人胚胎表皮角蛋白细胞分化中PAI-2表达的研究

目的　通过研究人胚胎期表皮分化中PAI 2的表达及变化规律 ,探讨PAI 2与人表皮角蛋白细胞的关系。　方法　用免疫细胞化学及原位杂交技术对早、中、晚期人胚胎表皮角蛋白细胞染色 ,观察PAI 2蛋白及其mRNA原位分布、合成情况 ;用免疫细胞化学及核酸斑点杂交实验检测离体培养的人胚胎表皮角蛋白细胞中PAI 2的表达情况。　结果　PAI 2在人胚胎期主要存在于分化程度高的表皮浅层角蛋白细胞内。胚胎期的表达高峰在胚胎中期 ,胚胎晚期其蛋白水平开始降低 ,而mRNA则维持在相对高位。PAI 2聚集于原位及离体培养的角质蛋白细胞胞浆近胞膜处。　结论　PAI 2可能参与了表皮角蛋白细胞分化的调控。     

胎儿皮肤中CK20的表达及与Merkel细胞分布的相关性研究

目的研究不同发育时期胎儿皮肤表皮基底层中细胞角蛋白20（CK20）的分布、数量,以揭示Merkel细胞分布的规律。方法CK20是Merkel细胞特异而敏感的标记物,分别取42例不同胎龄（16—30周）胎儿掌、跖、胸、背部的全层皮肤,采用免疫组化SP法观察CK20。结果掌、跖部位CK20阳性细胞的数量显著高于胸、背部;胚胎16～20和21—25周显著高于26—30周。结论（1）表皮Merkel细胞的数量存在解剖部位的差异。（2）胚胎发育中期Merkel细胞的数量显著多于胚胎发育的晚期。（3）Merkel细胞在表皮突内的高表达可能与表皮突结构的形成有关。     

利用载有角质细胞生长因子微囊的组织工程皮肤修复裸鼠皮肤缺损

背景：组织工程皮肤作为一项新兴技术拥有良好的应用前景。有研究表明,角质细胞生长因子可以促进表皮细胞增殖。 目的：观察荷载角质细胞生长因子纳米微囊的新型组织工程皮肤修复裸鼠皮肤缺损的效果和特点。 方法：构建荷载角质细胞生长因子的脱细胞真皮基质复合物;将人表皮干细胞群和成纤维细胞分离、培养,并且进行鉴定;将表皮干细胞群接种于复合物之上,观察其生长状况;将荷载角质细胞生长因子纳米微囊的组织工程皮肤移植于裸鼠皮肤缺损处,将无角质细胞生长因子纳米微囊的组织工程皮肤作为空白组,将其自体皮肤移植修复缺损组作为对照组,于移植后2,4,6周时观察皮片挛缩及组织学愈合情况,并应用抗人角蛋白10及β1-整合素免疫荧光检测修复区表皮和真皮层细胞来源、分化及生长情况。 结果与结论：表皮干细胞在复合物表面生长良好,黏贴紧密,可见有连接成片趋势的小圆形的表皮干细胞及多角形的终末表皮细胞,部分形成克隆团块。移植后第2,4,6周,荷载角质细胞生长因子纳米微囊组织工程皮肤修复裸鼠皮肤缺损的结果均优于空白组及对照组,移植的皮肤边缘与邻近皮肤完全融合,但存在一定程度的挛缩。修复区组织工程皮肤的表皮细胞分层良好并能产生角质层,同时,移植后8,10周,组织工程皮肤切片免疫荧光染色可以鉴别出少量β1-整合素阳性细胞,均为表皮干细胞或短暂扩充细胞。结果证实,荷载角质细胞生长因子纳米胶囊的新型组织工程皮肤修复裸鼠皮肤缺损的效果较好,优于普通组织工程皮肤及自体全厚皮片移植修复。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程     

