Function In Healthy Volunteers Research Articles

Acute Effects of Electronic Cigarette Inhalation on the Vasculature and the Conducting Airways

The use of electronic cigarettes has increased exponentially since its introduction onto the global market in 2006. However, short- and long-term health effects remain largely unknown due to the novelty of this product. The present study examines the acute effects of e-cigarette aerosol inhalation, with and without nicotine, on vascular and pulmonary function in healthy volunteers. Seventeen healthy subjects inhaled electronic cigarette aerosol with and without nicotine on two separate occasions in a double-blinded crossover fashion. Blood pressure, heart rate, and arterial stiffness measured by pulse wave velocity and pulse wave analysis were assessed at baseline, and then at 0 h, 2 h, and 4 h following exposure. Dynamic spirometry and impulse oscillometry were measured following vascular assessments at these time points, as well as at 6 h following exposure. e-Cigarette aerosol with nicotine caused a significant increase in heart rate and arterial stiffness. Furthermore, e-cigarette aerosol-containing nicotine caused a sudden increase in flow resistance as measured by impulse oscillometry, indicating obstruction of the conducting airways. Both aerosols caused an increase in blood pressure. The present study indicates that inhaled e-cigarette aerosol with nicotine has an acute impact on vascular and pulmonary function. Thus, chronic usage may lead to long-term adverse health effects. Further investigation is warranted.

Effect of cocoa on the brain and gut in healthy subjects: a randomised controlled trial.

Dark chocolate is claimed to have effects on gastrointestinal function and to improve well-being. This randomised controlled study tested the hypothesis that cocoa slows gastric emptying and intestinal transit. Functional brain imaging identified central effects of cocoa on cortical activity. Healthy volunteers (HV) ingested 100 g dark (72 % cocoa) or white (0 % cocoa) chocolate for 5 d, in randomised order. Participants recorded abdominal symptoms and stool consistency by the Bristol Stool Score (BSS). Gastric emptying (GE) and intestinal and colonic transit time were assessed by scintigraphy and marker studies, respectively. Combined positron emission tomography-computed tomography (PET-CT) imaging assessed regional brain activity. A total of sixteen HV (seven females and nine males) completed the studies (mean age 34 (21-58) years, BMI 22·8 (18·5-26·0) kg/m2). Dark chocolate had no effect on upper gastrointestinal function (GE half-time 82 (75-120) v. 83 (60-120) min; P=0·937); however, stool consistency was increased (BSS 3 (3-5) v. 4 (4-6); P=0·011) and there was a trend to slower colonic transit (17 (13-26) v. 21 (15-47) h; P=0·075). PET-CT imaging showed increased [18F]fluorodeoxyglucose (FDG) in the visual cortex, with increased FDG uptake also in somatosensory, motor and pre-frontal cortices (P<0·001). In conclusion, dark chocolate with a high cocoa content has effects on colonic and cerebral function in HV. Future research will assess its effects in patients with functional gastrointestinal diseases with disturbed bowel function and psychological complaints.

Effects of β-Fructans Fiber on Bowel Function: A Systematic Review and Meta-Analysis.

The aim of this systematic review and meta-analysis was to assess the effects of β-fructan supplementation on bowel function in healthy volunteers and patients. The search process was based on the selection of publications listed in the Pubmed and EUPMC database until December 2017, plus two unpublished studies, to identify studies evaluating the impact of β-fructans on bowel movement and stool parameters. Forty-seven publications were selected for inclusion. Primary parameter was frequency of bowel movements, evaluated by the number of defecations per day during the study period. Secondary outcomes were stool consistency, stool dry and wet weights, and transit time. Short-chain (DP < 10) β-fructans contributed to increased stool frequency (0.36 defecation +/− 0.06 per day; p < 0.001), while no significant effect was reported with long-chain (DP ≥ 10) β-fructans (−0.03 +/− 0.11, p = 0.82). A minimal increase in stool wet weight was also statistically demonstrated with short-chain β-fructans. Moreover, the meta-analysis highlighted significant differences in stool consistency in contrast to fecal dry weight after β-fructan supplementation. This systematic review and meta-analysis indicates that short-chain β-fructan supplementation has a positive effect on bowel function by significantly increasing the frequency of bowel movements.

