Prevalence of Ventilatory Function Abnormalities in Residents of Attecoube Lagune, Abidjan (Côte d’Ivoire)

Introduction: Studies of abnormal ventilatory function in Côte d’Ivoire have been carried out in the workplace and in schools. The objective of this study was to determine the prevalence of respiratory symptoms and ventilatory function abnormalities in the population of the lagoon district of Attécoubé in Abidjan. Material and Methods: A cross-sectional study was carried out on 170 people in the municipality of Attécoubé Lagune. A questionnaire was used to collect information on sociodemographic, clinical, and environmental characteristics. A basic spirometry and a beta mimetic test were carried out on all the subjects surveyed. Data analysis was done with the stata 15.1 software. Results: The study population was composed of 103 women and 67 men with a sex ratio (M/F) of 0.65. The average age was 35.92 ± 15.28 years. The most frequent respiratory symptoms were chest tightness (29.41%), dyspnea (28.82%), sneezing (22.94%) and cough (22.35%). The prevalence of ventilatory function abnormalities was 43.24% among residents of Attécoubé Lagune and the most frequent abnormality was ventilatory restriction (35.15%) followed by obstruction (4.85%). The risk factor for ventilatory function abnormalities was heavy pollution [OR = 2.66;IC: 1.053 - 6.743;P = 0.038]. Conclusion: Residents of the Attécoubé Lagune district had many respiratory symptoms and a high prevalence of ventilatory function abnormalities. Improving air quality is urgently needed in this municipality.

Heart rate variability to assess ventilatory thresholds in professional basketball players

Purpose: The aim of this study was to determine if heart rate variability(HRV) during incremental test could be used to estimate ventilatory threshold(VT) in professional basketball players, with sufficient precision to be used in their training. Furthermore, the second aim was to analyse the association between HRV and 3 methods of VT determination by gas analysis.Methods: Twenty-four professional basketball players(age: 23.4 ± 4.9 years; height: 195.4 ± 9.8 cm; body mass: 92.2 ± 11.9 kg) performed an incremental running test to exhaustion. First ventilatory threshold(VT1) was determined by ventilatory equivalent(VE) and HRV and second ventilatory threshold(VT2) was determined by 3 methods of gases analysis(V-slope, VE and gas exchange ratio(R), and HRV). Pearson's coefficient(r) was used to detect differences between data and the strength of each relationship. The mean of absolute differences and Bland–Altman analysis were used to evaluate whether there was agreement.Results: The results showed no significant differences in HR and oxygen consumption(VO2) at VT1 between the 2 methods. Furthermore, no significant differences among the methods of gases analysis and HRV were observed in speed, HR, and VO2 at VT2. Moreover, VTs estimated using HRV and gas methods were significantly correlated. Correlation in HR values was higher between R and HRV(r = 0.96) and VE and HRV(r = 0.96) than V-slope and HRV(r = 0.90).Conclusion: These findings provide a practical, inexpensive approach for evaluating specific training loads when determining VT2 in basketball players. Therefore, HRV is an alternative method to determine VT2 without the application of expensive technology that limits its use to laboratories.

Comparison of ventilatory threshold between subjects with and without proteinuria in Japanese

We compared the levels of ventilatory threshold (VT) between subjects with and without pro-teinuria. We used data of 402 men and 413 women who were not taking any medications, aged 20 - 77 years, in this cross-sectional in-vestigation study. Aerobic Parameters at VT i.e. oxygen uptake, work rate and heart rate, and exercise habits were evaluated, which are con-sidered to be cardio respiratory fitness. Pro-teinuria was measured by using urine strip de-vices. Forty three men (10.7%) and 29 women (7.0%) were diagnosed as having the proteinuria (± ≦). There were no significant relationships between proteinuria and exercise habits in both sexes after adjusting for age. Oxygen uptake at VT in subjects with proteinuria was significantly lower than that in subjects without proteinuria after adjusting for age in men. However, such link was not noted in women after adjusting for age (p = 0.9964). Finally, associations were at-tenuated after adjusting for age and exercise habits in both sexes. Among Japanese not tak-ing medications, proteinuria might be a modifi-able factor of VT, especially in Japanese men.

