Artery Blood Flow Velocity Research Articles

Regular walking breaks prevent the decline in cerebral blood flow associated with prolonged sitting.

Decreased cerebrovascular blood flow and function are associated with lower cognitive functioning and increased risk of neurodegenerative diseases. Prolonged sitting impairs peripheral blood flow and function, but its effects on the cerebrovasculature are unknown. This study explored the effect of uninterrupted sitting and breaking up sitting time on cerebrovascular blood flow and function of healthy desk workers. Fifteen participants (10 male, 35.8 ± 10.2 yr, body mass index: 25.5 ± 3.2 kg/m2) completed, on separate days, three 4-h conditions in a randomized order: 1) uninterrupted sitting (SIT), 2) sitting with 2-min light-intensity walking breaks every 30 min (2WALK), or 3) sitting with 8-min light-intensity walking breaks every 2 h (8WALK). At baseline and 4 h, middle cerebral artery blood flow velocity (MCAv) and CO2 reactivity (CVR) of the MCA and carotid artery were measured using transcranial Doppler (TCD) and duplex ultrasound, respectively. Cerebral autoregulation (CA) was assessed with TCD using a squat-stand protocol and analyzed to generate values of gain and phase in the very low, low, and high frequencies. There was a significant decline in SIT MCAv (-3.2 ± 1.2 cm/s) compared with 2WALK (0.6 ± 1.5 cm/s, P = 0.02) but not between SIT and 8WALK (-1.2 ± 1.0 cm/s, P = 0.14). For CA, the change in 2WALK very low frequency phase (4.47 ± 4.07 degrees) was significantly greater than SIT (-3.38 ± 2.82 degrees, P = 0.02). There was no significant change in MCA or carotid artery CVR ( P > 0.05). Results indicate that prolonged uninterrupted sitting in healthy desk workers reduces cerebral blood flow; however, this is offset when frequent short-duration walking breaks are incorporated. NEW & NOTEWORTHY Prolonged uninterrupted sitting in healthy desk workers reduces cerebral blood flow. However, this reduction in cerebral blood flow is offset when frequent short-duration walking breaks are incorporated into this sitting period. For those who engage in long periods of sedentary behavior, chronically breaking up these sitting periods with frequent active break strategies may have important implications for cerebrovascular health; however, further research should explore this hypothesis.

Compromised dynamic cerebral autoregulation in patients with generalized anxiety disorder: a study using transfer function analysis

BackgroundPatients with generalized anxiety disorder (GAD) usually present with various neurological symptoms, but the mechanisms remain unclear. We aimed to analyze the characteristics of dynamic cerebral autoregulation (dCA) in patients with GAD.MethodsPatients (aged ≥18 years) who were diagnosed with GAD were enrolled in this study. Medically and psychiatrically healthy volunteers were recruited as controls. Subjects received the Hamilton Rating Scale for Anxiety (HAMA) and 17-item Hamilton Depression Rating Scale (HAMD) evaluation. Noninvasive continuous arterial blood pressure and bilateral middle cerebral artery blood flow velocity were recorded simultaneously from each subject. Transfer function analysis was used to derive the autoregulatory parameters, including phase difference, gain, and coherence function.ResultsA total of 57 patients with GAD and 40 healthy volunteers were enrolled. We found that the phase difference values were significantly compromised in patients with GAD. In the Spearman correlation analysis, the phase difference values were negatively correlated with the HAMA scores and the HAMD scores. In the multiple linear regression analysis, GAD is negatively correlated with the phase difference values, whereas age is positively correlated with the phase difference values.ConclusionsOur results suggested that the dCA was compromised in patients with GAD and negatively correlated with the score of anxiety. Improving the dCA may be a potential therapeutic method for treating the neurological symptoms of GAD patients.

Measurement of neurovascular coupling in human motor cortex using simultaneous transcranial Doppler and electroencephalography

Objective: Event-related desynchronization (ERD) is a relative power decrease of electroencephalogram (EEG) signals in a specific frequency band during physical motor execution, while transcranial Doppler (TCD) measures cerebral blood flow velocity. The objective of this study was to investigate the neurovascular coupling in the motor cortex by using an integrated EEG and TCD system, and to find any difference in hemodynamic responses in healthy young male and female adults. Approach: Thirty healthy volunteers, aged 20–30 years, were recruited for this study. The subjects were asked to perform a motor task for the duration of a provided visual cue. Simultaneous EEG and TCD recording was carried out using a new integrated system to detect the ERD arising from the EEG signals, and to measure the mean blood flow velocity of the left and right middle cerebral arteries from bilateral TCD signals. Main results: The results showed a significant decrease in EEG power in the mu band (7.5–12.5 Hz) during the motor task compared to the resting phase. It showed significant increase in desynchronization on the contralateral side of the motor task compared to the ipsilateral side. Mean blood flow velocity during the task phase was significantly higher in comparison with the resting phase at the contralateral side. The results also showed a significantly higher increase in the percentage of mean blood flow velocity in the contralateral side of motor task compared to the ipsilateral side. However, no significant difference in desynchronization or change of mean blood flow velocity was found between males and females. Significance: A combined TCD-EEG system successfully detects ERD and blood flow velocity in cerebral arteries, and can be used as a useful tool to study neurovascular coupling in the brain. There is no significant difference in the hemodynamic responses in healthy young males and females.