Acute effects of electronic and tobacco cigarettes on vascular and respiratory function in healthy volunteers: a cross-over study.

To assess the acute effects of nicotine-containing electronic cigarettes versus tobacco smoking on vascular and respiratory function and circulating microparticles, particularly platelet microparticles (PMPs, biomarker of haemostasis/thrombosis) and endothelial microparticles (EMPs, biomarker of endothelial function). Heart rate (HR), blood pressure, reactive hyperaemia index (RHI, microvascular reactivity), augmentation index (arterial stiffness) and respiratory function were assessed in 20 smokers immediately before and after electronic cigarettes use and tobacco smoking. The number of microparticles was determined by flow cytometry using counting beads as a reference. Labelling with Annexin-V was used to detect the total microparticle fraction. EMPs were characterized as CD31+CD42- and PMPs as CD31+CD42+. HR increased after electronic cigarettes use and tobacco smoking (P < 0.001), whereas blood pressure remained unchanged (P > 0.05). RHI (P = 0.006), augmentation index (P = 0.010) but not augmentation index standardized to HR 75 bpm (P > 0.05) increased with electronic cigarettes use but not with tobacco smoking. Following tobacco smoking, there was a significant increase in total microparticles (P < 0.001), EMPs (P < 0.001) and PMPs (P < 0.001). In contrast, electronic cigarettes were only associated with an increase in PMPs (P < 0.001), with no significant changes in the total microparticle fraction or EMPs (all P > 0.05). Peak expiratory flow significantly decreased following electronic cigarettes use (P = 0.019). Our results demonstrate that acute exposure to tobacco smoking as well as electronic cigarettes influences vascular and respiratory function. Where tobacco smoking significantly increased microparticle formation, indicative of possible endothelial injury, electronic cigarettes use induced vasoreactivity and decreased peak expiratory flow. These findings suggest that both electronic cigarettes and tobacco smoking negatively impact vascular function.

Oxytocin reactivity to an emotional challenge paradigm and its relation to social-cognitive functions in healthy volunteers.

The neuropeptide oxytocin (OT) is known to be an important modulator of social cognition. It has been shown that lower OT plasma concentrations are linked to impairments in social cognition. Studies have also shown that intranasal OT may enhance social-cognitive abilities in healthy subjects. We hypothesize that, besides baseline OT concentrations, the reactivity of the OT system may have an important role in social-cognitive functioning of individuals. In the present study, we explored if an emotional challenge paradigm is suitable to elicit OT release into plasma to make the reactivity of the OT system measurable. Therefore, 20 healthy male volunteers watched an emotional film clip, showing another person in pain during a severe dentist's treatment, while blood draws were conducted pre and post challenge. OT concentrations in plasma were measured by ELISA after solid phase extraction from plasma. OT plasma concentrations at baseline were significantly negatively correlated to an empathetic rating of our film clip and to measures of emotional empathy for positive and negative emotions, whereas the difference between post-challenge value and baseline was significantly positively correlated with the latter measures. Our data thus show that a short emotional video can be successfully employed as a challenge paradigm for eliciting an increase of peripheral OT in healthy male subjects. Calculating the relative OT change post- vs. pre-challenge may give a measure of OT reactivity. The combination of low peripheral OT at baseline with high OT reactivity may be a psychoendocrine trait that is linked to higher emotional functioning.

Ciprofloxacin in critically ill subjects: considering hepatic function, age and sex to choose the optimal dose.

