ABSTRACT
Sakamoto, A, Naito, H, and Chow, CM. Hyperventilation-aided recovery for extra repetitions on bench press and leg press. J Strength Cond Res 34(5): 1274-1284, 2020-Hyperventilation (HV)-induced alkalosis, an ergogenic strategy, improved repeated pedaling sprint performance through enhanced H removal. However, it did not confer beneficial effects on other forms of exercises. This study investigated the benefits of HV-aided recovery on lifting repetitions and joint velocity during resistance training involving multiple joints and both concentric and eccentric contractions. Eleven power-trained men (mean ± SD age: 22.5 ± 4.3 years, training experience: 8.3 ± 3.6 years) performed 6 sets each of bench press and leg press at 80% 1 repetition maximum. Each set was continued until failure, with a 5-minute recovery between sets. In protocol A, HV was implemented for 30 seconds before the first, third, and fifth sets of each exercise (HV-aided recovery), whereas spontaneous breathing continued throughout the recovery before the second, fourth, and sixth sets (control recovery). In protocol B, the order of the HV and control recoveries was reversed. For both protocols, reductions in repetitions (range: -4.7% to -22.5%) and velocity (range: -23.1% to -37.7%) were consistently observed after control recovery (p < 0.05), whereas HV-aided recovery resulted in increased repetitions (range: +21.3% to +55.7%) and velocity (range: +6.3% to +15.3%) (p < 0.05) or no reductions in these measures from the previous set. The total repetitions performed across 6 sets (protocols A and B combined) were greater after the HV-aided than control recovery (p ≤ 0.001) in bench press (44 ± 10 vs. 36 ± 10 reps, increased by 27.1 ± 24.1%) and leg press (64 ± 9 vs. 50 ± 15 reps, increased by 35.2 ± 29.5%). Hyperventilation-aided recovery may boost the effectiveness of resistance training through increased training volume and lifting velocity.
Subject(s)
Athletic Performance , Hyperventilation , Resistance Training/methods , Weight Lifting , Humans , Male , Young AdultABSTRACT
BACKGROUND: Pneumonia is the third leading cause of death in Japan. All elderly people aged 65 years or older are recommended to receive a pneumococcal vaccine. A subsidy for part of the cost of routine pneumococcal vaccination in this age group was introduced in 2014. Factors related to vaccination behavior among elderly adults have not been well reported. The purpose of this study was to investigate factors associated with vaccine uptake among elderly people in Japan. METHODS: We conducted a cross-sectional study, using a self-administered questionnaire among elderly club members aged 65 years or older in one city of Japan in April 2017. The participants were selected from among all elderly club members in the study area. Variables extracted from the questionnaire were analyzed using logistic regression analysis. RESULTS: A total of 208 elderly club members participated in the study. The mean age (± SD) was 77.2 (± 5.3) years. The pneumococcal vaccination rate was 53.2%. Logistic regression analysis revealed three variables that had a significant association with pneumococcal vaccination: a recommendation for vaccination from medical personnel (aOR 8.42, 95% CI 3.59-19.72, p < 0.001), receiving influenza vaccination in any of the previous three seasons (aOR 3.94, 95% CI 1.70-9.13, p = 0.001), and perception of the severity of pneumonia (aOR 1.23, 95% CI 1.03-1.48, p = 0.026). CONCLUSIONS: Although the pneumococcal vaccination rate in this study was increased compared with previous reports, almost half of study participants had not yet received vaccination. Our findings could be helpful for developing vaccination strategies to increase the vaccine coverage in the elderly population.