A predictive model for patients with median arcuate ligament syndrome.

Due to the rarity of median arcuate ligament (MAL) syndrome, patient selection for surgery remains difficult. This study provides a predictive model to optimize patient selection and predict outcomes following a MAL release. Prospective data from patients undergoing a MAL release included demographics, radiologic studies, and SF-36 questionnaires. Successful postoperative changes in SF-36 was defined as an improvement > 10% in the total SF-36 score. A logistic regression model was used to develop a clinically applicable table to predict surgical outcomes. Celiac artery (CA) blood flow velocities were compared pre- and postoperatively and Pearson correlations were examined between velocities and SF-36 score changes. 42 patients underwent a laparoscopic MAL release with a mean follow-up of 28.5 ± 18.8months. Postoperatively, all eight SF-36 scales improved significantly. The logistic regression model for predicting surgical benefit was significant (p = 0.0244) with a strong association between predictors and outcome (R2 = 0.36). Age and baseline CA expiratory velocity were significant predictors of improvement and predicted clinical improvement. There were significant differences between pre- and postoperative CA velocities. Postoperatively, the bodily pain scale showed the most significant increase (64%, p < 0.0001). A table was developed using age and preoperative CA expiratory velocities to predict clinical outcomes. Laparoscopic MAL produces significant symptom improvement, particularly in bodily pain. This is one of the first studies that uses preoperative data to predict symptom improvement following a MAL release. Age and baseline CA expiratory velocity can be used to guide postoperative expectations in patients with MAL syndrome.

A new method for visualizing pulmonary artery microvasculature using synchrotron radiation pulmonary microangiography: the measurement of pulmonary arterial blood flow velocity in the high pulmonary blood flow rat model.

Increased pulmonary blood flow (PBF) and shear stress may provoke irreversible vascular remodeling, yet invasive visualization of the microvasculature complicates monitoring. A non-invasive imaging methodology would therefore safely provide mechanistic insights into the progression of high PBF-induced vascular remodeling. To establish a novel microvasculature visualization method using synchrotron radiation pulmonary microangiography (SRPA) that can also calculate PBF velocity in vivo. A high PBF rat model was established by making a fistula between the abdominal aorta and inferior vena cava. After eight weeks, SRPA was performed and the dynamic density changes in the right lower pulmonary artery (PA) were calculated by software. SRPA was performed with a HARP (High-Gain Avalanche Rushing amorphous Photoconductor) receiver. PBF velocity was calculated by contrast medium transit time within the PA. All data were presented as mean ± standard error (SE). Student's t-test was used for comparison between the two groups. High dynamic spatial and contrast resolution from SRPA in the PA allowed for clear pulmonary microangiography and accurate detection of higher PBF in the rat model (82.3 ± 8.5 mm/s high-PBF group vs. 46.1 ± 4.3 mm/s control group, P < 0.01). These novel results demonstrate that SRPA was useful in both visualizing the dynamic flow distribution within the microvasculature and calculating PBF velocity. This newly developed, non-invasive technology may become a powerful tool in clarifying the mechanism of vascular remodeling associated with high PBF-induced shear stress.

Cerebral blood flow modulations during cognitive control in major depressive disorder

BackgroundThis study investigated cerebral blood flow modulations during proactive and reactive cognitive control in major depressive disorder (MDD). Proactive control refers to preparatory processes during anticipation of a behaviorally relevant event; reactive control is activated after such an event to ensure goal attainment. MethodsUsing functional transcranial Doppler sonography, blood flow velocities in the middle cerebral arteries of both hemispheres were recorded in 40 MDD patients and 40 healthy controls during a precued Stroop task. The font color of color words, which appeared 5 s after an acoustic warning signal, had to be indicated while ignoring word meaning. ResultsPatients, as compared to controls, exhibited smaller bilateral blood flow increases during task preparation and larger increases after color word presentation. Response time was longer in patients irrespective of the match or mismatch between font color and word meaning. The blood flow increase after word presentation correlated positively with response time. LimitationsPotential effects of psychotropic medication on cognition and cerebral blood flow could not be controlled. ConclusionsThe study revealed evidence of reduced cortical activity during proactive and elevated activity that occurs during reactive control in MDD. Deficient implementation of proactive control in MDD may lead to increased reliance on reactive control. The association between the blood flow increase after color word presentation and poorer performance indicates that deficient response preparation cannot be compensated for by reactive strategies. The findings are clinically relevant, as they may contribute to our understanding of the mechanisms relevant to cognitive impairments in MDD.