Pathophysiological changes often result in altered pharmacokinetics of ciprofloxacin in critically ill patients. Although ciprofloxacin clearance (CLCIP) substantially depends on kidney function in healthy volunteers, its relationship to measured creatinine clearance (CLCRM) is weak in critically ill patients. To assess the need for dose reductions in isolated or combined kidney and liver dysfunction in critically ill patients and to re-evaluate relationships between kidney parameters, demographics and ciprofloxacin pharmacokinetics. A population pharmacokinetic model was developed based on 444 ciprofloxacin serum concentrations from 15 critically ill patients with severe infections. CLCIP relationships to parameters reflecting hepatic function, CLCRM, Cockcroft-Gault creatinine clearance (CLCRCG), serum creatinine, sex, weight and age were explored. A simulation study was conducted to integrate knowledge from the new and previously published models. Total bilirubin was identified as a hepatic parameter with a clear relationship to CLCIP. A significant relationship between CLCIP and CLCRCG could be attributed to age and sex only. CLCIP was not associated with CLCRM. The predicted risk of potential overexposure (AUC > 250 mg·h/L) was low even with 1200 mg/day ciprofloxacin daily for patients with reduced CLCRCG (<30 mL/min: risk of 0.7%), while the risk was remarkably higher in elderly female patients with elevated bilirubin (risk of about 20% for 65-year-old women with total bilirubin of 4 mg/dL). Bilirubin, age and sex should be considered to assess the need for dose reductions. For MICs ≤0.25 mg/L, it might be appropriate to reduce the dose to 400 mg/day for elderly female subjects with high bilirubin.

Effect of single caffeine intake on neuropsychological functions in healthy volunteers: A double-blind placebo-controlled study.

ObjectiveWe investigated the effects of a single instance of caffeine intake on neurocognitive functions and driving performance in healthy subjects using an established cognitive battery and a driving simulator system.MethodsThis study was conducted in a double-blind, randomized, placebo-controlled manner from February 19, 2016 to August 6, 2016. Caffeine intake was discontinued 3 days prior to the study. Participants were randomly assigned to receive 200-mg doses of caffeine or a placebo. Thirty minutes after administration, cognitive functions were evaluated via the Symbol Digit Coding Test (SDC), the Stroop Test (ST), the Shifting Attention Test (SAT) and the Four Part Continuous Performance Test (FPCPT). After the cognitive function tests were conducted, driving performance was evaluated using a driving simulator. We measured the brake reaction time (BRT) in the Harsh-braking test and the standard deviation of the lateral position (SDLP) in the Road-tracking test.ResultsOf 100 randomized subjects, 50 (50%) of 100 in the caffeine group and 50 (50%) of 100 in the placebo group completed the study. Participants in the caffeine group had more correct responses than participants in the placebo group on the SAT (P = 0.03) and made fewer errors (P = 0.02). Participants in the caffeine group exhibited shorter times in the Harsh-braking test than participants in the placebo group (P = 0.048).ConclusionsA single instance of caffeine intake changed some neurocognitive functions and driving performance in healthy volunteers.Trial registrationUMIN000023576.

Automated determination of sublingual microcirculatory function in healthy volunteers

Automated determination of sublingual microcirculatory function in healthy volunteers

Evaluation of comfort associated with the use of a robotic mattress with an interface pressure mapping system and automatic inner air-cell pressure adjustment function in healthy volunteers

Aim of the studyA robotic mattress equipped with an interface pressure mapping system and an automatic inner air-cell pressure adjustment function had been developed to aid in the management of pressure ulcers, but its effects on comfort remained unclear. The present study aimed to investigate whether use of the mattress with continuous, automatic, interface pressure mapping-based regulation of inner air-cell pressure (i.e., robotic mattress) improves comfort over that provided by body weight-based pressure regulation (traditional approach) in healthy volunteers. Materials and methodsA robotic mattress was used with two settings (i.e., interface pressure-vs. body weight-based regulation). First, 20 healthy volunteers were recruited, and the level of comfort, interface pressure distribution, body immersion, and tissue oxygenation were measured and compared between the two settings. ResultsThe level of comfort (20.5 vs 47.5, p = 0.014), contact area (2263.9 vs 2145.2 cm2, p = 0.002), and body immersion for healthy participants were significantly larger when using the interface pressure-based setting. ConclusionThe robotic mattress provided improved comfort, which might be caused by increased contact area, and improved body immersion. The robotic mattress is expected to be effective both for managing pressure ulcers and increasing comfort.

The Effect of Prefrontal Transcranial Direct Current Stimulation on Attention Network Function in Healthy Volunteers

The effect of acute transcranial direct current stimulation (tDCS) on cortical attention networks remains unclear. We examined the effect of 20 min of 2 mA dorsolateral prefrontal cortex tDCS (bipolar balanced montage) on the efficiency of alerting, orienting and executive attention networks measured by the attention network test. A between-subjects stratified randomized design compared active tDCS vs. sham tDCS on attention network function in healthy young adults. Executive attention was greater following active vs. sham stimulation (d = 0.76) in the absence of effects on alerting, orienting, or global RT or error rates. Group differences were not moderated by state-mood. Twenty minutes of active 2 mA tDCS over left DLPFC is associated with greater executive attention in healthy humans.

