Clinical Physiology and Functional Imaging最新文献

Introduction: Neck and upper-back stiffness involves discomfort/ache in the trapezius muscle (TM). The pathogenesis of 'essential neck and upper-back stiffness' without obvious causes remains uncertain. In symptomatic subjects, TM hardness correlates with decreased transverse cervical artery (TCA) blood flow to the TM. Neck and upper-back stiffness could be associated with both hemodynamic and neurological factors affecting the TM. We therefore sonographically evaluated structural factors around the accessory nerve innervating the TM impacting neck and upper-back stiffness.

Methods: Participants comprised 69 healthy young adults (33 men, 36 women; 21 ± 1 y) who completed questionnaires and underwent elastography to determine TM hardness as a strain ratio and pulsed Doppler sonography to determine TCA hemodynamics. Intermuscular length was measured as the distance between sternocleidomastoid and levator scapulae muscles around the accessory nerve. Relationships of intermuscular length with symptoms, TM hardness, and TCA hemodynamics were analyzed.

Results: Intermuscular length was greater in symptomatic subjects (median 2.3 mm, interquartile range 1.5-3.1 mm) than in asymptomatic subjects (median 1.8 mm, interquartile range 1.5-2.3 mm; p = 0.032). Intermuscular length correlated positively with symptom severity (r = 0.43, p = 0.014) and negatively with strain ratio for the TM (r = -0.39, p = 0.025) and peak systolic velocity in the TCA (r = -0.40, p = 0.022). Intermuscular length contributed independently to the presence of symptoms (p = 0.025, odds ratio 2.26, 95% confidence interval 1.11-4.62).

Conclusion: In symptomatic subjects, symptom severity, TM hardness and TCA hemodynamics all correlated with greater intermuscular length. Structures around the accessory nerve could be associated with the pathogenesis of essential neck and upper-back stiffness.

Background: Skin water measurements are used to investigate skin physiology, clinically study dermatological issues, and for conditions like diabetes, oedema, and lymphedema with measurements done at various times of day (TOD). One method used is skin's tissue dielectric constant (TDC), often clinically measured to a single depth of 2.5 mm. This report characterizes intraday variations measured to multiple depths to guide expected TOD and depth dependence.

Materials and methods: Twelve medical students self-measured TDC on their forearm to depths of 0.5, 1.5, 2.5, and 5.0 mm every 2 h from 08:00 to 24:00 h on 2 consecutive days. All were trained in the procedure.

Results: TDC declined slightly from morning through evening, mostly at 0.5 mm for which TDC was reduced by 4%. TDC values were not related to participants' whole-body fat or water percentages. The TDC decrease was less at 1.5 mm where the reduction was 2.7%. At depths of 2.5 or 5.0 mm, there was no significant decrease in TOD.

Conclusion: Skin TDC shows a minor decreasing trend with an effect greater for shallower depths. In part, the clinical relevance of the findings relates to the confidence level associated with skin water estimates, based on TDC measurements, when measured at different TOD and depths during normal clinic hours. Based on the present data the TOD change is at most 4% and insignificant for measurement depths of 2.5 mm.

Introduction: Fat loss is often the target of weight loss interventions; however, preservation of lean soft tissue (LST) may be more important for health and weight maintenance. Though some LST loss may be inevitable when tracking body composition changes using dual-energy X-ray absorptiometry (DXA), correcting for the fat-free component of adipose tissue (FFAT) in DXA-derived LST (DXALST) has been proposed. This analysis sought to evaluate differences between DXALST and FFAT-corrected LST (FFATLST) amongst varied populations and interventions to understand application of the correction formula on LST outcomes.

Methods: 226 subjects were analyzed across five prior studies. Three studies evaluated combined nutrition and exercise (high-intensity interval training [HIIT] or high-intensity resistance training [HIRT]) interventions, including HIIT + HIRT with pre- and post-nutrient timing (HIITRT), HIIT + essential amino acids (HIITAA), and HIRT + protein (HIRTPRO). Remaining studies evaluated HIIT (HIITOW) and protein following bariatric surgery (BARPRO). Pre and post total body DXA scans were used to measure DXALST, body mass, and fat mass (FM). The correction formula was applied to calculate FFATLST. Paired sample t-tests were used to evaluate differences between DXALST and FFATLST change scores (Δ) across all subjects, within each study and intervention.

