A novel needle electrode for intraoperative fourth cranial nerve neurophysiological mapping.

OBJECTIVES: Trochlear nerve (CN-IV) mapping method has not been confirmed to date. The compound muscle action potential (CMAP) of CN-IV cannot be recorded because of the low mapping sensitivity and anatomical characteristics of the superior oblique muscle (SOM). The aim of this study was to evaluate the effectiveness of a novel needle electrode (NNE), for the intraoperative mapping of CN-IV. MATERIALS AND METHODS: The NNEs were inserted in the target extraocular muscles in 19 patients. We compared the CMAP amplitude of the NNE with that of the conventional needle electrode (CNE). Furthermore, we investigated the dissimilarity between the CMAP of the CN-IV and other extraocular cranial nerves (ECNs) and the correlation between the readings of the CN-IV mapping and its postoperative functional outcome. RESULTS: The CMAP of CN-IV has been measured in nine patients (47.4%). The CMAP of CN-IV was distinguishable from other ECNs. The CMAP of the NNE was found to be three times higher than that of the CNE. Although the NNE has shown the potential to record the CN-IV's CMAP, 4 cases ended up having a CN-IV postoperative dysfunction. CONCLUSIONS: For the first time, we confirmed the possibility of intraoperative mapping the CN-IV using an NNE inserted into the SOM. The NNE can also be useful for other neurophysiological monitoring methods.

Improved home BP profile with dapagliflozin is associated with amelioration of albuminuria in Japanese patients with diabetic nephropathy: the Yokohama add-on inhibitory efficacy of dapagliflozin on albuminuria in Japanese patients with type 2 diabetes study (Y-AIDA study).

BACKGROUND: The Y-AIDA study was designed to investigate the renal- and home blood pressure (BP)-modulating effects of add-on dapagliflozin treatment in Japanese individuals with type 2 diabetes mellitus (T2DM) and albuminuria. METHODS: We conducted a prospective, multicenter, single-arm study. Eighty-six patients with T2DM, HbA1c 7.0-10.0%, estimated glomerular filtration rate (eGFR) ≥ 45 mL/min/1.73 m2, and urine albumin-to-creatinine ratio (UACR) ≥ 30 mg/g creatinine (gCr) were enrolled, and 85 of these patients were administered add-on dapagliflozin for 24 weeks. The primary and key secondary endpoints were change from baseline in the natural logarithm of UACR over 24 weeks and change in home BP profile at week 24. RESULTS: Baseline median UACR was 181.5 mg/gCr (interquartile range 47.85, 638.0). Baseline morning, evening, and nocturnal home systolic/diastolic BP was 137.6/82.7 mmHg, 136.1/79.3 mmHg, and 125.4/74.1 mmHg, respectively. After 24 weeks, the logarithm of UACR decreased by 0.37 ± 0.73 (P < 0.001). In addition, changes in morning, evening, and nocturnal home BP from baseline were as follows: morning systolic/diastolic BP - 8.32 ± 11.42/- 4.18 ± 5.91 mmHg (both P < 0.001), evening systolic/diastolic BP - 9.57 ± 12.08/- 4.48 ± 6.45 mmHg (both P < 0.001), and nocturnal systolic/diastolic BP - 2.38 ± 7.82/- 1.17 ± 5.39 mmHg (P = 0.0079 for systolic BP, P = 0.0415 for diastolic BP). Furthermore, the reduction in UACR after 24 weeks significantly correlated with an improvement in home BP profile, but not with changes in other variables, including office BP. Multivariate linear regression analysis also revealed that the change in morning home systolic BP was a significant contributor to the change in log-UACR. CONCLUSIONS: In Japanese patients with T2DM and diabetic nephropathy, dapagliflozin significantly improved albuminuria levels and the home BP profile. Improved morning home systolic BP was associated with albuminuria reduction. Trial registration The study is registered at the UMIN Clinical Trials Registry (UMIN000018930; http://www.umin.ac.jp/ctr/index-j.htm ). The study was conducted from July 1, 2015 to August 1, 2018.

Clinical factors associated with the symptoms of constipation in patients with diabetes mellitus: A multicenter study.

