Apoptosis and blood–testis barrier during the first spermatogenic wave in the pubertal rat

This research explores the initial assembly of the blood–testis barrier (BTB) during puberty, when a massive physiological apoptosis in the first spermatogenic wave takes place. Fragments of testis from 14‐ to 20‐day‐old rats were studied by conventional transmission electron microscopic techniques. Lanthanum hydroxide was used as an intercellular tracer. Light microscopy was used to confirm apoptotic death when paraffin‐embedded sections were studied by TUNEL analysis. When the seminiferous cords reached the zygotene–pachytene spermatocyte level, they exhibited abundant apoptotic figures, whereas the remaining segments showed sporadic apoptosis. We found a BTB not yet assembled in the cords with zygotene–pachytene spermatocytes and abundant apoptosis. The observed apoptosis frequency diminished drastically when BTB was organized, as confirmed by the use of the tracer. Our conclusion is that the massive apoptosis found in the zygotene–pachytene spermatocytes between days 14 and 20 coincides with an open BTB. The absence of BTB could be one of the factors causing massive apoptosis of zygotene–pachytene spermatocytes, at least within the time span analyzed. The zygotene–pachytene spermatocytes are left exposed in an open environment instead of being isolated in the adluminal compartment to which they are destined. Anat Rec 290:206–214, 2007. © 2007 Wiley‐Liss, Inc.     

Testosterone-immunopositive primordial germ cells in the testis of the bullfrog, Rana catesbeiana

In amphibia, steroidogenesis remains quiescent in distinct seasonal periods, but the mechanism by which spermatogenesis is maintained under low steroidogenic conditions is not clear. In the present study, testosterone location in the testes of Rana catesbeiana was investigated immunohistochemically during breeding (summer) and nonbreeding (winter) periods. In winter, the scarce interstitial tissue exhibited occasional testosterone immunopositivity in the interstitial cells but the cytoplasm of primordial germ cells (PG cells) was clearly immunopositive. By contrast, in summer, PG cells contained little or no immunoreactivity whereas strong immunolabelling was present in the well-developed interstitial tissue. These results suggest that PG cells could retain testosterone during winter. This androgen reservoir could be involved in the control of early spermatogenesis in winter and/or to guarantee spermiogenesis and spermiation in the next spring/summer. The weak or negative immunoreaction in the summer PG cells might reflect consumption of androgen reservoir by the intense spermatogenic activity from spring to summer. Thus, besides acting as stem cells, PG cells of R. catesbeiana could exert an androgen regulatory role during seasonal spermatogenesis.     

Histochemical Study of the Emergence of Apoptosis and Altered SYCP3 Protein Distribution During the First Spermatogenic Wave in Wistar Rats

Apoptosis is a type of cell death responsible for maintaining tissue homeostasis that can occur in male gonads. The morphological and biochemical characteristics of apoptosis include cellular contraction, caspase activation, and DNA fragmentation. Dynamic processes of cell renewal and differentiation occur inside the seminiferous tubules, which are regulated by mitosis and meiosis, respectively. During meiosis, recombination is caused by assembly of the synaptonemal complex, which involves the participation of constitutive proteins, such as synaptonemal complex protein-3 (SYCP3). The present study evaluated germinal cell death in immature male rats and the distribution of the SYCP3 protein. Our results indicate that as germinal cells progress to the second meiotic stage, significant numbers of them are eliminated by apoptosis. We determined that the SYCP3 protein is not always incorporated into the structure of the synaptonemal complex but rather forms a nuclear cumulus near the inner nuclear membrane, causing many of these cells to undergo apoptosis. We propose that both the excess of the SYCP3 protein and its accumulation during the first meiotic division could contribute to the cell death of primary spermatocytes during the first spermatogenic wave in prepubertal Wistar rats. Anat Rec, 302:2082–2092, 2019. © 2019 American Association for Anatomy     

A novel branching pattern of the superior mesenteric artery found in the bullfrog (Rana catesbeiana) amphibian

