Diameter changes of the thoracic aorta caused by acute type B aortic dissection.

BACKGROUND: The impact of type B acute aortic dissection (TBAAD) on historical pre-TBAAD diameters of the thoracic aorta is rarely reported. The aim of this study was to assess the extent of changes in aortic diameters induced by dissection, measured with a computed tomography (CT) scan obtained before and after TBAAD. METHODS: Between January 2004 and December 2014, CT angiography of 50 non-Marfan patients with nonbicuspid aortic valves diagnosed with TBAAD were compared to historical CTs on file. RESULTS: The ascending aorta and proximal arch showed negligible change. The proximal, mid, and distal aorta diameters changed compared with predissected values (107.7 ± 4.8%, 109.3 ± 4.9%, and 105.7 ± 5.8%, respectively). Neither sex, false lumen status, or mural calcification, nor prior thoracoabdominal aortic ectasia, correlated with the diameter change. Age ≥80 years in the proximal descending aorta did correlate with the diameter change (110.7 ± 4.0% vs 106.1 ± 4.6% p = 0.01). CONCLUSIONS: Although identifying predicting factors for an aortic diameter increase all along with the thoracic aorta was still challenging, the degree of diameter change by aortic dissection was 105.7% to 109.3% in descending thoracic aorta, most prominent in middle descending aorta.

Parents regulate arousal while sharing experiences with their child: a study of pupil diameter change responses.

Introduction: Parents provide their children with their first exposures to reciprocal shared experiences, and parental modeling of socio-emotional behaviors and regulatory responses largely influences their child's behavioral and neurological development. Some parental reactions are conscious, while others are non-volitional. This project aimed to explore parent-child pupil dilation change responses during shared interactions, specifically, whether parents' neuro-regulatory responses when sharing experiences with their child are different than responses of children interacting with their parents or children and adult peers sharing with each other. Methods: To test this, four distinct interacting groups were recruited: (1) Parents sharing with their child; (2) Children sharing with their parent; (3) Children sharing with peers; and (4) Adults sharing with peers. All dyads engaged in a computerized shared imagery task, which facilitates communication and mental imagery during a shared experience. During the task, pupil diameter change was recorded as a measure of regulatory response. Results: Findings highlight that parents sharing with their child have lower pupil diameter change than children sharing with their parents (p < 0.01), children sharing with peers (p < 0.01), and adults sharing with peers (p < 0.05), While no differences were seen between children sharing with parents, children sharing with peers or adults sharing with peers. Discussion: Findings deepen the understanding of the neuroscience of parenting, by suggesting that parents, even of older children and adolescents, tend to regulate their arousal when interacting with their child, a response that proves to be unique compared to other dyad types for sharing experiences. Considering this dynamic, findings may direct future parent-led intervention methods to improve the child's socio-emotional development.

Nocturnal sap flow as compensation for water deficits: an implicit water-saving strategy used by mangroves in stressful environments.

As part of the plant water-use process, plant nocturnal sap flow (Q n) has been demonstrated to have important ecophysiological significance to compensate for water loss. The purpose of this study was to explore nocturnal water-use strategies to fill the knowledge gap in mangroves, by measuring three species co-occurring in a subtropical estuary. Sap flow was monitored over an entire year using thermal diffusive probes. Stem diameter and leaf-level gas exchange were measured in summer. The data were used to explore the different nocturnal water balance maintaining mechanisms among species. The Q n existed persistently and contributed markedly over 5.5%~24.0% of the daily sap flow (Q) across species, which was associated with two processes, nocturnal transpiration (E n) and nocturnal stem water refilling (R n). We found that the stem recharge of the Kandelia obovata and Aegiceras corniculatum occurred mainly after sunset and that the high salinity environment drove higher Q n while stem recharge of the Avicennia marina mainly occurred in the daytime and the high salinity environment inhibited the Q n. The diversity of stem recharge patterns and response to sap flow to high salinity conditions were the main reasons for the differences in Q n/Q among species. For Kandelia obovata and Aegiceras corniculatum, R n was the main contributor to Q n, which was driven by the demands of stem water refilling after diurnal water depletion and high salt environment. Both of the species have a strict control over the stomata to reduce water loss at night. In contrast, Avicennia marina maintained a low Q n, driven by vapor pressure deficit, and the Q n mainly used for E n, which adapts to high salinity conditions by limiting water dissipation at night. We conclude that the diverse ways Q n properties act as water-compensating strategies among the co-occurring mangrove species might help the trees to overcoming water scarcity.