BACKGROUND AND AIM: Changes in treatment protocols for patients with diabetes mellitus (DM) may influence the functions of the digestive tract. This study examined possible clinical factors associated with the symptoms of constipation in patients with DM. METHODS: This was a multicenter study. Participants were consecutive Japanese patients undergoing treatment for type 1 or type 2 DM. Constipation was evaluated using the gastrointestinal symptom rating scale. Diabetic neuropathy was evaluated by the presence or absence of peripheral neuropathy of the lower limbs. RESULTS: Of 419 participants, 258 were men and 161 women (ratio: 1.6:1), with a mean age of 63.6 ± 12.5 years. In multivariate analysis, symptoms of constipation were significantly associated with age (odds ratio [OR] = 1.02, 95% confidence interval [CI]: 1.01-1.04, P = 0.032), lower mental component summary (OR = 3.31, 95% CI: 1.69-6.48, P < 0.001), diabetic retinopathy (OR = 1.99, 95% CI: 1.14-3.45, P = 0.015), and diabetic neuropathy (OR = 1.86, 95% CI: 1.10-3.16, P = 0.021). In patients with peripheral neuropathy of the lower limbs, regardless of the presence of other complications (diabetic nephropathy and diabetic retinopathy), the prevalence of symptoms of constipation was twice that of patients without peripheral neuropathy (40.0-49.1% vs 22.0%). Diabetic drugs were not associated with symptoms of constipation. CONCLUSIONS: Diabetic neuropathy, defined as peripheral neuropathy of the lower limbs, was significantly associated with symptoms of constipation. Peripheral neuropathy of the lower limbs is not a direct risk factor for constipation but may be a useful criterion when assessing whether constipation is associated with DM.

Highly efficient hole injection from Au electrode to fullerene-doped triphenylamine derivative layer.

Triphenylamine derivatives are superior hole-transport materials. For their application to high-functional organic semiconductor devices, efficient hole injection at the electrode/triphenylamine derivative interface is required. Herein, we report the design and evaluation of a Au/fullerene-doped α-phenyl-4'-[(4-methoxyphenyl)phenylamino]stilbene (TPA) buffer layer/TPA/Au layered device. It exhibits rectification conductivity, indicating that hole injection occurs more easily at the Au/fullerene-doped TPA interface than at the Au/TPA interface. The Richardson-Schottky analysis of the device reveals that the hole injection barrier (ΦB) at the Au/fullerene-doped TPA interface decreases to 0.021 eV upon using C70 as a dopant, and ΦB of Au/TPA is as large as 0.37 eV. The reduced ΦB of 0.021 eV satisfies the condition for ohmic contact at room temperature (ΦB [Formula: see text] 0.025 eV). Notably, C70 doping has a higher barrier-reduction effect than C60 doping. Furthermore, a noteworthy hole-injection mechanism, in which the ion-dipole interaction between TPA and fullerenes plays an important role in reducing the barrier height, is considered based on cyclic voltammetry. These results should facilitate the design of an electrode/organic semiconductor interface for realizing low-voltage driven organic devices.

Intracardiac conduction time as a predictor of cardiac resynchronization therapy response: Results of the BIO|SELECT pilot study.

BACKGROUND: Quadripolar left ventricular (LV) leads are capable of sensing and pacing the left ventricle from 4 different electrodes, which may potentially improve patient response to cardiac resynchronization therapy (CRT). OBJECTIVE: We measured 3 different time intervals: right ventricular (RV)-sensed to LV-sensed during intrinsic rhythm (RVs-LVs), RV-paced to LV-sensed (RVp-LVs), and LV-paced to LV-sensed (LVp-LVs, between distal [LV1] and proximal pole on a quadripolar LV lead), and assessed their association with CRT response in terms of LV end-systolic volume (LVESV) and a composite benefit index (CBI) comprising LVESV, LV ejection fraction (LVEF), brain natriuretic peptide level, and NYHA class. METHODS: A CRT-defibrillator system with quadripolar LV lead was implanted in 196 patients (mean age 69 years, mean LVEF 30%, left bundle-branch block [LBBB] 58%). Conduction intervals were measured before hospital discharge. At baseline and 7-month follow-up, echocardiographic and other components of CBI were determined. RESULTS: The mean RVs-LV1s, RVp-LV1s, and LVp-LVs delays were 68 ± 38 ms, 132 ± 34 ms, and 99 ± 31 ms, respectively. From baseline to 7 months, LVESV decreased by 17.3% ± 28.6%. The RVs-LV1s interval correlated stronger with CBI (R2 = 0.12, P < .00001) than with LVESV change (R2 = 0.05, P = .006). In contrast, RVp-LV1s did not correlate and LVp-LVs correlated only weakly with CRT response. The subgroup of patients (44%) with LBBB and RVs-LV1s above the lower quartile (≥34 ms) showed the greatest response to CRT. CONCLUSION: The RVs-LVs interval during intrinsic rhythm is relevant for CRT success, whereas RVp-LVs and LVp-LVs intervals did not predict CRT response.

