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1

Generation of organized germ layers from a single mouse embryonic stem cell  

PubMed Central

Mammalian inner cell mass cells undergo lineage-specific differentiation into germ layers of endoderm, mesoderm and ectoderm during gastrulation. It has been a long-standing challenge in developmental biology to replicate these organized germ layer patterns in culture. Here we present a method of generating organized germ layers from a single mouse embryonic stem cell cultured in a soft fibrin matrix. Spatial organization of germ layers is regulated by cortical tension of the colony, matrix dimensionality and softness, and cell–cell adhesion. Remarkably, anchorage of the embryoid colony from the 3D matrix to collagen-1-coated 2D substrates of ~1?kPa results in self-organization of all three germ layers: ectoderm on the outside layer, mesoderm in the middle and endoderm at the centre of the colony, reminiscent of generalized gastrulating chordate embryos. These results suggest that mechanical forces via cell–matrix and cell–cell interactions are crucial in spatial organization of germ layers during mammalian gastrulation. This new in vitro method could be used to gain insights on the mechanisms responsible for the regulation of germ layer formation. PMID:24873804

Poh, Yeh-Chuin; Chen, Junwei; Hong, Ying; Yi, Haiying; Zhang, Shuang; Chen, Junjian; Wu, Douglas C.; Wang, Lili; Jia, Qiong; Singh, Rishi; Yao, Wenting; Tan, Youhua; Tajik, Arash; Tanaka, Tetsuya S.; Wang, Ning

2014-01-01

2

Spatiotemporal transcriptomics reveals the evolutionary history of the endoderm germ layer.  

PubMed

The concept of germ layers has been one of the foremost organizing principles in developmental biology, classification, systematics and evolution for 150 years (refs 1 - 3). Of the three germ layers, the mesoderm is found in bilaterian animals but is absent in species in the phyla Cnidaria and Ctenophora, which has been taken as evidence that the mesoderm was the final germ layer to evolve. The origin of the ectoderm and endoderm germ layers, however, remains unclear, with models supporting the antecedence of each as well as a simultaneous origin. Here we determine the temporal and spatial components of gene expression spanning embryonic development for all Caenorhabditis elegans genes and use it to determine the evolutionary ages of the germ layers. The gene expression program of the mesoderm is induced after those of the ectoderm and endoderm, thus making it the last germ layer both to evolve and to develop. Strikingly, the C. elegans endoderm and ectoderm expression programs do not co-induce; rather the endoderm activates earlier, and this is also observed in the expression of endoderm orthologues during the embryology of the frog Xenopus tropicalis, the sea anemone Nematostella vectensis and the sponge Amphimedon queenslandica. Querying the phylogenetic ages of specifically expressed genes reveals that the endoderm comprises older genes. Taken together, we propose that the endoderm program dates back to the origin of multicellularity, whereas the ectoderm originated as a secondary germ layer freed from ancestral feeding functions. PMID:25487147

Hashimshony, Tamar; Feder, Martin; Levin, Michal; Hall, Brian K; Yanai, Itai

2015-03-12

3

Functions of Huntingtin in Germ Layer Specification and Organogenesis  

PubMed Central

Huntington’s disease (HD) is a neurodegenerative disease caused by abnormal polyglutamine expansion in the huntingtin protein (Htt). Although both Htt and the HD pathogenic mutation (mHtt) are implicated in early developmental events, their individual involvement has not been adequately explored. In order to better define the developmental functions and pathological consequences of the normal and mutant proteins, respectively, we employed embryonic stem cell (ESC) expansion, differentiation and induction experiments using huntingtin knock-out (KO) and mutant huntingtin knock-in (Q111) mouse ESC lines. In KO ESCs, we observed impairments in the spontaneous specification and survival of ectodermal and mesodermal lineages during embryoid body formation and under inductive conditions using retinoic acid and Wnt3A, respectively. Ablation of BAX improves cell survival, but failed to correct defects in germ layer specification. In addition, we observed ensuing impairments in the specification and maturation of neural, hepatic, pancreatic and cardiomyocyte lineages. These developmental deficits occurred in concert with alterations in Notch, Hes1 and STAT3 signaling pathways. Moreover, in Q111 ESCs, we observed differential developmental stage-specific alterations in lineage specification and maturation. We also observed changes in Notch/STAT3 expression and activation. Our observations underscore essential roles of Htt in the specification of ectoderm, endoderm and mesoderm, in the specification of neural and non-neural organ-specific lineages, as well as cell survival during early embryogenesis. Remarkably, these developmental events are differentially deregulated by mHtt, raising the possibility that HD-associated early developmental impairments may contribute not only to region-specific neurodegeneration, but also to non-neural co-morbidities. PMID:23967334

Nguyen, Giang D.; Molero, Aldrin E.; Gokhan, Solen; Mehler, Mark F.

2013-01-01

4

Differences in Transcription Patterns between Induced Pluripotent Stem Cells Produced from the Same Germ Layer Are Erased upon Differentiation  

PubMed Central

Little is known about differences between induced pluripotent stem cells produced from tissues originating from the same germ layer. We have generated human myoblast-derived iPS cells by retroviral transduction of human primary myoblasts with the OCT3/4, SOX2, KLF4 and MYC coding sequences and compared them to iPS produced from human primary fibroblasts. When cultivated in vitro, these iPS cells proved similar to human embryonic stem cells in terms of morphology, expression of embryonic stemness markers and gene promoter methylation patterns. Embryonic bodies were derived that expressed endodermal, mesodermal as well as ectodermal markers. A comparative analysis of transcription patterns revealed significant differences in the gene expression pattern between myoblast- and fibroblast-derived iPS cells. However, these differences were reduced in the mesenchymal stem cells derived from the two iPS cell types were compared. PMID:23326377

Pirozhkova, Iryna; Robert, Thomas; Guégan, Justine; Bilhou-Nabera, Chrystèle; Busato, Florence; Tost, Jörg; Carnac, Gilles; Laoudj-Chenivesse, Dalila; Lipinski, Marc; Vassetzky, Yegor

2013-01-01

5

Germ layer formation during Xenopus embryogenesis: the balance between pluripotency and differentiation.  

PubMed

The African clawed frog, Xenopus laevis, has long been a model animal for the studies in the fields of animal cloning, developmental biology, biochemistry, cell biology, and physiology. With the aid of Xenopus, major molecular mechanisms that are involved in embryonic development have been understood. Germ layer formation is the first event of embryonic cellular differentiation, which is induced by a few key maternal factors and subsequently by zygotic signals. Meanwhile, another type of signals, the pluripotency factors in ES cells, which maintain the undifferentiated state, are also present during early embryonic cells. In this review, the functions of the pluripotency factors during Xenopus germ layer formation and the regulatory relationship between the signals that promote differentiation and pluripotency factors are discussed. PMID:25862657

Cao, Ying

2015-04-01

6

Effects of Wheat Germ Extract on the Severity and Systemic Symptoms of Primary Dysmenorrhea: A Randomized Controlled Clinical Trial  

PubMed Central

Background: Primary dysmenorrhea is one of the most common disorders in women and the main cause of absenteeism from work and school. Objectives: Considering the anti-inflammatory properties of wheat germ, the present study examined the effects of wheat germ extract on the severity and systemic symptoms of primary dysmenorrhea. Patients and Methods: This triple-blinded clinical trial was performed on 80 employed women in hospitals affiliated with Hamadan University of Medical Sciences (Hamadan, IR Iran). Subjects were allocated to two groups of 45 patients. Three 400-mg capsules of wheat germ extract or placebo were used daily? between the 16th day of the menstrual cycle to the fifth day of the next menstrual cycle for two consecutive months. Pain intensity was measured by a visual analogue scale thrice a day and a four-point verbal rating scale was employed to assess systemic symptoms. Results: Pain severity decreased only in the wheat germ extract group (P < 0.001) and there was no statistically significant change in the placebo group. In the wheat germ extract group, the pain severity decreased from 4.701 at baseline to 1.120 at the second cycle. The reduction in total scores of systemic symptoms of dysmenorrhea was statistically significant only in the wheat germ extract group (P < 0.001) and there was not a statistically significant change in the placebo group. It revealed statistically significant differences in systemic symptoms associated with dysmenorrhea including fatigue, headache, and mood swings in experimental group. Conclusions: Wheat germ extract seems to be an effective treatment for dysmenorrhea and its systemic symptoms, probably because of its anti-inflammatory effects. PMID:25389490

Atallahi, Maryam; Amir Ali Akbari, Sedigheh; Mojab, Faraz; Alavi Majd, Hamid

2014-01-01

7

Primary mixed germ cell tumor of the liver with sarcomatous components  

PubMed Central

Germ cell tumor (GCT) of the liver is extremely rare. Here, we describe a case of hepatic mixed GCT with significant sarcomatous components and elevated serum ?-fetoprotein (AFP) in a 34-year-old man. Histopathologically, the tumor was composed of two GCTs components: yolk sac tumor and immature teratoma. The predominant components of immature teratoma consisted of several types of tissue that represented different germinal layers (endoderm, mesoderm and ectoderm) and showed varying degrees of differentiation with significant sarcomatous components. The yolk sac component showed positivity for AFP and cytokeratin (AE1/AE3). The immature teratoma components showed positivity for varying differentiation markers. Interphase cytogenetic analysis revealed that the yolk sac tumor and immature teratoma were positive for i(12p) and 12p over-representation. In particular, the rhabdomyoblastic components also showed typical i(12p) and 12p overrepresentation. This suggested that sarcomatous components may be associated with dedifferentiation or malignant transformation of certain mesenchymal components within teratoma. PMID:20128038

Xu, Ai-Min; Gong, Shao-Juan; Song, Wei-Hua; Li, Xiao-Wei; Pan, Chun-Hua; Zhu, Jun-Jun; Wu, Meng-Chao

2010-01-01

8

Symmetry breaking, germ layer specification and axial organisation in aggregates of mouse embryonic stem cells  

PubMed Central

Mouse embryonic stem cells (mESCs) are clonal populations derived from preimplantation mouse embryos that can be propagated in vitro and, when placed into blastocysts, contribute to all tissues of the embryo and integrate into the normal morphogenetic processes, i.e. they are pluripotent. However, although they can be steered to differentiate in vitro into all cell types of the organism, they cannot organise themselves into structures that resemble embryos. When aggregated into embryoid bodies they develop disorganised masses of different cell types with little spatial coherence. An exception to this rule is the emergence of retinas and anterior cortex-like structures under minimal culture conditions. These structures emerge from the cultures without any axial organisation. Here, we report that small aggregates of mESCs, of about 300 cells, self-organise into polarised structures that exhibit collective behaviours reminiscent of those that cells exhibit in early mouse embryos, including symmetry breaking, axial organisation, germ layer specification and cell behaviour, as well as axis elongation. The responses are signal specific and uncouple processes that in the embryo are tightly associated, such as specification of the anteroposterior axis and anterior neural development, or endoderm specification and axial elongation. We discuss the meaning and implications of these observations and the potential uses of these structures which, because of their behaviour, we suggest to call ‘gastruloids’. PMID:25371360

van den Brink, Susanne C.; Baillie-Johnson, Peter; Balayo, Tina; Hadjantonakis, Anna-Katerina; Nowotschin, Sonja; Turner, David A.; Martinez Arias, Alfonso

2014-01-01

9

Symmetry breaking, germ layer specification and axial organisation in aggregates of mouse embryonic stem cells.  

PubMed

Mouse embryonic stem cells (mESCs) are clonal populations derived from preimplantation mouse embryos that can be propagated in vitro and, when placed into blastocysts, contribute to all tissues of the embryo and integrate into the normal morphogenetic processes, i.e. they are pluripotent. However, although they can be steered to differentiate in vitro into all cell types of the organism, they cannot organise themselves into structures that resemble embryos. When aggregated into embryoid bodies they develop disorganised masses of different cell types with little spatial coherence. An exception to this rule is the emergence of retinas and anterior cortex-like structures under minimal culture conditions. These structures emerge from the cultures without any axial organisation. Here, we report that small aggregates of mESCs, of about 300 cells, self-organise into polarised structures that exhibit collective behaviours reminiscent of those that cells exhibit in early mouse embryos, including symmetry breaking, axial organisation, germ layer specification and cell behaviour, as well as axis elongation. The responses are signal specific and uncouple processes that in the embryo are tightly associated, such as specification of the anteroposterior axis and anterior neural development, or endoderm specification and axial elongation. We discuss the meaning and implications of these observations and the potential uses of these structures which, because of their behaviour, we suggest to call 'gastruloids'. PMID:25371360

van den Brink, Susanne C; Baillie-Johnson, Peter; Balayo, Tina; Hadjantonakis, Anna-Katerina; Nowotschin, Sonja; Turner, David A; Martinez Arias, Alfonso

2014-11-01

10

An ancient role for nuclear beta-catenin in the evolution of axial polarity and germ layer segregation  

NASA Technical Reports Server (NTRS)

The human oncogene beta-catenin is a bifunctional protein with critical roles in both cell adhesion and transcriptional regulation in the Wnt pathway. Wnt/beta-catenin signalling has been implicated in developmental processes as diverse as elaboration of embryonic polarity, formation of germ layers, neural patterning, spindle orientation and gap junction communication, but the ancestral function of beta-catenin remains unclear. In many animal embryos, activation of beta-catenin signalling occurs in blastomeres that mark the site of gastrulation and endomesoderm formation, raising the possibility that asymmetric activation of beta-catenin signalling specified embryonic polarity and segregated germ layers in the common ancestor of bilaterally symmetrical animals. To test whether nuclear translocation of beta-catenin is involved in axial identity and/or germ layer formation in 'pre-bilaterians', we examined the in vivo distribution, stability and function of beta-catenin protein in embryos of the sea anemone Nematostella vectensis (Cnidaria, Anthozoa). Here we show that N. vectensis beta-catenin is differentially stabilized along the oral-aboral axis, translocated into nuclei in cells at the site of gastrulation and used to specify entoderm, indicating an evolutionarily ancient role for this protein in early pattern formation.

Wikramanayake, Athula H.; Hong, Melanie; Lee, Patricia N.; Pang, Kevin; Byrum, Christine A.; Bince, Joanna M.; Xu, Ronghui; Martindale, Mark Q.

2003-01-01

11

Lin28 proteins are required for germ layer specification in Xenopus.  

PubMed

Lin28 family proteins share a unique structure, with both zinc knuckle and cold shock RNA-binding domains, and were originally identified as regulators of developmental timing in Caenorhabditis elegans. They have since been implicated as regulators of pluripotency in mammalian stem cells in culture. Using Xenopus tropicalis, we have undertaken the first analysis of the effects on the early development of a vertebrate embryo resulting from global inhibition of the Lin28 family. The Xenopus genome contains two Lin28-related genes, lin28a and lin28b. lin28a is expressed zygotically, whereas lin28b is expressed both zygotically and maternally. Both lin28a and lin28b are expressed in pluripotent cells of the Xenopus embryo and are enriched in cells that respond to mesoderm-inducing signals. The development of axial and paraxial mesoderm is severely abnormal in lin28 knockdown (morphant) embryos. In culture, the ability of pluripotent cells from the embryo to respond to the FGF and activin/nodal-like mesoderm-inducing pathways is compromised following inhibition of lin28 function. Furthermore, there are complex effects on the temporal regulation of, and the responses to, mesoderm-inducing signals in lin28 morphant embryos. We provide evidence that Xenopus lin28 proteins play a key role in choreographing the responses of pluripotent cells in the early embryo to the signals that regulate germ layer specification, and that this early function is probably independent of the recognised role of Lin28 proteins in negatively regulating let-7 miRNA biogenesis. PMID:23344711

Faas, Laura; Warrander, Fiona C; Maguire, Richard; Ramsbottom, Simon A; Quinn, Diana; Genever, Paul; Isaacs, Harry V

2013-03-01

12

Variation in the dorsal gradient distribution is a source for modified scaling of germ layers in Drosophila.  

PubMed

Specification of germ layers along the dorsoventral axis by morphogenetic gradients is an ideal model to study scaling properties of gradients and cell fate changes during evolution. Classical anatomical studies in divergent insects (e.g., flies and grasshoppers) revealed that the neuroectodermal size is conserved and originates similar numbers of neuroblasts of homologous identity. In contrast, mesodermal domains vary significantly in closely related Drosophila species. To further investigate the underlying mechanisms of scaling of germ layers across Drosophila species, we quantified the Dorsal (Dl)/NF-?B gradient, the main morphogenetic gradient that initiates separation of the mesoderm, neuroectoderm, and ectoderm. We discovered a variable range of Toll activation across species and found that Dl activates mesodermal genes at the same threshold levels in melanogaster sibling species. We also show that the Dl gradient distribution can be modulated by nuclear size and packing densities. We propose that variation in mesodermal size occurs at a fast evolutionary rate and is an important mechanism to define the ventral boundary of the neuroectoderm. PMID:23583556

Chahda, Juan Sebastian; Sousa-Neves, Rui; Mizutani, Claudia Mieko

2013-04-22

13

Human Embryonic Stem Cells and Germ Cell Development  

Microsoft Academic Search

\\u000a Embryonic stem cells (ESCs) are derived from the inner cell mass (ICM) of blastocysts and are characterized by the ability\\u000a to differentiate into the three primary germ layers. Evidence shows, however, that the cells of the ICM and derived ESCs are\\u000a not identical. Expression of early germ cell–specific markers in undifferentiated ESCs and the ability of ESCs to differentiate\\u000a into

Nina J. Kossack; Joerg Gromoll; Renee A. Reijo Pera

14

Glo Germ  

NSDL National Science Digital Library

This experiment helped a group of friends actually see how germs are spread. They were able to see how following health tips (like sneezing into your elbow instead of your hand) helped limit the amount of germs spread to others.

Dragonfly TV

15

Fighting Germs  

MedlinePLUS

Home Body Fighting germs Fighting germs It may sound kind of disgusting, but germs are everywhere. They are so small that you can’t see them, but they can have a big effect on your body. There are four different types ...

16

Transcriptional profiling of endogenous germ layer precursor cells identifies dusp4 as an essential gene in zebrafish endoderm specification.  

PubMed

A major goal for developmental biologists is to define the behaviors and molecular contents of differentiating cells. We have devised a strategy for isolating cells from diverse embryonic regions and stages in the zebrafish, using computer-guided laser photoconversion of injected Kaede protein and flow cytometry. This strategy enabled us to perform a genome-wide transcriptome comparison of germ layer precursor cells. Mesendoderm and ectoderm precursors cells isolated by this method differentiated appropriately in transplantation assays. Microarray analysis of these cells reidentified known genes at least as efficiently as previously reported strategies that relied on artificial mesendoderm activation or inhibition. We also identified a large set of uncharacterized mesendoderm-enriched genes as well as ectoderm-enriched genes. Loss-of-function studies revealed that one of these genes, the MAP kinase inhibitor dusp4, is essential for early development. Embryos injected with antisense morpholino oligonucleotides that targeted Dusp4 displayed necrosis of head tissues. Marker analysis during late gastrulation revealed a specific loss of sox17, but not of other endoderm markers, and analysis at later stages revealed a loss of foregut and pancreatic endoderm. This specific loss of sox17 establishes a new class of endoderm specification defect. PMID:18719100

Brown, Jamie L; Snir, Mirit; Noushmehr, Houtan; Kirby, Martha; Hong, Sung-Kook; Elkahloun, Abdel G; Feldman, Benjamin

2008-08-26

17

Germ Tag  

NSDL National Science Digital Library

In this version of tag, a large group of learners model how the body fights infection. Learners act as germs, as lymphocytes, and as the body's cells threatened by germs. After playing one round, subsequent rounds can use different numbers of germs and/or lymphocytes to see how the infection rate is changed. When learners set up a free account at Kinetic City, they can answer bonus questions at the end of the activity as a quick assessment. They can also keep track of their progress in all of the Kinetic City activities, and compare their progress to other participants worldwide.

American Association for the Advancement of Science

2009-01-01

18

Non-primary layering in some Adirondack orthogneisses  

SciTech Connect

Metamorphic, as opposed to primary, layering has been shown to be important in many tectonites. Within orthogneisses additional types of non-primary layering are common and have important genetic implications. Here the authors cite three Adirondack examples. (1) Hyde School Gneiss of the Adirondack Lowlands contains semi-continuous layers of foliated amphibolite arranged parallel to contacts and early foliation and disrupted by pegmatitic, alaskitic, and tonalitic host rock. Layering appears to be the result of penetration of amphibolite by granitoid magma first along extensional fractures and then parallel to foliation. Intrusion is envisaged to take place in active shear zones initially occupied by foliated amphibolite that is subsequently penetrated parallel to foliation by granitoids. (2) South of Elizabethtown foliated, isoclinally folded gabbroic anorthosite is well layered with garnetiferous amphibolite, quartz-feldspar gneiss, and calcsilicate. Because of rock composition, the layering cannot be due to metavolcanic sequences nor can disruption be attributed to partial melting. A satisfactory interpretation is that gabbroic anorthosite intruded mafic and carbonate-rich rocks in lit-par-lit fashion. (3) North of Speculator a garnetiferous amphibolite/gabbro has been intruded by granite now containing xenoliths, some with ophitic opx. Much of the layering in the granite consists of clots of plagioclase, garnet, pyroxene (chloritized) arranged in parallel. These are interpreted as small xenoliths of garnetiferous amphibolite/gabbro entrained into the granitic magma and strung out in the direction of flow. These examples provide further evidence that layering can develop during magmatic emplacement and need not represent primary stratification. Assignment of a primary origin to such layering necessarily results in misinterpretation of geologic history.

Levy, R.; McLelland, J.; Ritter, A. (Colgate Univ., Hamilton, NY (United States). Geology Dept.)

1993-03-01

19

Trainee Primary Teachers' Ideas about the Ozone Layer.  

ERIC Educational Resources Information Center

Survey results reveal trainee primary teachers are well informed about the nature and location of the ozone layer and appreciated that it screens the earth from ultraviolet (UV) rays, although some thought that it protects the earth from acid rain. Identifies themes in students' thinking and groups of students with different concepts. (LZ)

Boyes, Edward; And Others

1995-01-01

20

In vitro male germ cell cultures of zebrafish.  

PubMed

Transgenic modification of sperm before fertilization has the advantages of a much shorter timeline for the production of transgenic animals. A culture system using primary cultures of zebrafish male germ cells, in which the differentiation of spermatogonia to functional sperm can occur in vitro, allows us to introduce foreign DNA into the cultured sperm and to produce transgenics from the sperm. This chapter describes methods for the co-culture of male germ cells and a Sertoli cell feeder layer and the introduction of foreign DNA with retroviruses. This male germ cell culture system should prove useful not only in producing genetically modified sperm, but also in analyzing the regulatory function of Sertoli cells for spermatogenesis in vertebrates. PMID:16828310

Sakai, Noriyoshi

2006-07-01

21

Germ Cell Differentiation from Pluripotent Cells  

PubMed Central

Infertility is a medical condition with an increasing impact in Western societies with causes linked to toxins, genetics, and aging (primarily delay of motherhood). Within the different pathologies that can lead to infertility, poor quality or reduced quantity of gametes plays an important role. Gamete donation and therefore demand on donated sperm and eggs in fertility clinics is increasing. It is hoped that a better understanding of the conditions related to poor gamete quality may allow scientists to design rational treatments. However, to date, relatively little is known about human germ cell development in large part due to the inaccessibility of human development to molecular genetic analysis. It is hoped that pluripotent human embryonic stem cells and induced pluripotent stem cells may provide an accessible in vitro model to study germline development; these cells are able to differentiate to cells of all three primary embryonic germ layers, as well as to germ cells in vitro. We review the state of the art in germline differentiation from pluripotent stem cells. PMID:23329632

Medrano, Jose V.; Pera, Renee A. Reijo; Simón, Carlos

2014-01-01

22

Morphological changes and germ layer formation in the porcine embryos from days 7-13 of development.  

PubMed

Morphogenesis and identification of embryonic differentiation in porcine embryos are crucial issues for developmental biology and laboratory animal science. The current paper presents a study on the asynchronous development of hatched porcine embryos from days 7 to 13 post-insemination. Examination of semi-thin sections of the hypoblast showed that it had characteristics similar to those of the mouse anterior visceral endoderm during embryonic disc formation. Also, a cavity appeared in the epiblast, which was similar to a mouse proamniotic cavity. With the gradual disappearance of Rauber's layer, the cavity opened and contacted the external environment directly, all of which formed the embryonic disc. To confirm the differentiation characteristics, we performed immunohistochemical analyses and showed that GATA6 was detected clearly in parietal endoderm cells during embryonic disc establishment. OCT4 was expressed in the inner cell mass (ICM) and trophoblast of hatched blastocysts and in the epiblast during formation of the embryonic disc. However, OCT4 showed comparatively decreased expression in the posterior embryonic disc, primitive streak and migrating cells. SOX2 was present in the ICM and epiblast. Therefore, both SOX2 and OCT4 can be used as markers of pluripotent cells in the porcine embryonic disc. At the start of gastrulation, staining revealed VIMENTIN in the posterior of the embryonic disc, primitive streak and in migrating cells that underlay the embryonic disc and was also expressed in epiblast cells located in the anterior primitive streak. Together with serial sections of embryos stained by whole mount immunohistochemistry, the mesoderm differentiation pattern was shown as an ingression movement that took place at the posterior of the embryonic disc and with bilateral migration along the embryonic disc borders. PMID:24229742

Sun, Ruizhen; Lei, Lei; Liu, Shichao; Xue, Binghua; Wang, Jianyu; Wang, Jiaqiang; Shen, Jingling; Duan, Lian; Shen, Xinghui; Cong, Yimei; Gu, Yanli; Hu, Kui; Jin, Lianhong; Liu, Zhong-Hua

2015-04-01

23

Imaging of testicular germ cell tumours  

PubMed Central

In testicular germ cell tumour (GCT), imaging plays a central role in assessment of tumour bulk, sites of metastases, monitoring response to therapy, surgical planning and accurate assessment of disease at relapse. The primary modality used for imaging patients with GCT is computed tomography (CT) but plain film radiography, ultrasound, magnetic resonance imaging (MRI) and positron emission tomography (PET) may all have roles to play. This article reviews the role of imaging of testicular germ cell tumours. PMID:16966068

Dalal, P U; Sohaib, S A; Huddart, R

2006-01-01

24

Influence of flow properties on a structure of a mineral wool primary layer  

SciTech Connect

Mineral wool primary layer formation is influenced by the aerodynamic characteristics of the blow-away airflow and the secondary surrounding airflow. The distribution of mineral wool fibres in the primary layer was determined experimentally using a computer-aided visualization method. The flow properties in the region where the primary layer is formed were analysed. Numerical simulations with experiment-based boundary conditions were performed. The numerically obtained profile of mineral wool thickness at the collection chamber outlet agreed with the results of the experiment. Presented numerical model confirms that the forming of the primary layer is significantly dependent on local aerodynamic characteristic of the airflow in the collection chamber. Interaction between the local anomalies on the forming layer and the corresponding aerodynamic effects in the surrounding region was also analysed. (author)

Bajcar, Tom; Blagojevic, Bogdan; Sirok, Brane; Dular, Matevz [Faculty of Mechanical Engineering, University of Ljubljana, Askerceva 6, SI - 1000 Ljubljana (Slovenia)

2007-11-15

25

Male germ cell transplantation.  

PubMed

Transplantation of male germ line stem cells from a donor animal to the testes of an infertile recipient was first described in 1994. Donor germ cells colonize the recipient's testis and produce donor-derived sperm, such that the recipient male can distribute the genetic material of the germ cell donor. Germ cell transplantation represents a functional reconstitution assay for male germ line stem cells and as such has vastly increased our ability to study the biology of stem cells in the testis and define phenotypes of infertility. First developed in rodents, the technique has now been used in a number of animal species, including domestic mammals, chicken and fish. There are three major applications for this technology in animals: first, to study fundamental aspects of male germ line stem cell biology and male fertility; second, to preserve the reproductive potential of genetically valuable individuals by male germ cell transplantation within or between species; third, to produce transgenic sperm by genetic manipulation of isolated germ line stem cells and subsequent transplantation. Transgenesis through the male germ line has tremendous potential in species in which embryonic stem cells are not available and somatic cell nuclear transfer has limited success. Therefore, transplantation of male germ cells is a uniquely valuable approach for the study, preservation and manipulation of male fertility in animals. PMID:18638137

Dobrinski, I

2008-07-01

26

Testicular Germ Cell Cancer  

Cancer.gov

More than 90 percent of testicular cancer start in the germ cells, which are cells in the testicles and develop into sperm. This type of cancer is known as testicular germ cell cancer. Testicular germ cell cancer can be classified as either seminomas or nonseminomas, whose cells have different appearances under a microscope.1 Another difference is that nonseminomas typically grow and spread more quickly than seminomas.

27

Formation of a large Vasa-positive germ granule and its inheritance by germ cells in the enigmatic Chaetognaths  

Microsoft Academic Search

Chaetognaths (arrow worms) are abundant hermaphrodite marine organisms whose phylogenetic position amongst protostomes and deuterostomes is still debated. Ancient histological observations dating from a century ago described the presence in eggs of a large granule, presumed to be a germ plasm, and its probable inheritance in four primary germ cells (PGCs). Using videomicroscopy, electron microscopy and immunocytochemistry (labelling with anti-Vasa

Danièle Carré; Chakib Djediat; Christian Sardet

2002-01-01

28

Genomic Landscape of Developing Male Germ Cells  

PubMed Central

Spermatogenesis is a highly orchestrated developmental process by which spermatogonia develop into mature spermatozoa. This process involves many testis- or male germ cell-specific gene products whose expressions are strictly regulated. In the past decade the advent of high-throughput gene expression analytical techniques has made functional genomic studies of this process, particularly in model animals such as mice and rats, feasible and practical. These studies have just begun to reveal the complexity of the genomic landscape of the developing male germ cells. Over 50% of the mouse and rat genome are expressed during testicular development. Among transcripts present in germ cells, 40% – 60% are uncharacterized. A number of genes, and consequently their associated biological pathways, are differentially expressed at different stages of spermatogenesis. Developing male germ cells present a rich repertoire of genetic processes. Tissue-specific as well as spermatogenesis stage-specific alternative splicing of genes exemplifies the complexity of genome expression. In addition to this layer of control, discoveries of abundant presence of antisense transcripts, expressed psuedogenes, non-coding RNAs (ncRNA) including long ncRNAs, microRNAs (miRNAs) and Piwi-interacting RNAs (piRNAs), and retrogenes all point to the presence of multiple layers of expression and functional regulation in male germ cells. It is anticipated that application of systems biology approaches will further our understanding of the regulatory mechanism of spermatogenesis.† PMID:19306351

Lee, Tin-Lap; Pang, Alan Lap-Yin; Rennert, Owen M.; Chan, Wai-Yee

2010-01-01

29

Dppa3 / Pgc7 / stellais a maternal factor and is not required for germ cell specification in mice  

E-print Network

Background: In mice, germ cells are specified through signalling between layers of cells comprising the primitive embryo. The function of Dppa3 (also known as Pgc7 or stella), a gene expressed in primordial germ cells at ...

Bortvin, Alex

30

Embryonic germ cell lines and their derivation from mouse primordial germ cells.  

PubMed

When primordial germ cells of the mouse are cultured on feeder layers with the addition of the polypeptide signalling molecules leukaemia inhibitory factor, Steel factor and basic fibroblast growth factor they give rise to cells that resemble undifferentiated blastocyst-derived embryonic stem cells. These primordial germ cell-derived embryonic germ cells (EG cells) can be induced to differentiate extensively in culture and also form teratocarcinomas when injected into nude mice. Additionally, they contribute to chimeras when injected into host blastocysts. We have derived multiple EG cell lines from 8.5 days post coitum (dpc) embryos of C57BL/6 inbred mice. Four independent EG cell lines with normal male karyotypes have formed chimeras (up to 70% coat colour chimerism) when injected into BALB/c host blastocysts. Chimeric mice from all four cell lines are fertile, but only those from one line have transmitted coat colour markers through the germline. Studies have also been carried out to determine whether gonadal primordial germ cells can give rise to pluripotent EG cells. Germ cells from gonads of 15.5 dpc C57BL/6 embryos and newborn mice failed to produce EG cell lines. EG cell lines capable of forming teratocarcinomas and coat colour chimeras have been established from primordial germ cells of 12.5 dpc genital ridges. We are currently testing the genomic imprinting status of the insulin-like growth factor type 2 receptor gene (Igf2r) in our different EG cell lines. PMID:7835148

Labosky, P A; Barlow, D P; Hogan, B L

1994-01-01

31

Germ-line variants in methyl-group metabolism genes and susceptibility to DNA methylation in normal tissues and human primary tumors.  

PubMed

Aberrant DNA methylation is recognized as being a common feature of human neoplasia.CpG island hypermethylation and global genomic hypomethylation occur simultaneously in the cancer cell. However, very little is known about the interindividual inherited susceptibility to these epigenetic processes. To address this matter, we have genotyped in 233 cancer patients (with colorectal, breast, or lung tumors), four germ-line variants in three key genes involved in the metabolism of the methyl group, methylene-tetrahydrofolate reductase, methionine synthase, and cystathionine beta-synthase, and analyzed their association with DNA methylation parameters. The epigenetic features analyzed were the 5-methylcytosine content in the genome of the tumors and their normal counterparts, and the presence of CpG island hypermethylation of tumor suppressor genes (p16(INK4a), p14(ARF), hMLH1, MGMT, APC, LKB1, DAPK, GSTP1, BRCA1, RAR beta 2, CDH1, and RASSF1). Two positive associations were found. First, carriers of genotypes containing the methylene-tetrahydrofolate reductase 677T allele show constitutive low levels of 5-methylcytosine in their genomes (P = 0.002), and tumors in these patients do not achieve severe degrees of global hypomethylation (P = 0.047). Second, tumors occurring in homozygous carriers of the methionine synthase 2756G allele show a lower number of hypermethylated CpG islands of tumor suppressor genes (P = 0.029). The existence of these associations may provide another example of the interplay between genetic and epigenetic factors in the cancer cell. PMID:12154064

Paz, Maria F; Avila, Sonia; Fraga, Mario F; Pollan, Marina; Capella, Gabriel; Peinado, Miquel Angel; Sanchez-Cespedes, Montserrat; Herman, James G; Esteller, Manel

2002-08-01

32

Environmentally Induced Transgenerational Epigenetic Reprogramming of Primordial Germ Cells and the Subsequent Germ Line  

PubMed Central

A number of environmental factors (e.g. toxicants) have been shown to promote the epigenetic transgenerational inheritance of disease and phenotypic variation. Transgenerational inheritance requires the germline transmission of altered epigenetic information between generations in the absence of direct environmental exposures. The primary periods for epigenetic programming of the germ line are those associated with primordial germ cell development and subsequent fetal germline development. The current study examined the actions of an agricultural fungicide vinclozolin on gestating female (F0 generation) progeny in regards to the primordial germ cell (PGC) epigenetic reprogramming of the F3 generation (i.e. great-grandchildren). The F3 generation germline transcriptome and epigenome (DNA methylation) were altered transgenerationally. Interestingly, disruptions in DNA methylation patterns and altered transcriptomes were distinct between germ cells at the onset of gonadal sex determination at embryonic day 13 (E13) and after cord formation in the testis at embryonic day 16 (E16). A larger number of DNA methylation abnormalities (epimutations) and transcriptional alterations were observed in the E13 germ cells than in the E16 germ cells. These observations indicate that altered transgenerational epigenetic reprogramming and function of the male germline is a component of vinclozolin induced epigenetic transgenerational inheritance of disease. Insights into the molecular control of germline transmitted epigenetic inheritance are provided. PMID:23869203

Skinner, Michael K.; Haque, Carlos Guerrero-Bosagna M.; Nilsson, Eric; Bhandari, Ramji; McCarrey, John R.

2013-01-01

33

The boundary layers as the primary transport regions of the earth's magnetotail  

NASA Technical Reports Server (NTRS)

A comprehensive survey of ISEE and IMP LEPEDEA plasma measurements in the earth's magnetotail reveals that the magnetospheric boundary layer and the plasma sheet boundary layer are the primary transport regions there. These plasma measurements also reveal various components of the plasma sheet, including the central plasma sheet and plasma sheet boundary layer. A significant new result reported here is that of cold- and hot-plasma components that are spatially co-present within the central plasma sheet. Such plasma components cannot be explained merely by temporal variations in spectra involving the entire plasma sheet. Contributions to a low temperature component of the plasma sheet enter directly from the boundary layer located along the magnetotail flanks. Field-aligned flows predominate within the plasma sheet boundary layer which is almost always present and is located near the high- and low-latitude border of the plasma sheet. The plasma sheet boundary layer comprises highly anisotropic ion distributions, including counter-streaming ion beams, that evolve into the hot, isotropic component of the plasma sheet. Tailward acceleration regions generate these ion beams with plasma input from the magnetospheric boundary layer. Antisunward-flowing ion beams, at E/q less than 1 kV and of ionospheric composition, are frequently observed in the plasma sheet boundary layer and in tail lobes. These ion beams are likely accelerated at low altitude over the polar cap and especially along auroral field lines.

Eastman, T. E.; Frank, L. A.; Huang, C. Y.

1985-01-01

34

RNA Granules in Germ Cells  

PubMed Central

Germ granules” are cytoplasmic, nonmembrane-bound organelles unique to germline. Germ granules share components with the P bodies and stress granules of somatic cells, but also contain proteins and RNAs uniquely required for germ cell development. In this review, we focus on recent advances in our understanding of germ granule assembly, dynamics, and function. One hypothesis is that germ granules operate as hubs for the posttranscriptional control of gene expression, a function at the core of the germ cell differentiation program. PMID:21768607

Voronina, Ekaterina; Seydoux, Geraldine; Sassone-Corsi, Paolo; Nagamori, Ippei

2011-01-01

35

Fish germ cells.  

PubMed

Fish, like many other animals, have two major cell lineages, namely the germline and soma. The germ-soma separation is one of the earliest events of embryonic development. Germ cells can be specifically labeled and isolated for culture and transplantation, providing tools for reproduction of endangered species in close relatives, such as surrogate production of trout in salmon. Haploid cell cultures, such as medaka haploid embryonic stem cells have recently been obtained, which are capable of mimicking sperm to produce fertile offspring, upon nuclear being directly transferred into normal eggs. Such fish originated from a mosaic oocyte that had a haploid meiotic nucleus and a transplanted haploid mitotic cell culture nucleus. The first semi-cloned fish is Holly. Here we review the current status and future directions of understanding and manipulating fish germ cells in basic research and reproductive technology. PMID:20596909

Xu, HongYan; Li, MingYou; Gui, JianFang; Hong, YunHan

2010-04-01

36

Genetics of germ cell development  

E-print Network

The germ line represents a continuous cellular link between generations and between species, but the germ cells themselves develop in a specialized, organism-specific context. The model organisms Caenorhabditis elegans, ...

Lesch, Bluma J.

37

Intracranial germ cell tumor.  

PubMed

Germ cell tumours represent about 3 to 8% of pediatric brain tumours. Occurrence of diabetes insipidus is common in the case of suprasellar germ cell tumors. The diagnosis may be advanced by MRI owing to the location and relatively univocal characteristics of the lesion signal. The existence of a bifocal mass developed in both suprasellar region and pineal zone is highly suggestive of a germinoma. The most important notion is to recognize that at the time of diabetes insipidus diagnosis in a child, the cerebral mass might be too small to be identified by MRI. In such patients, repeating imaging study should be obtained. PMID:20957891

Kreutz, J; Rausin, L; Weerts, E; Tebache, M; Born, J; Hoyoux, C

2010-01-01

38

AiGERM: A logic programming front end for GERM  

NASA Technical Reports Server (NTRS)

AiGerm (Artificially Intelligent Graphical Entity Relation Modeler) is a relational data base query and programming language front end for MCC (Mission Control Center)/STP's (Space Test Program) Germ (Graphical Entity Relational Modeling) system. It is intended as an add-on component of the Germ system to be used for navigating very large networks of information. It can also function as an expert system shell for prototyping knowledge-based systems. AiGerm provides an interface between the programming language and Germ.

Hashim, Safaa H.

1990-01-01

39

Germs and the Body  

NSDL National Science Digital Library

This Science NetLinks lesson explores germs, where they exist, and how they can affect the body. It also addresses a common misconception that students of all ages may have - that factors important to health are beyond their personal control. In studying bacteria, students will also learn preventative measures they can take to stay healthy.

Science Netlinks

2002-08-01

40

Wheat Germ DNA Extraction  

NSDL National Science Digital Library

This laboratory exercise is designed to show learners how DNA can easily be extracted from wheat germ using simple materials. Use this experiment to supplement any unit on genetics and to demonstrate how scientists study DNA. Adult supervision is recommended. This resource guide includes tips and suggestions for instructors as well as other DNA extraction experiments and a chart for learners to answer questions.

Lana Hays

2009-01-01

41

PGL-1, a Predicted RNA-Binding Component of Germ Granules, Is Essential for Fertility in C. elegans  

Microsoft Academic Search

Germ cells are distinct from somatic cells in their immortality, totipotency, and ability to undergo meiosis. Candidates for components that guide the unique germline program are the distinctive granules observed in germ cells of many species. We show that a component of germ granules is essential for fertility in C. elegans and that its primary function is in germline proliferation.

Ichiro Kawasaki; Yhong-Hee Shim; Jay Kirchner; Joshua Kaminker; William B. Wood; Susan Strome

1998-01-01

42

Callosal connections of the ferret primary auditory cortex  

Microsoft Academic Search

The callosal connections of ferret auditory cortex were studied by making multiple injections of wheat germ agglutinin-horseradish\\u000a peroxidase into the middle ectosylvian gyrus or by packing crystals of horseradish peroxidase into the transected corpus callosum.\\u000a The primary area (AI) had strong callosal connections that arose from somata mainly located in layer III. Other layers contained\\u000a sparsely distributed cells that projected

M. N. Wallace; Morag S. Harper

1997-01-01

43

High-dose chemotherapy followed by autologous peripheral blood stem cell transplantation for recurrent primary mediastinal malignant germ cell tumor: a case report.  

PubMed

A 15-yr-old boy presented with an anterior mediastinal mass, multiple lung metastases and obstruction of the left brachiocephalic vein, the superior vena cava and the subclavian vein. Tumor biopsy by CT guidance confirmed a diagnosis of GCT. Five courses of BEP therapy were performed, and CT of the chest revealed reduction in the anterior mediastinal mass and disappearance of the multiple lung metastases. We performed the anterior mediastinal mass extraction followed by adjuvant chemotherapy consisting of ICE and TIP. However, the AFP levels became elevated soon after. Abnormal accumulation was observed in the right upper lung by DW-MRI. After the operation, two courses of TI chemotherapy and two courses of HDCT followed by auto-PBSCT were performed. He was complicated with auditory disorder and renal dysfunction. Although HDCT followed by auto-PBSCT was effective for the relapsed primary mediastinal GCT, a treatment strategy avoiding late complications is warranted. PMID:24373121

Keino, Dai; Kondoh, Kensuke; Murata, Shunsuke; Ohyama, Ryo; Morimoto, Mizuho; Muto, Shinji; Fukuda, Miho; Wakisaka, Munechika; Kitagawa, Hiroaki; Kinoshita, Akitoshi

2014-03-01

44

Primary structure and glycosylation of the S-layer protein of Haloferax volcanii.  

PubMed

The outer surface of the archaebacterium Haloferax volcanii (formerly named Halobacterium volcanii) is covered with a hexagonally packed surface (S) layer. The gene coding for the S-layer protein was cloned and sequenced. The mature polypeptide is composed of 794 amino acids and is preceded by a typical signal sequence of 34 amino acid residues. A highly hydrophobic stretch of 20 amino acids at the C-terminal end probably serves as a transmembrane domain. Clusters of threonine residues are located adjacent to this membrane anchor. The S-layer protein is a glycoprotein containing both N- and O-glycosidic bonds. Glucosyl-(1----2)-galactose disaccharides are linked to threonine residues. The primary structure and the glycosylation pattern of the S-layer glycoproteins from Haloferax volcanii and from Halobacterium halobium were compared and found to exhibit distinct differences, despite the fact that three-dimensional reconstructions from electron micrographs revealed no structural differences at least to the 2.5-nm level attained so far (M. Kessel, I. Wildhaber, S. Cohe, and W. Baumeister, EMBO J. 7:1549-1554, 1988). PMID:2123862

Sumper, M; Berg, E; Mengele, R; Strobel, I

1990-12-01

45

Target-specific properties of thalamocortical synapses onto layer 4 of mouse primary visual cortex.  

PubMed

In primary sensory cortices, thalamocortical (TC) inputs can directly activate excitatory and inhibitory neurons. In vivo experiments in the main input layer (L4) of primary visual cortex (V1) have shown that excitatory and inhibitory neurons have different tuning properties. The different functional properties may arise from distinct intrinsic properties of L4 neurons, but could also depend on cell type-specific properties of the synaptic inputs from the lateral geniculate nucleus of the thalamus (LGN) onto L4 neurons. While anatomical studies identified LGN inputs onto both excitatory and inhibitory neurons in V1, their synaptic properties have not been investigated. Here we used an optogenetic approach to selectively activate LGN terminal fields in acute coronal slices containing V1, and recorded monosynaptic currents from excitatory and inhibitory neurons in L4. LGN afferents made monosynaptic connections with pyramidal (Pyr) and fast-spiking (FS) neurons. TC EPSCs on FS neurons were larger and showed steeper short-term depression in response to repetitive stimulation than those on Pyr neurons. LGN inputs onto Pyr and FS neurons also differed in postsynaptic receptor composition and organization of presynaptic release sites. Together, our results demonstrate that LGN input onto L4 neurons in mouse V1 have target-specific presynaptic and postsynaptic properties. Distinct mechanisms of activation of feedforward excitatory and inhibitory neurons in the main input layer of V1 are likely to endow neurons with different response properties to incoming visual stimuli. PMID:25392512

Kloc, Michelle; Maffei, Arianna

2014-11-12

46

Superficial layer pyramidal cells communicate heterogeneously between multiple functional domains of cat primary visual cortex  

PubMed Central

The axons of pyramidal neurons in the superficial layers of the neocortex of higher mammals form lateral networks of discrete clusters of synaptic boutons. In primary visual cortex the clusters are reported to link domains that share the same orientation preferences, but how individual neurons contribute to this network is unknown. Here we performed optical imaging to record the intrinsic signal, which is an indirect measure of neuronal firing, and determined the global map of orientation preferences in the cat primary visual system. In the same experiment, single cells were recorded and labelled intracellularly. We found that individual axons arborise within the retinotopic representation of the classical receptive field, but their bouton clusters were not aligned along their preferred axis of orientation along the retinotopic map. Axon clusters formed in a variety of different orientation domains, not just the like-orientation domains. This topography and heterogeneity of single-cell connectivity provides circuits for normalization and context-dependent feature processing of visual scenes. PMID:25341917

Martin, Kevan A. C.; Roth, Stephan; Rusch, Elisha S.

2014-01-01

47

Analytic surface germs with minimal Pythagoras number  

Microsoft Academic Search

We determine all complete intersection surface germs whose Pythagoras number is 2, and find that they are all embedded in R3 and have the property that every positive semidefinite analytic function germ is a sum of squares of analytic function germs. In addition, we discuss completely these properties for mixed surface germs in R3. Finally, we find in higher embedding

José F. Fernando; F. Ciencias Matematicas

2003-01-01

48

Extragonadal Germ Cell Cancer (EGC)  

MedlinePLUS

... germ cells are first seen outside of the embryo in the yolk sac. At about 4 to ... weeks of development, these cells migrate into the embryo where they populate the developing testes or ovaries. ...