Short-term effects of non-invasive ventilation on cerebral blood flow and cognitive function in COPD

ObjectivesInvestigate the acute effects of non-invasive ventilation (NIV) on cerebral blood flow (CBF) and on cognitive functions in COPD. MethodsNine non-hypercapnic stable COPD and twelve healthy controls were enrolled. CBF (transcranial Doppler), cognitive tests and cardiorespiratory response were performed at baseline, during one hour of NIV and after 30 min. ResultsBoth groups had an increase in tidal volume and reduction in respiratory rate during NIV, but only controls showed PaCO2 reductions (41.2 ± 4.6 to 36.5 ± 7.3 in controls vs. 40.9 ± 4.5 to 42.9 ± 5.9 in COPD). During NIV CBF was significantly reduced in healthy controls and COPD, although this effect was less pronounced in the latter. At the same time, healthy controls demonstrated an improvement in cognitive executive function compared to COPD in the Trail Making Test part B (90.5 vs. 180s; respectively). ConclusionNIV application for one hour reversibly reduced CBF in healthy controls and non-hypercapnic stable COPD patients, despite no significant reductions of the PaCO2 in the latter group. It was associated with minor cognitive improvements in the executive function in healthy volunteers, but not in COPD.

Sa1092 - The Effect of an Osteopathic Intervention on the Respiratory Diaphragm on Lower Esophageal Spincter Function in Healthy Volunteers and Patients with Nonerosive Reflux Disease

Sa1092 - The Effect of an Osteopathic Intervention on the Respiratory Diaphragm on Lower Esophageal Spincter Function in Healthy Volunteers and Patients with Nonerosive Reflux Disease

Microvascular function in healthy volunteers; a comparison of manually and automatically derived measurements

Microcirculatory dysfunction plays a significant role in the pathophysiology of critical illness, including sepsis, haemorrhage and cardiogenic shock. Studies have used video microscopic measurements of the sublingual microcirculation in acute illness, but the clinical utility of these techniques are limited by the need for time-consuming analysis that precludes near-patient data interpretation. The newest video microscopes use Incident Dark Field (IDF) illumination technology (see below) with automated analysis. However the automated analysis has not been validated and there are no data on normal ranges in healthy individuals. This limits the potential application of IDF video microscopy for microcirculation research. This study aims to examine the feasibility and accuracy of measurement of sublingual microvascular function in the awake individual establish the summary statistics of different sublingual microvascular measurements and compare these measurements in three age groups; 18–34 yrs, 35–54 yrs and over 54 yrs. Additionally, this study will correlate the automatically derived measurements of microcirculatory function in comparison to the current gold-standard of manual analysis. An observational study of 150 healthy volunteers, which will include the recording of basic physiological data, medical and drug history, followed by an assessment of the sublingual microvascular bed using CytoCam incident dark field microscopy to measure total vessel density (TVD), perfused vessel density (PVD), and microvascular flow index (MFI). Analysis using current gold standard manual analysis with automated analysis using CytoCam Tool 1.7 (Braedius Medical BV) Analysis plan: (a.) Computation of summary statistics of TVD, PVD, and MFI to determine normal ranges for both manual and automated analysis methods at the population level as well as age-related subgroup level (18-34 yrs, 35-54 yrs and 55 yrs and over). (b.) Estimation of correlation between automatically and manually derived values of TVD, PVD, and MFI within each subject. (c.) Comparison of mean TVD, PVD, and MFI between the age-related subgroup (18-34yrs, 35-54 yrs and 55 yrs and over). Progress: This study has currently recruited 91 of 150 subjects. The procedure of measurement has been found to be well tolerated, with no subjects withdrawing from the study once enrolled. Further, it has been possible, following 2 days of intense work, to train a further member of the team to make reliable, high quality recordings, demonstrating the scope for training those new to the technique to use it in the clinical setting. We look forward to producing full results in the near future.