Quantitative analysis of operators' flow line in the cell culture for controlled manual operation.

INTRODUCTION: Although cell culture has been widely used in the life sciences, there are still many aspects of this technique that are unclear. In this study, we have focused on the manual operations in the cell culture process and try to analyze the operators' flow line. METHODS: During a course of approximately 6 years, we obtained the operators' flow line data from two places (three layouts) and 38 operators (93 subcultures) using two network cameras and a motion detection software (Vitracom SiteView). RESULTS: Our investigation succeeded in quantifying the flow line of the subculture process and analyzed the time taken to carry out the process, to travel around the workplace. For the subculture process, the total time of the process being rerated the time of the operation in the place where the main operation is performed; the total distance of travel and the counts of travel not being related to the total time of the process. Based on these results, we propose a new way of evaluating the efficiency of cell culture process in terms of time and traveling. We believe that the results of this study can guide cell culture operators in handling cells more efficiently in cell manufacturing processes. CONCLUSIONS: The flow line analysis method suggested by us can record the operators involved and improve the efficiency and consistency of the process; it can, therefore, be introduced in cell manufacturing processes. In addition, this method only requires network cameras and motion detection software, which are inexpensive and can be set up easily.

Time-course colony tracking analysis for evaluating induced pluripotent stem cell culture processes.

Increasing the yield and maintaining a high quality of induced pluripotent stem cells (iPSCs) is necessary for manufacturing iPSCs at the industrial scale. However, because iPSCs are delicate, it is important to evaluate their quality during processing. To examine the status of cultured iPSCs non-invasively, morphology-based iPSC colony evaluation may be an efficient technology for cellular status monitoring and analysis. In this study, we examined the effectiveness of time-course colony tracking analysis for evaluating the iPSC culture process. Particularly, we obtained detailed time-course data to evaluate the effect of the pipetting technique on cell dissociation before seeding. Although the pipetting process causes severe shear stress to cells, which affects their quality, these effects have not been quantitatively analyzed because of their complex and uncontrollable parameters. By analyzing the heterogeneity and time-course responses of individual colonies, our colony tracking analysis revealed a critically damaged population caused by pipetting stress which could not be detected in conventional bulk analysis. Moreover, by comprehensively analyzing colony tracking data, which links the time-course morphology and marker staining results with each colony, we found that colony morphology is only highly correlated with the undifferentiated marker in the final stage, with a lower correlation in the early stages. Thus, colony tracking analysis provides a way to quantify cellular morphological information when evaluating complex iPSC manufacturing processes.

Bone metabolic activity around dental implants under loading observed using bone scintigraphy.

PURPOSE: The purpose of this study was to determine dynamic changes in bone metabolism around osseointegrated titanium implants under mechanical stress. MATERIALS AND METHODS: Two titanium implants were inserted parallel to each other in the tibiae of rats and perpendicular to the bone surface with the superior aspect of the implant exposed. Eight weeks after insertion, closed coil springs with 0.5, 1.0, 2.0, and 4.0 N were applied to the exposed superior portion of the implant for 7 weeks to apply a continuous mechanical stress. Bone scintigrams were performed using a gamma camera with a modified high-resolution pinhole collimator. Images were made at 1, 4, 7, 10, 14, 21, 28, 49, and 56 days after insertion and at 3 days and at weekly intervals until 7 weeks after load application. The ratio of the metabolic activity around the implants to that around a reference site (uptake ratio) was established. The Friedman, Steel, and Tukey tests (P < .05) were used to assess statistical significance. RESULTS: In the process of osseointegration, the uptake ratio increased during the first week after implant insertion and then gradually decreased. During the initial 3 weeks the uptake ratio was significantly higher than at 1 day after insertion. In the process of load application, the uptake ratio increased with 2.0- and 4.0-N loads; it was significantly higher until 6 weeks than it had been before load application. CONCLUSIONS: Bone metabolism around the implants increases with loading and depends on the magnitude and period of the loading.