Subject(s)
Pneumococcal Vaccines/administration & dosage , Vaccination/psychology , Vaccination/statistics & numerical data , Aged , Aged, 80 and over , Attitude to Health , Cross-Sectional Studies , Female , Humans , Influenza Vaccines/administration & dosage , Japan , Male , Physician-Patient Relations , Pneumonia/prevention & control , Pneumonia/psychology , Surveys and QuestionnairesABSTRACT
PURPOSE: Maximum force exertion against various resistance levels (heavy-light) is commonly implemented to improve both strength- and speed-oriented components of power. Medium-light resistances allow rapid accelerations, yet incur significant decelerations in the later concentric phase to bring the bar to a halt, which may limit the concentric effort and, therefore, the effectiveness of training. Accordingly, ballistic actions have been recommended. This study evaluated the effectiveness of power bench press training, with the bar thrown on a Smith machine (BPthrow) or without throwing (BPnon-throw), for developing strength and shot put distance. METHODS: Nine university shot-putters performed BPthrow and BPnon-throw at 50, 40 and 30% 1RM, as well as seated and standing shot put trials. Peak angular velocities at the elbow were measured in these tasks using a wireless electro-goniometer. Participants underwent 24 sessions of training (12 weeks) with either BPthrow (n = 5) or BPnon-throw (n = 4) at the three intensities (20 s × 2 sets at 50, 40 and 30% 1RM). RESULTS: The peak elbow velocity during BPthrow was 1.7 times greater than BPnon-throw for all intensities. The velocity of BPthrow at 30% 1RM (854.7°/s), however, was still slower than seated (1121.3°/s) and standing (1539.1°/s) shot puts. BPthrow training significantly improved 1RM (+ 10.0%) and the distances of seated (+ 11.7%) and standing (+ 3.8%) shot puts, while no performance changes occurred after BPnon-throw training. CONCLUSION: When undergoing power bench press against medium-light resistances, maximum ballistic actions are important strategies for improving 1RM and shot put performance of university shot-putters.
Subject(s)
Athletic Performance/physiology , Muscle Strength/physiology , Acceleration , Adult , Athletes , Exercise Test/methods , Exercise Therapy/methods , Humans , Male , Muscle, Skeletal/physiology , Resistance Training/methods , Universities , Weight Lifting/physiology , Young AdultABSTRACT
Sakamoto, A, Naito, H, and Chow, C-M. Effects of hyperventilation on repeated pedaling sprint performance: short vs. long intervention duration. J Strength Cond Res 32(1): 170-180, 2018-Previously, hyperventilation (HV)-induced respiratory alkalosis, implemented during the last 30 seconds of each 60-second recovery that separated repeated pedaling sprints, has been shown to attenuate performance decrement. The present study investigated whether the ergogenic effects of HV would hold if the HV duration was shortened or extended. Seventeen power-trained athletes performed 10 seconds × 10 sets of standing pedaling sprints on a cycle ergometer, with a 60-second interset recovery and the load (kp) set at 0.075 × body mass, under 3 breathing conditions: control, HV of 15 seconds (HVshort), and HV of 45 seconds (HVlong). Subjects breathed spontaneously during each 60-second recovery for the control condition. Under HVshort and HVlong conditions, subjects hyperventilated at 60 breaths·min with near-maximum tidal volume during the last 15 or 45 seconds, respectively, of each recovery period. Peak and mean pedaling power outputs (POpeak and POmean) were documented for each sprint set to compare performance decrements between conditions. No significant condition effect or condition × time interaction was found for POpeak and POmean. The lack of ergogenic effects with HVlong may be ascribed to a complex interaction between the positive (augmented buffering effects) and negative effects of HV (decreased aerobic energy metabolism and exaggerated discomfort sensation of increased ventilatory work). For HVshort, the implemented duration may have been too short to yield positive physiological effects. A practical implication is that ergogenic effects may be impaired when HV is too short or too long, with the duration of around 30 seconds being the target for this exercise type.