49

Palifosfamide in Treating Patients With Recurrent Germ Cell Tumors  

ClinicalTrials.gov

Adult Central Nervous System Germ Cell Tumor; Adult Teratoma; Malignant Extragonadal Germ Cell Tumor; Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Extragonadal Seminoma; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2015-01-30

50

Security risk assessment of the primary layer of wavelength division multiplexing passive optical network  

NASA Astrophysics Data System (ADS)

Next-generation passive optical access networks come to the fore nowadays. These optical next-generation networks are the response to the increasing qualitative requirements from end users. Technologies using Time Division Multiplexing include NG-PON (XG-PON 1 and XG-PON 2) and 10GEPON. Their advantage is the applicability to older topologies, which are operated by the original technology of passive optical access networks. Wavelength Division Multiplexing Passive Optical Network (WDM-PON) is an alternative also belonging to next-generation networks. Time Division Multiplexing is in this case replaced by Wavelength Division Multiplexing. Certain variants of WDM-PON use a combination of broadband light source, optical circulator, optical phased array and tunable FP laser. Construction of the terminal units (ONU) is advantageous because it can always tune in to the appropriate wavelength in the given optical DWDM channel (100 GHz). The disadvantage is the increased security risk on the primary layer due to channel crosstalk in an optical phased array (AWG). The aim of this paper is to assess the degree of security risk in real conditions. The article includes both simulation and real measurements in C + L bands with 100 GHz DWDM spacing.

Koudelka, Petr; Siska, Petr; Latal, Jan; Poboril, Radek; Hajek, Lukas; Kepak, Stanislav; Vasinek, Vladimir

2015-01-01

51

Physiology of layer 5 pyramidal neurons in mouse primary visual cortex: coincidence detection through bursting.  

PubMed

L5 pyramidal neurons are the only neocortical cell type with dendrites reaching all six layers of cortex, casting them as one of the main integrators in the cortical column. What is the nature and mode of computation performed in mouse primary visual cortex (V1) given the physiology of L5 pyramidal neurons? First, we experimentally establish active properties of the dendrites of L5 pyramidal neurons of mouse V1 using patch-clamp recordings. Using a detailed multi-compartmental model, we show this physiological setup to be well suited for coincidence detection between basal and apical tuft inputs by controlling the frequency of spike output. We further show how direct inhibition of calcium channels in the dendrites modulates such coincidence detection. To establish the singe-cell computation that this biophysics supports, we show that the combination of frequency-modulation of somatic output by tuft input and (simulated) calcium-channel blockage functionally acts as a composite sigmoidal function. Finally, we explore how this computation provides a mechanism whereby dendritic spiking contributes to orientation tuning in pyramidal neurons. PMID:25768881

Shai, Adam S; Anastassiou, Costas A; Larkum, Matthew E; Koch, Christof

2015-03-01

52

Physiology of Layer 5 Pyramidal Neurons in Mouse Primary Visual Cortex: Coincidence Detection through Bursting  

PubMed Central

L5 pyramidal neurons are the only neocortical cell type with dendrites reaching all six layers of cortex, casting them as one of the main integrators in the cortical column. What is the nature and mode of computation performed in mouse primary visual cortex (V1) given the physiology of L5 pyramidal neurons? First, we experimentally establish active properties of the dendrites of L5 pyramidal neurons of mouse V1 using patch-clamp recordings. Using a detailed multi-compartmental model, we show this physiological setup to be well suited for coincidence detection between basal and apical tuft inputs by controlling the frequency of spike output. We further show how direct inhibition of calcium channels in the dendrites modulates such coincidence detection. To establish the singe-cell computation that this biophysics supports, we show that the combination of frequency-modulation of somatic output by tuft input and (simulated) calcium-channel blockage functionally acts as a composite sigmoidal function. Finally, we explore how this computation provides a mechanism whereby dendritic spiking contributes to orientation tuning in pyramidal neurons. PMID:25768881

Shai, Adam S.; Anastassiou, Costas A.; Larkum, Matthew E.; Koch, Christof

2015-01-01

53

Nuclear Reprogramming in Mouse Primordial Germ Cells: Epigenetic Contribution  

PubMed Central

The unique capability of germ cells to give rise to a new organism, allowing the transmission of primary genetic information from generation to generation, depends on their epigenetic reprogramming ability and underlying genomic totipotency. Recent studies have shown that genome-wide epigenetic modifications, referred to as “epigenetic reprogramming”, occur during the development of the gamete precursors termed primordial germ cells (PGCs) in the embryo. This reprogramming is likely to be critical for the germ line development itself and necessary to erase the parental imprinting and setting the base for totipotency intrinsic to this cell lineage. The status of genome acquired during reprogramming and the associated expression of key pluripotency genes render PGCs susceptible to transform into pluripotent stem cells. This may occur in vivo under still undefined condition, and it is likely at the origin of the formation of germ cell tumors. The phenomenon appears to be reproduced under partly defined in vitro culture conditions, when PGCs are transformed into embryonic germ (EG) cells. In the present paper, I will try to summarize the contribution that epigenetic modifications give to nuclear reprogramming in mouse PGCs. PMID:21969835

De Felici, Massimo

2011-01-01

54

Aerosol Measurements in the Atmospheric Surface Layer at L'Aquila, Italy: Focus on Biogenic Primary Particles  

NASA Astrophysics Data System (ADS)

Two year measurements of aerosol concentration and size distribution (0.25 ?m < d < 30 ?m) in the atmospheric surface layer, collected in L'Aquila (Italy) with an optical particle counter, are reported and analysed for the different modes of the particle size distribution. A different seasonal behaviour is shown for fine mode aerosols (largely produced by anthropogenic combustion), coarse mode and large-sized aerosols, whose abundance is regulated not only by anthropogenic local production, but also by remote natural sources (via large scale atmospheric transport) and by local sources of primary biogenic aerosols. The observed total abundance of large particles with diameter larger than 10 ?m is compared with a statistical counting of primary biogenic particles, made with an independent technique. Results of these two observational approaches are analysed and compared to each other, with the help of a box model driven by observed meteorological parameters and validated with measurements of fine and coarse mode aerosols and of an atmospheric primary pollutant of anthropogenic origin (NOx). Except in winter months, primary biogenic particles in the L'Aquila measurement site are shown to dominate the atmospheric boundary layer population of large aerosol particles with diameter larger than 10 ?m (about 80 % of the total during summer months), with a pronounced seasonal cycle, contrary to fine mode aerosols of anthropogenic origin. In order to explain these findings, the main mechanisms controlling the abundance and variability of particulate matter tracers in the atmospheric surface layer are analysed with the numerical box-model.

Pitari, Giovanni; Coppari, Eleonora; De Luca, Natalia; Di Carlo, Piero; Pace, Loretta

2014-09-01

55

General Information About Childhood Central Nervous System Germ Cell Tumors  

MedlinePLUS

General Information About Childhood Central Nervous System Germ Cell Tumors Key Points for This Section Childhood central ... of recovery). Childhood central nervous system (CNS) germ cell tumors form from germ cells. Germ cells are ...

56

General Information about Extragonadal Germ Cell Tumors  

MedlinePLUS

... eyes. Imaging and blood tests are used to detect (find) and diagnose extragonadal germ cell tumors. The ... The following three tumor markers are used to detect extragonadal germ cell tumor: Alpha-fetoprotein (AFP). Beta- ...

57

Dazl regulates mouse embryonic germ cell development  

E-print Network

In the mouse, germ cells can undergo differentiation to become either oocytes or spermatozoa in response to sex of their gonadal environment. The nature of the germ cell-intrinsic aspects of this signaling have not been ...

Gill, Mark E

2010-01-01

58

Testicular germ cell tumours: predisposition genes and the male germ cell niche  

Microsoft Academic Search

Testicular germ cell tumours (TGCTs) of adults and adolescents are putatively derived from primordial germ cells or gonocytes. Recently reported genome-wide association studies implicate six gene loci that predispose to TGCT development. Remarkably, the functions of proteins encoded by genes within these regions bridge our understanding between the pathways involved in primordial germ cell physiology, male germ cell development and

Duncan Gilbert; Elizabeth Rapley; Janet Shipley

2011-01-01

59

The primary walls of cotton fibers contain an ensheathing pectin layer  

Microsoft Academic Search

Summary Cotton fiber walls (1–2 days post anthesis) are distinctly bilayered compared to those of nonfiber epidermal cells, with a more electron-opaque outer layer and a less electron-opaque, more finely fibrillar inner layer. When probed with antibodies and affinity probes to various saccharides, xyloglucans and cellulose are found exclusively in the inner layer and de-esterified pectins and extensin exclusively in

K. C. Vaughn; R. B. Turley

1999-01-01

60

Survival of patients with nonseminomatous germ cell cancer: a review of the IGCC classification by Cox regression and recursive partitioning  

Microsoft Academic Search

The International Germ Cell Consensus (IGCC) classification identifies good, intermediate and poor prognosis groups among patients with metastatic nonseminomatous germ cell tumours (NSGCT). It uses the risk factors primary site, presence of nonpulmonary visceral metastases and tumour markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and lactic dehydrogenase (LDH). The IGCC classification is easy to use and remember, but lacks flexibility.

M R van Dijk; E W Steyerberg; S P Stenning; E Dusseldorp; J D F Habbema; van Dijk

2004-01-01

61

iBioSeminar: Germ Cell Development  

NSDL National Science Digital Library

When an egg is fertilized, two distinct groups of cells are formed; the somatic cells which give rise to all the structures in body and will ultimately die, and the primordial germ cells which become germ line stem cells that produce sperm and egg and thus, can give rise to another generation. Hence, germ cells are responsible for the maintenance of a species.

Ruth Lehmann (New York University School of Medicine; )

2009-07-01

62

HISTORY OF GERM CELL MUTAGENESIS  

EPA Science Inventory

Much of the early work on germ cell mutation analysis was conducted with nonmammalian species, but this historical overview will begin with the rodent studies that provided quantitative data on induced mutations. The initial studies of mutation induction utilized the newly develo...

63

PKA, Germ Cells, and Fertility  

NSDL National Science Digital Library

Temporal and spatial regulation of PKA activity are essential for vigorous sperm motility and for the resumption of meiosis in oocytes, two events required for successful fertilization. Genetic mutations in mice that affect PKA signaling in germ cells lead to infertility and illustrate the importance of this pathway in mammalian reproduction.

2007-02-01

64

Late toxicity after treatment for testicular germ cell cancer  

Microsoft Academic Search

Summary  \\u000a Improved survival in testicular cancer has been accompanied by concern about long-term side effects of chemotherapy or radiotherapy.\\u000a Secondary malignant neoplasia represents one of the worst possible long-term complications, leading to death in patients cured\\u000a of their primary malignancy. Patients with testicular germ cell tumors appear to have a 2-fold increased risk of developing\\u000a any second cancer 25–30 years

A. Jakob; C. Kollmannsberger; L. Kanz; C. Bokemeyer

1998-01-01

65

Diversity and cell type specificity of local excitatory connections to neurons in layer 3B of monkey primary visual cortex.  

PubMed

In the primary visual cortex of macaque monkeys, laminar and columnar axonal specificity are correlated with functional differences between locations. We describe evidence that embedded within this anatomical framework is finer specificity of functional connections. Photostimulation-based mapping of functional input to 31 layer 3B neurons revealed that input sources to individual cells were highly diverse. Although some input differences were correlated with neuronal anatomy, no 2 neurons received excitatory input from the same cortical layers. Thus, input diversity reveals far more cell types than does anatomical diversity. This implies relatively little functional redundancy; despite trends related to laminar or columnar position, pools of neurons contributing uniquely to visual processing are likely relatively small. These results also imply that similarities in the anatomy of circuits in different cortical areas or species may not indicate similar functional connectivity. PMID:10719899

Sawatari, A; Callaway, E M

2000-02-01

66

Comparison of relation between visual function index and retinal nerve fiber layer structure by optical coherence tomography among primary open angle glaucoma and primary angle closure glaucoma eyes  

PubMed Central

Purpose: To compare the visual field index (VFI) in primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) eyes, and to study the correlation with disc variables on optical coherence tomography (OCT) in all stages of severity. Materials and Methods: Thirty POAG and PACG underwent Humphrey visual field 24-2 along with detailed examination. They also underwent stratus OCT imaging of the optic nerve and retinal nerve fiber layer (RNFL). The correlation of VFI with RNFL thickness was compared in POAG and PACG. Results: The VFI significantly differed between POAG and PACG, with POAG eyes apparently having a better VFI at all severities of glaucoma. There were statistically significant differences in the superior max (Smax) and inferior max (Imax) in early and moderate POAG and PACG eyes. In early and moderate glaucoma, multivariate regression showed that maximum correlation of the VFI was seen with the mean deviation (b = 1.7, P < 0.001), average and superior RNFL thickness (b = 2.1, P < 0.001 and b = 1.8, P = 0.03, respectively), and age (b = 0.7, P = 0.04); while no correlation was seen with intraocular pressure (IOP), axial length, sex, or other clinical variables. VFI did not correlate well with RNFL thickness or other disc variables on OCT in severe glaucoma. Conclusion: VFI may not serve as a useful indicator of visual function in severe glaucoma. More useful indicators are required to monitor glaucoma patients with severe damage. PMID:24799794

Rao, Aparna

2014-01-01

67

Transport of germ plasm on astral microtubules directs germ cell development in Drosophila  

PubMed Central

Summary Background In many organisms, germ cells are segregated from the soma through the inheritance of the specialized germ plasm, which contains mRNAs and proteins that specify germ cell fate and promote germline development. Whereas germ plasm assembly has been well characterized, mechanisms mediating germ plasm inheritance are poorly understood. In the Drosophila embryo, germ plasm is anchored to the posterior cortex and nuclei that migrate into this region give rise to the germ cell progenitors, or pole cells. How the germ plasm interacts with these nuclei for pole cell induction and is selectively incorporated into the forming pole cells is not known. Results Live imaging of two conserved germ plasm components, nanos mRNA and Vasa protein, revealed that germ plasm segregation is a dynamic process involving active transport of germ plasm RNA-protein complexes coordinated with nuclear migration. We show that centrosomes accompanying posterior nuclei induce release of germ plasm from the cortex and recruit these components by dynein-dependent transport on centrosome-nucleated microtubules. As nuclei divide, continued transport on astral microtubules partitions germ plasm to daughter nuclei, leading to its segregation into pole cells. Disruption of these transport events prevents incorporation of germ plasm into pole cells and impairs germ cell development. Conclusions Our results indicate that active transport of germ plasm is essential for its inheritance and ensures the production of a discrete population of germ cell progenitors endowed with requisite factors for germline development. Transport on astral microtubules may provide a general mechanism for the effective segregation of cell fate determinants. PMID:21376599

Lerit, Dorothy A.; Gavis, Elizabeth R.

2011-01-01

68

Bile salts of germ-free domestic fowl and pigs  

PubMed Central

1. The bile of germ-free domestic fowl contains taurine conjugates of 3?,7?-dihydroxy-5?-cholan-24-oic acid (chenodeoxycholic acid), 3?,7?,12?-trihydroxy-5?-cholan-24-oic acid (cholic acid) and its 5?-epimer (allocholic acid): that of germ-free pigs contains glycine and taurine conjugates of chenodeoxycholic acid, 3?,6?-dihydroxy-5?-cholan-24-oic acid (hyodeoxycholic acid), 3?,6?,7?-trihydroxy-5?-cholan-24-oic acid (hyocholic acid) and (probably) cholic acid. Keto acids were not found. 2. Allocholic acid and hyodeoxycholic acid are thus proved to be primary bile acids in intact animals. 3. The evolutionary and biochemical implications of these findings are briefly considered. PMID:5128663

Haslewood, G. A. D.

1971-01-01

69

Multiple layer 5 pyramidal cell subtypes relay cortical feedback from secondary to primary motor areas in rats.  

PubMed

Higher-order motor cortices, such as the secondary motor area (M2) in rodents, select future action patterns and transmit them to the primary motor cortex (M1). To better understand motor processing, we characterized "top-down" and "bottom-up" connectivities between M1 and M2 in the rat cortex. Somata of pyramidal cells (PCs) in M2 projecting to M1 were distributed in lower layer 2/3 (L2/3) and upper layer 5 (L5), whereas PCs projecting from M1 to M2 had somata distributed throughout L2/3 and L5. M2 afferents terminated preferentially in upper layer 1 of M1, which also receives indirect basal ganglia output through afferents from the ventral anterior and ventromedial thalamic nuclei. On the other hand, M1 afferents terminated preferentially in L2/3 of M2, a zone receiving indirect cerebellar output through thalamic afferents from the ventrolateral nucleus. While L5 corticopontine (CPn) cells with collaterals to the spinal cord did not participate in corticocortical projections, CPn cells with collaterals to the thalamus contributed preferentially to connections from M2 to M1. L5 callosal projection (commissural) cells participated in connectivity between M1 and M2 bidirectionally. We conclude that the connectivity between M1 and M2 is directionally specialized, involving specific PC subtypes that selectively target lamina receiving distinct thalamocortical inputs. PMID:23551921

Ueta, Yoshifumi; Otsuka, Takeshi; Morishima, Mieko; Ushimaru, Mika; Kawaguchi, Yasuo

2014-09-01

70

Treatment Options for Childhood Extracranial Germ Cell Tumors  

MedlinePLUS

... trials is available from the NCI Web site . Malignant Gonadal Germ Cell Tumors Malignant Testicular Germ Cell Tumors Treatment of malignant testicular ... trials is available from the NCI Web site . Malignant Ovarian Germ Cell Tumors Dysgerminomas Treatment of stage ...

71

Cell-type-specific sub- and suprathreshold receptive fields of layer 4 and layer 2/3 pyramids in rat primary visual cortex.  

PubMed

Connectivity of cortical pyramidal neurons is layer-specific in the primary visual cortex (V1) and this is thought to be reflected in different receptive field (RF) properties of layer 4 and layer 2/3 pyramidal neurons (L4Ps and L2/3Ps, respectively). However, it remains unclear how the two cell populations convert incoming visually driven synaptic inputs into action potential (AP) outputs. Here I compared postsynaptic potentials (PSPs) and AP responses of L4Ps and L2/3Ps in the binocular portion of rat V1 by intrinsic optical imaging (IOI)-targeted whole-cell recordings followed by anatomical identification and dendritic reconstructions. L2/3Ps had about 2-fold longer dendritic branches and a higher number of branch points and endings in their apical portions. Functionally, L2/3Ps had more hyperpolarized resting potentials and lower rates of spontaneous APs (medians: 0.07 vs. 0.60 AP/s). PSP responses to optimally oriented moving bars were comparable in terms of amplitude (16.0±0.9 vs. 17.3±1.1 mV for L2/3Ps and L4Ps, respectively), reliability and size of the RF. The modulated component of subthreshold responses of L4Ps to optimal sinusoidal drifting gratings was larger and their PSP onset latency in response to bars flashed in the cell's RF center were shorter (60 vs. 86 ms). In contrast to the similarities of PSP responses to moving bars, AP responses of L2/3Ps were more sparse (medians: 0.7 vs. 2.9 APs/stimulus passage), less reliable, but sharper in terms of angular size. Based on the differences of subthreshold inputs, I conclude that L4Ps may receive mostly thalamic inputs, whereas L2/3Ps may receive both thalamic and cortical inputs from layer 4. The comparable subthreshold responses to moving bars are converted by L2/3Ps into sparser but sharper AP outputs possibly by cell-type-specific AP-generating mechanisms or differences in visually driven inhibitory inputs. PMID:21704132

Medini, P

2011-09-01

72

[Germ cell and embryonal tumors].  

PubMed

Germ cell tumors, which constitute approximately 3-5% of tumors of the central nervous system (CNS), can be subdivided into germinomas, embryonal carcinomas, yolk sac tumors, choriocarcinomas, teratomas and mixed germ cell tumors. The diagnosis of intracranial germ cell tumor is based on the clinical symptoms, detection of tumor markers, such as alpha fetoprotein (AFP) and the beta subunit of human chorionic gonadotropin (beta-hCG) in blood and cerebrospinal fluid (CSF), magnetic resonance imaging (MRI) of the brain and spinal cord, CSF cytology and histology. The diagnosis of a secreting germ cell tumor, i.e. a non-germinoma, can be made by the determination of AFP and hCG as tumor markers. Germinomas are radiosensitive but are equally as sensitive to chemotherapy. Teratomas of the CNS are mostly diagnosed in newborns and infants. The most decisive role in the treatment of teratomas is played by as complete a resection as possible. Chemotherapy and irradiation play a subordinate role.Embryonal tumors, which constitute approximately 15-20% of CNS tumors, include medulloblastomas, primitive neuroectodermal tumors (PNET) of the CNS and the atypical teratoid rhabdoid tumor of the CNS. Medulloblastoma is the most common malignant brain tumor in childhood and adolescence. The incidence peak is the fifth year of life with a male predisposition in a ratio of 1.5:1. Medulloblastomas constitute 12-25% of all pediatric CNS tumors and 30-40% of pediatric tumors of the posterior cranial fossa. At the time of diagnosis evidence of dissemination in the CSF cavity is found in approximately 40% of patients. The extreme cell density makes medulloblastomas hyperdense in computed tomography (CT) and can therefore be differentiated from hypodense astrocytomas. The PNETs are histologically related to medulloblastomas, pineoblastomas, atypical teratoid rhabdoid tumors and peripheral neuroblastomas. They are relatively rare in children constituting less than 5% of supratentorial neoplasms. Patients are mostly clinically conspicuous due to macrocephalus and signs of brain pressure and/or seizures. In native CT the solid components of PNETs show a hyperdensity compared to the surrounding brain parenchyma probably due to the high cell density. Cysts and calcification are often detectable. The survival rate of children with CNS tumors has continuously increased in recent years. When corresponding clinical symptoms appear, such as headache, nausea or vomiting when fasting, all of which are evidence of increased intracranial pressure, MRI should be carried out as quickly as possible. Children should be treated in centers with departments of pediatric oncology and hematology and within the framework of studies. PMID:25119569

Reith, W; Mühl-Benninghaus, R; Simgen, A; Yilmaz, U

2014-08-01

73

UNSW Embryology: movies of germ cell migration  

NSDL National Science Digital Library

Timelapse movies showing GFP labeled primordial germ cells during migration in the mouse from Mark Hill''s site courtesy of Molyneaux KA (Molyneaux KA, Stallock J, Schaible K, Wylie C. [See Related Articles] Time-lapse analysis of living mouse germ cell migration. Dev Biol. 2001 Dec 15;240(2):488-98).

Dr. Mark Hill (University of New South Wales Anatomy)

2007-12-31

74

Stochastic specification of primordial germ cells from mesoderm precursors in axolotl embryos  

PubMed Central

A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these disparate mechanisms of PGC specification evolved is unknown. Here, in order to identify the ancestral mechanism of PGC specification in vertebrates, we studied PGC specification in embryos from the axolotl (Mexican salamander), a model for the tetrapod ancestor. In the axolotl, PGCs develop within mesoderm, and classic studies have reported their induction from primitive ectoderm (animal cap). We used an axolotl animal cap system to demonstrate that signalling through FGF and BMP4 induces PGCs. The role of FGF was then confirmed in vivo. We also showed PGC induction by Brachyury, in the presence of BMP4. These conditions induced pluripotent mesodermal precursors that give rise to a variety of somatic cell types, in addition to PGCs. Irreversible restriction of the germ line did not occur until the mid-tailbud stage, days after the somatic germ layers are established. Before this, germline potential was maintained by MAP kinase signalling. We propose that this stochastic mechanism of PGC specification, from mesodermal precursors, is conserved in vertebrates. PMID:24917499

Chatfield, Jodie; O'Reilly, Marie-Anne; Bachvarova, Rosemary F.; Ferjentsik, Zoltan; Redwood, Catherine; Walmsley, Maggie; Patient, Roger; Loose, Mathew; Johnson, Andrew D.

2014-01-01

75

Stochastic specification of primordial germ cells from mesoderm precursors in axolotl embryos.  

PubMed

A common feature of development in most vertebrate models is the early segregation of the germ line from the soma. For example, in Xenopus and zebrafish embryos primordial germ cells (PGCs) are specified by germ plasm that is inherited from the egg; in mice, Blimp1 expression in the epiblast mediates the commitment of cells to the germ line. How these disparate mechanisms of PGC specification evolved is unknown. Here, in order to identify the ancestral mechanism of PGC specification in vertebrates, we studied PGC specification in embryos from the axolotl (Mexican salamander), a model for the tetrapod ancestor. In the axolotl, PGCs develop within mesoderm, and classic studies have reported their induction from primitive ectoderm (animal cap). We used an axolotl animal cap system to demonstrate that signalling through FGF and BMP4 induces PGCs. The role of FGF was then confirmed in vivo. We also showed PGC induction by Brachyury, in the presence of BMP4. These conditions induced pluripotent mesodermal precursors that give rise to a variety of somatic cell types, in addition to PGCs. Irreversible restriction of the germ line did not occur until the mid-tailbud stage, days after the somatic germ layers are established. Before this, germline potential was maintained by MAP kinase signalling. We propose that this stochastic mechanism of PGC specification, from mesodermal precursors, is conserved in vertebrates. PMID:24917499

Chatfield, Jodie; O'Reilly, Marie-Anne; Bachvarova, Rosemary F; Ferjentsik, Zoltan; Redwood, Catherine; Walmsley, Maggie; Patient, Roger; Loose, Mathew; Johnson, Andrew D

2014-06-01

76

Germ cell selection in genetic mosaics in Drosophila melanogaster  

E-print Network

a fraction of the progeny of initially established germ-line precursor cells, or primordial germ cells (PGCsGerm cell selection in genetic mosaics in Drosophila melanogaster Cassandra Extavour* and Antonio´a-Bellido, August 3, 2001 Heritable mutations in the germ line lead to genetically heteroge- neous, or mosaic

Extavour, Cassandra

77

Layer 4 in Primary Visual Cortex of the Awake Rabbit: Contrasting Properties of Simple Cells and Putative Feedforward Inhibitory Interneurons  

PubMed Central

Extracellular recordings were obtained from two cell classes in layer 4 of the awake rabbit primary visual cortex (V1): putative inhibitory interneurons [suspected inhibitory interneurons (SINs)] and putative excitatory cells with simple receptive fields. SINs were identified solely by their characteristic response to electrical stimulation of the lateral geniculate nucleus (LGN, 3+ spikes at >600 Hz), and simple cells were identified solely by receptive field structure, requiring spatially separate ON and/or OFF subfields. Notably, no cells met both criteria, and we studied 62 simple cells and 33 SINs. Fourteen cells met neither criterion. These layer 4 populations were markedly distinct. Thus, SINs were far less linear (F1/F0 < 1), more broadly tuned to stimulus orientation, direction, spatial and temporal frequency, more sensitive to contrast, had much higher spontaneous and stimulus-driven activity, and always had spatially overlapping ON/OFF receptive subfields. SINs responded to drifting gratings with increased firing rates (F0) for all orientations and directions. However, some SINs showed a weaker modulated (F1) response sharply tuned to orientation and/or direction. SINs responded at shorter latencies than simple cells to stationary stimuli, and the responses of both populations could be sustained or transient. Transient simple cells were more sensitive to contrast than sustained simple cells and their visual responses were more frequently suppressed by high contrasts. Finally, cross-correlation between LGN and SIN spike trains confirmed a fast and precisely timed monosynaptic connectivity, supporting the notion that SINs are well suited to provide a fast feedforward inhibition onto targeted cortical populations. PMID:23843510

Zhuang, Jun; Stoelzel, Carl R.; Bereshpolova, Yulia; Huff, Joseph M.; Hei, Xiaojuan; Alonso, Jose-Manuel

2013-01-01

78

A specialized outer layer of the primary cell wall joins elongating cotton fibers into tissue-like bundles.  

PubMed

Cotton (Gossypium hirsutum) provides the world's dominant renewable textile fiber, and cotton fiber is valued as a research model because of its extensive elongation and secondary wall thickening. Previously, it was assumed that fibers elongated as individual cells. In contrast, observation by cryo-field emission-scanning electron microscopy of cotton fibers developing in situ within the boll demonstrated that fibers elongate within tissue-like bundles. These bundles were entrained by twisting fiber tips and consolidated by adhesion of a cotton fiber middle lamella (CFML). The fiber bundles consolidated via the CFML ultimately formed a packet of fiber around each seed, which helps explain how thousands of cotton fibers achieve their great length within a confined space. The cell wall nature of the CFML was characterized using transmission electron microscopy, including polymer epitope labeling. Toward the end of elongation, up-regulation occurred in gene expression and enzyme activities related to cell wall hydrolysis, and targeted breakdown of the CFML restored fiber individuality. At the same time, losses occurred in certain cell wall polymer epitopes (as revealed by comprehensive microarray polymer profiling) and sugars within noncellulosic matrix components (as revealed by gas chromatography-mass spectrometry analysis of derivatized neutral and acidic glycosyl residues). Broadly, these data show that adhesion modulated by an outer layer of the primary wall can coordinate the extensive growth of a large group of cells and illustrate dynamic changes in primary wall structure and composition occurring during the differentiation of one cell type that spends only part of its life as a tissue. PMID:19369592

Singh, Bir; Avci, Utku; Eichler Inwood, Sarah E; Grimson, Mark J; Landgraf, Jeff; Mohnen, Debra; Sørensen, Iben; Wilkerson, Curtis G; Willats, William G T; Haigler, Candace H

2009-06-01

79

Layers  

NASA Astrophysics Data System (ADS)

The temperature-dependent photoresponse characteristics of MnAl2S4 layers have been investigated, for the first time, by use of photocurrent (PC) spectroscopy. Three peaks were observed at all temperatures. The electronic origin of these peaks was associated with band-to-band transitions from the valence-band states ?4( z), ?5( x), and ?5( y) to the conduction-band state ?1( s). On the basis of the relationship between PC-peak energy and temperature, the optical band gap could be well expressed by the expression E g( T) = E g(0) - 2.80 × 10-4 T 2/(287 + T), where E g(0) was estimated to be 3.7920 eV, 3.7955 eV, and 3.8354 eV for the valence-band states ?4( z), ?5( x), and ?5( y), respectively. Results from PC spectroscopy revealed the crystal-field and spin-orbit splitting were 3.5 meV and 39.9 meV. The gradual decrease of PC intensity with decreasing temperature can be explained on the basis of trapping centers associated with native defects in the MnAl2S4 layers. Plots of log J ph, the PC current density, against 1/ T, revealed a dominant trap level in the high-temperature region. By comparing PC and the Hall effect results, we confirmed that this trap level is a shallow donor 18.9 meV below the conduction band.

Hong, K. J.; Jeong, T. S.; Youn, C. J.

2014-09-01

80

Germ-cell origin in the adult caecilian Ichthyophis glutinosus (Linn)  

Microsoft Academic Search

In Ichthyophis glutinosus, no residual spermatogonia traceable to primordial germ cells of the embryo are seen, the primary spermatogonia of each season being formed afresh. Their only source so far as the adult is concerned, is the lining of the collecting duct and its numerous branches which ramify in the testis. No evidences of their origin from the surface epithelial

B. R. Seshachar

1937-01-01

81

TrkB-Like Immunoreactivity Is Present on Geniculocortical Afferents in Layer IV of Kitten Primary Visual Cortex  

PubMed Central

Exogenous administration of the neurotrophins brain-derived neurotrophic factor (BDNF) or neurotrophin-4/5 (NT-4/5), or blockade of their endogenous actions, have been reported to affect the anatomic organization and physiological responses of neurons in developing mammalian primary visual cortex. Experimental alteration of levels of these neurotrophic factors can also influence the morphology of the geniculocortical afferents that project from the lateral geniculate nucleus (LGN) to primary visual cortex. BDNF and NT-4/5 are ligands of the TrkB tyrosine kinase receptor. Although multiple populations of cortical neurons express TrkB, it is not known whether geniculocortical afferents express this receptor on their axon branches in visual cortex. We have anatomically labeled geniculocortical afferents of postnatal day 40 kittens with the anterograde neuronal tracer Phaseolus vulgaris leucoagglutinin (PHA-L) and performed double-label immunofluorescence with a panel of anti-TrkB antibodies. Confocal microscopy and object-based colocalization analysis were used to measure levels of TrkB-like immunoreactivity (IR) on geniculocortical afferents in layer IV of primary visual cortex. By using a conservative analysis involving a comparison of measured colocalization with the amount of colocalization expected based on random overlap of TrkB puncta and PHA-L-labeled afferents, 3 of 5 anti-TrkB antibodies tested showed significant colocalization with the geniculocortical axons. Results for the other two antibodies were indeterminate. The indices obtained for colocalization of TrkB and geniculocortical afferents were also compared with the equivalent index obtained for GAD65, a protein that has a similar overall expression pattern to that of TrkB but is not expressed on geniculocortical axons. This analysis indicated that TrkB was present on geniculocortical axons for all five TrkB antibodies tested. TrkB-like IR was also observed on neuronal somata in the LGN. These results indicate that TrkB receptors on geniculocortical afferents are potential mediators of the actions of BDNF and NT-4/5 in developing visual cortex. PMID:11447584

SILVER, MICHAEL A.; STRYKER, MICHAEL P.

2008-01-01

82

Germ tube induction in Candida albicans.  

PubMed

A reproducible and simple system for the production of germ tubes from yeast cells of Candida albicans using glucose and glutamine as substrates has been described. During germ tube formation there was a doubling of the dry weight but the number of cells remained constant. Although the DNA content did not change for the first 4 h of germ tube formation, the RNA content more than doubled. The DNA and RNA content of C. albicans blastospores are 4.5 x 10(-15) g per cell and 48 x 10(-15) g per cell respectively. Nystatin, phenethyl alcohol, 2,4-dinitrophenol, azaserine, salicylhydroxamic acid, and 5-fluorocytosine were all effective inhibitors of germ tube formation. Cysteine, potassium cyanide, and polyoxin D did not prevent germination. The incorporation of both uracil and leucine occurred rapidly during germ tube formation. The inhibitors of RNA synthesis, actinomycin D. cordycepin, and daunomycin prevented germination and inhibited uracil incorporation. The translational inhibitors, trichodermin, aurin tricarboxylic acid, puromycin, and cyloheximide were effective in inhibiting both germ tube formation and leucine incorporation. PMID:6996798

Shepherd, M G; Yin, C Y; Ram, S P; Sullivan, P A

1980-01-01

83

Seasonal variability of primary production and phytoplankton biomass in the western Pacific subarctic gyre: Control by light availability within the mixed layer  

NASA Astrophysics Data System (ADS)

A distinct seasonal variation of primary production was revealed from shipboard observations conducted from 2005 to 2013 at time series station K2 in the western Pacific subarctic gyre (WSG). The mean depth-integrated primary production was highest (569 ± 162 mg C m-2 d-1) in summer and lowest (101 ± 16 mg C m-2 d-1) in winter. Strong winter mixing enriched the mixed layer (ML) with nutrients that were not fully consumed during the remainder of the year, the result being that the WSG was a high-nutrient, low-chlorophyll (HNLC) region. The deep ML reduced primary production by reducing light availability in winter, whereas primary production was enhanced by strong light availability in the shallower ML as summer progressed. However, primary production was often attenuated by a reduction of light availability attributable to dense sea fog in summer. We found a significant relationship between primary production and light availability in this HNLC region. However, chlorophyll a was less variable seasonally than primary production. The highest depth-integrated chlorophyll a was observed in summer (54.6 ± 13.4 mg m-2), but chlorophyll a remained high in winter (45.3 ± 7.7 mg m-2). Reduced light availability depressed primary production, but a reduction of the chlorophyll a concentration was prevented by a relaxation of grazing in the deep ML during winter. We found that light availability exerted an important control on the seasonal variability of primary production and phytoplankton biomass in the WSG.

Matsumoto, Kazuhiko; Honda, Makio C.; Sasaoka, Kosei; Wakita, Masahide; Kawakami, Hajime; Watanabe, Shuichi

2014-09-01

84

Surgery and Combination Chemotherapy in Treating Children With Extracranial Germ Cell Tumors  

ClinicalTrials.gov

Childhood Embryonal Tumor; Childhood Extracranial Germ Cell Tumor; Childhood Extragonadal Germ Cell Tumor; Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Childhood Teratoma; Ovarian Embryonal Carcinoma; Ovarian Yolk Sac Tumor; Stage II Malignant Testicular Germ Cell Tumor; Stage IIA Ovarian Germ Cell Tumor; Stage IIB Ovarian Germ Cell Tumor; Stage IIC Ovarian Germ Cell Tumor; Stage III Malignant Testicular Germ Cell Tumor; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIC Ovarian Germ Cell Tumor; Testicular Choriocarcinoma and Yolk Sac Tumor; Testicular Embryonal Carcinoma

2015-03-04

85

Histologically confirmed intracranial germ cell tumors; an analysis of 62 patients in a single institute  

Microsoft Academic Search

This study was undertaken to document the clinicopathologic characteristics of histologically verified, primary intracranial\\u000a germ cell tumors (GCTs), determine treatment outcomes, and to identify prognostic factors. The records of 62 patients (45\\u000a males and 17 females) with a primary intracranial GCT were retrospectively analyzed. Mean patient age was 18 years, and median\\u000a follow-up was 41 months. The most common histological subtypes were

Dakeun Lee; Yeon-Lim Suh

2010-01-01

86

"Life in a Germ-Free World":  

PubMed Central

Summary: This article examines a specific technology, the germ-free "isolator," tracing its development across three sites: (1) the laboratory for the production of standard laboratory animals, (2) agriculture for the efficient production of farm animals, and (3) the hospital for the control and prevention of cross-infection and the protection of individuals from infection. Germ-free technology traveled across the laboratory sciences, clinical and veterinary medicine, and industry, yet failed to become institutionalized outside the laboratory. That germ-free technology worked was not at issue. Working, however, was not enough. Examining the history of a technology that failed to find widespread application reveals the labor involved in aligning cultural, societal, and material factors necessary for successful medical innovation. PMID:23000838

Kirk, Robert G. W.

2012-01-01

87

Primary yolk sac tumor of the cerebellar vermis: a case report.  

PubMed

Extragonadal germ cell tumors are rare and comprise 2-5% of all germ cell tumors. Seminoma/dysgerminoma, teratoma, yolk sac tumor (YST) and mixed germ cell tumors are few of the extragonadal germ cell tumors arising within the brain. Of these, primary pure YSTs arising in the brain are extremely rare and arise in the pineal (62%) and suprasellar (31%) regions. Primary YST occurring in the cerebellum is exceedingly rare, associated with a very poor prognosis and has been reported in less than 10 cases in literature. We herein report a case of primary pure yolk sac tumor in the cerebellar vermis in a 2-year-old child. PMID:24943765

Shenoy, Asha S; Desai, Heena M; Tyagi, Devendra K; Savant, Hemant V; Kavishwar, Vikas S; Balasubramaniam, Meenakshi

2014-01-01

88

Treatment Options By Stage (Ovarian Germ Cell Tumors)  

MedlinePLUS

Treatment Options By Stage Stage I Ovarian Germ Cell Tumors Treatment depends on whether the tumor is ... the NCI Web site . Stage II Ovarian Germ Cell Tumors Treatment depends on whether the tumor is ...

89

[Studies on primary aromatic amines (PAAs) migration from multi-layer plastic food packaging by HPLC method].  

PubMed

The aim of this study was to identify of primary aromatic amines (PAAs) and to determine their migration from plastic food packaging. The magnitude of the migration of these substances from plastic food packaging consists a base for the evaluation of their compliance with the requirements of EU legislation and hazard for human health taking into account their migration into food. The unprinted and printed multi-layer plastic packaging (laminates), domestic and imported, were examined in these studies. PAAs migration tests from the laminates into food simulant (3% acetic acid) was performed according to the appropriate procedures recommended in the EU for testing migration from food contact articles under standard conditions reflecting the real use of laminates (10 days, 40 degrees C) and under ,, worst case scenario" conditions (2 h, 70 degrees C). PAAs present in migration solutions were concentrated on SPE columns and then seven PAAs (aniline, 1,3-phenylenediamine, 2, 6-toluenediamine, 2,4-toluenediamine, 4,4'-oxydianiline, 4,4'-methylenedianiline and 3,3 '-dimethylbenzidyne) were identified and determined by previously validated HPLC-DAD method. Depending on the migration conditions the PAAs content was different. When the "worst case scenario" conditions were applied the migration of 4,4 '-methylenedianiline (4,4 '-MDA) ranged from below detection limit (LOD = 0.51 microg/kg) up to 9.86 microg/kg, and aniline was released in the range from below detection limit (LOD = 0,98 microg/kg) up to 7.04 microg/kg. In two laminate samples of eight examined, the sum of PAAs (aniline and 4,4'-MDA) was 13.32 microg/kg and 14.72 microg/kg showing that the permitted limit (10 microg/kg) was exceeded. In the standard conditions, the migration of aniline and 4,4'-MDA was significantly lower Regarding the carcinogenic potential of PAAs, the laminates causing the amines migration above the permitted limit should not be used as food packaging. PMID:22435290

Cwiek-Ludwicka, Kazimiera; Pawlicka, Marzena; Starski, Andrzej; Pó?torak, Hanna; Kar?owski, Kazimierz

2011-01-01

90

Galactic Cosmic Ray Event-Based Risk Model (GERM) Code  

NASA Technical Reports Server (NTRS)

This software describes the transport and energy deposition of the passage of galactic cosmic rays in astronaut tissues during space travel, or heavy ion beams in patients in cancer therapy. Space radiation risk is a probability distribution, and time-dependent biological events must be accounted for physical description of space radiation transport in tissues and cells. A stochastic model can calculate the probability density directly without unverified assumptions about shape of probability density function. The prior art of transport codes calculates the average flux and dose of particles behind spacecraft and tissue shielding. Because of the signaling times for activation and relaxation in the cell and tissue, transport code must describe temporal and microspatial density of functions to correlate DNA and oxidative damage with non-targeted effects of signals, bystander, etc. These are absolutely ignored or impossible in the prior art. The GERM code provides scientists data interpretation of experiments; modeling of beam line, shielding of target samples, and sample holders; and estimation of basic physical and biological outputs of their experiments. For mono-energetic ion beams, basic physical and biological properties are calculated for a selected ion type, such as kinetic energy, mass, charge number, absorbed dose, or fluence. Evaluated quantities are linear energy transfer (LET), range (R), absorption and fragmentation cross-sections, and the probability of nuclear interactions after 1 or 5 cm of water equivalent material. In addition, a set of biophysical properties is evaluated, such as the Poisson distribution for a specified cellular area, cell survival curves, and DNA damage yields per cell. Also, the GERM code calculates the radiation transport of the beam line for either a fixed number of user-specified depths or at multiple positions along the Bragg curve of the particle in a selected material. The GERM code makes the numerical estimates of basic physical and biophysical quantities of high-energy protons and heavy ions that have been studied at the NASA Space Radiation Laboratory (NSRL) for the purpose of simulating space radiation biological effects. In the first option, properties of monoenergetic beams are treated. In the second option, the transport of beams in different materials is treated. Similar biophysical properties as in the first option are evaluated for the primary ion and its secondary particles. Additional properties related to the nuclear fragmentation of the beam are evaluated. The GERM code is a computationally efficient Monte-Carlo heavy-ion-beam model. It includes accurate models of LET, range, residual energy, and straggling, and the quantum multiple scattering fragmentation (QMSGRG) nuclear database.

Cucinotta, Francis A.; Plante, Ianik; Ponomarev, Artem L.; Kim, Myung-Hee Y.

2013-01-01

91

Germ cell nuclear factor is not required for the down-regulation of pluripotency markers in fetal ovarian germ cells  

E-print Network

In mouse, germ cells retain expression of the pluripotency markers Oct4 and Nanog longer than any other cells in the body. While somatic cells repress these markers during gastrulation, female germ cells continue to express ...

Okumura, Leah M

2012-01-01

92

Characterization of the functional properties of carob germ proteins  

Technology Transfer Automated Retrieval System (TEKTRAN)

Proteins from the carob germ were identified as having gluten-like proteins in 1935. While some biochemical characterization of carob germ proteins and their functionality has been carried out, relatively little has been done when compared to proteins such as gluten. Carob germ proteins were separ...

93

Evaluation of corn germ meal as extender in plywood adhesive  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to evaluate the potential of corn germ meal as protein extender in plywood adhesive. Partially defatted dried corn germ, containing 2.1% (dry basis, db) crude oil and 24.7% (db) crude protein, was ground to 40-mesh particle size. The corn germ meal was then substituted (on...

94

Metformin Hydrochloride, Carboplatin, and Paclitaxel in Treating Patients With Recurrent Ovarian, Fallopian Tube, or Primary Peritoneal Cancer  

ClinicalTrials.gov

Ovarian Papillary Serous Carcinoma; Ovarian Serous Cystadenocarcinoma; Recurrent Fallopian Tube Cancer; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Primary Peritoneal Cavity Cancer

2014-01-28

95

Germ-line transformation of Arabidopsis lasiocarpa  

Microsoft Academic Search

In planta transformation methods have opened up the possibility of transforming plant species for which no regeneration protocols currently exist. In this study, the suitability of the germ-line transformation method developed for Arabidopsis thaliana was examined for four taxa in the Brassicaceae that have not been previously transformed: Arabidopsis griffithiana, Arabidopsis lasiocarpa, Arabidopsis petraea and Capsella bursa-pastoris. Numerous transformants were

Brian W. Tague

2001-01-01

96

UTILIZING CORN GERM MEAL IN PLYWOOD GLUE  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to evaluate the potential of corn germ meal as protein extender in plywood adhesive. This research is part of our laboratory’s efforts to develop new uses for the proteinaceous co-products from cereal and soybean processing. We were previously successful in formulating a s...

97

Colleges Put the Squeeze on Germs  

ERIC Educational Resources Information Center

A spirited campaign to promote "hand hygiene" is under way at the University of Central Florida Orlando campus, and the urinal toter, known as UCF 5th Guy, is its front line. Like their counterparts at many other institutions, health officials at Central Florida want students to think about the germs that lurk on their hands. And then clean them,…

Sander, Libby

2008-01-01

98

Clinical epidemiology of testicular germ cell tumors  

Microsoft Academic Search

Clinical epidemiology is sometimes called the basic science of clinical medicine. In terms of the pathogenesis of testicular germ cell tumors (GCTs), clinical epidemiology analyzes suspected risk factors. The present review highlights the risk factors established so far and briefly summarizes those factors currently under investigation. In analogy to the methods of evidence based medicine, this review attributes levels of

K.-P. Dieckmann; U. Pichlmeier

2004-01-01

99

Extraction and demulsification of oil from wheat germ, barley germ, and rice bran using an aqueous enzymatic method  

Technology Transfer Automated Retrieval System (TEKTRAN)

An aqueous enzymatic method was developed to extract oil from wheat germ. The parameters that influence oil yield were investigated, including wheat germ pretreatment, comparison of various industrial enzymes, pH, ratio of wheat germ to water, reaction time and demulsification. Pretreatment at 180ºC...

