen might be influenced by muscle fiber type. In this study, we examined the effect of aging on collagen levels in the soleus (slow-twitch muscle) and gastrocnemius (fast-twitch muscle) muscles of 3-, 10-, 24-, and 28-month-old male C57BL/6J mice using molecular and morphological analysis. It was found that aging increased collagen I, III, and VI gene expression and immunoreactivity in both slow- and fast-twitch muscles and collagen IV expression in slow-twitch muscles. However, collagen IV gene expression and immunoreactivity in fast-twitch muscle were unaffected by aging. In contrast, the expression of the collagen synthesis marker heat shock protein 47 in both slow- and fast-twitch muscles decreased with aging, while the expression of collagen degradation markers increased with aging. Overall, these results suggest that collagen gene expression and immunoreactivity are influenced by muscle fiber type and collagen type and that the balance between collagen synthesis and degradation tends to tilt toward degradation with aging.

Effects of Obesity in Old Age on the Basement Membrane of Skeletal Muscle in Mice.

Obesity and aging are known to affect the skeletal muscles. Obesity in old age may result in a poor basement membrane (BM) construction response, which serves to protect the skeletal muscle, thus making the skeletal muscle more vulnerable. In this study, older and young male C57BL/6J mice were divided into two groups, each fed a high-fat or regular diet for eight weeks. A high-fat diet decreased the relative gastrocnemius muscle weight in both age groups, and obesity and aging individually result in a decline in muscle function. Immunoreactivity of collagen IV, the main component of BM, BM width, and BM-synthetic factor expression in young mice on a high-fat diet were higher than that in young mice on a regular diet, whereas such changes were minimal in obese older mice. Furthermore, the number of central nuclei fibers in obese older mice was higher than in old mice fed a regular diet and young mice fed a high-fat diet. These results suggest that obesity at a young age promotes skeletal muscle BM formation in response to weight gain. In contrast, this response is less pronounced in old age, suggesting that obesity in old age may lead to muscle fragility.

Effects of stretching on the basement membrane structure in the soleus muscle of Wistar rats.

The basement membrane (BM), mainly composed of collagen IV, plays an important role in the maintenance, protection, and recovery of muscle fibers. Collagen IV expression is maintained by the balance between synthetic and degradative factors, which changes depending on the level of muscle activity. For example, exercise increases collagen IV synthesis, whereas inactivity decreases collagen IV synthesis. However, the effects of stretching on the BM structure remain unclear. Therefore, to investigate the effects of stretching on the BM of the skeletal muscle, we continuously applied stretching to the rat soleus muscle and examined the altered expression of BM-related factors and structure using quantitative polymerase chain reaction (qPCR), western blotting, zymography, immunohistochemistry, and electron microscopy. The results show that stretching increased the matrix metalloproteinase 14 (MMP14) expression and MMP2 activity, and decreased the collagen IV expression and width of the lamina densa in the soleus muscle. These results suggest that stretching promotes BM degradation in the rat soleus muscle. The findings of this study indicate a new influence of stretching on skeletal muscles, and may contribute to the new use of stretching in rehabilitation and sports fields.

Outcomes of Aspiration Prevention Surgery: A Retrospective Cohort Study Using a Japanese Claims Database.

Aspiration prevention surgeries, such as laryngotracheal separation and total laryngectomy are performed to prevent aspiration pneumonia. We aimed to investigate the outcomes of surgery for intractable aspiration and relevant factors. This retrospective cohort study used a nationwide insurance claims database that included company employees and their family members aged < 75 years in Japan. We extracted the data of patients who underwent aspiration prevention surgeries between January 2005 and March 2019. We identified 127 patients (males, 55.9%), of whom 59.8% were aged < 18 years at the surgery. The most common comorbidity was neurological disease (99.2%). The frequency of pneumonia episodes decreased by 1.5 per year after surgery compared with before surgery (p < 0.001). Among patients who received parenteral and enteral nutrition before surgery (n = 92), the adjusted hazard ratio (aHR) for oral intake without parenteral and enteral nutrition was lower in the longer preoperative duration (≥ 14.7 months) for the parenteral and enteral nutrition. However, the difference was not statistically significant (aHR 0.55; 95% confidence interval: 0.15-2.08, p = 0.38). The aHR for oral intake was higher in the ≥ 30 years group than in the < 30 years group (aHR 13.76; 95% confidence intervals: 4.18-42.24; p < 0.001). This study demonstrated that postoperative oral intake was achieved more frequently in patients aged ≤ 30 years than in those aged > 30 years, and supported the effectiveness of aspiration prevention surgery for reducing aspiration pneumonia. Further research is necessary to investigate factors related to postoperative oral intake.

