Validity and Reproducibility of an Incremental Sit-To-Stand Exercise Test for Evaluating Anaerobic Threshold in Young,Healthy Individuals

Sit-to-stand exercise (STS) is a common activity of daily living. The objectives of the present study were: 1) to assess the validity of aerobic fitness measurements based on anaerobic thresholds (ATs), during incremental sit-to-stand exercise (ISTS) with and without arm support compared with an incremental cycle-ergometer (CE) test; and 2) to examine the reproducibility of the AT measured during the ISTSs. Twenty-six healthy individuals randomly performed the ISTS and CE test. Oxygen uptakes at the AT (AT-VO₂) and heart rate at the AT (AT-HR) were determined during the ISTSs and CE test, and repeated-measures analyses of variance and Tukey’s post-hoc test were used to evaluate the differences between these variables. Pearson correlation coefficients were used to assess the strength of the relationship between AT-VO₂ and AT-HR during the ISTSs and CE test. Data analysis yielded the following correlations: AT-VO₂ during the ISTS with arm support and the CE test, r = 0.77 (p < 0.05); AT-VO₂ during the ISTS without arm support and the CE test, r = 0.70 (p < 0.05); AT-HR during the ISTS with arm support and the CE test, r = 0.80 (p < 0.05); and AT-HR during the ISTS without arm support and the CE test, r = 0.66 (p < 0.05). The AT-VO₂ values during the ISTS with arm support (18.5 ± 1.9 mL·min^-1·kg^-1) and the CE test (18.4 ± 1.8 mL·min^-1·kg^-1) were significantly higher than those during the ISTS without arm support (16.6 ± 1.8 mL·min^-1·kg^-1; p < 0.05). The AT-HR values during the ISTS with arm support (126 ± 10 bpm) and the CE test (126 ± 13 bpm) were significantly higher than those during the ISTS without arm support (119 ± 9 bpm; p < 0.05). The ISTS with arm support may provide a cardiopulmonary function load equivalent to the CE test; therefore, it is a potentially valid test for evaluating AT-VO2 and AT-HR in healthy, young adults.

Key points

• The ISTS is a simple test that varies only according to the frequency of standing up, and requires only a small space and a chair.
• The ISTS with arm support is valid and reproducible, and is a safe test for evaluating AT in healthy young adults.
• For evaluating the AT, the ISTS may serve as a valid alternative to conventional CPX, using either a cycle ergometer or treadmill, in cases where the latter methods are difficult to implement.

Key words: Sit-to-stand, cycle ergometer, anaerobic threshold, correlations, reproducibility, validity     

Effects of Sustained‐Release Beraprost in Patients With Primary Glomerular Disease or Nephrosclerosis: CASSIOPEIR Study Results

TRK‐100STP, a sustained‐release preparation of the orally active prostacyclin analogue beraprost sodium, targets renal hypoxia. This study aimed to show the superiority of TRK‐100STP over placebos in patients with chronic kidney disease (with either primary glomerular disease or nephrosclerosis) to determine the recommended dose. CASSIOPEIR (Chronic Renal Failure Asian Study with Oral PGI₂ Derivative for Evaluating Improvement of Renal Function) was a randomized, double‐blind, placebo‐controlled study conducted at 160 sites in seven Asia‐Pacific countries and regions. Eligible patients (n = 892) were randomized to TRK‐100STP 120, 240 μg, or placebo for a treatment period of up to 4 years. The primary efficacy endpoint was time to first occurrence of a renal composite: doubling of serum creatinine or occurrence of end‐stage renal disease. No significant differences were observed in composite endpoints between TRK‐100STP and placebo (P = 0.5674). Hazard ratios (95% CI) in the TRK‐100STP 120 and 240 μg vs. placebo groups were 0.98 (0.78, 1.22) and 0.91 (0.72, 1.14), respectively. The overall incidence of adverse events and adverse drug reactions was comparable between treatment arms.     

Impacts of Recombinant Human Erythropoietin Treatment During Predialysis Periods on the Progression of Chronic Kidney Disease in a Large‐Scale Cohort Study (Co‐JET study)

The effect of recombinant human erythropoietin (rHuEPO) treatment on the progression of chronic kidney disease (CKD) has not been fully evaluated in Japan. We therefore retrospectively evaluated this in a sub‐cohort of a prospective multicenter study to investigate optimal hemoglobin (Hb) level of CKD patients on hemodialysis (HD) treated with rHuEPO; Japan Erythropoietin Treatment Study for Target Hb and Survival (JET study). Effect of rHuEPO treatment during predialysis period to delay initiation of HD was retrospectively assessed in 2434 patients from the JET study comparing groups with and without rHuEPO treatment. The assessment was done by Cox proportional hazards regression analysis and inverse probability‐weighted (IPW) analysis to adjust for time‐dependent confounders. The weights used in the IPW analysis were calculated using a logistic model that included baseline confounders and time‐dependent variables. During the predialysis period, 71.7% (1746 patients) were treated with rHuEPO (mean Hb level of 8.7 g/dL at initiation of rHuEPO treatment). Covariates significantly associated with initiation of rHuEPO treatment were Hb level, serum creatinine level, age, diabetes, cardiac insufficiency, and hypertension. The adjusted hazard ratio for time until HD initiation under rHuEPO treatment was 0.272 (95% CI, 0.223–0.331; P < 0.001) in the Cox analysis and 0.63 (95% CI, 0.53–0.76; P < 0.0001) in the IPW analysis. This retrospective study suggests that rHuEPO treatment during the predialysis period has preventive effects on the progression of CKD although further prospective investigation on the efficacy is needed.     