Non-exhaustive double effort test is reliable and estimates the firs ventilatory threshold intensity in running exercise

Purpose: The present study aimed to investigate the reliability of the non-exhaustive double effort(NEDE) test in running exercise and its associations with the ventilatory thresholds(VT_1 and VT_2) and the maximal lactate steady state(MLSS).Methods: Ten healthy male adults(age: 23 ± 4 years, height: 176.6 ± 6.4 cm, body mass: 76.6 ± 10.7 kg) performed 4 procedures:(1) a ramp test for VT_1 and VT_2 determinations measured by ratio of expired ventilation to O_2 uptake(VE/VO_2) and expired ventilation to CO_2 output(VE/VCO_2) equivalents, respectively;(2) the NEDE test measured by blood lactate concentration(NEDE_(LAC)) and heart rate responses(NEDE_(HR));(3) a retest of NEDE for reliability analysis; and(4) continuous efforts to determine the MLSS intensity. The NEDE test consisted of4 sessions at different running intensities. Each session was characterized by double efforts at the same running velocity(E1 and E2, 180 s), separated by a passive recovery period(90 s rest). LAC and HR values after E1 and E2(in 4 sessions) were used to estimate the intensity equivalent to"null delta" by linear fit. This parameter represents, theoretically, the intensity equivalent to maximal aerobic capacity.Results: The intraclass correlation coefficient indicated significant reliability for NEDE_(LAC)(0.93) and NEDE_(HR)(0.79)(both p < 0.05). There were significant correlations, no differences, and strong agreement with the intensities predicted by NEDE_(LAC)(10.1 ± 1.9 km/h) and NEDE_(HR)(9.8 ± 2.0 km/h) to VT_1(10.2 ± 1.1 km/h). In addition, despite significantly lower MLSS intensity(12.2 ± 1.2 km/h), NEDE_(LAC) and NEDE_(HR) intensities were highly correlated with this parameter(0.90 and 0.88, respectively).Conclusion: The NEDE test applied to running exercise is reliable and estimates the VT_1 intensity. Additionally, NEDE intensities were lower but still correlated with VT_2 and MLSS.

Modulation of Respiratory Neural Drive by Physiological Loads in COVID-19 Patients with Dyspnea

COVID-19 patients often experience dyspnea due to several factors. The underlying unique pathophysiology of dyspnea in COVID-19 is not yet fully understood, but it is believed to be related to a combination of respiratory, cardiovascular, and neuromuscular factors. Hypoxemia is considered one of the key symptoms of COVID-19. This affects the respiratory drive, which determines the rate, depth, and pattern of breathing. The relationship between increased ventilatory neural drive and abnormal gas exchange, particularly in the context of ventilation/perfusion (V/Q) mismatches and chemosensitivity, has gained significant attention following the COVID-19 pandemic. The ACE2 receptors allow viral entry into the lungs, leading to the loss of surfactant, hypoxic vasoconstriction, and intrapulmonary shunting that may result in a V/Q mismatch. Additionally, acidosis, hypercapnia, elevated 2,3-diphosphogly-cerate levels and fever may shift the oxygen diffusion curve rightward, lowering arterial oxygen saturation levels and triggering ventilatory responses. This paper examines how physio pathological factors such as altered gas diffusion, chemosensory feedback, V/Q ratios, altered compliance, arterial blood gases, and respiratory muscle dysfunction in these patients affect ventilatory drive. A review of the published literature was also conducted to determine the mechanism of dyspnea. To ensure appropriate gas exchange, individuals need to augment their minute ventilation (VE) when physiological dead space is elevated. This serves as a compensatory mechanism to counteract the effects of compromised gas exchange and keep adequate oxygenation throughout the body. The respiratory centers may experience dysregulation due to the impact of the virus on the respiratory system, which could affect the rhythm-generating and pattern-generating signals that are vital for regulating the respiratory rate and depth of breathing effort. The cerebral cortex, in conjunction with the brain stem centers, plays a crucial role in regulating ventilation during prolonged hypoxemia. This interaction between these two components may help elucidate the conscious respiratory sensation (or dyspnea) experienced by patients. It is hypothesized that neuroventilatory decoupling acts as a mechanism to prevent sensory signals from translating into mechanical or ventilatory responses. This decoupling phenomenon is believed to have a notable impact on the intensity of breathlessness. By understanding the relationship between increased ventilatory neural drive and abnormal gas exchange, particularly in the context of ventilation/perfusion (V/Q) mismatches and altered chemosensitivity, healthcare professionals can develop strategies to optimize respiratory support for COVID-19 patients.

