空气流动增加压力型整体体积描记箱内压力变化的空气动力学研究

动物实验中,计算小动物呼吸容量如潮气量时通常遵循Boyle定律。而小动物在压力型体积描记箱内呼吸时,箱内气体处于不停的流动状态。为了研究气体流动本身对描记箱内压力是否产生影响,本研究采用空气动力学理论推导出压力型体积描记箱内压力变化的近似公式,并设计了三个实验对理论公式进行证明。首先,往体积描记箱内注入0.1mL、0.2mL和0.4mL空气,结果显示,描记箱内压力迅速上升至一峰值然后下降为一水平的基线压力值。3种容量的空气注入产生的压力变化最大值(峰压)及压力保持平稳时的压力变化值(基线压)分别为:(0.828±0.004)cmH2O、(0.684±0.003)cmH2O;(1.650±0.010)cmH2O、(1.350±0.007)cmH2O;(3.280±0.014)cmH2O、(2.658±0.011)cmH2O,峰压均显著高于基线压。其次,往体积描记箱内注入相同容量、但通气频率不同的空气,结果显示,随着注入空气的频率增加,描记箱内压力变化幅度亦显著增加。最后,用小动物呼吸机和微量移液器分别往描记箱内注入相同容量、相同频率但流量-时间函数不同的气体,结果显示,呼吸机引起的体积描记箱内峰压及基线压均显著高于微量移液器。以上结果表明,空气流动本身在压力型体积描记箱内引起压力变化;空气流动越快,压力变化幅度也越大;流动空气的流量是时间的不同函数时,压力变化也将显著不同。因此要精确地计算小动物呼吸容量变化,需要使用更多的空气动力学原理。     

小鼠腹腔水液体积检测方法建立及肾阳虚模型小鼠水负荷的评价

目的 建立小鼠腹腔水液体积的检测方法并评价肾阳虚模型小鼠的水负荷状况.方法选取正常小鼠12 只,根据＂阿基米德原理＂改进实验方法测量小鼠的腹腔水液体积,对其腹腔水液体积测量的稳定性进行评价;选取正常小鼠5 只,利用小鼠腹腔水液检测方法对其进行线性关系考察;将SPF 级昆明种雄性小鼠30 只,随机分为正常组和肾阳虚模型组,肾阳虚模型组上午按0.08 mg/10 g 腹腔注射苯甲酸雌二醇注射,正常组腹腔注射相同剂量的大豆油,下午两组均腹腔注射1 mL 的生理盐水造成水负荷,连续15 d.结果该测量方法的稳定性和线性关系考察均取得了良好的效果;与正常组相比,造模后体重显著性降低（P ＜0.01）,肛温显著性降低（P ＜0.01）,趾温差异无显著性（P ＞0.05）;自主活动明显减少（P ＜0.05）;游泳时间明显降低（P ＜0.01）,综合评价说明肾阳虚造模成功;肾阳虚模型组的腹腔水液测量体积整体表现出下降的趋势,腹水指数显著高于正常组（P ＜0.05）.结论该检测方法可以快速、准确的测量出小鼠腹腔水液测量体积和腹水指数的变化,可以能较客观地评价中医证候的特点,为中医证候症状描述进一步提供实验数据支持.     

气雾攻击法感染结核病小鼠模型的建立及其综合评价

目的 模拟自然感染方式建立结核病小鼠模型,并对其病理变化进行综合评价.方法 通过气雾攻击方式将结核分枝杆菌H37Rv接种至C57BL/6J小鼠体内.在感染后的4周、6周、8周对小鼠进行micro-CT活体动态扫描,无菌分离肺脏和脾脏,肉眼观察病变情况,活菌菌落计数,组织病理检测(HE和抗酸染色).结果 肉眼观察和micro-CT扫描发现,不同时间小鼠肺部感染情况逐渐加重,至感染后第8周时病变弥漫至整个肺部;HE染色肺组织出现弥漫性肉芽肿样实变;抗酸染色可见结核分枝杆菌.结论 通过大体病变、病理、影像、菌落计数几个方面对建立的小鼠模型进行综合分析,证明利用气雾攻击法感染的结核病小鼠模型建立成功;该模型在形成病变时与结核患者的情况存在一定差异,对其完善的综合评价有助于在相关研究中对该小鼠模型的合理应用.     

小鼠的非手术法采精

用徒手法、假阴道抽吸法和电刺激法进行小鼠非手术法采精探索 ,结果表明 :假阴道抽吸法和电刺激法可采出精子 ,两者采精成功率、平均精子量和精子活率均差异不显著 ;小鼠不同射精阶段的精子含量不同 ,其中精子主要集中在射精的第二阶段和第三阶段 ;假阴道抽吸法和电刺激法对小鼠首次采精后 ,用同样的方法对相应的小鼠重复采精 ,成功率、平均精子量和精子活率与首次采精相比差异均不显著     

小鼠卵巢组织的超速冻存法研究

目的　本实验通过对小鼠卵巢组织进行冻存研究 ,掌握卵巢的低温生物学特性 ,摸索出一种简便有效的组织器官冻存法 ,为卵巢移植及器官冷冻提供有用的技术方法。方法　通过对小鼠卵巢组织进行慢速程序法与快速液氮蒸汽法冻存 ,比较分析了不同方法所需保护剂种类、浓度、渗透平衡时间。采用对解冻后卵巢组织超微结构观察、组织化学染色、激素测定及自体、异体移植后动情期的恢复作为评价指标。结果与结论　通过上述实验表明用同种冷冻保护剂 ,液氮蒸汽法冻存的卵巢组织超微结构保存良好 ;组织化学染色示其活性与程序法冻存组织相同 ;自体、异体移植后 ,小鼠动情周期的恢复率及血清雌二醇水平各项指标均与慢速程序法冷冻无显著性差异     

TUNEL法检测乳酸杆菌对小鼠宫颈鳞癌的凋亡诱导作用

目的应用脱氧核苷酸转移酶介导的dUTP缺口末端标记法———TUNEL法,检测乳酸杆菌(Lactoba-cillus,LB)对小鼠宫颈鳞癌的凋亡诱导作用。方法建立615近交系小鼠U14移植瘤动物模型,并随机分组,TUNEL法检测各组细胞凋亡指数(apoptosis index,AI)。结果乳酸杆菌实验组的AI为(11.25±4.06)%,与对照组的差异有非常显著性(P<0.01),与抗癌药顺铂组的差异有显著性(P<0.05)。结论乳酸杆菌可诱导U14移植瘤细胞凋亡,这可能是其抑癌机制之一。     

家蚕核型多角体病毒对小鼠的易感性及其蛋白组份的检测

家蚕核型多角体病毒(Bm-NPV)是一类环状DNA病毒。该病毒作为载体,应用在杆状病毒-昆虫真核生物表达系统。为确定家蚕基因工程表达系统产品对人的安全性,观察了该病毒对哺乳动物细胞株及对小鼠的易感性,建立了检测Bm-NPV蛋白组份的dot-ELISA方法,可用于生物表达器生产的产品中残存多角体病毒组份的检测。结果表明,芽生型多角体病毒(BV)在杂交瘤细胞和HL60细胞中不增殖。不同剂量包埋型多角体病毒(OV)灌胃感染小鼠,小鼠肝、肾组织切片的电镜观察及免疫组化染色未见到病毒颗粒。     

银染DD-PCR法筛选游泳疲劳小鼠肝脏中差异表达基因的初步研究

目的:筛选小鼠游泳疲劳相关基因,为阐明疲劳产生的分子机制奠定基础.方法:取30只BALB/c雄性小鼠,体重(20±2)g,随机分成对照组、浸水组和游泳疲劳组,对游泳疲劳组小鼠进行负重游泳致疲劳后,与其他两组同时采集肝脏组织,利用改进后的银染DD-PCR法筛选小鼠肝脏中差异表达的基因,并进行鉴定,采用BLAST软件对阳性片段进行同源性分析.结果:经反向Northern blot和测序鉴定后,获得了7条阳性差异表达基因片段(DD-ESTs),其中有2条DD-ESTs只在游泳疲劳组表达,2条呈现下调表达,另3条呈现上调表达;阳性片段中一条为新基因,登录GenBank数据库后获得登录号为AY615302.结论:利用银染DD-PCR法获得了7条游泳疲劳小鼠差异表达基因片段(DD-ESTs).     

白花蛇舌草提取物对乳腺癌荷瘤小鼠干预作用的实验研究

目的:明确白花蛇舌草提取物对乳腺癌荷瘤小鼠肿瘤发生发展的干预作用及可能机制,以期为其未来的临床应用提供实验依据。方法:选择12周龄的雄性BALB/c小鼠30只,随机等分成3组:对照组(Control)、乳腺癌荷瘤小鼠组(BC)和乳腺癌荷瘤小鼠行白花蛇舌草药物治疗组(BC+HD)。BC组和BC+HD组小鼠的右侧肩胛骨注射以0.2 m L的MCF-7乳腺癌细胞悬液(细胞浓度为2×10~7/m L),Control组小鼠注射等量的生理盐水。在2周后,对BC+HD组小鼠进行白花蛇舌草的灌胃给药,BC组和Control组小鼠灌以等量的生理盐水。在给药的第21天后,处死全部小鼠,分析小鼠的体重、总摄食量、肿瘤重量和肿瘤体积,使用酶联免疫吸附测定(enzyme linked immunosorbent assay,ELISA)法定量分析小鼠血清中的白介素-6(interleukelin-6,IL-6)和血管内皮生长因子(vascular endothelial growth factor,VEGF)的含量。结果:给药21天后,BC+HD组小鼠体重显著高于BC组(P0.05),总摄食量、肿瘤重量、肿瘤体积、血清IL-6和VEGF的含量均显著低于BC组(P0.05)。结论:白花蛇舌草能够有效改善乳腺癌荷瘤小鼠的营养状况,抑制乳腺癌的发生和发展,可能与其有效降低乳腺荷瘤小鼠血清IL-6和VEGF的含量有关。     

Blood volume measurement in baboons: simultaneous estimation of red cell volume and plasma volume

A method is described for frequent sequential blood volume estimation in baboons using 32P for red cell volume measurements and 125I-albumin for simultaneous plasma volume measurements. Values for red cell, plasma, and total blood volumes are reported. Close correlations of the volumes to bodyweight were demonstrated. Circulatory half-lives of the isotopes, determined from disappearance curves, confirmed their suitability for serial measurements in these baboons.     

The measurement of volume change by capillary dilatometry

Capillary dilatometry enables direct measurement of changes in volume, an extensive thermodynamic property. The results provide insight into the changes in hydration that occur upon protein folding, ligand binding, and the interactions of proteins with nucleic acids and other cellular components. Often the entropy change arising from release of hydrating solvent provides the main driving force of a binding reaction. For technical reasons, though, capillary dilatometry has not been as widely used in protein biochemistry and biophysics as other methods such as calorimetry. Described here are simple apparatus and simple methods, which bring the technique within the capacity of any laboratory. Even very simple results are shown to have implications for macromolecular‐based phenomena. Protein examples are described.     

Evaluation of phase correction and low gas density to improve thoracic gas volume measurement

We investigated two methods of decreasing the error on plethysmographic determinations of thoracic gas volume (TGV) related to cheeks movements during panting maneuvers: lowering gas density in the airways with an 80% He-20% O2 mixture and computing TGV from the in-phase component of the plethysmographic signal (TGVr). The methods were tested by measuring how TGV estimates varied when panting frequency was raised from 0.8 to 2.5 Hz during the same occlusion. The measurements were performed in 6 normal subjects and 12 patients with chronic bronchitis with and without cheeks support and when the airway was connected to an external device simulating an increased cheeks compliance. A small negative frequency dependence of TGV (delta TGV/delta f = -1.2 +/- 0.8%/Hz with cheeks support), most probably unrelated to upper airway walls, was found in normal subjects. Delta TGV/delta f was positive and algebraically larger in patients than in normals, reaching 2.2 +/- 3.4%/Hz without cheeks support and 11.8 +/- 8.0%/Hz with the additional cheeks. The latter value was only 20% smaller when computed on the basis of TGVr, demonstrating the limited usefulness of the phase-based correction. In contrast, breathing He-O2 decreased delta TGV/delta f to approximately 50% of its air value (P less than 0.01) and appears as an effective way to diminish the error in obstructive patients.     

Enhanced protection against lipopolysaccharide‐induced acute lung injury by autologous transplantation of adipose‐derived stromal cells combined with low tidal volume ventilation in rats

Adipose‐derived stromal cells (ADSCs) showed excellent capacity in regeneration and tissue protection. Low tidal volume ventilation (LVT) strategy demonstrates a therapeutic benefit on the treatment of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). This study, therefore, aimed to undertaken determine whether the combined LVT and ADSCs treatment exerts additional protection against lipopolysaccharide (LPS)‐induced ALI in rats. The animals were randomized into seven groups: Group I (control), Group II (instillation of LPS at 10 mg/kg intratracheally), Group III (LPS+LVT 6 ml/kg), Group IV (LPS+intravenous autologous 5 × 10⁶ ADSCs which were pretreated with a scrambled small interfering RNA [siRNA] of keratinocyte growth factor [KGF] negative control), Group V (LPS+ADSCs which were pretreated with a scrambled siRNA of KGF, Group VI (LPS+LVT and ADSCs as in the Group IV), and Group VII (LPS+LVT and ADSCs as in the Group V). We found that levels of tumor necrosis factor‐α, transforming growth factor‐β1, and interleukin (IL)‐1β and IL‐6, the proinflammatory cytokines, were remarkably increased in LPS rats. Moreover, the expressions of ENaC, activity of Na, K‐ATPase, and alveolar fluid clearance (AFC) were obviously reduced by LPS‐induced ALI. The rats treated by ADSCs showed improved effects in all these changes of ALI and further enhanced by ADSCs combined with LVT treatment. Importantly, the treatment of ADSCs with siRNA‐mediated knockdown of KGF partially eliminated the therapeutic effects. In conclusion, combined treatment with ADSCs and LVT not only is superior to either ADSCs or LVT therapy alone in the prevention of ALI. Evidence of the beneficial effect may be partly due to improving AFC by paracrine or systemic production of KGF and anti‐inflammatory properties.     

Left ventricular volume measurement in mice by conductance catheter: evaluation and optimization of calibration

The conductance catheter (CC) allows thorough evaluation of cardiac function because it simultaneously provides measurements of pressure and volume. Calibration of the volume signal remains challenging. With different calibration techniques, in vivo left ventricular volumes (V(CC)) were measured in mice (n = 52) with a Millar CC (SPR-839) and compared with MRI-derived volumes (V(MRI)). Significant correlations between V(CC) and V(MRI) [end-diastolic volume (EDV): R(2) = 0.85, P < 0.01; end-systolic volume (ESV): R(2) = 0.88, P < 0.01] were found when injection of hypertonic saline in the pulmonary artery was used to calibrate for parallel conductance and volume conversion was done by individual cylinder calibration. However, a significant underestimation was observed [EDV = -17.3 microl (-22.7 to -11.9 microl); ESV = -8.8 microl (-12.5 to -5.1 microl)]. Intravenous injection of the hypertonic saline bolus was inferior to injection into the pulmonary artery as a calibration method. Calibration with an independent measurement of stroke volume decreased the agreement with V(MRI). Correction for an increase in blood conductivity during the in vivo experiments improved estimation of EDV. The dual-frequency method for estimation of parallel conductance failed to produce V(CC) that correlated with V(MRI). We conclude that selection of the calibration procedure for the CC has significant implications for the accuracy and precision of volume estimation and pressure-volume loop-derived variables like myocardial contractility. Although V(CC) may be underestimated compared with MRI, optimized calibration techniques enable reliable volume estimation with the CC in mice.     

The effects of prolonged emersion and submersion by tidal manipulation on marine macrobenthos

Effects of tidal manipulation, resulting in prolonged periods of emersion and submersion or in protracted tidal cycles, on estuarine benthic animals are reviewed.Prolonged submersion periods did not show effects on mortality of most benthic animals tested, with the exception of the crumb-of-bread sponge Halichondrea panicea, which, at low water-flow rates, was covered with a layer of bacteria and subsequently died.Protracted low-water periods of 18 hours during several weeks hardly caused any mortality. However, protracted low-water periods of 30 hours during some weeks or emersion during several days caused a strong increase in mortality, depending on: the duration of emersion, temperature, condition of the animals, species and age. At temperatures below –1 °C and above 24 °C mortality was generally high. Animals with a low glycogen content were more sensitive to emersion than those with a high content. Species with a shell and those that are relatively big were less sensitive than those without a shell or of small size.The reproductive cycle of benthic animals could be delayed or accelerated by both emersion and submersion.     

Order-preserving dimension reduction procedure for the dominance of two mean curves with application to tidal volume curves

Summary .   The paper here presented was motivated by a case study involving high-dimensional and high-frequency tidal volume traces measured during induced panic attacks. The focus was to develop a procedure to determine the significance of whether a mean curve dominates another one. The key idea of the suggested method relies on preserving the order in mean while reducing the dimension of the data. The observed data matrix is projected onto a set of lower rank matrices with a positive constraint. A multivariate testing procedure is then applied in the lower dimension. We use simulated data to illustrate the statistical properties of the proposed testing procedure. Results on the case study confirm the preliminary hypothesis of the investigators and provide critical support to their overall goal of creating an experimental model of the clinical panic attack in normal subjects.     

Protective role of microRNA-374 against myocardial ischemia-reperfusion injury in mice following thoracic epidural anesthesia by downregulating dystrobrevin alpha-mediated Notch1 axis

Ischemia-reperfusion (I/R) injury often leads to myocardial apoptosis and necrosis. Studies have demonstrated the role microRNAs (miRs) played in myocardial I/R injury. Thus, we established a myocardial I/R injury model and a thoracic epidural anesthesia (TEA) model in mice to explore whether microRNA-374 (miR-374) affects myocardial I/R injury. We collected myocardial tissues to evaluate whether TEA exerts a protection effect on myocardial tissues. In addition, the levels of miR-374, dystrobrevin alpha (DTNA), and the statue of the Notch1 axis were detected. Subsequently, cardiomyocytes extracted from TEA mice were treated to regulate their levels of miR-374 and DTNA. After that, cell viability, cell cycle distribution, and apoptosis of cardiomyocytes were assessed. This was followed by the detection of the myocardial infarction area. The mice models of myocardial I/R injury were associated with poorly expressed miR-374 and highly expressed DTNA. TEA was found to protect myocardial tissues against myocardial I/R injury by elevating miR-374 and reducing DTNA. Dual-luciferase reporter assay validated that DTNA was the target gene of miR-374. Cardiomyocytes with overexpressed miR-374 were shown to have downregulated DTNA levels and blocked Notch1 axis. Overexpressed miR-374 was also found to promote the viability and inhibit the apoptosis of cardiomyocytes, as well as to increase the number of cells arrested in the S phase. In accordance with this, the myocardial infarction area was decreased with the upregulated miR-347 and downregulated DTNA. Collectively, these results demonstrated that, by inhibiting the activity of DTNA-mediated Notch1 axis, miR-374 could protect against myocardial I/R injury in mice after TEA.     

Host volume measurement by the parasitoid wasp Trichogramma minutum: The roles of curvature and surface area

