带血管大鼠胸腺移植的应用解剖

目的 明确大鼠胸腺解剖,设计带血管大鼠胸腺移植模型.方法 对10只6～8周龄SD供体大鼠胸腺动脉的起源、静脉回流进行观察研究,设计带血管的大鼠单侧叶和双侧叶胸腺移植物血管蒂.15只6～8周龄SD受体大鼠分为左侧叶、右侧叶和双侧叶胸腺移植组,每组5只.观察胸腺移植物血供重建情况,并就供胸腺摘取方法、供吻合的血管蒂进行讨论...     

幼儿胸腺的应用解剖学

目的:对童尸胸腺进行应用解剖学研究,为胸腺手术和经皮胸腺穿刺术提供解剖学依据.方法:30例福尔马林固定童尸标本,解剖观测胸腺的形态、大小、位置与毗邻以及血液供应.结果:30例胸腺均为2叶型,左叶长、宽、厚度为59.41、23.74、8.02 mm,右叶长、宽、厚度为60.20、22.49、8.39 mm;左叶上极80.0%高出颈静脉切迹,最高1例高出至甲状腺下缘,而右叶上极63.3%高于颈静脉切迹而无高出至甲状腺下缘者;两侧叶下极48.3%平对第3肋软骨或其上、下缘处;两侧缘76.7%超出胸骨两侧缘;胸腺两侧叶动脉的来源72.0%来自于同侧的胸廓内动脉或甲状腺下动脉,静脉93.2%汇入头臂静脉或甲状腺下静脉.结论:幼儿胸腺的形态、位置变异较大,血供呈多源性.掌握其形态学特点对于胸腺疾病的诊断和治疗具有重要的应用价值.     

单侧完全性唇腭裂胎儿宫内手术修复的解剖学基础

目的　为单侧性唇腭裂胎儿宫内手术修复提供解剖学基础。 方法 制作和观察21～32周正常和单侧完全性唇腭裂胎儿头颈部血管铸型标本,比较他们唇腭部血供的来源及吻合情况。 结果 ①正常胎儿唇腭部的血供主要由上唇动脉、鼻翼下缘动脉和腭大动脉组成。两侧上唇动脉在中线附近吻合成上唇动脉弓,并在鼻中隔前下部形成浅深两层血管网,且上唇动脉鼻中隔支也与腭大动脉穿支相互吻合;②单侧完全性唇腭裂胎儿唇腭部血供由于患侧裂隙的阻隔,导致左右上唇动脉不能吻合成弓,患侧腭大动脉穿过骨残端与患侧鼻腔内的血管相吻合。 结论 单侧完全性唇腭裂胎儿唇腭部血管非常丰富,尤以上唇动脉和腭大动脉为血供主干。     

单侧完全性唇腭裂胎儿颌面部血供的应用解剖

目的为单侧完全性唇腭裂胎儿宫内手术修复提供解剖学基础。方法制作和观察21～32周正常和单侧完全性唇腭裂胎儿头颈部血管铸型标本,比较它们颌面部血供的来源及吻合情况。结果①正常胎儿颌面部血供主要来源于面动脉、颏下动脉、下唇动脉、上唇动脉、鼻翼下缘动脉、鼻翼动脉、鼻外侧动脉、鼻背动脉、眶下动脉及面横动脉等,这些动脉及其分支构筑颌面部组织丰富的血管网;②单侧完全性唇腭裂胎儿患侧上唇动脉沿裂缘向上至鼻翼基底部与鼻翼下缘动脉等相吻合,患侧部分腭骨缺损暴露的腭大动脉穿过骨残端与患侧鼻腔内的血管相吻合。结论对单侧完全性唇腭裂胎儿颌面部进行宫内修复手术,重点在鼻部和上唇部的血供,主要以上唇动脉、鼻翼下缘动脉和腭大动脉为主。     

人脾血管吻合的研究

用ＡＢＳ铸型的方法对５０例胎儿和新生儿脾内，外血管吻合进行了观察，结果：（１）脾存在较为广泛的血管血合，共发现２７例４８处静脉属支间的吻合，３１例５１例处脾支间的吻合。（２）静脉间的吻合多位于上、下极附近，叶、段间的吻合少且细弱。动脉间的吻合多位于脾门和上极附近，近半数的吻合位于叶间或段间，故在脾叶、段切除时应慎重。（３）脾外吻合多为短交通支形，弓形吻合绝大部分位于脾内，汇集形动脉吻合多存在于叶间     