Is there an acute exercise-induced physiological/biochemical threshold which triggers increased speed of cognitive functioning? A meta-analytic investigation

Purpose： The purpose of this study was to examine, using meta-analytic measures, the evidence regarding the optimal exercise intensity at which improvements in speed of cognitive function are triggered. Specifically, it was hypothesized that the catecholamine, lactate, and ventilatory thresholds is the point at which significant improvements in speed of cognitive function are observed. Methods： We compared mean effect sizes for threshold studies and for those studies where exercise intensity was classed as moderate （40%-- 79% VO2 or equivalent） but in which the thresholds were not measured. Results： Random effects meta-analysis showed significant, moderate, mean effect sizes for studies at the threshold （g = 0.58, Z = 2.98, p 〈 0.003） and for those during moderate intensity exercise but in which the threshold was not measured （ g = 0.54, Z = 5.0l, p 〈 0.001）. There was no significant difference between mean effect sizes, which suggests that the thresholds are unlikely to represent a trigger point. Conclusion： Moderate intensity exercise, even below the thresholds, can induce improved speed of cognition, possibly due to a combination of increased peripheral catecholamine concentrations inducing vagal/nucleus tractus solitarii pathway activation and central increases due to perceptions of stress.

Anesthetic management and associated complications of peroral endoscopic myotomy:A case series

AIM To investigate the anesthetic management of peroral endoscopic myotomy(POEM) and its associated complications.METHODS This study was a single-center,retrospective,observational study comprising a case series of all patients who underwent POEM in our hospital from April 2015 to November 2016.We collected data regarding patient characteristics,anesthetic methods,surgical factors,and complications using an electronic chart.RESULTS There were 86 patients who underwent POEM in our hospital during the study period.Preoperatively,patients were maintained on a low residue diet for 48 h prior to the procedure.They were fasted of solids for 24 h before surgery.There was one case of aspiration(1.2%).During POEM,patients were positioned supine with the upper abdomen covered by a clear drape so that pneumoperitoneum could be timeously identified.In three cases,the peak airway pressure exceeded 35 cm H2 O during volume controlled ventilation with tidal volumes of 6-8 m L/kg and subsequent impairment of ventilation.These cases had been diagnosed with spastic esophageal disorders(SEDs) and the length of the muscular incision on the esophageal side was longer than normal.CONCLUSION In the anesthetic management of POEM,it is important to prevent aspiration during induction of anesthesia and to identify and treat complications associated with CO_2 insufflation.

What is the most effective exercise protocol to improve cardiovascular fitness in overweight and obese subjects？

Background: Increased peak oxygen consumption(VO2 peak) can reduce cardiovascular risks associated with obesity. Our aim was to analyze the effect of a weight loss program on cardiovascular fitness in overweight(W) and obese(O) subjects.Methods: One hundred and sixty-seven subjects(77 males and 90 females), aged 18–50 years, performed a modified Bruce protocol before(pre)and after(post) a weight loss program of 24 weeks. This program combined physical training(strength, S; endurance, E; combined strength + endurance, SE; or physical activity recommendation, PA) 3 times per week, with a 25%–30% caloric restriction diet.Results: VO2 peak improved in overweight and obese males(pre and post values in L/min, respectively; W = 3.2 ± 0.6 vs. 3.7 ± 0.5, p < 0.001;O = 3.6 ± 0.6 vs. 3.8 ± 0.6, p = 0.013) as well as in overweight females(2.0 ± 0.3 vs. 2.3 ± 0.4, p < 0.001). VO2 peak in the first ventilatory threshold(VT1) increased for all 4 interventions in males(p < 0.05), except for S in the obese group(1.6 ± 0.2 vs. 1.7 ± 0.3, p = 0.141). In females, it increased in E(0.9 ± 0.2 vs. 1.4 ± 0.3, p < 0.001), SE(0.9 ± 0.2 vs. 1.2 ± 0.4, p = 0.003), and PA(0.9 ± 0.1 vs. 1.2 ± 0.2, p = 0.006) in overweight groups. Time-to-exhaustion improved in all subjects except for females in PA group(15.7 ± 0.3 min vs. 15.9 ± 0.3 min, p = 0.495).Conclusion: Our results suggest that all methods, including the recommendation of physical activity, can improve cardiovascular fitness in overweight subjects and obese males.

