Stress In Healthy Volunteers Research Articles

Efficacy of Vasantik Vaman Karma (Therapeutic Emesis) on Oxidative Stress Markers in Healthy VolunteersA Pilot Randomised Controlled Study

Introduction: Vamana karma is a therapeutic emesis procedure recommended for maintaining health in healthy individuals. It is said to be conducted during the Vasant rutu (spring season) and is referred to as Vasantik Vaman. During this season, there is an aggravation of Kapha dosha, which can lead to various diseases. The bio-purification of the body in Vasant rutu through the Vaman procedure helps to detoxify and rejuvenate the body. To make this practice evidence-based, the present study was planned to evaluate the efficacy of Vamana karma, which is also considered a shodhana karma, in reducing oxidative stress. Aim: To compare the efficacy of Vasantik Vamana karma on Malondialdehyde (MDA) and Superoxide Dismutase (SOD) levels as markers of oxidative stress in healthy volunteers, compared to a non interventional group. Materials and Methods: The present randomised controlled study was conducted in the Department of Kriyasharir, Mahatma Gandhi Ayurved College, Hospital and Research Centre, under the auspices of Datta Meghe Institute of Higher Education University, Wardha, Maharashtra, India, from March 2023 to April 2023 during the Vasant rutu. A total of 58 healthy individuals aged between 20 years and 40 years were sensitised regarding the procedure and benefits of Vasantik Vamana karma. After sensitisation, 30 volunteers who provided written consent for participation in the study were enrolled, examined and randomly divided into two groups: Group A (non interventional) and Group B (interventional). Both groups were assessed on the 0th day and the 15th day for oxidative stress markers, specifically free radicals (MDA) and antioxidant (SOD) levels. Statistical analysis was done using descriptive and inferential statistics, including Student’s paired and unpaired t-tests. Results: The mean±Standard Deviation (SD) age of participants was 21.23±0.37 years, with participation almost equal from both genders. Before the intervention, SOD and MDA levels were similar in both the control and interventional groups. After the intervention of Vasantik Vamana karma, Group B showed an increase in SOD levels and a decrease in MDA levels, which were statistically highly significant according to the paired t-test (p-value≤0.001) in comparison to the non interventional group. In the non interventional group, p-value=0.951 for SOD levels and 0.551 for MDA levels by paired t-test, which were not significant. When both groups were compared using an unpaired test, at pre-intervention, both groups were at the same level, but after the intervention, statistically significant results were observed in Group B (p-value≤0.001). Conclusion: The present study concluded that Vasantik Vamana karma, as a bio-purification process, Vasantik Vamana karma has proven to be highly effective in detoxifying the body by reducing oxidative stress in healthy volunteers.

Contributors to beat-to-beat stroke volume variability during acute mental stress in healthy volunteers.

Acute mental stress elicits sympathetic activation, increasing heart rate and shortening the QT interval, but it is unknown whether this activation translates to stroke volume (SV) changes. Multivariate power spectral decomposition was used to assess the influence of heart rate and QT variabilities on SV variability at rest and during acute mental stress. Acute mental stress elicits mild but statistically significant increase in SV variability. Heart rate variability contributes almost one third of SV variability, while the contribution of QT variability is below 3%. In conclusion, although heart rate variability appears to contribute directly to increase in SV variability during acute mental stress, most of SV variability is attributed to sources independent of heart rate and QT variabilities.Clinical Relevance-Acute mental stress elicits small fluctuations in stroke volume in healthy volunteers. Its significance for clinical populations remains to be established.

Effects of Turmeric Concentrate on Cardiovascular Risk Factors and Exercise-Induced Oxidative Stress in Healthy Volunteers; an Exploratory Study.

