上颌窦的胚胎发育

对46例(92侧)12～40周胎儿标本的上颌窦,行冠状切,HE染色,光镜观察:(1)原始上颌窦在胚胎第20～22周由原始筛漏斗底部扩展而成,上颌窦位于钩突和中鼻道外侧壁的外侧,窦腔与眼眶之间的骨板最薄,且骨化较晚.(2)窦口位于上颌窦的顶部(壁),随胎龄增长,”钩突角”变小.向外下的筛漏斗渐近水平位.(3)出生时,上颌窦大小约3.0×5.0×6.5mm.窦内粘膜上皮细胞呈立方形或矮柱状,其纤毛稀疏,,固有膜增厚、疏松,内含极少量血管和腺体.结果表明:出生时,上颌窦虽已出现,但粘膜厚,窦腔小,且与眼眶的毗邻关系密切,上颌窦粘膜的组织结构与鼻腔粘膜的结构有所不同.     

Selection of stereotyped VH81X-{micro}H chains via pre-B cell receptor early in ontogeny and their conservation in adults by marginal zone B cells

The pre-B cell receptor (preBCR) plays critical roles in early B cell differentiation. It has been shown that not all muH chains are capable of pairing with surrogate light (SL) chains to form preBCR. Here, we established a novel system to differentially identify two types of early pre-B cell populations in bone marrow and fetal liver of mice, one producing SL-pairing muH chains and the other producing SL-non-pairing muH chains. The former population accounted for 80% of all the early pre-B cells in adult bone marrow, while it accounted for only 20% of those in fetal liver. Comparison of the two types of pre-B cell populations in fetal liver revealed the structural difference between SL-pairing and -non-pairing muH chains encoded by the V(H)81X segment that was most frequently utilized in fetal liver pre-B cells but rarely expressed by B cells generated in adults. PreBCR played an important role in the positive selection of V(H)81X-muH chains carrying the characteristic sequences of the complementarity-determining region 3 with little or no nibbling or N nucleotide addition, leading to their predominance in neonatal splenic B cells. These fetal-type V(H)81X-muH chains were also detected in adult spleen, but almost exclusively in marginal zone (MZ) B cells in contrast to the adult-type V(H)81X-muH chains. This strongly suggests that neonatally generated and selected B cells expressing the stereotyped V(H)81X-muH chains are maintained in the adult MZ and could function as innate-like lymphocytes.     

大鼠眼上直肌神经的生后发育

取生后两天、两周和两月的雄性Ｗｉｓｔａｒ大鼠双眼上直肌，进行硝酸银染色和乙酰胆碱酯酶染色，用光镜观察大鼠眼上直肌神经在生后的发育情况。在大鼠生后两天时，动眼神经的分支从眼上直肌的中后三分之一交界处由眶面进入该肌，它向该肌的球面区发出细小的神经纤维束，这些神经束抵达同一条肌纤维上。眶面层神经纤维细小，单条并且平行于肌纤维方向走行。此时，眼上直肌对乙酰胆碱酯酶染色着色浅，反应区未形成某一特定轮廓，说明此时运动神经的发育是不成熟的。在生后两周时，动眼神经的分支开始向眼上直肌的眶面层发出神经纤维；球面区中的神经纤维有明显的粗细两种。这时眼上直肌中的运动神经轴索对乙酰胆碱酯酶染色反应，出现葡萄状运动神经末梢及斑点状运动终板的雏形。生后两月时，眼上直肌中出现了肌梭及典型的葡萄状运动神经末梢和斑点状运动终板。生后两周是大鼠睁眼初期，由此可见，大鼠从闭眼至睁眼的时期，是运动神经发育的关键时期，此时，运动神经形成一些特定神经末梢，而睁眼后运动神经的发育主要在此基础上运动神经末梢日趋完善和成熟。     

A green to red photoconvertible protein as an analyzing tool for early vertebrate development.

Lineage labeling is one of the most important techniques in developmental biology. Most recently, a set of photoactivatable fluorescent proteins originating from marine cnidarians became available. Here, we introduce the application of the green to red photoconvertible protein EosFP as a novel technique to analyze early vertebrate development. Both injection of EosFP mRNA and purified, recombinant EosFP followed by a light-driven green to red conversion allow lineage labeling in virtually any temporal and spatial dimension during embryonic development for at least 2 weeks. Specific staining of cells from nonsurface layers is greatly facilitated by light-driven conversion of EosFP compared with traditional methods. Therefore, green to red photoactivatable proteins promise to be a powerful tool with the potential to satisfy the increasing demand for methods enabling detailed phenotypical analyses after manipulations of morphogenetic events, gene expression, or signal transduction.     

