Near-infrared spectrophotometry determined brain oxygenation during fainting

During orthostatic hypotension we evaluated whether presyncopal symptoms relate to a reduced brain oxygenation. Nine subjects performed 50° head-up tilt for 1 h and eight subjects were followed during 2 h of supine rest and during 1 h of 10° head-down tilt. Cerebral perfusion was assessed by transcranial Doppler determined middle cerebral artery blood velocity (MCA v_mean), while brain blood oxygenation was assessed by near-infrared spectrophotometry determined concentration changes for oxygenated (ΔHbO₂) and deoxygenated haemoglobin and brain cell oxygenation by the oxidized cytochrome c concentration (ΔCytO₂). During head-up tilt, six volunteers developed presyncopal symptoms and mean arterial pressure (88 (78–103) to 68 (57–79) mmHg; median and range), heart rate (96 (72–111) to 65 (50–107) beats min^?1), MCA v_mean (59 (51–82) to 41 (29–56) cm s^?1), ΔHbO₂ (by ?5.3 (?3.0 to ?14.8) μmol l^?1) and ΔCytO₂ were reduced (by ?0.2 (?0.1 to ?0.4) μmol l^?1; P < 0.05). During tilt down the cardiovascular variables recovered immediately and ΔHbO₂ increased to 2.2 (?0.9–12.0) mmol L^?1 above the resting value and also ΔCytO₂ recovered. In the nonsyncopal head-up tilted subjects as in the controls, blood pressure, heart rate, MCA v_mean and brain oxygenation indices remained stable. The results suggest that during orthostasis, presyncopal symptoms relate not only to cerebral hypoperfusion but also to reduced brain oxygenation.     

Middle cerebral artery blood velocity depends on cardiac output during exercise with a large muscle mass

We tested the hypothesis that pharmacological reduction of the increase in cardiac output during dynamic exercise with a large muscle mass would influence the cerebral blood velocity/perfusion. We studied the relationship between changes in cerebral blood velocity (transcranial Doppler), rectus femoris blood oxygenation (near-infrared spectroscopy) and systemic blood flow (cardiac output from model flow analysis of the arterial pressure wave) as induced by dynamic exercise of large (cycling) vs. small muscle groups (rhythmic handgrip) before and after cardioselective β₁ adrenergic blockade (0.15 mg kg^?1 metoprolol i.v.). During rhythmic handgrip, the increments in systemic haemodynamic variables as in middle cerebral artery mean blood velocity were not influenced significantly by metoprolol. In contrast, during cycling (e.g. 113 W), metoprolol reduced the increase in cardiac output (222 ± 13 vs. 260 ± 16%), heart rate (114 ± 3 vs. 135 ± 7 beats min^?1) and mean arterial pressure (103 ± 3 vs.112 ± 4 mmHg), and the increase in cerebral artery mean blood velocity also became lower (from 59 ± 3 to 66 ± 3 vs. 60 ± 2 to 72 ± 3 cm s^?1; P < 0.05). Likewise, during cycling with metoprolol, oxyhaemoglobin in the rectus femoris muscle became reduced (compared to rest; ?4.8 ± 1.8 vs. 1.2 ± 1.7 μmol L^?1, P < 0.05). Neither during rhythmic handgrip nor during cycling was the arterial carbon dioxide tension affected significantly by metoprolol. The results suggest that as for the muscle blood flow, the cerebral circulation is also affected by a reduced cardiac output during exercise with a large muscle mass.     