基底型细胞角蛋白在乳腺周围型导管内乳头状肿瘤诊断中的应用

目的比较不同类型基底型细胞角蛋白（CK5/6、34βE12）在周围型乳头状肿瘤中的辅助诊断价值并结合CK8和肌上皮标记（p63、SMA）对乳头状肿瘤中的增生细胞成分进行初步分析。方法参照2003年WHO乳腺疾病分类的诊断标准,筛选出乳头状瘤伴普通型增生（UH）10例,伴不典型增生（AH）10例,导管内乳头状癌（IDPC）8例。所有病例均进行CK5/6、CK8、34βE12、p63和SMA免疫组化染色。结果乳头状瘤伴UH、AH及IDPC时,CK5/6在增生细胞中的阳性表达率分别为9/10、3/10、0/8;34βE12的阳性表达率分别为10/10、4/10、1/8。CK8在增生细胞中均为阳性,在乳头基底部和导管周围细胞中均为阴性。p63和SMA在增生细胞中均为阴性,在乳头基底部和导管周围细胞中有不同程度的阳性。结论基底型CK结合CK8和肌上皮标记有助于乳头状瘤是否伴UH、AH或IDPC的鉴别诊断。乳头状瘤伴上皮增生时有多种细胞成分参与,包括定向干细胞、腺中间细胞和腺终端细胞等,但未发现具有肌上皮特点的细胞参与其中。     

利用载有角质细胞生长因子微囊的组织工程皮肤修复裸鼠皮肤缺损（英文）

背景:组织工程皮肤作为一项新兴技术拥有良好的应用前景。有研究表明,角质细胞生长因子可以促进表皮细胞增殖。目的:观察荷载角质细胞生长因子纳米微囊的新型组织工程皮肤修复裸鼠皮肤缺损的效果和特点。方法:构建荷载角质细胞生长因子的脱细胞真皮基质复合物;将人表皮干细胞群和成纤维细胞分离、培养,并且进行鉴定;将表皮干细胞群接种于复合物之上,观察其生长状况;将荷载角质细胞生长因子纳米微囊的组织工程皮肤移植于裸鼠皮肤缺损处,将无角质细胞生长因子纳米微囊的组织工程皮肤作为空白组,将其自体皮肤移植修复缺损组作为对照组,于移植后2,4,6周时观察皮片挛缩及组织学愈合情况,并应用抗人角蛋白10及β1-整合素免疫荧光检测修复区表皮和真皮层细胞来源、分化及生长情况。结果与结论:表皮干细胞在复合物表面生长良好,黏贴紧密,可见有连接成片趋势的小圆形的表皮干细胞及多角形的终末表皮细胞,部分形成克隆团块。移植后第2,4,6周,荷载角质细胞生长因子纳米微囊组织工程皮肤修复裸鼠皮肤缺损的结果均优于空白组及对照组,移植的皮肤边缘与邻近皮肤完全融合,但存在一定程度的挛缩。修复区组织工程皮肤的表皮细胞分层良好并能产生角质层,同时,移植后8,10周,组织工程皮肤切片免疫荧光染色可以鉴别出少量β1-整合素阳性细胞,均为表皮干细胞或短暂扩充细胞。结果证实,荷载角质细胞生长因子纳米胶囊的新型组织工程皮肤修复裸鼠皮肤缺损的效果较好,优于普通组织工程皮肤及自体全厚皮片移植修复。     

糖尿病模型皮肤创面中人真皮多能干细胞向表皮细胞的分化

背景：研究表明,干细胞分化为何种细胞与其所处的微环境密切相关。因此设想：人真皮多能干细胞处于皮肤创面的微环境中,可能具有向人皮肤细胞转化的潜能。 目的：探讨糖尿病皮肤创面微环境中的人真皮多能干细胞分化为表皮细胞的可能性。 方法：分离培养人真皮多能干细胞并制作糖尿病裸鼠模型皮肤创面,将标记5-BrdU的第3~5代人真皮多能干细胞以注射方式回植入糖尿病裸鼠创面组织周围,分别于注射后2,3周取材,常规石蜡包埋、连续切片,行BrdU和角蛋白免疫组织化学染色。 结果与结论：BrdU阳性细胞出现在表皮中,且连续切片中部分BrdU阳性细胞也同时表达角蛋白。说明在糖尿病创面愈合过程中,人真皮多能干细胞具有向表皮细胞分化的潜能。     