100

From the Cover: Development without germ cells: The role of the germ line in zebrafish sex differentiation  

Microsoft Academic Search

The progenitors of the gametes, the primordial germ cells (PGCs) are typically specified early in the development in positions, which are distinct from the gonad. These cells then migrate toward the gonad where they differentiate into sperms and eggs. Here, we study the role of the germ cells in somatic development and particularly the role of the germ line in

Krasimir Slanchev; Jürg Stebler; Guillermo de La Cueva-Méndez; Erez Raz

2005-01-01

101

A Feedforward Inhibitory Circuit Mediates Lateral Refinement of Sensory Representation in Upper Layer 2/3 of Mouse Primary Auditory Cortex  

PubMed Central

Sensory information undergoes ordered and coordinated processing across cortical layers. Whereas cortical layer (L) 4 faithfully acquires thalamic information, the superficial layers appear well staged for more refined processing of L4-relayed signals to generate corticocortical outputs. However, the specific role of superficial layer processing and how it is specified by local synaptic circuits remains not well understood. Here, in the mouse primary auditory cortex, we showed that upper L2/3 circuits play a crucial role in refining functional selectivity of excitatory neurons by sharpening auditory tonal receptive fields and enhancing contrast of frequency representation. This refinement is mediated by synaptic inhibition being more broadly recruited than excitation, with the inhibition predominantly originating from interneurons in the same cortical layer. By comparing the onsets of synaptic inputs as well as of spiking responses of different types of neuron, we found that the broadly tuned, fast responding inhibition observed in excitatory cells can be primarily attributed to feedforward inhibition originating from parvalbumin (PV)-positive neurons, whereas somatostatin (SOM)-positive interneurons respond much later compared with the onset of inhibitory inputs to excitatory neurons. We propose that the feedforward circuit-mediated inhibition from PV neurons, which has an analogous function to lateral inhibition, enables upper L2/3 excitatory neurons to rapidly refine auditory representation. PMID:25297094

Li, Ling-yun; Ji, Xu-ying; Liang, Feixue; Li, Ya-tang; Xiao, Zhongju

2014-01-01

102

A feedforward inhibitory circuit mediates lateral refinement of sensory representation in upper layer 2/3 of mouse primary auditory cortex.  

PubMed

Sensory information undergoes ordered and coordinated processing across cortical layers. Whereas cortical layer (L) 4 faithfully acquires thalamic information, the superficial layers appear well staged for more refined processing of L4-relayed signals to generate corticocortical outputs. However, the specific role of superficial layer processing and how it is specified by local synaptic circuits remains not well understood. Here, in the mouse primary auditory cortex, we showed that upper L2/3 circuits play a crucial role in refining functional selectivity of excitatory neurons by sharpening auditory tonal receptive fields and enhancing contrast of frequency representation. This refinement is mediated by synaptic inhibition being more broadly recruited than excitation, with the inhibition predominantly originating from interneurons in the same cortical layer. By comparing the onsets of synaptic inputs as well as of spiking responses of different types of neuron, we found that the broadly tuned, fast responding inhibition observed in excitatory cells can be primarily attributed to feedforward inhibition originating from parvalbumin (PV)-positive neurons, whereas somatostatin (SOM)-positive interneurons respond much later compared with the onset of inhibitory inputs to excitatory neurons. We propose that the feedforward circuit-mediated inhibition from PV neurons, which has an analogous function to lateral inhibition, enables upper L2/3 excitatory neurons to rapidly refine auditory representation. PMID:25297094

Li, Ling-yun; Ji, Xu-ying; Liang, Feixue; Li, Ya-tang; Xiao, Zhongju; Tao, Huizhong W; Zhang, Li I

2014-10-01

103

Tocopherols and tocotrienols in barley oil prepared from germ and other fractions from scarification and sieving of hulless barley  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two cultivars of hulless barley (Doyce and Merlin), were scarified to abrade the outer layers of the kernels (germ, pericarp, and aleurone). The resulting scarification fines fractions were then separated into four particle size subfractions using sieves. Each of the size subfractions was then extr...

104

Second non-germ cell malignancies after radiotherapy of testicular cancer with or without chemotherapy  

Microsoft Academic Search

The incidence of a new primary non-germ cell malignancy was determined in 876 patients with testicular cancer treated at the Norwegian Radium Hospital from 1956 to 1977. Sixty-five patients developed a second cancer leading to a statistically significant increased relative risk (RR = 1.58), especially if extended radiotherapy had been given (RR = 4.13). The excess risks of developing lung

SD Fosså; F Langmark; N Aass; A Andersen; R Lothe; AL Børresen

1990-01-01

105

Intracranial Germ Cell Tumors in Children: An Immunohistochemical and Electron Microscopic Study  

Microsoft Academic Search

From a review of a series of 1,474 intracranial tumors occurring in children, we identified 49 patients (3.3 %) with primary intracranial germ cell tumors: 65% germinomatous, 26% nongerminomatous (8 teratomas, 3 endodermal sinus, and 2 choriocarcinomas), and 8°10 mixed. Placental alkaline phosphatase was present in all germinomas tested. Human chorionic gonadotropin was identified in 7 patients, cytokeratin in 6,

Ignacio Felix; Laurence E. Becker

1991-01-01

106

Germ Cell Development in the Scleractinian Coral Euphyllia ancora (Cnidaria, Anthozoa)  

PubMed Central

Sexual reproduction of scleractinian coral is among the most important means of establishing coral populations. However, thus far, little is known about the mechanisms underlying coral gametogenesis. To better understand coral germ cell development, we performed a histological analysis of gametogenesis in Euphyllia ancora and characterized the coral homolog of the Drosophila germline marker gene vasa. The histological analysis revealed that E. ancora gametogenesis occurs in the mesenterial mesoglea between the mesenterial filaments and the retractor muscle bands. The development of germ cells takes approximately one year in females and half a year in males. Staining of tissue sections with an antibody against E. ancora Vasa (Eavas) revealed anti-Eavas immunoreactivity in the oogonia, early oocyte, and developing oocyte, but only faint or undetectable reactivity in developing oocytes that were >150 µm in diameters. In males, Eavas could be detected in the spermatogonia and primary spermatocytes but was only faintly detectable in the secondary spermatocytes, spermatids, and sperms. Furthermore, a reverse transcription-polymerase chain reaction analysis and Western blotting analysis of unfertilized mature eggs proved the presence of Eavas transcripts and proteins, suggesting that Eavas may be a maternal factor. Vasa may represent a germ cell marker for corals, and would allow us to distinguish germ cells from somatic cells in coral bodies that have no distinct organs. PMID:22848529

Shikina, Shinya; Chen, Chieh-Jhen; Liou, Jhe-Yu; Shao, Zi-Fan; Chung, Yi-Jou; Lee, Yan-Horn; Chang, Ching-Fong

2012-01-01

107

Mechanisms controlling primary and new production in a global ecosystem model Part I: The role of the large-scale upper mixed layer variability  

NASA Astrophysics Data System (ADS)

A global general circulation model coupled to a simple six-compartment ecosystem model is used to study the extent to which global variability in primary and export production can be realistically predicted on the basis of advanced parameterizations of upper mixed layer physics, without recourse to introducing extra complexity in model biology. The ''K profile parameterization'' (KPP) scheme employed, combined with 6-hourly external forcing, is able to capture short-term periodic and episodic events such as diurnal cycling and storm-induced deepening. The model realistically reproduces various features of global ecosystem dynamics that have been problematic in previous global modelling studies, using a single generic parameter set. The realistic simulation of deep convection in the North Atlantic, and lack of it in the North Pacific and Southern Oceans, leads to good predictions of chlorophyll and primary production in these contrasting areas. Realistic levels of primary production are predicted in the oligotrophic gyres due to high frequency external forcing of the upper mixed layer (accompanying paper Popova et al., 2006) and novel parameterizations of zooplankton excretion. Good agreement is shown between model and observations at various JFOFS time series sites: BATS, KERFIX, Papa and station India. One exception is that the high zooplankton grazing rates required to maintain low chlorophyll in high-nutrient low-chlorophyll and oligotrophic systems lessened agreement between model and data in the northern North Atlantic, where mesozooplankton with lower grazing rates may be dominant. The model is therefore not globally robust in the sense that additional parameterizations were needed to realistically simulate ecosystem dynamics in the North Atlantic. Nevertheless, the work emphasises the need to pay particular attention to the parameterization of mixed layer physics in global ocean ecosystem modelling as a prerequisite to increasing the complexity of ecosystem models.

Popova, E. E.; Coward, A. C.; Nurser, G. A.; de Cuevas, B.; Fasham, M. J. R.; Anderson, T. R.

2006-07-01

108

Standard-Dose Combination Chemotherapy or High-Dose Combination Chemotherapy and Stem Cell Transplant in Treating Patients With Relapsed or Refractory Germ Cell Tumors  

ClinicalTrials.gov

Germ Cell Tumor; Teratoma; Choriocarcinoma; Germinoma; Mixed Germ Cell Tumor; Yolk Sac Tumor; Childhood Teratoma; Malignant Germ Cell Neoplasm; Extragonadal Seminoma; Non-seminomatous Germ Cell Tumor; Seminoma

2015-03-24

109

A role for Lin28 in primordial germ cell development and germ cell malignancy  

PubMed Central

The rarity and inaccessibility of the earliest primordial germ cells (PGCs) in the mouse embryo thwarts efforts to investigate molecular mechanisms of germ cell specification. Stella marks the minute founder population of the germ lineage1,2. Here we differentiate mouse embryonic stem cells (ESCs) carrying a Stella transgenic reporter into putative PGCs in vitro. The Stella+ cells possess a transcriptional profile similar to embryo-derived PGCs, and like their counterparts in vivo, lose imprints in a time-dependent manner. Using inhibitory RNAs to screen candidate genes for effects on the development of Stella+ cells in vitro, we discovered that Lin28, a negative regulator of let-7 microRNA processing3-6, is essential for proper PGC development. We further show that Blimp1, a let-7 target and a master regulator of PGC specification7-9, can rescue the effect of Lin28-deficiency during PGC development, thereby establishing a mechanism of action for Lin28 during PGC specification. Over-expression of Lin28 promotes formation of Stella+ cells in vitro and PGCs in chimeric embryos, and is associated with human germ cell tumours. The differentiation of putative PGCs from ESCs in vitro recapitulates the early stages of gamete development in vivo, and provides an accessible system for discovering novel genes involved in germ cell development and malignancy. PMID:19578360

West, Jason A.; Viswanathan, Srinivas R.; Yabuuchi, Akiko; Cunniff, Kerianne; Takeuchi, Ayumu; Park, In-Hyun; Sero, Julia E.; Zhu, Hao; Perez-Atayde, Antonio; Frazier, A. Lindsay; Surani, M. Azim; Daley, George Q.

2009-01-01

110

Measuring cell adhesion forces of primary gastrulating cells from zebrafish using atomic force microscopy.  

PubMed

During vertebrate gastrulation, progenitor cells of different germ layers acquire specific adhesive properties that contribute to germ layer formation and separation. Wnt signals have been suggested to function in this process by modulating the different levels of adhesion between the germ layers, however, direct evidence for this is still lacking. Here we show that Wnt11, a key signal regulating gastrulation movements, is needed for the adhesion of zebrafish mesendodermal progenitor cells to fibronectin, an abundant extracellular matrix component during gastrulation. To measure this effect, we developed an assay to quantify the adhesion of single zebrafish primary mesendodermal progenitors using atomic-force microscopy (AFM). We observed significant differences in detachment force and work between cultured mesendodermal progenitors from wild-type embryos and from slb/wnt11 mutant embryos, which carry a loss-of-function mutation in the wnt11 gene, when tested on fibronectin-coated substrates. These differences were probably due to reduced adhesion to the fibronectin substrate as neither the overall cell morphology nor the cell elasticity grossly differed between wild-type and mutant cells. Furthermore, in the presence of inhibitors of fibronectin-integrin binding, such as RGD peptides, the adhesion force and work were strongly decreased, indicating that integrins are involved in the binding of mesendodermal progenitors in our assay. These findings demonstrate that AFM can be used to quantitatively determine the substrate-adhesion of cultured primary gastrulating cells and provide insight into the role of Wnt11 signalling in modulating cell adhesion at the single cell scale. PMID:16155253

Puech, Pierre-Henri; Taubenberger, Anna; Ulrich, Florian; Krieg, Michael; Muller, Daniel J; Heisenberg, Carl-Philipp

2005-09-15

111

A process for the aqueous enzymatic extraction of corn oil from dry-milled corn germ and enzymatic wet milled corn germ (E-Germ)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Previously, we reported an aqueous enzymatic oil extraction process that achieved oil yields of 80-90% using corn germ from a commercial corn wet mill. Three commercial cellulases were reported to result in similar oil yields when wet milles corn germ was used as a feedstock in this process. When ...

112

Spike Firing and IPSPs in Layer V Pyramidal Neurons during Beta Oscillations in Rat Primary Motor Cortex (M1) In Vitro  

PubMed Central

Beta frequency oscillations (10–35 Hz) in motor regions of cerebral cortex play an important role in stabilising and suppressing unwanted movements, and become intensified during the pathological akinesia of Parkinson's Disease. We have used a cortical slice preparation of rat brain, combined with concurrent intracellular and field recordings from the primary motor cortex (M1), to explore the cellular basis of the persistent beta frequency (27–30 Hz) oscillations manifest in local field potentials (LFP) in layers II and V of M1 produced by continuous perfusion of kainic acid (100 nM) and carbachol (5 µM). Spontaneous depolarizing GABA-ergic IPSPs in layer V cells, intracellularly dialyzed with KCl and IEM1460 (to block glutamatergic EPSCs), were recorded at ?80 mV. IPSPs showed a highly significant (P< 0.01) beta frequency component, which was highly significantly coherent with both the Layer II and V LFP oscillation (which were in antiphase to each other). Both IPSPs and the LFP beta oscillations were abolished by the GABAA antagonist bicuculline. Layer V cells at rest fired spontaneous action potentials at sub-beta frequencies (mean of 7.1+1.2 Hz; n?=?27) which were phase-locked to the layer V LFP beta oscillation, preceding the peak of the LFP beta oscillation by some 20 ms. We propose that M1 beta oscillations, in common with other oscillations in other brain regions, can arise from synchronous hyperpolarization of pyramidal cells driven by synaptic inputs from a GABA-ergic interneuronal network (or networks) entrained by recurrent excitation derived from pyramidal cells. This mechanism plays an important role in both the physiology and pathophysiology of control of voluntary movement generation. PMID:24465488

Lacey, Michael G.; Gooding-Williams, Gerard; Prokic, Emma J.; Yamawaki, Naoki; Hall, Stephen D.; Stanford, Ian M.; Woodhall, Gavin L.

2014-01-01

113

Changes in Brain Function in Patients With Stage I, Stage II, Stage III, or Stage IV Ovarian, Primary Peritoneal, or Fallopian Tube Cancer Who Are Receiving Chemotherapy  

ClinicalTrials.gov

Cognitive Side Effects of Cancer Therapy; Malignant Ovarian Mixed Epithelial Tumor; Malignant Ovarian Surface Epithelial-Stromal Tumor; Ovarian Brenner Tumor; Ovarian Carcinosarcoma; Ovarian Choriocarcinoma; Ovarian Clear Cell Cystadenocarcinoma; Ovarian Dysgerminoma; Ovarian Embryonal Carcinoma; Ovarian Endometrioid Adenocarcinoma; Ovarian Mixed Germ Cell Tumor; Ovarian Mucinous Cystadenocarcinoma; Ovarian Polyembryoma; Ovarian Sarcoma; Ovarian Serous Cystadenocarcinoma; Ovarian Teratoma; Ovarian Yolk Sac Tumor; Stage I Ovarian Cancer; Stage IA Fallopian Tube Cancer; Stage IA Ovarian Cancer; Stage IA Ovarian Germ Cell Tumor; Stage IB Fallopian Tube Cancer; Stage IB Ovarian Cancer; Stage IB Ovarian Germ Cell Tumor; Stage IC Fallopian Tube Cancer; Stage IC Ovarian Cancer; Stage IC Ovarian Germ Cell Tumor; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIA Ovarian Cancer; Stage IIA Ovarian Germ Cell Tumor; Stage IIB Fallopian Tube Cancer; Stage IIB Ovarian Cancer; Stage IIB Ovarian Germ Cell Tumor; Stage IIC Fallopian Tube Cancer; Stage IIC Ovarian Cancer; Stage IIC Ovarian Germ Cell Tumor; Stage IIIA Fallopian Tube Cancer; Stage IIIA Ovarian Cancer; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIA Primary Peritoneal Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIB Ovarian Cancer; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIB Primary Peritoneal Cancer; Stage IIIC Fallopian Tube Cancer; Stage IIIC Ovarian Cancer; Stage IIIC Ovarian Germ Cell Tumor; Stage IIIC Primary Peritoneal Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Ovarian Germ Cell Tumor; Stage IV Primary Peritoneal Cancer; Undifferentiated Ovarian Carcinoma

2014-12-23

114

Aging and the Germ Line: Where Mortality and Immortality Meet  

Microsoft Academic Search

Germ cells are highly specialized cells that form gametes, and they are the only cells within an organism that contribute\\u000a genes to offspring. Germline stem cells (GSCs) sustain gamete production, both oogenesis (egg production) and spermatogenesis\\u000a (sperm production), in many organisms. Since the genetic information contained within germ cells is passed from generation\\u000a to generation, the germ line is often

D. Leanne Jones

2007-01-01

115

Entry of Mouse Embryonic Germ Cells into Meiosis  

Microsoft Academic Search

Germ cells harvested from mouse embryonic genital ridges were mixed with disaggregated embryonic lung cells, and the reaggregates were cultured for 4–7 days. Germ cells derived from female embryos 10.5–13.5 days postcoitum (dpc) entered and progressed through meiotic prophasein vitroasin vivo,although with a 12- to 24-hr delay. If the cultures were maintained for 2–3 weeks, the germ cells developed into

A. McLaren; D. Southee

1997-01-01

116

Embryonic stem cells can form germ cells in vitro  

Microsoft Academic Search

Knock-in embryonic stem (ES) cells, in which GFP or lacZ was expressed from the endogenous mouse vasa homolog (Mvh), which is specifically expressed in differentiating germ cells, were used to visualize germ cell production during in vitro differentiation. The appearance of MVH-positive germ cells depended on embryoid body formation and was greatly enhanced by the inductive effects of bone morphogenic

Yayoi Toyooka; Naoki Tsunekawa; Ryuko Akasu; Toshiaki Noce

2003-01-01

117

Mixed germ cell tumor of ovary and clitoromegaly in Swyer's syndrome: a case report.  

PubMed

Swyer syndrome is a type of pure gonadal dysgenesis correlating with 46 XY karyotype, primary amenorrhea, and female internal and external genitalia. It reveals a testicular differentiation abnormality.A 16-year old girl admitted to our center with primary amenorrhea and abdominal mass. In spite of the absence of normal testis, clitoromegaly was noticed. Peripheral blood karyotype analysis showed 46 XY. Histopathology of the excised gonads determined mixed germ cell tumor in right ovary and streak left gonad without gonadoblastoma in left side. In patients suffering from Swyer syndrome, high risk of gonadal neoplasia dictates early prophylactic gonadal excision to lengthen survival. PMID:22773216

Aminimoghaddam, S; Mokri, B; Mahmoodzadeh, F

2012-07-01

118

The sensitivity of primary productivity to intra-seasonal mixed layer variability in the sub-Antarctic Zone of the Atlantic Ocean  

NASA Astrophysics Data System (ADS)

The seasonal cycle of primary productivity is impacted by seasonal and intra-seasonal dynamics of the mixed layer through the changing balance between mixing and buoyancy forcing, which regulates nutrient supply and light availability. Of particular recent interest is the role of synoptic scale events in supplying nutrients, particularly iron, to the euphotic zone in the Sub Antarctic Zone (SAZ), where phytoplankton blooms occur throughout summer. In this study, we present high resolution measurements of net community production (NCP) constrained by ?O2/Ar ratios, and mixed layer depth (MLD) in the Atlantic SAZ. We found a non-linear relationship between NCP and MLD, with the highest and most variable NCP observed in shallow MLDs (< 45 m). We propose that NCP variability in the SAZ may be driven by alternating states of synoptic-scale deepening of the mixed layer, leading to the entrainment of iron (dFe), followed by restratification, allowing rapid growth in an iron replete, high light environment. Synoptic iron fluxes into the euphotic zone based on water column dFe profiles and high resolution glider MLD data, reveal a potentially significant contribution of "new iron" which could sustain NCP throughout summer. Future process studies will help elaborate these findings further.

Joubert, W. R.; Swart, S.; Tagliabue, A.; Thomalla, S. J.; Monteiro, P. M. S.

2014-03-01

119

Human primordial germ cell-derived progenitors give rise to neurons and glia in vivo  

SciTech Connect

We derived a cell population from cultured human primordial germ cells from early human embryos. The derivates, termed embryoid body-derived (EBD) cells, displayed an extensive capacity for proliferation and expressed a panel of markers in all three germ layers. Interestingly, EBD cells were also positive for markers of neural stem/progenitor cells, such as nestin and glial fibrillary acidic protein. When these cells were transplanted into the brain cavities of fetal sheep and postnatal NOD-SCID mice or nerve-degenerated tibialis anterior muscles, they readily gave rise to neurons or glial cells. To our knowledge, our data are the first to demonstrate that EBD cells can undergo further neurogenesis under suitable environments in vivo. Hence, with the abilities of extensive expansion, self-renewal, and differentiation, EBD cells may provide a useful donor source for neural stem/progenitor cells to be used in cell-replacement therapies for diseases of the nervous system.

Teng, Yincheng [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)] [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China); Chen, Bin [Center for Developmental Biology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, 1665 Kong Jiang Road, Shanghai 200092 (China)] [Center for Developmental Biology, Xinhua Hospital, School of Medicine, Shanghai Jiao Tong University, 1665 Kong Jiang Road, Shanghai 200092 (China); Tao, Minfang, E-mail: Taomf@126.com [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)] [Department of Gynecology and Obstetrics, The 6th People's Hospital, School of Medicine, Shanghai Jiao Tong University, 600 Yishan Road, Shanghai 200233 (China)

2009-12-18

120

A primary analysis of microwave brightness temperature of lunar surface from Chang-E 1 multi-channel radiometer observation and inversion of regolith layer thickness  

NASA Astrophysics Data System (ADS)

In China's first lunar exploration project, Chang-E 1 (CE-1), a multi-channel microwave radiometer was aboard the satellite, with the purpose of measuring microwave brightness temperature (Tb) from lunar surface and surveying the global distribution of lunar regolith layer thickness. In this paper, the primary 621 tracks of swath data measured by CE-1 microwave radiometer from November 2007 to February 2008 are collected and analyzed. Using the nearest neighbor interpolation to collect the Tb data under the same Sun illumination, global distributions of microwave brightness temperature from lunar surface at lunar daytime and nighttime are constructed. Based on the three-layer media modeling (the top dust-soil, regolith and underlying rock media) for microwave thermal emission of lunar surface, the CE-1 measured Tb and its dependence upon latitude, frequency and FeO + TiO 2 content, etc. are discussed. The CE-1 Tb data at Apollo landing sites are especially chosen for validation and calibration on the basis of available ground measurements. Using the empirical dependence of physical temperature upon the latitude verified by the CE-1 multi-channel Tb data at Apollo landing sites, the global distribution of regolith layer thickness is further inverted from the CE-1 brightness temperature data at 3 GHz channel. Those inversions at Apollo landing sites and the characteristics of regolith layer thickness for lunar maria are well compared with the Apollo in situ measurements and the regolith thickness derived from the Earth-based radar data. Finally, the statistical distribution of regolith thickness is analyzed and discussed.

Fa, Wenzhe; Jin, Ya-Qiu

2010-06-01

121

In vitro culture and transposon-mediated genetic modification of chicken primordial germ cells   

E-print Network

Primordial germ cells (PGCs) are the embryonic precursors of the germ cell lineage. Segregation of the chicken germ line from somatic cells occurs very early in embryonic development. By day two of incubation chicken ...

Macdonald, Joni

2012-06-30

122

Topology of the germ plasm and development of primordial germ cells in inverted amphibian eggs  

NASA Technical Reports Server (NTRS)

Inverted Xenopus eggs have reduced numbers of primordial germ cells (PGCs). The extent of the reduction varies from spawning to spawning. Histologic examination revealed that PGC counts were lowest in inverted eggs which displayed the greatest amount of shift in the vegetal mass of large yolk platelets, although the germ plasm itself always remained localized in the egg's original vegetal hemisphere. Even at blastulation the germ plasm continued to be localized in the egg's original vegetal hemisphere. In many cases, however, it was confined to the periphery of the embryo, which probably accounts for the reduced PGC number in some tadpoles. In other cases it may have been dispersed and therefore not detectable in histologic analyses. Although the altered site of involution in inverted embryos did not influence PGC development, subsequent cell movement patterns apparently did. Those embryos which displayed the largest degree of pattern reversal at the tail-bud stage also exhibited the most extreme reduction in PGC numbers. A brief cold shock (4 degrees C, 10 min) prior to first cleavage leads to a further reduction in PGC numbers in inverted embryos, probably as a result of the displacement of the germ plasm away from its original vegetal pole location.

Wakahara, M.; Neff, A. W.; Malacinski, G. M.

1984-01-01

123

Metformin Hydrochloride and Combination Chemotherapy in Treating Patients With Stage III-IV Ovarian, Fallopian Tube, or Primary Peritoneal Cancer  

ClinicalTrials.gov

Brenner Tumor; Malignant Ascites; Malignant Pleural Effusion; Ovarian Clear Cell Cystadenocarcinoma; Ovarian Endometrioid Adenocarcinoma; Ovarian Mixed Epithelial Carcinoma; Ovarian Serous Cystadenocarcinoma; Ovarian Undifferentiated Adenocarcinoma; Recurrent Fallopian Tube Cancer; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Primary Peritoneal Cavity Cancer; Stage IIIA Fallopian Tube Cancer; Stage IIIA Ovarian Epithelial Cancer; Stage IIIA Ovarian Germ Cell Tumor; Stage IIIA Primary Peritoneal Cavity Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIB Ovarian Epithelial Cancer; Stage IIIB Ovarian Germ Cell Tumor; Stage IIIB Primary Peritoneal Cavity Cancer; Stage IIIC Fallopian Tube Cancer; Stage IIIC Ovarian Epithelial Cancer; Stage IIIC Ovarian Germ Cell Tumor; Stage IIIC Primary Peritoneal Cavity Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Epithelial Cancer; Stage IV Ovarian Germ Cell Tumor; Stage IV Primary Peritoneal Cavity Cancer

2014-04-23

124

The fascinating germ theories on cancer pathogenesis.  

PubMed

For more than 100 years, the germ theory of cancer, proposing that microorganisms were at the origin of the disease, dominated medicine. Several eminent scientists like Etienne Burnet, Mikhail Stepanovich Voronin, Charles-Louis Malassez, and Francis-Peyton Rous argued on the pathogenesis presenting their theories that implicated cocci, fungi and parasites. The impact of these theories was culminated by the Nobel Prize in 1926 that was attributed to the Danish scientist Johannes Fibiger for his work on the nematode Spiroptera as a causative agent in cancer. Even if those theories were the result of fantasy and misinterpretation, they paved the way for the scientific research in oncology. PMID:24659685

Tsoucalas, G; Laios, K; Karamanou, M; Gennimata, V; Androutsos, G

2014-01-01

125

Conserved Role of nanos Proteins in Germ Cell Development  

Microsoft Academic Search

In Drosophila, maternally supplied Nanos functions in the migration of primordial germ cells (PGCs) into the gonad; in mice, zygotic genes are involved instead. We report the cloning and the functional analyses of nanos2 and nanos3 in mice. These genes are differentially expressed in mouse PGCs. nanos2 is predominantly expressed in male germ cells, and the elimination of this gene

Masayuki Tsuda; Yumiko Sasaoka; Makoto Kiso; Kuniya Abe; Seiki Haraguchi; Satoru Kobayashi; Yumiko Saga

2003-01-01

126

EDITORIAL INTRODUCTION [TO FEMALE GERM CELLS: BIOLOGY AND GENETIC RISK  

EPA Science Inventory

This is an editorial introduction to the special issue of utation Research, titled, emale Germ Cells: Biology and Genetic isk, which is an attempt to present a collection of papers that emphasize the distinct properties of female germ cells and their characteristic response to mu...

127

Isolation and transplantation of sturgeon early-stage germ cells.  

PubMed

We report, for the first time, a series of baseline techniques comprising isolation and transplantation of female and male early-stage germ cells in sturgeon to generate a germline chimera as a potential tool for surrogate reproduction and gene banking. Cells were dissociated from testis, characterized by mostly spermatogonia, and from ovary, exclusively comprising oogonia and previtellogenic oocytes, of Acipenser baerii, using 0.3% trypsin (2 hours, 23 °C) dissolved in PBS, isotonic with blood plasma. The dissociated germ cells were sorted by Percoll gradient centrifugation followed by immunolabeling with germ cell-specific vasa antibody DDX4, while 10% to 30% Percoll solution contained 79.4% and 70.8% labeled testicular and ovarian cells. Sorted germ cells were transplanted into a cavity close to a presumptive genital ridge of newly hatched heterospecific Acipenser ruthenus larvae with fluorescein isothiocyanate-labeled endogenous primordial germ cells. The transplanted germ cells were randomly distributed in the body cavity through 30-day posttransplantation (dpt). Subsequently, the cells were organized into genital ridges 50 dpt and proliferated 90 dpt. The number of both transplanted and endogenous germ cells significantly increased from 18.1, 22.2, and 29.1 (30 dpt) to 108.5, 90.8, and 118.5 (90 dpt) in ovarian, testicular, and endogenous germ cells, respectively (P < 0.05). The efficiency of transplantation was 60% (counted 90 dpt). PMID:25559841

Pšeni?ka, Martin; Saito, Taiju; Linhartová, Zuzana; Gazo, Ievgeniia

2015-04-01

128

Pediatric germ cell tumors presenting beyond childhood?  

PubMed

Four cases are reported meeting the criteria of a pediatric (i.e., Type I) testicular germ cell tumor (TGCT), apart from the age of presentation, which is beyond childhood. The tumors encompass the full spectrum of histologies of pediatric TGCT: teratoma, yolk sac tumor, and various combinations of the two, and lack intratubular germ cell neoplasia/carcinoma in situ in the adjacent parenchyma. The neoplasms are (near)diploid, and lack gain of 12p, typical for seminomas and non-seminomas of the testis of adolescents and adults (i.e., Type II). It is proposed that these neoplasms are therefore late appearing pediatric (Type I) TGCT. The present report broadens the concept of earlier reported benign teratomas of the post-pubertal testis to the full spectrum of pediatric TGCT. The possible wide age range of pediatric TGCT, demonstrated in this study, lends credence to the concept that TGCT should according to their pathogenesis be classified into the previously proposed types. This classification is clinically relevant, because Type I mature teratomas are benign tumors, which are candidates for testis conserving surgery, as opposed to Type II mature teratomas, which have to be treated as Type II (malignant) non-seminomas. PMID:25427839

Oosterhuis, J W; Stoop, J A; Rijlaarsdam, M A; Biermann, K; Smit, V T H B M; Hersmus, R; Looijenga, L H J

2015-01-01

129

Molecular genetics of testicular germ cell tumors  

PubMed Central

Testicular germ cell tumors (TGCT) are the most common malignancy in young men. While most TGCT are potentially curable, approximately 5% of patients with TGCT may develop chemoresistance and die from the disease. This review article summarizes current knowledge in genetics underlying the development, progression and chemoresistance of TGCT. Most post-pubertal TGCT originate from intratubular germ cell neoplasia unclassified (IGCNU), which are transformed fetal gonocytes. Development of IGCNU may involve aberrantly activated KITLG/KIT pathway and overexpression of embryonic transcription factors such as NANOG and POU5F1, which leads to suppression of apoptosis, increased proliferation, and accumulation of mutations in gonocytes. Invasive TGCT consistently show gain of chromosome 12p, typically isochromosome 12p. Single gene mutations are uncommon in TGCT. KIT, TP53, KRAS/NRAS, and BRAF are genes most commonly mutated in TGCT and implicated in their pathogenesis. Different histologic subtypes of TGCT possess different gene expression profiles that reflect different directions of differentiation. Their distinct gene expression profiles are likely caused by epigenetic regulation, in particular DNA methylation, but not by gene copy number alterations. Resistance of TGCT to chemotherapy has been linked to karyotypic aberrations, single-gene mutations, and epigenetic regulation of gene expression in small-scale studies. The study of TGCT genetics could ultimately translate into development of new molecular diagnostic and therapeutic modalities for these tumors and improve the care of patients with these malignancies. PMID:22432056

Sheikine, Yuri; Genega, Elizabeth; Melamed, Jonathan; Lee, Peng; Reuter, Victor E.; Ye, Huihui

2012-01-01

130

Alvocidib and Oxaliplatin With or Without Fluorouracil and Leucovorin Calcium in Treating Patients With Relapsed or Refractory Germ Cell Tumors  

ClinicalTrials.gov

Recurrent Extragonadal Seminoma; Recurrent Malignant Extragonadal Germ Cell Tumor; Recurrent Malignant Extragonadal Non-Seminomatous Germ Cell Tumor; Recurrent Malignant Testicular Germ Cell Tumor; Recurrent Ovarian Germ Cell Tumor; Stage III Testicular Cancer; Stage IV Extragonadal Non-Seminomatous Germ Cell Tumor; Stage IV Extragonadal Seminoma; Stage IV Ovarian Germ Cell Tumor

2015-03-12

131

Dynamic regulation of mitochondrial genome maintenance in germ cells.  

PubMed

Mitochondria play a crucial role in the development and function of germ cells. Mitochondria contain a maternally inherited genome that should be transmitted to offspring without reactive oxygen species-induced damage during germ line development. Germ cells are also involved in the mitochondrial DNA (mtDNA) bottleneck; thus, the appropriate regulation of mtDNA in these cells is very important for this characteristic transmission. In this review, we focused on unique regulation of the mitochondrial genome in animal germ cells; paternal elimination and the mtDNA bottleneck in females. We also summarized the mitochondrial nucleoid factors involved in various mtDNA regulation pathways. Among them, mitochondrial transcription factor A (TFAM), which has pleiotropic and essential roles in mtDNA maintenance, appears to have putative roles in germ cell regulation. PMID:24482608

Kasashima, Katsumi; Nagao, Yasumitsu; Endo, Hitoshi

2014-01-01

132

Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to static vs. dynamic light exposure in upper mixed-layer summer sea waters  

NASA Astrophysics Data System (ADS)

Microbial plankton experience short-term fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, fast repetition rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a subtle disruption of the photoinhibition and photoacclimation processes associated with ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions.

Galí, M.; Simó, R.; Pérez, G. L.; Ruiz-González, C.; Sarmento, H.; Royer, S.-J.; Fuentes-Lema, A.; Gasol, J. M.

2013-12-01

133

Differential response of planktonic primary, bacterial, and dimethylsulfide production rates to vertically-moving and static incubations in upper mixed-layer summer sea waters  

NASA Astrophysics Data System (ADS)

Microbial plankton experience fluctuations in total solar irradiance and in its spectral composition as they are vertically moved by turbulence in the oceanic upper mixed layer (UML). The fact that the light exposure is not static but dynamic may have important consequences for biogeochemical processes and ocean-atmosphere fluxes. However, most biogeochemical processes other than primary production, like bacterial production or dimethylsulfide (DMS) production, are seldom measured in sunlight and even less often in dynamic light fields. We conducted four experiments in oligotrophic summer stratified Mediterranean waters, where a sample from the UML was incubated in ultraviolet (UV)-transparent bottles at three fixed depths within the UML and on a vertically-moving basket across the same depth range. We assessed the response of the phyto- and bacterioplankton community with physiological indicators based on flow cytometry singe-cell measurements, Fast Repetition Rate fluorometry (FRRf), phytoplankton pigment concentrations and particulate light absorption. Dynamic light exposure caused a disruption of the photoinhibition and photoacclimation processes associated to ultraviolet radiation (UVR), which slightly alleviated bacterial photoinhibition but did not favor primary production. Gross DMS production (GPDMS) decreased sharply with depth in parallel to shortwave UVR, and displayed a dose-dependent response that mixing did not significantly disrupt. To our knowledge, we provide the first measurements of GPDMS under in situ UV-inclusive optical conditions.

Galí, M.; Simó, R.; Pérez, G. L.; Ruiz-González, C.; Sarmento, H.; Royer, S.-J.; Fuentes-Lema, A.; Gasol, J. M.

2013-05-01

134

Differential alterations in the morphology and electrophysiology of layer II pyramidal cells in the primary visual cortex of a mouse model prenatally exposed to LPS.  

PubMed

Maternal inflammation is a known risk factor for schizophrenia and autism. Since the visual processing has shown abnormalities in these disorders, we explored whether neuropathologic changes can be caused in the primary visual cortex in offsprings due to the maternal inflammation induced by a single lipopolysaccharide (LPS) injection in pregnant mouse dams. The morphology and electrophysiological properties of layer II pyramidal cells (L2PC) in the primary visual cortex were investigated with whole-cell patch-clamping recording and 3D neuron reconstruction techniques. Although the composition of two L2PC types was unchanged, a reorganization of the dendritic architecture was found in both L2PC_A and L2PC_B types, predominantly in the L2PC_A type, of the mice prenatally exposed to LPS. Moreover, prenatal LPS exposure differentially altered intrinsic electrophysiological properties of the two L2PC types. L2PC_A neurons showed reduced excitability as featured by a hyperpolarization of the resting membrane potential, whereas L2PC_B neurons showed enhanced excitability as featured by a decrease in cellular input resistance at resting membrane potential. These significant changes in neuronal morphological and electrophysiological properties might contribute to the dysfunctions of pyramidal neurons after maternal inflammation. PMID:25703223

Gao, Ying; Liu, Lixiong; Li, Qiqin; Wang, Yun

2015-03-30

135

Origin and development of the germ line in sea stars.  

PubMed

This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors-vasa, nanos, piwi-and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line into how these animals can help in this research field. The review is not intended to be comprehensive-sea star reproduction has been studied for over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

Wessel, Gary M; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

2014-05-01

136

Protein Interactions in Xenopus Germ Plasm RNP Particles  

PubMed Central

Hermes is an RNA-binding protein that we have previously reported to be found in the ribonucleoprotein (RNP) particles of Xenopus germ plasm, where it is associated with various RNAs, including that encoding the germ line determinant Nanos1. To further define the composition of these RNPs, we performed a screen for Hermes-binding partners using the yeast two-hybrid system. We have identified and validated four proteins that interact with Hermes in germ plasm: two isoforms of Xvelo1 (a homologue of zebrafish Bucky ball) and Rbm24b and Rbm42b, both RNA-binding proteins containing the RRM motif. GFP-Xvelo fusion proteins and their endogenous counterparts, identified with antisera, were found to localize with Hermes in the germ plasm particles of large oocytes and eggs. Only the larger Xvelo isoform was naturally found in the Balbiani body of previtellogenic oocytes. Bimolecular fluorescence complementation (BiFC) experiments confirmed that Hermes and the Xvelo variants interact in germ plasm, as do Rbm24b and 42b. Depletion of the shorter Xvelo variant with antisense oligonucleotides caused a decrease in the size of germ plasm aggregates and loosening of associated mitochondria from these structures. This suggests that the short Xvelo variant, or less likely its RNA, has a role in organizing and maintaining the integrity of germ plasm in Xenopus oocytes. While GFP fusion proteins for Rbm24b and 42b did not localize into germ plasm as specifically as Hermes or Xvelo, BiFC analysis indicated that both interact with Hermes in germ plasm RNPs. They are very stable in the face of RNA depletion, but additive effects of combinations of antisense oligos suggest they may have a role in germ plasm structure and may influence the ability of Hermes protein to effectively enter RNP particles. PMID:24265795

Nijjar, Sarbjit; Woodland, Hugh R.

2013-01-01

137

Origin and development of the germ line in sea stars  

PubMed Central

This review summarizes and integrates our current understanding of how sea stars make gametes. Although little is known of the mechanism of germ line formation in these animals, recent results point to specific cells and to cohorts of molecules in the embryos and larvae that may lay the ground work for future research efforts. A coelomic outpocketing forms in the posterior of the gut in larvae, referred to as the posterior enterocoel (PE), that when removed, significantly reduces the number of germ cell later in larval growth. This same PE structure also selectively accumulates several germ-line associated factors – vasa, nanos, piwi – and excludes factors involved in somatic cell fate. Since its formation is relatively late in development, these germ cells may form by inductive mechanisms. When integrated into the morphological observations of germ cells and gonad development in larvae, juveniles, and adults, the field of germ line determination appears to have a good model system to study inductive germ line determination to complement the recent work on the molecular mechanisms in mice. We hope this review will also guide investigators interested in germ line determination and regulation of the germ line in how these animals can help in this research field. The review is not intended to be comprehensive – sea star reproduction has been studied over 100 years and many reviews are comprehensive in their coverage of, for example, seasonal growth of the gonads in response to light, nutrient, and temperature. Rather the intent of this review is to help the reader focus on new experimental results attached to the historical underpinnings of how the germ cell functions in sea stars with particular emphasis to clarify the important areas of priority for future research. PMID:24648114

Wessel, Gary M.; Fresques, Tara; Kiyomoto, Masato; Yajima, Mamiko; Zazueta, Vanesa

2014-01-01

138

Genetic modification of chicken germ cells  

PubMed Central

Over the past two decades numerous reports have demonstrated that the genetic modification of poultry genomes has great potential for improving poultry production; moreover, it may be used as a powerful tool for the production of industrial proteins. To date, transgenic techniques have been established for generating transgenic birds that express recombinant human proteins in hen eggs, as well as tissue-specific genes as an animal model. The production of transgenic birds is a promising approach that could have practical applications in agriculture and biopharmacology, in addition to advancing our understanding of avian biology. Finally, germ cell–mediated transgenesis could provide a more efficient strategy for creating gene-targeted insertions and deletions in avian species. PMID:23050971

Park, Tae Sub; Han, Jae Yong

2012-01-01

139

The Effect of Wheat Germ Extract on Premenstrual Syndrome Symptoms  

PubMed Central

Pre-menstrual syndrome is one of the most common disorders in women and impairs work and social relationships. Several treatment modalities have been proposed including herbal medicines. Considering the properties of wheat germ, this study aimed to determine the effects of wheat germ extract on the symptoms of premenstrual syndrome. This triple blind clinical trial was conducted on 84 women working in hospitals affiliated to Hamadan University of Medical Sciences. Subjects completed daily symptom record form for two consecutive months. After definitive diagnosis of premenstrual syndrome, they were randomly divided into two groups of 50 people. Then, for two consecutive months, 400 mg capsules of wheat germ extract or placebo were used three times a day, from day 16 until day 5 of the next menstrual cycle. Wheat germ significantly reduced physical symptoms (63.56%), psychological symptoms (66.30%), and the general score (64.99%). Although the severity of symptoms decreased in both groups, this reduction was more significant in the wheat germ extract group (p < 0.001). On the other hand, physical symptoms decreased only in the wheat germ extract (p < 0.001) and there was no statistically significant difference in the placebo group. No complications were observed in any of the groups. It seems that using wheat germ extract reduces general, psychological and physical symptoms. PMID:25561922

Ataollahi, Maryam; Akbari, Sedigheh Amir Ali; Mojab, Faraz; Alavi Majd, Hamid

2015-01-01

140

The making of a germ panic, then and now.  

PubMed Central

Over the last 2 decades, a heightened interest in germs has been evident in many aspects of American popular culture, including news coverage, advertisements, and entertainment media. Although clearly a response to the AIDS epidemic and other recent disease outbreaks, current obsessions with germs have some striking parallels with a similar period of intense anxiety about disease germs that occurred between 1900 and 1940. A comparison of these 2 periods of germ "panic" suggests some of the long-term cultural trends that contributed to their making. Both germ panics reflected anxieties about societal incorporation, associated with expanding markets, transportation networks, and mass immigration. They were also shaped by new trends in public health education, journalism, advertising, and entertainment media. In comparison to the first germ panic, the current discourse about the "revenge of the superbugs" is considerably more pessimistic because of increasing worries about the environment, suspicions of governmental authority, and distrust of expert knowledge. Yet, as popular anxieties about infectious disease have increased, public health scientists have been attracting favorable coverage in their role as "medical detectives" on the trail of the "killer germ." PMID:10667179

Tomes, N

2000-01-01

141

Hedgehog does not guide migrating Drosophila germ cells.  

PubMed

In many species, the germ cells, precursors of sperm and egg, migrate during embryogenesis. The signals that regulate this migration are thus essential for fertility. In flies, lipid signals have been shown to affect germ cell guidance. In particular, the synthesis of geranylgeranyl pyrophosphate through the 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (Hmgcr) pathway is critical for attracting germ cells to their target tissue. In a genetic analysis of signaling pathways known to affect cell migration of other migratory cells, we failed to find a role for the Hedgehog (Hh) pathway in germ cell migration. However, previous reports had implicated Hh as a germ cell attractant in flies and suggested that Hh signaling is enhanced through the action of the Hmgcr pathway. We therefore repeated several critical experiments and carried out further experiments to test specifically whether Hh is a germ cell attractant in flies. In contrast to previously reported findings and consistent with findings in zebrafish our data do not support the notion that Hh has a direct role in the guidance of migrating germ cells in flies. PMID:19389345

Renault, Andrew D; Ricardo, Sara; Kunwar, Prabhat S; Santos, Ana; Starz-Gaiano, Michelle; Stein, Jennifer A; Lehmann, Ruth

2009-04-15

142

Hedgehog does not guide migrating Drosophila germ cells  

PubMed Central

In many species, the germ cells, precursors of sperm and egg, migrate during embryogenesis. The signals that regulate this migration are thus essential for fertility. In flies, lipid signals have been shown to affect germ cell guidance. In particular, the synthesis of geranylgeranyl pyrophosphate through the 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (Hmgcr) pathway is critical for attracting germ cells to their target tissue. In a genetic analysis of signaling pathways known to affect cell migration of other migratory cells, we failed to find a role for the Hedgehog (Hh) pathway in germ cell migration. However, previous reports had implicated Hh as a germ cell attractant in flies and suggested that Hh signaling is enhanced through the action of the Hmgcr pathway. We therefore repeated several critical experiments and carried out further experiments to test specifically whether Hh is a germ cell attractant in flies. In contrast to previously reported findings and consistent with findings in zebrafish our data do not support the notion that Hh has a direct role in the guidance of migrating germ cells in flies. PMID:19389345

Renault, Andrew D.; Ricardo, Sara; Kunwar, Prabhat S.; Santos, Ana; Starz-Gaiano, Michelle; Stein, Jennifer; Lehmann, Ruth

2009-01-01

143

Germ-line and somatic DICER1 mutations in pineoblastoma  

PubMed Central

Germ-line RB-1 mutations predispose to pineoblastoma (PinB), but other predisposing genetic factors are not well established. We recently identifed a germ-line DICER1 mutation in a child with a PinB. This was accompanied by loss of heterozygosity (LOH) of the wild-type allele within the tumour. We set out to establish the prevalence of DICER1 mutations in an opportunistically ascertained series of PinBs. Twenty-one PinB cases were studied: eighteen cases had not undergone previous testing for DICER1 mutations; three patients were known carriers of germ-line DICER1 mutations. The eighteen PinBs were sequenced by Sanger and/or Fluidigm-based next-generation sequencing to identify DICER1 mutations in blood gDNA and/or tumour gDNA. Testing for somatic DICER1 mutations was also conducted on one case with a known germ-line DICER1 mutation. From the eighteen PinBs, we identified four deleterious DICER1 mutations, three of which were germ line in origin, and one for which a germ line versus somatic origin could not be determined; in all four, the second allele was also inactivated leading to complete loss of DICER1 protein. No somatic DICER1 RNase IIIb mutations were identified. One PinB arising in a germ-line DICER1 mutation carrier was found to have LOH. This study suggests that germ-line DICER1 mutations make a clinically significant contribution to PinB, establishing DICER1 as an important susceptibility gene for PinB and demonstrates PinB to be a manifestation of a germ-line DICER1 mutation. The means by which the second allele is inactivated may differ from other DICER1-related tumours. PMID:25022261

de Kock, Leanne; Sabbaghian, Nelly; Druker, Harriet; Weber, Evan; Hamel, Nancy; Miller, Suzanne; Choong, Catherine S.; Gottardo, Nicholas G.; Kees, Ursula R.; Rednam, Surya P.; van Hest, Liselotte P.; Jongmans, Marjolijn C.; Jhangiani, Shalini; Lupski, James R.; Zacharin, Margaret; Bouron-Dal Soglio, Dorothée; Huang, Annie; Priest, John R.; Perry, Arie; Mueller, Sabine; Albrecht, Steffen; Malkin, David; Grundy, Richard G.

