Thrombin Generation in Zebrafish Blood

To better understand hypercoagulability as an underlying cause for thrombosis, the leading cause of death in the Western world, new assays to study ex vivo coagulation are essential. The zebrafish is generally accepted as a good model for human hemostasis and thrombosis, as the hemostatic system proved to be similar to that in man. Their small size however, has been a hurdle for more widespread use in hemostasis related research. In this study we developed a method that enables the measurement of thrombin generation in a single drop of non-anticoagulated zebrafish blood. Pre-treatment of the fish with inhibitors of FXa and thrombin, resulted in a dose dependent diminishing of thrombin generation, demonstrating the validity of the assay. In order to establish the relationship between whole blood thrombin generation and fibrin formation, we visualized the resulting fibrin network by scanning electron microscopy. Taken together, in this study we developed a fast and reliable method to measure thrombin generation in whole blood collected from a single zebrafish. Given the similarities between coagulation pathways of zebrafish and mammals, zebrafish may be an ideal animal model to determine the effect of novel therapeutics on thrombin generation. Additionally, because of the ease with which gene functions can be silenced, zebrafish may serve as a model organism for mechanistical research in thrombosis and hemostasis.     

Repeated Blood Collection for Blood Tests in Adult Zebrafish

Repeated blood collection is one of the most common techniques performed on laboratory animals. However, a non-lethal protocol for blood collection from zebrafish has not been established. The previous methods for blood collection from zebrafish are lethal, such as lateral incision, decapitation and tail ablation. Thus we have developed a novel “repeated” blood collection method, and present here a detailed protocol outlining this procedure. This method is minimally invasive and results in a very low mortality rate (2.3%) for zebrafish, thus enabling repeated blood sampling from the same individual. The maximum volume of blood sampling is dependent on body weight of the fish. The volume for repeated blood sampling at intervals should be ≤0.4% of body weight every week or ≤1% every 2 weeks, which were evaluated by measurements of blood hemoglobin. Additionally, hemoglobin, fasting blood glucose, plasma triacylglycerol (TG) and total cholesterol levels in male and female adult zebrafish were measured. We also applied this method to investigate the dysregulation of glucose metabolism in diet-induced obesity. This blood collection method will allow many applications, including glucose and lipid metabolism and hematological studies, which will increase the use of zebrafish as a human disease model organism.     

Blood Circulation Pattern in Highly Skilled Swimmers

Echocardiography was used to study the parameters of cardiodynamics, systemic hemodynamics, left ventricular morphology and functioning, phase analysis of cardiac activity, and rheological blood properties in highly skilled expert swimmers. The relationship between different levels of blood circulation was established. A close correlation between the blood flow at rest and arterial pressure was found to contribute to the optimization of microvascular pressure and shear stress in accordance with body demands.     

Blood Flow Changes Coincide with Cellular Rearrangements during Blood Vessel Pruning in Zebrafish Embryos

After the initial formation of a highly branched vascular plexus, blood vessel pruning generates a hierarchically structured network with improved flow characteristics. We report here on the cellular events that occur during the pruning of a defined blood vessel in the eye of developing zebrafish embryos. Time-lapse imaging reveals that the connection of a new blood vessel sprout with a previously perfused multicellular endothelial tube leads to the formation of a branched, Y-shaped structure. Subsequently, endothelial cells in parts of the previously perfused branch rearrange from a multicellular into a unicellular tube, followed by blood vessel detachment. This process is accompanied by endothelial cell death. Finally, we show that differences in blood flow between neighboring vessels are important for the completion of the pruning process. Our data suggest that flow induced changes in tubular architecture ensure proper blood vessel pruning.     