Cerebral Blood Flow Pulse Is Influenced By Ascending Aortic Flow During Acute Hypotension

PURPOSE: Recently, it has been suggested that cardiac function is one of important physiological factors to determine cerebral blood flow (CBF). However, dynamic relationship between cardiac outflow and CBF is still unknown. The purpose of the present study was to assess the dynamic relationship between arterial blood pressure (BP) or ascending aortic blood flow and CBF. METHODS: Six male healhy subjects participated (age, height, and weight; 33±6 yrs, 173±3 cm, and 72±8 kg) in the present study. Continuous beat-by-beat arterial BP was recorded from a finger using the Penaz method. Ascending aortic blood flow velocity (Ao-BFV) and middle cerebral artery blood flow velocity (MCA-BFV) were continuously measured using supra-sternum and transcranial Doppler ultrasound. After 10 min of resting condition, bilateral thigh cuffs were rapidly inflated to 200 mmHg and maintained for 2 min. Then both cuffs were rapidly deflated, and data were subsequently collected for 1 min. The same measurements were performed in the supine and 45-degree semi- Fowler’s positions. Pearson’s correlation coefficients were calculated to identify the relationship between relative change of BP or Ao-BFV and those of MCA-BFV among individuals. RESULTS: Correlation coefficient of mean BP and mean MCA-BFV was much larger than that of mean Ao-BFV and mean MCA-BFV in both the supine and semi-Fowler’s positions (R=0.615 vs. 0.009 and 0.353 vs. -0.753). In contrast, the correlation coefficient of pulse BP and pulse MCA-BFV was much smaller than that of pulse Ao-BFV and pulse MCA-BFV in the supine position (R=-0.068 vs 0.659), while it was comparable in the semi-Fowler’s position (R=0.555 vs 0.435). CONCLUSIONS: Dynamic change in mean CBF are likely to be only influenced by mean BP. However, dynamic change in pulse CBF seems to be more influenced by that of pulse ascending aortic blood flow rather than pulse BP especially in the supine position.

Effect of hyperbaric oxygen combined with nimodipine on treatment of diffuse brain injury.

The aim of the present study was to was investigate the treatment efficacy of hyperbaric oxygen (HBO) combined with nimodipine on diffuse brain injury. AA total of 80 patients with diffuse brain injury were randomly divided into four groups: Group A, conventional treatment; Group B, conventional treatment + nimodipine; Group C, conventional treatment + HBO therapy and Group D, conventional treatment + nimodipine + HBO therapy. The Glasgow Coma Scale (GCS) score and serum tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels were assessed before treatment and at 8, 24, 48 and 72 h after treatment. The bilateral middle cerebral arterial blood flow velocity (VmMCA) was measured by transcranial Doppler ultrasound. The results indicated that serum TNF-α and IL-1β were significantly decreased in all groups at 24, 48 and 72 h after treatment, compared with 8 h after treatment (P<0.05), with Group D exhibiting the largest decrease. The serum TNF-α, IL-1β and VmMCA peaked at 8 h and gradually decreased over the treatment period. VmMCA was decreased in Group B and D compared with Group A and C, and the decrease rate was higher in Group D compared with Group B (P<0.05). GCS scores were significantly increased in all groups at 24, 48 and 72 h after treatment compared with 8 h after treatment (P<0.05), with Group D exhibiting the largest increase. Serum TNF-α and IL-1β levels were positively correlated with VmMCA (P<0.05) and negatively correlated with GCS (P<0.05). Punctate hemorrhage was observed in all groups on CT before treatment, with a value of 66±3 HU. Punctate hemorrhage was observed to decrease over time in CT images, and CT values were significantly decreased in all groups at 8, 24, 48 and 72 h compared with before treatment (P<0.05). CT values were significantly lower in group D compared with groups A, B and C (P<0.05) at all time points. Serum TNF-α and IL-1β levels were positively correlated with CT value (P<0.05). In conclusion, HBO combined with nimodipine exhibited increased efficacy in the treatment of brain injury compared with either treatment alone.