Visualization of morphological categories of colonies for monitoring of effect on induced pluripotent stem cell culture status.

From the recent advances, there are growing expectations toward the mass production of induced pluripotent stem cells (iPSCs) for varieties of applications. For such type of industrial cell manufacturing, the technology which can stabilize the production efficiency is strongly required. Since the present iPSC culture is covered by delicate manual operations, there are still quality differences in produced cells from same culture protocols. To monitor the culture process of iPSCs with the quantified data to evaluate the culture status, we here introduce image-based visualization method of morphological diversity of iPSC colonies. We have set three types of experiments to evaluate the influential factors in iPSC culture technique that may disturb the undifferentiation status of iPSC colonies: (Exp. 1) technical differences in passage skills, (Exp. 2) technical differences in feeder cell preparation, and (Exp. 3) technical differences in maintenance skills (medium exchange frequency with the combination of manual removal of morphologically irregular colonies). By measuring the all existing colonies from real-time microscopic images, the heterogenous change of colony morphologies in the culture vessel was visualized. By such visualization with morphologically categorized Manhattan chart, the difference between technical skills could be compared for evaluating appropriate cell processing.

Comparisons of cell culture medium using distribution of morphological features in microdevice.

As the number of available cell types grows, it becomes necessary to develop more effective ways to optimize the cell-culture medium for each cell line and culture condition. However, because of the vast number of parameters that must be decided, such as the combination of components, optimization is both laborious and costly. Microdevices are a cost-effective way to perform such evaluations because they use only a small volume of media and enable high-throughput analyses. However, assays performed in microdevices are themselves minimized, and each assay unit (well/chamber) commonly contains an insufficient number of cells for comprehensive evaluations such as gene-expression or flow-cytometry analyses. To address this issue, we introduced image-based analysis in conjunction with microdevice assays; this approach allows quantification of every cell in each assay unit. To quantitatively profile differences in cellular behaviors in a microdevice under different culture media conditions, we developed a non-staining image-based analysis method that utilizes cellular morphology. Our approach combines the structural advantages of microdevices, which can increase the stability of images, and the quantitative advantages of an image-based cell evaluation technique that utilizes time-course population change in several morphological features. Our results demonstrate that cellular changes due to small alterations in the concentration of serum in medium or differences in the basal medium can be profiled using only microscopic images.

Non-invasive quality evaluation of confluent cells by image-based orientation heterogeneity analysis.

In recent years, cell and tissue therapy in regenerative medicine have advanced rapidly towards commercialization. However, conventional invasive cell quality assessment is incompatible with direct evaluation of the cells produced for such therapies, especially in the case of regenerative medicine products. Our group has demonstrated the potential of quantitative assessment of cell quality, using information obtained from cell images, for non-invasive real-time evaluation of regenerative medicine products. However, image of cells in the confluent state are often difficult to evaluate, because accurate recognition of cells is technically difficult and the morphological features of confluent cells are non-characteristic. To overcome these challenges, we developed a new image-processing algorithm, heterogeneity of orientation (H-Orient) processing, to describe the heterogeneous density of cells in the confluent state. In this algorithm, we introduced a Hessian calculation that converts pixel intensity data to orientation data and a statistical profiling calculation that evaluates the heterogeneity of orientations within an image, generating novel parameters that yield a quantitative profile of an image. Using such parameters, we tested the algorithm's performance in discriminating different qualities of cellular images with three types of clinically important cell quality check (QC) models: remaining lifespan check (QC1), manipulation error check (QC2), and differentiation potential check (QC3). Our results show that our orientation analysis algorithm could predict with high accuracy the outcomes of all types of cellular quality checks (>84% average accuracy with cross-validation).