Subject(s)
Athletes , Athletic Performance/physiology , Bicycling/physiology , Hyperventilation/physiopathology , Body Mass Index , Ergometry , Female , Humans , Male , Oxygen Consumption , Time Factors , Young AdultABSTRACT
BACKGROUND: Repeated ghrelin administration leads to improvements in symptoms, muscle wasting and exercise tolerance in cachectic patients with pulmonary disease. We investigated the optimal ghrelin dose for underweight patients with chronic respiratory failure. METHODS: In this multicenter, randomized, dose-comparison exploratory study, 44 cachectic patients with chronic respiratory failure were randomly assigned pulmonary rehabilitation with intravenous twice-daily administration of 1 or 2 µg/kg ghrelin for 3 weeks. The primary endpoint was improvement in 6-min walking distance (6 MWD). The secondary endpoint was change in peak VO2. RESULTS: Twenty-one patients were assigned to the 1 µg/kg ghrelin group and 23 to the 2 µg/kg ghrelin group. Change from baseline 6 MWD after treatment was similar between groups(1 µg/kg: 53.9 m, 2 µg/kg: 53.9 m, p = 0.99). Mean change in peak VO2 was significantly greater in the 2 µg/kg group (63.1 ml/min) than in the 1 µg/kg group (-63.8 ml/min, p = 0.048). Food intake and lean body mass significantly increased in both groups, and the St. George Respiratory Questionnaire score, body weight, and body mass index were remarkably improved in only the 2 µg/kg group, although there was no significant difference between groups. No treatment-related serious events were reported for either group. CONCLUSION: Improvements in the oxygen uptake capacity were greater in patients receiving 2 µg/kg ghrelin twice daily for 3 weeks than in those receiving 1 µg/kg, although exercise tolerance was similar between groups at the end of the 3-week treatment period. Thus, a twice daily dose of 2 µg/kg ghrelin is recommended over 1 µg/kg ghrelin for patients with chronic respiratory failure and weight loss.
Subject(s)
Cachexia/complications , Ghrelin/administration & dosage , Respiratory Insufficiency/complications , Respiratory Insufficiency/drug therapy , Aged , Body Composition , Body Weight , Chronic Disease , Eating , Energy Intake , Exercise Test , Exercise Therapy , Exercise Tolerance , Female , Ghrelin/adverse effects , Humans , Male , Middle Aged , Oxygen Consumption , Quality of Life , Respiratory Insufficiency/rehabilitation , Surveys and Questionnaires , WalkingABSTRACT
PURPOSE: Hyperventilation, implemented during recovery of repeated maximal sprints, has been shown to attenuate performance decrement. This study evaluated the effects of hyperventilation, using strength exercises, on muscle torque output and EMG amplitude. METHODS: Fifteen power-trained athletes underwent maximal isokinetic knee extensions consisting of 12 repetitions × 8 sets at 60°/s and 25 repetitions × 8 sets at 300°/s. The inter-set interval was 40 s for both speeds. For the control condition, subjects breathed spontaneously during the interval period. For the hyperventilation condition, subjects hyperventilated for 30 s before each exercise set (50 breaths/min, PETCO2: 20-25 mmHg). EMG was recorded from the vastus medialis and lateralis muscles to calculate the mean amplitude for each contraction. RESULTS: Hyperventilation increased blood pH by 0.065-0.081 and lowered PCO2 by 8.3-10.3 mmHg from the control values (P < 0.001). Peak torque declined with repetition and set numbers for both speeds (P < 0.001), but the declining patterns were similar between conditions. A significant, but small enhancement in peak torque was observed with hyperventilation at 60°/s during the initial repetition phase of the first (P = 0.032) and fourth sets (P = 0.040). EMG amplitude also declined with set number (P < 0.001) for both speeds and muscles, which was, however, not attenuated by hyperventilation. CONCLUSION: Despite a minor ergogenic effect in peak torque at 60°/s, hyperventilation was not effective in attenuating the decrement in torque output at 300°/s and decrement in EMG amplitude at both speeds during repeated sets of maximal isokinetic knee extensions.
Subject(s)
Accidental Falls , Alkalosis, Respiratory/physiopathology , Exercise/physiology , Fatigue/physiopathology , Hyperventilation/physiopathology , Muscle, Skeletal/physiology , Adult , Athletes , Biomechanical Phenomena/physiology , Electromyography/methods , Female , Humans , Kinetics , Male , Young AdultABSTRACT
Repeated high-intensity sprints incur substantial anaerobic metabolic challenges and create an acidic muscle milieu that is unfavorable for subsequent performance. Hyperventilation, resulting in respiratory alkalosis, acts as a compensatory mechanism for metabolic acidosis. This study tested the hypothesis that hyperventilation performed during recovery intervals would attenuate performance decrement in repeated sprint pedaling. Thirteen male university athletes performed 10 sets of 10-second maximal pedaling on a cycle ergometer with a 60-second recovery between sets under control (spontaneous breathing) and hyperventilation conditions in a crossover counter-balanced manner. Pedaling load was set at 0.075 × body mass. Peak and mean power outputs were documented for each set to compare performance decrements for 10 sets between conditions. Hyperventilation (60 breaths per minute and end-tidal partial pressure of CO2 maintained at 20-25 mm Hg) was performed 30 seconds before each sprint set. This intervention successfully increased blood pH by 0.03-0.07 but lowered P(CO2) by 1.2-8.4 mm Hg throughout exercise (p < 0.001). The peak and mean power outputs, and blood [La] accumulation were not significantly different between the conditions. However, a significant condition × time interaction existed for peak power (p = 0.035) and mean power (p = 0.023), demonstrating an attenuation in power decrement in later sprint sets with hyperventilation. In conclusion, hyperventilation implemented during recovery intervals of repeated sprint pedaling attenuated performance decrements in later exercise bouts that was associated with substantial metabolic acidosis. The practical implication is that hyperventilation may have a strategic role for enhancing training effectiveness and may give an edge in performance outcomes.