体外培养人骨髓间充质干细胞向表皮细胞分化及表皮细胞角蛋白的表达

背景：动物实验已经证实骨髓间充质干细胞体外诱导可分化为表皮细胞。 目的：观察体外培养条件下人骨髓间充质干细胞向表皮细胞的分化及表皮细胞角蛋白表达。   方法：采用Ficoll-Paque密度梯度离心法提取人胚胎骨髓间充质干细胞,以免疫细胞化学及流式细胞仪测定细胞表面CD33、CD34标记物进行鉴定。取第3代骨髓间充质干细胞以30%条件培养基诱导其向表皮细胞分化,免疫细胞化学染色观察诱导后细胞形态与细胞角蛋白水平变化。 结果与结论：采用密度梯度离心法从人胚胎骨髓中分离培养得到细胞成分均一的骨髓间充质干细胞。骨髓间充质干细胞经体外诱导后,出现细胞角蛋白19表达阳性细胞,说明骨髓间充质干细胞在体外诱导后可能发生向表皮细胞分化。     

基底型细胞角蛋白在乳腺导管内增生性病变诊断中的应用

目的比较不同类型基底型细胞角蛋白(CK5、CK34βE12和CK14)在乳腺导管内增生性病变中的辅助诊断价值,并结合肌上皮标记、超微电镜对普通型导管增生的细胞成分进行初步分析。方法参照2003年WHO乳腺疾病分类的诊断标准筛选出28例导管普通型增生(UDH)、10例不典型增生(ADH)和25例导管原位癌(DCIS)。所有病例均进行CK5/6、CK34βE12、CK14、CK8、浕SMA、calponin和p63的免疫组化染色。4例UDH和1例DCIS通过电镜观察其增生细胞的超微结构。结果CK5/6在UDH、ADH和DCIS增生细胞中的阳性表达率分别为92.9%、10.0%和0。CK34βE12和CK14的阳性表达率分别为96.4%和82.1%(UDH)、20.0%和30.0%(ADH)、24.0%和28.0%(DCIS)。所有UDH的增生细胞均不表达浕SMA、calponin和p63。电镜观察显示UDH和DCIS的增生细胞中未发现符合肌上皮超微特征的细胞存在。结论基底型CK有助于UDH和ADH/DCIS的鉴别诊断,其中CK5/6较CK34βE12和CK14特异性更高。免疫组化染色和电镜观察结果支持UDH的增生细胞含有多种成分,包括定向干细胞、腺中间细胞和腺终端细胞等,但未发现具有肌上皮特点的细胞参与其中。     

感染HCMV的腮腺导管上皮细胞CK和EMA丢失

目的 研究人类巨细胞病毒(HCMV)感染对腮腺导管上皮细胞表型产生的影响。方法 用免疫组化方法检测腮腺巨细胞包涵体病石蜡包埋组织中巨细胞病毒以及早期抗原、CK、EMA等的表达．结果 腮腺导管上皮细胞感染人巨细胞病毒后，作为上皮性标志物的CK和EMA表达呈阴性。结论 人巨细胞病毒感染腮腺导管上皮细胞使其CK和EMA丢失。单层上皮角蛋白网具有维持上皮细胞机械力学完整性的功能。     