Advantage of a higher position of the tracheostoma with glottic closure for preventing complications related to tracheostomy tube: a retrospective cohort study.

BACKGROUND: Surgery to prevent aspiration has complications related to tracheostomy tube, such as the trachea-brachiocephalic artery fistula. Glottic closure procedure makes tracheostoma at a position higher than the first ring of the trachea and theoretically has a potential to prevent such complications owing to a longer distance between the tip of tracheostomy tube and the tracheal membrane adjacent to the brachiocephalic artery. Our aim is to evaluate the safety of glottic closure in neurologically impaired patients by comparing outcomes with laryngotracheal separation. METHODS: This study is a single-center retrospective study from 2004 to 2019, using data of 15 and 12 patients who underwent glottic closure (GC) and laryngotracheal separation (LTS). The primary outcome was the incidence of postoperative complications induced by tracheostomy tube placement and adjustment of the tracheostomy tube position to prevent these complications, such as by converting to a length-adjustable tube and/or placing gauze between the skin and tube flange. Additionally, we analyzed the anatomical relationship between the tracheostomy tube tip and brachiocephalic artery and measured the distance between them using postoperative CT images. RESULTS: No patients in either group had trachea-brachiocephalic artery fistula. Erosion or granuloma formation occurred in 1 patient (7%) and 4 patients (33%) in the GC and LTS groups, respectively. Adjustment of the tracheostomy tube was needed in 2 patients (13%) and 6 patients (50%) in the GC and LTS groups. CT revealed a higher proportion of patients with the tracheostomy tube tip superior to the brachiocephalic artery in GC than LTS group. The mean tracheostoma-brachiocephalic artery distance was 40.8 and 32.4 mm in the GC and LTS groups. CONCLUSIONS: Glottic closure reduces the risk of postoperative complications related to a tracheostomy tube. This may be due to the higher position of the tracheostoma at the level of the cricoid cartilage, increasing the distance between the tracheostoma and brachiocephalic artery.

The relationship between scapular position and glenohumeral rotational range of motion in high school baseball players.

BACKGROUND: Past research indicated that scapular malposition is related to the glenohumeral internal rotation deficit (GIRD). However, there is no research examining the effect of throwing-related pain on this relationship. This study investigated the relationship between scapular position and range of motion (ROM) and compared the difference in this relationship between with and without throwing-related pain. METHODS: Forty male baseball players in high school were recruited for this study. The existence and degree of throwing-related pain were obtained from a questionnaire. Participants were divided into 2 groups according to the presence or absence of the pain. Glenohumeral internal and external rotation ROM (abduction internal rotation angle and abduction external rotation angle [ABER], respectively) were measured using a digital inclinometer. The pectoralis minor muscle length was measured using a vernier caliper and scapula index, which indicated the scapular position, measured using a measuring tape. All these measurements were taken on both dominant and nondominant sides. The GIRD and total motion arc (TMA) deficit were calculated from the ROM measurements. Groups were compared using a mixed-model analysis of variance. RESULTS: There was a significant interaction between group and ABER dominance. Other variables were not seen as the interaction effect. There was a significant positive correlation between the scapula index and TMA (r = 0.47, P = .02) and a negative correlation between the scapula index and GIRD (r = -0.65, P < .01) in the dominant side of the pain group. In addition, in the nondominant side of the pain group, the scapula index and ABER were significantly correlated (r = 0.43, P = .04). CONCLUSIONS: The results of this study indicate that the scapular position is associated with the glenohumeral ROM in high school baseball players. In addition, this study demonstrated that the scapular internally rotated position was correlated with the GIRD and TMA deficit in high school baseball players who had throwing-related pain. On the other hand, the scapular externally rotated position was correlated with increased ABER, mainly in the pain-free baseball players or on the nondominant side. These results indicated that the scapular position might affect the glenohumeral rotational ROM in high school baseball players.

Reliability of lower leg muscle thickness measurement along the long axis of the muscle using ultrasound imaging, in a sitting position.