Subject(s)
Acid-Base Imbalance/prevention & control , Adaptation, Physiological/physiology , Bicycling/physiology , Hyperventilation , Blood Gas Analysis , Ergometry , Exercise Test/methods , Heart Rate , Humans , Lactic Acid/blood , Male , Muscle Fatigue/physiology , Oxygen Consumption/physiology , Physical Endurance/physiology , Sampling Studies , Task Performance and Analysis , Young AdultABSTRACT
During a set of resistance exercise performed until exhaustion, the relationship between intensity and the number of repetitions can be affected by lifting speed, with faster speeds producing higher numbers. The hypothesized mechanisms include enhanced utilization of the stretch-shortening cycle. This study investigated muscle activations under varying speeds and intensities during bench press using surface electromyography (EMG) to suggest further mechanisms for the above finding. Thirteen weight-trained men (21.7 ± 3.6-year-old) performed bench press until fatigue under five intensities (40-80% 1RM), and four speeds (slow 5.6-s/repetition, medium 2.8-s/repetition, fast 1.9-s/repetition, and ballistic maximum speed). Surface EMG was recorded from the pectoralis, deltoid, and triceps for root-mean-square amplitude and median frequency. EMG amplitudes were greater for faster and heavier conditions before fatigue. Faster conditions, however, produced a significant fall in amplitude during the final concentric phase compared to slower movements. After fatigue, EMG amplitude increased, with the speed effect being maintained. The intensity effect on amplitude either disappeared or remained similar, depending on the muscles. Median frequencies before fatigue were similar among speeds and intensities. The fall in frequency after fatigue was similar across speeds, but greater for lighter intensities. It was concluded that reduced muscle activation during the final concentric phase in faster conditions allowed a better muscle pump, explaining the increased repetition numbers. Fatigue levels are likely to have been similar across speeds, but greater for lower intensities. An incomplete rise in EMG amplitude after fatigue for lower intensities could imply an increased contribution of central fatigue or neuromuscular transmission failure.
Subject(s)
Lifting , Muscle, Skeletal/physiology , Acceleration , Adolescent , Adult , Exercise/physiology , Exercise Therapy , Humans , Male , Muscle Contraction/physiology , Muscle Strength/physiology , Physical Exertion/physiology , Resistance Training , Weight Lifting/physiology , Young AdultABSTRACT
This study aimed to determine whether high-intensity dumbbell exercise involving both concentric and eccentric contractions would provide a temporary alleviation of delayed-onset muscle soreness (DOMS). It also examined the effect of alleviated muscle soreness on dynamic muscle performance using a stretch-shortening cycle (SSC; peak angular acceleration and velocity of the elbow during both lowering and concentric phases) to provide indirect evidence that DOMS contributes to the dynamic performance decrement after eccentric injury. Thirteen untrained adults performed 30 maximal isokinetic eccentric contractions of the elbow flexors to induce eccentric damage. Five sets of arm curls using a dumbbell (equivalent to 70% of isometric maximal voluntary contraction) were then performed until failure on days 1, 2, 3, and 5 of recovery. Muscle soreness significantly decreased after each session of dumbbell exercise (p = 0.001). Isometric strength further decreased immediately after dumbbell exercise, indicating muscle fatigue (p < 0.001). Dynamic performance variables were less affected by fatigue, however, with performance being reduced only for peak lowering velocity (p < 0.001). Other measures of dynamic performance were relatively constant after dumbbell exercise, particularly on days 2 and 3 when soreness was greatest. It was concluded that high-intensity concentric/eccentric dumbbell exercise was able to temporarily alleviate DOMS and that this reduction in soreness served to counter the effect of peripheral muscle fatigue during dynamic activities. Practical applications of this study are that after eccentric damage, alleviation of muscle soreness through an optimal warm-up may be helpful to temporarily recover dynamic muscle performance. Free-weight loading is one suggested technique to temporarily manage DOMS.