Nitrite circumvents platelet resistance to nitric oxide in patients with heart failure preserved ejection fraction and chronic atrial fibrillation.

AimsHeart failure (HF) is a pro-thrombotic state. Both platelet and vascular responses to nitric oxide (NO) donors are impaired in HF patients with reduced ejection fraction (HFrEF) compared with healthy volunteers (HVs) due to scavenging of NO, and possibly also reduced activity of the principal NO sensor, soluble guanylate cyclase (sGC), limiting the therapeutic potential of NO donors as anti-aggregatory agents. Previous studies have shown that nitrite inhibits platelet activation presumptively after its reduction to NO, but the mechanism(s) involved remain poorly characterized. Our aim was to compare the effects of nitrite on platelet function in HV vs. HF patients with preserved ejection fraction (HFpEF) and chronic atrial fibrillation (HFpEF–AF), vs. patients with chronic AF without HF, and to assess whether these effects occur independent of the interaction with other formed elements of blood.Methods and resultsPlatelet responses to nitrite and the NO donor sodium nitroprusside (SNP) were compared in age-matched HV controls (n = 12), HFpEF–AF patients (n = 29), and chronic AF patients (n = 8). Anti-aggregatory effects of nitrite in the presence of NO scavengers/sGC inhibitor were determined and vasodilator-stimulated phosphoprotein (VASP) phosphorylation was assessed using western blotting. In HV and chronic AF, both nitrite and SNP inhibited platelet aggregation in a concentration-dependent manner. Inhibition of platelet aggregation by the NO donor SNP was impaired in HFpEF-AF patients compared with healthy and chronic AF individuals, but there was no impairment of the anti-aggregatory effects of nitrite. Nitrite circumvented platelet NO resistance independently of other blood cells by directly activating sGC and phosphorylating VASP.ConclusionWe here show for the first time that HFpEF-AF (but not chronic AF without HF) is associated with marked impairment of platelet NO responses due to sGC dysfunction and nitrite circumvents the ‘platelet NO resistance’ phenomenon in human HFpEF, at least partly, by acting as a direct sGC activator independent of NO.

S43. A PROOF-OF-MECHANISM STUDY OF THE PDE10 INHIBITOR RG7203 IN PATIENTS WITH PROBING REWARD FUNCTIONS WITH IMAGING AND BEHAVIORAL APPROACHES

BackgroundThe enzyme phosphodiesterase 10A (PDE10A) is highly expressed in the striatum where it modulates both dopamine D2 and D1 dependent signaling. Its inhibition leads to a suppression of D2 mediated signaling –similar to effects of D2 antagonists - and an enhancement of D1 dependent signaling. D1-dependent signaling has been implicated in reward based learning. Its deficient activation may be a key factor underlying deficient reward functions including reward anticipation and reward based learning that have been implicated as major drivers of negative symptoms of schizophrenia. Therefore, inhibition of PDE10 could be a way to ameliorate such deficits and consequently negative symptoms. In healthy volunteers the PDE10 inhibitor RG7203 indeed enhanced performance in tasks that probed reward functioning suggestive of its potential utility to treat negative symptoms in schizophrenia. We therefore tested the hypothesis that it should enhance imaging and behavioral markers of reward functions in patients with moderate negative symptoms in order to establish mechanistic proof of its utility as treatment of negative symptoms.MethodsIn a three-way cross-over study we investigated the effects of two doses of RG7203 (5 mg and 15 mg) and placebo given as adjunctive treatment to stable background antipsychotic treatment on reward functioning and reward-based effortful behavior using the monetary incentive delay (MID) task during fMRI and the effort choice task in patients with chronic schizophrenia and moderate levels of negative symptoms (PANSS negative symptom factor score ≥ 18 points). Each treatment period lasted three weeks followed by a 2 week washout period. fMRI and behavioral tasks were administered at the end of each treatment period. Key outcome measures were the differential BOLD during reward anticipation and overall BOLD activity during the MID task and the percentage of high-effort high-reward choices when the probability of reward was 100% during the effort choice task.ResultsThirty-three patients with schizophrenia (30 male; 21 B, 9 W, 3 A; mean age 36.6 ± 7 y; PANSS NSFS = 22.8 (±1.4) at screening) were recruited at three study centers in the US. Twenty-four subjects finished the entire study. RG7203 at 5 mg significantly increased differential BOLD activity during reward anticipation in the MID task. However, this enhancement occurred in the context of a significant decrease of BOLD activity across all conditions during the MID task under treatment with RG7203. RG7203 significantly worsened reward-based effortful behavior in the effort choice task (the high-effort high-reward choice: 67% for both doses of RG7203 versus 73% for placebo). Multiple regression revealed that the decrease in effortful behavior was significantly related to the decrease in overall BOLD activity during the MID task and not related to the difference of BOLD activity during reward anticipation versus the control condition.DiscussionIn contrast to our expectation and previous results in healthy volunteers, RG7203 worsened indices of reward functions which we hypothesize may be due to a further enhancement of D2 antagonistic activity. The results do not support the utility of a PDE10 inhibitor as adjunctive treatment for negative symptoms in patients with schizophrenia. Given the previous observation that RG7203 enhanced reward functions in healthy volunteers who were not treated with D2 antagonist, the results of our study point to potentially deleterious effects of D2 blockade on reward functions and by extension on negative symptoms of schizophrenia. They raise the question if the presence of D2 antagonistic treatment curtails the potential effects of any adjunctive treatment for negative symptoms.