Evidence suggests that turmeric intake can improve antioxidant defense, blood pressure (BP), ageing and gut microbiota. The effects of turmeric concentrate (curcumin) intake on cardiovascular risk factors and exercise induced oxidative stress were investigated. A randomized placebo-controlled study was performed to assess the effects of turmeric extract in healthy volunteers before and after a 30 min exercise bout. Participants (n=22) were given either turmeric concentrate or placebo supplements. Anthropometry, BP, pulse wave velocity (PWV), biomarkers of oxidative stress, perceived exertion and lipid peroxidation were assessed. In the turmeric group, the expected BP response to exercise following turmeric was blunted and the increase was not significant compared to basal values followed by a decrease in final BP and PWV values. There were no significant differences in all baseline parameters between the placebo and the curcumin groups (P>0.05). A significant increase was observed in urinary antioxidant power (P=0.031) and total polyphenol levels (P=0.022) post turmeric intervention. The distance ran by the participants taking turmeric was significantly longer (P=0.005) compared to basal value. Those who took the placebo did not show significant changes. Our study suggests that turmeric concentrate intake can reduce BP and improve antioxidant, anti-inflammatory status and arterial compliance. Turmeric may improve exercise performance and ameliorates oxidative stress. Larger studies are warranted to validate these findings and test more cardiovascular risk factors.

Compact MR-compatible ergometer and its application in cardiac MR under exercise stress: A preliminary study.

PurposeTo develop a compact MR‐compatible ergometer for exercise stress and to initially evaluate the reproducibility of myocardial native T1 and myocardial blood flow (MBF) measurements during exercise stress performed on this ergometer.MethodsThe compact ergometer consists of exercise, workload, and data processing components. The exercise stress can be achieved by pedaling on a pair of cylinders at a predefined frequency with adjustable resistances. Ten healthy subjects were recruited to perform cardiac MRI scans twice in a 3.0T MR scanner, at different days to assess reproducibility. Myocardial native T1 and MBF were acquired at rest and during a moderate exercise. The reproducibility of the two tests was determined by the intra‐group correlation coefficient (ICC) and coefficient of variation (CoV).ResultsThe mean exercise intensity in this pilot study was 45 Watts (W), with an exercise duration of 5 min. Stress induced a significant increase in systolic blood pressure (from 113 ± 11 mmHg to 141 ± 12, P < 0.05) and maximal increase in heart rate by 74 ± 19%. The rate pressure product increased two‐fold (P < 0.001). Excellent reproducibility was demonstrated in native T1 during the exercise (CoV = 3.0%), whereas the reproducibility of MBF and myocardial perfusion reserve during the exercise was also good (CoV = 10.7% and 8.8%, respectively).ConclusionThis pilot study demonstrated that it is possible to acquire reproducible measurements of myocardial native T1 and MBF during the exercise stress in healthy volunteers using our new compact ergometer.

P310. Effect of a Sub-Anesthetic Infusion of Ketamine on Laboratory-Induced Stress in Healthy Volunteers: A Proof-Of-Concept Translational Study

Stress exposure is a key risk factor for the development of major depressive disorder and posttraumatic stress disorder. Enhancing stress resilience in at-risk populations could potentially protect against stress-induced disorders. The administration of ketamine one week prior to an acute stressor prevents the development of stress-induced depressive-like behavior in rodents. This study aimed to test if the stress prophylactic effect of ketamine applies also to humans.

Regulation of free radical processes in healthy volunteers during experimental hyperthermia and in patients with coronary artery disease during summer heat waves

Background. In view of the worsening forecast for global temperature rise worldwide, it seems relevant to study the effects of abnormal heat waves on systemic regulatory processes in people with chronic diseases, in particular coronary artery disease (CAD).Aims. This study aimed to investigate the effect of hyperthermia on oxidative stress parameters in patients with various severity of CAD and in healthy subjects.Materials and methods. We studied the level of malonic dialdehyde (MDA) and the activity of Cu,Zn-containing superoxide dismutase (Cu,Zn-SOD) in healthy subjects under conditions of 30-day long simulated hyperthermia and in patients with different severity of CAD after the summer heat wavesResults. We revealed signs of oxidative stress in healthy volunteers during model hyperthermia that manifested as an increase in content of MDA in blood plasma. At the same time we observed increasing activity of Cu,Zn-SOD in erythrocytes that utilizes reactive oxygen species. The increase of Cu,Zn-SOD activity started with a certain latency what also can be explained by de novo enzyme biosynthesis induction. We also studied oxidative stress parameters in patients at high and moderate cardiovascular risk according to the SCORE risk chart with uncomplicated CAD course and in patients with complicated CAD with severe coronary damage according to angiography during the summer heat waves. We observed accumulation of MDA in blood plasma and increasing activity of erythrocyte Cu,Zn-SOD in patients with uncomplicated CAD. At the same time we noted that accumulation of MDA in blood plasma was not followed by any increase in activity of red blood cell Cu,Zn-SOD in patients with severe complicated CAD. This fact indicates dysregulation of free radical processes in patients with severe course of CAD during the heat waves.Conclusions. The dysregulation of free-radical processes in patients with a severe clinical course of CAD has been revealed.