基于抗肝纤维化生物活性及近红外谱效相关的鳖甲质量评价研究

目的 从鳖甲临床抗肝纤维化功效出发并结合近红外光谱,探索建立关联抗肝纤维化活性的鳖甲质量生物活性评价方法。方法 建立转化生长因子-β1（transforming growth factor-β1,TGF-β1）诱导的LX-2肝纤维化细胞模型,采用qRT-PCR检测鳖甲对I型胶原（type I collagen,COL1）mRNA表达的影响,计算鳖甲对COL1 mRNA相对表达量的抑制率;采用Western blotting检测鳖甲对COL1蛋白表达的影响,以评价鳖甲在细胞模型上的抗肝纤维化生物活性。采集并处理不同批次鳖甲药材的近红外光谱数据,通过谱-效相关分析探究鳖甲药材近红外光谱数据与其抗肝纤维化活性的相关性,筛选活性波段,建立鳖甲的效应近红外谱,以效应近红外谱下面积评价鳖甲药材的质量。结果 体外实验表明,与模型组比较,鳖甲水提物（water extract of Trionycis Carapax,WECT）处理组细胞中COL1 mRNA与蛋白表达水平显著下调（P＜0.05、0.01）;基于谱-效相关分析,共筛选得到R＞0.6、P＜0.05且波数大于8 cm⁻¹的活性波段3个,分别为5226～5235 cm⁻¹、5943～6071 cm⁻¹与6379～6396 cm⁻¹,以3个活性波段下面积为指标,建立鳖甲药材的效应近红外谱,计算各特征波段下面积和,并分析其与生物活性的相关性,两者相关系数R为0.813 53。结论 WECT可抑制LX-2细胞外基质的产生来治疗肝纤维化;效应波谱下面积和（5226～5235 cm⁻¹、5943～6071 cm⁻¹与6379～6396 cm⁻¹）作为鳖甲药材的质量评价系数,用于评价鳖甲药材的质量,可区分不同批次鳖甲药材的抗肝纤维化活性。     

Indocyanine green fluorescence imaging for laparoscopic complex upper urinary tract reconstructions: a comparative study

BackgroundTo describe our technique for using an intraureteral injection of indocyanine green (ICG) and visualization under near-infrared fluorescence (NIRF) to facilitate challenging upper urinary tract reconstructions (UUTRs) and to present the comparative outcomes.MethodsWe collected 36 patients who underwent laparoscopic UUTRs between April 2019 and March 2020, and we divided the patients into two groups based on the use of ICG (ICG group and non-ICG group). Demographic characteristics, perioperative outcomes, and functional outcomes were compared between the two groups.ResultsThere were 18 cases in the ICG group and 18 cases in the non-ICG group, respectively. There were no differences in the baseline characteristics between the two groups. The intraoperative time to identification of the ureter (TIU; 20.9±11.7 vs. 30.0±14.6 min, P=0.03) and length of postoperative hospital stay (LPHS; 11.1±3.0 vs. 16.6±10.0 days, P=0.03) were significantly shorter in the ICG group. There was also a trend for lesser time for locating the stricture (43.0±27.9 vs. 55.4±18.6 min, P=0.14) and lower estimated blood loss (EBL) in the ICG group patients (88.3±75.4 vs. 91.7±46.2 mL, P=0.22). During the mean 3.8-month follow-up for the ICG group and the 6.2-month for the non-ICG group, there was a trend for more severe complications in the non-ICG group.ConclusionsVisualizing intraureteral ICG under NIRF is useful in challenging UUTRs, allows for rapid ureteral identification and accurate real-time delineation of the ureteral stricture margins, and provides encouraging follow-up outcomes compared with those in the non-ICG group.     

Prefrontal activation in preschool children is associated with maternal adversity and child temperament: A preliminary fNIRS study of inhibitory control

Exposure to adversity is a well-documented risk factor for cognitive, behavioral, and mental health problems. In fact, the consequences of adversity may be intergenerational. A growing body of research suggests that maternal exposures to adversity, including those prior to childbirth, are associated with offspring biobehavioral development. In a sample of 36 mothers and their preschool-age children (mean child age = 4.21 ± 0.92 years), we used functional near-infrared spectroscopy to replicate and extend this work to include brain activation during inhibitory control in young children. We found that measures of maternal exposure to adversity, including cumulative, childhood, and preconception exposures, were significantly and positively associated with activation in the right frontopolar prefrontal cortex (PFC) and in the left temporal and parietal clusters during inhibitory control. In addition, and consistent with previous findings, children's increased negative affect and decreased effortful control were associated with increased right PFC activation during inhibitory control. These findings provide preliminary evidence that maternal and dispositional risk factors are linked to alterations in PFC functioning during the preschool years. Children of mothers with a history of exposure to adversity, as well as children who are less temperamentally regulated, may require increased neural resources to meet the cognitive demands of inhibitory control.     