Influences of increased training volume on exercise performance, physiological and psychological parameters.

BACKGROUND: The aim of this study was to investigate the influence of excessive training on exercise performance and physiological and psychological parameters. METHODS: Eight physically active males (age, mean±standard deviation [SD]: 23±3 years) completed 3 weeks of an intervention program consisting of normal (N), intensified (IT), and recovery (R) training phases (7 days for each phase). Physiological and psychological parameters were measured at rest before the intervention (Pre), and every Monday, Wednesday, and Saturday (day 1, day 3, day 6, respectively), and exercise performance tests were performed before the intervention (Pre) and every Saturday (day 6) during the intervention period. RESULTS: The estimated energy expenditure during a training session revealed a more than two-fold increase from the N phase to the IT phase. During the IT phase, augmented training volume significantly affected the POMS (fatigue) and motivation towards training (P<0.05) scores, and these values returned to baseline levels during the R phase. Moreover, resting serum testosterone concentrations significantly decreased and exercise-induced cortisol responses were diminished during the IT phase (P<0.05). The altered endocrine responses were still observed during the subsequent R phase. Resting serum BAP levels (an index of antioxidant potential) significantly increased during the N phase (P<0.05). Meanwhile, there was no significant change in exercise performance, resting d-ROM (an index of oxidative stress) values, or salivary amylase activity. CONCLUSIONS: Increases in training stress altered psychological parameters, resting testosterone concentrations, and exercise-induced cortisol responses. Exercise performance did not correlate with training stress, suggesting that monitoring endocrine and psychological parameters is essential during intensified training periods.

Morphological Evaluation of Nonlabeled Cells to Detect Stimulation of Nerve Growth Factor Expression by Lyconadin B.

The success of drug development is greatly influenced by the efficiency of drug screening methods. Recently, phenotype-based screens have raised expectations, based on their proven record of identifying first-in-class drugs at a higher rate. Although fluorescence images are the data most commonly used in phenotype-based cell-based assays, nonstained cellular images have the potential to provide new descriptive information about cellular responses. In this study, we applied morphology-based evaluation of nonlabeled microscopic images to a phenotype-based assay. As a study case, we attempted to increase the efficiency of a cell-based assay for chemical compounds that induce production of nerve growth factor (NGF), using lyconadin B as a model compound. Because the total synthesis of lyconadin B was accomplished very recently, there is no well-established cell-based assay scheme for further drug screening. The conventional cell-based assay for evaluating NGF induction requires two types of cells and a total of 5 days of cell culture. The complexity and length of this assay increase both the risk of screening errors and the cost of screening. Our findings show that analysis of cellular morphology enables evaluation of NGF induction by lyconadin B within only 9 h.

Parametric analysis of colony morphology of non-labelled live human pluripotent stem cells for cell quality control.

Given the difficulties inherent in maintaining human pluripotent stem cells (hPSCs) in a healthy state, hPSCs should be routinely characterized using several established standard criteria during expansion for research or therapeutic purposes. hPSC colony morphology is typically considered an important criterion, but it is not evaluated quantitatively. Thus, we designed an unbiased method to evaluate hPSC colony morphology. This method involves a combination of automated non-labelled live-cell imaging and the implementation of morphological colony analysis algorithms with multiple parameters. To validate the utility of the quantitative evaluation method, a parent cell line exhibiting typical embryonic stem cell (ESC)-like morphology and an aberrant hPSC subclone demonstrating unusual colony morphology were used as models. According to statistical colony classification based on morphological parameters, colonies containing readily discernible areas of differentiation constituted a major classification cluster and were distinguishable from typical ESC-like colonies; similar results were obtained via classification based on global gene expression profiles. Thus, the morphological features of hPSC colonies are closely associated with cellular characteristics. Our quantitative evaluation method provides a biological definition of 'hPSC colony morphology', permits the non-invasive monitoring of hPSC conditions and is particularly useful for detecting variations in hPSC heterogeneity.

The influence of environmental temperature on appetite-related hormonal responses.