Cerebral blood flow velocity in migraine and chronic tension-type headache patients.

IntroductionThe present study seeks to use transcranial Doppler ultrasound to evaluate cerebral blood flow velocities in anterior and posterior circulation arteries, during an attack-free episode in migraine patients, with and without aura, as well as in chronic tension-type headache patients who were not receiving prophylactic medication.MethodsA total of 50 patients (35 female, 15 male) were evaluated during a headache-free episode: 30 migraine patients without aura (mean age: 32±8 years), 10 migraine patients with aura (mean age: 34±4 years), and 10 patients with chronic tension-type headache (mean age: 34±5 years).ResultsNo significant difference was present between anterior, middle, and posterior cerebral and vertebral arteries’ blood flow velocities between migraine patients, with and without aura, or in patients with a tension-type headache, and normal controls (p>0.05). However, a significant increase in basilar artery cerebral blood flow velocities relative to controls was present in patients with a tension-type headache (p>0.001).ConclusionIt is difficult to predict the main reason for the significant increase in basilar artery blood flow velocities in patients with chronic tension-type headache. It may be due to constriction of conductance or the dilatation of the resistance vessels.

Cerebral autoregulation during exposure to artificial gravity

Our work has previously shown that exposure to artificial gravity (AG) can improve orthostatic tolerance. The purpose of this work is to examine whether cerebral autoregulation is improved with AG in twelve hypovolemic men and women. The protocol consisted of an initial ~45 minutes of a “step up” tolerance period, used to determine participants' presyncopal limit, followed by ~45 minutes training period at GZ below participants presyncopal limit. Beat‐by‐beat blood pressure (Portapres), heart rate (ECG), middle cerebral artery blood flow velocity (Transcranial Doppler) and end‐tidal carbon dioxide (capnography) were collected on participants during short arm centrifugation. Cerebral autoregulation was assessed using transfer function analysis between mean arterial pressure (MAP) and mean cerebral blood flow velocity (MCBFV) in 3‐min intervals during the training period. Exposure to AG resulted in a significant positive correlation between GZ and MAP, MAP variability and MCBFV variability in the low frequency (LF) range (0.07–0.15 Hz). In addition, coherence between MAP and MCBFV in the LF range was positively correlated. There was no change in gain and phase between MAP and MCBFV in the same frequency range. With higher GZ, there was a significant positive correlation in coherence and significant negative correlation in gain between MAP and MCBFV in the very low frequency range (0.03–0.07 Hz). These data suggest that increasing GZ exposure is correlated to increasing MAP variability. However, despite this increased MAP variability gain values demonstrated a negative correlation with GZ, suggesting that cerebral autoregulation tended to improve with increasing GZ exposure. We expect increased coherence was a result of the increased MAP variability associated with higher GZ. These data may suggest that exposure to AG may be helpful to improve cerebral autoregulation. Therefore, one could speculate that AG may be a useful tool to consider as a countermeasure for post‐flight astronauts to improve their orthostatic tolerance as well as cerebral autoregulation and improve re‐adaptation to a gravity environment.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cyclooxygenase Inhibition and Cerebrovascular Reactivity: Interaction of Aging and Aerobic Fitness

The ability of the cerebral microvessels to respond to chemical or metabolic stimuli declines with age and this change may be one mechanism through which age‐related cognitive decline occurs. Prostaglandins play an important role in the control of vascular tone, therefore changes in prostaglandin synthesis or expression may be underlying the age‐related alterations in cerebral microvascular function. Additionally, we have previously shown that aerobic fitness was associated with a decrease in cerebral microvascular function after cyclooxygenase (COX) blockade; yet this was in a small sample size of healthy older adults who were not exercise trained. Thus, the purpose of our study was to evaluate the effect of age on cerebral microvascular reactivity to hypercapnia (CVR) and to determine if habitual exercise modifies the response to COX blockade. We recruited 45 younger (YA; age = 26±1 y) and 31 older (OA; age = 63±1 y) healthy adults, including 21 sedentary YA, 24 exercising YA, 12 sedentary OA, and 19 exercising OA. Aerobic fitness (VO2 max) was measured during an incremental cycle ergometer test. Middle cerebral artery blood flow velocity (MCAv) and end‐tidal CO2 (ETCO2) were continuously recorded. CVR was calculated as the linear slope of the relationship between ETCO2 and MCAv and was assessed before and after the administration of the COX inhibitor indomethacin (INDO). The change in CVR was calculated as pre INDO CVR – post INDO CVR. There were no group differences in MCAv pre INDO (YA: 65±3 cm/s vs. OA: 59±3 cm/s; p&gt;0.05); however, YA had higher MCAv post INDO (YA: 45±1 cm/s vs. OA: 40±2 cm/s; p&lt;0.05). OA had significantly greater change in CVR compared with YA (2.0±0.1 cm/s/mmHg vs. 1.5±0.2 cm/s/mmHg, respectively; p&lt;0.05). There was also a significant effect of habitual exercise, such that sedentary adults had a greater change in CVR compared with exercising adults (2.0±0.2 cm/s/mmHg vs. 1.5±0.2 cm/s/mmHg, respectively; p&lt;0.05). In addition, there was an inverse association between VO2 max and the change in CVR in OA (r=0.42, p&lt;0.05), but not in YA (p&gt;0.05). Our results indicate that older adults, regardless of exercise status, rely more on COX‐derived products for cerebral microvascular responses to hypercapnia. Our results also suggest that habitual exercise may alter the contribution of COX‐derived products to cerebral blood flow regulation.Support or Funding InformationSupported by National Institute of Health grant HL118154This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Cerebrovascular Compliance is Affected by Posture