The branching and distribution patterns of the superior mesenteric artery were studied in 10 adult bullfrogs ( Rana catesbeiana ) after injection of coloured latex solution into the vasculature. The abdominal digestive organs in the bullfrog were mainly supplied by the coeliac artery and the superior mesenteric artery, both of which arose as a common trunk, the coeliacomesenteric artery, from the abdominal aorta. The coeliac artery supplied the stomach, liver, gallbladder and the pancreas, whereas the first branch of the superior mesenteric artery was the splenic artery with other branches supplying the greater part of intestine. The apex of the intestinal loop was defined as the region supplied by the trunk of the superior mesenteric artery, and its intestinal branches constituted a 'nested formation' which had the following characteristics. (1) The branches of the trunk were distributed to both sides of the apex, and the distribution regions of younger branches were located more distant from the apex than those of older branches. (2) Two branches directed towards both sides of the trunk frequently made a common stem arising from the trunk. The second branch of the superior mesenteric artery constituted a secondary trunk and its distribution region could be defined as a secondary apex, since 1 of its branches also constituted a nested formation which was distributed to both sides of the primary and secondary apices. The intestinal branches of the superior mesenteric artery were divided into 4 types on the basis of their pattern of branching and course. It is suggested that the nested formation of the superior mesenteric artery in the bullfrog is a remnant of the vascular pattern of the tadpole, which possesses a double spiral mode of intestinal convolution, probably supplied by arteries with the nested formation in a latent form.     

db/db自发性糖尿病小鼠睾丸生殖细胞凋亡及相关基因Bcl-2和Bax表达

目的　研究糖尿病时生殖细胞凋亡及相关基因Bcl 2和Bax表达变化。方法　以脱氧核糖核酸末端转移酶介导的dUTP缺口末端标记法 (TUNEL)检测生殖细胞的凋亡 ,免疫组化ABC法检测凋亡相关基因Bcl 2和Bax的表达变化。结果　凋亡管数及凋亡阳性率糖尿病组均较正常高 ,而且随糖尿病病程进展呈明显增加趋势 ,对照组中随加龄二者也有增加。Bcl 2蛋白以散在的颗粒状大量分布于除精原细胞的各级生精细胞中 ,且以精子细胞质为最多。随糖尿病病变加重 ,Bcl 2表达减少 ,而且 ,糖尿病组比对照组Bcl 2表达率低。Bax蛋白比Bcl 2蛋白表达量少 ,以散在的颗粒状分布于曲细精管基底部的精原细胞和支持细胞中。随糖尿病病程进展和年龄增加 ,表达均呈增加趋势 ,而且 ,糖尿病组比对照组Bax表达率高。结论　在db/db自发性糖尿病小鼠睾丸 ,伴随生殖细胞凋亡增加 ,Bcl 2表达减少 ,Bax表达增加 ,凋亡及相关基因在糖尿病生殖功能障碍中起重要作用     

一氧化氮对大鼠睾丸生殖细胞凋亡作用的研究

目的：探讨一氧化氮（NO）对大鼠睾丸生殖细胞凋亡的影响。方法 采用MTT法观察NO对细胞增殖的抑制作用，透射电镜分析细胞结构变化，末端脱氧核苷酸转移酶（TdT）介导的原位末端标记法（TUNEL）及琼脂糖凝胶电泳检测生殖细胞DNA变化以进一步分析细胞凋亡的特征。结果：MTT法及DNA末端标记法检测表明，NO可抑制细胞增殖，诱导生殖细胞的凋亡，并呈剂量及时间依赖性，NO组细胞凋亡率明显高于对照组（P〈0．01）。透射电镜观察NO处理20h后的生殖细胞，其核染色质凝集、附着于核边缘呈新月形，核固缩、碎裂形成凋亡小体，符合凋亡细胞特征性改变。结论：一氧化氮具有促使生殖细胞凋亡形成的作用，这对不育症的研究有重要的价值。     

Quantification of immunocompetent cells in testicular germ cell tumours

The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm² of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours (P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours.     