Abstract 10484: Cardiac Adaptation to Acute Haemodynamic Stress in Patients with Type 2 Diabetes

Background: Due to varying cardiac workloads, efficient demand-supply matching is crucial for maintaining normal cardiac function. Cardiac metabolism is profoundly affected by changes in cardiac workload. There is scarcity of non-invasive studies evaluating how the heart adapts to hemodynamic stress in type 2 diabetes (T2D) patients. Objectives: Using cardiovascular magnetic resonance (CMR) and 31 Phosphorus MR spectroscopy ( 31 P-MRS) we assessed changes in cardiac energetics, perfusion, strain, systolic and diastolic function in response to increases in cardiac workload with dobutamine stress in T2D patients and healthy volunteers (HV). Methods: 24 T2D patients and 18 matched HV were recruited. Participants with ischemic heart disease were excluded. Results: Table-1 shows clinical and CMR/ 31 P-MRS data. Compared to HV, T2D patients showed reductions in left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) at rest, and a blunted increase in LVEF and GLS during stress. Diastolic function was impaired in T2D with lower mitral in-flow E/A ratio compared to HV at rest, which was further reduced during stress in both groups. Stress myocardial blood flow was lower in T2D patients.Compared to HV, rest phosphocreatinine (PCr)/ATP ratio was 17% lower in T2D patients, with a further 8% reduction during stress. However, there was a more pronounced reduction in the PCr/ATP with stress in HV (33% relative reduction), although stress PCr/ATP remained numerically higher in HV compared to T2D patients. Conclusions: T2D is associated with blunted ability of the myocardium to significantly increase contractile function from rest to stress. Moreover, T2D patients show exacerbated reductions in myocardial energetics and diastolic function during stress. Although reductions in myocardial energetics and diastolic function in response to acute stress were also detected in HV, these assessments remained higher in HV at stress compared to T2D patients.

Pulse Arrival Time - A Sensitive Vital Parameter for the Detection of Mental Stress

Abstract Mental stress triggers positive inotropic and chronotropic effects as well as peripheral vasoconstriction. This alters the pulse arrival time (PAT), the duration between electrical excitation of the ventricles and arrival of the pulse wave in the periphery. We conducted a study to examine PAT during five rest blocks and under mental stress utilizing the Mannheim Multicomponent Stress Test. Electrocardiograms as well as finger and earlobe photoplethysmograms were recorded. PAT was calculated for over 135,000 heartbeats from 42 healthy volunteers as the time duration between the R peak in the electrocardiogram and the following pulse onset in the respective photoplethysmogram. To identify the effect of mental stress, block-wise PAT means were statistically analyzed with repeated measures ANOVA. The analyses showed significant differences between the block means for both PAT measures (p &lt; 0.001). Post-hoc tests revealed significantly reduced PAT during the stress block compared to all rest blocks for both PAT measures (p &lt; 0.001). We found no significant differences between the rest blocks. Our results support that PAT is a sensitive vital parameter for the detection of mental stress in healthy volunteers. This holds true for both measurement positions, the finger and the earlobe.

Atypical opioids and their effect on respiratory drive.

Opioids are an important tool in the treatment of pain, but opioid overdose has become a serious health issue. Most opioid-related deaths are caused by respiratory depression, and the risk of respiratory depression is compounded because of the risks of abuse and diversion, which makes the need for safer opioids even more urgent. However, the atypical opioids (buprenorphine, tramadol, and tapentadol), with mechanisms of action not purely driven by µ-opioid receptor agonism, may be safer than conventional opioids, eg, morphine, oxycodone, and fentanyl. The purpose of this narrative review is to describe the clinical and experimental evidence regarding opioid-induced respiratory depression in the context of the mechanisms of action of the atypical opioids. Among the atypical opioids, tramadol has an advantage of being a Schedule IV drug, and thus having a relatively low abuse potential-but its effects, including its effect on respiratory drive, are dependent on cytochrome P450 2D6 metabolizer status. Tapentadol appears to affect respiratory drive, but this has not been well investigated. Buprenorphine is a Schedule III drug, thus having less abuse potential than the majority of opioids. Experimentally, a ceiling effect on the respiratory depression has been reported with intravenous buprenorphine. In addition, experimental hypercapnic stress in healthy volunteers demonstrated no respiratory depression following the administration of a single dose of the buccal film formulation of buprenorphine when compared with placebo. Overall, the data suggest that atypical opioids may be a safer option than conventional opioids for the treatment of pain.