The mechanical properties of the arterial vascular wall influence the oscillatory component of flow through a vascular bed. Windkessel modeling has often been used to non‐invasively estimate these mechanical properties. While the systemic and coronary circulation have received considerable attention, the cerebral circulation represents a unique challenge because the oscillatory component of cerebral blood flow occurs within a pressurized and rigid skull. The present investigation evaluated the compliance of the cerebral vascular bed in comparison to that of the forearm vascular bed, a bed without significant extravascular pressure. Six young and healthy adults (24 ± 3 years, 5 females) were instrumented with a 3‐lead electrocardiogram, a finger photoplethysmograph (Finapres Medical Systems), and transcranial Doppler ultrasound (Multigon Industries) for continuous measures of heart rate, arterial blood pressure from the brachial artery, and cerebral blood flow velocity from the middle cerebral artery, respectively. Brachial artery blood flow velocity was also measured (duplex Doppler ultrasound; GE Healthcare). Following stabilization of hemodynamic variables, one to two minutes of data were collected in the supine posture. Measures were repeated after participants transitioned to a sitting posture, following re‐stabilization of variables. A modified Windkessel model was used to calculate the values of vascular compliance, as well as viscoelasticity and inertance effects, that are required to match the measured flow waveform to that predicted from the measured pressure waveform. Estimates of compliance were calculated for the forearm and cerebral vascular beds. In the supine posture, compliance of the cerebral vascular bed was lower than that of the forearm vascular bed by more than one order of magnitude (0.0006 ± 0.0005 vs. 0.002 ± 0.0007 mL/mmHg; P≤0.001; d=2.6). However, when seated, cerebrovascular compliance and forearm vascular compliance were not significantly different (0.002 ± 0.001 vs. 0.003 ± 0.002 mL/mmHg; P=0.10; d=1.0). The compliance in the brain increased considerably from the supine to sitting posture (P=0.03; d=0.91) but no significant difference was observed in the forearm (P=0.13; d=−0.65). The results suggest that intracranial pressure may prevent the cerebral vessels from exercising their compliance in supine. Further, as cerebrovascular compliance is increased with sitting, we speculate that posture‐induced reductions in cerebral venous volume affect cerebrovascular mechanics.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Countdown before voluntary exercise induces muscle vasodilation with decreased muscle sympathetic nerve activity in humans

We examined whether countdown (CD) before voluntary bicycle ergometer exercise induced cerebro‐cardiovascular responses and, if so, whether these responses to CD were altered by postural change from the semi‐recumbent to supine position. Young men (n=14) performed voluntary cycle exercise in the semi‐recumbent position while middle cerebral artery blood flow velocity (CBF; Doppler ultrasonography), heart rate (HR), blood pressure (finger photoplethysmography), oxygen consumption rate (VO2), oxygen saturation in the right thigh muscle (StO2; near‐infrared spectrometry), cardiac output (CO; cZ method) and total peripheral resistance (TPR) were measured. The subjects repeated 8 trials, intermitted by more than 5‐min rest. In 4 trials randomly selected from 8 trials, the onset of exercise was signaled by a 30‐sec CD, whereas in the remaining 4 trials, exercise was started without CD. We found that CD increased CBF, HR, CO, mean blood pressure, and VO2 sequentially, decreasing TPR with increased StO2. To assess efferent signals causing vasodilation and the effects of posture change from the semi‐recumbent to supine position, other groups of subjects underwent the same exercise protocol but using only right leg in the semi‐recumbent (n=10) or supine (n=8) positions while muscle sympathetic nerve activity (MSNA; microneurography) and StO2 were measured in the left and right leg, respectively. We found that CD decreased MSNA burst frequency and total MSNA (both, P&lt;0.05), which were significantly correlated with the increase in StO2 (both, P&lt;0.001). However, these responses to CD were nearly abolished by the postural change. Thus, CD before starting voluntary exercise induced cerebro‐cardiovascular responses from central system to effector organs in a sequential manner in the semi‐recumbent position, but these responses were minimized while in the supine position.Support or Funding InformationThis study was supported by grants from the Japan Society for the Promotion of Science (24689014 and 15H04680).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Dynamic Cerebral Autoregulation Impairment Persists Past Resolution of Symptoms in Collegiate Athletes Following Concussion