Differences between human and mouse alpha‐fetoprotein expression during early development

Alpha‐fetoprotein (AFP) is the major serum protein during development. AFP is one of the earliest proteins to be synthesised by the embryonic liver. The synthesis of AFP decreases dramatically after birth and only trace amounts are expressed in the adult liver. The tissue distribution of AFP in early human embryogenesis has not been defined. We have studied the expression pattern of AFP mRNA in human and mouse embryos by in situ hybridisation. In humans, AFP is expressed in the hepatic diverticulum at 26 d postovulation as it differentiates from the foregut endoderm (i.e. in the most primitive hepatocytes). It is also expressed in the endoderm of the gastrointestinal tract and in the yolk sac at this age. AFP is subsequently expressed in the mesonephros and transiently in the developing pancreas. In the mouse, no expression of AFP was observed in the mesonephros but other sites of expression were similar. Thus AFP has a distinct temporospatial expression pattern during the embryonic period and this differs between human and mouse species. It is interesting that AFP is expressed by tumours such as primitive gastrointestinal, renal cell and pancreatic tumours as well as those of hepatocyte origin. This distribution reflects the sites of AFP expression during development.     

含生长抑素mRNA神经元在移植视网膜发育中的表达

将６０例鼠龄１４ｄＳＤ大鼠视网膜移植到出生后１ｄ大鼠中脑偏左侧处，同时摘除新生鼠的右眼。术后１０ｄ至２２ｄ分别取移植视网膜及其中脑，在相应的年龄取正常视网膜作对照，应用原位杂交组化技术──地高辛标记的生长抑素的ｃＲＮＡ探针检测移植和正常视网膜中含生长抑素ｍＲＮＡ神经元出现时间、发育规律及定位分布。同时用免疫组化方法显示生长抑素免疫反应神经元的形态，以作对照和补充。原位杂交组化实验结果表明：在出生当天的移植视网膜节细胞层已出现阳性表达，出生后４ｄ，外核层也出现小的含生长抑素ｍＲＮＡ神经元，此种神经元随后减少、消失；与此同时内核层及节细胞层内含生长抑素ｍＲＮＡ神经元逐渐增多，至生后１２ｄ接近成年水平。通过对非移植大鼠视网膜进行正常对照观察，移植视网膜与非移植的正常视网膜生后发育的结果相似。生长抑素免疫反应神经元与原位杂交含生长抑素ｍＲＮＡ神经元的表达部位是一致的，但生长抑素免疫反应神经元可见其突起。     

Experimental study of the development of the truncus arteriosus of the chick embryo heart. I. Time of appearance

The time of appearance of the truncus arteriosus was studied in the chick embryo using an in ovo labeling technique. Three hundred embryos at stages 13–18 of Hamburger and Hamilton were selectively labeled at the distal end of the heart tube, using gelatine-india ink label; 122 of these embryos were reincubated and 111 of them reached stages 25–28. In these stages the final location of the label was determined. Only 95 of these embryos showed both a normal heart and a label located in it. The remaining embryos were discarded due to abnormal cardiac morphology or because the label was not found. Embryos labeled at stages 13–14 had label in the conus in 42.8% of the cases and in the boundary between the conus and the truncus arteriosus in 57.1% of the cases. Label placed at stages 15–16 was located in the conus in 6.1% of the cases, in the boundary between the conus and the truncus arteriosus in 44.8% of the cases, and in the truncus arteriosus in 48.9% of the cases. Finally, label placed at stages 17–18 was located in the boundary between the conus and the truncus arteriosus in 18.7% of the cases and in the truncus arteriosus in 81.2% of the cases. Our results permit us to conclude that the truncus arteriosus appears in the chick embryo as early as stages 15–16 of Hamburger and Hamilton (50–56 hours of incubation). © 1993 Wiley-Liss, Inc.     

胰岛素、可地松和已烯雌酚处理妊娠早期小鼠对其胚胎发育的影响

本文用不同剂量的胰岛素、可地松、已烯雌酚,作用于妊娠开始至80小时的昆明小鼠,然后观察胚胎早期(植入前)和胚胎晚期(妊娠18天)的胚胎数量、发育时期及其与黄体数相比成活率的变化。实验表明,用较大剂量激素处理后,早期胚胎的上述各项指标,均表现出十分明显的抑制效果。当剂量逐渐降低后,仍表现出不同程度的抑制作用,只是逐渐趋于正常。所用各种激素对晚期胚胎的影响,表现在除部分死亡外,存活者的生长和发育一直落后。说明妊娠早期小鼠体内某些激素的水平,不仅直接影响早期,而且也影响晚期胚胎的发育。     

Determination of total body water by multifrequency bio-electric impedance: development of several models

Multifrequency bio-electronic impedance analysis (MF BIA) measurements are taken from a heterogeneous group of patients, varying in size between obese and slim. The measuring system uses four electrodes: two current and two potential electrodes. Three new models are developed to calculate total body water (TBW) from the BIA data, and the resulting TBW values are compared with TBW determined by D₂O dilution. The results demonstrate that the most simple model provides the best TBW values. For individual patients, TBW can be determined by means of bioimpedance measurement with an accuracy of 3 litres. In the most simple model (model 1), the body is electrically represented by a cylinder, and corrections are made for the amount of fat. This is an extension of the model used by Xitron. In the more advanced models (2 and 3), the body is represented by a cylinder for the trunk, and truncated cones represent the arms and legs. In model 2, ΔTBW amounts to 3 litres. It is shown that the resistance of the trunk is proportional to the square root of the length. In model 3, it is assumed that subcutaneous fat is a poor conductor if electric current. An equation is developed that describes the partition of subcutaneous fat, and the fat layer is then removed from the cones representing arms and legs and from the cylinder that models the trunk.