2015-01-01

144

Intracranial germ-cell tumors: natural history and pathogenesis.  

PubMed

The natural history of primary intracranial germ-cell tumors (GCT's) is defined from 389 previously published cases, of which 65% were germinomas, 18% teratomas, 5% embryonal carcinomas, 7% endodermal sinus tumors, and 5% choriocarcinomas. Intracranial GCT's display specificity in site of origin. Ninety-five percent arise along the midline from the suprasellar cistern (37%) to the pineal gland (48%), and an additional 6% involve both sites. The majority of germinomas (57%) arise in the suprasellar cistern, while most nongerminomatous GCT's (68%) preferentially involve the pineal gland (p less than 0.0001). The age distribution of afflicted patients is unimodal, centering with an abrupt surge in frequency in the early pubertal years; 68% of patients are diagnosed between 10 and 21 years of age. Nongerminomatous GCT's demonstrate an earlier age of onset than do germinomas (p less than 0.0001). Prolonged symptomatic intervals prior to diagnosis are common in germinomas (p = 0.0007), in suprasellar GCT's (p = 0.001), and among females (p = 0.02). Parasellar germinomas commonly present with diabetes insipidus, visual field defects, and hypothalamic-pituitary failure. Nongerminomatous GCT's present as posterior third ventricular masses with hydrocephalus and midbrain compression. Germ-cell tumors may infiltrate the hypothalamus (11%), or disseminate to involve the third ventricle (22%) and spinal cord (10%). Among a subpopulation of 263 conventionally treated patients, two factors were of prognostic significance: 1) histological diagnosis; germinomas were associated with significantly longer survival than nongerminomatous GCT's (p less than 0.0001); and 2) staging of the extent of disease; this emphasizes the ominous character of involvement of the hypothalamus (p = 0.0002), third ventricle (p = 0.02), or spinal cord (p = 0.01). Specific recommendations regarding the necessity of histological diagnosis and staging of the extent of disease are made in light of modern chemotherapeutic advances. The pathogenesis of GCT's may be revealed by their specificity of origin within the positive (suprasellar cistern-suprachiasmatic nucleus) and negative (pineal) regulatory centers for gonadotropin secretion within the diencephalon. The abrupt rise in age distribution at 10 to 12 years suggests that the neuroendocrine events of puberty are an "activating" influence in the malignant expression of these embryonal tumors. PMID:2991485

Jennings, M T; Gelman, R; Hochberg, F

1985-08-01

145

Lipase inactivation in wheat germ by gamma irradiation  

NASA Astrophysics Data System (ADS)

An attempt was made to improve the shelf life of wheat germ by optimizing processing conditions involving ?-irradiation. Studies were carried out to investigate the effect of ?-irradiation (0-30 kGy doses) on the chemical composition of wheat germ with respect to variation in moisture, total ash, crude fat, free fatty acid, protein and lipase activity. The results demonstrate that shelf stability of wheat germ was achieved by inactivation of lipase at doses of ?-irradiation greater than 12 kGy.

Jha, Pankaj Kumar; Kudachikar, V. B.; Kumar, Sourav

2013-05-01

146

Expression of the c-Kit receptor in germ cells of the seminiferous epithelium in rats with hormonal imbalance.  

PubMed

The aim of the study was to investigate the effects of pharmacologically induced hormonal imbalance in adult male rats treated with letrozole and rats exposed to soya isoflavones on the testicular morphology and c-Kit receptor (c-Kit-R) expression in germ cells. The study was conducted during all developmental periods: prenatal period, lactation, youth, and sexual maturity. Morphological and morphometrical analyses were performed on testicular section, and c-Kit-R was identified using immunohistochemistry. In addition, concentration of circulating steroids was measured in mature rats exposed to soya isoflavones. A significant reduction in testosterone level in rats exposed to soya isoflavones, and the sloughing of the premature germ cells into the lumen of the seminiferous tubules in the testes of both groups of rats were observed. Immunohistochemistry showed a decrease in c-Kit-R expression in germ cells of both experimental groups. Morphometric analysis indicated a decreased thickness of the layers occupied by c-Kit-R-positive spermatogonia, and a decreased diameter of the seminiferous tubules in the testes of both experimental groups of animals. In conclusion, the pharmacologically induced reduction of the estradiol level in adult rats and the diminished level of testosterone in rats exposed to soya isoflavones during the prenatal period, lactation and up to maturity caused similar morphological and functional changes associated with the decreased c-Kit-R expression in germ cells in the seminiferous epithelium. These findings demonstrate the importance of the estrogen/androgen balance for normal testicular morphology and spermatogenesis. PMID:24287042

Misiakiewicz, Kamila; Kolasa, Agnieszka; Kondarewicz, Anna; Marchlewicz, Mariola; Wiszniewska, Barbara

2013-12-01

147

A Specialized Outer Layer of the Primary Cell Wall Joins Elongating Cotton Fibers into Tissue-Like Bundles1[W][OA  

PubMed Central

Cotton (Gossypium hirsutum) provides the world's dominant renewable textile fiber, and cotton fiber is valued as a research model because of its extensive elongation and secondary wall thickening. Previously, it was assumed that fibers elongated as individual cells. In contrast, observation by cryo-field emission-scanning electron microscopy of cotton fibers developing in situ within the boll demonstrated that fibers elongate within tissue-like bundles. These bundles were entrained by twisting fiber tips and consolidated by adhesion of a cotton fiber middle lamella (CFML). The fiber bundles consolidated via the CFML ultimately formed a packet of fiber around each seed, which helps explain how thousands of cotton fibers achieve their great length within a confined space. The cell wall nature of the CFML was characterized using transmission electron microscopy, including polymer epitope labeling. Toward the end of elongation, up-regulation occurred in gene expression and enzyme activities related to cell wall hydrolysis, and targeted breakdown of the CFML restored fiber individuality. At the same time, losses occurred in certain cell wall polymer epitopes (as revealed by comprehensive microarray polymer profiling) and sugars within noncellulosic matrix components (as revealed by gas chromatography-mass spectrometry analysis of derivatized neutral and acidic glycosyl residues). Broadly, these data show that adhesion modulated by an outer layer of the primary wall can coordinate the extensive growth of a large group of cells and illustrate dynamic changes in primary wall structure and composition occurring during the differentiation of one cell type that spends only part of its life as a tissue. PMID:19369592

Singh, Bir; Avci, Utku; Eichler Inwood, Sarah E.; Grimson, Mark J.; Landgraf, Jeff; Mohnen, Debra; Sørensen, Iben; Wilkerson, Curtis G.; Willats, William G.T.; Haigler, Candace H.

2009-01-01

148

Ki-A10, a Germ Cell Nuclear Antigen Retained in a Subset of Germ Cell-Derived Tumors  

PubMed Central

Monoclonal antibody Ki-A10 recognizes a nuclear antigen of 25 and 22 kd apparent molecular mass, which is abundantly expressed by immature gonocytes, spermatogonia, and spermatocytes, whereas it is absent in spermatids, spermatozoa, oocytes, and normal somatic tissues. In a broad spectrum of human cancers the antibody showed no reactivity except for a small subset of malignant lymphomas. Because of this restricted expression pattern, we examined 173 germ cell tumors and 18 sex cord stromal tumors immunohistochemically to assess the distribution of the Ki-A10 antigen. A strongly positive reaction was found in classic seminomas, dysgerminomas, spermatocytic seminomas, and the germ cell component of gonadoblastomas. Yolk sac tumors presented a heterogeneous reactivity pattern ranging from overall positivity to complete lack of antigen expression, and in three of eight choriocarcinomas, a few clusters of cytotrophoblast cells were strongly labeled. All other tumors, including Leydig and Sertoli cell tumors as well as placental tissue, were negative. Our findings suggest that specific germ cell antigens can be retained in germ cell tumors along particular differentiation pathways. Ki-A10 is the first marker that consistently labels spermatocytic seminoma, further confirming its germ cell origin and suggesting a close relationship to classic seminoma. The antibody may serve for diagnostic purposes and promises new insights into the process of germ cell differentiation and the development of germ cell-derived neoplasia. PMID:10079257

Rudolph, Pierre; Kellner, Udo; Schmidt, Dietmar; Kirchner, Vera; Talerman, Aleksander; Harms, Dieter; Parwaresch, Reza

1999-01-01

149

SALL4 EXPRESSION IN GERM CELL AND NON GERM-CELL TUMORS – A SYSTEMATIC IMMUNOHISTOCHEMICAL STUDY OF 3215 CASES  

PubMed Central

SALL4 transcription factor is associated with embryonic cell pluripotency and has been shown as a useful immunohistochemical marker for germ cell tumors. However, information of SALL4 distribution in normal human tissues and non germ-cell tumors is limited. In this study we examined normal human tissues and 3215 tumors for SALL4 expression using a monoclonal antibody 6E3 and automated immunohistochemistry. In a 10th week embryo, SALL4 was expressed in ovocytes, intestine, kidney, and some hepatocytes. In adult tissues, it was only detected in germ cells. SALL4 was consistently expressed in all germ cell tumors except some trophoblastic tumors and mature components of teratomas, where it was selectively expressed in intestinal-like and some squamous epithelia. In non germ-cell carcinomas, SALL4 was detected in 20% of cases or more of serous carcinoma of ovary, urothelial high-grade carcinoma, and gastric adenocarcinoma (especially the intestinal type). SALL4 was only rarely (?5%) expressed in mammary, colorectal, prostatic, and squamous cell carcinomas. Many SALL4 positive carcinomas showed poorly differentiated patterns and some showed positivity in most tumor cells mimicking the expression in germ cell tumors. SALL4 was commonly expressed in rhabdoid tumors of kidney and extrarenal sites, and in Wilms tumor. Expression of SALL4 was rare in other mesenchymal and neuroendocrine tumors but was occasionally detected in melanoma, desmoplastic small round cell tumor, epithelioid sarcoma, and rhabdomyosarcoma. All hematopoietic tumors were negative. SALL4 is an excellent marker of non-teratomatous germ cell tumors, but it is also expressed in other tumors, sometimes extensively. Such expression may reflect stem-cell like differentiation and must be considered when using SALL4 as a marker for germ cell tumors. Observed lack of other pluripotency factors, OCT4 and NANOG, in SALL4-positive non-germ cell tumors can also be diagnostically helpful. PMID:24525512

Miettinen, Markku; Wang, Zengfeng; Mc. Cue, Peter A.; Sarlomo-Rikala, Maarit; Rys, Janusz; Biernat, Wojciech; Lasota, Jerzy; Lee, Yi-Shan

2014-01-01

150

Lipid phosphate phosphatase activity regulates dispersal and bilateral sorting of embryonic germ cells in Drosophila  

PubMed Central

In Drosophila, germ cell survival and directionality of migration are controlled by two lipid phosphate phosphatases (LPP), wunen (wun) and wunen-2 (wun2). wun wun2 double mutant analysis reveals that the two genes, hereafter collectively called wunens, act redundantly in primordial germ cells. We find that wunens mediate germ cell-germ cell repulsion and that this repulsion is necessary for germ cell dispersal and proper transepithelial migration at the onset of migration and for the equal sorting of the germ cells between the two embryonic gonads during their migration. We propose that this dispersal function optimizes adult fecundity by assuring maximal germ cell occupancy of both gonads. Furthermore, we find that the requirement for wunens in germ cell survival can be eliminated by blocking germ cell migration. We suggest that this essential function of Wunen is needed to maintain cell integrity in actively migrating germ cells. PMID:20431117

Renault, Andrew D.; Kunwar, Prabhat S.; Lehmann, Ruth

2010-01-01

151

American Society of Clinical Oncology Clinical Practice Guideline on Uses of Serum Tumor Markers in Adult Males With Germ Cell Tumors  

Microsoft Academic Search

Purpose To provide recommendations on appropriate uses for serum markers of germ cell tumors (GCTs). Methods Searches of MEDLINE and EMBASE identified relevant studies published in English. Primary outcomes included marker accuracy to predict the impact of marker-based decisions on out- comes. Secondary outcomes included proportions with elevated markers and statistical tests of elevations as prognostic factors. An expert panel

Timothy D. Gilligan; Jerome Seidenfeld; Ethan M. Basch; Lawrence H. Einhorn; Timothy Fancher; David C. Smith; Andrew J. Stephenson; David J. Vaughn; Roxanne Cosby; Daniel F. Hayes

2010-01-01

152

Cryopreservation of human testicular diploid germ cell suspensions.  

PubMed

For patients with threatened fertility, preservation of it is a major concern. Although promising results have been obtained in animal models using testicular germ cell suspensions, in humans, it is crucial to first develop an efficient method of cryopreservation to be able to apply to transplantation. Thus, four reliable and available cryopreservation techniques in any fertility centre were tested to cryopreserve an enriched fraction of diploid germ cells isolated from human testicular biopsies. The protocols were evaluated based on cell viability, and the results showed significant differences between the four methods. The semen and tissue cryopreservation methods appeared to be inadequate for diploid germ cell suspensions, and programmed slow freezing gave significantly lower results than open pulled straw vitrification; the latter was found to be the protocol that best preserved cell viability. The vitrification of isolated human diploid germ cells is innovative and constitutes valuable information for cryopreservation in cases of transplants or in vitro maturation. PMID:22420610

Sá, R; Cremades, N; Malheiro, I; Sousa, M

2012-12-01

153

Developmental transitions of germ cell lineage of the mouse  

E-print Network

Mammalian germ cells arise during early embryogenesis and migrate to the developing gonad where, under the direction of the somatic environment, they initiate distinct sex-specific developmental programs resulting in the ...

Baltus, Andrew Edmund

2006-01-01

154

Retroperitoneal Extragonadal Nonseminomatous Germ Cell Tumor with Synchronous Orbital Metastasis  

PubMed Central

A huge retroperitoneal tumor with a right orbital mass was detected and proved to be an extragonadal nonseminomatous germ cell tumor on biopsy. BEP chemotherapy caused some regression in orbital mass however no change in retroperitoneal tumor size as well as serum tumor marker levels occurred. Herein, we present a rarely seen entity of extragonadal retroperitoneal nonseminomatous germ cell tumor with synchronous orbital metastases and discuss its diagnosis and management. PMID:19197374

Atmaca, Ali Fuat; Alt?nova, Serkan; Canda, Abdullah Erdem; Ozcan, M. Fuat; Al?c?, Suleyman; Mem?s, Leyla; Balbay, M. Derya

2009-01-01

155

Increased apoptosis of germ cells in patients with AZFc deletions  

Microsoft Academic Search

Purpose  AZFc deletions are associated with variable testicular histology ranging from the Sertoli cell only to spermatogenic arrest\\u000a and hypospermatogenesis. Such variable phenotypes may be explained by progressive germ cell regression over time. Increased\\u000a apoptosis is likely responsible for progressive regression of spermatogenic potential. This study evaluated germ cell apoptosis\\u000a as a cause of the progressive decrease in the number of

Kyoko Yamada; Kazuyuki Fujita; Jinhua Quan; Masayuki Sekine; Katsunori Kashima; Tetsuro Yahata; Kenichi Tanaka

2010-01-01

156

Tritium effects on germ cells and fertility  

SciTech Connect

Primordial oocytes in juvenile mice show acute gamma-ray LD/sub 50/ as low as 6 rad. This provides opportunities for determining dose-response relations at low doses and chronic exposure in the intact animal - conditions of particular interest for hazard evaluation. Examined in this way, /sup 3/HOH in body water is found to kill murine oocytes exponentially with dose, the LD/sub 50/ level for chronic exposure being only 2..mu..Ci/ml (delivering 0.4 rad/day). At very low doses and dose rates, where comparisons between tritium and other radiations are of special significance for radiological protection, the RBE of tritium compared with /sup 60/Co gamma radiation reaches approximately 3. Effects on murine fertility from tritium-induced oocyte loss have been quantified by reproductive capacity measurements. Chronic low-level exposure has been examined also in three primate species - squirrel, rhesus, and bonnet monkeys. In squirrel monkeys the ovarian germ-cell supply is 99% destroyed by the time of birth from prenatal exposure to body-water levels of /sup 3/HOH (administered in maternal drinking water) of only 3 ..mu..Ci/ml, the LD/sub 50/ level being 0.5 ..mu..Ci/ml (giving 0.1 rad/day), one fourth that in mice. Though not completely ruled out, similar high sensitivity of female germ cells has not been found in macaques; and it probably does not occur in man. The exquisite radiosensitivity of primordial oocytes in mice is apparently due to vulnerability of the plasma membrane (or something of similar geometry and location), not DNA. Evidence for this comes from tritium data as well as neutron studies. Tritium administered as /sup 3/HOH, and therefore generally distributed, is much more effective in killing murine oocytes than is tritium administered as /sup 3/H-TdR, localized in the nucleus. This situation in the mouse may have implications for estimating radiation genetic risk in the human female.

Dobson, R.L.; Kwan, T.C.; Straume, T.

1982-11-19

157

Germ cell development in the human and marmoset fetal testis and the origins of testicular germ cell tumours   

E-print Network

Normal germ cell development in the human testis is crucial for subsequent fertility and reproductive health. Disruption of testis development in fetal life can result in deleterious health consequences such as testicular dysgenesis syndrome (TDS...

Mitchell, Roderick T.

2010-01-01

158

Expression of BLIMP1\\/PRMT5 and concurrent histone H2A\\/H4 arginine 3 dimethylation in fetal germ cells, CIS\\/IGCNU and germ cell tumors  

Microsoft Academic Search

BACKGROUND: Most testicular germ cell tumors arise from intratubular germ cell neoplasia unclassified (IGCNU, also referred to as carcinoma in situ), which is thought to originate from a transformed primordial germ cell (PGC)\\/gonocyte, the fetal germ cell. Analyses of the molecular profile of IGCNU and seminoma show similarities to the expression profile of fetal germ cells\\/gonocytes. In murine PGCs, expression

Dawid Eckert; Katharina Biermann; Daniel Nettersheim; Ad JM Gillis; Klaus Steger; Hans-Martin Jäck; Annette M Müller; Leendert HJ Looijenga; Hubert Schorle

2008-01-01

159

A Mechanism of Male Germ Cell Apoptosis Induced by Bisphenol-A and Nonylphenol Involving ADAM17 and p38 MAPK Activation  

PubMed Central

Germ cell apoptosis regulation is pivotal in order to maintain proper daily sperm production. Several reports have shown that endocrine disruptors such as Bisphenol-A (BPA) and Nonylphenol (NP) induce germ cell apoptosis along with a decrease in sperm production. Given their ubiquitous distribution in plastic products used by humans it is important to clarify their mechanism of action. TACE/ADAM17 is a widely distributed extracellular metalloprotease and participates in the physiological apoptosis of germ cells during spermatogenesis. The aims of this work were: 1) to determine whether BPA and NP induce ADAM17 activation; and 2) to study whether ADAM17 and/or ADAM10 are involved in germ cell apoptosis induced by BPA and NP in the pubertal rat testis. A single dose of BPA or NP (50 mg/kg) induces germ cell apoptosis in 21-day-old male rats, which was prevented by a pharmacological inhibitor of ADAM17, but not by an inhibitor of ADAM10. In vitro, we showed that BPA and NP, at similar concentrations to those found in human samples, induce the shedding of exogenous and endogenous (TNF-?) ADAM17 substrates in primary rat Sertoli cell cultures and TM4 cell line. In addition, pharmacological inhibitors of metalloproteases and genetic silencing of ADAM17 prevent the shedding induced in vitro by BPA and NP. Finally, we showed that in vivo BPA and NP induced early activation (phosphorylation) of p38 MAPK and translocation of ADAM17 to the cell surface. Interestingly, the inhibition of p38 MAPK prevents germ cell apoptosis and translocation of ADAM17 to the cell surface. These results show for the first time that xenoestrogens can induce activation of ADAM17 at concentrations similar to those found in human samples, suggesting a mechanism by which they could imbalance para/juxtacrine cell-to-cell-communication and induce germ cell apoptosis. PMID:25474107

Moreno, Ricardo D.

2014-01-01

160

Maternally localized germ plasm mRNAs and germ cell/stem cell formation in the cnidarian Clytia.  

PubMed

The separation of the germ line from the soma is a classic concept in animal biology, and depending on species is thought to involve fate determination either by maternally localized germ plasm ("preformation" or "maternal inheritance") or by inductive signaling (classically termed "epigenesis" or "zygotic induction"). The latter mechanism is generally considered to operate in non-bilaterian organisms such as cnidarians and sponges, in which germ cell fate is determined at adult stages from multipotent stem cells. We have found in the hydrozoan cnidarian Clytia hemisphaerica that the multipotent "interstitial" cells (i-cells) in larvae and adult medusae, from which germ cells derive, express a set of conserved germ cell markers: Vasa, Nanos1, Piwi and PL10. In situ hybridization analyses unexpectedly revealed maternal mRNAs for all these genes highly concentrated in a germ plasm-like region at the egg animal pole and inherited by the i-cell lineage, strongly suggesting i-cell fate determination by inheritance of animal-localized factors. On the other hand, experimental tests showed that i-cells can form by epigenetic mechanisms in Clytia, since larvae derived from both animal and vegetal blastomeres separated during cleavage stages developed equivalent i-cell populations. Thus Clytia embryos appear to have maternal germ plasm inherited by i-cells but also the potential to form these cells by zygotic induction. Reassessment of available data indicates that maternally localized germ plasm molecular components were plausibly present in the common cnidarian/bilaterian ancestor, but that their role may not have been strictly deterministic. PMID:22309706

Leclère, Lucas; Jager, Muriel; Barreau, Carine; Chang, Patrick; Le Guyader, Hervé; Manuel, Michaël; Houliston, Evelyn

2012-04-15

161

Intratubular germ cell neoplasia of the testis: a brief review.  

PubMed

Germ cell tumors of the testis may be divided into 3 broad categories according to age at presentation. The tumors in the pediatric age group include teratoma and yolk sac tumor. These tumors are generally not associated with convincing intratubular neoplasia. The second group consists of tumors presenting in third and fourth decade of life and include seminoma, embryonal carcinoma, yolk sac tumor, choriocarcinoma, and teratoma as well as mixed germ cell tumors. The precursor cell for these tumors is an abnormal gonocyte that fails to differentiate completely into spermatogonia. These abnormal cells stay dormant in the gonad during intrauterine life as well as infancy and childhood, but undergo proliferation during puberty and can be identified as intratubular germ cell neoplasia unclassified (IGCNU). These tumor cells continue to manifest protein expression pattern that resembles primitive germ cells (PLAP, c-KIT, OCT3/4). After a variable interval following puberty, IGCNU cells may acquire ability to penetrate the seminiferous tubules and present as an overt germ cell tumor. Acquisition of isochrome 12 and other genetic abnormalities are usually associated with this transition. The level of DNA methylation generally determines the phenotype of the germ cell tumor. The third type of germ cell tumors is spermatocytic seminoma, which is a rare tumor encountered later in life usually in fifth and sixth decade. The cell of origin of this tumor is probably postpubertal mature spermatogonia which acquire abnormal proliferative capability probably due to gain of chromosome 9 resulting in activation and amplification of genes such as DMRT1. The tumor cells manifest many of the proteins normally expressed by mature sperms such as VASA, SSX2, and occasionally OCT2. Although spermatocytic seminoma may also have an intratubular growth phase, it completely lacks features of IGCNU. PMID:25844678

Al-Hussain, Turki; Bakshi, Nasir; Akhtar, Mohammed

2015-05-01

162

Folding and homodimerization of wheat germ agglutinin.  

PubMed

Wheat germ agglutinin (WGA) is emblematic of proteins that specialize in the recognition of carbohydrates. It was the first lectin reported to have a capacity for discriminating between normal and malignant cells. Since then, it has become a preferred model for basic research and is frequently considered in the development of biomedical and biotechnological applications. However, the molecular basis for the structural stability of this homodimeric lectin remains largely unknown, a situation that limits the rational manipulation and modification of its function. In this work we performed a thermodynamic characterization of WGA folding and self-association processes as a function of pH and temperature by using differential scanning and isothermal dilution calorimetry. WGA is monomeric at pH 2, and one of its four hevein-like domains is unfolded at room temperature. Under such conditions, the agglutinin exhibits a fully reversible thermal unfolding that consists of three two-state transitions. At higher pH values, the protein forms weak, nonobligate dimers. This behavior contrasts with that observed for the other plant lectins studied thus far, which form strong, obligate oligomers, indicating a distinctly different molecular basis for WGA function. For dimer formation, the four domains must be properly folded. Nevertheless, depending on the solution conditions, self-association may be coupled with folding of the labile domain. Therefore, dimerization may proceed as a rigid-body-like association or a folding-by-binding event. This hybrid behavior is not seen in other plant lectins. The emerging molecular picture for the WGA assembly highlights the need for a reexamination of existing ligand-binding data in the literature. PMID:21943423

Portillo-Téllez, María Del Carmen; Bello, Martiniano; Salcedo, Guillermo; Gutiérrez, Gabriel; Gómez-Vidales, Virginia; García-Hernández, Enrique

2011-09-21

163

The chemosensitivity of testicular germ cell tumors.  

PubMed

Although rare cancers overall, testicular germ cell tumors (TGCTs) are the most common type of cancer in young males below 40 years of age. Both subtypes of TGCTs, i.e., seminomas and non-seminomas, are highly curable and the majority of even metastatic patients may expect to be cured. These high cure rates are not due to the indolent nature of these cancers, but rather to their sensitivity to chemotherapy (and for seminomas to radiotherapy). The delineation of the cause of chemosensitivity at the molecular level is of paramount importance, because it may provide insights into the minority of TGCTs that are chemo-resistant and, thereby, provide opportunities for specific therapeutic interventions aimed at reverting them to chemosensitivity. In addition, delineation of the molecular basis of TGCT chemo-sensitivity may be informative for the cause of chemo-resistance of other more common types of cancer and, thus, may create new therapeutic leads. p53, a frequently mutated tumor suppressor in cancers in general, is not mutated in TGCTs, a fact that has implications for their chemo-sensitivity. Oct4, an embryonic transcription factor, is uniformly expressed in the seminoma and embryonic carcinoma components of non-seminomas, and its interplay with p53 may be important in the chemotherapy response of these tumors. This interplay, together with other features of TGCTs such as the gain of genetic material from the short arm of chromosome 12 and the association with disorders of testicular development, will be discussed in this paper and integrated in a unifying hypothesis that may explain their chemo-sensitivity. PMID:24692098

Voutsadakis, Ioannis A

2014-04-01

164

Transgenic zebrafish with fluorescent germ cell: a useful tool to visualize germ cell proliferation and juvenile hermaphroditism in vivo.  

PubMed

Juvenile zebrafish are hermaphroditic; undifferentiated gonads first develop into ovary-like tissues, which then either become ovaries and produce oocytes (female) or degenerate and develop into testes (male). In order to fully capture the dynamic processes of germ cells' proliferation and juvenile hermaphroditism in zebrafish, we established transgenic lines TG(beta-actin:EGFP), harboring an enhanced green fluorescent protein (EGFP) gene driven by a medaka beta-actin promoter. In TG(beta-actin:EGFP), proliferating germ cells and female gonads strongly expressed EGFP, but fluorescence was only dimly detected in male gonads. Based on the fluorescent (+) or nonfluorescent (-) appearance of germ cells seen in living animals, three distinct groups were evident among TG(beta-actin:EGFP). Transgenics in ++ group (44%) were females, had fluorescent germ cells as juveniles, and female gonads continuously fluoresced throughout sexual maturation. Transgenics in +- (23%) and -- (33%) groups were males. Fluorescent germ cells were transiently detected in +- transgenics from 14 to 34 days postfertilization (dpf), but were not detected in -- transgenics throughout their life span. Histological analyses showed that 26-dpf-old transgenics in ++, +-, and -- groups all developed ovary-like tissues: Germ cells in -- group juveniles arrested at the gonocyte stage and accumulated low quantities of EGFP, while those in ++ group juveniles highly proliferated into diplotene to perinucleolar stages and accumulated high quantities of EGFP. In +- group juveniles, degenerating oocytes, gonocytes, and spermatogonia were coexistent in transiently fluorescent gonads. Therefore, the fluorescent appearance of gonads in this study was synchronous with the differentiation of ovary-like tissues. Thus, TG(beta-actin:EGFP) can be used to visualize germ cells' proliferation and juvenile hermaphroditism in living zebrafish for the first time. PMID:14550794

Hsiao, Chung-Der; Tsai, Huai-Jen

2003-10-15

165

Metastatic cancer with unknown primary.  

PubMed

Close cooperation between an experienced pathologist and oncologist is essential in the management of patients with unknown primary carcinoma. A comprehensive pathological examination is crucial and, with undifferentiated tumors, this will include immunohistology and/or electron microscopy. Ample properly processed tissue therefore must be provided. Time-consuming and costly radiographic and imaging studies should be avoided. No matter how extensive the evaluation, in a majority of cases, the primary site will never be found, so a selective search for treatable tumors is most appropriate and cost-effective. With adenocarcinomas, this will include prostate, breast, and ovary; for undifferentiated tumors, small cell bronchogenic carcinoma, lymphomas, and germ cell tumors. Table 4 summarizes recommended studies for diagnosing unknown primary undifferentiated or adenocarcinomas. Women with adenocarcinoma in axillary nodes without a primary site should be treated as having breast cancer. Estrogen and progesterone receptor assays are to be obtained on the axillary biopsy. High and midcervical nodes with metastatic squamous cell carcinoma can be treated effectively and, not infrequently, cured with surgery and radiation therapy, even if the primary site never is detected. If doubt remains, treatment should be selected that offers the best chance of significant palliation or cure--for example, cisplatin-based chemotherapy in possible extragonadal germ cell tumors. PMID:2842554

Greenberg, B R; Lawrence, H J

1988-09-01

166

Cross-sectional study of the retinal nerve fiber layer thickness at 7 years after an acute episode of unilateral primary acute angle closure.  

PubMed

The purpose of this article is to investigate the long-term retinal nerve fiber layer (RNFL) status and determinants of RNFL thinning after an episode of unilateral primary acute angle closure (AAC). This cross-sectional study analyzed the medical records of consecutive patients with a single episode of unilateral AAC from 1999 to 2009 in Hong Kong. The peripapillary RNFL thickness was correlated with age, gender, presenting intraocular pressure (IOP), time to laser iridotomy, time to cataract extraction, follow-up duration, as well as the last IOP, vertical cup-to-disc ratio (CDR), and vision. The fellow uninvolved eye was used as a proxy comparison of RNFL loss in the attack eye. In 40 eligible patients, the mean age was 68.3 ± 8.7 years with a male-to-female ratio of 1:7. The mean presenting IOP was 49.2 ± 14.0 mm Hg and the time from presentation to laser iridotomy was 6.7 ± 6.9 days. Forty percent of subjects received a cataract extraction at 3.2 ± 2.9 years after the attack. The last IOP, CDR, and LogMAR vision were 16.0 ± 3.8 mm Hg, 0.6 ± 0.2, and 0.6 ± 0.6 LogMAR units, respectively, at 7.9 ± 2.4 years. The RNFL thickness in the attack eye (69.2 ± 19.1 ?m) was 25.2 ± 17.9% thinner than the fellow eye (93.0 ± 17.8 ?m) at 7.5 ± 2.9 years post-AAC. Using univariate analysis, the last vertical CDR (odds ratio [OR]?= 17.2, P = 0.049) and LogMAR visual acuity (VA) (OR = 6.6, P = 0.03) were the only significant predictors for RNFL thinning whereas none of the other covariates showed significant associations (P > 0.1). At 7.5 years following unilateral AAC, the RNFL thickness was 25% thinner than the fellow eye. CDR enlargement and poor VA were the only significant predictors for RNFL loss. PMID:25590844

Lee, Jacky W Y; Woo, Tiffany T Y; Yau, Gordon S K; Yip, Stan; Yick, Doris W F; Wong, Jasper; Wong, Raymond L M; Wong, Ian Y H

2015-01-01

167

Reproduction of wild birds via interspecies germ cell transplantation.  

PubMed

The present study was conducted to apply an interspecies germ cell transfer technique to wild bird reproduction. Pheasant (Phasianus colchicus) primordial germ cells (PGCs) retrieved from the gonads of 7-day-old embryos were transferred to the bloodstream of 2.5-day-old chicken (Gallus gallus) embryos. Pheasant-to-chicken germline chimeras hatched from the recipient embryos, and 10 pheasants were derived from testcross reproduction of the male chimeras with female pheasants. Gonadal migration of the transferred PGCs, their involvement in spermatogenesis, and production of chimeric semen were confirmed. The phenotype of pheasant progenies derived from the interspecies transfer was identical to that of wild pheasants. The average efficiency of reproduction estimated from the percentage of pheasants to total progenies was 17.5%. In conclusion, interspecies germ cell transfer into a developing embryo can be used for wild bird reproduction, and this reproductive technology may be applicable in conserving endangered bird species. PMID:18685127

Kang, Seok Jin; Choi, Jin Won; Kim, Sun Young; Park, Kyung Je; Kim, Tae Min; Lee, Young Mok; Kim, Heebal; Lim, Jeong Mook; Han, Jae Yong

2008-11-01

168

The Galactic Ecosystems Research and Mentorship (GERM) Initiative  

NASA Astrophysics Data System (ADS)

The Galactic Ecosystems Research and Mentorship (GERM) Initiative was established as a means of catalyzing engagement of Tufts University students in research and education relating to the inner workings of star-forming galaxies such as our own Milky Way galaxy. To date, the GERM Initiative has led to the creation of a seminar course on Galactic Ecosystems at Tufts, multiple papers and presentations by experts and students which are archived at http://go.tufts.edu/galacticecosystems, research collaborations at the Harvard-Smithsonian Center for Astrophysics, and an emerging relationship with the Clay Center Observatory to carry out narrowband imaging of galactic star-forming regions. We are grateful for funding support from the Massachusetts Space Grant Consortium and the AAS Small Research Grant Program. Pending further support, the GERM Initiative could be expanded to involve a significantly larger cohort of students and researchers in the Boston area.

Waller, William H.

2009-01-01

169

Fetal germ cell differentiation and the impact of the somatic cells   

E-print Network

Specification of a germ cell lineage and appropriate maturation are essential for the transfer of genetic information from one generation to the next. Germ cells form from pluripotent precursor cells that migrate into ...

Cowan, Gillian

2009-01-01

170

The role of retinoic acid in germ cell development in embryonic mouse gonads  

E-print Network

Germ cells are the only cell type to undergo meiosis, a specialized cell division process necessary for the formation of haploid gametes. Timing of this process is sex-specific. Ovarian germ cells initiate meiosis during ...

Koubová, Jana C

2007-01-01

171

FLI-1 Flightless-1 and LET-60 Ras control germ line morphogenesis in C. elegans  

E-print Network

Glm phenotype, suggesting that LET-60 Ras and FLI-1 might act together to control germ line morphogenesis. Conclusion: FLI-1 controls germ line morphogenesis and rachis organization, a process about which little is known at the molecular level...

Lu, Jiamiao; Dentler, William L., Jr; Lundquist, Erik A.

2008-05-16

172

The function of RNA Binding Protein 9 in germ cell differentiation in Drosophila ovary  

E-print Network

Germ cell development is an essential process to ensure continuity of species. Drosophila oogenesis has long been served as a model system to study germ cell development. Previously, the Elav-Hu family protein RNA-binding ...

Yao, Min

2013-12-31

173

Everolimus and Letrozole in Treating Patients With Recurrent Hormone Receptor Positive Ovarian, Fallopian Tube, or Primary Peritoneal Cavity Cancer  

ClinicalTrials.gov

Ovarian Endometrioid Adenocarcinoma; Ovarian Mixed Epithelial Carcinoma; Ovarian Papillary Serous Carcinoma; Ovarian Serous Cystadenocarcinoma; Ovarian Undifferentiated Adenocarcinoma; Recurrent Fallopian Tube Cancer; Recurrent Ovarian Epithelial Cancer; Recurrent Ovarian Germ Cell Tumor; Recurrent Primary Peritoneal Cavity Cancer

2014-12-02

174

Chiral discotic columnar germs of nucleosome core particles.  

PubMed Central

In concentrated solution and in the presence of high concentrations of monovalent cations, nucleosome core particles order into a discotic columnar mesophase. This phase is limited to finite-sized hexagonal germs that further divide into six coiled branches, following an iterative process. We show how the structure of the germs comes from the competition between hexagonal packing and chirality with a combination of dendritic facetting and double-twist configurations. Geometrical considerations lead us to suspect that the chirality of the eukaryotic chromosomes may originate from the same competition. PMID:10777768

Livolant, F; Leforestier, A

2000-01-01

175

Retroperitoneal teratoma with somatic malignant transformation: A papillary renal cell carcinoma in a testicular germ cell tumour metastasis following platinum-based chemotherapy  

PubMed Central

Background Malignant transformation describes the phenomenon in which a somatic component of a germ cell teratoma undergoes malignant differentiation. A variety of different types of sarcoma and carcinoma, all non-germ cell, have been described as a result of malignant transformation. Case presentation A 33-year-old man presented with a left testicular mass and elevated tumour markers. Staging investigations revealed retroperitoneal lymphadenopathy with obstruction of the left ureter and distant metastases. Histopathology from the left radical orchiectomy showed a mixed germ cell tumour (Stage III, poor prognosis). The ureter was stented and four cycles of cisplatin, etoposide and bleomycin chemotherapy administered. After initial remission, the patient recurred four years later with a large retroperitoneal mass involving the renal vessels and the left ureter. Left retroperitoneal lymph node dissection with en-bloc resection of the left kidney was performed. Histopathology revealed a germ cell tumour metastasis consisting mainly of mature teratoma. Additionally, within the teratoma a papillary renal cell carcinoma was found. The diagnosis was supported by immunohistochemistry showing positivity for AMACR, CD10 and focal expression of RCC and CK7. There was no radiological or histo-pathological evidence of a primary renal cell cancer. Conclusions To the best of our knowledge, malignant transformation into a papillary renal cell carcinoma has not been reported in a testicular germ cell tumour metastasis following platinum-based chemotherapy. This histological diagnosis might have implications for potential future therapies. In the case of disease recurrence, renal cell cancer as origin of the recurrent tumour has to be excluded because renal cell carcinoma metastases would not respond well to the classical germ cell tumour chemotherapy regimens. PMID:23402579

2013-01-01

176

The role of the sex chromosomes in mammalian germ cell differentiation  

E-print Network

The role of the sex chromosomes in mammalian germ cell differentiation P. S. BURGOYNE Department. An analysis is presented of the relationship between abnormalities of mamma- lian germ cell differentiation and their sex-chromosomal make-up. It is concluded that germ cells in an ovary require two functional X

Paris-Sud XI, Université de

177

Regulative germ cell specification in axolotl embryos: a primitive trait conserved in the mammalian lineage.  

PubMed Central

How germ cells are specified in the embryos of animals has been a mystery for decades. Unlike most developmental processes, which are highly conserved, embryos specify germ cells in very different ways. Curiously, in mouse embryos germ cells are specified by extracellular signals; they are not autonomously specified by maternal germ cell determinants (germ plasm), as are the germ cells in most animal model systems. We have developed the axolotl (Ambystoma mexicanum), a salamander, as an experimental system, because classic experiments have shown that the germ cells in this species are induced by extracellular signals in the absence of germ plasm. Here, we provide evidence that the germ cells in axolotls arise from naive mesoderm in response to simple inducing agents. In addition, by analysing the sequences of axolotl germ-cell-specific genes, we provide evidence that mice and urodele amphibians share a common mechanism of germ cell development that is ancestral to tetrapods. Our results imply that germ plasm, as found in species such as frogs and teleosts, is the result of convergent evolution. We discuss the evolutionary implications of our findings. PMID:14511484

Johnson, Andrew D; Crother, Brian; White, Mary E; Patient, Roger; Bachvarova, Rosemary F; Drum, Matthew; Masi, Thomas

2003-01-01

178

Protein in wet-milled corn germ recovered by ultrafiltration-diafiltration  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study was conducted to evaluate ultrafiltration-diafiltration (UF-DF) as a means to improve the extractability of wet-milled corn germ protein and determine its effects on the functional properties of the recovered protein product. Wet germ and finished (dried) germ proteins were extracted by u...

179

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri)  

E-print Network

Changes in the number of germ cells in the gonads of the rainbow trout (Salmo gairdneri) during-hatching weeks, two groups of fish could be distinguished by the number of their germ cells (G2) - one group had). The gonads of the other fish stayed at the indifferent stage. The number of germ cells was significantly

Paris-Sud XI, Université de

180

DNA Analysis in Samples From Younger Patients With Germ Cell Tumors and Their Parents or Siblings  

ClinicalTrials.gov

Childhood Malignant Ovarian Germ Cell Tumor; Childhood Malignant Testicular Germ Cell Tumor; Ovarian Choriocarcinoma; Ovarian Embryonal Carcinoma; Ovarian Mixed Germ Cell Tumor; Ovarian Teratoma; Ovarian Yolk Sac Tumor; Testicular Choriocarcinoma; Testicular Embryonal Carcinoma; Testicular Seminoma; Testicular Teratoma; Testicular Yolk Sac Tumor

2014-02-17

181

Transplantation of Germ Line Stem Cells for the Study and Manipulation of Spermatogenesis  

Microsoft Academic Search

Transplantation of male germ line stem cells from a fertile donor to the testis of an infertile recipient restores donor-derived spermatogenesis in the recipient testis and the resulting sperm pass the donor genotype to the offspring of the recipient. Germ cell transplantation has been an invaluable tool to elucidate the biology of male germ line stem cells and their niche

I. Dobrinski

182

The meiosis inducing interaction between germ cells and rete cells in the fetal mouse gonad  

E-print Network

The meiosis inducing interaction between germ cells and rete cells in the fetal mouse gonad Anne., Denmark. Introduction. In the mammalian gonad the onset of meiosis of the female germ cells occurs much earlier in life than meiosis of the male germ cells. In the ovary we know that both the differentiation

Paris-Sud XI, Université de

183

A zebrafish homologue of the chemokine receptor Cxcr4 is a germ-cell guidance receptor  

Microsoft Academic Search

Germ cells preserve an individual's genetic information and transmit it to the next generation. Early in development germ cells are set aside and undergo a specialized developmental programme, a hallmark of which is the migration from their site of origin to the future gonad. In Drosophila, several factors have been identified that control germ-cell migration to their target tissues; however,

Holger Knaut; Christian Werz; Robert Geisler; Christiane Nüsslein-Volhard

2003-01-01

184

USING MICROWAVE HEATING TO DETERMINE OPTIMAL CORN GERM OIL YIELD WITH A BENCH-SCALE PRESS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Methods have been proposed recently to separate germ from corn prior to fermentation to improve dry grind ethanol process economic return. Oil would be extracted from the germ and sold as a separate product. It is not clear that available methods to extract oil from this germ are economically pra...

185

GAGE Cancer-Germline Antigens Are Recruited to the Nuclear Envelope by Germ Cell-Less (GCL)  

PubMed Central

GAGE proteins are highly similar, primate-specific molecules with unique primary structure and undefined cellular roles. They are restricted to cells of the germ line in adult healthy individuals, but are broadly expressed in a wide range of cancers. In a yeast two-hybrid screen we identified the metazoan transcriptional regulator, Germ cell-less (GCL), as an interaction partner of GAGE12I. GCL directly binds LEM-domain proteins (LAP2?, emerin, MAN1) at the nuclear envelope, and we found that GAGE proteins were recruited to the nuclear envelope inner membrane by GCL. Based on yeast two-hybrid analysis and pull-down experiments of GCL polypeptides, GCL residues 209–320 (which includes the BACK domain) were deduced sufficient for association with GAGE proteins. GAGE mRNAs and GCL mRNA were demonstrated in human testis and most types of cancers, and at the protein level GAGE members and GCL were co-expressed in cancer cell lines. Structural studies of GAGE proteins revealed no distinct secondary or tertiary structure, suggesting they are intrinsically disordered. Interestingly GAGE proteins formed stable complexes with dsDNA in vitro at physiological concentrations, and GAGE12I bound several different dsDNA fragments, suggesting sequence-nonspecific binding. Dual association of GAGE family members with GCL at the nuclear envelope inner membrane in cells, and with dsDNA in vitro, implicate GAGE proteins in chromatin regulation in germ cells and cancer cells. PMID:23029259

Gjerstorff, Morten F.; Rösner, Heike I.; Pedersen, Christina B.; Greve, Katrine B. V.; Schmidt, Steffen; Wilson, Katherine L.; Mollenhauer, Jan; Besir, Hüseyin; Møllegaard, Niels Erik; Ditzel, Henrik J.

2012-01-01

186

Mechanisms guiding primordial germ cell migration: strategies from different organisms  

Microsoft Academic Search

The regulated migration of cells is essential for development and tissue homeostasis, and aberrant cell migration can lead to an impaired immune response and the progression of cancer. Primordial germ cells (PGCs), precursors to sperm and eggs, have to migrate across the embryo to reach somatic gonadal precursors, where they carry out their function. Studies of model organisms have revealed

Brian E. Richardson; Ruth Lehmann

2010-01-01

187

Expression of HSP86 in male germ cells.  

PubMed Central

A comparison of HSP84 and HSP86 mRNA expression in adult mouse tissues revealed distinct expression patterns for these highly homologous genes. Particularly striking is the germ cell specificity of HSP86 expression in the testis, suggesting distinct roles for HSP84 and HSP86 with respect to testicular function and development. Images PMID:2342473

Lee, S J

1990-01-01

188

GERM CELLS AND SEX DIFFERENTIATION IN LEBISTES RETICULATUS  

Microsoft Academic Search

In this paper there is presented a condensed account of the results of a series of studies begun in our laboratory three years ago which deals chiefly with the history of the germ cells in Lebistes reticulatus and the correlation of that history with the secondary sex characters. In so far as the results closely parallel those obtained on other

H. B. GOODRICH; J. E. DEE; C. M. FLYNN; ROWENA N. MERCER

189

Composition and Molecular Weight Distribution of Carob Germ Proteins Fractions  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biochemical properties of carob germ proteins were analyzed using a combination of selective extraction, reversed-phase high performance liquid chromatography (RP-HPLC), size exclusion chromatography coupled with multi-angle laser light scattering (SEC-MALS) and electrophoretic analysis. Using a mo...

190

Everyday Preventive Actions That Can Help Fight Germs, Like Flu  

E-print Network

Everyday Preventive Actions That Can Help Fight Germs, Like Flu CDC recommends a three-step approach to fighting the flu. CDC recommends a three-step approach to fighting influenza (flu). The first and most important step is to get a flu vaccination each year. But if you get the flu

Tipple, Brett

191

AQUEOUS ENZYMATIC EXTRACTION OF CORN OIL FROM CORN GERM  

Technology Transfer Automated Retrieval System (TEKTRAN)

ABSTRACT Currently all commercial corn oil is obtained from corn germ by either hexane extraction, or a process that combines pressing/hexane extraction. Because of the safety and environmental issues associated with the use of hexane, the construction and operational costs of hexane extraction fac...

192

Preschoolers' Understanding of Germs as Causes of Illness.  

ERIC Educational Resources Information Center

Two studies examined preschoolers' understanding of germs as causes of illness. Previous research suggests that preschoolers know that certain behaviors lead to illness without understanding why or how. In the first study, 22 children between 4 and 5 years old were presented with 12 brief stories describing characters engaged in either dangerous…

Kalish, Charles

193

E. Coli Germs Found on Farmers Market Herbs  

MedlinePLUS

... sharing features on this page, please enable JavaScript. E. Coli Germs Found on Farmers Market Herbs Nearly one- ... Preidt Friday, December 19, 2014 Related MedlinePlus Pages E. Coli Infections Food Safety FRIDAY, Dec. 19, 2014 (HealthDay ...

