Measurement of respiratory function in isolated cardiac mitochondria using Seahorse XFe24 Analyzer: applications for aging research

Mitochondria play a critical role in the cardiomyocyte physiology by generating majority of the ATP required for the contraction/relaxation through oxidative phosphorylation (OXPHOS). Aging is a major risk factor for cardiovascular diseases (CVD) and mitochondrial dysfunction has been proposed as potential cause of aging. Recent technological innovations in Seahorse XFe24 Analyzer enhanced the detection sensitivity of oxygen consumption rate and proton flux to advance our ability study mitochondrial function. Studies of the respiratory function tests in the isolated mitochondria have the advantages to detect specific defects in the mitochondrial protein function and evaluate the direct mitochondrial effects of therapeutic/pharmacological agents. Here, we provide the protocols for studying the respiratory function of isolated murine cardiac mitochondria by measuring oxygen consumption rate using Seahorse XFe24 Analyzer. In addition, we provide details about experimental design, measurement of various respiratory parameters along with interpretation and analysis of data.     

Enamel remineralization effect of a dentifrice containing calcium sodium phosphosilicate: an optical coherence tomography observation

Objective: The purpose of this study was to examine the effects of a dentifrice containing 5% calcium sodium phosphosilicate (CSP) on the remineralization of the enamel using optical coherence tomography (OCT).

Materials and methods: Bovine incisors were sliced and shaped in a rectangular form. One group of five specimens was treated with undersaturated 0.1 M lactic acid buffer solution (pH 4.75) for 10?min and then placed in artificial saliva (pH 7.0) (De group). Other specimens were stored in solutions of toothpaste containing CSP for 10?min, followed by 10-min immersion in the lactic acid buffer solution twice a day before storage in artificial saliva (CSP group). An additional group was stored in only artificial saliva (control group). OCT imaging on the selected location of the enamel surface was performed. The peak intensity and width at 1/e² were recorded in each of the six areas on the sample and averaged, and the sample size of each group was six. The integrated value in units (dB?×?μm) was calculated in the area of peak intensity. The data for each group was subjected to one-way repeated-measures ANOVA and Tukey HSD tests (α?=?0.05).

Results: The changes in integrated values of each group were different. A slight but significant increase in the integrated value was observed in the control group, whereas a slight but significant decrease in the value was observed the De group. Integrated values increased in the CSP group.

Conclusions: Remineralization occurred upon immersion in the toothpaste containing CSP.     

Square-stepping exercise and fall risk factors in older adults: a single-blind, randomized controlled trial

BACKGROUND: Decreased fitness of the lower extremities is a potentially modifiable fall risk factor. This study aimed to compare two exercise programs--square-stepping exercise (SSE), which is a low-cost indoor program, and walking--for improving the fitness of the lower extremities. METHODS: We randomly allocated 68 community-dwelling older adults (age 65-74 years) to either the SSE or walking group (W group). During the 12-week regimen, the SSE group participated in 70-minute exercise sessions conducted twice a week at a local health center, and the W group participated in outdoor supervised walking sessions conducted weekly. The W group was instructed to increase the number of daily steps. Prior to and after the program, we obtained information on 11 physical performance tests for known fall risk factors and 3 self-reported scales. The fall incidence was followed-up for 8 months. RESULTS: At 12 weeks postregimen, significant differences were observed between the two exercise groups with respect to leg power (1 item), balance (2 items), agility (2 items), reaction time (2 items), and a self-reported scale (1 item); the SSE group demonstrated a marked improvement in the above-mentioned items with Group x Time interactions. Significant time effects were observed in the tests involving chair stands, functional reach, and standing up from a lying-down position without Group x Time interactions. During the follow-up period, the fall rates per person-year in the SSE and W groups were 23.4% and 33.3%, respectively (p =.31). CONCLUSION: Although further studies are required, SSE is apparently more effective than walking in reducing fall risk factors, and it appears that it may be recommended as a health promotion exercise in older adults.     