[Purpose] To verify the reliability and validity of lower leg muscle thickness (MT) assessment along the muscle's long axis using ultrasound imaging (USI) in a sitting position. [Participants and Methods] Twenty healthy adult female participants (aged, 20.3 ± 0.9 years) were included in the study. Intra- and inter-examiner reliability of the proximal, middle, and distal MT of the tibialis anterior (TA) and medial head of the gastrocnemius (GM) were verified using USI in a sitting position. Additionally, the relationship between MT measurement using USI and muscle cross-sectional area (MCSA) measurement using magnetic resonance imaging (MRI), as well as the ankle joint's maximum muscle strength, were examined. [Results] The reliability of TA and GM MT measurement using USI was high for all regions. The relationship between MCSA measurement using MRI and MT measurement using USI showed a significant correlation in all the regions for both muscles. The relationship between ankle muscle strength and USI of MT was not significantly correlated in any region for both muscles. [Conclusion] Measurement of MT using USI is reliable and valid for MCSA, but must be combined with assessments of other factors for muscle strength.

Basement membrane recovery process in rat soleus muscle after exercise-induced muscle injury.

Purpose: Collagen IV is a component of the basement membrane (BM) that provides mechanical support for muscle fibers. In addition, transcription factor 4 (TCF4) is highly expressed in muscle connective tissue fibroblasts and regulates muscle regeneration. However, the expression of collagen IV and TCF4 (+) cells in response to exercise-induced muscle injury is not well known. Here, we investigated the expression and localization of collagen IV and TCF4 (+) cells during the recovery process after muscle injury induced by different exercise loads.Materials and Methods: Muscle injury was observed in the soleus muscle of young Wistar rats after 12 or 18 sets-downhill running (DR) on a treadmill. After running, the rats were permitted to recover for a period of 0.5 days, 2 days, or 7 days.Results: Ectopic localization of collagen IV in injured muscle fibers was observed after DR, and the number increased at 0.5 days after 18 sets DR and at 2 days after 12 or 18 sets DR as compared to the number observed at baseline. BM disruption was observed after DR. TCF4 (+) cells appeared in the inside and around injured muscle fibers at 0.5 day of recovery. After 18 sets DR, TCF4 (+) cells were more abundant for a longer period than that observed after 12 sets DR.Conclusions: DR induces BM disruption accompanied by muscle fiber damage. It is possible that BM destruction may be accompanied by muscle damage and that TCF4 (+) cells contribute to muscle fiber and BM recovery.

Exposure to tobacco smoke prenatally and during infancy and risk of hearing impairment among children in Japan: A retrospective cohort study.

BACKGROUND: Previous studies of the association between tobacco smoke and hearing loss in children are limited, involve small samples and are cross-sectional. We investigated the association of maternal smoking during pregnancy and exposure to tobacco smoke at age 4 months with hearing impairment at age 3 years in children. METHODS: This population-based retrospective cohort study included 50 734 children born between 2004 and 2010 in Kobe City, Japan. Smoking during pregnancy and exposure to tobacco smoke at 4 months was measured using parent-reported questionnaires. Hearing impairment was determined by the whispered voice test. RESULTS: Of the included children, 3.8% were exposed to smoking only during pregnancy; 3.9% were exposed only to second-hand smoke at 4 months; and 0.9% were exposed to tobacco smoke during pregnancy and at 4 months. The prevalence of hearing impairment at age 3 years was 4.6%. Compared with children not exposed to tobacco smoke prenatally and at 4 months, the risk of hearing impairment was elevated in children exposed to only maternal past smoking during pregnancy (RR 1.26, 95% CI 1.13, 1.40), only second-hand smoke at 4 months (RR 1.30, 95% CI 1.07, 1.56), only smoking during pregnancy (RR 1.68, 95% CI 1.42, 2.00) and smoking during pregnancy and second-hand smoke at 4 months (RR 2.35, 95% CI 1.79, 3.10). CONCLUSIONS: Exposure to tobacco smoke prenatally and postnatally was associated with hearing impairment in children. A prevention of smoking before and during pregnancy and exposure to second-hand smoke postnatally may reduce hearing impairment risk in children.

Prognostic impact of p16 and p53 expression in oropharyngeal squamous cell carcinomas.