Comparison of the multi-phasic longitudinal displacement of the left and right common carotid artery in healthy humans.

BACKGROUND: During the cardiac cycle, there is a multi-phasic bidirectional longitudinal movement (LMov) of the intima-media complex of large arteries, i.e. along the arteries. On the left side the common carotid artery (CCA) arises directly from the aortic arc, whereas on the right side the CCA originate from the innominate artery. AIM: The aim of this study was to compare LMov of the left and right CCA of healthy subjects to investigate whether the difference in anatomy is of importance for LMov. MATERIAL AND METHODS: The CCA's of 93 healthy subjects were investigated using in-house developed ultrasound methods. RESULTS: Although the basic pattern were the same in the majority of subjects, several phases of LMov were significantly larger on the left side (the first retrograde phase, p = 0.0006; the second antegrade, "returning" phase, p < 0.00001; and the rapid retrograde phase of movement at the end of the cardiac cycle, p < 0.000001). In contrast, no significant side-difference in the amplitude of the first antegrade movement was seen. The maximal (peak-to-peak) LMov was significantly larger on the left side (p = 0.002). DISCUSSION AND CONCLUSION: The side-differences found in LMov may be related to the difference in anatomy, including possible difference in distance to the heart and especially the presence of an extra bifurcation on the right side. Our data provide an important base for the further study of the relation between LMov and cardiovascular risk factors and atherosclerosis.

Comparison of Four Haemodynamic Tests that Quantify Superficial Venous Insufficiency.

OBJECTIVES: Reflux assessment with ultrasound (U/S) is usually qualitative. Quantitative measurements of superficial venous insufficiency (SVI) include the venous arterial flow index (VAFI), recirculation index (RCI), venous filling index (VFI), and the postural diameter change (PDC) of the saphenous trunk. The aim was to investigate their relationship. MATERIALS AND METHODS: This was an observational study performed on patients with varicose veins and hospital employees. Four haemodynamic parameters were measured in 21 legs from 16 subjects. Legs were divided into no reflux (n = 7) and reflux (n = 14). The VAFI is the U/S ratio of common femoral vein volume flow divided by the common femoral artery volume flow, performed supine. The RCI is the U/S ratio of reflux volume over antegrade volume within the saphenous trunk after calf compression, standing. The VFI is the rate of calf volume increase on dependency measured in mL/s, using air plethysmography. The PDC is the percentage reduction of the saphenous trunk diameter from standing to lying, using U/S. RESULTS: The clinical part of the CEAP classification was: C0 = 3, C1 = 4, C2 = 5, C3 = 1, C4a = 1, C4b = 6, C5 = 1. All four tests demonstrated significant differences between the two groups with minimal overlap (Mann Whitney U test): VAFI (p = .028), RCI (p < .0005), VFI (p = .001), and PDC (p = .014). Furthermore, significant correlations were observed with the tests: VAFI vs. RCI (r = .532, p = .015), VFI (r = .489, p = .025) and PDC (r = -.474, p = .030); RCI vs. VFI (r = .446, p = .043) and PDC (r = -.527, p = .014). CONCLUSIONS: Superficial venous drainage insufficiency should not be confined to an U/S assessment of the presence of reflux, which is qualitative. Quantitative data may be provided using the VAFI, RCI, VFI, and PDC. Understanding why there are significant correlations among these parameters and the preferred objective reference test requires further work.

Which Body Position Is the Best for Chest Wall Motion in Healthy Adults? A Meta-Analysis.

BACKGROUND: Chest wall motion is a vital component of the respiratory system. Body position changes disturb joint orientation around the chest wall and results in performance modifications of respiratory muscles and movement surrounding the rib cage and the abdomen. Body position is a priority treatment for preserving and promoting chest wall motion. The objective of the study was to conduct a meta-analysis to provide insight into which body position most effectively improves chest wall motion. METHODS: Medical literature databases were systemically searched up to January 31, 2018. Methodological quality was evaluated by using a checklist for measuring quality. A meta-analysis was performed to evaluate the effects of body positions on chest wall motion. The quality of evidence was judged by using the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) approach. RESULTS: Six studies (5 high- and 1 low-quality) were identified. Our results showed that the sitting position provided greater improvement in chest-wall diameter changes and volume related to rib-cage function versus other body positions (very low to moderate evidence). The supine position demonstrated greater enhancement of chest-wall-diameter changes and volume in the part of the abdomen than the other body positions with very low to moderate evidence. CONCLUSIONS: The results of this review indicated that the sitting position improved the rib-cage compartment of the chest wall, whereas the supine position resulted in the superior enhancement in the part of the abdomen relative to other body positions. These changes in the body position could have some effect on the movements of the rib cage and abdomen and the variations in lung volumes, which need to be interpreted with caution when considering implementation in the clinical setting.