BACKGROUND: Acute exercise in the heat has been shown to reduce appetite. However, the influence of exercise in the cold on appetite regulation remains unclear. The aim of this study was to compare exercise-induced appetite regulation under three different environmental temperatures. METHODS: Eleven male participants completed three experimental trials on the following separate days: exercise in the heat (36 °C), exercise at neutral temperature (24 °C), and exercise in the cold (12 °C). The exercise trials consisted of pedaling exercises for 30 min at 65% of maximal oxygen uptake (VO2max). Blood samples were collected repeatedly to determine plasma ghrelin, peptide YY (PYY) and other hormonal concentrations. Subjective feelings of hunger and tympanic temperature were also monitored. RESULTS: Tympanic temperature was significantly higher in the 36 °C trial than that of the other two trials (P < 0.05). The subjective feelings of hunger in the 36 °C and 24 °C trials were significantly lower than those in the 12 °C trial (P < 0.05). Plasma ghrelin concentration decreased significantly with exercise in all conditions (P < 0.05), and the responses were not significantly different among the three conditions. Plasma PYY concentration increased significantly after the exercise in the 24 °C trial only (P < 0.05), with no significant difference among the three trials. CONCLUSIONS: These results suggest that exposure to hot or cold temperatures during exercise did not affect exercise-induced plasma ghrelin and PYY responses. However, the exercise-induced reduction of subjective hunger was significantly attenuated in a cold environment.

A 3-day high-fat/low-carbohydrate diet does not alter exercise-induced growth hormone response in healthy males.

OBJECTIVE: The purpose of the present study was to examine the effects of 3 days isoenergetic high-fat/low-carbohydrate diet (HF-LC) relative to low-fat/high-carbohydrate diet (LF-HC) on the exercise-induced growth hormone (GH) response in healthy male subjects. DESIGN: Ten healthy young males participated in this study. Each subject consumed the HF-LC (18±1% protein, 61±2% fat, 21±1% carbohydrate, 2720 kcal per day) for 3 consecutive days after consuming the LF-HC (18±1% protein, 20±1% fat, 62±1% carbohydrate, 2755 kcal per day) for 3 consecutive days. After each dietary intervention period, the hormonal and metabolic responses to an acute exercise (30 min of continuous pedaling at 60% of V˙O2max) were compared. The intramyocellular lipid (IMCL) contents in the vastus lateralis, soleus, and tibialis anterior were evaluated by proton magnetic resonance spectroscopy. RESULTS: Serum GH concentrations increased significantly during the exercise after both the HF-LC and LF-HC periods (P<0.05). However, the exercise-induced GH response was not significantly different between the two periods. Fat utilization and lipolytic responses during the exercise were enhanced significantly after the HF-LC period compared with the LF-HC period. IMCL content did not differ significantly in any portion of muscle after the dietary interventions. CONCLUSIONS: We could not show that short-term HF-LC consumption changed significantly exercise-induced GH response or IMCL content in healthy young males.

Image-based focused counting of dividing cells for non-invasive monitoring of regenerative medicine products.

Despite the growing numbers of successful applications in regenerative medicine, biotechnologies for evaluating the quality of cells remain limited. To evaluate the cultured cells non-invasively, image-based cellular assessment method holds great promise. However, although there are various image-processing algorithms, very few studies have focused to prove the effectiveness of phase contrast images with risk assessment example that reflects actual difficulties in regenerative medicine products. In this study, we developed a simple image-processing method to recognize the number of dividing cells in time-course phase-contrast microscopic images, and applied this method to assess the irregular proliferation behavior in normal cells. Practically, as a model, rapid proliferating human fibrosarcoma cells were mixed in normal human fibroblasts in the same culture dish, and their sarcoma existence was evaluated. As a result, the existence of sarcoma population in normal cell sample could be feasibly detected within earliest period of cell culture by their irregular rise of accumulated counts of dividing cells. Our image-processing technique also illustrates the technical effectiveness of combining intra-frame and inter-frame image processing to accurately count only the dividing cells. Our concept of focused counting of dividing cells shows a successful example of image-based analysis to quickly and non-invasively monitor the regular state of regenerative medicine products.

Effects of different periods of hypoxic training on glucose metabolism and insulin sensitivity.