Quantification of immunocompetent cells in testicular germ cell tumours

The immunocompetent cells present in the different histological patterns of 43 testicular germ cell tumours were evaluated. CD3 + and CD45RO + (UCHL1 +) T lymphocytes, CD68 + and MAC 387 + macrophages, CD20 + (L26 +) B lymphocytes, and kappa and lambda + plasma cells were counted. The number of immunocompetent cells per mm² of tumour tissue, excluding the necrotic areas, was evaluated. Microscopic fields were randomly selected by two observers. In order to guarantee randomization each surface was divided into parts, numbered through a lattice, and some fields were chosen via a random numbers table. This procedure yielded significantly different counts from those obtained on subjective selection. The number of T-lymphocytes and macrophages was higher in seminomas than in the non-seminomatous testicular germ cell tumours ( P < 0.05) Embryonal carcinomas had more T-lymphocytes than immature teratomas. No significant differences were found among testicular germ cell tumours with regards to the B-lymphocytes, with the exception of the high number of B-lymphocytes in mature teratomas. Kappa + and lambda + plasma cells were few in the testicular germ cell tumours. Randomization in the quantification of immunocompetent cells in testicular germ cell tumours is a good means for evaluation of immune response in all the tumour mass, not only in the areas with the most intense inflammatory cell infiltrate, and permits comparison of testicular germ cell tumours with other malignant tumours. Study of immunocompetent cells in every histological type of testicular germ cell tumour is useful in comparing them with other extra-testicular germ cell tumours.     

Apoptosis in the human liver during allograft rejection and end-stage liver disease

The contribution of apoptosis (programmed cell death) to cellular damage in human liver disease is unknown. Using the in situ DNA end labelling method (ISEL), evidence was sought of programmed cell death (PCD) in liver tissue from patients with various liver diseases. In particular, the study aimed to determine whether PCD is involved in either the loss of interlobular bile ducts (vanishing bile duct syndrome—VBDS) or the perivenular hepatocyte drop-out, both of which are characteristic of irreversible graft rejection. Large numbers of apoptotic hepatocytes were found in pervenular areas in tissues taken from patients with chronic graft rejection. Significant hepatocyte apoptosis, was not seen in long-term stable allografts, primary biliary cirrhosis, cholestasis, paracetamol-induced fulminant hepatic failure, or fulminant hepatic failure of indeterminate origin (non-A, non-B, non-C hepatitis). Bile ducts rarely stained positively, but mononuclear cells present in the post-transplant tissues were frequently positive, showing nuclear or cytoplasmic staining. The presence of cytoplasmic staining suggested that some mononuclear cells had ingested apoptotic DNA from other cellular sources. PCD may thus contribute to the perivenular hepatocyte loss in chronic rejection. The absence of ductular epithelial cell staining suggests that PCD is not involved significantly in the bile duct loss of VBDS. Furthermore, apoptosis of monomuclear cells implies that PCD may be involved in regulating the inflammatory cell infiltration of graft rejection.     

Circumferential cells of the developing Rana catesbeiana lumbar spinal cord

Summary Neural elements in the lumbar enlargement of the developing Rana catesbeiana spinal cord were labelled by placing chips of dessicated horseradish peroxidase (HRP) into various lesions of the spinal cord. Of the elements labelled in the lumbar enlargement, a population of cells circumjacent to the gray matter was seen to be distinct from all others on the basis of their morphology, position and their putative embryonic origin. One cell type not previously described was a large circumferential cell (LCC) with primary processes completely circumscribing the gray matter. The ventral process crosses the midline and ascends or descends in the ventral funiculus. The dorsal primary process was observed to extend to the midline and turn ipsilaterally in a rostro-caudal direction in the dorsal funiculus. LCC's were present at early stages of larval development (stage III, Taylor and Kollros 1946) but could not be labelled in juvenile frogs. LCC's were only observed in the lumbar enlargement and could only be labelled through HRP applications at that level. They receive abundant synaptic input from the ipsilateral lateral funiculus. Possible roles for the LCC in the early function and development of the ranid lumbar spinal cord are discussed.     

Mechanisms of changes to the liver pigmentary component during the annual cycle (activity and hibernation) of Rana esculenta L.

The present study was performed to elucidate the mechanisms responsible for the changes of melanin content/distribution we had previously discovered in the liver parenchyma of Rana esculenta during natural hibernation. Melanomacrophagic component response was analysed using morphocytochemical methods. The results demonstrated that during the prehibernation period (October–November) the melanomacrophages reach the highest proliferative activity (BrdU, PCNA labelling) which is accompanied by an evident melanosynthesis (dopa‐oxidase activity). In contrast, after hibernation, the decrease of liver pigmentation was the consequence of a partial cell loss by apoptotic mechanisms (TUNEL labelling, pyknosis‐karyorhexis) accompanied by a decrease of melanosome content by autophagy and low melanosynthetic activity. On the basis of these findings, there is evidence that liver melanomacrophages represent a metabolically (melanin synthesis/degradation) and cytokinetically (proliferation/death) active cell population during the annual cycle of the frog. The results are also discussed in relation to the functional synergism between hepatocytes and pigment cells in the adaptation to environmental changes.     