Subject(s)
Muscle Fatigue/physiology , Muscle Strength/physiology , Muscle, Skeletal/injuries , Pain/physiopathology , Resistance Training , Adult , Female , Humans , Isometric Contraction/physiology , Male , Muscle, Skeletal/physiology , Pain/etiology , Time Factors , Weight-Bearing/physiologyABSTRACT
Case 1 was a 22-year-old younger sister of identical twins who had smoked 10 cigarettes per day for 4 years since she was 18. She was admitted to our hospital due to dyspnea on exertion, dry cough and bilateral diffuse reticulonodular infiltrates on chest computed tomography (CT). Histological findings of transbronchial lung biopsy demonstrated nodular lesions consisting of spindle-shaped mononuclear cells. Immunohistochemical studies revealed that the cytoplasm of these mononuclear cells showed positive reactions to CD1a. Based on these findings, she was given a diagnosis of pulmonary Langerhans cell histiocytosis (LCH). She reduced the number of cigarettes smoked to 1 cigarette per week. After 6 months, her respiratory symptoms and radiographic abnormalities had improved. Case 2 was the elder twin sister of case 1. She had smoked 5 cigarettes per day for 4 years since she was 18. She presented no respiratory symptoms. However, as the diagnosis in case 1 was LCH, a chest CT was taken which revealed 3 small nodular lesions. After six months, there were no significant changes on chest CT. At the time of writing, she is 23-years-old and continues to smoke, however, has no respiratory symptoms.
Subject(s)
Diseases in Twins , Histiocytosis, Langerhans-Cell/pathology , Female , Humans , Twins, Monozygotic , Young AdultABSTRACT
A 70-year-old woman, who underwent treatment with prednisolone and methotrexate for rheumatoid arthritis, was admitted to our hospital due to rapidly progressive dyspnea. A chest CT scan showed diffuse ground-glass opacities and reticulonodular shadows in both lungs. Intubation was performed due to severe hypoxia. The color of the bronchoalveolar lavage, using three sequential aliquots, became progressively more reddish, suggesting alveolar hemorrhage. Based on this, we made a diagnosis of diffuse alveolar hemorrhage. To the best of our knowledge, few studies have reported cases of diffuse alveolar hemorrhage associated with rheumatoid arthritis as an underlying disease. We consider that diffuse alveolar hemorrhage may occur as a complication of rheumatoid arthritis.
Subject(s)
Arthritis, Rheumatoid/complications , Hemorrhage/etiology , Lung Diseases/etiology , Pulmonary Alveoli , Aged , Female , HumansABSTRACT
A 77-year-old woman presented with a 3-month history of right chest pain and a low-grade fever. Right pleural effusion had been detected at another hospital. Her chest CT scan revealed right pleural effusion, right pleural thickening, and bilateral multiple lung nodules. No specific findings were obtained from an examination of the pleural effusion. Thoracoscopic pleural and lung biopsies were conducted. Histologically, the tumor had an infiltrative growth pattern in the fibrously-thickened parietal pleura, visceral pleura, and lung parenchyma. The tumor was composed of epithelioid and spindle cells, and in some sections, the tumor cells had intracytoplasmic vacuoles, and had formed an immature vascular lumen. Proliferation in a papillary fashion in the alveolar spaces and vascular involvement of tumor were also seen. Immunohistochemically, the tumor cells were positive for factor VIII-related antigen, CD31, and CD34, and negative for calretinin and WT-1. The tumor was therefore diagnosed as pulmonary epithelioid hemangioendothelioma (PEH), which is a rare, low-to-moderate grade vascular tumor of the lung. This disease should be included in the differential diagnosis together with malignant pleural mesothelioma, in cases demonstrating unusual pleural thickening.