A combination of green tea, rhodiola, magnesium and B vitamins modulates brain activity and protects against the effects of induced social stress in healthy volunteers

ABSTRACT Background Magnesium (Mg), green tea and rhodiola extracts have, in isolation, been shown to possess stress and anxiety relieving effects. Green tea and rhodiola have been shown to modulate EEG oscillatory brain activity associated with relaxation and stress perception. The combined capacity of these ingredients to confer protective effects under conditions of acute stress has yet to be examined. We tested the hypothesis that a combination of Mg (with B vitamins) + green tea + rhodiola would acutely moderate the effects of stress exposure. Methods A double blind, randomised, placebo controlled, parallel group design was employed (Clinicaltrials.gov:NCT03262376; 25/0817). One hundred moderately stressed adults received oral supplementation of either (i) Mg + B vitamins + green tea + rhodiola; (ii) Mg + B vitamins + rhodiola; (iii) Mg + B vitamins + green tea; or (iv) placebo. After supplementation participants were exposed to the Trier Social Stress Test. The effects of the study treatments on electroencephalogram (EEG) resting state alpha and theta, subjective state/mood, blood pressure, heart rate variability and salivary cortisol responses after acute stress exposure were assessed. Results The combined treatment significantly increased EEG resting state theta (p < .02) – considered indicative of a relaxed, alert state, attenuated subjective stress, anxiety and mood disturbance, and heightened subjective and autonomic arousal (p < .05). Conclusions Mg, B vitamins, rhodiola and green tea extracts are a promising combination of ingredients that may enhance coping capacity and offer protection from the negative effects of stress exposure. Trial registration: ClinicalTrials.gov identifier: NCT03262376.

Acute physical and mental stress resulted in an increase in fatty acids, norepinephrine, and hemodynamic changes in normal individuals: A possible pathophysiological mechanism for hypertension—Pilot study

Hypertension is often associated with metabolic changes. The sustained increase in sympathetic activity is related to increased blood pressure and metabolic changes. Environmental stimuli may be related to increased sympathetic activity, blood pressure, and metabolic changes, especially in genetically predisposed individuals. The aim of this study was to evaluate the response of fatty acids to physical and mental stress in healthy volunteers and the hemodynamic, hormonal, and metabolic implications of these stimuli. Fifteen healthy individuals with a mean age of 31 ± 7 years, of both sexes, were evaluated. They were assessed at baseline and after combined physical and mental stress (isometric exercise test, Stroop color test). Blood samples were collected at baseline and after stimulation for glucose, insulin, fatty acid, and catecholamine levels. Blood pressure, heart rate, cardiac output, systemic vascular resistance, and distensibility of the large and small arteries were analyzed. The data obtained at baseline and after stimuli were from the same individual, being the control itself. Compared to baseline, after physical and mental stress there was a statistically significant increase (p < .05) in free fatty acids, norepinephrine, diastolic blood pressure, peripheral vascular resistance, and distensibility of the large and small arteries. In conclusion, the combination of physical and mental stress raised fatty acids, norepinephrine, diastolic blood pressure, and peripheral vascular resistance in healthy individuals.

Repeatability of Neural and Autonomic Responses to Acute Psychosocial Stress.