194

Declaring the Existence of Human Germ-Cell Mutagens  

EPA Science Inventory

After more than 80 years of searching for human germ-cell mutagens, I think that sufficient evidence already exists for a number of agents to be so considered, and definitive confirmation seems imminent due to the application ofrecently developed genomic techniques. In preparatio...

195

Treatment of nonretroperitoneal residual germ cell tumor masses  

Microsoft Academic Search

The appropriate treatment of residual disease outside the retroperitoneum after chemotherapy is a crucial component of the comprehensive approach to treating advanced testicular germ cell tumors (GCT). Residual nonretroperitoneal disease is most commonly found in the thorax but can also be identified in other sites, including the neck, liver, and brain. Although some data suggest that certain variables such as

Mark H. Katz; James M. McKiernan

2005-01-01

196

Of Germ Cells, Trophoblasts, and Cancer Stem Cells  

Microsoft Academic Search

The trophoblastic theory of cancer, proposed in the early 1900s by Dr John Beard, may not initially seem relevant to current cancer models and treatments. However, the underpinnings of this theory are remarkably similar to those of the cancer stem cell (CSC) theory. Beard noticed that a significant fraction of germ cells never reach their final destination as they migrate

Angela R. Burleigh

2008-01-01

197

A Method for Cryopreserving Chicken Primordial Germ Cells  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study established a method for preserving chicken primordial germ cells (PGCs) that enables long-term storage in liquid nitrogen. Gonads were harvested from stage 27 chick embryos and pooled in groups of 5 (5E), 10 (10E), or 20 (20E) embryos contributing gonads to the cell suspension. The gona...

198

Prenatal exposure to chromium induces early reproductive senescence by increasing germ cell apoptosis and advancing germ cell cyst breakdown in the F1 offspring.  

PubMed

Hexavalent chromium (CrVI), one of the more toxic heavy metals, is widely used in more than 50 industries such as chrome plating, welding, wood processing and tanneries. As one of the world's leading producers of chromium compounds, the U.S. is facing growing challenges in protecting human health against multiple adverse effects of CrVI. CrVI is rapidly converted to CrIII intracellularly, and can induce apoptosis through different mechanisms. Our previous studies demonstrated postnatal exposure to CrVI results in a delay or arrest in follicle development and puberty. Pregnant rats were treated with 25 ppm potassium dichromate (CrVI) from gestational day (GD) 9.5 to 14.5 through drinking water, placentae were removed on GD 20, and total Cr was estimated in the placentae; ovaries were removed from the F1 offspring on postnatal day (PND)-1 and various analyses were performed. Our results show that gestational exposure to CrVI resulted in (i) increased Cr concentration in the placenta, (ii) increased germ cell apoptosis by up-regulating p53/p27-Bax-caspase-3 proteins and by increasing p53-SOD-2 co-localization; (iii) accelerated germ cell cyst (GCC) breakdown; (iv) advanced primordial follicle assembly and primary follicle transition and (v) down regulation of p-AKT, p-ERK and XIAP. As a result of the above events, CrVI induced early reproductive senescence and decrease in litter size in F1 female progeny. PMID:24530425

Sivakumar, Kirthiram K; Stanley, Jone A; Arosh, Joe A; Pepling, Melissa E; Burghardt, Robert C; Banu, Sakhila K

2014-04-01

199

Selective accumulation of germ-line associated gene products in early development of the sea star and distinct differences from germ-line development in the sea urchin  

PubMed Central

Background Echinodermata is a diverse Phylum, a sister group to chordates, and contains diverse organisms that may be useful to understand varied mechanisms of germ-line specification. Results We tested 23 genes in development of the sea star Patiria miniata that fall into five categories: 1) Conserved germ-line factors; 2) Genes involved in the inductive mechanism of germ-line specification; 3) Germ-line associated genes; 4) Molecules involved in left-right asymmetry; and 5) Genes involved in regulation and maintenance of the genome during early embryogenesis. Overall, our results support the contention that the posterior enterocoel is a source of the germ line in the sea star P. miniata. Conclusion The germ line in this organism appears to be specified late in embryogenesis, and in a pattern more consistent with inductive interactions amongst cells. This is distinct from the mechanism seen in sea urchins, a close relative of the sea star clad. We propose that P. miniata may serve as a valuable model to study inductive mechanisms of germ-cell specification and when compared to germ-line formation in the sea urchin S. purpuratus may reveal developmental transitions that occur in the evolution of inherited and inductive mechanisms of germ-line specification. PMID:24038550

Fresques, Tara; Zazueta-Novoa, Vanesa; Reich, Adrian; Wessel, Gary M.

2014-01-01

200

Interaction of Azospirillum lipoferum with Wheat Germ Agglutinin Stimulates Nitrogen Fixation  

PubMed Central

In vitro, the nitrogen fixation capability of A. lipoferum is efficiently increased in the presence of wheat germ agglutinin (WGA). A putative WGA-binding receptor, a 32-kDa protein, was detected in the cell capsule. The stimulatory effect required N-acetyl-d-glucosamine dimer (GlcNAcdi) terminated sugar side chains of the receptor and was dependent on the number of GlcNAcdi links involved in receptor-WGA interface. Binding to the primary sugar binding sites on WGA had a larger stimulatory effect than binding to the secondary sites. The WGA-receptor complex generated stimulus led to elevated transcription of the nifH and nifA genes and of the glnBA gene cluster but not of the glnA gene from its own promoter. There may well be a signalling cascade contributing to the regulation of nitrogen fixation. PMID:10383962

Karpati, Eva; Kiss, Peter; Ponyi, Tamas; Fendrik, Istvan; de Zamaroczy, Miklos; Orosz, Laszlo

1999-01-01

201

Anastomosis of germ tubes and nuclear migration of nuclei in germ tube networks of the soybean rust pathogen, Phakopsora pachyrhizi  

Technology Transfer Automated Retrieval System (TEKTRAN)

Parasexual recombination through hyphal anastomosis is an important mechanism for genetic diversity in filamentous fungi. In this study, we observed fusion of germ tubes in germinating urediniospores of Phakopsora pachyrhizi resulting in a complex hyphal network. Staining of the germinating uredinio...

202

The Fragilis interferon-inducible gene family of transmembrane proteins is associated with germ cell specification in mice  

Microsoft Academic Search

BACKGROUND: Specification of primordial germ cells in mice depends on instructive signalling events, which act first to confer germ cell competence on epiblast cells, and second, to impose a germ cell fate upon competent precursors. fragilis, an interferon-inducible gene coding for a transmembrane protein, is the first gene to be implicated in the acquisition of germ cell competence. RESULTS: Here,

M Saitou; SC Barton; MA Surani

2003-01-01

203

Identification of X-Linked Genes Required for Migration and Programmed Cell Death of Drosophila melanogaster Germ Cells  

Microsoft Academic Search

Drosophila germ cells form at the posterior pole of the embryo and migrate to the somatic gonad. Approximately 50% of the germ cells that form reach their target. The errant cells within the embryo undergo developmentally regulated cell death. Prior studies have identified some autosomal genes that regulate germ cell migration, but the genes that control germ cell death are

Clark R. Coffman; Rachel C. Strohm; Fredrick D. Oakley; Yukiko Yamada; Danielle Przychodzin; Robert E. Boswell

204

Sexual differentiation of germ cells in XX mouse gonads occurs in an anterior-to-posterior wave  

Microsoft Academic Search

Differentiation of mouse embryonic germ cells as male or female is dependent on the somatic environment of the gonad rather than the sex chromosome constitution of the germ cell. However, little is known about the initiation of germ cell sexual differentiation. Here, we traced the initiation of germ cell sexual differentiation in XX gonads using the Stra8 gene, which we

Douglas B. Menke; Jana Koubova; David C. Page

2003-01-01

205

In Search of a Germ Theory Equivalent for Chronic Disease  

PubMed Central

The fight against infectious disease advanced dramatically with the consolidation of the germ theory in the 19th century. This focus on a predominant cause of infections (ie, microbial pathogens) ultimately led to medical and public health advances (eg, immunization, pasteurization, antibiotics). However, the resulting declines in infections in the 20th century were matched by a rise in chronic, noncommunicable diseases, for which there is no single underlying etiology. The discovery of a form of low-grade systemic and chronic inflammation (“metaflammation”), linked to inducers (broadly termed “anthropogens”) associated with modern man-made environments and lifestyles, suggests an underlying basis for chronic disease that could provide a 21st-century equivalent of the germ theory. PMID:22575080

2012-01-01

206

Switching stem cell state through programmed germ cell reprogramming.  

PubMed

Depending on their origin, embryo-derived stem cells have distinct properties that largely correspond to their counterpart in vivo. Mouse epiblast stem cells derived from post-implantation embryos differ from embryonic stem cells derived from blastocysts in their transcriptional and epigenetic profile, their morphology and culture requirements. When maintained in appropriate conditions, the cells keep self-renewing and do not adopt a different state. Recent studies, however, show that it is possible to convert between stem cell states. Here we review recent advances to induce stem cell state changes and we consider the potential of germ cell-mediated reprogramming for the conversion. Since the properties of mouse epiblast stem cells are similar to human embryonic stem cells, we discuss the significance of stem cell conversion and germ cell-mediated reprogramming in humans. PMID:21330045

Gillich, Astrid; Hayashi, Katsuhiko

2011-06-01

207

Germ plasm in Eleutherodactylus coqui, a direct developing frog with large eggs  

PubMed Central

Background RNAs for embryo patterning and for germ cell specification are localized to the vegetal cortex of the oocyte of Xenopus laevis. In oocytes of the direct developing frog Eleutherodactylus coqui, orthologous RNAs for patterning are not localized, raising the question as to whether RNAs and other components of germ plasm are localized in this species. Methods To identify germ plasm, E. coqui embryos were stained with DiOC6(3) or examined by in situ hybridization for dazl and DEADSouth RNAs. The cDNAs for the E. coqui orthologues were cloned by RT-PCR using degenerate primers. To examine activity of the E. coqui orthologues, RNAs, made from constructs of their 3'UTRs with mCherry, were injected into X. laevis embryos. Results Both DiOC6(3) and dazl and DEADSouth in situs identified many small islands at the vegetal surface of cleaving E. coqui embryos, indicative of germ plasm. Dazl was also expressed in primordial germ cells in the genital ridge. The 3'UTRs of E. coqui dazl and DEADSouth directed primordial germ cell specific protein synthesis in X. laevis. Conclusions E. coqui utilizes germ plasm with RNAs localized to the vegetal cortex to specify primordial germ cells. The large number of germ plasm islands suggests that an increase in the amount of germ plasm was important in the evolution of the large E. coqui egg. PMID:21978790

2011-01-01

208

Germ cell development in the Honeybee (Apis mellifera); Vasa and Nanos expression  

PubMed Central

Background Studies of specification of germ-cells in insect embryos has indicated that in many taxa the germ cells form early in development, and their formation is associated with pole plasm, germ plasm or an organelle called the oosome. None of these morphological features associated with germ cell formation have been identified in the Honeybee Apis mellifera. In this study I report the cloning and expression analysis of Honeybee homologues of vasa and nanos, germ cell markers in insects and other animals. Results Apis vasa and nanos RNAs are present in early honeybee embryos, but the RNAs clear rapidly, without any cells expressing these germ cell markers past stage 2. These genes are then only expressed in a line of cells in the abdomen from stage 9 onwards. These cells are the developing germ cells that are moved dorsally by dorsal closure and are placed in the genital ridge. Conclusion This study of the expression of germ cell markers in the honeybee implies that in this species either germ cells are formed by an inductive event, late in embryogenesis, or they are formed early in development in the absence of vasa and nanos expression. This contrasts with germ cell development in other members of the Hymenoptera, Diptera and Lepidoptera. PMID:16503992

Dearden, Peter K

2006-01-01

209

Sex determination of the Drosophila germ line: tra and dsx control somatic inductive signals.  

PubMed

In Drosophila, the sex of germ cells is determined by cell-autonomous and inductive signals. XY germ cells autonomously enter spermatogenesis when developing in a female host. In contrast, XX germ cells non-autonomously become spermatogenic when developing in a male host. In first instar larvae with two X chromosomes, XX germ cells enter the female or the male pathway depending on the presence or absence of transformer (tra) activity in the surrounding soma. In somatic cells, the product of tra regulates the expression of the gene double sex (dsx) which can form a male-specific or a female-specific product. In dsx mutant larvae, XX and XY germ cells develop abnormally, with a seemingly intersexual phenotype. This indicates that female-specific somatic dsx products feminize XX germ cells, and male-specific somatic dsx products masculinize XX and XY germ cells. The results show that tra and dsx control early inductive signals that determine the sex of XX germ cells and that somatic signals also affect the development of XY germ cells. XX germ cells that develop in pseudomales lacking the sex-determining function of Sxl are spermatogenic. If, however, female-specific tra functions are expressed in these animals, XX germ cells become oogenic. Furthermore, transplanted XX germ cells can become oogenic and form eggs in XY animals that express the female-specific function of tra. Therefore, TRA product present in somatic cells of XY animals or in animals lacking the sex-determining function of Sxl, is sufficient to support developing XX germ cells through oogenesis. PMID:8162863

Steinmann-Zwicky, M

1994-03-01

210

Germ cell transplantation: A potential treatment of severe testicular failure  

Microsoft Academic Search

Although the process of spermatogenesis is relatively efficient and resistant to damage, male infertility can result from\\u000a exposure to toxic agents such as chemotherapeutic regimes, radiation, or occupational exposures to chemicals. Other types\\u000a of infertility may result from migratory defects or poor survival of primordial germ cells during development, abnormal repopulation\\u000a of the tubules by spermatogonia during development, or low

David J. Cozzolino; Dolores J. Lamb

2000-01-01

211

The role of testicular germ cell apoptosis during equine spermatogenesis  

E-print Network

a single stallion, c. Confirm low molecular weight (mw) DNA fragmentation using the ladder assay, and d. Ultrastructural analysis of apoptotic germ cells. 3 2. Develop methodology and criteria to stage the equine seminiferous epithelium... forming small vacuoles in the area of the developing tubule lumen [11,12] forming what will be ducts to transport mature spermatozoa from their site of production in the seminiferous tubule to the epididymis. Spermatogenesis in the mature stallion...

Heninger, Noah Leland, III

2007-04-25

212

High-dose chemotherapy in germ-cell tumors  

Microsoft Academic Search

Summary The majority of patients with advanced-stage germ-cell tumor are curable by cisplatin-bas ed chemotherapy, but about 10% of those in the good-risk and 30%-50% in the poor-risk groups will experience relapse. Patients in first relapse have a 60% chance of entering a second complete remission and a 15%-25% probability that it will be durable. Regimens of high-dose chemotherapy with

J. P. Droz; S. Culine; P. Biron; A. Kramar

213

Spinel inclusions in olivine and plagioclase crystals in a layered gabbro: a marker and a tracer for primary phenocrysts in a differentiating magma reservoir  

NASA Astrophysics Data System (ADS)

The problem of whether cumulate rocks were formed by crystal settling or by in situ crystallization after magma emplacement is an important issue concerning the mechanisms of magmatic differentiation. However, it is hard to distinguish these two processes for plutonic rocks because the primary texture and chemical composition have generally been modified by postcumulus processes. To contribute this problem, we studied the distribution and compositions of Cr-spinel inclusions hosted in olivine and plagioclase in the Murotomisaki Gabbroic Intrusion (MGI), SW Japan. It is shown that the olivine-hosted inclusions are restricted to specific horizons where accumulation of olivine phenocrysts is thought to have occurred and that the compositional variations of the Cr-spinel are explained by a secondary compositional modification that probably took place after the magma emplacement. It is also shown that the Cr-spinel inclusions in a chilled margin have suffered the least compositional modification and nearly retains the primary composition. Those in the interior of the intrusion, on the contrary, have been significantly modified by re-equilibration with residual melt driven by cation diffusions through the host phases. Those in plagioclase have been less modified. It is shown that all the spinel inclusions had primarily the same and common composition at the time of magma emplacement. This implies that all the inclusion-bearing crystals, olivine and plagioclase, represent primary phenocrysts that had already existed in the emplaced magma. In this way, spinel inclusion in the MGI may be regarded to be a useful petrographic "marker" for identifying intratelluric phenocrysts and also as a "tracer" to trace the motion of the primary phenocrysts after the magma emplacement.

Hoshide, Takashi; Obata, Masaaki

2014-08-01

214

[Effects of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) on the formation of dental hard tissue of mouse molar tooth germs in organ culture system].  

PubMed

In the developing tooth, 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) causes hypoplasia and hypomineralization of enamel and dentine. The present study was undertaken to clarify the effects of HEBP on the formation of dental tissues of tooth germs in an organ culture system. Mandibular first molars from 17.5-day-old mouse embryos were cultured with or without 250 microM HEBP in culture medium. Cultured tooth germs were analyzed by histological examination and by immunohistochemical localization using anti-amelogenin antibody. In cultured tooth germs treated with HEBP before the commencement of calcification in dentine, calcification of dentine matrix was inhibited completely and enamel formation was not observed. Ameloblasts were directly adjacent to dentine matrix. However, immunohistochemical data indicated that these ameloblasts secreted amelogenin. In the experiments of adding HEBP to cultured tooth germs on culture day 13, calcified dentine and enamel had formed before the administration of HEBP, but the dentine matrix newly formed after the administration of HEBP had not calcified. It was confirmed by immunohistochemical observations that enamel matrix-like material had penetrated into uncalcified dentine matrix and accumulated in dental papilla of tooth germs. However, no enamel matrix-like material was observed in calcified dentine and predentine underneath the calcified dentine by immunohistochemical staining. From these results, it might be concluded that ameloblasts secreted enamel matrix in the presence of HEBP and diffused through uncalcified dentine matrix into dental papilla. These findings suggests the calcification of dentine might be essential for the physical barrier to accumulate the enamel matrix and form a distinct layer of enamel as enamel. PMID:12872747

Tsuyoshi, Daigo

2003-06-01

215

Generation of germ-line chimera zebrafish using primordial germ cells isolated from cultured blastomeres and cryopreserved embryoids.  

PubMed

Primordial germ cells (PGCs) are the only cells in developing embryos with the potential to transmit genetic information to the next generation. In our previous study, a single PGC transplanted into a host differentiated into fertile gametes and produced germ-line chimeras of cyprinid fish, including zebrafish. In this study, we aimed to induce germ-line chimeras by transplanting donor PGCs from various sources (normal embryos at different stages, dissociated blastomeres, embryoids, or embryoids cryopreserved by vitrification) into host blastulae, and compare the migration rates of the PGCs towards the gonadal ridge. Isolated, cultured blastomeres not subject to mesodermal induction were able to differentiate into PGCs that retained their motility. Moreover, these PGCs successfully migrated towards the gonadal ridge of the host and formed viable gametes. Motility depended on developmental stage and culture duration: PGCs obtained at earlier developmental stages and with shorter cultivation periods showed an increased rate of migration to the gonadal ridge. Offspring were obtained from natural spawning between normal females and chimeric males. These results provide the basis for new methods of gene preservation in zebrafish. PMID:21302258

Kawakami, Yutaka; Goto-Kazeto, Rie; Saito, Taiju; Fujimoto, Takafumi; Higaki, Shogo; Takahashi, Yoshiyuki; Arai, Katsutoshi; Yamaha, Etsuro

2010-01-01

216

Risk and prognostic significance of metachronous contralateral testicular germ cell tumours  

PubMed Central

Background: Testicular germ cell tumour (TGCT) patients are at increased risk of developing a contralateral testicular germ cell tumour (CTGCT). It is unclear whether TGCT treatment affects CTGCT risk. Methods: The risk of developing a metachronous CTGCT (a CTGCT diagnosed ?6 months after a primary TGCT) and its impact on patient's prognosis was assessed in a nationwide cohort comprising 3749 TGCT patients treated in the Netherlands during 1965–1995. Standardised incidence ratios (SIRs), comparing CTGCT incidence with TGCT incidence in the general population, and cumulative CTGCT incidence were estimated and CTGCT risk factors assessed, accounting for competing risks. Results: Median follow-up was 18.5 years. Seventy-seven metachronous CTGCTs were diagnosed. The SIR for metachronous CTGCTs was 17.6 (95% confidence interval (95% CI) 13.9–22.0). Standardised incidence ratios remained elevated for up to 20 years, while the 20-year cumulative incidence was 2.2% (95% CI 1.8–2.8%). Platinum-based chemotherapy was associated with a lower CTGCT risk among non-seminoma patients (hazard ratio 0.37, 95% CI 0.18–0.72). The CTGCT patients had a 2.3-fold (95% CI 1.3–4.1) increased risk to develop a subsequent non-TGCT cancer and, consequently, a 1.8-fold (95% CI 1.1–2.9) higher risk of death than patients without a CTGCT. Conclusion: The TGCT patients remain at increased risk of a CTGCT for up to 20 years. Treatment with platinum-based chemotherapy reduces this risk. PMID:23059747

Schaapveld, M; van den Belt-Dusebout, A W; Gietema, J A; de Wit, R; Horenblas, S; Witjes, J A; Hoekstra, H J; Kiemeney, L A L M; Louwman, W J; Ouwens, G M; Aleman, B M P; van Leeuwen, F E

2012-01-01

217

Retinoic acid induces mouse bone marrow-derived CD15?, Oct4? and CXCR4? stem cells into male germ-like cells in a two-dimensional cell culture system.  

PubMed

We have examined the effect of retinoic acid (RA) on differentiation of bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells into male germ cells. Bone marrow stem cells (BMSCs) were isolated from the femur of 3-4-week-old male C57BL/6 mice. Magnetic-activated cell sorting (MACS) system was used to sort CD15(+) , Oct4(+) and CXCR4(+) cells. RT-PCR was used to follow the expression of pluripotency markers. Sorted CD15(+) , Oct4(+) and CXCR4(+) cells were cultured in an undifferentiated condition on a feeder layer of mitomycin C-inactivated C2C12. The embryoid-like bodies were differentiated into male germ cells by retinoic acid. To identify the expression of male germ specific markers, differentiated cells were analysed by means of reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence staining. RT-PCR and immunofluorescence show that bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells express pluripotency markers, Oct4, Nanog, Rex-1, SOX-2 and AP. The purified CD15(+) , Oct4(+) and CXCR4(+) formed structures like embryoid bodies when plated over a feeder layer; these bodies were alkaline phosphatase positive. When cells were induced by RA, bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) were positive for Mvh, Dazl, Piwil2, Dppa3 and Stra8, that known molecular markers of male germ cells. Thus RA can induce differentiation of mouse bone marrow-derived CD15(+) , Oct4(+) and CXCR4(+) cells into male germ cells in vitro. Negative results for the gene expression analysis of female germ cells markers, GDF9 and ZP3, confirmed this conclusion. PMID:24677291

Kashani, Iraj Ragerdi; Zarnani, Amir Hassan; Soleimani, Masoud; Abdolvahabi, Mir Abbas; Nayernia, Karim; Shirazi, Reza

2014-06-01

218

[Generation of Chicken Germ-line Chimeras by Transferring PGCs and Their Identification by AFLP.].  

PubMed

PGCs (Primordial germ cells) were isolated from the blood of 51~56 h hatching Shiqiza chicken embryos by Ficoll density gradient centrifugation. The PGCs were injected into 2.5 d hatching embryos of H breed chicken to produce germ-line chimeras. AFLP checking method was established to identify chicken germline chimeras. Eight germ-line H-S chimera embryos were identified among 20 developing H breed embryos. PMID:15985398

Hu, Xiao-Fen; Xie, Bei; Yu, Rui-Song; Huang, Qi-Zhong; Zhang, De-Fu; Huang, Lu-Sheng; Li, Zhen

2005-05-01

219

Windows for sex-specific methylation marked by DNA methyltransferase expression profiles in mouse germ cells  

Microsoft Academic Search

The acquisition of genomic methylation in the male germ line is initiated prenatally in diploid gonocytes, while DNA methylation in the female germ line is initiated postnatally in growing oocytes. We compared the temporal expression patterns of the DNA methyltransferases, DNMT1, DNMT3a, DNMT3b, and DNMT3l in the male and female germ lines. DNMT1 expression was examined by immunocytochemistry and Northerns

Sophie La Salle; Carmen Mertineit; Teruko Taketo; Peter B Moens; Timothy H Bestor; Jacquetta M Trasler

2004-01-01

220

Signaling from germ cells mediated by the rhomboid homolog stet organizes encapsulation by somatic support cells.  

PubMed

Germ cells normally differentiate in the context of encapsulating somatic cells. However, the mechanisms that set up the special relationship between germ cells and somatic support cells and the signals that mediate the crucial communications between the two cell types are poorly understood. We show that interactions between germ cells and somatic support cells in Drosophila depend on wild-type function of the stet gene. In males, stet acts in germ cells to allow their encapsulation by somatic cyst cells and is required for germ cell differentiation. In females, stet function allows inner sheath cells to enclose early germ cells correctly at the tip of the germarium. stet encodes a homolog of rhomboid, a component of the epidermal growth factor receptor signaling pathway involved in ligand activation in the signaling cell. The stet mutant phenotype suggests that stet facilitates signaling from germ cells to the epidermal growth factor receptor on somatic cells, resulting in the encapsulation of germ cells by somatic support cells. The micro-environment provided by the surrounding somatic cells may, in turn, regulate differentiation of the germ cells they enclose. PMID:12223409

Schulz, Cordula; Wood, Cricket G; Jones, D Leanne; Tazuke, Salli I; Fuller, Margaret T

2002-10-01

221

A zebrafish homologue of the chemokine receptor Cxcr4 is a germ-cell guidance receptor  

NASA Astrophysics Data System (ADS)

Germ cells preserve an individual's genetic information and transmit it to the next generation. Early in development germ cells are set aside and undergo a specialized developmental programme, a hallmark of which is the migration from their site of origin to the future gonad. In Drosophila, several factors have been identified that control germ-cell migration to their target tissues; however, the germ-cell chemoattractant or its receptor have remained unknown. Here we apply genetics and in vivo imaging to show that odysseus, a zebrafish homologue of the G-protein-coupled chemokine receptor Cxcr4, is required specifically in germ cells for their chemotaxis. odysseus mutant germ cells are able to activate the migratory programme, but fail to undergo directed migration towards their target tissue, resulting in randomly dispersed germ cells. SDF-1, the presumptive cognate ligand for Cxcr4, shows a similar loss-of-function phenotype and can recruit germ cells to ectopic sites in the embryo, thus identifying a vertebrate ligand-receptor pair guiding migratory germ cells at all stages of migration towards their target.

Knaut, Holger; Werz, Christian; Geisler, Robert; Tübingen 2000 Screen Consortium; Nüsslein-Volhard, Christiane

2003-01-01

222

A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes  

NASA Technical Reports Server (NTRS)

Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c)< 1 cm/s and v(sub f)> 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

2012-01-01

223

Contribution of donor and host mesenchyme to the transplanted tooth germs.  

PubMed

Autologous tooth germ transplantation of immature teeth is an alternative method of tooth replacement that could be used instead of dental implants in younger patients. However, it is paramount that the dental pulp remain vital and that root formation continue in the transplanted location. The goal of this study is to characterize the healing of allogenic tooth grafts in an animal model using GFP-labeled donor or host postnatal mice. In addition, the putative stem cells were labeled before transplantation with a pulse-chase paradigm. Transplanted molars formed cusps and roots and erupted into occlusion by 2 wk postoperatively. Host label-retaining cells (LRCs) were maintained in the center of pulp tissue associating with blood vessels. Dual labeling showed that a proportion of LRCs were incorporated into the odontoblast layer. Host cells, including putative dendritic cells and the endothelium, also immigrated into the pulp tissue but did not contribute to the odontoblast layer. Therefore, LRCs or putative mesenchymal stem cells are retained in the transplanted pulps. Hertwig's epithelial root sheath remains vital, and epithelial LRCs are present in the donor cervical loops. Thus, the dynamic donor-host interaction occurred in the developing transplant, suggesting that these changes affect the characteristics of the dental pulp. PMID:25376722

Nakaki, T; Saito, K; Ida-Yonemochi, H; Nakagawa, E; Kenmotsu, S; Ohshima, H

2015-01-01

224

hH-Rev107, a class II tumor suppressor gene, is expressed by post-meiotic testicular germ cells and CIS cells but not by human testicular germ cell tumors.  

PubMed Central

By systematic analysis of a human testis library, we have isolated the hH-Rev107-3 cDNA, identical to hH-Rev107-1 cDNA, which was previously described as a class II tumor suppressor gene (Husmann et al., 1998). In this study, two transcripts (1 and 0,8 kb) were detected by Northern blot in all human tissues, excepted in thymus. The strongest expression was found in testis, skeletal muscle and heart. These two mRNA are probably transcribed from only one gene that we mapped to the q12–q13 region of the chromosome 11. In human testis, hH-Rev107 gene expression was localized, by in situ hybridization, within the round spermatids. To investigate a possible role for hH-Rev107 protein in testicular malignant growth, we examined the expression of this gene in germ cell tumors. A strong hH-Rev107 gene expression was observed in normal testis as well as in samples with preinvasive carcinoma in situ but was completely absent in overt tumors, both seminomas and non-seminomas. By in situ hybridization, CIS was found hH-Rev107 positive and tumor negative. A semi-quantitative assessment of hH-Rev107 mRNA level in testicular germ cell tumors, by RT-PCR, exhibited a 9-fold decrease in the gene expression. No gross structural aberrations of hH-Rev107 gene were detected in these human primary tumors. The results suggest that down-regulation of hH-Rev107 may be associated with invasive progression of testicular germ cell tumors. PMID:11526504

Siegrist, Sylvie; Féral, Chloé; Chami, Mounia; Solhonne, Brigitte; Mattéi, Marie-Geneviève; Rajpert-De Meyts, Ewa; Guellaën, Georges; Bulle, Frédérique

2001-01-01

225

Prognosis after salvage treatment for unselected male patients with germ cell tumours.  

PubMed Central

Long-term outcome of salvage treatment was reviewed in 67 unselected male patients relapsing during or after their primary cisplatin-based chemotherapy for metastatic germ cell tumours. Seven patients underwent only surgery and/or radiotherapy as curatively intended salvage treatment. Thirty-five patients (52%) had a complete or partial response to salvage treatment, 20 (57%) of whom relapsed again. With a median follow-up of 90 months (range 3-143 months) 20 patients (30%) are alive with no evidence of disease, 15 continuously disease-free and five currently disease-free. The 5 year survival from start of salvage treatment is 37% for the group as a whole. Multivariate analysis identified age < or = 35 years, complete response to primary treatment and a relapse-free interval > 3 months as independent predictors of favourable outcome of salvage treatment. A group of patients with these good-risk factors (42%) had a 5 year survival of 72% compared with the remaining patients (58%) with a 5 year survival of only 11%. Whereas patients with good-risk features may be adequately managed by conventional salvage treatment, the remaining patients carry a very poor prognosis and require innovative and more aggressive approaches. PMID:7547217

Gerl, A.; Clemm, C.; Schmeller, N.; Hartenstein, R.; Lamerz, R.; Wilmanns, W.

1995-01-01

226

Development and evolution of the vertebrate primary mouth  

PubMed Central

The vertebrate oral region represents a key interface between outer and inner environments, and its structural and functional design is among the limiting factors for survival of its owners. Both formation of the respective oral opening (primary mouth) and establishment of the food-processing apparatus (secondary mouth) require interplay between several embryonic tissues and complex embryonic rearrangements. Although many aspects of the secondary mouth formation, including development of the jaws, teeth or taste buds, are known in considerable detail, general knowledge about primary mouth formation is regrettably low. In this paper, primary mouth formation is reviewed from a comparative point of view in order to reveal its underestimated morphogenetic diversity among, and also within, particular vertebrate clades. In general, three main developmental modes were identified. The most common is characterized by primary mouth formation via a deeply invaginated ectodermal stomodeum and subsequent rupture of the bilaminar oral membrane. However, in salamander, lungfish and also in some frog species, the mouth develops alternatively via stomodeal collar formation contributed both by the ecto- and endoderm. In ray-finned fishes, on the other hand, the mouth forms via an ectoderm wedge and later horizontal detachment of the initially compressed oral epithelia with probably a mixed germ-layer derivation. A very intriguing situation can be seen in agnathan fishes: whereas lampreys develop their primary mouth in a manner similar to the most common gnathostome pattern, hagfishes seem to undergo a unique oropharyngeal morphogenesis when compared with other vertebrates. In discussing the early formative embryonic correlates of primary mouth formation likely to be responsible for evolutionary–developmental modifications of this area, we stress an essential role of four factors: first, positioning and amount of yolk tissue; closely related to, second, endoderm formation during gastrulation, which initiates the process and constrains possible evolutionary changes within this area; third, incipient structure of the stomodeal primordium at the anterior neural plate border, where the ectoderm component of the prospective primary mouth is formed; and fourth, the prime role of Pitx genes for establishment and later morphogenesis of oral region both in vertebrates and non-vertebrate chordates. PMID:22804777

Soukup, Vladimír; Horácek, Ivan; Cerny, Robert

2013-01-01

227

Contribution of METRO pathway localized molecules to the organization of the germ cell lineage.  

PubMed

To elucidate the potential role of localized components in the specification of the germ cell lineage we analyzed the composition of the germ plasm in Xenopus laevis oocytes and early embryos with respect to the vegetally-localized RNAs. We focused on Xlsirts, Xcat2, and Xwnt11 transcripts that are localized to the vegetal cortex through a region of the mitochondrial cloud called the messenger transport organizer (METRO) that also contains the nuage or germ plasm. At the ultrastructural level Xcat2 mRNA was detected on germinal granules while Xlsirts and Xwnt11 were associated with a fibrillar network of the germ plasm in stage-1 and stage-4 oocytes. In embryos, we found that all three RNAs remained associated with the germ plasm. Vg1 mRNA, a transcript localized through the late pathway, was excluded from the germ plasm in oocytes and embryos. Addtionally, we detected the protein spectrin within 16 cell nests of germ cells, in a structure reminiscent of the Drosophila spectrosome. Spectrin was detected in the mitochondrial cloud and was found in the germ plasm during embryogenesis. These data indicate that the various RNAs found within METRO and the protein spectrin are integral components of the Xenopus germ plasm with the RNAs being associated with different subcellular structures. They also suggest that the pathway through which RNAs are localized during oogenesis may be an important factor in biasing their distribution into specific cell lineages. The presence of Xwnt11 in the germ cell lineage suggests that a wnt-directed signaling pathway may be involved in germ cell specification. differentiation or migration. PMID:9739112

Kloc, M; Larabell, C; Chan, A P; Etkin, L D

1998-07-01

228

Blimp1 is a critical determinant of the germ cell lineage in mice  

Microsoft Academic Search

Germ cell fate in mice is induced in pluripotent epiblast cells in response to signals from extraembryonic tissues. The specification of approximately 40 founder primordial germ cells and their segregation from somatic neighbours are important events in early development. We have proposed that a critical event during this specification includes repression of a somatic programme that is adopted by neighbouring

Yasuhide Ohinata; Bernhard Payer; Dónal O'Carroll; Katia Ancelin; Yukiko Ono; Mitsue Sano; Sheila C. Barton; Tetyana Obukhanych; Michel Nussenzweig; Alexander Tarakhovsky; Mitinori Saitou; M. Azim Surani

2005-01-01

229

Some relationships among germ, satellite and interstitial cells during chick gonad differentiation : A tissue culture study  

E-print Network

sex differentiation and the onset or arrest of meiosis in female or male germ cells. Wolff and his (Wolffand Haffen, 1965), thus indicating that testicular sex differentiation might be independentSome relationships among germ, satellite and interstitial cells during chick gonad differentiation

Boyer, Edmond

230

Hormonal factors and risk of ovarian germ cell cancer in young women  

Microsoft Academic Search

No previous controlled studies of ovarian germ cell tumours have been reported; however the tumour is similar to germ cell testicular cancer in terms of histology, age-specific incidence rates (i.e. highest rates in young adulthood), and secular trends of increasing incidence. The investigation was designed to determine if maternal hormonal factors which have been found to increase the risk of

AH Walker; RK Ross; RWC Haile; BE Henderson

1988-01-01

231

Stress-induced germ cell apoptosis by a p53 independent pathway in Caenorhabditis elegans  

Microsoft Academic Search

In Caenorhabditis elegans, several distinct apoptosis pathways have been characterized in the germline. The physiological pathway is though to eliminate excess germ cells during oogenesis to maintain gonad homeostasis and it is activated by unknown mechanisms. The DNA damage-induced germ cell apoptosis occurs in response to genotoxic agents and involves the proteins EGL-1 and CED-13, and the DNA damage response

L S Salinas; E Maldonado; R E Navarro

2006-01-01

232

Oil separation from foam fractions of enzymatically treated wet milled corn germ dispersions  

Technology Transfer Automated Retrieval System (TEKTRAN)

The many recent dry grind plants that convert corn to ethanol are potential sources of substantial amounts of corn oil, if an economical method of separating it can be developed. Oil was separated from corn germ by aqueous enzymatic extraction (AEE). Batches of wet- milled corn germ in water were...

233

Mixed Malignant Germ Cell Tumour of Third Ventricle with Hydrocephalus: A Rare Case with Recurrence  

PubMed Central

Malignant Germ Cell Tumours (GCTs) are rare, accounting for 3% of intracranial tumours and just like their extracranial counterparts represent a wide array of disease. Combination of Germinoma with Teratoma is very rare. Here in, we describe a case of Mixed Malignant Germ cell tumor of third ventricle with recurrence with emphasis on histopathological and radiological findings. PMID:25584231

Monappa, Vidya; Rao, Lakshmi; Kudva, Ranjini

2014-01-01

234

Digestive enzymes in the germ-free animal T. CORRING, Catherine JUSTE, C. SIMOES-NUNES  

E-print Network

Digestive enzymes in the germ-free animal T. CORRING, Catherine JUSTE, C. SIMOES-NUNES Laboratoire de Physiologie de la Nutrition, INRA, 78350 Jouy en Josas, France. Summary. The digestive physiology on digestive enzymes in the germ-free. The present paper analyzes these data. There is little information

Paris-Sud XI, Université de

235

PHYSIOLOGY, ENDOCRINOLOGY, AND REPRODUCTION Isolation of Chicken Primordial Germ Cells Using Fluorescence-Activated Cell Sorting  

Microsoft Academic Search

Presently, it is difficult to undertake germ line modification of the chicken with primordial germ cells (PGC) because it has been difficult to efficiently frac- tionate the PGC from the total somatic cell population. The objective of this study was to develop a method that allows isolation of an enriched population of viable PGC from embryonic blood and embryonic gonadal

P. E. Mozdziak; J. Angerman-Stewart; B. Rushton; S. L. Pardue; J. N. Petitte

236

From Embryonic Stem Cells to Functioning Germ Cells: Science, Clinical and Ethical Perspectives  

Microsoft Academic Search

Embryonic stem cells have been well recognized as cells having a versatile potential to differentiate into all types of cells in the body including germ cells. There are many research studies focusing on the differentiation processes and protocols to derive various types of somatic cells from embryonic stem cells. However, germ cells have unique differentiation process and developmental pathway compared

Sorapop Kiatpongsan

2007-01-01

237

Bazooka regulates microtubule organization and spatial restriction of germ plasm assembly in the Drosophila oocyte  

PubMed Central

Localization of the germ plasm to the posterior of the Drosophila oocyte is required for anteroposterior patterning and germ cell development during embryogenesis. While mechanisms governing the localization of individual germ plasm components have been elucidated, the process by which germ plasm assembly is restricted to the posterior pole is poorly understood. In this study, we identify a novel allele of baz, the Drosophila homolog of Par-3, that has allowed the analysis of baz function throughout oogenesis. We demonstrate that baz is required for spatial restriction of the germ plasm and axis patterning and we uncover multiple requirements for baz in regulating the organization of the oocyte microtubule cytoskeleton. Our results suggest that distinct cortical domains established by Par proteins polarize the oocyte through differential effects on microtubule organization. We further show that microtubule plus-end enrichment is sufficient to drive germ plasm assembly even at a distance from the oocyte cortex, suggesting that control of microtubule organization is critical not only for the localization of germ plasm components to the posterior of the oocyte but also for the restriction of germ plasm assembly to the posterior pole. PMID:20152826

Becalska, Agata N.; Gavis, Elizabeth R.

2010-01-01

238

On the analysis of neonatal hamster tooth germs with the photon microprobe at Daresbury, UK  

NASA Astrophysics Data System (ADS)

Complementary to the micro-PIXE experiments performed on hamster tooth germs to elucidate the role of fluoride during the growth, the photon microprobe at Daresbury was used to obtain information on the distribution of Zn. The germs of fluoride-administered hamsters, together with a control group, were analyzed with the micro-synchrotron radiation fluorescence method (micro-SXRF).

Tros, G. H. J.; Van Langevelde, F.; Vis, R. D.

1990-04-01

239

Pattern formation in fragmented eggs of the short germ insect Schistocerca gregaria  

Microsoft Academic Search

The effect of transverse fragmentation on the segment pattern of the short germ embryo of the locust Schistocerca gregaria has been investigated at two stages subsequent to the formation of the germ anlage. Following fragmentation both anterior and posterior partial embryos were observed, although rarely in a single egg. Anterior partial patterns usually terminated with a segment visible at the

Jane E. Mee

1986-01-01

240

Contribution of METRO pathway localized molecules to the organization of the germ cell lineage  

Microsoft Academic Search

To elucidate the potential role of localized components in the specification of the germ cell lineage we analyzed the composition of the germ plasm in Xenopus laevis oocytes and early embryos with respect to the vegetally-localized RNAs. We focused on Xlsirts, Xcat2, and Xwnt11 transcripts that are localized to the vegetal cortex through a region of the mitochondrial cloud called

Malgorzata Kloc; Carolyn Larabell; Agnes Pui-Yee Chan; Laurence D Etkin

1998-01-01

241

[Auto-transplantation of tooth germs. Discussion and presentation of 3 treated cases].  

PubMed

The authors examine the theoretical possibilities of human dental transplants: autologous, homologous and heterologous. They, then discuss-with reference to autologous transplants-an autotransplant as an alternative to prosthodontic treatment. This would apply both to traditional prosthodontic treatment and on implants or orthodontic treatment aiming at filling dental gaps. They show both general and local counterindications against this operational method the knowledge of which is necessary for an adequate selection of patients. They stress the determining factors for a successful autotransplant: 1) particular care with the choice of the germ to be transplanted taking into account its morphology and the stage of root development; 2) adequate surgical preparation of the receiving site in relation to the size of the germ to be transplanted; 3) suitable surgical technique entailing a particular care in the manipulation of soft and hard tissues and of the germ and appropriate conditions of sterilization; 4) use of appropriate retention means to ensure stability of the transplanted germ so as to favour cellular proliferation and reduce osteoclastic activity; 5) reduction of occlusal pressure on the transplanted germ. The authors describe for example's sake 3 out of 32 cases treated with the documentation of the achieved long-term success. They also analyse the possible causes of failure of such operational method (careless manipulation of the germ, incorrect surgical technique, removal of the germ in a too early stage of its development, too long exposure of the germ outside the oral cavity, poor oral hygiene, caries, periodontal disease, occlusal trauma. PMID:9297076

Massei, G; Cardesi, E

1997-01-01

242

New insights into the pathology and molecular biology of human germ cell tumors  

Microsoft Academic Search

The group of human germ cell tumors (GCTs) is heterogeneous, and comprises neoplasms found at different anatomical locations. They are of interest not only for aspects of their tumor biology, but also from the point of view of developmental biology. GCTs show significant similarities to early germ cell development, most likely related to their cell of origin. Comparative analysis of

Friedemann Honecker; J. Wolter Oosterhuis; Frank Mayer; JörgThomas Hartmann; Carsten Bokemeyer; Leendert H. J. Looijenga

2004-01-01

243

Survey and Detection of Endophytic Fungi in Lolium Germ Plasm by Direct Staining and Aphid Assays  

Microsoft Academic Search

Wilson, A. D., Clement, S. L., and Kaiser, W. J. 1991. Survey and detection of endophytic fungi in Lolium germ plasm by direct staining and aphid assays. Plant Dis. 75:169-173. Clavicipitaceous anamorphic endophytes were detected in 28 of 85 accessions from five of eight species in a collection of Lolium germ plasm. Comparative descriptions of endophytic mycelium in seeds of

A. DAN WILSON; STEPHEN L. CLEMENT; WALTER J. KAISER

244

Immature germ cells in semen – correlation with total sperm count and sperm motility  

PubMed Central

Background: Current data regarding infertility suggests that male factor contributes up to 30% of the total cases of infertility. Semen analysis reveals the presence of spermatozoa as well as a number of non-sperm cells, presently being mentioned in routine semen report as “round cells” without further differentiating them into leucocytes or immature germ cells. Aim: The aim of this work was to study a simple, cost-effective, and convenient method for differentiating the round cells in semen into immature germ cells and leucocytes and correlating them with total sperm counts and motility. Materials and Methods: Semen samples from 120 males, who had come for investigation for infertility, were collected, semen parameters recorded, and stained smears studied for different round cells. Statistical analysis of the data was done to correlate total sperm counts and sperm motility with the occurrence of immature germ cells and leucocytes. The average shedding of immature germ cells in different groups with normal and low sperm counts was compared. The clinical significance of “round cells” in semen and their differentiation into leucocytes and immature germ cells are discussed. Conclusions: Round cells in semen can be differentiated into immature germ cells and leucocytes using simple staining methods. The differential counts mentioned in a semen report give valuable and clinically relevant information. In this study, we observed a negative correlation between total count and immature germ cells, as well as sperm motility and shedding of immature germ cells. The latter was statistically significant with a P value 0.000. PMID:24130411

Patil, Priya S.; Humbarwadi, Rajendra S.; Patil, Ashalata D.; Gune, Anita R.

2013-01-01

245

The Y Deletion gr\\/gr and Susceptibility to Testicular Germ Cell Tumor  

Microsoft Academic Search

Testicular germ cell tumor (TGCT) is the most common cancer in young men. Despite a considerable familial component to TGCT risk, no genetic change that confers increased risk has been substantiated to date. The human Y chromosome carries a number of genes specifically involved in male germ cell development, and deletion of the AZFc region at Yq11 is the most

Katherine L. Nathanson; Peter A. Kanetsky; Rachel Hawes; David J. Vaughn; Richard Letrero; Kathy Tucker; Michael Friedlander; Kelly-Anne Phillips; David Hogg; Michael A. S. Jewett; Radka Lohynska; Gedske Daugaard; Stéphane Richard; Agnès Chompret; Catherine Bonaïti-Pellié; Axel Heidenreich; Edith Olah; Lajos Geczi; Istvan Bodrogi; Wilma J. Ormiston; Peter A. Daly; J. Wolter Oosterhuis; Ad J. M. Gillis; Leendert H. J. Looijenga; Parry Guilford; Sophie D. Fosså; Ketil Heimdal; Sergei A. Tjulandin; Ludmila Liubchenko; Hans Stoll; Walter Weber; Matthew Rudd; Robert Huddart; Gillian P. Crockford; David Forman; D. Timothy Oliver; Lawrence Einhorn; Barbara L. Weber; Joan Kramer; Mary McMaster; Mark H. Greene; Malcolm Pike; Victoria Cortessis; Chu Chen; Stephen M. Schwartz; D. Timothy Bishop; Douglas F. Easton; Michael R. Stratton; Elizabeth A. Rapley

2005-01-01

246

Germ-Line Gene Modification and Disease Prevention: Some Medical and Ethical Perspectives  

Microsoft Academic Search

There has been considerable debate about the ethics of human germ-line gene modification. As a result of recent advances in the micromanipulation of embryos and the laboratory development of transgenic mice, a lively discussion has begun concerning both the technical feasibility and the ethical acceptability of human germ-line modification for the prevention of serious disease. This article summarizes some of

Nelson A. Wivel; Leroy Walters

1993-01-01

247

Derivation of embryonic germ cells and male gametes from embryonic stem cells  

Microsoft Academic Search

Egg and sperm cells (gametes) of the mouse are derived from a founder population of primordial germ cells that are set aside early in embryogenesis. Primordial germ cells arise from the proximal epiblast, a region of the early mouse embryo that also contributes to the first blood lineages of the embryonic yolk sac. Embryonic stem cells differentiate in vitro into

Niels Geijsen; Melissa Horoschak; Kitai Kim; Joost Gribnau; Kevin Eggan; George Q. Daley

2004-01-01

248

Properties of a terminal deoxyribonucleotidyltransferase isolated from wheat germ.  