BACKGROUNDS: A p16 protein is known to be overexpressed in human papillomavirus-positive head and neck squamous cell carcinoma specimens. p53 is a tumor suppressor protein detectable by immunohistochemistry in carcinogen-associated head and neck squamous cell carcinoma as a result of gene mutations. The purpose of this study is to investigate the prognostic impact of p16 and p53 expression in oropharyngeal squamous cell carcinomas. METHODS: We retrospectively examined the relationship between prognosis, and p16 and p53 expression levels of oropharyngeal squamous cell carcinoma specimens in 53 patients using immunohistochemistry. RESULTS: Overall, 55% of patients were p16 positive and 45% p16 negative, while 28% were p53 positive and 72% p53 negative. The p16 status showed an inverse relationship with the p53 status. A survival analysis by p16 status, p53 status, Union for International Cancer Control stage and main treatment modality demonstrated that only p16 status was related to better prognosis in terms of overall survival and disease-specific survival (3-year overall survival, 87 vs. 62%, P = 0.02; 3-year disease-specific survival, 90 vs. 62%, P = 0.02). To evaluate the practical prognostic factors in oropharyngeal squamous cell carcinoma patients, we classified patients as either p16-positive or p53-negative oropharyngeal squamous cell carcinomas, representing human papillomavirus-related oropharyngeal squamous cell carcinoma with wild-type p53 or the remaining patients with p16-negative or p53-positive OPSCCs, respectively. The former group showed survival advantages in terms of overall survival and disease-specific survival by log-tank test compared with the latter group (3-year overall survival, 96 vs. 58%, P = 0.005; 3-year disease-specific survival, 96 vs. 63%, P = 0.02). CONCLUSIONS: A group of patients who were p16 positive/p53 negative had better prognoses in terms of overall survival and disease-specific survival than that who were p16-positive alone.

[A case of intraorbital solitary fibrous tumor resected successfully with preoperative arterial embolization].

The solitary fibrous tumor (SFT) is a rare spindle cell neoplasm derived from mesenchymal cells. It sometimes recurs clinically, and is categorized as an 'intermediate malignancy' tumor under the WHO (World Health Organization) classification of soft tissue tumors. Several studies have reported on intraorbital SFTs, but none of them has pointed out the utility of preoperative arterial embolization in the case of an intraorbital SFT. A 75-year-old man, who had received a dacryocystectomy for a benign tumor in the right lacrimal sac 30 years previously, visited our hospital complaining of lower eyelid swelling and lachrymation that had persisted for a year. CT and MRI revealed an intraorbital lesion, and the open biopsy specimen showed dense growth of spindle cells, which turned out to be an SFT by immunohistochemistry based on the findings. After preoperative embolization of the infraorbital artery, we removed the tumor with a skin incision on the lower rim of the orbit with little bleeding. The surgical specimen revealed that the tumor was close to a lacrimal canaliculus, which suggested the tumor originated from the lacrimal apparatus considering the patient's past history. He was followed up for three months without recurrences.

Characteristics of injuries related to Kin-Ball sport in Japan: A questionnaire study.

INTRODUCTION: The number of Kin-Ball sport participants is expected to increase in the future. However, there is no report on the characteristics of the injuries associated with Kin-Ball sport. OBJECTIVE: The purpose of this study was to describe the characteristics of injuries relate to Kin-Ball sport. DESIGN: Observational study. SETTING: A self-administered questionnaire was used for data collection. PARTICIPANTS: One hundred ninety Kin-Ball sport participants were included in this study. MAIN OUTCOME MEASURES: The questionnaire was designed based on physical characteristics, participation in Kin-Ball sport, and Kin-Ball sport injuries. Participation in Kin-Ball sport includes the length of time spent playing Kin-Ball sport as well as the playing categories (junior, friendly, champion challenge, champion, over 40). Kin-Ball sport injuries include the presence or absence of injury experience, the site, type, situation, and current injuries or pain associated with Kin-Ball sport. RESULTS: One hundred fifty-two players (80%) of Kin-Ball sport participants were injured. The ankle was the most frequently visited body site (60; 22.1%), and the elbow was the second most visited body site (40; 14.8%). Sprains were the most common type of injury. CONCLUSION: This is the first study to describe the characteristics of injuries relate to Kin-Ball sport. The findings of this study could be beneficial for athletes, coaches, trainers, and clinicians to prevent, or treatment of the injuries.

Examining Movement Patterns, Skeletal Muscle Mass, and Hip Mobility in Office Workers With or Without Lower Back Pain: An Analytical Cross-Sectional Study.