Germ cell apoptosis in autoimmune orchitis: involvement of the Fas-FasL system

PROBLEM: The aim of this study was to determine the mechanism of germ cell death in experimental autoimmune orchitis (EAO) and the involvement of the Fas-FasL system in this process. METHOD OF STUDY: The EAO was induced in rats by immunization with testis homogenate and adjuvants. Apoptosis was studied by light microscopy, in situ end labeling of apoptotic DNA and DNA fragmentation techniques. Fas, FasL and caspase 3 expression was detected by immunohistochemistry. RESULTS: In rats with orchitis the number of Fas+ and FasL+ apoptotic germ cells increased from day 50, when the lesion develops, to 150 days, and correlates with the degree of testicular damage. Most spermatocytes expressing Fas were apoptotic. Many Fas+ germ cells were also immunoreactive for FasL. Moreover, these cells also expressed caspase 3. CONCLUSIONS: In rats with EAO germ cell death occurs through an apoptotic mechanism preceding germ cell sloughing. Immunohistochemical data suggest that the Fas-FasL system mediates germ cell apoptosis in an autocrine and/or paracrine way.     

瑞舒伐他汀对大鼠颈动脉球囊损伤后细胞凋亡的影响

目的观察瑞舒伐他汀对大鼠颈动脉球囊损伤后细胞凋亡的影响。方法36只雄性SD大鼠随机分为对照组、损伤组和治疗组,每组12只。损伤组和治疗组分别建立大鼠左侧颈动脉球囊损伤模型,右侧颈动脉未予球囊损伤。治疗组于损伤前3d始连续每天给予瑞舒伐他汀5mg／（kg·d）灌胃,对照组和损伤组予9g／L氯化钠溶液灌胃。术后14d取左侧颈总动脉,进行HE染色和末端脱氧核苷酸转移酶介导的生物素-dUTP缺口标记技术（Terminal deoxynucleotidyl transferase biotin—dUTP nick end labeling,TUNEL）的凋亡检测。结果共30只大鼠成功完成本次实验。①血管损伤14d,可见明显的新生内膜;损伤组和治疗组的内膜面积、内膜／中膜面积的比值较对照组增大（P〈0．05）;与损伤组比较,治疗组内膜／中膜面积的比值减少,管腔面积增加26％（P〈0．05）。②对照组血管偶可见单个散在的凋亡细胞;损伤组凋亡细胞阳性率为（12．3±1．8）％,与对照组比较,差异有统计学意义（P〈0．05）;治疗组凋亡细胞数目增多,凋亡细胞阳性率达（26．8±3．2）％,与损伤组比较,差异有统计学意义（P〈0．05）。凋亡细胞主要位于新生内膜。结论瑞舒伐他汀可抑制大鼠颈动脉球囊损伤后的内膜增生,可促进大鼠颈动脉球囊损伤后的细胞凋亡。瑞舒伐他汀促进细胞凋亡的作用可能与其抑制内膜增生有关。     

Apoptosis in cavitation of middle ear space

Mesenchyme cells surround early ossicles in the developing middle ear, then are replaced by space that is created by what has been described as an expansion of the pharyngeal pouch. Cell death has not been considered important in cavitation of chick middle ear (Jaskoll and Maderson [1978] Anat. Rec., 190:177–200), but an uncharacterized form of cell death has been reported to play a major role in cavitation of mouse middle ear (Jaskoll [1977] PhD thesis, CUNY). We investigated whether this uncharacterized cell death is the non-random form known as apoptosis. We examined the middle ear cavitation process using an in situ immunomarker for apoptosis. CBy RF mice during prenatal days 15–20 and postnatal days 1–3 and chick embryos representing HH stages 33–38 were investigated. Apoptotic cells were marked in mouse postnatal day 1. No indication of apoptosis was present in other prenatal and postnatal days of development included in this study, although morphology showed that cavitation proceeds over several perinatal days in the mouse. Apoptosis was not marked in the chick middle ear. Previously observed cell death in murine middle ear is the non-random form of cell death known as apoptosis. Cell death has not been reported in avian middle ear, and lack of apoptotic marker supports those observations. The limited occurrence of apoptosis in mice and apparent absence of apoptosis in chicks suggest that several mechanisms contribute to cavitation of vertebrate middle ear space. Anat. Rec. 251:286–289, 1998. © 1998 Wiley-Liss, Inc.     