ObjectivesDespite 3.8 million concussions occurring annually in the United States, the pathophysiological sequelae of the injury are still poorly understood. Animal and human studies have consistently reported deficits in cerebral blood flow (CBF) following concussion suggesting impairments in CBF regulation. Reductions in CBF are also associated with functional outcomes. The purpose of the study was to examine dynamic cerebral autoregulation (dCA) in an ongoing prospective cohort of collegiate athletes 3 days, 21 days, and 90 days following a concussion and compare them with non‐injured controls.Materials and MethodsTwenty‐seven NCAA and recreational athletes (20±1 years) with a physician diagnosed sports‐related concussions were enrolled in the study. For the injured athletes, data was collected on days 3,21, and 90 following concussion. Twenty‐five age and sports matched non‐injured controls (20±1 years) were also enrolled. For non‐injured controls, data was collected at one time point. Symptom number and severity was measured using the Sports Concussion Assessment Tool (SCAT‐3). Depression scores were assessed with Patient Health Questionnaire‐9 (PHQ‐9). Continuous mean arterial blood pressure (MBP) was obtained with finger photoplethysmography and middle cerebral artery blood flow velocity (MCAV) was obtained with a 2 MHz transcranial Doppler ultrasonography while subjects were seated in an upright position. dCA was estimated from transfer function (Tf) analysis of beat‐to‐beat spontaneous fluctuations in MBP and MCAV within the low (LF, 0.07–0.20 Hz) and high (HF, 0.20–0.35 Hz) frequency ranges. Effective dCA would attenuate spontaneous changes in MCAV in response to variations in MBP, which would correspond to relatively low transfer function gain. Independent and paired t‐tests were used to compare dCA between days 3, 21, and 90 following concussion with the non‐injured controls.ResultsCompare to the controls, concussed athletes exhibited greater symptom number on day‐3 (12.2±6.8 vs. 2.4±3.4; p&lt;0.001) and higher PHQ‐9 score (8.7±5.6 vs. 2.1±2.1; p&lt;0.001). LF Tf gain was higher on day‐3 (1.26±0.34U vs. 1.04±0.28U; p=0.016) compared to the controls. LF Tf gain continued to be high on day‐21 (1.30±0.45U; p=0.025) compared to the non‐injured controls despite no differences in symptoms number or depression scores between the groups. LF Tf gain was comparable to the controls on day‐90.ConclusionsDynamic cerebral autoregulation appears to be impaired at least up to 21 days following concussion despite improvement in symptom and depression. Cerebral autoregulation estimated from transcranial Doppler ultrasonography may be useful as a potential vascular biomarker for return‐to‐play decisions following a concussion preventing the risk of second‐impact syndrome.Support or Funding InformationThis work was supported by SMU University Research Council Grant, Spring 2015 &amp; Texas Institute for Brain Injury and Repair (TIBIR) Pilot Grant 2016.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