Results: Significant differences between ΔDXALST and ΔFFATLST were observed for BARPRO (mean difference [MD; ΔDXALST-ΔFFATLST] ± standard error [SE]: -3.5 ± 1.2 kg, p < 0.001), as well as HIRTPRO (-0.1 ± 0.2 kg, p = 0.004).

Discussion: When evaluating LST, the FFAT correction may be specifically applicable to cases of significant weight loss (>10% of original weight) or body recomposition (≥2% FM loss and ≥2% LST gain).

Background: Antihypertensives (AHD) can influence cerebral autoregulation (CA) and attenuate hypertrophic concentric remodelling of arterioles. The aim of this study was to examine the associations between AHD, CA and structural and functional properties of cerebral arteries.

Methods: In this observational, cross-sectional study 115 volunteers were divided in group 1 (non-hypertensive) [n = 30]; group 2 (hypertensive with systolic blood pressure [SBP] < 140 and diastolic blood pressure [DBP] < 90 mmHg) [n = 54]; group 3 (hypertensive with SBP ≥ 140 or DBP ≥ 90 mmHg) [n = 31] and simultaneous measurements of systemic blood pressure (BP) and middle cerebral artery blood flow velocity (CBFV) were obtained from digital plethysmography and transcranial Doppler. Beat-to-beat, critical closing pressure (CrCP), resistance-area product (RAP) and autoregulation index (ARI) values were extracted by linear regression analysis of instantaneous BP and CBFV waveforms using computerised analysis. Pulsatility index (PI) was calculated and CO₂ reactivity was assessed by the breath-holding test.

Results: Despite their higher RAP (1.7 [±0.7], p < 0.001) compared to groups 1 and 2, uncontrolled hypertensive using diuretics (p = 0.047) and α2-agonists (p = 0.009) had significantly lower PI. Impaired CO₂ reactivity was common between the two hypertensive groups (p = 0.008), however ARI, CrCP and CBFV did not differ between them and non-hypertensive individuals and also did not correlate with any AHD used.

Conclusions: Unlike the RAP, PI does not seem to reflect the real cerebrovascular resistence resulting from chronic arterial remodelling. Despite impaired CO₂ reactivity, hypertensive have arterial tonus and CA comparable to non-hypertensive. Experimental studies involving an untreated hypertensive control group are required to robustly make definitive conclusions about these questions.

Background: Near-infrared reactance spectroscopy (NIRS) has become increasingly popular in personal and professional settings now that it has been adapted to provide comprehensive body composition assessments. However, whether NIRS agrees with criterion methods remains unknown. Thus, this study aimed to determine the agreement between NIRS and DXA-derived body composition estimates.

Methods: Ninety-seven participants completed body composition assessments using DXA, and first-generation (NIRS_G1), second-generation (NIRS_G2), and muscle-specific NIRS (NIRS_FIT) devices. On a separate day, a subset of participants (n = 63) performed maximal voluntary contractions (MVC) on a handgrip dynamometer, which were used in conjunction with total appendicular lean mass (ALM) estimates to provide ratios (MVC/total ALM or MVC/ALM of the arms only) depicting muscle quality index (MQI).

Results: Fat mass, fat-free mass, body fat %, and ALM, from NIRS_G2, but not bone mineral content (BMC), and NIRS_FIT demonstrated equivalence (using equivalence tests) with DXA with R² from 0.83 to 0.97; though BMC revealed concordance coefficients of 0.83 and an R² of 0.88. MQI using total ALM from NIRS was not equivalent to DXA, but demonstrated low root mean squared error (0.08 kg/kg) and 95% limits of agreement (±0.21 kg/kg). Indices of visceral adipose tissue (iVAT) from NIRS_G1 and NIRS_G2 were significantly different (p < 0.001), but were both significantly associated with DXA VAT (NIRS_G1 R²: 0.53; NIRS_G2 R²: 0.62; both p < 0.001).