腓肠神经的营养血管临床应用解剖研究

目的研究腓肠神经营养血管的解剖特点，为临床设计腓肠神经营养血管逆行皮瓣，提供解剖学基础。方法采用人体标本全身动脉灌注填充剂和局部解剖血管铸型方法，观察测量腓肠神经营养血管来源、吻合情况及相关数据。结果腓肠神经营养血管来源于腓肠内、外侧皮神经的营养动脉、胭窝内、外侧皮动脉及胭窝中间皮动脉。此动脉在小腿下1／3段与腓动脉肌间穿支吻合成血管网。结论腓肠神经营养血管有多源性、吻合丰富的特点，以腓肠神经营养血管设计逆行皮瓣，血供较好，修复足部软组织缺损能获得较好效果。     

胎儿胸腺发生与中枢神经系关系的研究

以无脑儿作为天然实验材料,观察胎儿脑腺发生与中枢神经系的关系。在无脑儿胸腺内,上皮性网状细胞、胸腺小体发育不良,但胸腺的体积异常增大。由于胎儿肾上腺皮质激素缺乏时可引起胸腺的异常增大,以及在无脑儿时肾上腺皮质萎缩。因此,我们认为:中枢神经系,通过下丘脑→脑垂体→腎上腺皮质→胸腺上皮性网状细胞,调节胸腺内淋巴细胞的分化与成熟。在无脑儿,由于上皮性网状细胞的功能受抑制,使淋巴细胞的分化成熟受阻,以致大量淋巴细胞积聚在胸腺内,导致其体积异常增大。     

前臂皮瓣筋膜血管的解剖学

系统并定量研究前臂皮瓣筋膜的血管，以补文献之不足并为临床应用提供形态学基础。对１４例成人标本进行了巨微解剖，组织透明，切片观察和图像分析，前臂筋膜四种动脉来源以肌间隙皮动脉为主，肌间隔或肌间隔皮动脉吻合成链，各种源动脉在深筋膜有浅，深支而以浅支多而粗，深筋膜浅，深血管网也以前者较密，深筋膜血管组织面积比值大于浅筋膜。深筋膜血管特别是深筋膜浅血管网是前臂筋膜皮瓣的血供基础，筋膜蒂宜放在血管链状吻合处     

带骨骺的儿童腓骨移植应用解剖学

解剖观察了70侧的儿童腓骨上骨骺的动脉来源、分布和吻合情况。其血供来源共见7种,胫前返动脉和腓浅动脉的腓骨头支是营养骨骺的重要血管。带骨骺儿童腓骨移植应以胫前动脉为血管蒂,腓骨体移植仍以腓血管为蒂。     

第9、10、11肋间神经和肋下神经的血供

本文观察了25具成人专供研究用的尸体,对50侧第9、10、11肋间神经和肋下神经的血供进行了研究,对该四对神经的营养动脉数目、外径、长度、入神经干部位和来源动脉进行观察测量。发现营养动脉外径较细,长度亦较短,不宜作为肋间神经的血管蒂进行吻合,而肋间神经营养动脉的来源动脉——肋间后动脉,其外径较粗,并有足够长度,作为血管蒂进行吻合较为理想。     

Estrogen Inhibits Fetal Thymocyte Development In Vitro

PROBLEM: Transient involution of the maternal thymus in mice is known to occur during pregnancy. We have previously reported that the hormone responsible for this involution is estrogen. Interestingly, although estrogen crosses the placenta, fetal thymus gland enlarges with advancing gestational age. It is not known if fetal thymocytes are resistant to estrogen or if there are other factors that prevent estrogen from exerting an effect on the development of fetal thymocytes. Therefore we studied the effect of estrogen on isolated fetal thymic glands in vitro. METHOD OF STUDY: Pregnant Balb/c mice were sacrificed at 15 days gestation and fetal thymic lobes were obtained from all fetuses. The glands were cultured in vitro using either control medium or medium to which estrogen was added in two concentrations of 0.5 mg/ 100 ml and 1.0 mg/100 ml. After 12 days of organ culture, total thymocyte counts and phenotypic analysis by three color flow cytometry were performed by using monoclonal antibodies to surface markers of T cell subsets. RESULTS: Estrogen treatment caused a marked suppression of the total number of fetal thymocytes. All CD4 and CD8 defined T cell subsets were reduced with a disproportionate loss of CD4+ single positive (SP), CD8+ SP; CD4+CD8+ double positive (DP) cells. The early thymocyte developmental stages, based on CD44 and CD25 expression, revealed the CD4-CD8-CD3- triple negative compartment (TN) to be composed of almost entirely the earliest population (CD44+CD25-) with the remaining maturational stages depleted. CONCLUSIONS: This study demonstrates that fetal thymus removed from the intact fetus is susceptible to the inhibitory effects of estrogen. Since the fetal thymus enlarges with advanced gestational age, it is clear that the intact fetus invokes a regulatory mechanism which neutralizes the anti-lymphopoietic action of estrogen observed in the adult female.     