Immunohistochemical markers of carcinoma in situ of the testis also expressed in normal infantile germ cells

Carcinoma in situ of the testis is an intratubular, pre-invasive lesion preceding germ cell tumour. In adult men, carcinoma in situ cells differ in several aspects from normal germ cells. For example, placental-like alkaline phosphatase and/or the epitopes for the monoclonal antibodies M2A, 43-9F and TRA-1–60 are not seen in normal germ cells, whereas their presence is considered a specific sign of carcinoma in situ . As it is known that placental-like alkaline phosphatase and the epitope for TRA-1–60 are expressed in normal fetal germ cells it is possible that the markers could appear in normal infantile germ cells in a period after birth before they lose their expression. In children, carcinoma in situ cells may be difficult to identify morphologically and the use of the markers could be of great value. However, little information is available on the expression of the markers of adult carcinoma in situ in normal infantile germ cells. We investigated gonads from 66 boys less than 15 years old who died suddenly. Their deaths were unrelated to testicular disease. Immunohistochemical staining with anti-placental-like alkaline phosphatase antibody and monoclonal antibodies TRA-1–60 and 43–9F were performed. We found that these markers were expressed in some normal infantile germ cells until the age of 1 year. Therefore, these markers are not suitable for diagnosis of carcinoma in situ during the early postnatal period of life. Furthermore, our findings of placental-like alkaline phosphatase and the epitope for TRA-1–60 in normal germ cells before birth indicate that the markers of adult carcinoma in situ cells are of embryonic origin. This is in accordance with the hypothesis that carcinoma in situ cells are fetal germ cells malignantly transformed during fetal life, although re-expression of the antigens could provide an alternative explanation.     

Apoptosis in the cortex of the developing mouse kidney

Published levels of apoptosis in developing rat kidney (approximately 2.5%) seem large for a tissue with no obvious need for continual cell death. This paper examines the levels and patterns of apoptosis and mitosis in the cortical region of the developing metanephros of the mouse, the standard mammalian model embryo. Using confocal microscopy on specimens stained with propidium iodide to highlight nuclear morphology, optical sections of wholemount kidneys to a depth of approximately 50 microm were analysed and mitotic, apoptotic and interphase nuclei counted in the various compartments. Of the approximately 200 000 cells examined over E11.5-16.5, 2-3% were mitotic, confirming observations based on cryosections; the mitotic index peaked at E14.5, dropping to approximately 0.5% by P14. The mean apoptotic index during this period was 0.28%; this figure from wholemounts was approximately 10% of that earlier reported in cryosectioned rat kidneys. One possible explanation for the difference is that cryosectioning turns out to create small nuclear fragments that can stain strongly with propidium. Such fragments are not seen in wholemounts and do not stain with TUNEL. Wholemount mouse E11.5 tails and E16.5 lungs were also analysed and both their mitotic and their apoptotic indexes were similar to those in wholemount developing kidneys. These results show that the level of apoptosis in wholemount embryonic mouse kidney cortex is far less than previously reported in cryosectioned rat embryonic kidneys, and typical of that in other mouse embryonic tissues whose development seems not to require apoptosis.     

An ultrastructural and morphometric analysis of the Sertoli cell during the spermatogenic cycle of the rat

Summary The ultrastructure of Sertoli cells from selected stages of the spermatogenic cycle was assessed by morphometric analysis which showed significant changes in the morphological features of Sertoli cell cytoplasm at the commencement of the cycle (stage II) compared to the middle (stages VII-VIII) and the completion of the cycle (stages IX-XIV). Total volume and surface area of organelles (rough and smooth endoplasmic reticulum (ER), lysosomes, mitochondria and Golgi) exhibited stage-dependent and cyclic variations as did the total surface area of Sertoli cell plasma membrane. Polarization of cytoplasmic organelles to basal or columnar regions of the Sertoli cell, exhibited particularly by the Golgi, rough ER and lysosomes also showed marked cyclic fluctuations during the spermatogenic cycle. Rough and smooth ER exhibited the most dramatic stage-dependent changes in total volume and surface area the former being respectively largest and smallest in stages VII-VIII and XIII-XIV, the latter organelle presenting the reverse pattern in these two groups of stages. Similar stage-dependent alterations of lysosome volume and surface area were also noted, being maximal during stages XIII-XIV-II and reaching a nadir at stage VIII. Although the functional role of most Sertoli cell organelles and inclusions remain largely unknown, the present study suggests that the cyclic and stage-dependent variations in ultrastructure probably reflect major changes in Sertoli cell function necessary for the regulation of the spermatogenic cycle.     