核因子-κB介导肿瘤相关巨噬细胞对骨肉瘤增长的影响及其作用机制的实验研究

目的 探讨核因子-κB(NF-κB)介导肿瘤相关巨噬细胞(TAMs)对骨肉瘤增长的影响及其作用机制。方法 选取4~6周无特定病原体级Balb/c雄性裸鼠15只,数字表法随机分为人骨肉瘤MG63细胞组、人单核巨噬细胞系THP-1细胞组、MG63+THP-1混合细胞组3组,每组5只。于裸鼠右侧腋窝皮下注射浓度为1.0×10⁸/mL的不同细胞悬液制备裸鼠成瘤模型:MG63细胞组裸鼠每只注射MG63细胞悬液0.2 mL,THP-1细胞组裸鼠每只注射THP-1细胞悬液0.2 mL,MG63+THP-1混合细胞组裸鼠每只注射MG63+THP-1混合细胞悬液(9∶1)0.2 mL。注射细胞后每天观察各组裸鼠是否出现移植瘤,从MG63组和MG63+THP-1混合细胞组均出现移植瘤当天开始,用游标卡尺测量移植瘤的长径和短径,并计算移植瘤体积,此后每5天测量1次,对比不同时间各组移植瘤生长情况;注射细胞后第25 天处死裸鼠,剥离移植瘤,对比各组移植瘤质量。将移植瘤置于10%甲醛中固定,制备石蜡切片,采用HE染色,观察各组移植瘤的肿瘤特征改变;采用免疫组织化学SP染色,观察各组移植瘤中核转录因子NF-κB蛋白的表达情况;采用Image-Pro Plus 6.0图像分析软件定量分析比较各组移植瘤中NF-κB蛋白的表达水平。结果 THP-1细胞组裸鼠没有形成移植瘤。MG63+THP-1混合细胞组和MG63细胞组的裸鼠分别从注射细胞后第7 天、第10天开始腋窝皮下可触及移植瘤,且随时间增加,肿瘤体积逐渐增大;第10、15、20和25 天 MG63+THP-1混合细胞组裸鼠移植瘤体积分别为(474.4±56.1)、(945.0±79.7)、(2 886.0±462.3)、(3 319.6±388.4)mm³,均明显大于MG63细胞组的移植瘤体积(233.3±28.2)、(669.6±75.9)、(1 464.0±135.2)、(2 068.0±223.2)mm³,差异均有统计学意义(t=3.536、2.504、2.952、2.794, P值均＜0.05)。在种植细胞后第25天处死裸鼠,MG63+THP-1混合细胞组移植瘤质量(0.920±0.134)g,明显大于MG63细胞组(0.544±0.079)g,差异有统计学意义(t=2.404, P＜0.05)。移植瘤HE染色显示,MG63细胞组和MG63+THP-1混合细胞组移植瘤均可见明显的肿瘤特征改变。免疫组织化学SP染色显示,NF-κB蛋白在MG63细胞组和MG63+THP-1混合细胞组移植瘤组织和组织间隙均呈高表达状态;检测NF-κB蛋白表达水平,MG63+THP-1混合细胞组NF-κB蛋白吸光度值(0.362±0.006),明显大于MG63细胞组NF-κB蛋白吸光度值(0.326±0.006),差异有统计学意义(t=9.895, P＜0.05)。结论 TAMs可以促进骨肉瘤的增长,其作用机制可能与NF-κB蛋白高表达有关。     

Utility of CK7 and CK20 immunohistochemistry in the detection of synchronous breast and colon carcinoma in a pleural effusion: a case report and supporting survey of archival material

We present a case of synchronous breast and colon carcinoma in a pleural effusion, to our knowledge the first such reported case in the English-language literature. The patient was a 55-yr-old white female with known metastatic breast and colon carcinoma who developed a malignant pleural effusion which demonstrated two strikingly different populations of malignant cells by immunohistochemical study of cell block material. One cell population demonstrated a cytokeratin (CK)7+/CK20-/ER+ phenotype, while the other demonstrated a CK7-/CK20+/ER- phenotype, consistent with breast and colon origin, respectively. An immunohistochemical survey of archival breast and colon primary and metastatic carcinomas confirmed the established CK7+/CK20- phenotype of breast and CK7-/CK20+ phenotype of colon primary carcinomas, and the maintenance of this phenotype in metastases thereof. A survey of benign and malignant mesothelial lesions confirmed the absence of staining for estrogen receptor, but showed 6/10 cases weakly positive for CK20, which has not been described in other published series. This unusual case graphically illustrates the utility of cytokeratin subset immunohistochemistry in effusion cytology.     