Conclusion: NIRS appears to demonstrate acceptable agreement with DXA and continual improvements could make NIRS a viable alternative for comprehensive body composition assessments.

Purpose: This study evaluated the relationship between HRV and echocardiography indices of cardiac function.

Methods: Healthy individuals (N = 30) aged 33 ± 10 years old, underwent short-term resting HRV assessment and transthoracic echocardiography with speckle tracking analysis. Time domain - (i.e. R-R interval, root mean square of successive RR interval difference (RMSSD), standard deviation of normal RR intervals (SDNN) and frequency domain-measures of HRV (i.e. high-frequency power (HF), low-frequency power (LF), high-frequency normalised (HFnorm) and low-frequency normalised (LFnorm)). Echocardiography indices of cardiac function included; Left ventricular ejection fraction (LVEF), left- and right-ventricular global longitudinal strain (LV-GLS, and RV GLS), left atrial strain: left atrial reservoir (LA_res), left atrial conduit (LA_con) and left atrial contraction (LA_CT).

Results: The mean values for HRV time-domain measures were: R-R (991 ± 176 ms), SDNN (50.9 ± 21.5 ms), and RMSSD (46.8 ± 29.4 ms); and frequency-domain: LF (727 ± 606 ms²), HF (415 ± 35 ms²), LFnorm (56 ± 19.4) and HFnorm (36.5 ± 18.8). Mean values for indices of cardiac function were LVEF (59.9% ± 2.8%), LV-GLS (19.2% ± 1.4%), RV-GLS (21.7% ± 2.7%), LA_res (36.8% ± 6.99%), LA_con (26.2% ± 6.95%) and LA_CT (12.3% ± 3.56%). There was a significant negative relationship between HF and LV-GLS (r = -0.47, p = 0.01) and RMSSD and LVEF (r = -0.39, p = 0.03) respectively.

Conclusion: Heart rate variability measures such as high frequency power and RMSSD are associated with left ventricle systolic function in healthy individuals.

Introduction: Plantar flexors play a pivotal role in human locomotion and balance. Several original research studies and systematic reviews have characterised the impact of single-leg disuse on plantar flexor strength and size. However, no meta-analysis has quantified the effects of single-leg disuse on changes in plantar flexor strength and size in uninjured adults.

Aim: To quantify changes in plantar flexor strength and size in response to single-leg disuse.

Methods: Data were extracted from 19 studies captured in our previous systematic review on studies that employed a unilateral lower limb immobilisation model (cast or brace) and were published up to January 30, 2022. Random-effects meta-analyses were performed on original research studies reporting measures of plantar flexor strength (isometric, isokinetic, or repetition maximum) and size (magnetic resonance imaging or computed tomography) in uninjured adults.

Results: Single-leg disuse decreased plantar flexor strength (Hedges g_av = -0.71 [95% confidence interval: -0.93, -0.48], p < 0.001, 7-28 days, N = 16 studies, n = 121 participants including ≥13 females, ages 19-29) and plantar flexor size (-0.33 [-0.50, -0.15], p < 0.001, 14-35 days, N = 6, n = 49, 10 females, ages 22-27) across all durations of disuse.

Discussion: Single-leg disuse decreases plantar flexor strength and size in uninjured adults. This work adds to recent meta-analytic findings demonstrating the declines in knee extensors strength and size following single-leg disuse. The paucity of female and participants >30 years old in the single-leg disuse literature examining plantar flexors represents a priority of future work.

Purpose: There is a scarcity of information regarding the effect of upper-body eccentric exercise on biomarkers of muscle damage. This study sought to investigate the effect of eccentric arm cycling on muscle damage [exercise-induced muscle damage (EIMD)].

Method: Ten subjects performed a 15 min eccentric arm cycling protocol (cadence 49 ± 7 rpm, power absorbed 248 ± 34 W). Maximal voluntary contraction (MVC) of the elbow flexors was evaluated at rest and at 5 min, 24 h, and 48 h post-exercise. In addition, blood samples were drawn at rest and thereafter at 30 min, 24 h, and 48 h intervals after exercise for quantification of creatine kinase (CK), myoglobin, lactate dehydrogenase (LDH) and endothelin (ET-1) concentrations. Delayed onset muscle soreness (DOMS) was assessed using a category ratio scale (0-10).