End-to-side anastomosis for interrupted aortic arch in neonates and infants

Objective: To review the early and mid-term results of end-to-side anastomosis technique for interrupted aortic arch in neonates and infants. Methods: Clinic data of 46 patients were diagnosed as interrupted aortic arch in Department of Cardiac Surgery, Guangzhou Women and Children's Medical Center between January 2010 and December 2016 were analyzed retrospectively. Twenty-six cases were neonates. The median age underwent surgery was 23 days (range: 2 days to 8 years). Anatomical subtypes included 36 cases of type A and 10 cases of type B. There was no type C case. The reconstruction of the aortic arch was completed by an extended end-to-side anastomosis technique between the descending aorta and the undersurface of the proximal aortic arch. In 42 patients, all with intracardiac anomalies, had concomitant complete repair of intracardiac anomalies through a median sternotomy. The remaining 4 patients, all without intracardiac anomalies, an end-to-side anastomosis was constructed through a left thoracotomy. During follow-up, aortic arch recurrent obstruction, left ventricular outflow tract obstruction (LVOTO) and tracheal stenosis were focused. Results: There were 3 surgical deaths, with amortality rate of 6.5%. The remaining 43 patients survived after surgery. In 39 of these patients, deep hypothermic cardiac arrest (DHCA) strategy was used for brain protection, and the mean time of DHCA was (16±3) minutes. Eight patients underwent delayed sternal closure. The mean mechanical ventilation time and ICU stay time were (3.4±1.6) days (range: 2 to 12 days) and (6.4±2.7) days (range: 3 to 16 days) respectively. In 16 patients, all with tracheal or bronchial stenosis before surgery, mechanical ventilation was successfully evacuated, and no new airway stenosis occurred. There was no residual pressure difference between upper and lower extremity arterial blood pressure at discharge. Echocardiography showed normal arterial blood flow velocity in aortic arch. At a mean follow-up of (36.2±18.9) months (range: 6 months to 7 years), there were two patients lost and one late date. Four patients developed a recurrent stenosis at the aortic arch, of which two were severe, and the other two were mild. In 2 patients, both with mild LVOTO before surgery, no significant increase in the degree of obstruction was found during the follow-up. Two patients developed new mild to moderate LVOTO without clinical symptoms, and continued to follow up. In all patients, the tracheal or bronchial stenosis were extenuated, and there was no new progressive airway stenosis by regular bronchoscopy. Conclusions: The end-to-side anastomosis technique for the reconstruction of the aortic arch achieved excellent early and mid-term results in neonates and infants suffered from interrupted aortic arch. Reducing the anastomotic tension by extensive mobilization is the key to prevent postoperative early complications and late recurrent arch obstruction.

The Rate of Cerebral Blood Flow in the Clinic of Traumatology and Orthopedics

Assessed by ultrasound Doppler blood flow velocity (BFV) in middle cerebral arteries (MCA) reflects the state of the body of patients. A study of representative samples of healthy people of different age showed that the BFV has been steadily declining with increasing age. In healthy people, the BFV is reduced from 123 cm/ s at a rate 0,707 cm/s per year. The decline of 60% from the original values leads to disruption ofthecapacityof the centers in the brain and infact the entire body.The value of BFV in the MCA, as well as the life expectancy of women is higher than men’s, increased by 6% in chronic inflammatory diseases of the joints and reduced by 8% in the treatment of fractures of the limbs. However, these changes in patients almost affect the life expectancy of the patients. In patients with congenital violation of the natural growth of the limbs from childhood BFV in the MCA falls to 30%. In subsequent years, the pace of decline is slowing.

Hepatectomy increases metastatic graft and growth in an immunocompetent murine model of peritoneal metastases

BackgroundCurative surgery of synchronous peritoneal metastases (PM) and colorectal liver metastases (LM) has been recently investigated as feasible option. When synchronous peritoneal and liver resection is not achievable, the sequence of the surgery remains unknown. Our hypothesis was that liver resection (LR) promotes peritoneal growth resulting in a non-resectable PM. We sought to analyse the effects of major LR and liver regeneration after hepatectomy in a murine model of PM and the associated angiogenesis. MethodsMurine model of colorectal PM in Balb/C mice was developed by intraperitoneal injection of different CT-26 tumour cell concentrations. Five days after the injection, mice were randomized into three groups: 68% hepatectomy group, sham laparotomy and control group without surgery. On post-operative days 1, 5 and 20, PM was evaluated macroscopically, tumour growth and liver regeneration by immunohistochemistry, and angiogenesis by immunofluorescence. Circulating progenitor cells, plasmatic cytokines and digestive arterial blood flow velocity measurements were also analysed. ResultsReproducible murine model of limited colorectal PM was obtained. Surgery induced PM increases and promoted neo-angiogenesis. Major hepatectomy influence the tumour growth in the late phase after surgery, the extent of extra-peritoneal metastasis and the increase of Ki-67 expression in the remnant liver. ConclusionsThis animal model confirms the pro-tumoural and pro-angiogenic role of surgery, laparotomy and major LR, which promotes the increase of angiogenic factors and their participation in PM growth. These results suggest that peritoneal resection should be first step in the case of two-step liver and peritoneal surgery for patients with colorectal PM and LM.

Whole blood viscosity and cerebral blood flow velocities in obese hypertensive or obese normotensive adolescents.