Neurally adjusted ventilator assist in very low birth weight infants:Current status

Continuous improvements in perinatal care have resultedin increased survival of premature infants.Their immature lungs are prone to injury with mechanical ventilation and this may develop into chronic lung disease(CLD) or bronchopulmonary dysplasia.Strategies to minimize the risk of lung injury have been developed and include improved antenatal management(education,regionalization,steroids,and antibiotics),exogenous surfactant administration and reduction of barotrauma by using exclusive or early noninvasive ventilatory support.The most frequently used mode of assisted ventilation is pressure support ventilation that may lead to patientventilator asynchrony that is associated with poor outcome.Ventilator-induced diaphragmatic dysfunction or disuse atrophy of diaphragm fibers may also occur.This has led to the development of new ventilation modes including neurally adjusted ventilatory assist(NAVA).This ventilation mode is controlled by electrodes embedded within a nasogastric catheter which detect the electrical diaphragmatic activity(Edi) and transmit it to trigger the ventilator in synchrony with the patient's own respiratory efforts.This permits the patient to control peak inspiratory pressure,mean airway pressure and tidal volume.Back up pressure control(PC) is provided when there is no Edi signal and no pneumatic trigger.Compared with standard conventional ventilation,NAVA improves blood gas regulation with lower peak inspiratory pressure and oxygen requirements in preterm infants.NAVA is safe mode of ventilation.The majority of studies have shown no significant adverse events in neonates ventilated with NAVA nor a difference in the rate of intraventricular hemorrhage,pneumothorax,or necrotizing enterocolitis when compared to conventional ventilation.Future large size randomized controlled trials should be established to compare NAVA with volume targeted and pressure controlled ventilation in newborns with mature respiratory drive.Most previous studies and trials were not sufficiently large and did not include longterm patient oriented outcomes.Multicenter,randomized,outcome trials are needed to determine whether NAVA is effective in avoiding intubation,facilitating extubation,decreasing time of ventilation,reducing the incidence ofCLD,decreasing length of stay,and improving long-term outcomes such as the duration of ventilation,length of hospital stay,rate of pneumothorax,CLD and other major complications of prematurity.In order to prevent barotrauma,next generations of NAVA equipment for neonatal use should enable automatic setting of ventilator parameters in the backup PC mode based on the values generated by NAVA.They should also include an upper limit to the inspiratory time as in conventional ventilation.The manufacturers of Edi catheters should produce smaller sizes available for extreme low birth weight infants.Newly developed ventilators should also include leak compensation and high frequency ventilation.A peripheral flow sensor is also essential to the proper delivery of all modes of conventional ventilation as well as NAVA.

Acknowledgment to reviewers—November 2016 to October 2017

The Editors of the Journal of Sport and Health Science （JSHS） wish to thank the following people, and any other reviewer whose name has been inadvertently omitted, for giving your time and expertise to review papers and facilitate the smooth running of JSHS between November 2016 and October 2017.

Prognostic Value of Cardiopulmonary Exercise Test in Elderly Women with Heart Failure and Reduced or Preserved Ejection Fraction