Cytokeratin (CK5, CK8, CK14) expression and presence of progenitor stem cells in human fetal thymuses

The aim of the current study was to observe the expression of cytokeratins in human fetal thymuses. Specific cytokeratin markers in adult humans and mice have been well described but there has been little similar work on human fetuses. We also aimed to see whether progenitor stem cells that could be harvested to treat various immunodeficiency disorders are present in fetal thymic tissue. Thymuses obtained from 30 aborted human fetuses (12 to 31 weeks) were examined immunohistochemically to investigate changes in cytokeratin expression in the epithelial cells (TEC) at various gestational ages. Before 16 weeks of gestation, cortical (cTEC) and medullary (mTEC) TEC exhibited homogenous staining for cytokeratins CK8 and CK5. After 16 weeks there was differential staining, with cTEC positive for CK8 and mTEC for CK5 and CK14. Interestingly, both CK5 + CK8+ progenitor stem cells were present in the fetal thymic cortex at all gestational ages, with a relatively high number from 12 to 16 weeks. Cytokeratin expression in fetal thymuses was quite different from that in the adult thymus owing to the presence of undifferentiated progenitor stem cells in fetal thymic stroma along with differentiated TEC. The best time to harvest these progenitor stem cells from fetal thymic stroma in order to treat various immune deficiency disorders appears to be 12–16 weeks. Clin. Anat. 29:711–717, 2016. © 2016 Wiley Periodicals, Inc.     

Cytokeratin CK20 is a sensitive marker for Crooke's cells and the early cytoskeletal changes associated with hypercortisolism within pituitary corticotrophs

Crooke's cells are nonneoplastic corticotroph cells found in the adenohypophysis of patients who have an endogenous or exogenous excess of glucocorticoids. Classic Crooke's cells have a prominent hyaline cytoplasmic ring that displaces the basophilic granules of the normal cell. This characteristic appearance is produced by a perinuclear accumulation of cytokeratin filaments. Immunohistochemistry for cytokeratins is a sensitive way to identify Crooke's cells, but a keratin antibody specific for Crooke's hyaline change has not been reported. Normal pituitary epithelial cells are variably reactive for many keratin antibodies but are negative for cytokeratin 20 (CK20) expression. We evaluated the use of CK20 immunohistochemistry as a marker for Crooke's cells. We examined sections from 25 pituitary glands resected from 15 patients who had undergone exogenous glucocorticoid administration and from 10 patients with an endogenous source of hypercortisolism; sections from 10 normal pituitary glands obtained at autopsy were used as controls. CK20 immunoreactivity was observed only in corticotrophs. A staining pattern consistent with classic Crooke's cells was seen in pituitary gland sections from 15 of the cases. Cells with less intense CK20 positivity were present in sections from all 25 cases. We found CK20 to be a sensitive and specific marker for Crooke's cells and also for the previously unrecognized, subtle, cytoskeletal changes that occur in corticotrophs in response to hypercortisolism.     

ES细胞源性表皮干细胞在皮肤缺损创面的分化

目的探讨ES细胞源性表皮干细胞移植入小鼠全层皮肤缺损后对创面的修复作用,为组织工程皮肤的研究提供新的思路。方法将羊膜诱导后的带有核荧光标记的ES细胞源性表皮干细胞以生物膜为载体,覆盖小鼠全层皮肤缺损创面。术后1～8周连续取材,HE染色观察,苏丹Ⅲ染色,β1整合素、CK15、CK19、CEA免疫组化荧光双标观察。结果术后2周,创面完全长合,较厚的新生皮完全覆盖创面,基底层细胞增生,形成细胞柱伸向真皮层,真皮层中可见管腔样结构,4周后新生表皮开始变薄,新生表皮下可见毛囊样、汗腺样、皮脂腺样等结构,皮脂腺样结构苏丹Ⅲ染色阳性。免疫双标结果显示,1～4周新生表皮基底层细胞呈β1整合素、CK19阳性,真皮层中带有核标记的管状或泡状结构呈CK15、CEA阳性。结论ES细胞源性表皮干细胞在小鼠全层皮肤缺损创面可分化为表皮样、汗腺样、毛囊样和皮脂腺样等结构的潜能。     