OBJECTIVES: The purpose of this study was to clarify the relationship between Functional Movement Screen (FMS), skeletal muscle mass, and hip mobility in office workers with or without chronic lower back pain (LBP), as well as to determine whether the above items differed between office workers with or without chronic LBP. METHODS: This study utilized an analytic cross-sectional design. The participants were 35 office workers (14 in the LBP group and 21 in the non-lower back pain group, or NLBP) who were willing to cooperate with the request for cooperation in this study. Movement patterns were assessed by FMS and skeletal muscle mass was measured by bioelectrical impedance analysis. Hip mobility was measured by prone hip extension (PHE) and straight leg raising. The correlations between each item and differences in the presence or absence of LBP were analyzed. RESULTS: The LBP and NLBP groups showed different correlations (p<0.05) between total and subcategory scores and skeletal muscle mass. Total FMS score (p=0.02, r=-0.40) and PHE angle (p=0.01, r=0.43) were significantly higher in the LBP group than in the NLBP group. CONCLUSIONS: The FMS shows different relationships between total and subcategory scores and skeletal muscle mass for office workers with or without LBP. In addition, office workers with LBP may have different movement patterns and greater hip extension range of motion than those without LBP.

Effects of 6 weeks of whole-body vibration training on ankle motor control: a randomized controlled trial.

BACKGROUND: Interventions on ankle motor control are important to prevent recurrent ankle sprains. Training using whole-body vibration may easily and effectively improve ankle motor control, but the effects have not been investigated. Therefore, this study aimed to clarify the effects of 6 weeks of training with whole-body vibration on ankle motor control in a dynamic movement task among healthy participants. METHODS: Twenty healthy university students (6 males and 14 females) were randomly allocated to whole-body vibration training and control groups, with 10 participants in each group. The training was performed twice a week for 6 weeks in both groups. Primary outcome was mean ankle angular jerk cost in the star excursion balance test. Secondary outcomes were maximum ankle motion angle and maximum reach distance in the star excursion balance test, ankle proprioception, and range of ankle dorsiflexion motion in the loaded position. RESULTS: There was a significant group × period (pre- and postintervention) interaction for mean ankle angular jerk cost in the direction of ankle abduction/adduction during posterolateral reaching, which was significantly lower at postintervention than that at preintervention in the whole-body vibration group In the whole-body vibration group, the maximum ankle dorsiflexion motion angle during anterior and posterolateral reaching was significantly higher at postintervention than that at preintervention. CONCLUSIONS: Training with whole-body vibration improves ankle motor control in dynamic movement tasks, although the direction of reach and plane of motion are limited. Additionally, training with whole-body vibration is also effective in increasing the ankle dorsiflexion angle during dynamic movement tasks.

Early evaluation of neoadjuvant chemotherapy response using FDG-PET/CT predicts survival prognosis in patients with head and neck squamous cell carcinoma.

BACKGROUND: The purpose of this study was to investigate the possibility of early survival prediction after completion of one cycle of neoadjuvant chemotherapy (NAC) by positron emission tomography (PET)/computed tomography (CT) with (18)F-fluorodeoxyglucose (FDG). METHODS: Fifty-seven patients with advanced head and neck squamous cell carcinoma (HNSCC) underwent FDG-PET/CT scans twice, before and after one cycle of NAC. We calculated the maximal standardized uptake value (SUV(max)) for a primary tumor and/or metastatic lymph nodes and defined %decrease as the %difference in SUV(max) between the two scans divided by that of the initial scan. Patients were classified as responders by PET (%decrease ≥55.5% or post-NAC SUV(max) ≤3.5) and by RECIST (≥30% decrease in size). The local control (LC) rate and the disease-specific survival (DSS) rate were assessed between the responders and non-responders. Multivariate analysis was also performed using the Cox proportional hazards model. RESULTS: In univariate analysis, the PET finding of a primary site was a significant risk factor for LC and DSS rates at 2 years after completion of NAC (P = 0.03 and 0.02, respectively), but there was no difference between responders and non-responders by the RECIST criteria. In a multivariate regression analysis, the PET finding in the primary site and the definitive therapy choice were independent prognostic factors in LC, while the PET finding in the primary site was the only independent prognostic factor in DSS. CONCLUSION: Our preliminary data indicate that the PET finding in the primary lesion after one cycle of NAC was an independent prognostic factor in LC and DSS in patients with HNSCC.