小波变换-人工神经网络用于烟酸片的近红外快速、无损定量测定

目的：研究采用近红外漫反射光谱法结合小波变换-人工神经网络算法用于烟酸片的无损含量测定。方法：所有光谱通过载有InGaAs检测器和光纤探头的傅立叶变换近红外装置获得。所有样品在12000cm^-1到4000cm^-1扫描，每个样品光谱扫描64次，光谱预处理采用一阶导数。特定波段7999．599～3999．8cm^-1用于建模，线性范围：50％～150％。结果：预示集平均回收率100．06％，RSD％为1．5。为确证近红外漫反射光谱法应用的可行性，预示集与参比方法紫外分光光度法测定结果进行比较，采用配对比较t检验，近红外法与紫外光谱法比较无显著性差异。结论：近红外漫反射光谱法快速，简便，无损，能够用于烟酸片含量测定。     

Validation of diffuse correlation spectroscopy against 15O-water PET for regional cerebral blood flow measurement in neonatal piglets

Diffuse correlation spectroscopy (DCS) can non-invasively and continuously asses regional cerebral blood flow (rCBF) at the cot-side by measuring a blood flow index (BFI) in non-traditional units of cm²/s. We have validated DCS against positron emission tomography using ¹⁵O-labeled water (¹⁵O-water PET) in a piglet model allowing us to derive a conversion formula for BFI to rCBF in conventional units (ml/100g/min). Neonatal piglets were continuously monitored by the BabyLux device integrating DCS and time resolved near infrared spectroscopy (TRS) while acquiring ¹⁵O-water PET scans at baseline, after injection of acetazolamide and during induced hypoxic episodes. BFI by DCS was highly correlated with rCBF (R = 0.94, p < 0.001) by PET. A scaling factor of 0.89 (limits of agreement for individual measurement: 0.56, 1.39)×10⁹× (ml/100g/min)/(cm²/s) was used to derive baseline rCBF from baseline BFI measurements of another group of piglets and of healthy newborn infants showing an agreement with expected values. These results pave the way towards non-invasive, cot-side absolute CBF measurements by DCS on neonates.     

Recovery of cortical functioning in abstinent alcohol-dependent patients: Prefrontal brain oxygenation during verbal fluency at different phases during withdrawal

Abstract

Objectives. Neurotoxic effects of alcohol consumption are well-known. There is plenty of literature on frontal lobe impairment on the behavioural and structural brain imaging level. However, only few functional imaging studies investigated altered neural patterns and even less abstinence-related neural recovery. Methods. In a cross-sectional design three patient groups (acute withdrawal, detoxified, abstinent) and healthy controls (each n = 20) performed a phonological and semantic verbal fluency task (VFT) while brain activity was measured with near-infrared spectroscopy (NIRS). Results. First, for the phonological condition withdrawal patients and detoxified patients showed less fluency-related frontal lobe activation compared to controls despite equal performance. Second, significant linear trend effects from withdrawal patients over detoxified and abstinent patients up to healthy controls indicated more normal activation patterns in the abstinent group that did not differ significantly from the controls. In the detoxified group brain activation increased with time since detoxification. Conclusions. Our results are compatible with an increase in frontal brain activity from alcohol dependence over abstinence up to normal functioning. However, as cross-sectional designs do not allow to assess causal relations, results have to be considered preliminary and longitudinal studies are needed to further elucidate recovery processes in alcohol dependence.