Subject(s)
Hemangioendothelioma, Epithelioid/pathology , Lung Neoplasms/pathology , Mesothelioma/pathology , Pleural Neoplasms/pathology , Aged , Diagnosis, Differential , Female , HumansABSTRACT
This study examined the recovery of static and dynamic muscle performance after eccentric damage with and without repeated exercise, using different exercise modes between the initial and subsequent exercise bouts. Twelve nonweight-trained adults performed both control and repeated exercise conditions. Soreness, limb circumference, static joint angles, creatine kinase (CK), isometric strength, and dynamic muscle performance involving a stretch-shortening cycle (SSC) were monitored for 7 days to evaluate the recovery. After baseline measures, subjects performed 30 maximal isokinetic eccentric contractions (90 degrees/second) of the elbow flexors in each experiment. For the control condition, no treatment was applied. For the repeated exercise condition, 5 sets of arm curls using dumbbells (70% isometric maximal voluntary contraction of each testing day) were performed until failure on days 1, 2, 3, and 5 of recovery. Significant condition vs. time interactions existed in circumference (p = 0.012), static relaxed angle (p = 0.013), isometric strength (p = 0.039), and dynamic extension angle (p = 0.039), suggesting a slightly delayed onset of recovery with the repeated exercise. SSC performance changed more in parallel with soreness after eccentric exercise than did the other measures. It was concluded that the repeated bout effect was present, although slightly reduced, when subsequent exercise performed before recovery was intense and differed in mode from the initial eccentric exercise. Practical applications of this research are that resistance training may be continued after eccentric damage; however, a minor delay in the onset of recovery may occur depending on training modes. Muscle soreness is a good indicator of performance decrement during dynamic movements following eccentric damage.
Subject(s)
Isotonic Contraction/physiology , Muscle Fatigue/physiology , Muscular Diseases/etiology , Pain/etiology , Recovery of Function/physiology , Resistance Training , Adaptation, Physiological , Adult , Analysis of Variance , Arthrometry, Articular , Creatine Kinase/blood , Cross-Over Studies , Elbow/physiology , Female , Humans , Isometric Contraction/physiology , Male , Muscle Strength/physiology , Muscular Diseases/blood , Muscular Diseases/diagnosis , Muscular Diseases/prevention & control , Myofibrils/physiology , Pain/blood , Pain/diagnosis , Pain/prevention & control , Pain Measurement , Range of Motion, Articular/physiology , Resistance Training/adverse effects , Resistance Training/methodsABSTRACT
A 61-year-old woman was admitted to our hospital for examination of an abnormal shadow on her chest X-ray film taken in October 2006. Chest CT film taken in November 2006 revealed lymphadenopathy in the left side of the neck, as well as in the supraclavicular, axillary, mediastinal, and hilar areas, as well as around the pancreas. Diffuse small nodules were seen along the bronchovascular bundles and interlobular pleura. Bronchoscopic examination revealed lymphocyte accumulation and increased CD4/8 ratio in bronchoalveolar lavage fluid. Based on noncaseating epithelioid cell granulomas seen in transbronchial lung biopsy, we diagnosed having sarcoidosis. In April 2008, she complained of abdominal discomfort and a skin lesion. New lymphadenopathy was palpated on the right side of the neck and the left axillary region. On a chest X-ray film and chest CT film, multiple swollen lymph nodes which became even more swollen than those in November 2006 were observed. She received surgical resection of the neck lymph nodes and a pathological diagnosis of Hodgkin's lymphoma was established. This was a rare case of sarcoidosis-lymphoma syndrome.