Influence of long-term treatment with glyceryl trinitrate on remote ischemic conditioning.

Remote ischemic conditioning (RIC) protects against sustained myocardial ischemia. Because of overlapping mechanisms, this protection may be altered by glyceryl trinitrate (GTN), which is commonly used in the treatment of patients with chronic ischemic heart disease. We investigated whether long-term GTN treatment modifies the protection by RIC in the rat myocardium and human endothelium. We studied infarct size (IS) in rat hearts subjected to global ischemia-reperfusion (I/R) in vitro and endothelial function in healthy volunteers subjected to I/R of the upper arm. In addition to allocated treatment, rats were coadministered with reactive oxygen species (ROS) or nitric oxide (NO) scavengers. Rats and humans were randomized to 1) control, 2) RIC, 3) GTN, and 4) GTN + RIC. In protocols 3 and 4, rats and humans underwent long-term GTN treatment for 7 consecutive days, applied subcutaneously or 2 h daily transdermally. In rats, RIC and long-term GTN treatment reduced mean IS (18 ± 12%, P = 0.007 and 15 ± 5%, P = 0.002) compared with control (35 ± 13%). RIC and long-term GTN treatment in combination did not reduce IS (29 ± 12%, P = 0.55 vs. control). ROS and NO scavengers both attenuated IS reduction by RIC and long-term GTN treatment. In humans, I/R reduced endothelial function ( P = 0.01 vs. baseline). Separately, RIC and long-term GTN prevented the reduction in endothelial function caused by I/R; given in combination, prevention was lost. RIC and long-term GTN treatment both protect against rat myocardial and human endothelial I/R injury through ROS and NO-dependent mechanisms. However, when given in combination, RIC and long-term GTN treatment fail to confer protection. NEW & NOTEWORTHY Remote ischemic conditioning (RIC) and long-term glyceryl trinitrate (GTN) treatment protect against ischemia-reperfusion injury in both human endothelium and rat myocardium. However, combined application of RIC and long-term GTN treatment abolishes the individual protective effects of RIC and GTN treatment on ischemia-reperfusion injury, suggesting an interaction of clinical importance.

Axiographic Assessment of Masticatory System function in Healthy Volunteers

Background: The use of axiographic devices provides a simple and minimally invasive way to detect masticatory abnormalities, enabling early preventive action and treatment with a long-term impact on the good functioning of the masticatory systemObjective: The aim of the study was to collect normative data from the stomatognathicsystem using elecrtonic axiography and to find the differences between males and females.Material: The study evaluated 98 females and 88 males, in a mean age of 19 years with full natural dentition corresponding to Angle’s Class I.Methods: All the participants undertook clinical examination and electronic axiography using the Cadiax Compact II.Results: A significantly higher Quantity Maximal S3d in men (p=0.021), a trend towards higher Transverse Condyle Inclination Values 3 mm in women and a significantly lower reproducibility of the opening and closing movements were found in women (p=0.022).Conclusion: The graphs of opening and closing movements in a group of healthy women and men with no symptoms from the masticatory system differed significantly between genders. The Quantity Maximal S3d parameter is higher in men, but because of the large range of values, this parameter cannot be a single criterion used to detect TMJ dysfunction.