Radial augmentation index is related to cardiovascular risk in hemodialysis patients

Cardiovascular accidents related to atherosclerosis are the leading cause of death among hemodialysis patients, which makes continuous monitoring of their cardiovascular status crucial. Recently, a handy device for monitoring the augmentation index (AIx) in the radial artery was introduced in Japan, enabling the use of the AIx in addition to pulse wave velocity (PWV) in the management of hemodialysis patients. In this study the AIx, PWV, abdominal aortic calcification index (ACI), and left ventricular mass index (LVMI) were serially assessed in 108 hemodialysis patients. The radial AIx was monitored using a newly introduced tonometer (HEM-9010AI), and the interrelationships among the measured parameters and their contributions to the risk of cardiovascular accidents were evaluated. The radial AIx was significantly higher in hemodialysis patients than in healthy subjects (N = 50) and was well correlated with risk markers such as LVMI (r = 0.30, P = 0.019) and ACI (r = 0.38, P < 0.001), but not with PWV. Multiregression analysis showed that radial AIx was also significantly associated with LVMI, ACI and blood pressure; PWV was associated with other parameters such as age, blood pressure, and ACI. The AIx and ACI were both significantly increased in patients with cardiovascular complications. Although PWV was strongly increased in the hemodialysis patients, it failed to discriminate between these subgroups of high-risk patients. The radial AIx is closely associated with aortic calcification, cardiac hypertrophy, and a history of cardiovascular accidents in hemodialysis patients, and could be a useful marker for management of these patients.     

Efficacy of thromboelastography in the management of anticoagulation for veno-venous extracorporeal membrane oxygenation in a coronavirus disease 2019 patient: A case report

Rationale:In coronavirus disease 2019 (COVID-19) patients with acute respiratory distress syndrome refractory to optimal conventional management, we should consider the indication for veno-venous extracorporeal membrane oxygenation (V-V ECMO). Growing evidence indicates that COVID-19 frequently causes coagulopathy, presenting as hypercoagulation and incidental thrombosis. For these reasons, a multifactorial approach with several anticoagulant markers should be considered in the management of anticoagulation using heparin in COVID-19 patients on V-V ECMO.Patient concerns:A 48-year-old man was infected with COVID-19 with a worsening condition manifesting as acute respiratory distress syndrome.Diagnoses:He was refractory to conventional therapy, thus we decided to introduce V-V ECMO. We used heparin as an anticoagulant therapy for V-V ECMO and adjusted the doses of heparin by careful monitoring of the activated clotting time (ACT) and activated partial thromboplastin time (APTT) to avoid both hemorrhagic and thrombotic complications. We controlled the doses of heparin in the therapeutic ranges of ACT and APTT, but clinical hemorrhaging and profound elevation of coagulant marker became apparent.Interventions:Using thromboelastography (TEG; Haemonetics) in addition to ACT and APTT, we were able to clearly detect not only sufficient coagulability of COVID19 on V-V ECMO (citrated rapid thromboelastography-R 0.5 min, angle 75.5°, MA 64.0 mm, citrated functional fibrinogen-MA 20.7 mm) but also an excessive effect of heparin (citrated kaolin -R 42.7 min, citrated kaolin with heparinase 11.7 min).Outcomes:Given the TEG findings indicating an excessive heparin effect, the early withdrawal of ECMO was considered. After an evaluation of the patient''s respiratory capacity, withdrawal from V-V ECMO was achieved and then anticoagulation was stopped. The hemorrhagic complications and elevated thrombotic marker levels dramatically decreased.Lessons:TEG monitoring might be a useful option for managing anticoagulation in COVID-19 patients on V-V ECMO frequently showing a hypercoagulative state and requiring massive doses of heparin, to reduce both hemorrhagic and thrombotic complications.     

The Clara cell10 adenine38guanine polymorphism and sarcoidosis susceptibility in Dutch and Japanese subjects

CC10 (CC16, uteroglobin) is a pulmonary protein postulated to play a counter regulatory role in sarcoidosis pathogenesis. The adenine38guanine (A38G) polymorphism of the encoding CC10 gene (SCGB1A1) is functional. Recently, an association between the low CC10 producing 38A allele and sarcoidosis susceptibility has been reported in Japanese patients from Hokkaido. The aim of the present study was to confirm this association in a clinically well characterized population of Dutch white and Kyoto Japanese patients with sarcoidosis and control subjects. No difference in genotype or allele frequency was found between patients with sarcoidosis and control subjects in either ethnic population. Remarkably, however, a significant difference was found between the control subjects from Kyoto and Hokkaido, but not between the Japanese groups of patients with sarcoidosis. Furthermore, review of previously published A38G genotyping results showed a consistent difference in CC10 A38G allele frequencies between whites and Japanese subjects. We conclude that the CC10 A38G polymorphism does not influence sarcoidosis susceptibility in Dutch whites or in Japanese subjects from Kyoto. This stresses the importance of studying the influence of polymorphisms on disease susceptibility in multiple ethnically and geographically distinct disease and control populations before reaching conclusions.     