Subject(s)
Hodgkin Disease/complications , Sarcoidosis/complications , Female , Hodgkin Disease/pathology , Humans , Middle Aged , Sarcoidosis/pathology , SyndromeABSTRACT
Laboratory microbial fuel cells were supplied with artificial wastewater and used to examine how supplementation with poly iron sulfate, an inorganic polymer flocculant widely used in wastewater-treatment plants, affects electricity generation and anode microbiomes. It is shown that poly iron sulfate substantially increases electric outputs from microbial fuel cells. Microbiological analyses show that iron and sulfate separately affect anode microbiomes, and the increase in power output is associated with the increases in bacteria affiliated with the families Geobacteraceae and/or Desulfuromonadaceae. We suggest that poly iron sulfate is an effective additive for increasing the electric output from microbial fuel cells. Other utilities of poly iron sulfate in microbial fuel cells are also discussed.
Subject(s)
Bioelectric Energy Sources/microbiology , Iron/chemistry , Sulfates/chemistry , Wastewater/chemistry , Deltaproteobacteria , Electrodes , Flocculation , Waste Disposal, Fluid/methods , Wastewater/microbiologyABSTRACT
Methicillin-resistant Staphylococcus aureus (MRSA) has rapidly emerged as a cause of severe and intractable skin infection. At present, there are no effective topical treatments, and infection or colonization by MRSA of the skin raises serious medical problems. We developed an ultrasonic levitation washer that generates silver ions (Ag(+)) and ozone (O3) to clean and sterilize medical devices. We report the effect of ultrasonic levitation (levitation) with Ag(+) and O3 on MRSA in vitro and in vivo. Antimicrobial effect against six MRSA strains of all agr types was examined under three in vitro conditions; cells floating in a water tank, cells infiltrating-, and cells forming a biofilm on an atelocollagen membrane. In the in vivo studies, we assayed the number of MRSA organisms that survived treatment on murine skin ulcers and evaluated the ulcer size. Levitation with Ag(+) dramatically decreased the survival of MRSA floating in a water tank. Levitation with Ag(+) and O3 significantly decreased the viability of MRSA that had infiltrated or formed a biofilm on atelocollagen membranes regardless of the level of biofilm production. In vivo studies showed that the number of MRSA on murine skin ulcers was significantly decreased when 15-min treatment was performed for 7 consecutive days and that the ulcer size was significantly decreased after the seventh treatment course. Levitation with Ag(+) and O3 may be a valuable tool for treating MRSA infestation of the skin and for accelerating wound healing.
Subject(s)
Disinfection/instrumentation , Methicillin-Resistant Staphylococcus aureus , Ozone , Silver , Animals , Biofilms , Collagen , Electrolysis , Male , Membranes, Artificial , Mice , Mice, Inbred C57BL , Oxidation-Reduction , Skin Ulcer/microbiologySubject(s)
Intubation, Intratracheal/adverse effects , Mediastinal Emphysema/diagnosis , Mediastinal Emphysema/etiology , Subcutaneous Emphysema/diagnosis , Subcutaneous Emphysema/etiology , Aged , Comorbidity , Female , Humans , Mediastinal Emphysema/diagnostic imaging , Pneumonia, Pneumocystis/therapy , Subcutaneous Emphysema/diagnostic imaging , Tomography, X-Ray Computed , Trachea/injuriesABSTRACT
This study investigated the effect of movement velocity on the relationship between loading intensity and the number of repetitions of bench press. Thirteen healthy men (age = 21.7 +/- 1.0 years; weight = 76.8 +/- 2.5 kg; 1 repetition maximum [1RM] = 99.5 +/- 6.0 kg), who were involved in regular weight training, voluntarily participated in the experiment. Subjects performed bench presses on a Smith machine at 5 different intensities (40-80% 1RM), repeated for 4 velocity conditions (slow: 0.15 +/- 0.03 m.s(-1); medium: 0.32 +/- 0.07 m.s(-1); fast: 0.52 +/- 0.12 m.s(-1); ballistic: maximum velocity), which were randomly assigned over 5 experimental sessions after a 1RM test. Velocity significantly changed the relationship between intensity (%1RM) and the number of reps performed (p < 0.001), with faster velocities producing a higher number of reps. A significant interaction between intensity and velocity meant that velocity had a much greater effect on repetitions at lower intensities. These results suggest that the benefits of using a stretch-shortening cycle during faster movements outweigh the associated disadvantages from the force-velocity relationship. The practical applications of this study are that, when trainees are assigned a resistance training with specific RM values, the lifted intensity (%1RM) or weights will not be consistent unless velocity is controlled during training.