PubMed Central

An enzyme able to catalyse the polymerization of deoxyribonucleotides in a template-independent manner was isolated from dry wheat germ. This activity is associated with a soluble protein which is homogeneous with respect to the molecular weight (approx. 500000) and, under denaturing conditions, dissociates into product of two size classes, 67000 and 45000 daltons respectively. The enzyme-catalysed polymerization can be primed by oligo- as well as poly-deoxyribonucleotides, and is highly efficient (234 nmol/h per mg of finally purified protein) when only one of the four deoxyribonucleoside 5'-triphosphates is present in the incubation mixture. An extension of the 3'-hydroxy termini of polydeoxyribonucleotide chains for approx. 40 nucleotide residues was achieved when non-denatured DNA and [3H]dTTP were used as the primer and substrate respectively. It is concluded that the enzyme isolated from wheat germ shares catalytic properties with the terminal deoxynucleotidyltransferase of mammalian thymus. Unlike that transferase, however, the plant enzyme prefers non-denatured to single-stranded DNA as primer and requires both Mg2+ and Mn2+ ions for maximal activity. Images Fig. 3. PMID:7470090

Brodniewicz-Proba, T; Buchowicz, J

1980-01-01

249

Maintenance of mouse male germ line stem cells in vitro.  

PubMed

The proliferation and differentiation of a stem cell are regulated intrinsically by the stem cell and extrinsically by the stem cell niche. Elucidation of regulatory mechanisms of spermatogonial stem cells (SSCs), the stem cell of the postnatal male germ line, would be facilitated by in vitro studies that provide a defined microenvironment reconstituted ex vivo. We analyzed the effect of in vitro environment on the maintenance of adult and immature SSCs in a 7-day culture system. Although the number of adult and immature SSCs decreased in a time-dependent manner, nearly one in four stem cells (24%) could be maintained in vitro for 7 days. Stem cell maintenance was enhanced by coculture with OP9 bone marrow stroma or L fibroblast cell lines, addition of glial cell line-derived neurotrophic factor, or utilization of specific culture medium. In contrast, coculture with TM4 or SF7 Sertoli cell lines and addition of activin A or bone morphogenetic protein 4 (BMP4) reduced stem cell maintenance in vitro. Only 4% of the stem cells remained when cultured with TM4 cells or activin A, and 6% remained when cultured with SF7 cells or BMP4. These results lead to the hypothesis that suppression of germ cell differentiation improves in vitro maintenance of SSCs by interrupting the unidirectional cascade of spermatogenesis and blocking stem cell differentiation. PMID:12606373

Nagano, Makoto; Ryu, Buom-Yong; Brinster, Clayton J; Avarbock, Mary R; Brinster, Ralph L

2003-06-01

250

Germ line determinants are not localized early in sea urchin development, but do accumulate in the small micromere lineage  

Microsoft Academic Search

Two distinct modes of germ line determination are used throughout the animal kingdom: conditional—an inductive mechanism, and autonomous—an inheritance of maternal factors in early development. This study identifies homologs of germ line determinants in the sea urchin Strongylocentrotus purpuratus to examine its mechanism of germ line determination. A list of conserved germ-line associated genes from diverse organisms was assembled to

Celina E. Juliano; Ekaterina Voronina; Christie Stack; Maryanna Aldrich; Andrew R. Cameron; Gary M. Wessel

2006-01-01

251

Overexpression of peroxisomal testis-specific 1 protein induces germ cell apoptosis and leads to infertility in male mice  

PubMed Central

?Peroxisomal testis-specific 1 gene (Pxt1) is the only male germ cell–specific gene that encodes a peroxisomal protein known to date. To elucidate the role of Pxt1 in spermatogenesis, we generated transgenic mice expressing a c-MYC-PXT1 fusion protein under the control of the PGK2 promoter. Overexpression of Pxt1 resulted in induction of male germ cells’ apoptosis mainly in primary spermatocytes, finally leading to male infertility. This prompted us to analyze the proapoptotic character of mouse PXT1, which harbors a BH3-like domain in the N-terminal part. In different cell lines, the overexpression of PXT1 also resulted in a dramatic increase of apoptosis, whereas the deletion of the BH3-like domain significantly reduced cell death events, thereby confirming that the domain is functional and essential for the proapoptotic activity of PXT1. Moreover, we demonstrated that PXT1 interacts with apoptosis regulator BAT3, which, if overexpressed, can protect cells from the PXT1-induced apoptosis. The PXT1-BAT3 association leads to PXT1 relocation from the cytoplasm to the nucleus. In summary, we demonstrated that PXT1 induces apoptosis via the BH3-like domain and that this process is inhibited by BAT3. PMID:21460186

Kaczmarek, Karina; Studencka, Maja; Meinhardt, Andreas; Wieczerzak, Krzysztof; Thoms, Sven; Engel, Wolfgang; Grzmil, Pawel

2011-01-01

252

Focus Issue: From Egg to Egg--Cell Signaling in Germ Cells  

NSDL National Science Digital Library

In this Focus Issue of Science’s STKE, which complements the Science Special Issue on germ cells, we take a closer look at cell signaling in germ cells. STKE highlights the migration of germ cells with an article that describes the different mechanisms controlling primordial germ cell movement and survival in mice and flies. Another article describes a mechanism for mediating plant self-incompatibility through control of the pollen tube, to prevent inappropriate delivery of incompatible sperm to the ovule. A common feature found in each of the organisms discussed, be they animal, insect or plant, is that signals from the surrounding tissues control survival and migration of the germ cells or resulting gametes.

Elizabeth M. Adler (American Association for the Advancement of Science; Science's STKE REV)

2007-04-24

253

Germ cell pluripotency, premature differentiation and susceptibility to testicular teratomas in mice  

PubMed Central

Testicular teratomas result from anomalies in germ cell development during embryogenesis. In the 129 family of inbred strains of mice, teratomas initiate around embryonic day (E) 13.5 during the same developmental period in which female germ cells initiate meiosis and male germ cells enter mitotic arrest. Here, we report that three germ cell developmental abnormalities, namely continued proliferation, retention of pluripotency, and premature induction of differentiation, associate with teratoma susceptibility. Using mouse strains with low versus high teratoma incidence (129 versus 129-Chr19MOLF/Ei), and resistant to teratoma formation (FVB), we found that germ cell proliferation and expression of the pluripotency factor Nanog at a specific time point, E15.5, were directly related with increased tumor risk. Additionally, we discovered that genes expressed in pre-meiotic embryonic female and adult male germ cells, including cyclin D1 (Ccnd1) and stimulated by retinoic acid 8 (Stra8), were prematurely expressed in teratoma-susceptible germ cells and, in rare instances, induced entry into meiosis. As with Nanog, expression of differentiation-associated factors at a specific time point, E15.5, increased with tumor risk. Furthermore, Nanog and Ccnd1, genes with known roles in testicular cancer risk and tumorigenesis, respectively, were co-expressed in teratoma-susceptible germ cells and tumor stem cells, suggesting that retention of pluripotency and premature germ cell differentiation both contribute to tumorigenesis. Importantly, Stra8-deficient mice had an 88% decrease in teratoma incidence, providing direct evidence that premature initiation of the meiotic program contributes to tumorigenesis. These results show that deregulation of the mitotic-meiotic switch in XY germ cells contributes to teratoma initiation. PMID:22438569

Heaney, Jason D.; Anderson, Ericka L.; Michelson, Megan V.; Zechel, Jennifer L.; Conrad, Patricia A.; Page, David C.; Nadeau, Joseph H.

2012-01-01

254

Oil separation from wet milled corn germ dispersions as part of aqueous oil extraction and aqueous enzymatic oil extraction  

Technology Transfer Automated Retrieval System (TEKTRAN)

Oil was obtained from corn germ by aqueous extraction (AE). 100 g batches of germ were mixed with a buffer solution to a mass concentration of 5 to 20% germ, preheated under 2 atm. pressure (120oC), milled in a blender and then churned in an incubator/shaker to coalesce and float oil droplets. The ...

255

Improved solubility, emulsification, and water retention of wet-milled corn germ protein recovered by ultrafiltration-diafiltration  

Technology Transfer Automated Retrieval System (TEKTRAN)

This study evaluated ultrafiltration-diafiltration (UFDF) as a means to improve the extractability of wet-milled corn germ protein and determined its effects on the functional properties of the recovered protein product. Wet germ (WG) and finished germ (FG) proteins (Pr) were extracted by using 0.1M...

256

Removal and isolation of germ-rich fractions from hull-less barley using a fitzpatrick comminuting mill  

Technology Transfer Automated Retrieval System (TEKTRAN)

A process was developed to produce a germ-enriched fraction from hull-less barley using a Fitzpatrick Comminuting Mill followed by sieving. Hulled and hull-less barleys contain 1.5-2.5% oil and, like wheat kernels which contain wheat germ oil, much of the oil in barley kernels is in the germ fracti...

257

Addition of Wheat Germ Oil to a Liquid Larval Diet for Rearing Improved Quality Oriental Fruit Flies (Diptera: Tephritidae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat germ oil was added into a low waste larval liquid diet for rearing Bactrocera dorsalis (Hendel) to optimize the fruit fly performance. Various concentrations of 0.04, 0.07, 0.15, 0.30, and 0.66 % of wheat germ oil were evaluated. Results showed that the addition of wheat germ oil did not affec...

258

The Ter Mutation In The Dead End Gene Causes Germ Cell Loss And Testicular Germ Cell Tumours  

SciTech Connect

In mice, the Ter mutation causes primordial germ cell (PGC) loss in all genetic backgrounds1. Ter is also a potent modifier of spontaneous testicular germ cell tumour (TGCT) susceptibility in the 129 family of inbred strains, and markedly increases TGCT incidence in 129-Ter/Ter males2 4. In 129-Ter/Ter mice, some of the remaining PGCs transform into undifferentiated pluripotent embryonal carcinoma cells2 6, and after birth differentiate into various cells and tissues that compose TGCTs. Here, we report the positional cloning of Ter, revealing a point mutation that introduces a termination codon in the mouse orthologue (Dnd1) of the zebrafish dead end (dnd) gene. PGC deficiency is corrected both with bacterial artificial chromosomes that contain Dnd1 and with a Dnd1-encoding transgene. Dnd1 is expressed in fetal gonads during the critical period when TGCTs originate. DND1 has an RNA recognition motif and is most similar to the apobec complementation factor, a component of the cytidine t o uridine RNA-editing complex. These results suggest that Ter may adversely affect essential aspects of RNA biology during PGC development. DND1 is the first protein known to have an RNA recognition motif directly implicated as a heritable cause of spontaneous tumorigenesis. TGCT development in the 129-Ter mouse strain models paediatric TGCT in humans. This work will have important implications for our understanding of the genetic control of TGCT pathogenesis and PGC biology.

Youngren, Kirsten K.; Coveney, Douglas; Peng, Xiaoning; Bhattacharya, Chitralekha; Schmidt, Laura S.; Nickerson, Michael L.; Lamb, Bruce T.; Deng Jian Min; Behringer, Richard R.; Capel, Blanche; Rubin, Edward M.; Nadeau, Joseph H.; Matin, Angabin

2005-01-01

259

X-ray micro-analysis of the mineralization patterns in developing enamel in hamster tooth germs exposed to fluoride in vitro during the secretory phase of amelogenesis  

SciTech Connect

The developing enamel from three-day-old hamster first maxillary (M1) molar tooth germs exposed to fluoride (F-) in vitro was analyzed for its mineral content by means of the energy-dispersive x-ray microanalysis technique. The aim of this study was to obtain semi-quantitative data on the F(-)-induced hypermineralization patterns in the enamel and to confirm that the increase in electron density observed in micrographs of F(-)-treated enamel is indeed due to an increase in mineral content in the fluorotic enamel. The tooth germs were explanted during the early stages of secretory amelogenesis and initially cultured for 24 hr in the presence of 10 ppm F- in the culture medium. The germs were then cultured for another 24 hr without F-. In order to compare the ultrastructural results directly with the microprobe data, we used the same specimens for both investigations. The net calcium counts (measurement minus background counts) in the analyses were used as a measure of the mineral content in the enamel. The aprismatic pre-exposure enamel, deposited in vivo before the onset of culture, was the most hypermineralized region in the fluorotic enamel, i.e., it contained the highest amount of calcium measured. The degree of the F(-)-induced hypermineralization gradually decreased (but was not abolished) in the more mature regions of the enamel. The unmineralized enamel matrix secreted during the initial F- treatment in vitro mineralized during the subsequent culture without F-. The calcium content in this enamel layer was in the same order of magnitude as that recorded for the newly deposited enamel in control tooth germs cultured without F-.

Lyaruu, D.M.; Blijleven, N.; Hoeben-Schornagel, K.; Bronckers, A.L.; Woeltgens, J.H.

1989-09-01

260

Deconjugation of bilirubin conjugates and urobilin formation by conventionalized germ-free rats.  

PubMed

The amounts of conjugated bilirubin and urobilins/urobilinogen were determined semiquantitatively in faeces of germ-free (GF) rats during GF condition and after conventionalization by oral administration of faeces suspension from conventional (CONV) rats. The amount of bilirubin conjugates, detected as their ethyl anthranilate azopigments, decreased rapidly 1 day after conventionalization. Thin-layer chromatography analysis of the corresponding faecal azopigment preparations showed that some azopigments started to disappear a few days after the conventionalization, indicating that their corresponding bilirubin conjugates were deconjugated by the bacteria in the intestine. On day 21 after conventionalization, only two azopigments were detected, namely the unconjugated and glucuronic acid conjugated dipyrroles of bilirubin, respectively, thus indicating the presence of only one bilirubin conjugate, the monoglucuronide. After 69 days no azopigments could be detected, indicating the total absence of conjugated bilirubin in these faeces samples. No urobilins were detected in faeces of the rats during their GF state, but these metabolites appeared in faeces one day after conventionalization and increased during a few days to a CONV level. PMID:6484492

Saxerholt, H; Midtvedt, T; Gustafsson, B E

1984-10-01

261

The story of a largely unknown evolution - Germ theory hoax.  

PubMed

The Piltdown Man debacle provides us with the most infamous forgery in science. However, another equally intriguing story exists concerning a document by a Bostonian called George Sleeper, which purported to be a pre-Darwin-Wallace anticipation of evolution and an equally convincing account of the germ theory published before Louis Pasteur's famous studies on this subject. The story involves two giants in the world of evolutionary theory, Alfred Russel Wallace and E.B. Poulton. While Wallace was convinced that the Sleeper document was genuine, Poulton's detailed investigations showed that it was a fake and a hoax. Despite this conclusion, doubts still exist about the authenticity of the Sleeper document. PMID:23961141

Wainwright, Milton; Alharbi, Sulaiman Ali

2011-10-01

262

The story of a largely unknown evolution – Germ theory hoax  

PubMed Central

The Piltdown Man debacle provides us with the most infamous forgery in science. However, another equally intriguing story exists concerning a document by a Bostonian called George Sleeper, which purported to be a pre-Darwin–Wallace anticipation of evolution and an equally convincing account of the germ theory published before Louis Pasteur’s famous studies on this subject. The story involves two giants in the world of evolutionary theory, Alfred Russel Wallace and E.B. Poulton. While Wallace was convinced that the Sleeper document was genuine, Poulton’s detailed investigations showed that it was a fake and a hoax. Despite this conclusion, doubts still exist about the authenticity of the Sleeper document. PMID:23961141

Wainwright, Milton; Alharbi, Sulaiman Ali

2011-01-01

263

The fog-3 gene and regulation of cell fate in the germ line of Caenorhabditis elegans  

SciTech Connect

In the nematode Caenorhabditis elegans, germ cells normally adopt one of three fates: mitosis, spermatogenesis or oogenesis. We have identified and characterized the gene fog-3, which is required for germ cells to differentiate as sperm rather than as oocytes. Analysis of double mutants suggests that fog-3 is absolutely required for spermatogenesis and acts at the end of the regulatory hierarchy controlling sex determination for the germ line. By contrast, mutations in fog-3 do not alter the sexual identity of other tissues. We also have characterized the null phenotype of fog-1, another gene required for spermatogenesis; we demonstrate that it too controls the sexual identity of germ cells but not of other tissues. Finally, we have studied the same interaction of these two fog genes with gld-1, a gene required for germ cells to undergo oogenesis rather than mitosis. On the basis of these results, we propose that germ-cell fate might be controlled by a set of inhibitory interactions among genes that specify one of three fates: mitosis, spermatogenesis or oogenesis. Such a regulatory network would link the adoption of one germ-cell fate to the suppression of the other two. 68 refs., 7 figs., 6 tabs.

Ellis, R.; Kimble, J. [Univ. of Wisconsin, Madison, WI (United States)

1995-02-01

264

Pediatric Germ Cell Tumors; A 10-year Experience  

PubMed Central

Objective: The aim of this study was to evaluate the outcome of germ cell tumors in patients admitted to our center during a ten year period. Methods: In a retrospective descriptive study, patients with the pathological diagnosis of germ cell tumor (GCT) were included. All records were evaluated and patients followed by personal visit in clinic or phone call. Data regarding age, sex, tumor site, bio-chemical assay, pathology, treatment and outcomes were gathered. For qualitative variables we computed frequency and percentage and for quantitative variables, mean and standard deviation. Survival analysis was performed using Kaplan-Meier. All statistical analyses were performed by SPSS version16.0. Findings : Forty four patients consisted of 32 girls (72.7%) and 12 boys (27.3%). Their median age was 23 months. The most common pathological tumor types were 18 (40.9%) mature teratomas and 14 (31.8%) yolk sac tumors. Extra gonadal tumors were more prevalent (32 cases) and consisted of 21 (47.7%) sacrcoccygeal, 7 (15.9%) retroperitoneal, 2 (4.4%) mediastinal and 2 (4.4%) cervical tumors. In gonadal tumors 9 patients had ovarian and 3 patients testicular involvement. Staging at the time of diagnosis revealed stage one in 23 (52.3%) cases. All patients were treated surgically and the most common procedure was total resection in 41 (93.2%) patients. Fifteen (34.1%) patients received chemotherapy. In follow-up 31 (77.5%) patients were in complete remission, 9 (22.5%) had died, and 4 cases did not appear to follow-up visits. The median survival was 16 months (IQR 4-49 months). The highest mortality rate was found in patients with yolk sac tumors (8 of 13 cases). Conclusion: The patients with extra-gonadal GCT and a high AFP level have the worst prognosis and lower survival rate. Combination of surgery and chemotherapy can lead to a better prognosis. PMID:25755868

Khaleghnejad-Tabari, Ahmad; Mirshemirani, Alireza; Rouzrokh, Mohsen; Mohajerzadeh, Leily; Khaleghnejad-Tabari, Nasibeh; Hasas-Yeganeh, Shaghayegh

2014-01-01

265

Isolation and Enrichment of Mouse Female Germ Line Stem Cells  

PubMed Central

Objective The existence of female germ-line stem cells (FGSCs) has been the subject of a wide range of recent studies. Successful isolation and culture of FGSCs could facilitate studies on regenerative medicine and infertility treatments in the near future. Our aim in the present study was evaluation of the most commonly used techniques in enrichment of FGSCs and in establishment of the best procedure. Materials and Methods In this experimental study, after digesting neonate ovary from C57Bl/6 mice, we performed 2 different isolation experiments: magnetic activated cell sorting (MACS) and pre-plating. MACS was applied using two different antibodies against mouse vasa homolog (MVH) and stage-specific embryonic antigen-1 (SSEA1) markers. After the cells were passaged and proliferated in vitro, colony-forming cells were characterized using reverse transcription-polymerase chain reaction (RT-PCR) (for analysis of expression of Oct4, Nanog, C-kit, Fragilis, Mvh, Dazl, Scp3 and Zp3), alkaline phosphatase (AP) activity test and immunocytochemistry. Results Data showed that colonies can be seen more frequently in pre-plating technique than that in MACS. Using the SSEA1 antibody with MACS, 1.98 ± 0.49% (Mean ± SDV) positive cells were yield as compared to the total cells sorted. The colonies formed after pre-plating expressed pluripotency and germ stem cell markers (Oct4, Nanog, C-kit, Fragilis, Mvh and Dazl) whereas did not express Zp3 and Scp3 at the mRNA level. Immunocytochemistry in these colonies further confirmed the presence of OCT4 and MVH proteins, and AP activity measured by AP-kit showed positive reaction. Conclusion We established a simple and an efficient pre-plating technique to culture and to enrich FGSCs from neonatal mouse ovaries. PMID:25685731

Khosravi-Farsani, Somayeh; Amidi, Fardin; Habibi Roudkenar, Mehryar; Sobhani, Aligholi

2015-01-01

266

Long-term follow-up of residual masses after chemotherapy in patients with non-seminomatous germ cell tumours  

PubMed Central

This retrospective study was undertaken to determine the outcome of patients with non-seminomatous germ cell tumour who achieved a serological complete response but who had residual radiologic abnormalities upon completion of primary platinum-based chemotherapy. This was an analysis of 76 consecutive patients treated at Mount Vernon Hospital between 1983 and 1997. The patients were placed into two groups based upon whether they had surgical resection (surgery group, 48 patients) or observation (observation group, 28 patients) of residual radiologic masses on completion of initial chemotherapy (to enter the surgery group, complete surgical resection must have been achieved). The primary end-points were progression-free and overall survival. The percentage of patients alive with median follow-up 66 months was 90% for the surgery group and 80% for the observation group (P= 0.53, not significant). The percentage of patients continuously disease-free was 70% in the surgery group and 80% in the observation group (P= 0.31, not significant). In the small sub-group of patients with differentiated teratoma (TD) in the primary lesion who were observed, there was no excess risk of relapse or death. Patients who achieve a serological complete response after primary chemotherapy, but are left with ? 2?cm radiological masses that are not cystic and have responded, can be safely observed with diligent follow-up. © 2000 Cancer ResearchCampaign PMID:11044349

Napier, M P; Naraghi, A; Christmas, T J; Rustin, G J S

2000-01-01

267

Differentiation of Human Embryonic Stem Cells into Embryoid Bodies Comprising the Three Embryonic Germ Layers  

Microsoft Academic Search

Background: Embryonic stem (ES) cells are lines of cells that are isolated from blastocysts. The murine ES cells were demonstrated to be true pluripotent cells as they differentiate into all embry- onic lineages. Yet, in vitro differentiation of rhesus ES cells was somewhat inconsistent and disorga- nized. The recent isolation of human ES cells calls for exploring their pluripotential nature.

Joseph Itskovitz-Eldor

2000-01-01

268

Meiotic Errors Activate Checkpoints that Improve Gamete Quality without Triggering Apoptosis in Male Germ Cells  

PubMed Central

Summary Background Meiotic checkpoints ensure the production of gametes with the correct complement and integrity of DNA; in metazoans these pathways sense errors and transduce signals to trigger apoptosis to eliminate damaged germ cells. The extent to which checkpoints monitor and safeguard the genome differs between sexes and may contribute to the high frequency of human female meiotic errors. In the C. elegans female germ line, DNA damage, chromosome asynapsis and/or unrepaired meiotic double strand breaks (DSBs) activate checkpoints that induce apoptosis; conversely, male germ cells do not undergo apoptosis. Results Here we show that the recombination checkpoint is in fact activated in male germ cells despite the lack of apoptosis. The 9-1-1 complex and phosphatidylinositol 3-kinase-related protein kinase ATR, sensors of DNA damage, are recruited to chromatin in the presence of unrepaired meiotic DSBs in both female and male germ lines. Furthermore, checkpoint kinase CHK-1 is phosphorylated and p53 ortholog CEP-1 induces expression of BH3-only pro-apoptotic proteins in germ lines of both sexes under activating conditions. The core cell death machinery is expressed in female and male germ lines; however, CED-3 caspase is not activated in the male germ line. Although apoptosis is not triggered, checkpoint activation in males has functional consequences for gamete quality, as there is reduced viability of progeny sired by males with a checkpoint-activating defect in the absence of checkpoint function. Conclusions We propose that the recombination checkpoint functions in male germ cells to promote repair of meiotic recombination intermediates, thereby improving the fidelity of chromosome transmission in the absence of apoptosis. PMID:20970339

Jaramillo-Lambert, Aimee; Harigaya, Yuriko; Vitt, Jeffrey; Villeneuve, Anne; Engebrecht, JoAnne

2010-01-01

269

Multimodality therapy for CNS mixed malignant germ cell tumors (MMGCT): results of a phase II multi-institutional study.  

PubMed

In order to improve outcomes for CNS mixed malignant germ cell tumors (MMGCT) we sought to increase complete responses (CR) to initial therapy, through intensifying neoadjuvant chemotherapy (CHT1) with added ifosfamide, encouraging second-look surgery, and administering dose-intensive, stem cell-supported chemotherapy (CHT2) to patients with residual tumor, all prior to radiation therapy (RT). Diagnosis was confirmed by biopsy or elevated germ cell tumor markers. After tumor staging was completed, patients received four cycles of chemotherapy (cisplatin, etoposide and ifosfamide, "CHT1"). In patients with primary; for disseminated tumors or < CR before RT, craniospinal irradiation (CSI) plus boosts to primary site(s) and bulky metastases. 26 patients (19 M0, 7 M+) were enrolled. The diagnosis was established by histology (20) or elevated markers (6). Objective responses to CHT1 were complete in 12/22 patients with evaluable disease and partial in 10; 8 additional tumors were rendered CR prior to RT (5 surgical CRs: 3 initial, 2 second-look; 3 CRs to CHT2). Thus, 20/26 patients (77%) were free of disease (CR) prior to RT. Six-year relapse-free survival was 63 ± 10%; overall survival was 68 ± 9%. Of 16 M0 patients who received only WVRT, four relapsed in the spine, outside the radiation field. The relatively high frequency (25%) of relapse outside the initial RT volume highlights the limitations of initial staging criteria and the curative potential of conventional and high dose chemotherapy. CSI remains the standard of care for CNS MMGCT, even for patients with localized disease. PMID:24700239

Robertson, Patricia L; Jakacki, Regina; Hukin, Juliette; Siffert, Joao; Allen, Jeffrey C

2014-05-01

270

Germ Tube Mediated Invasion of Batrachochytrium dendrobatidis in Amphibian Skin Is Host Dependent  

PubMed Central

Batrachochytrium dendrobatidis (Bd) is the causative agent of chytridiomycosis, a fungal skin disease in amphibians and driver of worldwide amphibian declines. We focussed on the early stages of infection by Bd in 3 amphibian species with a differential susceptibility to chytridiomycosis. Skin explants of Alytes muletensis, Litoria caerulea and Xenopus leavis were exposed to Bd in an Ussing chamber for 3 to 5 days. Early interactions of Bd with amphibian skin were observed using light microscopy and transmission electron microscopy. To validate the observations in vitro, comparison was made with skin from experimentally infected frogs. Additional in vitro experiments were performed to elucidate the process of intracellular colonization in L. caerulea. Early interactions of Bd with amphibian skin are: attachment of zoospores to host skin, zoospore germination, germ tube development, penetration into skin cells, invasive growth in the host skin, resulting in the loss of host cell cytoplasm. Inoculation of A. muletensis and L. caerulea skin was followed within 24 h by endobiotic development, with sporangia located intracellularly in the skin. Evidence is provided of how intracellular colonization is established and how colonization by Bd proceeds to deeper skin layers. Older thalli develop rhizoid-like structures that spread to deeper skin layers, form a swelling inside the host cell to finally give rise to a new thallus. In X. laevis, interaction of Bd with skin was limited to an epibiotic state, with sporangia developing upon the skin. Only the superficial epidermis was affected. Epidermal cells seemed to be used as a nutrient source without development of intracellular thalli. The in vitro data agreed with the results obtained after experimental infection of the studied frog species. These data suggest that the colonization strategy of B. dendrobatidis is host dependent, with the extent of colonization most likely determined by inherent characteristics of the host epidermis. PMID:22911798

Van Rooij, Pascale; Martel, An; D'Herde, Katharina; Brutyn, Melanie; Croubels, Siska; Ducatelle, Richard; Haesebrouck, Freddy; Pasmans, Frank

2012-01-01

271

Severe acute tumor lysis syndrome in patients with germ-cell tumors  

PubMed Central

Germ-cell tumors are a high-proliferative type of cancer that may evolve to significant bulky disease. Tumor lysis syndrome is rarely reported in this setting. The reports of three patients with germ-cell tumors who developed severe acute tumor lysis syndrome following the start of their anticancer therapy are presented. All patients developed renal dysfunction and multiorgan failure. Patients with extensive germ-cell tumors should be kept on close clinical and laboratory monitoring. Physicians should be aware of this uncommon but severe complication and consider early admission to the intensive care unit for the institution of measures to prevent acute renal failure. PMID:19468517

Feres, Guilherme Alvarenga; Salluh, Jorge Ibrain Figueira; Ferreira, Carlos Gil; Soares, Marcio

2008-01-01

272

SOX17 is a Critical Specifier of Human Primordial Germ Cell Fate  

E-print Network

cell biology (Looijenga et al., 2014; Schafer et al., 2011). CD38: ACoreMarker of HumanGerm-Cell-Related Cells and Initiation of the Epigenetic Program CD38, an established cell-surface glycoprotein on leukocytes, is a prognostic marker of leukemia... are among the key regulators of germ cell fate. SOX17 and BLIMP1 are ression of early human germ cell lineage. CD38, a cell-surface glycoprotein, is 7 or BLIMP1 abrogates hPGCLC specification. Cell 160, 253–268, January 15, 2015 ª2015 The Authors 265...

Irie, Naoko; Weinberger, Leehee; Tang, Walfred W. C.; Kobayashi, Toshihiro; Viukov, Sergey; Manor, Yair S.; Dietmann, Sabine; Hanna, Jacob H.; Surani, M. Azim

2014-12-24

273

Identification and Genetic Analysis of Wunen, a Gene Guiding Drosophila Melanogaster Germ Cell Migration  

PubMed Central

We describe a novel genetic locus, wunen (wun), required for guidance of germ cell migration in early Drosophila development. Loss of wun function does not abolish movement but disrupts the orientation of the motion causing the germ cells to disperse even though their normal target, the somatic gonad, is well formed. We demonstrate that the product of this gene enables a signal to pass from the soma to the germ line and propose that the function of this signal is to selectively stabilize certain cytoplasmic extensions resulting in oriented movement. To characterize this guidance factor, we have mapped wun to within 100 kb of cloned DNA. PMID:8807296

Zhang, N.; Zhang, J.; Cheng, Y.; Howard, K.

1996-01-01

274

Malignant germ cell tumours of childhood: new associations of genomic imbalance  

PubMed Central

Malignant germ cell tumours (MGCTs) of childhood are a rare group of neoplasms that comprise many histological subtypes and arise at numerous different sites. Genomic imbalances have been described in these tumours but, largely because of the paucity of cases reported in the literature, it is unclear how they relate to abnormalities in adult MGCTs and impact on potential systems for classifying GCTs. We have used metaphase-based comparative genomic hybridisation to analyse the largest series of paediatric MGCTs reported to date, representing 34 primary tumours (22 yolk sac tumours (YSTs), 11 germinomatous tumours and one metastatic embryonal carcinoma) occurring in children from birth to age 16, including 17 ovarian MGCTs. The large dataset enabled us to undertake statistical analysis, with the aim of identifying associations worthy of further investigation between patterns of genomic imbalance and clinicopathological parameters. The YSTs showed an increased frequency of 1p- (P=0.003), 3p+ (P=0.02), 4q? (P=0.07) and 6q? (P=0.004) compared to germinomatous tumours. Gain of 12p, which is invariably seen in adult MGCTs, was present in 53% of primary MGCTs of children aged 5–16 and was also observed in four of 14 YSTs affecting children less than 5. Two of these cases (14% of MGCTs in children less than 5) showed gain of the 12p11 locus considered to be particularly relevant in adult MGCTs. Gain of 12p showed a significant association with gain of 12q. Conversely, MGCTs without 12p gain displayed a significantly increased frequency of loss on 16p (P=0.04), suggesting that this imbalance may contribute to tumour development in such cases. This data provides new insight into the biology of this under-investigated tumour group and will direct future studies on the significance of specific genetic abnormalities. PMID:17285132

Palmer, R D; Foster, N A; Vowler, S L; Roberts, I; Thornton, C M; Hale, J P; Schneider, D T; Nicholson, J C; Coleman, N

2007-01-01

275

Dangerous C. Difficile Germ Infects 500,000 Americans a Year: CDC  

MedlinePLUS

... features on this page, please enable JavaScript. Dangerous C. Difficile Germ Infects 500,000 Americans a Year: ... of diagnosis, U.S. health officials report. "Infections with C. difficile have become increasingly common over the last ...

276

Analysis of Maize Seed Germs by Photoacoustic Microscopy and Photopyroelectric Technique  

NASA Astrophysics Data System (ADS)

A knowledge about thermal parameters of structural components of maize seed is of great relevance in the seed technology practice. The objective of the present study was to determine the thermal effusivity of germs of maize ( Zea mays L.) of different genotypes by means of the photopyroelectric technique (PPE) in the inverse configuration and obtaining the thermal imaging of these samples by photoacoustic microscopy (PAM). Germs from crystalline maize (white pigment), semi-crystalline maize (yellow pigment), and floury maize (blue pigment) were used in this investigation. The results show differences between germs of maize seeds mainly in the values of their thermal effusivities. The thermal images showed minimum inhomogeneity of these seed germs. Characterizations of thermal parameters in seeds are important in agriculture and food production and could be particularly useful to define their quality and determine their utility. PPE and PAM can be considered as potential diagnostic tools for the characterization of agriculture seeds.

Pacheco, A. Domínguez; Aguilar, C. Hernández; Cruz-Orea, A.

2013-05-01

277

Germ cell mutations of the ascidian Ciona intestinalis with TALE nucleases.  

PubMed

Targeted mutagenesis of genes-of-interest, or gene-knockout, is a powerful method to address the functions of genes. Engineered nucleases have enabled this approach in various organisms because of their ease of use. The ascidian Ciona intestinalis is an excellent organism to analyze gene functions by means of genetic technologies. In our previous study, we reported mutagenesis of Ciona somatic cells with TALE nucleases (TALENs) by electroporating expression constructs. In this study, we report germ cell mutagenesis of Ciona by microinjecting mRNAs encoding TALENs. TALEN mRNAs introduced mutations to target genes in both somatic and germ cells. TALEN-mediated mutations in the germ cell genome were inherited by the next generation. We conclude that knockout lines of Ciona that have disrupted target genes can be established through TALEN-mediated germ cell mutagenesis. PMID:24619765

Yoshida, Keita; Treen, Nicholas; Hozumi, Akiko; Sakuma, Tetsushi; Yamamoto, Takashi; Sasakura, Yasunori

2014-05-01

278

Autophagy is a cell survival program for female germ cells in the murine ovary.  

PubMed

It is estimated that infertility affects 15-20% of couples and can arise from female or male reproductive defects. Mouse models have ascribed roles to over 100 genes in the maintenance of female fertility. Although previous models have determined roles for apoptosis in male and female fertility, we find that compromised autophagy within the perinatal ovary, through the loss of Becn1 or Atg7, results in the premature loss of female germ cells. Becn1(+/-) ovaries have a 56% reduction of germ cells compared with control ovaries at post-natal day 1, whereas Atg7(-/-) ovaries lack discernable germ cells at this stage. Thus autophagy appears to be a cell survival mechanism to maintain the endowment of female germ cells prior to establishing primordial follicle pools in the ovary. PMID:21464117

Gawriluk, Thomas R; Hale, Amber N; Flaws, Jodi A; Dillon, Christopher P; Green, Douglas R; Rucker, Edmund B

2011-06-01

279

Germ cell-specific expression of dead end (dnd) in rare minnow (Gobiocypris rarus).  

PubMed

Rare minnow (Gobiocypris rarus) is an emerging model fish in China, and the development of its gonads is still elusive. Germ cell-specific genes are conserved in animals. Dead end (Dnd) was first documented as a germ granule component in zebrafish. Here, we report the cloning and expression profile of dnd in rare minnow. RT-PCR results showed that dnd is expressed specifically in the gonads of both sexes, is maternal in origin and is expressed continuously during embryogenesis. Dnd mRNA could be detected exclusively in the germ cells of the testis and ovary. Temporal expression of dnd mRNA is similar to that of vasa and dnd in zebrafish during embryogenesis. Taken together, dnd mRNA is restricted to the germ cells of rare minnow. PMID:25663436

Duan, Jundan; Feng, Gongqing; Chang, Pei; Zhang, Xueyan; Zhou, Qingchun; Zhong, Xueping; Qi, Chao; Xie, Songguang; Zhao, Haobin

2015-04-01

280

Moral obligation and the human germ-line gene therapy debate  

E-print Network

genetic engineering, there are few arguments made for a positive moral obligation to genetic intervention. This is especially so with respect to human germ-line gene therapy. Burke. K. Zimmerman makes one of the few arguments that society...

Clark, Alan B

1998-01-01

281

Examination of plants in lunar (germ free) soil in Plant Laboratory  

NASA Technical Reports Server (NTRS)

Dr. Charles Walkenshaw, Manned Spacecraft Center botanist, examines sorghum and tobacco plants in lunar (germ free) soil in the Plant Laboratory of the Lunar Receiving Laboratory. The soil was brought back from the Moon by the Apollo 11 astronauts.

1969-01-01

282

Fine-structural characteristics of female and male germ cells in Proseriata Otoplanidae (Platyhelminthes)  

Microsoft Academic Search

Fine-structural features of female germ cells differentiating within the germaria of Otoplanella baltica and Notocaryoplanella glandulosa are documented and compared with those of other free-living platyhelminths having ectolecithal eggs.

Beate Sopott Ehlers

1986-01-01

283

Recovering corn germ enriched in recombinant protein by wet-fractionation.  

PubMed

Corn wet-fractionation processes (quick-germ fractionation and traditional wet milling) were evaluated as means of recovering fractions rich in recombinant collagen-related proteins that were targeted for expression in the germ (embryo) of transgenic corn. Transgenic corn lines accumulating a recombinant full-length human collagen type-I-alpha-1 (full-length rCIalpha1) or a 44-kDa rCIalpha1 fragment targeted for seed expression with an embryo-specific promoter were used. Factors to consider in efficient recovery processes are the distribution of the peptides among botanical parts and process recovery efficiency. Both recombinant proteins were distributed 62-64% in germ comprising about 8.6% of the dry grain mass; 34-38% in the endosperm comprising 84% of the dry grain mass; 1.7% in the pericarp comprising about 5% of the dry mass; and 1% in the tip-cap comprising 1.5-2% of the dry mass. The quick-germ method employed a short steeping period either in water or SO(2)-lactic acid solution followed by wet-milling degermination to recover a germ-rich fraction. Of the total recombinant protein expressed in germ, the quick-germ process recovered 40-43% of the total recombinant protein within 6-8% of the corn mass. The traditional corn wet-milling process produced higher purity germ but with lower recovery (24-26%) of the recombinant protein. The two quick-germ methods, using water alone or SO(2)-lactic acid steeping, did not substantially differ in rCIalpha1 recovery, and the quick-germ processes recovered germ with less leaching and proteolytic losses of the recombinant proteins than did traditional wet milling. Thus, grain fractionation enriched the recombinant proteins 6-fold higher than that of unfractionated kernels. Such enrichment may improve downstream processing efficiency and enable utilizing the protein-lean co-products to produce biofuels and biorenewable chemicals by fermenting the remaining starch-rich fractions. PMID:19726179

Paraman, Ilankovan; Fox, Steven R; Aspelund, Matthew T; Glatz, Charles E; Johnson, Lawrence A

2010-01-01

284

Modeling cell elongation during germ band retraction: cell autonomy versus applied anisotropic stress.  

PubMed

The morphogenetic process of germ band retraction in Drosophila embryos involves coordinated movements of two epithelial tissues - germ band and amnioserosa. The germ band shortens along its rostral-caudal or head-to-tail axis, widens along its perpendicular dorsal-ventral axis, and uncurls from an initial 'U' shape. The amnioserosa mechanically assists this process by pulling on the crook of the U-shaped germ band. The amnioserosa may also provide biochemical signals that drive germ band cells to change shape in a mechanically autonomous fashion. Here, we use a finite-element model to investigate how these two contributions reshape the germ band. We do so by modeling the response to laser-induced wounds in each of the germ band's spatially distinct segments (T1-T3, A1-A9) during the middle of retraction when segments T1-A3 form the ventral arm of the 'U', A4-A7 form its crook, and A8-A9 complete the dorsal arm. We explore these responses under a range of externally applied stresses and internal anisotropy of cell edge tensions - akin to a planar cell polarity that can drive elongation of cells in a direction parallel to the minimum edge tension - and identify regions of parameter space (edge-tension anisotropy versus stress anisotropy) that best match previous experiments for each germ band segment. All but three germ band segments are best fit when the applied stress anisotropy and the edge-tension anisotropy work against one another - i.e., when the isolated effects would elongate cells in perpendicular directions. Segments in the crook of the germ band (A4-A7) have cells that elongate in the direction of maximum external stress, i.e., external stress anisotropy is dominant. In most other segments, the dominant factor is internal edge-tension anisotropy. These results are consistent with models in which the amnioserosa pulls on the crook of the germ band to mechanically assist retraction. In addition, they suggest a mechanical cue for edge-tension anisotropy whereby cells do not globally orient their internal elongation axis towards the amnioserosa, but instead orient this axis perpendicular to the local principal stress direction. PMID:24839394

Lynch, Holley E; Veldhuis, Jim; Brodland, G Wayne; Hutson, M Shane

2014-05-01

285

Modeling cell elongation during germ band retraction: cell autonomy versus applied anisotropic stress  

NASA Astrophysics Data System (ADS)

The morphogenetic process of germ band retraction in Drosophila embryos involves coordinated movements of two epithelial tissues—germ band and amnioserosa. The germ band shortens along its rostral-caudal or head-to-tail axis, widens along its perpendicular dorsal-ventral axis, and uncurls from an initial ‘U’ shape. The amnioserosa mechanically assists this process by pulling on the crook of the U-shaped germ band. The amnioserosa may also provide biochemical signals that drive germ band cells to change shape in a mechanically autonomous fashion. Here, we use a finite-element model to investigate how these two contributions reshape the germ band. We do so by modeling the response to laser-induced wounds in each of the germ band’s spatially distinct segments (T1-T3, A1-A9) during the middle of retraction when segments T1-A3 form the ventral arm of the ‘U’, A4-A7 form its crook, and A8-A9 complete the dorsal arm. We explore these responses under a range of externally applied stresses and internal anisotropy of cell edge tensions—akin to a planar cell polarity that can drive elongation of cells in a direction parallel to the minimum edge tension—and identify regions of parameter space (edge-tension anisotropy versus stress anisotropy) that best match previous experiments for each germ band segment. All but three germ band segments are best fit when the applied stress anisotropy and the edge-tension anisotropy work against one another—i.e., when the isolated effects would elongate cells in perpendicular directions. Segments in the crook of the germ band (A4-A7) have cells that elongate in the direction of maximum external stress, i.e., external stress anisotropy is dominant. In most other segments, the dominant factor is internal edge-tension anisotropy. These results are consistent with models in which the amnioserosa pulls on the crook of the germ band to mechanically assist retraction. In addition, they suggest a mechanical cue for edge-tension anisotropy whereby cells do not globally orient their internal elongation axis towards the amnioserosa, but instead orient this axis perpendicular to the local principal stress direction.

Lynch, Holley E.; Veldhuis, Jim; Brodland, G. Wayne; Hutson, M. Shane

2014-05-01

286

Deletion of Genes Implicated in Protecting the Integrity of Male Germ Cells Has Differential Effects on the Incidence of DNA Breaks and Germ Cell Loss  

PubMed Central

Background Infertility affects ?20% of couples in Europe and in 50% of cases the problem lies with the male partner. The impact of damaged DNA originating in the male germ line on infertility is poorly understood but may increase miscarriage. Mouse models allow us to investigate how deficiencies in DNA repair/damage response pathways impact on formation and function of male germ cells. We have investigated mice with deletions of ERCC1 (excision repair cross-complementing gene 1), MSH2 (MutS homolog 2, involved in mismatch repair pathway), and p53 (tumour suppressor gene implicated in elimination of germ cells with DNA damage). Principal Findings We demonstrate for the first time that depletion of ERCC1 or p53 from germ cells results in an increased incidence of unrepaired DNA breaks in pachytene spermatocytes and increased numbers of caspase-3 positive (apoptotic) germ cells. Sertoli cell-only tubules were detected in testes from mice lacking expression of ERCC1 or MSH2 but not p53. The number of sperm recovered from epididymes was significantly reduced in mice lacking testicular ERCC1 and 40% of sperm contained DNA breaks whereas the numbers of sperm were not different to controls in adult Msh2 ?/? or p53 ?/? mice nor did they have significantly compromised DNA. Conclusions These data have demonstrated that deletion of Ercc1, Msh2 and p53 can have differential but overlapping affects on germ cell function and sperm production. These findings increase our understanding of the ways in which gene mutations can have an impact on male fertility. PMID:17912366

Paul, Catriona; Povey, Joanne E.; Lawrence, Nicola J.; Selfridge, Jim; Melton, David W.; Saunders, Philippa T. K.

2007-01-01

287

An Integrative Omics Strategy to Assess the Germ Cell Secretome and to Decipher Sertoli-Germ Cell Crosstalk in the Mammalian Testis  

PubMed Central

Mammalian spermatogenesis, which takes place in complex testicular structures called seminiferous tubules, is a highly specialized process controlled by the integration of juxtacrine, paracrine and endocrine information. Within the seminiferous tubules, the germ cells and Sertoli cells are surrounded by testicular fluid (TF), which probably contains most of the secreted proteins involved in crosstalk between these cells. It has already been established that germ cells can modulate somatic Sertoli cell function through the secretion of diffusible factors. We studied the germ cell secretome, which was previously considered inaccessible, by analyzing the TF collected by microsurgery in an “integrative omics” strategy combining proteomics, transcriptomics, genomics and interactomics data. This approach identified a set of proteins preferentially secreted by Sertoli cells or germ cells. An interaction network analysis revealed complex, interlaced cell-cell dialog between the secretome and membranome of seminiferous cells, mediated via the TF. We then focused on germ cell-secreted candidate proteins, and we identified several potential interacting partners located on the surface of Sertoli cells. Two interactions, APOH/CDC42 and APP/NGFR, were validated in situ, in a proximity ligation assay (PLA). Our results provide new insight into the crosstalk between germ cells and Sertoli cells occurring during spermatogenesis. Our findings also demonstrate that this “integrative omics” strategy is powerful enough for data mining and highlighting meaningful cell-cell communication events between different types of cells in a complex tissue, via a biological fluid. This integrative strategy could be applied more widely, to gain access to secretomes that have proved difficult to study whilst avoiding the limitations of in vitro culture. PMID:25111155

Lavigne, Régis; Hernio, Nolwen; Teixeira-Gomes, Ana-Paula; Dacheux, Jean-Louis; Pineau, Charles

2014-01-01

288

Localisation of RNAs into the Germ Plasm of Vitellogenic Xenopus Oocytes  

PubMed Central

We have studied the localisation of mRNAs in full-grown Xenopus laevis oocytes by injecting fluorescent RNAs, followed by confocal microscopy of the oocyte cortex. Concentrating on RNA encoding the Xenopus Nanos homologue, nanos1 (formerly Xcat2), we find that it consistently localised into aggregated germ plasm ribonucleoprotein (RNP) particles, independently of cytoskeletal integrity. This implies that a diffusion/entrapment-mediated mechanism is active, as previously reported for previtellogenic oocytes. Sometimes this was accompanied by localisation into scattered particles of the “late”, Vg1/VegT pathway; occasionally only late pathway localisation was seen. The Xpat RNA behaved in an identical fashion and for neither RNA was the localisation changed by any culture conditions tested. The identity of the labelled RNP aggregates as definitive germ plasm was confirmed by their inclusion of abundant mitochondria and co-localisation with the germ plasm protein Hermes. Further, the nanos1/Hermes RNP particles are interspersed with those containing the germ plasm protein Xpat. These aggregates may be followed into the germ plasm of unfertilized eggs, but with a notable reduction in its quantity, both in terms of injected molecules and endogenous structures. Our results conflict with previous reports that there is no RNA localisation in large oocytes, and that during mid-oogenesis even germ plasm RNAs localise exclusively by the late pathway. We find that in mid oogenesis nanos1 RNA also localises to germ plasm but also by the late pathway. Late pathway RNAs, Vg1 and VegT, also may localise into germ plasm. Our results support the view that mechanistically the two modes of localisation are extremely similar, and that in an injection experiment RNAs might utilise either pathway, the distinction in fates being very subtle and subject to variation. We discuss these results in relation to their biological significance and the results of others. PMID:23626739

Nijjar, Sarbjit; Woodland, Hugh R.