Obesity affects all major organ systems and leads to increased morbidity and mortality. Whole blood viscosity is an important independent regulator of cerebral blood flow. The aim of the present study was to evaluate the effect of whole blood viscosity on cerebral artery blood flow velocities using transcranial Doppler ultrasound in pediatric patients with obesity compared to healthy controls and analyze the effect of whole blood viscosity and blood pressure status to the cerebral artery blood flow velocities. Sixty patients with obesity diagnosed according to their body mass index (BMI) percentiles aged 13-18 years old were prospectively enrolled. They were grouped as hypertensive or normotensive according to their ambulatory blood pressure monitoring. Whole blood viscosity and middle cerebral artery velocities by transcranial Doppler ultrasound were studied and compared to 20 healthy same aged controls. Whole blood viscosity values in hypertensive (0.0619±0.0077 poise) and normotensive (0.0607±0.0071 poise) groups were higher than controls (0.0616±0.0064 poise), with no significance. Middle cerebral artery blood flow velocities were higher in the obese hypertensive (73.9±15.0 cm/s) and obese normotensive groups (75.2±13.5 cm/s) than controls (66.4±11.5 cm/s), but with no statistical significance. Physiological changes in blood viscosity and changes in blood pressure did not seem to have any direct effect on cerebral blood flow velocities, the reason might be that the cerebral circulation is capable of adaptively modulating itself to changes to maintain a uniform cerebral blood flow.

Cerebral Vasoreactivity in Parkinson's Disease: A Pilot Study

Background: Cardiovascular autonomic failure is a frequent non-motor symptom of Parkinson’s disease (PD), its key feature being orthostatic hypotension (OH). Recent studies suggest that blood pressure deregulation in PD may be associated with increased cerebrovascular damage. Cerebral vasoreactivity (CVR) refers to the vasodilatory response of cerebral arterioles to elevation of pCO2. Reduced CVR is considered a risk factor for chronic cerebrovascular damage in the setting of hypertension or severe carotid artery stenosis. Here we evaluated CVR in PD patients with or without cardiovascular autonomic failure and age-matched healthy subjects. Methods: Transcranial doppler ultrasound was applied to measure blood flow velocity in the middle cerebral arteries of 12 PD patients and 11 healthy subjects. CVR was quantified by means of the breath holding index (BHI). OH was identified during a standing test, and in this setting blood flow velocities were likewise recorded. Results: PD patients displayed significantly lower BHI compared to controls, independently from the presence of OH. Patients with OH had lower mean arterial blood flow velocities compared to those without OH, both in supine and orthostatic position. Conclusions: These preliminary results show interactions between cerebral hemodynamics and blood pressure disturbances in PD, that may contribute to chronic cerebrovascular ischemic damage in PD.

Fenofibrate attenuates cardiac and renal alterations in young salt-loaded spontaneously hypertensive stroke-prone rats through mitochondrial protection.

The simultaneous presence of cardiac and renal diseases is a pathological condition that leads to increased morbidity and mortality. Several lines of evidence have suggested that lipid dysmetabolism and mitochondrial dysfunction are pathways involved in the pathological processes affecting the heart and kidney. In the salt-loaded spontaneously hypertensive stroke-prone rat (SHRSP), a model of cardiac hypertrophy and nephropathy that shows mitochondrial alterations in the myocardium, we evaluated the cardiorenal effects of fenofibrate, a peroxisome proliferator-activated receptor alpha (PPARα) agonist that acts by modulating mitochondrial and peroxisomal fatty acid oxidation. Male SHRSPs aged 6-7 weeks were divided in three groups: standard diet (n = 6), Japanese diet with vehicle (n = 6), and Japanese diet with fenofibrate 150 mg/kg/day (n = 6) for 5 weeks. Cardiac and renal functions were assessed in vivo by MRI, ultrasonography, and biochemical assays. Mitochondria were investigated by transmission electron microscopy, succinate dehydrogenase (SDH) activity, and gene expression analysis. Fenofibrate attenuated cardiac hypertrophy, as evidenced by histological and MRI analyses, and protected the kidneys, preventing morphological alterations, changes in arterial blood flow velocity, and increases in 24-h proteinuria. Cardiorenal inflammation, oxidative stress, and cellular senescence were also inhibited by fenofibrate. In salt-loaded SHRSPs, we observed severe morphological mitochondrial alterations, reduced SDH activity, and down-regulation of genes regulating mitochondrial fatty-acid oxidation (i.e. PPARα, SIRT3, and Acadm). These changes were counteracted by fenofibrate. In vitro, a direct protective effect of fenofibrate on mitochondrial membrane potential was observed in albumin-stimulated NRK-52E renal tubular epithelial cells. The results suggest that the cardiorenal protective effects of fenofibrate in young male salt-loaded SHRSPs are explained by its capacity to preserve mitochondrial function.