The prognostic role of cardiopulmonary exercise test (CPET) in elderly women with chronic heart failure (HF) has not yet been clarified. We assessed the incremental value of CPET variables for risk stratification in female HF patients with preserved or reduced left ventricular ejection fraction (LVEF). We prospectively followed up 131 female HF outpatients aged 72 [interquartile range 62 - 77] years after a symptom limited CPET. 34% had ischemic heart disease and 14% permanent atrial fibrillation, 24% were in NYHA class III. LVEF was 50% [interquartile range 36 - 62], peak oxygen consumption was 11.3 [interquartile range 9.2 - 13.5] ml/kg/min;the slope of the regression line relating ventilation to CO2 output was 33.9 [interquartile range 30.3 - 44.9];40% of patients showed exercise oscillatory breathing during CPET. During a median follow-up of 18 months [interquartile range 8 - 54], overall 39 patients (29.7%) met the combined end-point of cardiovascular mortality or HF admission using a time-to-first event approach. Moderate to severe mitral regurgitation, slope, exercise oscillatory breathing were independently associated to cardiovascular mortality or HF admission. When CPET ventilatory variables were added to clinical and echocardiographic parameters, prediction of the combined point improved significantly (AUC 0.755 (95% CI 0.662 to 0.832) vs 0.634 (95% CI 0.536 to 0.725), p = 0.016). In conclusion, among elderly female HF patients the CPET derived parameters EOB and VE/VCO2 slope emerged as strong prognostic markers, with additive predictive value to clinical and echocardiographic parameters in patients with both reduced and preserved LVEF.

Predictors of 2 Kilometer Rowing Ergometer Time Trial Performance

Predictors of performance can aid coaches and trainers in prescribing exercise programs for rowing athletes. To date, most of the prediction models have been developed for runners and cyclists. Purpose: The aim of this study was to develop a regression model to predict performance of a simulated 2 kilometer rowing ergometer time trial. Methods: A group of mixed gender rowing athletes (n = 12) completed in a counterbalanced order a 2 kilometer rowing time trial and a continuous progressively incremented graded exercise test on a rowing ergometer. Subjects were 23.91 ± 4.99 years old, weighed 79.14 ± 12.85 kg, were 187.38 ± 12.60 cm, had a VO2max of 55.48 ± 10.32 mL/kg/min and had 3.17 ± 2.79 years of rowing experience. Physiological measures were recorded during both testing protocols. Results: Maximum power/stroke ratio (r =-0.96, p < 0.001), power/stroke ratio at the ventilatory breakpoint (r =-0.90, p < 0.001), maximal oxygen uptake (r =-0.84, p < 0.001) and oxygen uptake at the ventilatory breakpoint (r =-0.82, p < 0.001) were found to be strong and significant predictors of 2 kilometer rowing performance. Conclusion: The four significant predictors of rowing performance suggest training should focus on improving both aerobic capacity and strength. Practical Application: Rowing training should focus on developing hip and leg aerobic and anaerobic capacities to improve performance. Developing strength improves mechanical efficiency as well as raising anaerobic thresholds allowing athletes to utilize a larger portion of their aerobic capacity.

Carbon dioxide:Global warning for nephrologists

The large prevalence of respiratory acid-base disordersoverlapping metabolic acidosis in hemodialysis popu-lation should prompt nephrologists to deal with the partial pressure of carbon dioxide （pCO2） complying with the reduced bicarbonate concentration. What the most suitable formula to compute pCO2 is reviewed. Then, the neglected issue of CO2 content in the dialysis fluid is under the spotlight. In fact, a considerable amount of CO2 comes to patients’ bloodstream every hemodialysis treatment and “acidosis by dialysate” may occur if lungs do not properly clear away this burden of CO2. Moreover, vascular access recirculation may be easy diagnosed by detecting CO2 in the arterial line of extracorporeal circuit if CO2-enriched blood from the flter reenters arterial needle.

Non-Invasive Positive Pressure Ventilation (NIPPV) in the Pregnant Patient: A Case Series