Water relations in silver birch during springtime: How is sap pressurised?

Positive sap pressures are produced in the xylem of birch trees in boreal conditions during the time between the thawing of the soil and bud break. During this period, xylem embolisms accumulated during wintertime are refilled with water. The mechanism for xylem sap pressurization and its environmental drivers are not well known. We measured xylem sap flow, xylem sap pressure, xylem sap osmotic concentration, xylem and whole stem diameter changes, and stem and root non-structural carbohydrate concentrations, along with meteorological conditions at two sites in Finland during and after the sap pressurisation period. The diurnal dynamics of xylem sap pressure and sap flow during the sap pressurisation period varied, but were more often opposite to the diurnal pattern after bud burst, i.e. sap pressure increased and sap flow rate mostly decreased when temperature increased. Net conversion of soluble sugars to starch in the stem and roots occurred during the sap pressurisation period. Xylem sap osmotic pressure was small in comparison to total sap pressure, and it did not follow changes in environmental conditions or tree water relations. Based on these findings, we suggest that xylem sap pressurisation and embolism refilling occur gradually over a few weeks through water transfer from parenchyma cells to xylem vessels during daytime, and then the parenchyma are refilled mostly during nighttime by water uptake from soil. Possible drivers for water transfer from parenchyma cells to vessels are discussed. Also the functioning of thermal dissipation probes in conditions of changing stem water content is discussed.

Influence of bronchial diameter change on the airflow dynamics based on a pressure-controlled ventilation system.

Bronchial diameter is a key parameter that affects the respiratory treatment of mechanically ventilated patients. In this paper, to reveal the influence of bronchial diameter on the airflow dynamics of pressure-controlled mechanically ventilated patients, a new respiratory system model is presented that combines multigeneration airways with lungs. Furthermore, experiments and simulation studies to verify the model are performed. Finally, through the simulation study, it can be determined that in airway generations 2 to 7, when the diameter is reduced to half of the original value, the maximum air pressure (maximum air pressure in lungs) decreases by nearly 16%, the maximum flow decreases by nearly 30%, and the total airway pressure loss (sum of each generation pressure drop) is more than 5 times the original value. Moreover, in airway generations 8 to 16, with increasing diameter, the maximum air pressure, maximum flow, and total airway pressure loss remain almost constant. When the diameter is reduced to half of the original value, the maximum air pressure decreases by 3%, the maximum flow decreases by nearly 5%, and the total airway pressure loss increases by 200%. The study creates a foundation for improvement in respiratory disease diagnosis and treatment.

Postural Diameter Change of the Saphenous Trunk in Chronic Venous Disease.

OBJECTIVE: The aim of this study was to analyze the correlation between the extent of diameter change from standing to supine position ("postural diameter change," PDC), and patient or duplex ultrasound (DUS) characteristics in lower limbs with and without saphenous trunk (ST) reflux. METHODS: Measurements were carried out in 193 limbs with primary great saphenous vein, anterior accessory saphenous vein, or small saphenous vein reflux, and 48 control limbs without ST reflux. The inner diameter of the ST was measured with DUS in the standing and lying positions. The PDC, calculated as a percentage, followed the formula: (standing diameter - lying diameter)/standing diameter × 100. Clinical findings (according to the highest "C" - of the CEAP classification), venous clinical severity score, body mass index (BMI), time of visit, and inside and outside temperature were documented. Limbs were divided into two groups using the median value of PDC as a cut off to increase interpretability of the analysis. RESULTS: The median PDC of the ST was 19% in limbs with ST reflux compared with 24% in control limbs (p = .16). In limbs with and without ST reflux, only older age and increased BMI were independently associated with a low PDC of the ST (R(2) 0.13). In limbs with ST reflux, median PDC was significantly lower in C4-C6 (16%, interquartile [IQR] 8-21) than in C0-C1 (23%, IQR 12-35) or C2-C3 limbs (21%, IQR 11-33; p = .016). In addition, PDC was significantly lower in veins with a large diameter (>7 mm) than in those with a small diameter (p = .003). CONCLUSION: Low PDC of the ST correlates with older age and increased BMI. Whether PDC might become a useful additional DUS tool to classify the severity of chronic venous disease and thereby influence the management strategy should be further investigated.