A Fall in Blood Glucose Level Precedes Meal Onset in Free-Feeding Rats

LOUIS-SYLVESTRE, J. AND J. LE MAGNEN. Chez les rats se nourrissant librement, une chute de glycémie précède chaque repas. NEUROSCI. BIOBEHAV. REV. Suppl. 1, 13–15, 1980 - L'hypothèse selon laquelle la stimulation à manger ou éveil spécifique de faim a pur origine une chute de glucèmie induite par le déficit périodique entre production hépatique et utilisation périphérique du glucose est ancienne. Cependant, jusqu'a present, les résultats de déterminations épisodiques de la glycémie, pratiquées au cours des intervalles interprandiaux, chez le rat se nourrissant ad libitum n'ont pas apporte de preuve directe. Une technique permettant une détermination continue, de longue durée, de la glycémie chez le rat se nourrissant librement a été mise au point. Son utilisation a permis de montrer que 5 à 6 minutes avant tout repas, diurne ou nocturne, se produit une chute de glycémie de 6 à 8%.     

Imaging Transient Blood Vessel Fusion Events in Zebrafish by Correlative Volume Electron Microscopy

The study of biological processes has become increasingly reliant on obtaining high-resolution spatial and temporal data through imaging techniques. As researchers demand molecular resolution of cellular events in the context of whole organisms, correlation of non-invasive live-organism imaging with electron microscopy in complex three-dimensional samples becomes critical. The developing blood vessels of vertebrates form a highly complex network which cannot be imaged at high resolution using traditional methods. Here we show that the point of fusion between growing blood vessels of transgenic zebrafish, identified in live confocal microscopy, can subsequently be traced through the structure of the organism using Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) and Serial Block Face/Scanning Electron Microscopy (SBF/SEM). The resulting data give unprecedented microanatomical detail of the zebrafish and, for the first time, allow visualization of the ultrastructure of a time-limited biological event within the context of a whole organism.     

血液循环在大脑信息处理过程中的时序控制作用

自2006年以来,作者已陆续在一些杂志,网站和学术会议[1-3]上发表一些文章和证据,主要探究如下几个问题:(1)讨论各种脑电波现象的起源,大脑信息处理过程,血液循环三者之间关系.(2)提出了血液循环在大脑处理信息的过程中起到了基础时钟的作用;提出其可能的一个分子机制,其中H 浓度,O2浓度,微循环系统的工作机制,NMDA受体的H 位点是几个关键因素.(3)大脑如何感知时间的生理机制.提出时间感(或者时间流逝感)其实是一种压感,来源于当血液流经大脑的血管网的时候,造成的压感;而大脑对连续物理过程的感知则是大脑中记录情景(照片)的一个细胞群序列兴奋的信号和压感通过捆绑效应整合给人的感觉(即有点像放电影).在本文中,将对这些观点和证据进行回顾:文章第1节在整体上叙述所建立的脑电波模型,和血液循环在大脑处理信息上具有时序控制作用的观点.第2～5节将从各方面给出支持第1节中所叙述模型和观点的证据,并对一些问题进行澄清.第6～8节将该模型应用于解释一些脑电波和神经生理现象,解决目前一些问题(例如α波的起源问题,睡眠的脑电现象等).     

“血液循环”一节的教学安排

自课改以来．如何创造性地使用教材,一直是我们的一个研究课题。几年来,围绕“以学生发展为本”的目标,依据生物学课程标准,结合本地、本校的实际情况,大胆突破教材的内容编排,对所使用教材中的部分内容进行了重组、整合,从而解决了教材内容与学习时间、活动内容与活动场地等的矛盾,使课堂教学更加贴近实际,让学生在愉悦的学习氛围中主动获取新知。     

Alterations in Electrolyte and Trace-Element Concentrations During Simulated Extracorporeal Blood Circulation

In our studies with simulated extracorporeal blood circulation we observe damaging effects on blood cells, especially under oxygenating conditions. In order to characterize these effects we also analysed electrolyte and trace-element concentrations in plasma during and after simulated extracorporeal blood circulation. Highest resorption effects for magnesium and highest desorption effects for calcium, copper and iron are found with oxygen gas flow in the system. Membrane permeability for electrolytes seems to be induced as well. Cellular damage due only to mechanical stress within the perfusion system can be neglected.     