Rationale: Acute respiratory failure is an uncommon complication of pregnancy. However, it is the most frequent organ dysfunction associated with obstetric admissions to an intensive care unit. The obstetric population is a different group due to its physiology and the presence of the fetus that lacks evidence in the literature within the subject of ventilatory support. Noninvasive positive pressure ventilation (NIPPV) is often avoided due to the lack of knowledge on the safety and efficacy of this modality. Currently, there are no guidelines for the management of respiratory failure in pregnancy. Objectives: To provide evidence in support of the use of NIPPV as a safe and reasonable modality for pregnant patients with respiratory failure. Methods: We retrospectively reviewed medical records of 29 pregnant patients of the Obstetric Critical Care Unit of a tertiary hospital in Panamá City who received NIPPV from 2013 to 2015. Failure to response was defined as the lack of increase in the paO2/FiO2 ratio or clinical deterioration 6 hours after initiating NIPPV. Demographics, indication for NIPPV, duration of treatment, as well as maternal and fetal outcomes were collected. Measurements and Main Results: Mean age was 28.4 ± 6 years, mean body mass index 27.4 ± 3.3, and mean gestational age at admission was 305/7 ± 5 weeks. Twenty-four patients (82.8%) met the criteria for acute lung injury (ALI) and an additional two (6.9%) for acute respiratory distress syndrome (ARDS). The mean duration of ventilation was 50.6 ± 17.27 hours. Statistically significant differences were noted between the paO2/FiO2 ratios in failure and successful patients within 2 hours of NIPPV therapy (P = 0.007) and paO2/FiO2 ratio within 6 hours of NIPPV therapy (P = 0.03). Success was defined when the patient was administered NIPPV, resulting in an improvement (increase in pa/FiO2 ratio) of her ventilatory parameters. Three patients (10.3%) failed to respond to NIPPV and needed to be converted to invasive mechanical ventilation. Patients who required intubation had a longer duration of ICU stay (P = 0.006) and overall hospital stay (P = 0.03). None of patients presented aspiration during NIPPV therapy. Conclusion: The current series is the largest report of pregnant patients requiring ventilatory support who received NIPPV as first line of therapy. This report shows the usefulness of this ventilation modality, avoiding intubation with its risks, of a significant number of patients, especially ventilator-associated pneumonia.

Respiratory Morbidity Associated with Long-Term Occupational Inhalation Exposure to High Concentrations of Hydrated Calcium Sulfate Dust

Despite wide application of hydrated calcium sulfate, possible respiratory effects of long-term occupational exposure to high concentrations of this chemical have only been investigated in a limited number of epidemiological studies. This study is undertaken to examine this issue, more thoroughly. This cross-sectional study is carried out at a local gypsum plant in Shiraz, capital of Fars province situated in south western Iran. All exposed subjects (20 male workers) and 20 healthy non-exposed male individuals as the referent group are investigated. Prevalence of respiratory symptoms among the studied subjects is evaluated and they undergo spirometry test (twice for the exposed group and once for the unexposed employees). Moreover, to assess the extent to which workers are exposed to gypsum dust and using standard methods, inhalable and respirable fractions of this compound are measured in different dusty worksites. Average airborne concentration of inhalable dust fraction is estimated to be 24 ± 14.76 mg/m3 which is higher than the recommended threshold limit value (TLV) for this chemical. Respiratory symptoms such as phlegm, wheezing and dyspnea are significantly more prevalent in exposed subjects than in non-exposed employees (p < 0.05). The results of ventilatory function tests (pre- shift) don’t show any significant differences between both groups. However, some post-shift parameters of ventilatory function such as FVC, FEV1 and FEV1/FVC ratio are significantly lower than those of preshift and referent group. Exposure to high atmospheric concentrations of gypsum dust is associated with a significant increase in the prevalence of respiratory symptoms along with acute reversible significant decreases in some parameters of ventilatory function.

Dead Space Breathing in Patients with Malignancies: Determination by Cardiopulmonary Exercise Testing

Rationale: Patients with cancer commonly experience dyspnea originating from ventilatory, circulatory and musculoskeletal sources, and dyspnea is best determined by cardiopulmonary exercise testing (CPET). Objectives: In this retrospective pilot study, we evaluated patients with hematologic and solid malignancies by CPET to determine the primary source of their dyspnea. Methods: Subjects were exercised on a cycle ergometer with increasing workloads. Minute ventilation, heart rate, breathing reserve, oxygen uptake (V’O2), O2-pulse, ventilatory equivalents for carbon dioxide and oxygen (V’E/V’CO2 and V’E/V’O2, respectively) were measured at baseline and peak exercise. The slope and intercept for V’E/V’CO2 was computed for all subjects. Peak V’O2 4% predicted indicated a circulatory or ventilatory limitation. Results: Complete clinical and physiological data were available for 36 patients (M/F 20/16);32 (89%) exhibited ventilatory or circulatory limitation as shown by a reduced peak V’O2 and 10 subjects with normal physiologic data. The largest cohort comprised the pulmonary vascular group (n = 18) whose mean ± SD peak V’O2 was 61% ± 17% predicted. There were close associations between V’O2 and spirometric values. Peak V’E/V’O2 and V’E/V’CO2 were highest in the circulatory and ventilatory cohorts, consistent with increase in dead space breathing. The intercept of the V’E-V’CO2 relationship was lowest in patients with cardiovascular impairment. Conclusion: Dyspneic patients with malignancies exhibit dead space breathing, many exhibiting a circulatory source for exercise limitation with a prominent pulmonary vascular component. Potential factors include effects of chemo- and radiation therapy on cardiac function and pulmonary vascular endothelium.