Evaluation of the pharmacokinetics of linezolid in an obese Japanese patient

We evaluated the pharmacokinetics of linezolid in the case of an obese Japanese patient (body weight 116 kg; body mass index 37 kg/m(2)). Linezolid was administered at a dose of 600 mg by intravenous drip infusion for 60-90 min at 12-h intervals. The results showed increased clearance of linezolid and a reduced serum concentration compared to population pharmacokinetic parameters, with trough levels below the 90% minimum inhibitory concentration. However, linezolid was effective for improving lung infection and inflammation in our patient, which may be due to its particularly effective transfer into lung tissues. Linezolid undergoes slow non-enzymatic oxidation in vivo that may be increased in obese patients, and this may account for the greater clearance. Our findings are useful for the planning of linezolid therapy in obese patients.     

Influence of Food Restriction Combined with Voluntary Running on Bone Morphology and Strength in Male Rats

Athletes, in particular endurance athletes and dancers, are chronically exposed to a state of low energy availability due to insufficient dietary energy intake and massive exercise energy expenditure. Low energy availability sometimes causes bone fragility, thereby increasing the risk of bone disorders. Although the decrease in energy availability shows no sexual dimorphism, epidemiological studies have reported that bone disorders are less frequent in male athletes than in female athletes. We hypothesized that bone tissue was not affected by low energy availability in males. The purpose of this study was to examine the influence of food restriction combined with voluntary running training on bone morphology and strength in adult male rats. Fourteen-week-old male Sprague–Dawley rats were divided randomly into four groups: control (C) group, food restriction (R) group, exercise (Ex) group, and food restriction plus exercise (REx) group. For the R and REx groups, 30 % food restriction was carried out in comparison with the C group. Bone strength, bone mineral density (BMD), bone architecture, and bone turnover rate were measured after a 13-week experimental period. Bone strength was not significantly lower in the REx group compared with the C group. BMD and trabecular bone volume showed no difference among groups. These findings indicate that bone morphology and strength were little affected by food restriction combined with exercise training in adult male rats.     

Respiratory involvement in IgG4-related Mikulicz’s disease

'Immunoglobulin G4 (IgG4)-related disease' is a new clinical concept of multi-organ diseases, with Mikulicz's disease (MD) being a clinical phenotype of IgG4-related disease. To clarify the clinical characteristics of respiratory involvement associated with IgG4-related MD, we retrospectively assessed 25 patients with MD, 11 (44%) of whom had allergic symptoms, and 7 (28%) of whom complained of respiratory problems. Thirteen patients (52%) presented with pulmonary and/or mediastinal lesions (P-MD) on chest computed tomography (CT), and 11 (44%) had lesions limited to the lacrimal and/or salivary glands (L-MD). Mean serum total protein, IgG, and IgG4 concentrations were significantly higher and CH50 was significantly lower in the P-MD than in the L-MD group. Immune complex was present only in the P-MD group. Chest CT images showed bronchial wall thickening, consolidation, nodule(s), interlobular thickening, ground glass opacity, pleural thickening/effusion, and mediastinal lymphadenopathy. Five of seven patients who underwent histological examination of the lungs had abundant IgG4-positive plasma cell infiltrates (IgG4/IgG-positive plasma cells >40%), but the other two did not. These findings suggest that respiratory lesions are not rare in patients with IgG4-related MD, and that they present with various manifestations. IgG4-related MD should be differentiated from similar diseases, such as sarcoidosis, bronchial asthma, Sj?gren's syndrome, and malignant lymphoma.     

Silver oxide‐containing hydroxyapatite coating has in vivo antibacterial activity in the rat tibia

Bacterial infection is a serious postoperative complication of joint replacement. To prevent infections related to implantation, we have developed a novel antibacterial coating with Ag‐containing hydroxyapatite (Ag‐HA). In the present study, we examined the antibacterial activity of Ag‐HA implant coatings in the medullary cavity of rat tibiae. Forty 10‐week‐old rats received implantation of Ag‐HA‐ or HA‐coated titanium rods, then were inoculated with ～1.0 × 10² colony‐forming units of methicillin‐resistant Staphylococcus aureus. Bacterial counts were calculated for rats euthanized at 24, 48, and 72 h postoperatively. Serum levels of Ag (in the Ag‐HA group only) were calculated for rats euthanized at 24, 48, 72 h and 4 weeks. Radiographic evaluations of bone infection were also performed at 4 weeks. Tibiae from both groups showing infection were evaluated histologically. Significant differences in bacterial counts were seen at 24, 48, and 72 h. Mean concentrations of Ag in serum peaked about 48 h after implantation, then gradually decreased. Mean radiographic scores for infection were significantly lower with Ag‐HA implants than with HA implants. Histological examination showed better results for abscesses, bone resorption, and destruction of cortical bone around Ag‐HA‐coated implants. These results indicate that Ag‐HA coatings may help prevent surgical‐site infections associated with joint replacement. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1195–1200, 2013