This study examined the effects of different periods of hypoxic training on glucose metabolism. Sedentary subjects underwent hypoxic training (FiO2 = 15.0%) for either 2 weeks (2-week group; n = 11) or 4 weeks (4-week group; n = 10). The 2-week group conducted training sessions on 6 days week(-1) for 2 weeks, whereas the 4-week group conducted training sessions on 3 days week(-1) for 4 weeks. Body fat mass or abdominal fat area did not change after training period in either group. VO2max increased in both groups after training period (42 ± 2 versus 43 ± 2 ml min(-1) kg(-1) in 2-week group, 41 ± 1 versus 42 ± 2 ml min(-1) kg(-1) in 4-week group). Both groups showed a reduction in mean blood pressure after training period (92 ± 3 versus 90 ± 3 mmHg in 2-week group, 91 ± 2 versus 87 ± 2 mmHg in 4-week group, P ≤ 0.05). No change was observed in blood glucose response after glucose ingestion after training period. However, area under the curve for serum insulin concentrations after glucose ingestion significantly decreased in only 4-week group (6910 ± 763 versus 5812 ± 872 µIU ml(-1) 120 min, P ≤ 0.05). In conclusion, hypoxic training reduced blood pressure with independent on training duration. However, a longer period of hypoxic training led to greater improvements in insulin sensitivity compared with equivalent training over a shorter period, suggesting that hypoxic training programmes for more than 4 weeks might be more beneficial for improving insulin sensitivity.

Impact of exercise and moderate hypoxia on glycemic regulation and substrate oxidation pattern.

OBJECTIVE: We examined metabolic and endocrine responses during rest and exercise in moderate hypoxia over a 7.5 h time courses during daytime. METHODS: Eight sedentary, overweight men (28.6 ± 0.8 kg/m2) completed four experimental trials: a rest trial in normoxia (FiO2 = 20.9%, NOR-Rest), an exercise trial in normoxia (NOR-Ex), a rest trial in hypoxia (FiO2 = 15.0%, HYP-Rest), and an exercise trial in hypoxia (HYP-Ex). Experimental trials were performed from 8:00 to 15:30 in an environmental chamber. Blood and respiratory gas samples were collected over 7.5 h. In the exercise trials, subjects performed 30 min of pedaling exercise at 60% of VO2max at 8:00, 10:30, and 13:00, and rested during the remaining period in each environment. Standard meals were provided at 8:30, 11:00, and 13:30. RESULTS: The areas under the curves for blood glucose and serum insulin concentrations over 7.5 h did not differ among the four trials. At baseline, %carbohydrate contribution was significantly higher in the hypoxic trials than in the normoxic trials (P<0.05). Although exercise promoted carbohydrate oxidation in the NOR-Ex and HYP-Ex trials, %carbohydrate contribution during each exercise and post-exercise period were significantly higher in the HYP-Ex trial than in the NOR-Ex trial (P<0.05). CONCLUSION: Three sessions of 30 min exercise (60% of VO2max) in moderate hypoxia over 7.5 h did not attenuate postprandial glucose and insulin responses in young, overweight men. However, carbohydrate oxidation was significantly enhanced when the exercise was conducted in moderate hypoxia.

4 weeks of high-intensity interval training does not alter the exercise-induced growth hormone response in sedentary men.

This study determined the effects of high-intensity interval training on the exercise-induced growth hormone (GH) responses, whole body and regional fat content. Twenty-four sedentary males were randomized to either a high-intensity interval training (HIT) group or a low-intensity continuous training (LT) group. The HIT group performed intermittent exercises at 85% of [Formula: see text], whereas the LT group performed continuous exercise for 22 min at 45% of [Formula: see text]. Before and after 4 weeks of training, hormonal and metabolic responses to acute exercise were determined. Acute exercise significantly increased GH concentrations in both groups (p < 0.05). However, the responses did not change after training period in either group. Furthermore, the training did not significantly affect intramyocellular or intrahepatic lipid content in either group. The present study indicates that 4 weeks of high-intensity interval training does not alter the exercise-induced GH responses, whole body fat mass or intramyocellular and intrahepatic lipid content in sedentary males.