2013-01-01

289

Apoptosis mediated by phosphatidylserine externalization in the elimination of aneuploid germ cells during human spermatogenesis.  

PubMed

It has been described that aneuploidies trigger cell cycle checkpoints leading to apoptosis. The aim of this study was to assess the relationship between the presence of chromosomal abnormalities and apoptosis in germ cells and in Sertoli cells. Fourteen diagnostic testicular biopsies from infertile patients were processed following a sequential methodology, which included enzymatic disaggregation, apoptotic staining, cell sorting, cell fixation, and fluorescent in situ hybridization analysis. The chromosome constitution of germ cells (interphase pre-meiotic germ cells, meiotic figures, post-reductional germ cells, and spermatozoa) and Sertoli cells was evaluated in non-sorted and flow-sorted cell populations (apoptotic and viable). The mean percentage of aneuploidy was compared between the three fractions in each cell type using a Kruskal-Wallis test. If significant results were obtained, a two-by-two Chi-squared test was performed. There were significant differences between the apoptotic fraction and the viable and non-sorted fractions in the pre-meiotic germ cells (p < 0.01). In the remaining cell types, no association between the presence of aneuploidy and apoptotic processes was observed, even in the case of post-reductional germ cells in which we detected the highest rates of aneuploidy regardless of the fraction analyzed. From our data, it can be inferred that most of the aneuploid post-reductional germ cells are efficiently removed from the testicular epithelium without differentiating into spermatozoa. Our results suggest that the elimination of aneuploid testicular epithelial cells is triggered by different mechanisms. Accordingly, the cellular elimination of aneuploid germ cells beyond the blood-testis barrier does not involve phosphatidylserine externalization. PMID:25213174

Garcia-Quevedo, L; Blanco, J; Sarrate, Z; Vidal, F

2014-11-01

290

Spermiogenesis deficiency and germ-cell apoptosis in CREM-mutant mice  

Microsoft Academic Search

SPERMIOGENESIS is a complex process by which postmeiotic male germ cells differentiate into mature spermatozoa. This process involves remarkable structural and biochemical changes including nuclear DNA compaction and acrosome formation1,2. Tran-scriptional activator CREM (cyclic AMP-responsive element modulator) is highly expressed in postmeiotic cells3-5, and CREM may be responsible for the activation of several haploid germ cell-specific genes involved in the

François Nantel; Lucia Monaco; Nicholas S. Foulkes; Denis Masquilier; Marianne Lemeur; Kenth Henriksén; Andrée Dierich; Martti Parvinen; Paolo Sassone-Corsi

1996-01-01

291

Mechanism of fluid and electrolyte secretion in the germ-free rat cecum  

Microsoft Academic Search

The cecum of the germ-free rat is filled with a large volume of liquid: cecum plus cecal contents comprise up to 25% of the rodent's body weight. To explain the presence of the liquid cecal contents in the germ-free rat, cecal transport of water and electrolytes was studied using a closed-loop technique with [14C]polyethylene glycol as a nonabsorbable marker. When

Mark Donowitz; Henry J. Binder

1979-01-01

292

No extension of lifespan by ablation of germ line in Drosophila  

PubMed Central

Increased reproduction is frequently associated with a reduction in longevity in a variety of organisms. Traditional explanations of this ‘cost of reproduction’ suggest that trade-offs between reproduction and longevity should be obligate. However, it is possible to uncouple the two traits in model organisms. Recently, it has been suggested that reproduction and longevity are linked by molecular signals produced by specific reproductive tissues. For example, in Caenorhabditis elegans, lifespan is extended in worms that lack a proliferating germ line, but which possess somatic gonad tissue, suggesting that these tissues are the sources of signals that mediate lifespan. In this study, we tested for evidence of such gonadal signals in Drosophila melanogaster. We ablated the germ line using two maternal effect mutations: germ cell-less and tudor. Both mutations result in flies that lack a proliferating germ line but that possess a somatic gonad. In contrast to the findings from C. elegans, we found that germ line ablated females had reduced longevity relative to controls and that the removal of the germ line led to an over-proliferation of the somatic stem cells in the germarium. Our results contrast with the widely held view that it is downstream reproductive processes such as the production and/or laying of eggs that are costly to females. In males, germ line ablation caused either no difference, or a slight extension, in longevity relative to controls. Our results indicate that early acting, upstream reproductive enabling processes are likely to be important in determining reproductive costs. In addition, we suggest that the specific roles and putative patterns of molecular signalling in the germ line and somatic tissues are not conserved between flies and worms. PMID:16627279

Barnes, Andrew I; Boone, James M; Jacobson, Jake; Partridge, Linda; Chapman, Tracey

2005-01-01

293

Viability of Female Germ-Line Cells Homozygous for Zygotic Lethals in DROSOPHILA MELANOGASTER  

PubMed Central

We have analyzed the viability of different types of X chromosomes in homozygous clones of female germ cells. The chromosomes carried viable mutations, single-cistron zygotic-lethal and semi-lethal mutations, or small (about six chromosome band) deletions. Homozygous germ-line clones were produced by recombination in females heterozygous for an X-linked, dominant, agametic female sterile. All the zygotic-viable mutants are also viable in germ cells. Of 16 deletions tested (uncovering a total of 93 bands) only 2 (of 4 and 5 bands) are germ-cell viable. Mutations in 15 lethal complementation groups in the zeste-white region were tested. When known, the most extreme alleles at each locus were tested. Only in five loci (33%) were the mutants viable in the germ line. Similar studies of the same deletions and point-mutant lethals in epidermal cells show that 42% of the bands and 77% of the lethal alleles are viable. Thus, germ-line cells have more stringent cell-autonomous genetic requirements than do epidermal cells. The eggs recovered from clones of three of the germ-cell viable zw mutations gave embryos arrested early in embryogenesis, although genotypically identical embryos derived from heterozygous oogonia die as larvae or even hatch as adult escapers. For two genes, homozygosis of the mutations tested also caused embryonic arrest of heterozygous female embryos, and in one case, the eggs did not develop at all. Germ-line clones of one quite leaky mutation gave eggs that were indistinguishable from normal. The abundance of genes whose products are required for oogenesis, whose products are required in the oocyte, and whose activity is required during zygotic development is discussed. PMID:17246109

Garcia-Bellido, Antonio; Robbins, Leonard G.

1983-01-01

294

Germ cells of the centipede Strigamia maritima are specified early in embryonic development  

PubMed Central

We provide the first systematic description of germ cell development with molecular markers in a myriapod, the centipede Strigamia maritima. By examining the expression of Strigamia vasa and nanos orthologues, we find that the primordial germ cells are specified from at least the blastoderm stage. This is a much earlier embryonic stage than previously described for centipedes, or any other member of the Myriapoda. Using these genes as markers, and taking advantage of the developmental synchrony of Strigamia embryos within single clutches, we are able to track the development of the germ cells throughout embryogenesis. We find that the germ cells accumulate at the blastopore; that the cells do not internalize through the hindgut, but rather through the closing blastopore; and that the cells undergo a long-range migration to the embryonic gonad. This is the first evidence for primordial germ cells displaying these behaviours in any myriapod. The myriapods are a phylogenetically important group in the arthropod radiation for which relatively little developmental data is currently available. Our study provides valuable comparative data that complements the growing number of studies in insects, crustaceans and chelicerates, and is important for the correct reconstruction of ancestral states and a fuller understanding of how germ cell development has evolved in different arthropod lineages. PMID:24930702

Green, Jack E.; Akam, Michael

2014-01-01

295

Isoprenoids control germ cell migration downstream of HMGCoA reductase.  

PubMed

3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCoAr) provides attractive cues to Drosophila germ cells, guiding them toward the embryonic gonad. However, it remains unclear how HMGCoAr mediates this attraction. In a genomic analysis of the HMGCoAr pathway, we found that the fly genome lacks several enzymes required for cholesterol biosynthesis, ruling out cholesterol and cholesterol-derived proteins as mediators of PGC migration. Genetic analysis of the pathway revealed that two enzymes, farnesyl-diphosphate synthase and geranylgeranyl-diphosphate synthase, required for the production of isoprenoids, act downstream of HMGCoAr in germ cell migration. Consistent with a role in geranylgeranylation, embryos deficient in geranylgeranyl transferase type I show germ cell migration defects. Our data, together with similar findings in zebrafish, implicate an isoprenylated protein in germ cell attraction. The specificity and evolutionary conservation of the HMGCoAr pathway for germ cells suggest that an attractant common to invertebrates and vertebrates guides germ cells in early embryos. PMID:14960281

Santos, Ana C; Lehmann, Ruth

2004-02-01

296

A late phase of germ plasm accumulation during Drosophila oogenesis requires Lost and Rumpelstiltskin  

PubMed Central

Asymmetric mRNA localization is an effective mechanism for establishing cellular and developmental polarity. Posterior localization of oskar in the Drosophila oocyte targets the synthesis of Oskar to the posterior, where Oskar initiates the assembly of the germ plasm. In addition to harboring germline determinants, the germ plasm is required for localization and translation of the abdominal determinant nanos. Consequently, failure of oskar localization during oogenesis results in embryos lacking germ cells and abdominal segments. oskar accumulates at the oocyte posterior during mid-oogenesis through a well-studied process involving kinesin-mediated transport. Through live imaging of oskar mRNA, we have uncovered a second, mechanistically distinct phase of oskar localization that occurs during late oogenesis and results in amplification of the germ plasm. Analysis of two newly identified oskar localization factors, Rumpelstiltskin and Lost, that are required specifically for this late phase of oskar localization shows that germ plasm amplification ensures robust abdomen and germ cell formation during embryogenesis. In addition, our results indicate the importance of mechanisms for adapting mRNAs to utilize multiple localization pathways as necessitated by the dramatic changes in ovarian physiology that occur during oogenesis. PMID:21752933

Sinsimer, Kristina S.; Jain, Roshan A.; Chatterjee, Seema; Gavis, Elizabeth R.

2011-01-01

297

[Primary hyperchylomicronemia].  

PubMed

Primary hyperchylomicronemia is characterized by a marked hypertriglyceridemia due to an increase in chylomicrons, which may cause acute pancreatitis and eruptive xanthomas. This entity includes familial lipoprotein lipase (LPL) deficiency, familial apolipoprotein C-II deficiency, primary type V hyperlipoproteinemia, and idiopathic hyperchylomicronemia. Idiopathic hyperchylomicronemia is caused by an LPL inhibitor or autoantibody against LPL. More recently, patients with primary hyperchylomicronemia caused by mutations in the gene for glycosylphosphatidylinositol-anchored high density lipoprotein-binding protein 1(GPIHBP1) or lipase maturation factor 1(LMF1). For the treatment of primary hyperchylomicronemia, a strict restriction of dietary fat is essential to avoid acute pancreatitis. PMID:24205717

Yamashita, Shizuya

2013-09-01

298

Fermented wheat germ extract - nutritional supplement or anticancer drug?  

PubMed Central

Background Fermented wheat germ extract (FWGE) is a multisubstance composition and, besides others, contains 2-methoxy benzoquinone and 2, 6-dimethoxy benzoquinone which are likely to exert some of its biological effects. FWGE interferes with anaerobic glycolysis, pentose cycle and ribonucleotide reductase. It has significant antiproliferative effects and kills tumor cells by the induction of apoptosis via the caspase-poly [ADP-ribose] polymerase-pathway. FWGE interacts synergistically with a variety of different anticancer drugs and exerted antimetastatic properties in mouse models. In addition, FWGE modulates immune response by downregulation of MHC-I complex and the induction of TNF-? and various interleukins. Data in the F-344 rat model provide evidence for a colon cancer preventing effect of FWGE. Clinical data from a randomized phase II trial in melanoma patients indicate a significant benefit for patients treated with dacarbazine in combination with FWGE in terms of progression free survival (PFS) and overall survival (OS). Similarly, data from studies in colorectal cancer suggested a benefit of FWGE treatment. Besides extension of OS and PFS, FWGE improved the quality of life in several studies. Conclusion In conclusion, available data so far, justify the use of FWGE as a non-prescription medical nutriment for cancer patients. Further randomized, controlled and large scale clinical studies are mandatory, to further clarify the value of FWGE as a drug component of future chemotherapy regimens. PMID:21892933

2011-01-01

299

Interspecific germline transmission of cultured primordial germ cells.  

PubMed

In birds, the primordial germ cell (PGC) lineage separates from the soma within 24 h following fertilization. Here we show that the endogenous population of about 200 PGCs from a single chicken embryo can be expanded one million fold in culture. When cultured PGCs are injected into a xenogeneic embryo at an equivalent stage of development, they colonize the testis. At sexual maturity, these donor PGCs undergo spermatogenesis in the xenogeneic host and become functional sperm. Insemination of semen from the xenogeneic host into females from the donor species produces normal offspring from the donor species. In our model system, the donor species is chicken (Gallus domesticus) and the recipient species is guinea fowl (Numida meleagris), a member of a different avian family, suggesting that the mechanisms controlling proliferation of the germline are highly conserved within birds. From a pragmatic perspective, these data are the basis of a novel strategy to produce endangered species of birds using domesticated hosts that are both tractable and fecund. PMID:22629301

van de Lavoir, Marie-Cecile; Collarini, Ellen J; Leighton, Philip A; Fesler, Jeffrey; Lu, Daniel R; Harriman, William D; Thiyagasundaram, T S; Etches, Robert J

2012-01-01

300

Pathogen germs response to low-dose radiation — medical approach  

NASA Astrophysics Data System (ADS)

The side effects of radiation therapy in the case of microbial loading of irradiated organs was considered as phenomenological basis of the experiment carried out on Staphylococcus aureus (ATCC germ) exposed to low X-ray doses. The inoculum was prepared in a liquid culture medium with standard composition, the volumes of 3 ml identical samples (in sterile glass tubes) being irradiated in hospital conditions. Five experimental variants were developed corresponding to irradiation time durations between 25 and 100 minutes. The spectro-colorimetric assay was accomplished at 560 nm and 420 nm, the resulting average values (for three repetitions) being analyzed from the viewpoint of cell density in the irradiated variants compared to control ones. The resistance to antibiotics of the irradiated bacteria was tested on agarized cultures against five antibiotic molecules (ampicillin, cloramphenicol, tetracycline, tobramicin and ofloxacin) by assessing the diameter of inhibition growth areas in each case. The increase of the inhibition area diameter with up to 15% (in the case of tetracycline) was noticed for the lowest irradiation time for all five antibiotics, which is suggesting a weakening of the bacteria resistance to the pharmaceutical agents following the X-ray treatment. This was concordant with the results of the spectro-colorimetric assay of the cell density within the directly irradiated bacteria cultures. The main issue of this study is concerning the optimization of the radiotherapy protocol in patients with potential microbial loading.

Poiata, A.; Focea, R.; Creanga, D.

2012-04-01

301

[A mixed germ cell tumor that underwent dramatic size changes].  

PubMed

This report describes a mixed germ cell tumor that underwent dramatic size changes. A 12-year-old boy presented to our hospital with a headache that had persisted for two months. Initial magnetic resonance imaging (MRI) revealed a pineal tumor and hydrocephalus. The patient required external ventricular drainage and underwent two endoscopic biopsies. His evaluation involved a total of nine computed tomography (CT) scans prior to the second biopsy;the tumor size had decreased before the second endoscopic biopsy. The tumor consisted of both a germinoma and a teratoma component. The patient was treated with three courses of carboplatin-etoposide (CBDCA-VP) chemotherapy and whole-ventricle radiotherapy (32.1 Gy). However, during the adjuvant therapy, the tumor size increased, necessitating total tumor resection. We speculate that the tumor's initial size reduction was caused by leakage of the cyst component and exposure to the brain CT irradiation. The tumor's subsequent increase in size was due to the recollection of the cystic components and intracranial growing teratoma syndrome (iGTS). Therefore, frequent brain CTs and angiography should be avoided before definitive pathological diagnosis is achieved. Further, the tumor size should be considered, with surgical resection being performed at the optimal time. PMID:25179200

Kuwayama, Kazuyuki; Takai, Hiroki; Nishiyama, Akira; Hirai, Satoshi; Yokosuka, Kimihiko; Toi, Hiroyuki; Hirano, Kazuhiro; Matsubara, Shunji; Uno, Masaaki; Nishimura, Hirotake

2014-09-01

302

[Germ cell tumors of the testes: state of the art].  

PubMed

Germ cell tumors of the testes are rare tumors occurring in young men, the incidence of which increases continuously. They are curable in more than 80% of the cases. The treatment of stage I seminoma is lomboaortic radiotherapy, and that of stage I non-seminomatous tumors is either surveillance, retroperitoneal lymph node dissection or adjuvant chemotherapy according to the risk factors of extra-testicular involvement (pure embryonal carcinoma, vascular invasion). For advanced diseases, the standard treatment is three cycles of bleomycin, etoposide, cisplatin (BEP regimen) or four cycles of the same association without bleomycin (EP regimen) and four cycles of the BEP regimen for patients with good risk and poor risk prognostic characteristics, respectively. The five-year overall survival rates are 90% and 50% for patients with good risk and poor risk factors respectively. It is recommended to resect all residual masses after chemotherapy. The standard salvage treatment is four cycles of vinblastin, ifosfamide, cisplatin (VelP regimen). New associations of drugs are under study in order to improve the overall survival rate for the poor-risk and relapsed-tumors patients. PMID:10742806

Fléchon, A; Droz, J P

2000-01-01

303

NANOG priming before full reprogramming may generate germ cell tumours.  

PubMed

Reprogramming somatic cells into a pluripotent state brings patient-tailored, ethical controversy-free cellular therapy closer to reality. However, stem cells and cancer cells share many common characteristics; therefore, it is crucial to be able to discriminate between them. We generated two induced pluripotent stem cell (iPSC) lines, with NANOG pre-transduction followed by OCT3/4, SOX2, and LIN28 overexpression. One of the cell lines, CHiPS W, showed normal pluripotent stem cell characteristics, while the other, CHiPS A, though expressing pluripotency markers, failed to differentiate and gave rise to germ cell-like tumours in vivo. Comparative genomic hybridisation analysis of the generated iPS lines revealed that they were genetically more stable than human embryonic stem cell counterparts. This analysis proved to be predictive for the differentiation potential of analysed cells. Moreover, the CHiPS A line expressed a lower ratio of p53/p21 when compared to CHiPS W. NANOG pre-induction followed by OCT3/4, SOX2, MYC, and KLF4 induction resulted in the same tumour-inducing phenotype. These results underline the importance of a re-examination of the role of NANOG during reprogramming. Moreover, this reprogramming method may provide insights into primordial cell tumour formation and cancer stem cell transformation. PMID:22071697

Grad, I; Hibaoui, Y; Jaconi, M; Chicha, L; Bergström-Tengzelius, R; Sailani, M R; Pelte, M F; Dahoun, S; Mitsiadis, T A; Töhönen, V; Bouillaguet, S; Antonarakis, S E; Kere, J; Zucchelli, M; Hovatta, O; Feki, A

2011-01-01

304

The Origin And Migration Of Primordial Germ Cells In Sturgeons  

PubMed Central

Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts. PMID:24505272

Saito, Taiju; Pšeni?ka, Martin; Goto, Rie; Adachi, Shinji; Inoue, Kunio; Arai, Katsutoshi; Yamaha, Etsuro

2014-01-01

305

The origin and migration of primordial germ cells in sturgeons.  

PubMed

Primordial germ cells (PGCs) arise elsewhere in the embryo and migrate into developing gonadal ridges during embryonic development. In several model animals, formation and migration patterns of PGCs have been studied, and it is known that these patterns vary. Sturgeons (genus Acipenser) have great potential for comparative and evolutionary studies of development. Sturgeons belong to the super class Actinoptergii, and their developmental pattern is similar to that of amphibians, although their phylogenetic position is an out-group to teleost fishes. Here, we reveal an injection technique for sturgeon eggs allowing visualization of germplasm and PGCs. Using this technique, we demonstrate that the PGCs are generated at the vegetal pole of the egg and they migrate on the yolky cell mass toward the gonadal ridge. We also provide evidence showing that PGCs are specified by inheritance of maternally supplied germplasm. Furthermore, we demonstrate that the migratory mechanism is well-conserved between sturgeon and other remotely related teleosts, such as goldfish, by a single PGCs transplantation (SPT) assay. The mode of PGCs specification in sturgeon is similar to that of anurans, but the migration pattern resembles that of teleosts. PMID:24505272

Saito, Taiju; Pšeni?ka, Martin; Goto, Rie; Adachi, Shinji; Inoue, Kunio; Arai, Katsutoshi; Yamaha, Etsuro

2014-01-01

306

Mediastinal germ cell tumour causing superior vena cava tumour thrombosis.  

PubMed

We report a rare case of a 35-year-old man who presented with a 1-week history of retrosternal chest pain of moderate intensity. A positron emission tomography CT (PET-CT) showed a large fluorodeoxy-glucose (FDG)-avid heterogeneously enhancing necrotic mass in the anterosuperior mediastinum with a focal FDG-avid thrombosis of the superior vena cava (SVC) suggestive of tumour thrombus and vascular invasion. ?-Fetoprotein levels were raised (5690?IU/L). Image guided biopsy of the mediastinal mass was suggestive of non-seminomatous germ cell tumour (NSGCT). The patient received four cycles of BEP (bleomycin, etoposide and cisplatin) along with therapeutic anticoagulation with low-molecular-weight heparin. Follow-up whole body PET-CT revealed complete resolution of mediastinal mass and SVC tumour thrombosis. The documentation of FDG-PET-avid tumour thrombus resolving with chemotherapy supports the concept of circulating tumour cells being important not only in common solid tumours such as breast and colon cancer but also in relatively less common tumours such as NSGCT. The detection of circulating tumour cells could help deploy aggressive regimens upfront. PMID:25809431

Karanth, Suman S; Vaid, Ashok K; Batra, Sandeep; Sharma, Devender

2015-01-01

307

Global deletion of Trp53 reverts ovarian tumor phenotype of the germ cell-deficient white spotting variant (wv) mice.  

PubMed

White spotting variant (Wv) mice are spontaneous mutants attributed to a point mutation in the c-Kit gene, which reduces the tyrosine kinase activity to around 1% and affects the development of melanocytes, mast cells, and germ cells. Homozygous mutant mice are sterile but can live nearly a normal life span. The female Wv mice have a greatly reduced ovarian germ cell and follicle reserve at birth, and the remaining follicles are largely depleted soon after the females reach reproductive stage at around 7 weeks of age. Consequently, ovarian epithelial tumors develop in 100% of Wv females by 3 to 4 months of age. These tumors, called tubular adenomas, are benign but can become invasive in older Wv mice. We tested if additional genetic mutation(s) could convert the benign ovarian epithelial tumors to malignant tumors by crossing the Wv mutant into the Trp53 knockout background. Surprisingly, we found that global deletion of Trp53 suppressed the development of ovarian tubular adenomas in Wv mice. The ovaries of Wv/Wv; Trp53 (-/-) mice were covered by a single layer of surface epithelium and lacked excessive epithelial proliferation. Rather, the ovaries contained a small number of follicles. The presence of ovarian follicles and granulosa cells, as indicated by Pgc7 and inhibin-alpha expression, correlated with the absence of epithelial lesions. A reduction of Pten gene dosage, as in Wv/Wv; Pten (+/-) mice, produced a similar, though less dramatic, phenotype. We conclude that deletion of Trp53 prolongs the survival of ovarian follicles in Wv mice and consequently prevents the proliferation of ovarian epithelial cells and development of ovarian tubular adenomas. The results suggest that various cell types within the ovary communicate and mutually modulate, and an intact tissue environment is required to ensure homeostasis of ovarian surface epithelial cells. Especially, the current finding emphasizes the importance of ovarian follicles in suppressing the hyperplastic growth of ovarian epithelial cells, dominating over the loss of p53. PMID:25622902

Cai, Kathy Qi; Wang, Ying; Smith, Elizabeth R; Smedberg, Jennifer L; Yang, Dong-Hua; Yang, Wan-Lin; Xu, Xiang-Xi

2015-01-01

308

Survival of patients with nonseminomatous germ cell cancer: a review of the IGCC classification by Cox regression and recursive partitioning.  

PubMed

The International Germ Cell Consensus (IGCC) classification identifies good, intermediate and poor prognosis groups among patients with metastatic nonseminomatous germ cell tumours (NSGCT). It uses the risk factors primary site, presence of nonpulmonary visceral metastases and tumour markers alpha-fetoprotein (AFP), human chorionic gonadotrophin (HCG) and lactic dehydrogenase (LDH). The IGCC classification is easy to use and remember, but lacks flexibility. We aimed to examine the extent of any loss in discrimination within the IGCC classification in comparison with alternative modelling by formal weighing of the risk factors. We analysed survival of 3048 NSGCT patients with Cox regression and recursive partitioning for alternative classifications. Good, intermediate and poor prognosis groups were based on predicted 5-year survival. Classifications were further refined by subgrouping within the poor prognosis group. Performance was measured primarily by a bootstrap corrected c-statistic to indicate discriminative ability for future patients. The weights of the risk factors in the alternative classifications differed slightly from the implicit weights in the IGCC classification. Discriminative ability, however, did not increase clearly (IGCC classification, c=0.732; Cox classification, c=0.730; Recursive partitioning classification, c=0.709). Three subgroups could be identified within the poor prognosis groups, resulting in classifications with five prognostic groups and slightly better discriminative ability (c=0.740). In conclusion, the IGCC classification in three prognostic groups is largely supported by Cox regression and recursive partitioning. Cox regression was the most promising tool to define a more refined classification. British Journal of Cancer (2004) 90, 1176-1183. doi:10.1038/sj.bjc.6601665 www.bjcancer.com Published online 24 February 2004 PMID:15026798

van Dijk, M R; Steyerberg, E W; Stenning, S P; Dusseldorp, E; Habbema, J D F

2004-03-22

309

Environmental Tobacco Smoke Exposure during Intrauterine Period, Promotes Caspase Dependent and Independent DNA Fragmentation in Sertoli-Germ Cells  

PubMed Central

Objectives. To investigate the effect of cigarette smoke exposure during intrauterine period on neonatal rat testis. Methods. Twenty-five rats were randomized to be exposed to cigarette smoke with the Walton Smoking Machine or to room air during their pregnancies. The newborn male rats (n = 21) were grouped as group 1 (n = 15) which were exposed to cigarette smoke during intrauterine life and group 2 (n = 6) which were exposed to room air during intrauterine life. The orchiectomy materials were analyzed with TUNEL immunofluorescent staining for detection of DNA damage. To detect apoptosis, immunohistochemical analyses with caspase-3 were performed. Primary outcomes were apoptotic index and immunohistochemical scores (HSCORES); secondary outcomes were Sertoli-cell count and birth-weight of rats. Results. Sertoli cell apoptosis was increased in group 1 (HSCORE = 210.6 ± 41.9) when compared to group 2 (HSCORE = 100.0 ± 17.8) (P = 0.001). Sertoli cell count was decreased in group 1 (P = 0.043). The HSCORE for the germ cells was calculated as 214.0 ± 46.2 in group 1 and 93.3 ± 10.3 in group 2 (P = 0.001) referring to an increased germ cell apoptosis in group 1. The apoptotic indexes for group 1 were 49.6 ± 9.57 and 29.98 ± 2.34 for group 2 (P = 0.001). The immunofluorescent technique demonstrated increased DNA damage in seminiferous epithelium in group 1. Conclusions. Intrauterine exposure to cigarette smoke adversely affects neonatal testicular structuring and diminishes testicular reserve. PMID:25045542

Yüksel, Beril; Kilic, Sevtap; Lortlar, Nese; Tasdemir, Nicel; Sertyel, Semra; Bardakci, Yesim; Aksu, Tarik; Batioglu, Sertaç

2014-01-01

310

A context-dependent combination of Wnt receptors controls axis elongation and leg development in a short germ insect.  

PubMed

Short germ embryos elongate their primary body axis by consecutively adding segments from a posteriorly located growth zone. Wnt signalling is required for axis elongation in short germ arthropods, including Tribolium castaneum, but the precise functions of the different Wnt receptors involved in this process are unclear. We analysed the individual and combinatorial functions of the three Wnt receptors, Frizzled-1 (Tc-Fz1), Frizzled-2 (Tc-Fz2) and Frizzled-4 (Tc-Fz4), and their co-receptor Arrow (Tc-Arr) in the beetle Tribolium. Knockdown of gene function and expression analyses revealed that Frizzled-dependent Wnt signalling occurs anteriorly in the growth zone in the presegmental region (PSR). We show that simultaneous functional knockdown of the Wnt receptors Tc-fz1 and Tc-fz2 via RNAi resulted in collapse of the growth zone and impairment of embryonic axis elongation. Although posterior cells of the growth zone were not completely abolished, Wnt signalling within the PSR controls axial elongation at the level of pair-rule patterning, Wnt5 signalling and FGF signalling. These results identify the PSR in Tribolium as an integral tissue required for the axial elongation process, reminiscent of the presomitic mesoderm in vertebrates. Knockdown of Tc-fz1 alone interfered with the formation of the proximo-distal and the dorso-ventral axes during leg development, whereas no effect was observed with single Tc-fz2 or Tc-fz4 RNAi knockdowns. We identify Tc-Arr as an obligatory Wnt co-receptor for axis elongation, leg distalisation and segmentation. We discuss how Wnt signalling is regulated at the receptor and co-receptor levels in a dose-dependent fashion. PMID:21652652

Beermann, Anke; Prühs, Romy; Lutz, Rebekka; Schröder, Reinhard

2011-07-01

311

A context-dependent combination of Wnt receptors controls axis elongation and leg development in a short germ insect  

PubMed Central

Short germ embryos elongate their primary body axis by consecutively adding segments from a posteriorly located growth zone. Wnt signalling is required for axis elongation in short germ arthropods, including Tribolium castaneum, but the precise functions of the different Wnt receptors involved in this process are unclear. We analysed the individual and combinatorial functions of the three Wnt receptors, Frizzled-1 (Tc-Fz1), Frizzled-2 (Tc-Fz2) and Frizzled-4 (Tc-Fz4), and their co-receptor Arrow (Tc-Arr) in the beetle Tribolium. Knockdown of gene function and expression analyses revealed that Frizzled-dependent Wnt signalling occurs anteriorly in the growth zone in the presegmental region (PSR). We show that simultaneous functional knockdown of the Wnt receptors Tc-fz1 and Tc-fz2 via RNAi resulted in collapse of the growth zone and impairment of embryonic axis elongation. Although posterior cells of the growth zone were not completely abolished, Wnt signalling within the PSR controls axial elongation at the level of pair-rule patterning, Wnt5 signalling and FGF signalling. These results identify the PSR in Tribolium as an integral tissue required for the axial elongation process, reminiscent of the presomitic mesoderm in vertebrates. Knockdown of Tc-fz1 alone interfered with the formation of the proximo-distal and the dorso-ventral axes during leg development, whereas no effect was observed with single Tc-fz2 or Tc-fz4 RNAi knockdowns. We identify Tc-Arr as an obligatory Wnt co-receptor for axis elongation, leg distalisation and segmentation. We discuss how Wnt signalling is regulated at the receptor and co-receptor levels in a dose-dependent fashion. PMID:21652652

Beermann, Anke; Prühs, Romy; Lutz, Rebekka; Schröder, Reinhard

2011-01-01

312

European Consensus Conference on Diagnosis and Treatment of Germ Cell Cancer: A Report of the Second Meeting of the European Germ Cell Cancer Consensus group (EGCCCG): Part I  

Microsoft Academic Search

ObjectivesThe first consensus report presented by the European Germ Cell Cancer Consensus Group (EGCCCG) in the year 2004 has found widespread approval by many colleagues throughout the world. In November 2006, the group met a second time under the auspices of the Department of Urology of the Amsterdam Medical Center, Amsterdam, The Netherlands.

Susanne Krege; Jörg Beyer; Rainer Souchon; Peter Albers; Walter Albrecht; Ferran Algaba; Michael Bamberg; István Bodrogi; Carsten Bokemeyer; Eva Cavallin-Ståhl; Johannes Classen; Christoph Clemm; Gabriella Cohn-Cedermark; Stéphane Culine; Gedske Daugaard; Pieter H. M. De Mulder; Maria De Santis; Maike de Wit; Ronald de Wit; Hans Günter Derigs; Klaus-Peter Dieckmann; Annette Dieing; Jean-Pierre Droz; Martin Fenner; Karim Fizazi; Aude Flechon; Sophie D. Fosså; Xavier Garcia del Muro; Thomas Gauler; Lajos Geczi; Arthur Gerl; Jose Ramon Germa-Lluch; Silke Gillessen; Jörg T. Hartmann; Michael Hartmann; Axel Heidenreich; Wolfgang Hoeltl; Alan Horwich; Robert Huddart; Michael Jewett; Johnathan Joffe; William G. Jones; László Kisbenedek; Olbjørn Klepp; Sabine Kliesch; Kai Uwe Koehrmann; Christian Kollmannsberger; Markus Kuczyk; Pilar Laguna; Oscar Leiva Galvis; Volker Loy; Malcolm D. Mason; Graham M. Mead; Rolf Mueller; Craig Nichols; Nicola Nicolai; Tim Oliver; Dalibor Ondrus; Gosse O. N. Oosterhof; Luis Paz Ares; Giorgio Pizzocaro; Jörg Pont; Tobias Pottek; Tom Powles; Oliver Rick; Giovanni Rosti; Roberto Salvioni; Jutta Scheiderbauer; Hans-Ulrich Schmelz; Heinz Schmidberger; Hans-Joachim Schmoll; Mark Schrader; Felix Sedlmayer; Niels E. Skakkebaek; Aslam Sohaib; Sergei Tjulandin; Padraig Warde; Stefan Weinknecht; Lothar Weissbach; Christian Wittekind; Eva Winter; Lori Wood; Hans von der Maase

2008-01-01

313

Expression pattern of Bombyx vasa -like (BmVLG) protein and its implications in germ cell development  

Microsoft Academic Search

Germ cell development in the silkworm Bombyx mori is interesting in that the species has no recognizable germ plasm, and its germ cells appear first on the ventral side of\\u000a the embryo, not on the posterior pole as in Drosophila melanogaster. We previously reported the isolation of a vasa homologue (BmVLG) from B. mori and revealed the specific expression of

Hajime Nakao; Masatsugu Hatakeyama; Jae Min Lee; Masami Shimoda; Toshio Kanda

2006-01-01

314

Gut microbiota and lipopolysaccharide content of the diet influence development of regulatory T cells: studies in germ-free mice  

Microsoft Academic Search

BACKGROUND: Mammals are essentially born germ-free but the epithelial surfaces are promptly colonized by astounding numbers of bacteria soon after birth. The most extensive microbial community is harbored by the distal intestine. The gut microbiota outnumber ~10 times the total number of our somatic and germ cells. The host-microbiota relationship has evolved to become mutually beneficial. Studies in germ-free mice

Tomas Hrncir; Renata Stepankova; Hana Kozakova; Tomas Hudcovic; Helena Tlaskalova-Hogenova

2008-01-01

315

The effects of humanin and its analogues on male germ cell apoptosis induced by chemotherapeutic drugs.  

PubMed

Human (HN) prevents stress-induced apoptosis in many cells/tissues. In this study we showed that HN ameliorated chemotherapy [cyclophosphamide (CP) and Doxorubicin (DOX)]-induced male germ cell apoptosis both ex vivo in seminiferous tubule cultures and in vivo in the testis. HN acts by several putative mechanisms via binding to: an IL-12 like trimeric membrane receptor; BAX; or insulin-like growth factor binding protein-3 (IGFBP-3, a proapoptotic factor). To understand the mechanisms of HN on male germ cell apoptosis, we studied five HN analogues including: HNG (HN-S14G, a potent agonist), HNG-F6A (no binding to IGFBP-3), HN-S7A (no self-dimerization), HN-C8P (no binding to BAX), and HN-L12A (a HN antagonist) on CP-induced male germ cell apoptosis in mice. CP-induced germ cell apoptosis was inhibited by HN, HNG, HNG-F6A, HN-S7A, and HN-C8P (less effective); but not by HN-L12A. HN-L12A, but not HN-S7A or HN-C8P, blocked the protective effect of HN against CP-induced male germ cell apoptosis. HN, HN-S7A, and HN-C8P restored CP-suppressed STAT3 phosphorylation. These results suggest that HN: (1) decreases DOX (ex vivo) and CP (in vivo) induced male germ cell apoptosis; (2) action is mediated by the membrane receptor/STAT3 with minor contribution by BAX-binding pathway; (3) self-dimerization or binding to IGFBP-3 may not be involved in HN's effect in testis. HN is an important molecule in the regulation of germ cell homeostasis after injury and agonistic analogues may be developed for treating male infertility or protection against chemotherapy side effects. PMID:25666707

Jia, Yue; Ohanyan, Aikoui; Lue, Yan-He; Swerdloff, Ronald S; Liu, Peter Y; Cohen, Pinchas; Wang, Christina

2015-04-01

316

Male Differentiation of Germ Cells Induced by Embryonic Age-Specific Sertoli Cells in Mice1  

PubMed Central

ABSTRACT Retinoic acid (RA) is a meiosis-inducing factor. Primordial germ cells (PGCs) in the developing ovary are exposed to RA, resulting in entry into meiosis. In contrast, PGCs in the developing testis enter mitotic arrest to differentiate into prospermatogonia. Sertoli cells express CYP26B1, an RA-metabolizing enzyme, providing a simple explanation for why XY PGCs do not initiate meios/is. However, regulation of entry into mitotic arrest is likely more complex. To investigate the mechanisms that regulate male germ cell differentiation, we cultured XX and XY germ cells at 11.5 and 12.5 days postcoitus (dpc) with an RA receptor inhibitor. Expression of Stra8, a meiosis initiation gene, was suppressed in all groups. However, expression of Dnmt3l, a male-specific gene, during embryogenesis was elevated but only in 12.5-dpc XY germ cells. This suggests that inhibiting RA signaling is not sufficient for male germ cell differentiation but that the male gonadal environment also contributes to this pathway. To define the influence of Sertoli cells on male germ cell differentiation, Sertoli cells at 12.5, 15.5, and 18.5 dpc were aggregated with 11.5 dpc PGCs, respectively. After culture, PGCs aggregated with 12.5 dpc Sertoli cells increased Nanos2 and Dnmt3l expression. Furthermore, these PGCs established male-specific methylation imprints of the H19 differentially methylated domains. In contrast, PGCs aggregated with Sertoli cells at late embryonic ages did not commit to the male pathway. These findings suggest that male germ cell differentiation is induced both by inhibition of RA signaling and by molecule(s) production by embryonic age-specific Sertoli cells. PMID:22262692

Ohta, Kohei; Yamamoto, Miyuki; Lin, Yanling; Hogg, Nathanael; Akiyama, Haruhiko; Behringer, Richard R.; Yamazaki, Yukiko

2012-01-01

317

Model of the biotic cycle "plants germs - microorganisms" by affect heavy metal salts  

NASA Astrophysics Data System (ADS)

The growth of wheat germ roots exposed to heavy metal salts (ZnSO4) was studied experimentally and theoretically. During the experiment the plant seeds were preliminarily treated with an experimental microbial association. As a result, data were obtained about the decrease of the inhibiting effect of zinc on the growth of wheat germ roots where the seeds had been treated with the microbial association. To understand such effect, calculations were made to reveal the specific growth rate of a germ root depending on the inhibitor concentration with and without microorganism association treatment. It was shown that in case with the wheat germ roots the seeds of which had been treated with the microorganisms the inhibition constant (kI = 45 MPC (Maximum Permissible Concentration) was higher than in the case with the roots growing out of the seeds that hadn't been treated with the microorganisms (kI = 32 MPC). One of possible reasons for the decrease of growth inhibition of wheat germ roots by zinc salt is the protective function of microorganism's treatment of the seeds. To verify and confirm the experimental results, a mathematical model was created imitating the interaction between wheat germ roots and microbial association exposed to an inhibitor. Investigation of the model proved that the microbial association has a positive effect on the growth of wheat germ roots exposed to an inhibitor. The experimental and theoretical results agreed quantitatively. It was found out that the increase of the inhibitor concentration led to the effect of maximum relief of zinc inhibiting impact. The work is supported by grants Yenissei 07-04-96806.

Pisman, Tamara

318

Anti-Oxidant and Anti-Adipogenic Effects of Ethanol Extracts from Wheat Germ and Wheat Germ Fermented with Aspergillus oryzae  

PubMed Central

Most of the wheat germ in cereal grains is removed during the milling process. Various physiological effects have been reported for bioactive substances in wheat germ such as phenolic acids and flavonoids. In this study, the anti-oxidant and anti-adipogenic effects of ethanol extracts from wheat germ (WGE) and wheat germ fermented with Aspergillus oryzae (F-WGE) were investigated in HepG2 and 3T3-L1 cells. The anti-oxidant activity of F-WGE was demonstrated by a dose-dependent increase in the enhanced scavenging capacity of hydroxyl radicals and Cu2+-chelating activity compared to WGE. WGE and F-WGE treatment at doses between 10 and 400 ?g/mL did not affect the viability of HepG2 and 3T3-L1 cells. Intracellular ROS levels from Cu2+-induced oxidative stress were significantly decreased by F-WGE treatment in HepG2 cells compared to WGE. Lipid accumulation was increased in 3T3-L1 adipocytes by 100 ?M Fe2+ treatment, but the accumulation was strongly inhibited by 100 ?g/mL of WGE and F-WGE treatment. These results suggest that changes in bioactive substances during the fermentation of wheat germ can potentiate scavenging activities against transition metal-induced oxidative stress and lipid accumulation in 3T3-L1 adipocytes. Therefore, we propose that F-WGE is a novel food materials and provided scientific evidences for its efficacy in the development of functional foods.

Park, Euna; Kim, Hae Ok; Kim, Gyo-Nam; Song, Ji-Hye

2015-01-01

319

Effect of altering endogenous gonadotrophin concentrations on the kinetics of testicular germ cell turnover in the bonnet monkey (Macaca radiata).  

PubMed

The role of FSH and diurnal testosterone rhythms in specific germ cell transformations during spermatogenesis were investigated using DNA flow cytometry and morphometry of the seminiferous epithelium of the adult male bonnet monkey (Macaca radiata), the endogenous hormone levels of which were altered by two different protocols. (1) Active immunization of five monkeys for 290 days using ovine FSH adsorbed on Alhydrogel resulted in the neutralization of endogenous FSH, leaving the LH and diurnal testosterone rhythms normal. (2) Desensitization of the pituitary gonadotrophs of ten monkeys by chronically infusing gonadotrophin-releasing hormone analogue, buserelin (50 micrograms/day release rate), via an Alzet pump implant (s.c.) led to a 60-80% reduction in LH and FSH as well as total abolition of testosterone rhythms. The basal testosterone level (3.3 +/- 2.0 micrograms/l), however, was maintained in this group by way of an s.c. testosterone silicone elastomer implant. Both of the treatments caused significant (P < 0.01) nearly identical reduction in testicular biopsy scores, mitotic indices and daily sperm production rates compared with respective controls. The germ cell DNA flow cytometric profiles of the two treatment groups, however, were fundamentally different from each other. The pituitary-desensitized group exhibited a significant (P < 0.001) increase in 2C (spermatogonial) and decrease in 1C (round spermatid) populations while S-phase (preleptotene spermatocytes) and 4C (primary spermatocytes) populations were normal, indicating an arrest in meiosis caused presumably by the lack of increment in nocturnal serum testosterone. In contrast, in the FSH-immunized group, at day 80 when the FSH deprivation was total, the primary block appeared to be at the conversion of spermatogonia (2C) to cells in S-phase and primary spermatocytes (4C reduced by > 90%). In addition, at this time, although the round spermatid (1C) population was reduced by 65% (P < 0.01) the elongate spermatid (HC) population showed an increase of 52% (P < 0.05). This, taken together with the fact that sperm output in the ejaculate is reduced by 80%, suggests a blockade in spermiogenesis and spermiation. Administration of booster injections of oFSH at time-points at which the antibody titre was markedly low (at days 84 and 180) resulted in a transient resurgence in spermatogenesis (at day 180 and 228), and this again was blocked by day 290 when the FSH antibody titre increased.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8371078

Aravindan, G R; Gopalakrishnan, K; Ravindranath, N; Moudgal, N R

1993-06-01

320

Endogenous DNA Damage and Risk of Testicular Germ Cell Tumors  

SciTech Connect

Testicular germ cell tumors (TGCT) are comprised of two histologic groups, seminomas and nonseminomas. We postulated that the possible divergent pathogeneses of these histologies may be partially explained by variable endogenous DNA damage. To assess our hypothesis, we conducted a case-case analysis of seminomas and nonseminomas using the alkaline comet assay to quantify single-strand DNA breaks and alkali-labile sites. The Familial Testicular Cancer study and the U.S. Radiologic Technologists cohort provided 112 TGCT cases (51 seminomas & 61 nonseminomas). A lymphoblastoid cell line was cultured for each patient and the alkaline comet assay was used to determine four parameters: tail DNA, tail length, comet distributed moment (CDM) and Olive tail moment (OTM). Odds ratios (OR) and 95% confidence intervals (95%CI) were estimated using logistic regression. Values for tail length, tail DNA, CDM and OTM were modeled as categorical variables using the 50th and 75th percentiles of the seminoma group. Tail DNA was significantly associated with nonseminoma compared to seminoma (OR{sub 50th percentile} = 3.31, 95%CI: 1.00, 10.98; OR{sub 75th percentile} = 3.71, 95%CI: 1.04, 13.20; p for trend=0.039). OTM exhibited similar, albeit statistically non-significant, risk estimates (OR{sub 50th percentile} = 2.27, 95%CI: 0.75, 6.87; OR{sub 75th percentile} = 2.40, 95%CI: 0.75, 7.71; p for trend=0.12) whereas tail length and CDM showed no association. In conclusion, the results for tail DNA and OTM indicate that endogenous DNA damage levels are higher in patients who develop nonseminoma compared with seminoma. This may partly explain the more aggressive biology and younger age-of-onset of this histologic subgroup compared with the relatively less aggressive, later-onset seminoma.