Immediate effect of hot chest pack on cardio-respiratory functions in healthy volunteers: A randomized cross-over study

BackgroundThe chest pack is one of the most common hydrotherapy procedures. Though the hot chest pack (HCP) is commonly employed by many practitioner to improve various cardio-respiratory problems, there is no scientific report validating its effect on either cardiovascular or respiratory functions. The current study has been conducted to evaluate the effect of cardio-respiratory functions in healthy volunteers. Materials and methodsThirty healthy female volunteers with the age range of 18–24 years were recruited and randomly divided into 2-groups. Subjects of both the groups underwent 20-min each of HCP (study session) and supine rest (SR - control session) sessions in 2-different orders. In the first group, 15 subjects underwent HCP on day-1 and SR on day-2, while in the second group the order of intervention was reversed. Assessments were taken before and after each session. Statistical analysis was performed using statistical package for the social sciences, version 16. ResultsA significant reduction in systolic blood pressure was observed both in study and control sessions. However, a significant reduction in diastolic blood pressure, mean arterial pressure, pulse rate, rate pressure product (RPP) and double product (Do-P), along with a significant improvement in peak expiratory flow rate, was observed only in the HCP session. Reduction in RPP and Do-P was better in the HCP session than in the control session. ConclusionResults of this study suggest that 20min of HCP might be effective in improving cardio-respiratory functions of healthy volunteers.

Effect of High Inspiratory Oxygen Fraction on Endothelial Function in Healthy Volunteers: A Randomized Controlled Crossover Pilot Study.

It has been suggested that high inspiratory oxygen concentrations during anesthesia may be associated with higher postoperative mortality due to endothelial dysfunction. A randomized controlled crossover study was conducted with 25 healthy male volunteers. They inhaled an oxygen concentration of 30% and 80%. The endothelial function was assessed using noninvasive digital pulse amplitude tonometry (EndoPAT) supported by endothelial biomarkers. The difference in endothelial function between the 2 treatments was 0.05 (95% confidence interval, -0.36 to 0.27; P = .77). Endothelial biomarkers were unaffected. Inhalation of a high oxygen fraction in healthy volunteers did not result in a significant reduction of endothelial function.

The effect of mirtazapine on gastric accommodation, gastric sensitivity to distention, and nutrient tolerance in healthy subjects.

Disturbances of gastric motor function of functional dyspepsia (FD) have been implicated in the pathogenesis of the symptoms, and hence, motility modifying agents are considered for its treatment. Mirtazapine was recently shown to improve symptoms and increase nutrient tolerance in FD patients with weight loss. We aim to evaluate the effect of mirtazapine on gastric sensorimotor function in healthy volunteers (HV). Thirty-one HV underwent an intragastric pressure (IGP) and barostat measurements on separate days before and after 3weeks of placebo or mirtazapine (15mg). Gastric compliance, sensitivity and accommodation (GA) measured by the barostat. GA was quantitated as the difference (delta) in intra-balloon volume before and after ingestion of 200mL of a nutrient drink (ND). GA measured by IGP was quantitated as the drop of IGP from baseline during the intragastric infusion of ND until maximal satiation. Mirtazapine significantly increased the bodyweight of subjects (67.8±3.7 to 69.1±3.7kg; P=.01). Barostat results showed no effect on gastric compliance, sensitivity, and GA. Nutrient tolerance was not affected after treatment (1170±129.4 vs 1104±133.6kcal; P=.4), and mirtazapine was associated with lower symptom ratings. The IGP drop during meal ingestion was significantly suppressed (area under the curve: -43.3±4.5mm Hg vs -28.9±3.1mm Hg; P=.005). In HVs, the occurrence of weight gain and decreased meal-induced symptoms in spite of a suppressed meal-induced IGP drop, point towards a central mode of action. Mirtazapine does not display changes in gastric sensorimotor function that could explain its beneficial effects on symptoms and nutrient tolerance in FD.