A light microscopic and morphometric analysis of the Sertoli cell during the spermatogenic cycle of the rat

Summary Testes from 8 adult rats were perfusion-fixed with buffered glutaraldehyde and semi-thin sections of the seminiferous epithelium at all stages of the spermatogenic cycle were subjected to morphometric analysis at the light microscope level. Methods are presented to derive the volume occupied by the Sertoli cells within the total volume of the seminiferous epithelium at each stage of the cycle for a single testis. The total number of Sertoli cells present in each stage for the whole testis was calculated from a measurement of Sertoli cell numerical density and the total volume of the seminiferous tubule in the testis at each stage of the cycle. Average volume of a single Sertoli cell for each stage was derived by dividing the first set of data by the latter data. Average Sertoli cell volume exhibited a cyclic variation in relation to the stages of the spermatogenic cycle. Sertoli cells were smallest during stages VI–VIII (5300–5500 m³) increased to maximum volume during stages XII–XIV (7700–8000 m³) and thereafter during stages I–V, gradually contracted in volume to complete the cycle. Stage-dependent cyclic variations in Sertoli cell volume offers evidence that the morphology of the Sertoli cell undergoes structural modifications to accommodate changes in the shape and volume of the developing germ cells. Furthermore these volume changes implicate the Sertoli cells in cyclic metabolic, absorptive and secretory functions which possibly direct the maturation of germ cells during the spermatogenic cycle.     

Altered expression of p27Kip1‐interacting cell‐cycle regulators in the adult testicular germ cell tumors: potential role in tumor development and histological progression

We examined the potential role of cell‐cycle dysregulation in the development and histological progression of adult testicular germ cell tumors (TGCTs). Expressions of p27^Kip1‐interacting cell‐cycle regulators (down‐regulation of p27^Kip1 and overexpression of Skp2, Cks1, cyclin A, and cyclin E) and Ki‐67 labeling index (LI) were immunohistochemically examined in histological components of 50 intratubular germ cell neoplasms, unclassified (IGCNUs); 74 seminomas; and 25 embryonal carcinomas, identified from 88 patients. Altered expression of p27^Kip1, Skp2, Cks1, cyclin A, and cyclin E was observed in 20%, 12%, 16%, 10%, and 24% of IGCNUs; 26%, 36%, 27%, 89%, and 23% of seminomas; and 48%, 68%, 56%, 100%, and 60% of embryonal carcinomas, respectively. A significant difference in the frequency of Skp2 and cyclin A overexpression was observed between IGCNUs and seminomas. Significantly more frequent alterations of Skp2, Cks1, and cyclin E and p27^Kip1 were detected in embryonal carcinomas than in seminomas. Alterations of all cell‐cycle regulators were significantly more frequent in embryonal carcinomas than in IGCNUs. The mean Ki‐67 LI significantly increased from IGCNU (21.2%) through seminoma (34.7%) to embryonal carcinoma (54.2%). These results suggest that alterations of the p27^Kip1‐interacting cell‐cycle regulators are common in TGCTs and may be involved in their histological progression.     

Atypical germ cells of the testis

Summary It is uncertain whether the so called intratubular atypical germ cells (carcinoma in situ cells) demonstrable in the testicular tissue around different germ cell tumors and in testicular biopsies of patients with impaired fertility are identical with regard to their morphology and further development. Thus atypical germ cells of 18 patients with testicular germ cell tumors and of 3 patients with atypical germ cells in testicular biopsies without tumor were studied by electron microscopy and/or by immunohistochemistry. The atypical germ cells show characteristic alterations distinguishing them from normal germ cells, especially spermatogonia. However, there are no differences between atypical germ cells in the above mentioned groups. Immunohistochemical reactions are negative with anti-alpha-fetoprotein and anti-beta-human-chorionic-gonadotropin, but 6 of the 15 cases are positive with antiferritin. However, this positive reaction occurs in cases in different diagnostic groups. Atypical germ cells of the different groups cannot be distinguished by electron microscopy or immunohistochemical methods, but further investigations vestigations, including cell cultures, may provide more information.