The aged thymus shows normal recruitment of lymphohematopoietic progenitors but has defects in thymic epithelial cells

Aging is associated with reduced numbers of all thymocyte sub-populations, including early T-cell progenitors. However, it is unclear if this is due to inadequate recruitment of lymphohematopoietic progenitor cells (LPCs) to the aged thymus or to abnormal development of T cells within the thymus. We found that LPCs from young mice were recruited equally well to the thymi of young or aged mice and that thymic stromal cells (TSCs) from young and old mice expressed similar levels of P-selectin and CCL25, which are believed to mediate recruitment of LPCs to the adult thymus. However, the number of recruited thymocytes in old thymus was markedly reduced after two weeks, indicating that T-cell development or proliferation is defective in the aged thymus. We also found that LPCs from aged and young mice have similar capacities to seed a fetal thymus that was transplanted under the kidney capsule. Thymic epithelial cells (TECs) in aged mice had lower proliferative capacity and higher rate of apoptosis, compared with findings in young animals. In addition, immunofluorescence staining with antibodies to cortical and medullary TECs revealed that aged thymi had a disorganized thymic stromal architecture, combined with reduced cellularity of the medulla, and apoptosis of thymocyte sub-populations in the medullary microenvironment was increased, compared with that in young mice. We conclude that aging does not impair recruitment of LPCs to the thymus, but is characterized by abnormalities in thymic epithelial architecture, especially medullary TEC function that may provide sub-optimal support for thymic development of LPCs.     

IL-18 produced by thymic epithelial cells induces development of dendritic cells with CD11b in the fetal thymus

Thymic dendritic cells (DCs) are suggested to be involved in T cell selection; however, their exact origin and function remain to be established. Although DCs in the adult thymus are mostly CD8alpha(+)CD11b(-), we found that CD8alpha(-)CD11b(+) DCs were abundantly present in the fetal thymus and they possessed antigen-presenting activity. Interestingly, these CD11b(+) DCs were significantly decreased in mice deficient for TNFR-associated factor 6 (TRAF6), a key signaling molecule downstream of IL-1 and tumor necrosis factor-alpha that have been known to induce DCs from intra-thymic precursor cells. CD11b(+) DCs were induced from CD4(-)CD8(-) thymocytes by fetal thymic epithelial cells (TECs). Analysis of cytokine expression in TECs revealed that none of the cytokines previously shown to induce DCs were expressed. Instead, we found strong expression of IL-18 that transmits signals through TRAF6. IL-18 induced CD11b(+) DCs from CD4(-)CD8(-) thymocytes in vitro, which exhibited strong antigen-presenting activity and formed conjugates with CD4(+)CD8(+) T cells efficiently. Taken together, these results strongly suggest that CD11b(+) DCs are differentiated from CD4(-)CD8(-) thymocytes by IL-18 produced from TECs and that they are involved in T cell selection in the fetal thymus.     

An immune system switch at birth triggers a change in the lifespan of peripheral T cells

Lymphocyte recirculation is an essential element in the integration of immune responses and is an absolute requirement for the development of systemic memory in postnatal animals. During foetal life a large pool of recirculating T cells develops and migration pathways of naive T cells to skin and peripheral tissues as well as LN are established. At birth a process is triggered whereby naive fetal T cells are rapidly lost from the circulating pool and are replaced by newly arriving T cells which have been formed since birth. At present our data suggest that the thymic export in the fetus creates a pool of long-lived naive T cells of wide diversity. The situation in neonatal lambs is more complex since the thymus is exporting large numbers of short-lived thymic emigrants which enter a peripheral T-cell population where many T cells are dividing.     