Respiratory Control by Phox2b-expressing Neurons in a Locus Coeruleus–pre B?tzinger Complex Circuit

The locus coeruleus(LC) has been implicated in the control of breathing.Congenital central hypoventilation syndrome results from mutation of the paired-like homeobox 2 b(Phox2 b) gene that is expressed in LC neurons.The present study was designed to address whether stimulation of Phox2 b-expressing LC(Phox2 b~(LC)) neurons affects breathing and to reveal the putative circuit mechanism.A Cre-dependent viral vector encoding a Gqcoupled human M3 muscarinic receptor(hM3 Dq) was delivered into the LC of Phox2 b-Cre mice.The hM3 Dqtransduced neurons were pharmacologically activated while respiratory function was measured by plethysmography.We demonstrated that selective stimulation of Phox2 b~(LC) neurons significantly increased basal ventilation in conscious mice.Genetic ablation of these neurons markedly impaired hypercapnic ventilatory responses.Moreover,stimulation of Phox2 b~(LC) neurons enhanced the activity of preBotzinger complex neurons.Finally,axons of Phox2 b~(LC) neurons projected to the preBotzinger complex.Collectively,Phox2 b~(LC) neurons contribute to the control of breathing most likely via an LC-preBotzinger complex circuit.

Clinical evaluation of physical fitness in male obese Japanese

:Objective To establish an effective exercise prescription, the exercise capacity of obese subjects was investigated.Methods In 71 male obese (body mass index: BMI≥26.4) Japanese, aged 26-77 years, the body composition and physical fitness such as aerobic exercise level, muscle strength and flexibility were determined and compared with those of age- and sex-matched 71 borderline (24.2≤BMI<26.4) and 71 normal Japanese men (19.8≤BMI<24.2). The relationship between body composition and other parameters was evaluated in obese subjects.Results In obese subjects, body weight, BMI, body fat percentage, waist hip ratio, and skinfold thickness were higher than those of borderline and normal subjects. Lower aerobic exercise level and weight bearing index (WBI) were noted in obese subjects. There was a negative correlation between waist hip ratio and aerobic exercise level (oxygen uptake at ventilatory threshold) (r=-0.509, P<0.01) and also between waist hip ratio and WBI (r=-0.315, P<0.01). Conclusions Lower physical fitness is considered to be a general characteristic of male obese Japanese, and the accumulation of visceral adipose tissue might affect exercise capacity.

Inwardly rectifying potassium channel 5.1:Structure,function,and possible roles in diseases

Inwardly rectifying potassium(Kir)channels make it easier for K^(+)to enter into a cell and subsequently regulate cellular biological functions.Kir5.1(encoded by KCNJ16)alone can form a homotetramer and can form heterotetramers with Kir4.1(encoded by KCNJ10)or Kir4.2(encoded by KCNJ15).In most cases,homomeric Kir5.1 is non-functional,while hetero-meric Kir5.1 on the cell membrane contributes to the inward flow of K^(+)ions,which can be regulated by intracellular pH and a variety of signaling mechanisms.In the form of a heterotetramer,Kir5.1 regulates Kir4.1/4.2 activity and is involved in the maintenance of nephron function.Actually,homomeric Kir5.1 may also play a very important role in diseases,including in the ventilatory response to hypoxia and hypercapnia,hearing impairment,cardio-vascular disease and cancer.With an increase in the number of studies into the roles of Kir channels,researchers are paying more attention to the pathophysiological functions of Kir5.1.This minireview provides an overview regarding these Kir5.1 roles.