Tone-Inhibiting Insoles Enhance the Reciprocal Inhibition of Ankle Plantarflexors of Subjects With Hemiparesis After Stroke: An Electromyographic Study

Background

Spasticity is a common sequela of upper motor neuron pathology, such as cerebrovascular diseases and cerebral palsy. Intervention for spasticity of the ankle plantarflexors in physical therapy may include tone-inhibiting casting and/or orthoses for the ankle and foot. However, the physiological mechanism of tone reduction by such orthoses remains unclarified.

Behavioral intention to prevent cervical cancer and related factors among female high school students in Japan

Aim

This study aimed to examine female high school students’ behavioral intention to prevent cervical cancer and related factors.

Methods

The participants were 2158 female high school students at 16 high schools in A prefecture in the Tohoku region in Japan. A self‐administered questionnaire was carried out that was developed based on a conceptual framework comprising the Health Belief Model and Theory of Reasoned Action.

Results

The responses were obtained from 2072 students (96.0%). Of these, the answers of 2028 respondents were analyzed after excluding those participants who did not complete the behavioral intention item (effective response rate: 97.0%). A factor analysis and covariance structure analysis yielded a model with strong goodness‐of‐fit that explained the behavioral intentions based on an “Awareness of the importance and effectiveness of cervical cancer screening,” “Obstacles to cervical cancer prevention behavior,” “Subjective norms for adopting cervical cancer prevention behavior,” and “The behavior of someone close that encourages cervical cancer prevention behavior.”

Conclusion

The statistical analysis yielded a model with strong goodness‐of‐fit that explained female high school students’ behavioral intentions, which were related to four factors, including “the awareness of the importance and effectiveness of cervical cancer screening.”

     

Knee joint angle and vasti muscle electromyograms during fatiguing contractions

We compared vasti muscle electromyograms for two knee joint angles during fatiguing tetanic contractions. Tetanic contraction of the knee extensors was evoked for 70 s by electrical stimulation of the femoral nerve at knee joint angles of 60° (extended, with 0° indicating full extension) and 110° (flexed) in eight healthy men. Surface electromyography was recorded from the vastus intermedius (VI), vastus lateralis (VL) and vastus medialis (VM) muscles. Knee extension force and M‐wave amplitudes and durations were calculated every 7 s, which were normalized by the initial value. Normalized knee extension force was decreased at the flexed knee joint angle compared with that of the extended knee joint angle (P<0·05). Decreased normalized M‐wave amplitude and increased normalized M‐wave duration of the VI were greater at the flexed knee joint angle than the extended knee joint angle (P<0·05), whereas those for the VL and VM were similar (P>0·05). These results suggest that peripheral fatigue profiles of the VI might be greater at the flexed than the extended knee joint angles, but that of VL and VM might be similar in the tested range of knee joint angles (i.e. 60°–110°) during continuous tetanic contraction induced by electrical stimulation. Therefore, greater reduction of knee extension force at the flexed knee joint angle than the extended knee joint angle may reflect fatigue development of the VI more than other quadriceps femoris components.     

Potential Effect of Prolonged Sevoflurane Anesthesia on the Kinetics of [<Superscript>11</Superscript>C]Raclopride in Non-human Primates

Purpose

Positron emission tomography (PET) in non-human primates (NHP) is commonly performed under anesthesia, with sevoflurane being a widely used inhaled anesthetic. PET measurement in NHP can be repeated, and a difference in radioligand kinetics has previously been observed between the first and second PET measurement on the same day using sevoflurane anesthesia. In this study, we evaluated the effect of prolonged sevoflurane anesthesia on kinetics and binding potential (BP_ND) of [¹¹C]raclopride in NHP.

Procedures

Three cynomolgus monkeys underwent two to three PET measurements with [¹¹C]raclopride under continuous sevoflurane anesthesia on the same day. The concentration of sevoflurane was adjusted according to the general conditions and safety parameters of the NHP. Time to peak (TTP) radioactivity in the striatum was estimated from time-activity curves (TACs). The BP_ND in the striatum was calculated by the simplified reference tissue model using the cerebellum as reference region.

Results

In each NHP, the TTP became shorter in the later PET measurements than in the first one. Across all measurements (n = 8), concentration of sevoflurane correlated with TTP (Spearman’s ρ = ? 0.79, p = 0.03), but not with BP_ND (ρ = ? 0.25, p = 0.55).

Conclusions

These data suggest that sevoflurane affects the shape of TACs but has no evident effect on BP_ND in consecutive PET measurements.