FMRI Montreal Imaging Stress Tasks (MIST) have been shown to activate endocrine and autonomic stress responses that are mediated by a prefrontal cortex (PFC)-hippocampus-amygdala circuit. However, the stability of the neurobehavioral responses over time and the ability to monitor response to clinical interventions has yet to be validated. The objective of this study was to compare the fMRI and physiologic responses to acute psychosocial stress in healthy volunteers during initial and follow-up visits approximately 13 weeks later, simulating a typical duration of clinical intervention. We hypothesized that responses to stress would remain highly conserved across the 2 visits in the absence of an intervention. 15 healthy volunteers completed a variant of control math task (CMT) and stress math task (SMT) conditions based on MIST. Neural responses were modeled using an event-related design with estimates for math performance and auditory feedback for each task condition. For each visit, measures of stress reactivity included differential fMRI and heart rate (SMT-CMT), as well as salivary alpha-amylase before and after scanning sessions. The results revealed that differential fMRI, as well as increased heart rate and salivary alpha-amylase from before and after scanning remained similar between visits. Intraclass correlation coefficient (ICC) values revealed areas of reliable task-dependent BOLD fMRI signal response across visits for peaks of clusters for the main effect of condition (SMT vs CMT) within dorsal anterior cingulate cortex (ACC), insula, and hippocampus regions during math performance and within subgenual ACC, posterior cingulate cortex, dorsolateral PFC regions during auditory feedback. Given that the neurobehavioral response to acute stress remained highly conserved across visits in the absence of an intervention, this study confirms the utility for MIST for assessing longitudinal changes in controlled trials that can identify underlying neurobiological mechanisms involved in mediating the efficacy of stress-reduction interventions.

Efficacy of probiotics on stress in healthy volunteers: A systematic review and meta-analysis based on randomized controlled trials.

BackgroundProbiotics seems to play a beneficial role in stressed populations; thus, a systematic review and meta‐analysis to assess the effects of probiotics on stress in healthy subjects were conducted.MethodsRandomized controlled trials on the effects of probiotics on stress in healthy subjects were retrieved from five databases. The effects of probiotics on subjective stress level, stress‐related subthreshold anxiety/depression level, cortisol level, and adverse reactions were analyzed. Separate subgroup analyses were conducted on single‐strain probiotics versus multi‐strain probiotics, and short‐term administration versus long‐term administration.ResultsSeven studies were included, involving a total of 1,146 subjects. All the studies were rated as low or moderate risk of bias. Our research found that probiotic administration can generally reduce the subjective stress level of healthy volunteers and may improve their stress‐related subthreshold anxiety/depression level, but no significant effect was observed in the subgroup analysis. The effect of probiotics on cortisol level was not significant. Adverse reactions were reported in only one of seven studies, but left undescribed.ConclusionCurrent evidence suggests that probiotics can reduce subjective stress level in healthy volunteers and may alleviate stress‐related subthreshold anxiety/depression level, without significant effect on cortisol level, and there is not enough support to draw conclusions about adverse effects; thus, more reliable evidence from clinical trials is needed.

Brainstem Correlates of a Cold Pressor Test Measured by Ultra-High Field fMRI.

IntroductionModern imaging techniques such as blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) allow the non-invasive and indirect measurement of brain activity. Whether changes in signal intensity can be detected in small brainstem regions during a cold pressor test (CPT) has not been explored thoroughly. The aim of this study was to measure whole brain and brainstem BOLD signal intensity changes in response to a modified CPT.MethodsBOLD fMRI was measured in healthy normotensive participants during a randomized crossover study (modified CPT vs. control test) using ultra-high field 7 Tesla MRI scanner. Data were analyzed using Statistical Parametric Mapping (SPM) in a whole-brain approach, and with a brainstem-specific analysis using the spatially unbiased infra-tentorial template (SUIT) toolbox. Blood pressure (BP) and hormonal responses (norepinephrine and epinephrine levels) were also measured. Paired t-test statistics were used to compare conditions.ResultsEleven participants (six women, mean age 28 ± 8.9 years) were analyzed. Mean arterial BP increased from 83 ± 12 mm Hg to 87 ± 12 mm Hg (p = 0.0009) during the CPT. Whole-brain analysis revealed significant activations linked to the CPT in the right supplementary motor cortex, midcingulate (bilateral) and the right anterior insular cortex. The brainstem-specific analysis showed significant activations in the dorsal medulla.ConclusionChanges in BOLD fMRI signal intensity in brainstem regions during a CPT can be detected, and show an increased response during a cold stress in healthy volunteers. Consequently, BOLD fMRI at 7T is a promising tool to explore and acquire new insights in the comprehension of neurogenic hypertension.

The Effect of Stress on Repeated Painful Stimuli with and Without Painful Conditioning.