Microbial contamination associated with consumption and the growth in plastic bottled beverage.

Plastic bottles enable the storage of unfinished beverages, and most of microbial contamination has occurred in the unfinished beverage that was left. Therefore, we investigated microorganisms in various beverages contaminated by pouring and drinking directly by mouth from the bottle, and analyzed the growth of microorganisms in the beverages at room temperature. In the pouring test, microbial growth was detected in 60 of 320 samples, and 13 bacterial strains, 49 mold strains, and 8 yeast strains were isolated. Molds including Cladosporium spp., Tramets spp., Bjerkandera spp., and Penicillium spp. accounted for the majority of isolated microorganisms. In the drinking test, microbial growth was detected in 181 of 352 samples, and 225 bacterial strains, 27 mold strains and 77 yeast strains were isolated. Bacteria including Streptococcus spp. such as S. salivarius and Staphylococcus spp. such as S. aureus accounted for the majority of isolated microorganisms. Enterotoxin-producing S. aureus and Bacillus cereus were also isolated. The pH of the beverage influenced the growth of bacteria. The Brix values of the beverage did not correlate with the growth of microorganisms. These results revealed that various microorganisms including foodborne pathogens were able to grow in numerous types of beverages and that the storage of unfinished beverage in inappropriate condition, such as the storage at room temperature led microorganism to grow easily in beverage. Therefore, it is necessary to consume beverages as soon as possible after opening the bottle.

Relationship between ankle-joint angle during dynamic balance task and ankle-joint proprioception in chronic ankle-instability individuals.

BACKGROUND: Chronic ankle instability (CAI) is a major condition in athletes. It is known that both ankle joint proprioception and joint motion control are important for the improvement of CAI, but the relationship between the two has not been clarified. The purpose of this study was to compare ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in healthy and CAI individuals and to verify the relationship between ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in individuals with CAI. METHODS: The participants were 27 females (age 20.3±0.9 years, healthy group: 15, CAI group: 12). The star excursion balance test (SEBT) was used for the dynamic balance task, and the ankle joint angles were measured with a small accelerometer during the movement. The error of the active joint repositioning test (AJRT) was measured to test the proprioception. RESULTS: There was no significant difference in the error in AJRT between the groups, but the joint angle in SEBT was significantly lower in the CAI group than in the healthy group for ankle dorsiflexion only. The error in AJRT of ankle inversion was correlated with the ankle inversion/eversion angle of the SEBT, and the error in AJRT of ankle plantar flexion was correlated with the ankle-dorsiflexion angle of the SEBT. CONCLUSIONS: CAI individuals showed no difference in ankle-joint proprioception compared to healthy individuals, but their ankle-joint-dorsiflexion angle in the dynamic balance task was smaller. Ankle-joint proprioception in CAI individuals was related to the ankle-joint angle in the dynamic balance task.

Action Sequence Learning Is Impaired in Genetically Modified Mice with the Suppressed GABAergic Transmission from the Thalamic Reticular Nucleus to the Thalamus.

The thalamic reticular nucleus (TRN) is a thin sheet of GABAergic neurons surrounding the thalamus, and it regulates the activity of thalamic relay neurons. The TRN has been reported to be involved in sensory gating, attentional regulation, and some other functions. However, little is known about the contribution of the TRN to sequence learning. In the present study, we examined whether the TRN is involved in reward-based learning of action sequence with no eliciting stimuli (operant conditioning), by analyzing the performance of male and female Avp-Vgat-/- mice (Vgatflox/flox mice crossed to an Avp-Cre driver line) on tasks conducted in an operant box having three levers. Our histological and electrophysiological data demonstrated that in adult Avp-Vgat-/- mice, vesicular GABA transporter (VGAT) was absent in most TRN neurons and the GABAergic transmission from the TRN to the thalamus was largely suppressed. The performance on a task in which mice needed to press an active lever for food reward showed that simple operant learning of lever pressing and learning of win-stay and lose-shift strategies are not affected in Avp-Vgat-/- mice. In contrast, the performance on a task in which mice needed to press three levers in a correct order for food reward showed that learning of the order of lever pressing (action sequence learning) was impaired in Avp-Vgat-/- mice. These results suggest that the TRN plays an important role in action sequence learning.