Results: Myoglobin was increased from baseline at 30 min post-exercise (+114%, 46.08 ± 22.17 µg/L, p = 0.018). Individual peak values were higher than baseline values for CK (+72.8%, 204 ± 138 U/L, p = 0.046) and LDH (+17%, 3.3 ± 0.88 nmole/min/mL, p = 0.017), but not for ET-1 (+9%, 1.4 ± 0.48 pg/mL, p = 0.45). DOMS was reported at 24 h (median 4) and 48 h (median 4) post-exercise and MVC of the elbow flexors were reduced from baseline (216 ± 44 N) at 5 min (-34%, 147 ± 61 N, p < 0.001), 24 h (-17%, 181 ± 56 N, p = 0.005) and 48 h (-9%, 191 ± 54 N, p = 0.003).

Conclusion: Eccentric arm cycling incites EIMD with reduced MVC and elevation of myoglobin, CK and LDH.

Background: Coronavirus disease 2019 (COVID-19) was declared a global pandemic in 2019. It remains uncertain to what extent COVID-19 effects the heart in heathy individuals. To evaluate the effect of the COVID-19 on cardiac structure and function in middle-aged and older individuals.

Methods: A single-centre prospective observational study enroled a total of 124 participants (84 with history of COVID-19 [COVID-19 group] and 40 without a history of COVID-19 [non-COVID group]). All participants underwent echocardiography with speckle tracking to assess cardiac structure and function at rest and during peak exercise.

Results: There were no differences in left and right ventricular diastolic function (p ≥ 0.05) between the COVID-19 and non-COVID-19 groups. Participants in COVID-19 group demonstrated higher left ventricular mass (130 ± 39.8 vs. 113 ± 27.2 g, p = 0.008) and relative wall thickness (0.38 ± 0.07 vs. 0.36 ± 0.13, p = 0.049). Left ventricular global longitudinal strain was reduced in the COVID-19 group at rest and at peak-exercise (rest: 18.3 ± 2.01 vs. 19.3 ± 1.53%, p = 0.004; peak exercise: 19.1 ± 2.20 vs. 21.0 ± 1.58%, p ≤ 0.001). However, no difference was seen in resting left ventricular ejection fraction (58 ± 2.89 vs. 59 ± 2.51%, p = 0.565) between groups. Right ventricular fractional area change was reduced in the COVID-19 group (p = 0.012).

Conclusion: Cardiac structural and functional remodelling was observed in middle-aged and older otherwise healthy individuals with a history of COVID-19.

Introduction: To determine whether heterogeneity in colorectal liver metastases (CRLM) ¹⁸F fluorodeoxyglucose [¹⁸F]FDG distribution is predictive of disease-free survival (DFS) and overall survival (OS) following liver transplantation (LT) for unresectable CRLM.

Methods: The preoperative [¹⁸F]FDG positron emission tomography/computed tomography examinations of all patients in the secondary cancer 1 and 2 studies were retrospectively assessed. Maximum standardized uptake value (SUV_max), metabolic tumour volume (MTV), and six texture heterogeneity parameters (joint entropy_GLCM, dissimilarity_GLCM, grey level variance_SZM, size zone variance_SZM, and zone percentage_SZM, and morphological feature convex deficiency) were obtained. DFS and OS for patients over and under the median value for each of these parameters were compared by using the Kaplan Meier method and log rank test.

Results: Twenty-eight out of 40 patients who underwent LT for unresectable CRLM had liver metastases with uptake above liver background and were eligible for inclusion. Low MTV (p < 0.001) and dissimilarity_GLCM (p = 0.016) were correlated to longer DFS. Low MTV (p < 0.001) and low values of the texture parameters dissimilarity_GLCM (p = 0.038), joint entropy_GLCM (p = 0.015) and zone percentage_SZM (p = 0.037) were significantly correlated to longer OS. SUV_max was not correlated to DFS and OS.

Conclusion: Although some texture parameters were able to significantly predict DFS and OS, MTV seems to be superior to predict both DFS and OS following LT for unresectable CRLM.