Cook, M B; Sigurdson, A J; Jones, I M; Thomas, C B; Graubard, B I; Korde, L; Greene, M H; McGlynn, K A

2008-01-18

321

Distinct germ line polymorphisms underlie glioma morphologic heterogeneity.  

PubMed

Two recent genome-wide association studies reported that single nucleotide polymorphisms (SNPs) in (or near) TERT (5p15), CCDC26 (8q24), CDKN2A/B (9p21), PHLDB1 (11q23), and RTEL1 (20q13) are associated with infiltrating glioma. From these reports, it was not clear whether the single nucleotide polymorphism associations predispose to glioma in general or whether they are specific to certain glioma grades or morphologic subtypes. To identify hypothesized associations between susceptibility loci and tumor subtype, we genotyped two case-control groups composed of the spectrum of infiltrating glioma subtypes and stratified the analyses by type. We report that specific germ line polymorphisms are associated with different glioma subtypes. CCDC26 (8q24) region polymorphisms are strongly associated with oligodendroglial tumor risk (rs4295627, odds ratio [OR] = 2.05, P = 8.3 × 10(-11)) but not glioblastoma risk. The opposite is true of RTEL (20q13) region polymorphisms, which are significantly associated with glioblastoma (rs2297440, OR = 0.56, P = 4.6 × 10(-10)) but not oligodendroglial tumor. The SNPs in or near CCDC26 (8q24) are associated with oligodendroglial tumors regardless of combined 1p and 19q deletion status; however, the association is greatest for those with combined deletion (rs4295627, OR = 2.77, P = 2.6 × 10(-9)). These observations generate hypotheses concerning the possible mechanisms by which specific SNPs (or alterations in linkage disequilibrium with such SNPs) are associated with glioma development. PMID:21356187

Jenkins, Robert B; Wrensch, Margaret R; Johnson, Derek; Fridley, Brooke L; Decker, Paul A; Xiao, Yuanyuan; Kollmeyer, Thomas M; Rynearson, Amanda L; Fink, Stephanie; Rice, Terri; McCoy, Lucie S; Halder, Chandralekha; Kosel, Matthew L; Giannini, Caterina; Tihan, Tarik; O'Neill, Brian P; Lachance, Daniel H; Yang, Ping; Wiemels, Joseph; Wiencke, John K

2011-01-01

322

Amenorrhea - primary  

MedlinePLUS

... signs of puberty. Being born with incompletely formed genital or pelvic organs can lead to primary amenorrhea. ... the following conditions: Congenital defects of the upper genital system (uterus, hymen, and other structures inside the ...

323

Primary Myelofibrosis  

MedlinePLUS

... a disease in which abnormal blood cells and fibers build up inside the bone marrow. The bone ... blood cells , and platelets ) and a web of fibers that support the blood-forming tissues. In primary ...

324

Primary Hyperparathyroidism  

MedlinePLUS

... of calcium into the blood, causing blood calcium levels to rise above normal. The loss of calcium from bones ... that leads to dehydration can cause blood calcium levels to rise further in someone with primary hyperparathyroidism. People with ...

325

Primary cystic peritoneal masses and mimickers: spectrum of diseases with pathologic correlation.  

PubMed

Cystic lesions within the peritoneum have been classified classically according to their lining on histology into four categories-endothelial, epithelial, mesothelial, and others (germ cell tumors, sex cord gonadal stromal tumors, cystic mesenchymal tumors, fibrous wall tumors, and infectious cystic peritoneal lesions). In this article, we will proceed to classify cystic peritoneal lesions focusing on the degree of radiological complexity into three categories-simple cystic, mildly complex, and cystic with solid component lesions. Many intra-abdominal collections within the peritoneal cavity such as abscess, seroma, biloma, urinoma, or lymphocele may mimic primary peritoneal cystic masses and need to be differentiated. Clinical history and imaging features may help differentiate intra-abdominal collections from primary peritoneal masses. Lymphangiomas are benign multilocular cystic masses that can virtually occur in any location within the abdomen and insinuate between structures. Ultrasound may help differentiate enteric duplication cysts from other mesenteric and omental cysts in the abdomen. Double-layered wall along the mesenteric side of bowel may suggest its diagnosis in the proper clinical setting. Characteristic imaging features of hydatid cysts are internal daughter cysts, floating membranes and matrix, peripheral calcifications, and collagenous pericyst. Non-pancreatic psuedocysts usually have a fibrotic thick wall and chylous content may lead to a fat-fluid level. Pseudomyxoma peritonei appears as loculated fluid collections in the peritoneal cavity, omentum, and mesentery and may scallop visceral surfaces. Many of the primary cystic peritoneal masses have specific imaging features which can help in accurate diagnosis and management of these entities. Knowledge of the imaging spectrum of cystic peritoneal masses is necessary to distinguish from other potential cystic abdominal mimicker masses. PMID:25269999

Arraiza, María; Metser, Ur; Vajpeyi, Rajkumar; Khalili, Korosh; Hanbidge, Anthony; Kennedy, Erin; Ghai, Sangeet

2015-04-01

326

Exogenous supplementation of Activin A enhances germ cell differentiation of human embryonic stem cells†.  

PubMed

Human embryonic stem cells (hESCs) derived in the presence of Activin A (ActA) demonstrate an increased differentiation propensity toward the germ cell lineage. In addition, mouse epiblast stem cells and mouse epiblast-like cells are poised toward germ cell differentiation and are derived in the presence of ActA. We therefore investigated whether supplementation with ActA enhances in vitro hESC differentiation toward germ cell lineage. ActA up-regulated early primordial germ cell (PGC) genes STELLA/DPPA3 (developmental pluripotency associated 3) and tyrosine kinase receptor cKIT in both ActA-derived and standard-derived hESCs indicating its role in priming hESCs toward the PGC lineage. Indeed, ActA plus bone morphogenic protein 4 (BMP4) strongly increased germ cell differentiation potential of hESCs based on the high expression of late PGC markers DAZL (deleted in azoospermia-like) and VASA/DDX4 (DEAD-box polypeptide 4) at mRNA and protein level. Hence, the combination of ActA with BMP4 provides an additional boost for hESCs to develop into postmigratory germ cells. Together with increased VASA expression in the presence of ActA and BMP4, we also observed up-regulation of endoderm-specific genes GATA4 (GATA binding protein 4) and GATA6. Finally, we were able to further mature these in vitro-derived PGC-like cells (PGCLCs) by culturing them in in vitro maturation (IVM) medium, resulting in the formation of germ cell-like clusters and induction of meiotic gene expression. In conclusion, we demonstrate for the first time a synergism between ActA and BMP4 in facilitating germ cell-directed differentiation of hESCs, which is enhanced by extended culture in IVM medium, as shown by cytoplasmic VASA-expressing PGCLCs. We propose a novel relationship between the endoderm and germ cell lineage during hESC differentiation. PMID:25634576

Duggal, Galbha; Heindryckx, Björn; Warrier, Sharat; Taelman, Jasin; Van der Jeught, Margot; Deforce, Dieter; Chuva de Sousa Lopes, Susana; De Sutter, Petra

2015-05-01

327

Gender differences in the induction of chromosomal aberrations and gene mutations in rodent germ cells  

SciTech Connect

Germ cell mutagenicity testing provides experimental data to quantify genetic risk for exposed human populations. The majority of tests are performed with exposure of males, and female data are relatively rare. The reason for this paucity lies in the differences between male and female germ cell biology. Male germ cells are produced throughout reproductive life and all developmental stages can be ascertained by appropriate breeding schemes. In contrast, the female germ cell pool is limited, meiosis begins during embryogenesis and oocytes are arrested over long periods of time until maturation processes start for small numbers of oocytes during the oestrus cycle in mature females. The literature data are reviewed to point out possible gender differences of germ cells to exogenous agents such as chemicals or ionizing radiation. From the limited information, it can be concluded that male germ cells are more sensitive than female germ cells to the induction of chromosomal aberrations and gene mutations. However, exceptions are described which shed doubt on the extrapolation of experimental data from male rodents to the genetic risk of the human population. Furthermore, the female genome may be more sensitive to mutation induction during peri-conceptional stages compared to the male genome of the zygote. With few exceptions, germ cell experiments have been carried out under high acute exposure to optimize the effects and to compensate for the limited sample size in animal experiments. Human exposure to environmental agents, on the other hand, is usually chronic and involves low doses. Under these conditions, gender differences may become apparent that have not been studied so far. Additionally, data are reviewed that suggest a false impression of safety when responses are negative under high acute exposure of male rodents while a mutational response is induced by low chronic exposure. The classical (morphological) germ cell mutation tests are not performed anymore because they are animal and time consuming. Nevertheless, information is needed to place genetic risk extrapolations on more solid grounds and thereby to prevent an increased genetic burden to future generations. It is pointed out that modern molecular methodologies are available now to experimentally address the open questions.

Adler, Ilse-Dore [GSF-Institute of Experimental Genetics, Neuherberg D-85758 (Germany); Carere, Angelo [Istituto Superiore di Sanita, Viale Regina Elena 299, Rome 00161 (Italy); Eichenlaub-Ritter, Ursula [Institute of Genetechnology/Microbiology, University of Bielefeld, Bielefeld D-33501 (Germany)]. E-mail: EiRi@uni-bielefeld.de; Pacchierotti, Francesca [Section of Toxicology and Biomedical Sciences, ENEA, CR Casaccia, Via Anguillarese 301, Rome 00060 (Italy)

2007-05-15

328

Licensing of primordial germ cells for gametogenesis depends on genital ridge signaling.  

PubMed

In mouse embryos at mid-gestation, primordial germ cells (PGCs) undergo licensing to become gametogenesis-competent cells (GCCs), gaining the capacity for meiotic initiation and sexual differentiation. GCCs then initiate either oogenesis or spermatogenesis in response to gonadal cues. Germ cell licensing has been considered to be a cell-autonomous and gonad-independent event, based on observations that some PGCs, having migrated not to the gonad but to the adrenal gland, nonetheless enter meiosis in a time frame parallel to ovarian germ cells -- and do so regardless of the sex of the embryo. Here we test the hypothesis that germ cell licensing is cell-autonomous by examining the fate of PGCs in Gata4 conditional mutant (Gata4 cKO) mouse embryos. Gata4, which is expressed only in somatic cells, is known to be required for genital ridge initiation. PGCs in Gata4 cKO mutants migrated to the area where the genital ridge, the precursor of the gonad, would ordinarily be formed. However, these germ cells did not undergo licensing and instead retained characteristics of PGCs. Our results indicate that licensing is not purely cell-autonomous but is induced by the somatic genital ridge. PMID:25739037

Hu, Yueh-Chiang; Nicholls, Peter K; Soh, Y Q Shirleen; Daniele, Joseph R; Junker, Jan Philipp; van Oudenaarden, Alexander; Page, David C

2015-03-01

329

TOPAZ1, a Novel Germ Cell-Specific Expressed Gene Conserved during Evolution across Vertebrates  

PubMed Central

Background We had previously reported that the Suppression Subtractive Hybridization (SSH) approach was relevant for the isolation of new mammalian genes involved in oogenesis and early follicle development. Some of these transcripts might be potential new oocyte and granulosa cell markers. We have now characterized one of them, named TOPAZ1 for the Testis and Ovary-specific PAZ domain gene. Principal Findings Sheep and mouse TOPAZ1 mRNA have 4,803 bp and 4,962 bp open reading frames (20 exons), respectively, and encode putative TOPAZ1 proteins containing 1,600 and 1653 amino acids. They possess PAZ and CCCH domains. In sheep, TOPAZ1 mRNA is preferentially expressed in females during fetal life with a peak during prophase I of meiosis, and in males during adulthood. In the mouse, Topaz1 is a germ cell-specific gene. TOPAZ1 protein is highly conserved in vertebrates and specifically expressed in mouse and sheep gonads. It is localized in the cytoplasm of germ cells from the sheep fetal ovary and mouse adult testis. Conclusions We have identified a novel PAZ-domain protein that is abundantly expressed in the gonads during germ cell meiosis. The expression pattern of TOPAZ1, and its high degree of conservation, suggests that it may play an important role in germ cell development. Further characterization of TOPAZ1 may elucidate the mechanisms involved in gametogenesis, and particularly in the RNA silencing process in the germ line. PMID:22069478

Baillet, Adrienne; Le Bouffant, Ronan; Volff, Jean Nicolas; Luangpraseuth, Alix; Poumerol, Elodie; Thépot, Dominique; Pailhoux, Eric; Livera, Gabriel; Cotinot, Corinne; Mandon-Pépin, Béatrice

2011-01-01

330

Dodonaea viscosa var. angustifolia Inhibits Germ Tube and Biofilm Formation by C. albicans  

PubMed Central

The virulence factors of Candida albicans are germ tube and biofilm formation, adherence to host tissues, and production of hydrolytic enzymes. This study investigated the effect of Dodonaea viscosa var. angustifolia extract on the germ tube and biofilm formation of C. albicans. Serum containing the three subinhibitory concentrations of leaf extract was inoculated with C. albicans, incubated, and viewed under a light microscope. Number of cells with germ tube was recorded and the results were analysed using Scheffe test for pairwise comparison. Biofilms were grown on coverslips in the presence of plant extracts and processed for scanning electron microscopy (SEM). Planktonic cells were grown in the presence of plant extract for 6?h and processed for electron microscopy (TEM). The crude plant extract significantly (P < 0.01) reduced the germ tube formation of C. albicans at 3.125 (85.36%), 1.56 (61.91%), and 0.78?mg/mL (26.27%) showing a concentration dependent effect. SEM results showed concentration dependent reduction in biofilm and hyphae formation. TEM results showed that the plant extract caused damage to the cell wall and cell membrane. DVA extract has ability to reduce virulence of C. albicans by inhibiting germ tube and biofilm formation through damage to the cell wall. Therefore, it has therapeutic potential. PMID:24223612

Naicker, Serisha Devi

2013-01-01

331

P granules extend the nuclear pore complex environment in the C. elegans germ line  

PubMed Central

The immortal and totipotent properties of the germ line depend on determinants within the germ plasm. A common characteristic of germ plasm across phyla is the presence of germ granules, including P granules in Caenorhabditis elegans, which are typically associated with the nuclear periphery. In C. elegans, nuclear pore complex (NPC)–like FG repeat domains are found in the VASA-related P-granule proteins GLH-1, GLH-2, and GLH-4 and other P-granule components. We demonstrate that P granules, like NPCs, are held together by weak hydrophobic interactions and establish a size-exclusion barrier. Our analysis of intestine-expressed proteins revealed that GLH-1 and its FG domain are not sufficient to form granules, but require factors like PGL-1 to nucleate the localized concentration of GLH proteins. GLH-1 is necessary but not sufficient for the perinuclear location of granules in the intestine. Our results suggest that P granules extend the NPC environment in the germ line and provide insights into the roles of the PGL and GLH family proteins. PMID:21402789

Updike, Dustin L.; Hachey, Stephanie J.; Kreher, Jeremy

2011-01-01

332

Dispensability of nanos mRNA localization for abdominal patterning but not for germ cell development  

PubMed Central

Summary The development of a functional germline is essential for species propagation. The nanos (nos) gene plays an evolutionarily conserved role in germline development and is also essential for abdominal patterning in Drosophila. A small fraction of nos mRNA is localized to the germ plasm at the posterior pole of the Drosophila embryo, where it becomes incorporated into the germ cells. Germ plasm associated nos mRNA is translated to produce a gradient of Nos protein that patterns the abdomen, whereas the remaining unlocalized RNA is translationally repressed to allow anterior development. Using transgenes that compromise nos mRNA localization and translational regulation, we show wild-type body patterning can ensue without nos mRNA localization provided that nos translation is properly modulated. In contrast, localization of nos to the germ plasm, but not translational regulation, is essential for nos function in the developing germ cells. We propose that an imperative for nos localization in producing a functional germline has preserved an inefficient localization mechanism. PMID:18036786

Gavis, Elizabeth R.; Chatterjee, Seema; Ford, Nicole R.; Wolff, Lisa J.

2008-01-01

333

Licensing of Primordial Germ Cells for Gametogenesis Depends on Genital Ridge Signaling  

PubMed Central

In mouse embryos at mid-gestation, primordial germ cells (PGCs) undergo licensing to become gametogenesis-competent cells (GCCs), gaining the capacity for meiotic initiation and sexual differentiation. GCCs then initiate either oogenesis or spermatogenesis in response to gonadal cues. Germ cell licensing has been considered to be a cell-autonomous and gonad-independent event, based on observations that some PGCs, having migrated not to the gonad but to the adrenal gland, nonetheless enter meiosis in a time frame parallel to ovarian germ cells -- and do so regardless of the sex of the embryo. Here we test the hypothesis that germ cell licensing is cell-autonomous by examining the fate of PGCs in Gata4 conditional mutant (Gata4 cKO) mouse embryos. Gata4, which is expressed only in somatic cells, is known to be required for genital ridge initiation. PGCs in Gata4 cKO mutants migrated to the area where the genital ridge, the precursor of the gonad, would ordinarily be formed. However, these germ cells did not undergo licensing and instead retained characteristics of PGCs. Our results indicate that licensing is not purely cell-autonomous but is induced by the somatic genital ridge. PMID:25739037

Hu, Yueh-Chiang; Nicholls, Peter K.; Soh, Y. Q. Shirleen; Daniele, Joseph R.; Junker, Jan Philipp; van Oudenaarden, Alexander; Page, David C.

2015-01-01

334

Expression pattern of clinically relevant markers in paediatric germ cell- and sex-cord stromal tumours is similar to adult testicular tumours.  

PubMed

Paediatric germ cell tumours (GCTs) are rare and account for less than 3 % of childhood cancers. Like adult GCTs, they probably originate from primordial germ cells, but the pattern of histopathological types is different, and they occur predominantly in extragonadal sites along the body midline. Because they are rare, histology of paediatric GCTs is poorly documented, and it remains unclear to what extent they differ from adult GCTs. We have analysed 35 paediatric germ cell tumours and 5 gonadal sex-cord stromal tumours from prepubertal patients aged 0-15 years, to gain further knowledge, elaborate on clinical-pathological associations and better understand their developmental divergence. The tumours were screened for expression of stemness-related factors (OCT4, AP-2?, SOX2), classical yolk sac tumours (YSTs; AFP, SALL4), GCTs (HCG, PLAP, PDPN/D2-40), as well as markers for sex-cord stromal tumour (PDPN, GATA4). All YSTs expressed AFP and SALL4, with GATA4 present in 13/14. The majority of teratomas expressed SOX2 and PDPN, whereas SALL4 was found in 8/13 immature teratomas. Adult seminoma markers AP-2?, OCT4, SALL4 and PDPN were all expressed in dysgerminoma. We further report a previously unrecognised pathogenetic relationship between AFP and SALL4 in YST in that different populations of YST cells express either SALL4 or AFP, which suggests variable differentiation status. We also show that AP-2? is expressed in the granulosa layer of ovarian follicles and weakly expressed in immature but not in mature granulosa cell tumours. Our findings indicate that the expression pattern of these antigens is similar between paediatric and adult GCTs, even though they develop along different developmental trajectories. PMID:25074678

Mosbech, Christiane Hammershaimb; Svingen, Terje; Nielsen, John Erik; Toft, Birgitte Groenkaer; Rechnitzer, Catherine; Petersen, Bodil Laub; Rajpert-De Meyts, Ewa; Hoei-Hansen, Christina Engel

2014-11-01

335

Genome Analysis of Elysia chlorotica Egg DNA Provides No Evidence for Horizontal Gene Transfer into the Germ Line of This Kleptoplastic Mollusc  

PubMed Central

The sea slug Elysia chlorotica offers a unique opportunity to study the evolution of a novel function (photosynthesis) in a complex multicellular host. Elysia chlorotica harvests plastids (absent of nuclei) from its heterokont algal prey, Vaucheria litorea. The “stolen” plastids are maintained for several months in cells of the digestive tract and are essential for animal development. The basis of long-term maintenance of photosynthesis in this sea slug was thought to be explained by extensive horizontal gene transfer (HGT) from the nucleus of the alga to the animal nucleus, followed by expression of algal genes in the gut to provide essential plastid-destined proteins. Early studies of target genes and proteins supported the HGT hypothesis, but more recent genome-wide data provide conflicting results. Here, we generated significant genome data from the E. chlorotica germ line (egg DNA) and from V. litorea to test the HGT hypothesis. Our comprehensive analyses fail to provide evidence for alga-derived HGT into the germ line of the sea slug. Polymerase chain reaction analyses of genomic DNA and cDNA from different individual E. chlorotica suggest, however, that algal nuclear genes (or gene fragments) are present in the adult slug. We suggest that these nucleic acids may derive from and/or reside in extrachromosomal DNAs that are made available to the animal through contact with the alga. These data resolve a long-standing issue and suggest that HGT is not the primary reason underlying long-term maintenance of photosynthesis in E. chlorotica. Therefore, sea slug photosynthesis is sustained in as yet unexplained ways that do not appear to endanger the animal germ line through the introduction of dozens of foreign genes. PMID:23645554

Bhattacharya, Debashish; Pelletreau, Karen N.; Price, Dana C.; Sarver, Kara E.; Rumpho, Mary E.

2013-01-01

336

Genome analysis of Elysia chlorotica Egg DNA provides no evidence for horizontal gene transfer into the germ line of this Kleptoplastic Mollusc.  

PubMed

The sea slug Elysia chlorotica offers a unique opportunity to study the evolution of a novel function (photosynthesis) in a complex multicellular host. Elysia chlorotica harvests plastids (absent of nuclei) from its heterokont algal prey, Vaucheria litorea. The "stolen" plastids are maintained for several months in cells of the digestive tract and are essential for animal development. The basis of long-term maintenance of photosynthesis in this sea slug was thought to be explained by extensive horizontal gene transfer (HGT) from the nucleus of the alga to the animal nucleus, followed by expression of algal genes in the gut to provide essential plastid-destined proteins. Early studies of target genes and proteins supported the HGT hypothesis, but more recent genome-wide data provide conflicting results. Here, we generated significant genome data from the E. chlorotica germ line (egg DNA) and from V. litorea to test the HGT hypothesis. Our comprehensive analyses fail to provide evidence for alga-derived HGT into the germ line of the sea slug. Polymerase chain reaction analyses of genomic DNA and cDNA from different individual E. chlorotica suggest, however, that algal nuclear genes (or gene fragments) are present in the adult slug. We suggest that these nucleic acids may derive from and/or reside in extrachromosomal DNAs that are made available to the animal through contact with the alga. These data resolve a long-standing issue and suggest that HGT is not the primary reason underlying long-term maintenance of photosynthesis in E. chlorotica. Therefore, sea slug photosynthesis is sustained in as yet unexplained ways that do not appear to endanger the animal germ line through the introduction of dozens of foreign genes. PMID:23645554

Bhattacharya, Debashish; Pelletreau, Karen N; Price, Dana C; Sarver, Kara E; Rumpho, Mary E

2013-08-01

337

Proteasome regulation of the chromodomain protein MRG-1 controls the balance between proliferative fate and differentiation in the C. elegans germ line.  

PubMed

The level of stem cell proliferation must be tightly controlled for proper development and tissue homeostasis. Multiple levels of gene regulation are often employed to regulate stem cell proliferation to ensure that the amount of proliferation is aligned with the needs of the tissue. Here we focus on proteasome-mediated protein degradation as a means of regulating the activities of proteins involved in controlling the stem cell proliferative fate in the C. elegans germ line. We identify five potential E3 ubiquitin ligases, including the RFP-1 RING finger protein, as being involved in regulating proliferative fate. RFP-1 binds to MRG-1, a homologue of the mammalian chromodomain-containing protein MRG15 (MORF4L1), which has been implicated in promoting the proliferation of neural precursor cells. We find that C. elegans with reduced proteasome activity, or that lack RFP-1 expression, have increased levels of MRG-1 and a shift towards increased proliferation in sensitized genetic backgrounds. Likewise, reduction of MRG-1 partially suppresses stem cell overproliferation. MRG-1 levels are controlled independently of the spatially regulated GLP-1/Notch signalling pathway, which is the primary signal controlling the extent of stem cell proliferation in the C. elegans germ line. We propose a model in which MRG-1 levels are controlled, at least in part, by the proteasome, and that the levels of MRG-1 set a threshold upon which other spatially regulated factors act in order to control the balance between the proliferative fate and differentiation in the C. elegans germ line. PMID:25564623

Gupta, Pratyush; Leahul, Lindsay; Wang, Xin; Wang, Chris; Bakos, Brendan; Jasper, Katie; Hansen, Dave

2015-01-15

338

Establishment and Characterization of a new Human Extragonadal Germ Cell Line, SEM-1, and its Comparison With TCam-2 and JKT-1  

PubMed Central

OBJECTIVE To describe the establishment and characterization of a human cell line, SEM-1, from a patient diagnosed with a mediastinal seminoma. METHODS A small percentage of germ cell tumors develop as primary lesions in extragonadal sites, and the etiology of these tumors is poorly understood. Currently, only 2 cell lines from seminoma patients have been reported, JKT-1 and TCam-2, both derived from the testis. The cell line was characterized by heterotransplantation in Nude mice, cytogenetic studies, immunohistochemical and flow cytometry staining for germ cell tumor biomarkers, quantitative reverse-transcription polymerase chain reaction for cancer testis antigen expression, and BRAF mutation screening with quantitative polymerase chain reaction. RESULTS Characterization studies confirmed the human extragonadal seminoma origin of SEM-1 and demonstrated that it had more features in common with TCam-2 than JKT-1. Specifically, SEM-1 was positive for Sal-like protein 4 (SALL-4), activator protein-2? (AP-2?), and cytokeratin CAM5.2, and demonstrated heterogeneous expression of stem cell markers octamer-binding transcription factor 3/4, NANOG, c-KIT, SOX17, and SOX2. Cytogenetic analysis revealed a hypotriploid chromosome number, with multiple copies of 12p, but isochromosome 12p and the BRAF mutation V600E were not identified. The cell lines also did not contain the BRD4/NUT gene rearrangement [t(15,19)] seen in midline carcinomas nor did they contain overexpressed nuclear protein in testis (NUT) genes. CONCLUSION SEM-1 is the first cell line derived from an extragonadal germ cell tumor showing intermediate characteristics between seminoma and nonseminoma, and as such, is an important model to study the molecular pathogenesis of this malignancy. PMID:23374840

Russell, Sarah M.; Lechner, Melissa G.; Mokashi, Anusuya; Megiel, Carolina; Jang, Julie K.; Taylor, Clive R.; Looijenga, Leendert H.J.; French, Christopher A.; Epstein, Alan L.

2014-01-01

339

Retention of ingested latex particles in Peyer's patches of germ-free and conventional mice  

SciTech Connect

Conventional and germ-free mice ingested a suspension of 2-..mu..m latex particles in drinking water for a 15-day period. Number and distribution of intestinal Peyer's patches did not differ significantly in the two types of mice. Cleared Peyer's patches were compared with regard to size and particle content. The location of particles within Peyer's patch follicles of germ-free mice was similar to that of conventional mice, but the latter had significantly larger follicles and greater accumulations of latex particles. Latex concentration varied with patch location. Proximal patches contained the majority of particles in germ-free mice, whereas particles were most abundant in distal patches of conventional mice. The results show that particle uptake into Peyer's patches takes place even in the complete absence of bacteria in the gut.

Lefevre, M.E.; Joel, D.D.; Schidlovsky, G.

1985-09-01

340

[Intracranial germ cell tumors: the point of view of the endocrinologist].  

PubMed

Extragonadal germ cell tumors are rare neoplasms most commonly diagnosed in the first and second decades of life. Intracranially they tend to arise in the midline in the pineal and hypothalamic/intrasellar regions. The clinical presentation in the central nervous system depends on the patient's age, tumor location, and tumor size. Because of the proximity of these tumors to the hypothalamus and pituitary gland, their presence often results in the development of various hormonal abnormalities. Patients most often present with diabetes insipidus, growth hormone insufficiency and precocious puberty. Early diagnosis of germ cell tumors is of the utmost importance as they are highly radiosensitive, although the correct diagnosis may be sometimes difficult to achieve. In this paper, we review different aspects of pathology, clinical presentation, diagnosis and management of intracranial germ cell tumors. Particular attention is paid to the endocrine aspects of these tumors. PMID:24697039

Krysiak, Robert

2013-01-01

341

An ABC transporter controls export of a Drosophila germ cell attractant.  

PubMed

Directed cell migration, which is critical for embryonic development, leukocyte trafficking, and cell metastasis, depends on chemoattraction. 3-hydroxy-3-methylglutaryl coenzyme A reductase regulates the production of an attractant for Drosophila germ cells that may itself be geranylated. Chemoattractants are commonly secreted through a classical, signal peptide-dependent pathway, but a geranyl-modified attractant would require an alternative pathway. In budding yeast, pheromones produced by a-cells are farnesylated and secreted in a signal peptide-independent manner, requiring the adenosine triphosphate-binding cassette (ABC) transporter Ste6p. Here we show that Drosophila germ cell migration uses a similar pathway, demonstrating that invertebrate germ cells, like yeast cells, are attracted to lipid-modified peptides. Components of this unconventional export pathway are highly conserved, suggesting that this pathway may control the production of similarly modified chemoattractants in organisms ranging from yeast to humans. PMID:19213920

Ricardo, Sara; Lehmann, Ruth

2009-02-13

342

Classification and pathology of testicular germ cell and sex cord-stromal tumors.  

PubMed

Germ cell tumors of the testis are the most frequent testicular neoplasms, with seminoma predominating. The pathologist must be able to discriminate between seminoma and nonseminomatous germ cell tumors as well as sex cord-stromal tumors and metastatic lesions. Appropriate therapy and accurate prognostic information are dependent on the proper classification of testicular neoplasia. Characteristic histologic features, serum markers, and immunohistochemistry are helpful in this regard. Sex cord-stromal tumors comprise a small minority of testicular neoplasms. It remains critically important not to confuse these neoplasms with testicular germ cell or metastatic tumors, and, again, recognition of the characteristic histologic features, immunohistochemical findings, and clinical information is diagnostic. The urologist can provide the pathologist with key clinical information in the attempt to make a correct diagnosis. PMID:10494291

Cheville, J C

1999-08-01

343

Metastable primordial germ cell-like state induced from mouse embryonic stem cells by Akt activation  

SciTech Connect

Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, indicating that the sphere cells had commenced differentiation to the germ lineage. However, the spheres did not proceed to spermatogenesis after transplantation into testes. Sphere cell transfer to the original feeder-free ESC cultures resulted in chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, reversion to the ESC-like state was observed. These results indicate that Akt signaling promotes a novel metastable and pluripotent state that is intermediate to those of ESCs and PGCs.

Yamano, Noriko [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Kimura, Tohru, E-mail: tkimura@patho.med.osaka-u.ac.jp [Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Watanabe-Kushima, Shoko [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)] [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Shinohara, Takashi [Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501 (Japan)] [Department of Molecular Genetics, Graduate School of Medicine, Kyoto University, Kyoto 606-8501 (Japan); Nakano, Toru, E-mail: tnakano@patho.med.osaka-u.ac.jp [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan) [Graduate School of Frontier Biosciences, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan); Department of Pathology, Medical School, Osaka University, 2-2 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2010-02-12

344

Earth's Layers  

NSDL National Science Digital Library

Complete a poster all about Earth's Layers! Directions: Make a poster about Earth's Layers. (20 points) Include at least (1) large picture (15 points) on your poster complete with labels of every part (10 points). (15 points) Include at least three (3) facts about Earth's Layers. (5 points each) (15 points) Write at least a three sentence summary of your poster ...

Mrs. Walls

2011-01-30

345

Cisplatin resistance in germ cell tumours: models and mechanisms.  

PubMed

Recent years have led to a better understanding of the mechanisms underlying cisplatin response and resistance in germ cell tumours (GCT), and several promising targets have been identified. Two main mechanisms of the responsiveness to DNA damaging agents have been postulated. Firstly, GCT readily activate a DNA damage response, but show deficits in several damage repair pathways. In particular, they have been found to have defects in interstrand crosslink repair and in homologous recombination (HR). Secondly, GCT, especially embryonal carcinoma (EC) cells, show a hypersensitive apoptotic response to DNA damage, which activates p53, and leads to up-regulation of the pro-apoptotic factors Noxa, Puma and Fas in non-resistant EC. These cells fail to activate p21 which induces a G1/S arrest, but accumulate in G2/M phase. In the absence of functional p53, family members like p73 and GTAp63 might be important in initiating this response. Mechanisms involved in cisplatin resistance are as follows: down-regulation of Oct4 (e.g. as a result of hypoxia, treatment with retinoic acid or exposure to cisplatin) and failure to induce Puma and Noxa; changes in the expression levels of micro-RNAs such as miR-17/-106b, miR-302a, or miR-371 to -373; elevated levels of MDM2 and cytoplasmic translocation of p21 by phosphorylation; and activation of the PDGFR?/PI3K/pAKT pathway. Several approaches to overcome resistance have been successfully examined in vitro and in vivo, including PARP inhibitors, especially in cells showing deficient HR-repair; stabilization of p53 using nutlin-3; inhibition of several components of the PI3K/pAKT pathway using small molecules; and DNA demethylation by 5-azacytidine or 5-aza-deoxy-cytidine, among others. Many of these substances deserve further exploration, alone or in combination with DNA damaging agents, and the most promising approaches should be taken forward to clinical testing. Targeted therapy based on mechanistic insights holds the promise to turn cisplatin-resistant GCT into a curable disease. PMID:25546083

Jacobsen, C; Honecker, F

2015-01-01

346

Evaluation of pharmacokinetic differences of acetaminophen in pseudo germ-free rats.  

PubMed

To evaluate the metabolic interaction between host and gut microflora on drug metabolism, pseudo germ-free rats were prepared with an antibiotics cocktail to change their gut conditions. The usefulness of the pseudo germ-free model was evaluated for observing the DMPK of acetaminophen (APAP). Pseudo germ-free rats were prepared by orally administering antibiotic cocktails consisting of bacitracin, streptomycin and neomycin, and then APAP was orally administered to control and pseudo germ-free rats. The plasma concentration of APAP and its six metabolites were quantified using a validated LC-MS/MS method. A non-compartment model estimated the pharmacokinetic parameters of APAP and its metabolites, and the ratios of the area under curve (AUC; AUC(metabolite) /AUC(APAP) ) were also observed to evaluate the change of APAP metabolism. The AUCs of APAP and APAP-Glth (glutathione) were higher and the AUC(APAP-Sul) /AUC(APAP) (metabolic efficiency of sulfate conjugation) was lower in pseudo germ-free rats than those in the control rats. The decrease in metabolic efficiency of sulphate conjugation could result from the reduction of the sulphate supply, causing an increase of the AUC of APAP and APAP-Glth. The activities of gut microflora can affect the state of hepatic sulphate for drug conjugation, indirectly leading to characteristic APAP metabolism. These results indicate that gut microflora may play an important role in the pharmacokinetics and metabolism of APAP. Thus, the metabolic interaction between host and gut microflora should be considered upon drug administration and pseudo germ-free rats prepared in the present study can be competent for investigating the metabolic interaction between host and gut microflora on drug metabolism. PMID:22806334

Lee, Soo Hyun; An, Ji Hye; Lee, Hwa Jeong; Jung, Byung Hwa

2012-09-01

347

Germ cells: a new source of estrogens in the male gonad.  

PubMed

The cytochrome P450 aromatase (P450arom) is a key enzyme responsible for the formation of estrogens from androgens and is present in the endoplasmic reticulum of various tissues. P450arom has been immunolocalized in Leydig cells of numerous species as well as in germ cells of mouse, bank vole and brown bear. Aromatase activity has been measured in vitro in immature and mature rat Leydig cells and Sertoli cells, whereas in pig, ram and humans the enzyme activity is only present in Leydig cells. In the mature rat testis we have used complementary approaches to demonstrate that not only somatic cells but also germ cells represent a new source of estrogens. In pachytene spermatocytes and Leydig cells, the amount of P450arom mRNA measured by a quantitative competitive RT-PCR method is 10-fold higher than in Sertoli cells. According to the stage of the germ cell maturation, the amount of aromatase transcripts decreases, being more elevated in younger than in mature rat germ cells. By contrast, the aromatase activity in the microsomal fractions is two- to four-fold greater in spermatozoa when compared to the two other enriched germ cell preparations used. We have immunolocalized the P450arom in elongated spermatids and spermatozoa. Moreover, we described the existence of alternative splicing events of P450arom mRNA in pachytene spermatocytes and round spermatids that are not likely to encode functional aromatase molecules. Therefore, the aromatase gene expression and its transduction in a fully active protein in rat germ cells evidences an additional site for estrogen production within the testis of some mammals. Taking into account the large distribution of estrogen receptors in the testicular cells, we begin to understand the physiological role of these female hormones in the male gonad. PMID:11403896

Carreau, S

2001-06-10

348

Doubly Uniparental Inheritance of Mitochondria As a Model System for Studying Germ Line Formation  

PubMed Central

Background Doubly Uniparental Inheritance (DUI) of mitochondria occurs when both mothers and fathers are capable of transmitting mitochondria to their offspring, in contrast to the typical Strictly Maternal Inheritance (SMI). DUI was found in some bivalve molluscs, in which two mitochondrial genomes are inherited, one through eggs, the other through sperm. During male embryo development, spermatozoon mitochondria aggregate in proximity of the first cleavage furrow and end up in the primordial germ cells, while they are dispersed in female embryos. Methodology/Principal Findings We used MitoTracker, microtubule staining and transmission electron microscopy to examine the mechanisms of this unusual distribution of sperm mitochondria in the DUI species Ruditapes philippinarum. Our results suggest that in male embryos the midbody deriving from the mitotic spindle of the first division concurs in positioning the aggregate of sperm mitochondria. Furthermore, an immunocytochemical analysis showed that the germ line determinant Vasa segregates close to the first cleavage furrow. Conclusions/Significance In DUI male embryos, spermatozoon mitochondria aggregate in a stable area on the animal-vegetal axis: in organisms with spiral segmentation this zone is not involved in cleavage, so the aggregation is maintained. Moreover, sperm mitochondria reach the same embryonic area in which also germ plasm is transferred. In 2-blastomere embryos, the segregation of sperm mitochondria in the same region with Vasa suggests their contribution in male germ line formation. In DUI male embryos, M-type mitochondria must be recognized by egg factors to be actively transferred in the germ line, where they become dominant replacing the Balbiani body mitochondria. The typical features of germ line assembly point to a common biological mechanism shared by DUI and SMI organisms. Although the molecular dynamics of the segregation of sperm mitochondria in DUI species are unknown, they could be a variation of the mechanism regulating the mitochondrial bottleneck in all metazoans. PMID:22140544

Milani, Liliana; Ghiselli, Fabrizio; Maurizii, Maria Gabriella; Passamonti, Marco

2011-01-01

349

Comparative molecular portraits of human unfertilized oocytes and primordial germ cells at 10 weeks of gestation.  

PubMed

Primordial germ cells (PGCs) are precursors of gametes and share several features in common with pluripotent stem cells, such as alkaline phosphatase activity and the expression of pluripotency-associated genes such as OCT4 and NANOG. PGCs are able to differentiate into oocytes and spermatogonia and establish totipotency after fertilization. However, our knowledge of human germ cell development is still fragmentary. In this study, we have carried out genome-wide comparisons of the transcriptomes and molecular portraits of human male PGCs (mPGCs), female PGCs (fPGCs) and unfertilized oocytes. We detected 9210 genes showing elevated expression in fPGCs, 9184 in mPGCs and 9207 in oocytes, with 6342 of these expressed in common. As well as known germ cell-related genes such as BLIMP1/PRDM1, PIWIL2, VASA/DDX4, DAZL, STELLA/DPPA3 and LIN28, we also identified 465 novel non-annotated genes with orthologs in the mouse. A plethora of olfactory receptor-encoding genes were detected in all samples, which would suggest their involvement not only in sperm chemotaxis, but also in the development of female germ cells and oocytes. We anticipate that our data might increase our meagre knowledge of the genes and associated signaling pathways operative during germ cell development. This in turn might aid in the development of strategies enabling better differentiation and molecular characterisation of germ cells derived from either embryonic or induced pluripotent stem cells. Ultimately, this would have a profound relevance for reproductive as well as regenerative medicine. PMID:23417401

Diedrichs, Ferdinand; Mlody, Barbara; Matz, Peggy; Fuchs, Heiko; Chavez, Lukas; Drews, Katharina; Adjaye, James

2012-01-01

350

Guar meal germ and hull fractions differently affect growth performance and intestinal viscosity of broiler chickens.  

PubMed

High concentrations of guar meal in poultry diets deleteriously affect growth, feed intake, and digesta viscosity. These effects are attributed to residual gum in the meal. A 2 x 5 factorial experiment investigated the impacts of two guar meal fractions (germ and hull) at five inclusion levels (0, 2.5, 5.0, 7.5, and 10.0%) on intestinal viscosity, measures of growth, and feed conversion in broiler chickens fed to 20 d of age. Growth and feed conversion ratio were not affected by inclusion of as much as 7.5% of the germ fraction into poultry diets, while inclusion of the hull fraction reduced growth at all concentrations. The hull fraction increased intestinal viscosity at all inclusion levels fed, although feed conversion was not affected until the inclusion rate exceeded 5.0%. The germ fraction significantly increased intestinal viscosity at 7.5 and 10% inclusion rates. When germ fraction was fed, relative organ weights remained constant through all concentrations except for the ventriculus and duodenum at 7.5 and 10% inclusion levels. Relative pancreas weight was significantly increased at the 10% level of the hull fraction. Increases in intestinal viscosity corresponded with growth depression. These results suggest that residual gum was responsible for some deleterious effects seen when guar meal was fed. The germ fraction was a superior ingredient when compared with the hull fraction. The guar meal germ fraction constituting as much as 7.5% of the diet supported growth and feed conversion measures similar to those observed with a typical corn-soybean poultry ration. PMID:14601737

Lee, J T; Bailey, C A; Cartwright, A L

2003-10-01

351

Systemic mastocytosis in a patient with ovarian germ cell carcinoma and mast cell leukemia  

SciTech Connect

We report a 12-year-old female with a history of mixed germ cell carcinoma of the right ovary who developed a generalized skin rash after oophorectomy and chemotherapy. She also presented with periodic episodes of flushing, anemia, tachycardia, shortness of breath, high fever, hepatosplenomegaly, nausea, abdominal cramping with diarrhea, and a papuloerythematous skin rash. There was no evidence of secondary carcinoma. Skin biopsy revealed nonspecific inflammatory cells with negative staining for mast cells. Peripheral blood smear showed an increased number of mast cells, thrombocytopenia and normal white cells count. Bone marrow showed hypercellularity with 38% of the nucleated cells being mast cells. Bone marrow chromosome analysis revealed hyperdiploidy in 30% of the cells: 58-64,XX, +1, +2, +5, +6, +7, +8, +14, +16, +18, +19, +19, +20, +21, +22. She expired two months after the occurrence of systemic mastocytosis. Systemic mastocytosis has been reported in association with hematopoietic disorders and with germ cell tumors. The association between mediastinal germ cell tumors and hematological malignancies has also been observed. To our knowledge, combination of most cell leukemia, systemic mastocytosis, and ovarian germ cell carcinoma has not been observed. It is know that mutations at the locus of either proto-oncogene c-kit receptor or its ligand, mast/stem cell factor (SCF) may impair the development of three stem cell populations: hematopoietic stem cells, germ cells and melanoblasts. There have been also extensive investigations on the expression and modulation of the SCF/c-kit interaction in various malignancies. Further molecular studies in patients with germ cell tumor/hematopoietic malignancy syndrome are required to delineate underlying mechanisms.

Sun, G.; Hajianpour, M.J.; Hajianpour, A.K. [Alfigen/The Genetics Institute, Pasadena, CA (United States)] [and others

1994-09-01

352

Sufficient Numbers of Early Germ Cells Are Essential for Female Sex Development in Zebrafish  

PubMed Central

The sex determination for zebrafish is controlled by a combination of genetic and environmental factors. The determination of sex in zebrafish has been suggested to rely on a mechanism that is affected by germ cell-derived signals. To begin our current study, a simplified and efficient germ cell-specific promoter of the dead end (dnd) gene was identified. Utilizing the metrodinazole (MTZ)/ bacterial nitroreductase (NTR) system for inducible germ cell ablation, several stable Tg (dnd:NTR-EGFP-3'UTR) and Tg (dnd:NTR-EGFP+3'UTR) zebrafish lines were then generated with the identified promoter. A thorough comparison of the expression patterns and tissue distributions of endogenous dnd and ntr-egfp transcripts in vivo revealed that the identified 2032-bp zebrafish dnd promoter can recapitulate dnd expression faithfully in stable transgenic zebrafish. The correlation between the levels of the germ cell-derived signals and requirement for maintaining the female fate has been also explored with different durations of the MTZ treatments. Our results revealed the decreasing ratios of female presented in the treated transgenic group are fairly associated with the reducing levels of the early germ cell-derived signals. After the juvenile transgenic fish treated with 5 mM MTZ for 20 days, all MTZ-treated transgenic fish exclusively developed into males with subfertilities. Taken together, our results identified here a simplified and efficient dnd promoter, and provide clear evidence indicating that it was not the presence but the sufficiency of signals derived from germ cells that is essential for female sex development in zebrafish. Our model also provides a unique system for sex control in zebrafish studies. PMID:25679390

Dai, Xiangyan; Jin, Xia; Chen, Xiaowen; He, Jiangyan; Yin, Zhan

2015-01-01

353

A set of genes critical to development is epigenetically poised in mouse germ cells from fetal stages through completion of meiosis  

E-print Network

In multicellular organisms, germ cells carry the hereditary material from one generation to the next. Developing germ cells are unipotent gamete precursors, and mature gametes are highly differentiated, specialized cells. ...

Lesch, Bluma J.

354

Modification of aqueous enzymatic oil extraction to increase the yield of corn oil from dry fractionated corn germ  

Technology Transfer Automated Retrieval System (TEKTRAN)

In previous aqueous enzymatic extraction experiments we reported an oil yield of 67 grams from 800 grams of dry fractionated corn germ. In the current experiments, a dispersion of 10% cooked, dry-fractionated germ in water and was treated with amylases and a cellulase complex. A foam fraction was s...

355

LIN-35/Rb causes starvation-induced germ cell apoptosis via CED-9/Bcl2 downregulation in Caenorhabditis elegans.  

PubMed

Apoptosis is an important mechanism for maintaining germ line health. In Caenorhabditis elegans, germ cell apoptosis occurs under normal conditions to sustain gonad homeostasis and oocyte quality. Under stress, germ cell apoptosis can be triggered via different pathways, including the following: (i) the CEP-1/p53 pathway, which induces germ cell apoptosis when animals are exposed to DNA damage; (ii) the mitogen-activated protein kinase kinase (MAPKK) pathway, which triggers germ cell apoptosis when animals are exposed to heat shock, oxidative stress, or osmotic stress; and (iii) an unknown mechanism that triggers germ cell apoptosis during starvation. Here, we address how starvation induces germ cell apoptosis. Using polysomal profiling, we found that starvation for 6 h reduces the translationally active ribosomes, which differentially affect the mRNAs of the core apoptotic machinery and some of its regulators. During starvation, lin-35/Rb mRNA increases its expression, resulting in the accumulation of this protein. As a consequence, LIN-35 downregulates the expression of the antiapoptotic gene ced-9/Bcl-2. We observed that the reduced translation of ced-9/Bcl-2 mRNA during food deprivation together with its downregulation drastically affects its protein accumulation. We propose that CED-9/Bcl-2 downregulation via LIN-35/Rb triggers germ cell apoptosis in C. elegans in response to starvation. PMID:24752899

Láscarez-Lagunas, L I; Silva-García, C G; Dinkova, T D; