类器官的应用研究进展

类器官是利用干细胞的自我更新和分化能力,在体外培养形成的一种微小组织器官类似物,在很大程度上具有体内相应器官的功能。迄今为止,在3D培养条件下,已经成功培养出多种类器官如肺、胃、肠、肝和肾等类器官。它们不仅可作为组织器官的替代品用于药物和临床研究,还可用于体内器官移植。本文综述了类器官在药物毒性检测、药效评价和新药筛选中的作用以及利用类器官建立疾病模型、研究组织器官发育和类器官在精准医疗、再生医学中的价值。     

果蝇变态过程中的细胞凋亡和细胞自噬

程序化细胞死亡(programmed cell death,PCD)分为I型PCD细胞凋亡(apoptosis)和II型PCD细胞自噬(autophagy)。果蝇等完全变态昆虫有2种类型的器官:即细胞内分裂器官(如脂肪体、表皮、唾液腺、中肠、马氏管等)和有丝分裂器官(复眼、翅膀、足、神经系统等)。在昆虫变态过程中,细胞内分裂器官进行器官重建,幼虫器官大量发生细胞凋亡和细胞自噬到最后完全消亡,同时成虫器官由干细胞从新生成;而有丝分裂器官则由幼虫器官直接发育为成虫器官。在果蝇等昆虫的变态过程中,细胞凋亡和细胞自噬在幼虫器官的死亡和成虫器官的生成中发挥了非常重要的作用。文章简要介绍细胞凋亡和细胞自噬在果蝇变态过程中的生理功能和分子调控机制。     

消化系统类器官研究进展

类器官是一种近年来新发展的细胞三维培养系统。类器官与真实器官的三维结构相似,并具有自我更新和再现组织来源等特点,从而能够更好地模拟真实器官的功能。类器官为研究器官发生、再生、疾病发病机制以及药物筛选提供了一个崭新的研究和应用平台。消化系统在人体内发挥着重要功能,目前已成功建立多种消化器官的类器官模型。本文就近年来味蕾、食管、胃、肝和小肠类器官的研究进展及相关应用进行综述,并对这几种类器官的应用前景进行展望。     

胰腺类器官技术的发展及应用

在人类生物学和疾病的研究过程中,动物模型扮演了重要的角色。但随着研究的深入,其局限性也逐渐凸显。新兴的人类类器官(organoid)技术较好地弥补了动物模型的不足。类器官主要是指由干细胞衍生出的3D多细胞微器官。它能在体外模拟组织器官自发的谱系分化与稳态维持,并具备类似于体内组织器官的生理功能。目前,类器官培养技术在很多器官(比如胃肠道、食管、肝、胆、脑和膀胱等)中都取得了较好的进展。胰腺是人体内唯一的一个既是外分泌腺又是内分泌腺的特殊脏器。因此,胰腺类器官技术的发展面临更大的挑战。目前,胰腺导管类器官和胰岛类器官技术日渐优化,但如何构建复合型胰腺类器官仍是当前研究的难点。该综述将主要回顾胰腺的发育过程、体外定向分化技术以及胰腺类器官模型构建与应用等最新研究成果,同时简要探讨胰腺类器官模型具有潜力的发展方向。     

1例腹腔多器官联合移植术后的观察与护理

器官移植包括器官移植（1个器官）、联合器官移植（2个器官）和多器官联合移植（3个器官及以上）。腹部多器官联合移植（AMOT）牵涉的器官多而复杂,手术创面大,失血多,风险高,术后易出现并发症、排异和感染等风险。随着近年来外科手术学、移植免疫学、新的免疫抑制剂和器官保存技术的进展,我国的器官移植水平已得到迅速的发展。现对我院收治1例行多器官联合移植的重症患者术后的观察和护理报告如下。     

器官移植的伦理问题

器官移植分为自体移植和异体移植,自体移植较少伦理方面的问题,如烧伤病人自体皮肤的移植等;异体移植涉及到器官的来源问题,情况往往变得很复杂。异体器官只谈来源人体的器官,不涉及其它物种来源的器官。过去较为成功的是从双胞胎具有双个的器官（如肾）、再生器官（如骨髓）,但大量的器官可能来自于尸体或其它来源,因此这方面的伦理问题最多。     

小型猪在异种移植中的应用前景

很早以前,人们就认识到,人体健康或生命之所以不能维持,往往不是机体所有器官受到损害,而是由于部分组织或个别生命重要器官丧失功能所致,因而产生了更换受损组织或器官的设想。为了实现用新的器官替换功能低下器官的愿望,19世纪的欧洲即已开始尝试器官移植的相关实验研究。然而,人源供体器官异常短缺,许多患者在等待器官的过程中死亡,这使人们将目光转向了异种移植,     

类器官芯片

类器官芯片是一种新兴前沿交叉技术,它通过整合类器官与器官芯片,可在体外构筑具有高度生理关联性的器官模型系统,在组织器官发育、疾病研究、药物筛选和再生医学等领域具有重要的应用潜力.本文概述了类器官芯片的产生、技术特点及研究进展,并对其未来发展和面临的挑战进行了展望.     

自愿捐赠移植器官的知情同意权问题的探讨

自从人体器官移植技术开展以来，器官捐赠已经成为器官来源的最重要的途径和方式。随着该项技术的广泛开展，规范了器官捐赠行为，使器官捐赠者的自主权得到有效合法保护，捐赠者的知情权和同意权得到全面履行，从而提高捐赠者参与社会捐赠的积极性，以便解决器官需求紧缺状况。     

类器官在再生医学中的应用

类器官是干细胞在体外基质材料支撑条件下培养出来的一种三维微器官,与来源组织器官高度相似。类器官技术为基础研究、药物筛选、再生医学等领域提供了一个新的强大的研究模型和技术手段。再生医学的目的是帮助组织或器官恢复其正常的生理功能,通过与组织工程或基因工程相结合,类器官为再生医学提供了新的移植物来源。该文将介绍类器官在再生医学中的应用,并讨论该领域发展过程中所面临的主要挑战。     

Sink-limitation and the size-number trade-off of organs: production of organs using a fixed amount of reserves

To analyze the nature of size-number trade-off of organs, we develop models in which the effects of sink-limitation in the growth of organs and the loss of resources by maintenance respiration are taken into consideration. In these models, the resource absorption rate of an organ is proportional to either its absolute size or its surface area and either the initial size of an organ or the total initial size of the organs produced is fixed. In all models, organs are produced using a fixed amount of reserved resources and no additional resources become newly available for their growth. We theoretically show that size-number trade-offs are nonlinear if the resource absorption rate of an organ is proportional to the absolute size of the organ and the initial size of the individual organs is fixed or if the resource absorption rate of an organ is proportional to the surface area of the organ. In these nonlinear size-number trade-offs, the size of individual organs increases less rapidly than in linear trade-offs with a decrease in the number of organs and the total size of organs is an increasing function of the number of organs produced. This implies that increasing the number of organs produced is advantageous in terms of resource-use efficiency. In contrast, size-number trade-off is linear if the resource absorption rate of an organ is proportional to the absolute size of the organ and there is a linear trade-off between the initial size of organs and their number. To exemplify the effects of those size-number trade-offs on the life-history evolution, we calculate the optimal offspring sizes that maximize the number of offspring successfully being established. In the case of nonlinear size-number trade-offs, the optimal offspring sizes are smaller than the optimal offspring size in the case of linear size-number trade-offs, namely, that in the model of Smith and Fretwell (1974). Our optimal offspring size depends on the metabolism of organ development; the optimal offspring size decreases with an increase in maintenance respiration rate relative to the growth coefficient of organs.     

甜樱桃对15N尿素的吸收、分配和利用特性

以5年生‘早大果’甜樱桃为试材, 研究了其在萌芽前土施¹⁵N尿素的吸收、分配和利用特性.结果表明：植株器官从肥料中吸收分配到的¹⁵N量对该器官全氮量的贡献率(Ndff)均随时间推移逐渐升高, 盛花期细根和贮藏器官的Ndff较高; 果实硬核期,新生器官中长梢和长梢叶的Ndff增长迅速,分别达0.72%和0.59%; 果实硬核期到采收期,果实的Ndff增长迅速,到采收期达到最高,为1.78%; 果实采收后到花芽分化期,新生器官Ndff增长减慢而贮藏器官增长迅速.盛花期根系吸收的氮素首先分配到贮藏器官,粗根¹⁵N分配率最高,为54.91%;果实硬核期细根和贮藏器官¹⁵N分配率由盛花期的85.43%下降到55.11%,而地上部新生器官则升高至44.89%;果实采收期¹⁵N分配率变化不大,果实采收后氮素营养迅速向贮藏器官中运转,花芽分化期细根和贮藏器官的¹⁵N分配率升高至72.26%,而地上部新生器官¹⁵N分配率与采收期相比下降了19.31%.从盛花期到花芽分化期,植株对¹⁵N尿素的当季利用率呈升高趋势,于花芽分化期达到最高,为16.86%.     

不同供水条件下冬小麦叶与非叶绿色 器官光合日变化特征

为揭示小麦叶片与非叶绿色器官的光合活性在一日中的变化特性及其在器官间的差异性,探讨群体及不同器官光合日变化对不同供水条件的响应特征,在田间设置生育期不灌水(I0)、灌2水(I2,拔节水＋开花水)和灌4水(I4,起身水+孕穗水+开花水+灌浆水)3个处理,于灌浆期测定了群体光合与呼吸速率的日变化, 旗叶片、叶鞘、穗、穗下节间各器官光合速率、蒸腾速率、气孔导度及叶绿素荧光参数的日变化。结果表明,灌浆期小麦穗和穗下节间光合速率日变化呈单峰曲线,而旗叶叶片与旗叶鞘光合速率均呈双峰型,表现出不同程度的午休。随着灌水次数减少,各器官光合速率降低,叶片对严重水分亏缺的反应大于各非叶器官。器官光合速率的日变化与F_v/F_m变化相一致,而与气孔导度日变化有较大差异。各器官上午的累积光合量均高于下午,上午光合量占日总光合量的比例为51％-62％,随着灌水次数减少而增大。不同灌水处理群体光合速率、呼吸速率日变化均未出现午休现象。春季浇2水处理与春浇4水处理相比,灌浆期群体光合速率及日光合积累量没有显著差异。综合研究认为,小麦叶与非叶器官光合性能及其日变化特征有较大不同,非叶光合对水分亏缺的敏感性低于叶片,生育期浇2水可以获得与浇4水相似的群体日光合积累量。     

The coordination of growth among Drosophila organs in response to localized growth-perturbation

The developmental mechanisms by which growth is coordinated among developing organs are largely unknown and yet are essential to generate a correctly proportioned adult. In particular, such coordinating mechanisms must be able to accommodate perturbations in the growth of individual organs caused by environmental or developmental stress. By autonomously slowing the growth of the developing wing discs within Drosophila larvae, we show that growing organs are able to signal localized growth perturbation to the other organs in the body and slow their growth also. Growth rate is so tightly coordinated among organs that they all show approximately the same reduction in growth rate as the developing wings, thereby maintaining their correct size relationship relative to one another throughout development. Further, we show that the systemic growth effects of localized growth-perturbation are mediated by ecdysone. Application of ecdysone to larvae with growth-perturbed wing discs rescues the growth rate of other organs in the body, indicating that ecdysone is limiting for their growth, and disrupts the coordination of their growth with growth of the wing discs. Collectively our data demonstrate the existence of a novel growth-coordinating mechanism in Drosophila that synchronizes growth among organs in response to localized growth perturbation.     

广东南亚热带马占相思林呼吸量的测定

 采用红外CO2分析仪离体测定了鹤山丘陵马占相思(Acacia mangium)的树干、树枝、树叶和树根等器官的呼吸速率,根据管道模型理论(Pipe model theory),测出马占相思各木质器官直径频度分布的函数表达式、呼吸速率与直径的幂函数关系表达式和林木各器官呼吸量的表达式。结果表明：各木质器官的呼吸速率与直径呈负相关,林木各器官的呼吸量则与胸径和树高(D2H)呈正相关;马占相思林的年总呼吸量(乔木层)为47.51 tCO2·hm-2, 其中树干、树枝、树叶、树根分别占总量的23.1％、13.9％、48.7％和14.4％,树叶占总量的近一半。     

迁徙鸟类中途停歇期的生理生态学研究

大多数候鸟的迁徙活动由迁徙飞行和中途停歇两个部分组成。在迁徙过程中,鸟类要多次交替经历消耗能量的飞行阶段和积累能量的中途停歇阶段。从鸟类在中途停歇时期的能量积累速度、体重变化模式以及迁徙飞行中的禁食或食物限制、食物种类的改变、中途停歇的能量快速积累过程对消化器官的影响等方面,对目前迁徙鸟类的生理生态学研究成果进行回顾,并提出有待解决的问题及今后的研究方向。     

Target organ and time-course in the mutagenicity of five carcinogens in MutaMouse: a summary report of the second collaborative study of the transgenic mouse mutation assay by JEMS/MMS.