胚胎干细胞源性表皮干细胞对小鼠全层皮肤缺损的修复

目的 研究129小鼠胚胎干细胞(ES cell)源性表皮干细胞在同种小鼠全层皮肤缺损的生长和分化,探讨Es细胞源性表皮干细胞对全层皮肤缺损的修复作用.方法 以生物膜为载体,将羊膜诱导后带有核荧光标记的ES细胞源性表皮干细胞直接覆盖小鼠全层皮肤缺损创面.术后1～8周连续取材,HE染色,β1整合素、CK15、CK19、CK10、CEA免疫组织化学和荧光双标显色.结果 术后2周,创面完全长合,较厚的新生皮覆盖创面,基底层细胞增生,形成许多大小不一的细胞柱伸向真皮层,真皮层中可见管腔样结构,免疫荧光双标显示,1～3周新生表皮中可见核标记的细胞呈β1整合素、CK15阳性,真皮层中带有核标记的管状或泡状结构呈β1整合素、CK15阳性;4周后新生表皮开始变薄,基底层细胞呈CK19、CK10阳性,汗腺样结构呈CEA阳性,6～8周新生表皮下可见毛囊样、汗腺样、皮脂腺样等结构.结论 ES细胞源性表皮于细胞植入小鼠全层皮肤缺损创面,可修复缺损的表皮,并在其下真皮层内具有分化为汗腺样、毛囊样和皮脂腺样结构的潜能.     

ES细胞源性表皮干细胞与类真皮构建组织工程皮肤的体内分化

目的以ES细胞源性表皮干细胞为种子细胞与类真皮构建组织工程皮肤,探讨其在体内的分化。方法胎鼠皮肤成纤维细胞和大鼠骨髓基质干细胞(BMSCs),分别与复合凝胶-明胶海绵构建类真皮(类真皮Ⅰ、Ⅱ),植入小鼠全层皮肤缺损创面,以生物膜为载体,把羊膜诱导后带有核标记的表皮干细胞覆盖在类真皮上,术后1～8周连续取材,苏木精-伊红染色,β1整合素、CK15、CK19、CK10和CEA免疫荧光双标和免疫组化观察。结果两组组织工程皮肤植入皮肤缺损3～4周后,创面完全长合,较厚新生皮完全覆盖创面,基底层细胞增生,形成短的细胞柱突向真皮层。新生表皮中可见核标记的细胞呈β1整合素、CK15、CK19阳性,真皮中的管腔样结构呈核荧光和CEA免疫组化双标阳性,4～8周新生表皮基底层细胞呈CK19、CK10阳性,新生表皮下可见毛囊样、皮脂腺样结构。结论ES细胞源性表皮干细胞为种子细胞与类真皮构建的两种组织工程皮肤在体内具有修复缺损皮肤及分化为表皮及毛囊样、皮脂腺样和汗腺样等皮肤附属结构的潜能。     

Heterogeneity of expression of cytokeratin subtypes in squamous cell carcinoma of the lung: with special reference to CK14 overexpression in cancer of high-proliferative and lymphogenous metastatic potential

In surgically resected specimens of squamous cell carcinoma (SCC) of the lung from 45 patients, we immunohistochemically examined the expression of 13 subtypes of cytokeratin (CK), the intermediate filament in cytoplasm of epithelial cells. To investigate heterogeneity of CK, its expression was compared among tumor cell nests with or without keratinization and stratification. Furthermore, the relationship between CK expression and Ki-67 labeling index or p53 expression was investigated.The tumor cell nests with keratinization showed the expression of CK1 and CK10 as a central pattern and the expression of CK14 as a peripheral pattern. The nests with stratification showed CK14 expression as a peripheral pattern, whereas those without stratification showed the expression as a diffuse pattern. The tumor cell nests showing stromal invasion with fibrosis in the marginal zone were diffusely positive for CK14. Ki-67 antigen labeling index was significantly higher in the nests where CK14 expression was diffuse or peripheral than in the nests where the expression was focal or negative. In lymph node metastases, the tumor cells often showed CK14 expression, like trabecular nests in the primary carcinoma. These results suggest that CK14 is a parameter of proliferative activity and metastatic potential of SCC of the lung.     