血循毒蛇咬伤肌酸激酶干预研究

目的观察甘露醇对血循毒蛇咬伤患者肌酸激酶(CK)值的影响,降低和预防横纹肌溶解症及骨筋膜室综合征的发生率。方法将我院2009~2013年血循毒蛇咬伤住院患者104例随机分成两组,A组(观察组)患者入院后3h内开始使用甘露醇125~250ml每12h1次输注作CK预处理;B组(对照组)未使用甘露醇。观察比较两组CK值差异、横纹肌溶解症及骨筋膜室综合征发生率、平均住院天数。结果 A组CK值水平明显低于B组(P0.05);横纹肌溶解症发生率为5%、骨筋膜室综合征发生率为0%、平均住院天数为4.78天,明显低于B组的20.45%、4.55%和6.89天,差异有统计学意义。结论使用甘露醇对CK干预是减少及预防血循毒蛇咬伤后横纹肌溶解症及骨筋膜室综合征的有效措施,对血循毒蛇咬伤无明显禁忌证的患者甘露醇可以常规使用。     

Thermoregulation and Blood Circulation in Adults during Short-Term Exposure to Extreme Temperatures

Two groups of male and female subjects aged 36–50 years were examined prior to and after short-term exposure to extreme temperatures. One group was exposed to heating in a sauna, and the other was exposed to cooling in ice-cold water. In both cases, the changes in some indices of thermoregulation and blood circulation approximated critical values. It is therefore concluded that, in adults, such procedures are stressful and dangerous for health.     

Evaluation of the Blood Circulation System in Pilots of Deck Aircrafts during Long-distance Missions

The goal of this study was to evaluate the state of cardiovascular system in fighter and helicopter pilots during a long-distance naval mission. The study was carried out aboard a heavy aircraft carrier in pilots of deck aircrafts, and its participants were represented by 17 fighter pilots, 9 helicopter pilots, as well as 21 flight operations controllers. The circulation indicators were studied by the method of volumetric compression oscillography, using an APKO-8 oscillometric analyzer of circulation. An AnnaFlash 2000 digital 24-h ECG accumulator was used to monitor the time course of heart rate (HR) in fighter and helicopter pilots flying off the deck of the carrier. The analysis of the central and peripheral hemodynamic indicators has shown a significant predominance of pilots with prehypertension and mild hypertension among the flight personnel of deck-based aviation. Maximal values of systolic, diastolic, and mean blood pressure prevailed in helicopter pilots, while minimal values were characteristic of fighter pilots. Differences in these parameters between helicopter and fighter pilots tended to increase gradually with the duration of the long-distance mission. Maximum HR increases (up to 157 bpm) were recorded in fighter pilots during landing on the carrier deck). The most stressful task for helicopter pilots proved to be the descent of a rescuer in a winch, which was evidenced by the HR values increasing up to 132 bpm. The indicators of adaptation to the conditions of a naval mission varied within wide ranges. Fighter pilots adapted themselves more successfully than helicopter pilots. Hence the conclusion about the necessity to upgrade the system of flight personnel selection and training for operating under the conditions of a long-distance naval mission, as well as the monitoring of the health state of pilots.     

Pyruvate Kinase M2 in Blood Circulation Facilitates Tumor Growth by Promoting Angiogenesis

It is long known that pyruvate kinase isoform M2 (PKM2) is released into the circulation of cancer patients. The PKM2 levels in patients have been suggested as a diagnostic marker for many types of cancers. However, it is not known how PKM2 is released in the blood, and whether the circulating PKM2 has any physiological function(s) in tumor progression. In this report, we demonstrate that PKM2 in the blood facilitates tumor growth by promoting tumor angiogenesis. Our experiments show that PKM2 promotes tumor angiogenesis by increasing endothelial cell proliferation, migration, and cell-ECM adhesion. Only the dimeric PKM2 possess the activity in promoting tumor angiogenesis, which is consistent with the observations that PKM2 in circulation of cancer patients is a dimer form.