Epithelial-cell architecture during involution of the human thymus

One hundred thymus glands were assessed histologically as to their degree of involution. Epithelial cells were demonstrated by an immunoperoxidase method using a monoclonal antibody against cytokeratin. The distribution of these cells was studied in the medulla, the cortico-medullary junction, the cortical parenchyma and the subcapsular cortex. As involution proceeds, the loss of cells from the thymus is almost totally confined to the lymphoid-cell elements. The architecture of the epithelial-cell network remains largely intact although there is extensive collapse of the structure due to the loss of the intervening lymphocytes. Even when involution is apparently complete; sheets of epithelial cells can be demonstrated in the thymic remnant.     

Purification and characterization of a human sialoglycoprotein antigen expressed in immature thymocytes and fetal tissues

Abstract: The monoclonal antibody UN1 was previously produced in our laboratory on the basis of selective reactivity with human thymocytes and has been classified as unclustered by the 5th and 6th International Workshop and Conference on Human Leukocyte Differentiation Antigens. The antigen recognized by mAb UN1 was found to be expressed on the cell surface of immature human thymocytes, a subpopulation of peripheral T lymphocytes and on several fetal tissues including thymus. The UN1 antigen is purified from children's thymus by ion-exchange and affinity chrom-atography. Two-dimensional electrophoresis shows that the purified antigen displays microheterogeneity appearing as multiple spots over a pI range 4.4–5.0 at 100–120 kDa. Treatment with neuraminidase results in a retarded migration in SDS-PAGE, an increase in isoelectric point and a reduction in carbohydrate content, indicating a substantial content of sialic acid. Glyco-sidase digestion and lectin-binding analysis indicate that the carbohydrate residues are essentially O-linked. A preliminary analysis has detected the UN1 antigen in human breast carcinoma tissues but not in normal breast. The biochemical features and the pattern of expression of the UN1 antigen indicate that this molecule may have the characteristics typical of the family of cell-membrane-associated mucin-like glycoproteins; a number of these molecules are thought to have a role in cell-cell interaction, tumor progression and metastasis.     

A Common Stem Cell for Murine Cortical and Medullary Thymic Epithelial Cells?

We have addressed the question whether the epithelial stroma in the thymus is derived from a common stem cell or whether cortical and medullary epithelial cells are derived from different embryonic stem cells emerging, for example, from endoderm and ectoderm. By the use of rapidly expanding cultures of thymic epithelial cells (TEC) from 14 to 16 day-old murine fetuses and by specific antibodies against cortical and medullary epithelium, respectively, we were able to demonstrate a small subpopulation of double-labeled TEC in the cultures. These cells were not present in TEC cultures initiated from thymuses of neonatal mice. Double-labeled TEC were also found in tissue sections from fetal thymuses. These findings may indicate that TEC populations of the cortex and the medulla are derived from a common stem cell, with potential for differentiation toward both cortical and medullary TEC.     

Characterization of a 50 kDa surface membrane protein on thymic stromal cells as an important factor for early T cell development

We previously reported that the nude mouse-derived splenic Tcell clone, N-9F, exhibits a prollferative response to the SL10.3thymic epithelial cell clone. In the present study we generatedan Armenian hamster mAb, HS9, specific for SL10.3, which Inhibitedthe N-9F's proliferative response to SL10.3. We performed thymocyterepopulation experiments using fetal liver cells and 2'-deoxyguanosine-treatedthymic rudiments. After 14 days of culture, donor fetal livercells proliferated and differentiated to CD4⁺CD8⁺ and CD4^–CD8⁺with some CD4⁺CD8^– cells in the host thymic rudiments.However, most of the thymocytes remained at a CD4^–CD8^–immature stage in the presence of HS9 and the cell recoverywas reduced to 30% of the control. Immunohistostaining and flowcytometry studies revealed that HS9 reacted with stromal cellsof fetal thymus at the earliest from day 14 gestation. Neitherthymocytes nor lymph node T cells were stained with HS9. HS9antigen was distributed not only on thymic subcapsular and corticalstromal cells, but also on peripheral B cells in adult mice.The antigen that HS9 detected was found to be a 50 kDa surfacemembrane protein on thymic stromal cells. On the other hand,the 50 kDa molecule is associated with two other molecules of80 and 100 kDa on the B cells. These data indicate that theHS9 antigen may have an important role for early T cell development,especially at a stage from CD4^–CD8^– to CD4⁺CD8⁺,and may have some unknown function on B cells.