Stress and pain have been interrelated in clinical widespread pain conditions. Studies indicate that acute experimental stress in healthy volunteers has a negative effect on the descending inhibitory pain control system and thus the ability to inhibit one painful stimulus with another (conditioned pain modulation [CPM]) although without effect on general pain sensitivity. CPM effects can be assessed immediately after the stress induction, whereas some physiological stress responses (e.g., cortisol release) are delayed and longer lasting. It is unclear whether CPM may relate to stress-induced increases in cortisol. Twenty-five healthy men had CPM effects measured over a period of 10 minutes. Pain detection thresholds (PDTs) were assessed by repeated test stimuli with cuff algometry on one leg, with and without painful cuff pressure conditioning on the contralateral leg. CPM effects, assessed as the increase in PDT during conditioning stimulation compared with without, were measured before and after experimental stress and a control condition (Montreal Imaging Stress Task [MIST]). Saliva cortisol levels and self-perceived stress were collected. Participants reported the MIST to be more stressful compared with the MIST control, but cortisol levels did not change significantly from baseline. In all sessions, PDT increased during conditioning (P = 0.001), although the MIST compared with the MIST control had no significant effect on PDT or CPM effects. A negative correlation between changes in cortisol and conditioned PDT was found when applying the MIST (P < 0.03). No significant effect of stress was found on CPM compared with a matched control condition. Individual changes in experimental stress and in conditioned pain sensitivity may be linked with cortisol.

Acupuncture and Acupressure Applied on the Extra-1 (Yintang) Acupoint in Healthy Volunteers Do Not Affect Regional Cerebral Blood Flow as Assessed by the Pulsatility Index: A Cohort Observational Study.

Objective: Acupressure applied on the Extra-1 (Yintang) point decreases bispectral index (BIS) values and stress in healthy volunteers. The current authors hypothesized that acupressure and/or acupuncture could alter regional cerebral oxygenation as expressed by middle cerebral-artery velocity. This study was conducted to test that hypothesis. Materials and Methods: After giving written informed consent, healthy volunteers received, randomly, (1) acupressure on the Extra-1 (Yintang) point, (2) acupressure on a sham point lying 2 cm over the lateral end of the right eyebrow, (3) no acupressure, or (4) modified manual acupuncture on the Extra-1 (Yintang) point. Each intervention lasted 10 minutes, except for acupuncture, which lasted for 20 minutes. The flow velocity of the left middle cerebral artery-as expressed by the Pulsatility Index (PI), heart rate (HR), and hemoglobin oxygen saturation (SpO2)-was recorded before each intervention, every 2 minutes during the intervention, and 10 and 70 minutes after the end of the intervention. A 2-MHz hand-held probe of a transcranial Doppler system (Companion II Micro TCD Nikolet Biomedical Inc., Madison, WI) was used to isolate the left middle cerebral artery via a transtemporal approach. Results: There was no difference among the four interventions at any timepoint in PI (P = 0.431; F = 0.929), HR (P = 0.948; F = 0.121), and SpO2 (P = 0.708; F = 0.465), as well as in systolic arterial pressure (P = 0.857; F = 0.255) or diastolic arterial pressure (P = 0.991; F = 0.036). Conclusions: There were no changes in PI measurements when acupuncture or acupressure was applied on the Extra-1 (Yintang) point once and for a limited time duration.

Rapid on-site dual optical system to measure specific reactive oxygen species (O2-• and OCl-) in a tiny droplet of whole blood.

Oxidative stress has been implicated in various disorders and controlling it would be important for healthy life. We have developed a new optical system for easily and accurately measuring oxidative stress in whole blood. It is optimized for simultaneously detecting reactive oxygen species (ROS) and highly reactive ROS (hROS), elicited mostly by white blood cells in a few microliters of blood. Results obtained by using this system show at least four important findings. 1) chemiluminescence of MCLA was confirmed to be attributable to O2-•. 2) PMA-stimulated cells released O2-• longer and more slowly than fMLP-stimulated ones. 3) fluorescence produced by APF oxidation was confirmed to be attributable to hROS, mostly OCl-, produced by myeloperoxidase. 4) the generation of OCl- was found to be a slower process than the O2-• generation. We also conducted pilot studies of oxidative stress in healthy volunteers.