Identical cytokeratin expression pattern CK7+/CK20- in esophageal and cardiac cancer: etiopathological and clinical implications.

Surgical treatment and prognosis is different in esophageal, cardiac and distal gastric adenocarcinomas. Determination of the origin, in particular of adenocarcinomas situated at the gastroesophageal junction, may be difficult. It has been suggested that esophageal adenocarcinomas are characterized by a specific cytokeratin pattern, namely the CK7+/CK20- pattern. According to the same authors, this cytokeratin pattern is absent in gastric adenocarcinomas. The aim of our study is to evaluate if this cytokeratin pattern CK7+/CK20- is absent in cardiac and distal gastric adenocarcinomas. Therefore, we evaluated the combined immunohistochemical expression of CK7 and CK20 on paraffin-embedded material of 214 resection specimens for adenocarcinoma, comprising 66 esophageal, 73 cardiac and 75 distal gastric adenocarcinomas (UICC-classification). The adenocarcinomas were subtyped into intestinal- and diffuse-type according to the Lauren classification. The immunohistochemical staining was considered as positive if 50% or more of the tumor cells were stained. Statistical analysis has been performed applying the chi2-test. The tumors situated at the gastroesophageal junction, esophageal as well as cardiac adenocarcinomas, showed predominantly a CK7+/CK20- expression pattern (67 vs 68%), whereas this cytokeratin pattern is rather uncommon in distal gastric adenocarcinomas (31%, P<4 x 10(-5)). Independent of their localization, intestinal- as well as diffuse-type adenocarcinomas have a similar cytokeratin pattern. Our data show that the combined expression of CK7 and CK20 is different for the adenocarcinomas situated on both sides of the gastroesophageal junction compared to the distal gastric adenocarcinomas. However, in contrast to data in the literature, the combined expression of CK7 and CK20 has a low specificity in the distinction between esophageal and cardiac adenocarcinomas. This may suggest a similar origin (cell lineage) and thus may have an impact on therapeutic strategies.     

In vivo model of wound healing based on transplanted tissue-engineered skin

Advances in understanding the complex process of wound healing and development of novel growth factor and gene therapies would benefit from models that mimic closely the physiology of human wounds. To this end, we developed a hybrid wound-healing model based on human tissue-engineered skin transplanted onto athymic mice. Grafted tissues were infiltrated with mouse mesenchymal cells as native and foreign dermal regions fused together. Immunohistochemical staining for human involucrin revealed that the transplanted epithelium maintained its human origin, whereas the dermis was infiltrated by numerous mouse fibroblasts and blood vessels. Grafted tissues were wounded with a 4-mm punch to create full-thickness excisional wounds. At 1 and 2 weeks, the tissues were excised and assessed for reepithelialization, differentiation, and neovascularization. Interestingly, the average rate of keratinocyte migration (120 microm/day) was similar to migration rates observed in human subjects and significantly lower than migration in mouse epidermis. Immunohistochemical staining for keratin 10, laminin, and involucrin revealed a normal pattern of differentiation in the neoepidermis. Neovascularization was significantly elevated in the granulation tissue at 1 week and subsided to the level of unwounded tissue at 2 weeks postwounding. Our data suggest that skin equivalents grafted to a mouse model may serve as a realistic model of human wound regeneration. Because skin equivalents can be prepared with patient cells and genetically modified to stimulate or suppress gene expression, this model may be ideal for addressing mechanistic questions and evaluating the efficacy of biomaterials and gene therapeutics for promoting wound healing.