We studied five carcinogens for (a) organ-specific mutagenicity and expression time in the transgenic (TG) mouse mutation assay and (b) clastogenicity in the peripheral blood micronucleus assay in the same mice. Groups of mice were injected intraperitoneally (ip) with N-nitroso-di-n-propylamine (NDPA), propylnitrosourea (PNU), 7, 12-dimethylbenz[a]anthracene (DMBA), 4-nitroquinoline-1-oxide (4NQO), or procarbazine (PCZ); 4NQO was also administered orally. LacZ mutant frequencies (MF) of various organs, sampled 7, 14 and 28 days after treatment, were analyzed by galE positive selection. At least 5 organs were analyzed in each experiment. Bone marrow, liver, and testis were always analyzed, as were each chemical's target organs. All chemicals, except NDPA, induced micronuclei. All chemicals increased lacZ MF in all of their target organs for carcinogenesis and, to a lesser extent, in some non-target organs. That suggests that an organ that has a positive response to a chemical in the TG mouse mutation assay is likely to develop tumors on exposure to that chemical, but it does not always happen. The time-course of MF increases (7-28 days) differed among tissues. In general, time-dependent increase in MF occurred in organs with a low cell proliferation rate whereas no increase, or even a decrease, occurred in organs with a high proliferation rate. Our results demonstrated that the TG mouse mutation assay is effective for the detection of chemical mutagenesis in the target organs for carcinogenesis, and organ and time-course variations in chemical mutagenesis are important issues for the establishment of an optimal protocol for the assay.     

Rôle des organes pulsatiles thoraciques et du cœur pendant l'émergence et l'expansion des ailes des lépidoptères

Electrograms of the thoracic pulsatile organs and of the heart during emergence and expansion of the wings have been made. The mesotergal and metatergal organs function in a similar way: active periods are interrupted by short periods of rest, but the two organs contract with different but apparently independent rhythms. During emergence and expansion, the rate of contraction of the pulsatile organs increases twofold, and the resting periods disappear during the entire period of expansion of the wings. When the wings are removed or cut short, the activity of the pulsatile organs is inhibited.     

Growth Analysis and Reproductive Allocation of Japanese Forbs and Grasses in Relation to Organ Toughness under Trampling

Abstract: The growth and reproduction of Japanese forbs ( Artemisia princeps and Piantago asiatica ) and grasses ( Digitaria ad-scendens and Eleusine indica ) treated to 25 tramplings (3 g m^-2) per week were investigated in relation to the toughness (tensile strength) of organs. The perennial erect forb, A. princeps , was the most sensitive to trampling in terms of a remarkable depression of plant size and relative growth rate (RGR). RGR and net assimilation rate (NAR) of trampled A. princeps were negative. This was promoted by a loss of organs due to a reduced toughness of organs following trampling. In contrast to this species which did not flower after trampling, the perennial rosette forb, P. asiatica , maintained its plant biomass, NAR, RGR and reproduction under trampling because of tougher organs. However, NAR without trampling was lower in P. asiatica due to a larger leaf dry mass per leaf area (LMA), which could contribute to leaf toughness under trampling. The annual tussock grass, D. adscendens , which has a greater RGR than that of another grass, E. indica , without trampling was intolerant to trampling in terms of decreased biomass and RGR under trampling due to more sensitive organs, although it maintained an ability to reproduce. On the other hand, E. indica showed a marked trampling tolerance, with hardly reduced plant biomass and RGR. This species showed increased toughness of organs when trampled and frequently formed inflorescences in the growing period and produced similar biomass allocation to reproductive organs to untrarnpled plants. Between the grasses, RGR without trampling was slower in E. indica , partly because of its larger LMA. These results suggest that plants face a dilemma between trampling tolerance and efficient assimilative capacity and/or growth rate.     

Chemical and molecular exchange effects on T2 relaxation of living tissues: a pulse spacing dependence study

Contrast in magnetic resonance imaging depends principally on the longitudinal relaxation (R1) and the transverse relaxation rate (R2) of the observed nuclei, most often the protons. The spin-spin relaxation rate (R2) is the result of several mechanisms. The dependence of the interpulse delay of the Carr-Purcell-Meiboom-Gill sequence on the transverse relaxation rate of the water was studied in rat organs in vitro. It gives an insight into the exchange mechanisms involved. The increase of the interpulse delay from 0.2 ms to 5 ms gives an R2 increase of 23, 15, 3, and 2 s-1 for the heart, the liver, the spleen and the brain, respectively. These increases are compared to the R2 increases obtained in 17O-enriched water, amino acid and albumin solutions atomic exchange takes place. The concentration of these materials in organs cannot explain the R2 increase of the organs with the interpulse delay. Water exchange between intra and extracellular compartments is proposed to explain the R2 increase with interpulse delays in organs like the heart and the liver.