The number of eggs laid into its insect-egg host by Trichogramma minutum Riley (Hymenoptera: Chalcidoidea: Trichogrammatidae) depends on the volume of its lepidopterous host. The wasps allocated fewer progeny into Manduca sexta (L.) (Sphingidae) egg hosts partially embedded in the substrate than into fully exposed hosts, both in daylight and in total darkness. Since the hosts are of identical diameter and surface chemistry, the mechanism of volume determination is neither chemical nor visual, but essentially mechanosensory, based on accessible surface area. Before oviposition, the wasp examines the host surface by walking over it, turning at the edge, and drumming with its antennae. The number of edge turns (N_t) made by wasps when they examined glass beads presented as model hosts was inversely dependent on surface area, but independent of diameter. Conversely, the examination time (T_e) was directly dependent on diameter, but independent of surface area.A mechanism is proposed for host volume measurement. While the wasp examines a potential host, the relative curvature (and hence diameter) is measured, possibly by antennal angle. If this measure is within an acceptable range, the wasp initiates its drumming walk. The measure is also used to set T_c and to establish an estimate of a maximum possible volume (and hence progeny number) to the host object. With T_c fixed, the value for N_t depends on accessible surface area, the wasp turning more often on restricted surfaces. N_t allows the wasp to correct the estimate of host volume such that an appropriate number of eggs is laid in non-spherical hosts. The use of curvature to set T_e increases the accuracy of the wasp's measure of N_t, while also improving its coverage of the surface. The use of curvature and surface area allows Trichogramma to optimize its progeny allocation for a variety of host sizes and shapes.

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Die bestimmung des wirtsvolumen durch die parasitische wespe Trichogramma minutum: Die rolle von krümmung und oberfläche

Zusammenfassung Bei dem Insekten-Eiparasiten Trichogramma minutum (Hymenoptera: Trichogrammatidae) hängt die Anzahl der abgelegten Eier vom Volumen der Wirtseier ab. Es wurden Untersuchungen zur Bestimmung der sensorischen Grundlagen dieses Verhaltens unternommen. Die Wespe weist sowohl im Tageslicht, als auch in totaler Dunkelheit jenen Manduca sexta (L.) (Lepidoptera: Sphingidae) Eiwirten (Diameter c. 1.3 mm) weniger eigene Eier zu, die teils (30%) in Substrat eingebettet sind, als solchen, die ganz herausragen. Da die Wirte einen identischen Radius und gleichen Oberflächengeruch haben, kann der Mechanismus der Volumenbestimmung weder chemisch noch optisch sein, sondern ist dem Wesen nach mechanosensorisch, und von der zugänglichen Oberfläche abhängig. Vor de Eiablage untersucht die Wespe die Wirtsoberfläche, indem sie darüber läuft, an den Ecken umkehrt und mit ihren Antennen trommelt. In Experimenten mit Glaskugelmodellen war die Anzahl der von der Wespe gemachten Wendungen an den Ecken (N_t) umgekehrt proportional zur Oberfläche, aber unabhängig vom Radius. Im Gegensatz dazu, war die Untersuchungszeit (T_e) direkt proportional zum Radius, aber unabhängig von der Oberfläche.Ein Mechanismus für die Volumenmessung wird vorgeschlagen. Gleich beim Besteigen des potentialen Wirtes wird die relative Kurve (und infolgedessen der Radius), wahrscheinlich durch den Antennenwinkel gemessen. Wenn diese Messung innerhalb einer bestimmten Spanne liegt, beginnt die Wespe ihren Trommelgang. Die Messung wird auch dazu benutzt, ein maximales Volumen (und folglich die Anzahl der Nachkommen) des Wirtes und eine maximale Untersuchungzeit (T_e) zu erzielen. Wird T_e konstantgehalten, hängt die Anzahl der Wendungen (N_t) von der zugänglichen Oberfläche ab, wobei die Wespe öfter bei kleineren Oberflächen wendet. Die Anzahl der Wendungen gestattet der Wespe, die ursprüngliche Einschätzung des Wirtsvolumens so zu verändern, daß eine angemessene Anzahl von Eiern in nicht kugelige Wirte gelegt wird. Die Anwendung von kurven-und oberflächenabhängigen Messungen ermöglicht eine optimale Zuweisung von Nachkommen für eine Anzahl von unterschiedlichen Wirtsgrössen und-formen. Die Oberflächenmessung gestattet eine bessere Volumenbestimmung von nicht-kugeligen Objekten. Die gezeigte Abhängigkeit von der Oberfläche ist wahrscheinlich auch eine Anpassung an Wirte, die ihre Eier in Gruppen ablegen. Unter solchen Bedingungen von grosser Wirtsdichte ist es günstiger für die Wespe, weniger Eier in jeden Wirt der Gruppe zu legen, weil diese Verteilung zu grösseren, fruchtbareren Nachkommen führt.