Quantification of aortic stiffness and wall stress in healthy volunteers and abdominal aortic aneurysm patients using time-resolved 3D ultrasound: a comparison study

Using non-invasive 3D ultrasound, peak wall stress (PWS) and aortic stiffness can be evaluated, which may provide additional criteria in abdominal aortic aneurysm (AAA) risk assessment. In this study, these measures were determined in both young and age-matched individuals, and AAA patients while its relation to age, maximum diameter, and growth was assessed statistically. Time-resolved 3D-US data were acquired for 30 volunteers and 65 AAA patients. The aortic geometry was segmented, and tracked over the cardiac cycle using 3D speckle tracking to characterize the wall motion. Wall stress analysis was performed using finite element analysis. Model parameters were optimized until the model output matched the measured 3D displacements. A significant increase in aortic stiffness was measured between the age-matched volunteers [median 0.58, interquartile range (IQR) 0.48-0.71 kPa⋅m] and the small AAA patients (median 1.84, IQR 1.38-2.46 kPa⋅m; P < 0.001). In addition, an increase in aortic stiffness was evaluated between the small (30-39 mm) and large (≥50 mm) AAAs (median 2.72, IQR 1.99-3.14 kPa⋅m; P = 0.01). The 99th percentile wall stress showed a positive correlation with diameter (ρ = 0.73, P < 0.001), and significant differences between age-matched volunteers and AAA patients. The AAA pathology causes an early and significant increase in aortic stiffness of the abdominal aorta, even after correcting for the expected effect of ageing and differences in arterial pressure. Moreover, some AAAs revealed relatively high PWS, although the maximum diameter was below the threshold for surgical repair. Using the current method, these measures become available during follow-up, which could improve AAA rupture risk assessment.

Quantitative analysis of scapholunate diastasis using stress speckle-tracking sonography: a proof-of-concept and feasibility study.

To evaluate the feasibility and potential clinical applicability of speckle-tracking sonography for the dynamic evaluation of the scapholunate diastasis during stress manoeuvres. Two readers used speckle tracking sonography to evaluate scapholunate diastasis during a clenching fist manoeuver in 30 normal wrists. Scapholunate peak strain, mean scapholunate diastasis and the diastasis variation coefficient were analysed. IRB exemption was granted for this study. Conventional and stress wrist radiographs of 26 patients with and without a scapholunate ligament tear were retrospectively analysed to ascertain the range of variation in scapholunate diastasis. Speckle-tracking parameters in normal wrists were similar between the two readers (p > 0.2061). The maximal scapholunate peak strain during stress was relatively low (<0.34-0.47mm). The normal radiographic diastasis amplitude was similar to maximal strain peak values in normal volunteers (0.49 ± 0.51mm). The radiographic diastasis amplitude in cases of scapholunate ligament tears was 1.48 ± 0.78mm, which was higher than the 95% confidence interval of the scapholunate gap peak strain. Speckle-tracking sonography could represent an interesting alternative for stress evaluation of the scapholunate ligament in patients with scapholunate diastasis. • Speckle-tracking sonography can assess scapholunate diastasis under stress testing. • Scapholunate gap shows little variation under stress in healthy volunteers. • Scapholunate gap measurements are influenced by grip strength. • Sex and BMI have a significant influence on strain measurements.

Probiotics and Subclinical Psychological Symptoms in Healthy Participants: A Systematic Review and Meta-Analysis.

Interest in the gut-brain axis and emerging evidence that the intestinal microbiota can influence central nervous system function has led to the hypothesis that probiotic supplementation can have a positive effect on mood and psychological symptoms such as depression and anxiety. Although several human clinical trials have investigated this, results have been inconsistent. Therefore, a systematic review and meta-analytic approach was chosen to examine if probiotic consumption has an effect on psychological symptoms. The online databases PubMed, Scopus, and the Cochrane Library were searched for relevant studies up to July 2016. Those that were randomized and placebo controlled and measured preclinical psychological symptoms of depression, anxiety, and perceived stress in healthy volunteers pre and post supplementation with a probiotic were included. To control for differences in scales of measurement, data were converted to percentage change, and the standardized mean difference between the probiotic and control groups was investigated using Revman software. A random effects model was used for analysis. Heterogeneity was assessed using the I2 statistic. Quality assessment was undertaken using the Rosendal scale. Seven studies met the inclusion criteria and provided data for nine comparisons. All studies passed the quality analysis. The meta-analysis showed that supplementation with probiotics resulted in a statistically significant improvement in psychological symptoms (standardized mean difference 0.34; 95% confidence interval 0.07-0.61, Z = 2.49) compared with placebo. These results show that probiotic consumption may have a positive effect on psychological symptoms of depression, anxiety, and perceived stress in healthy human volunteers.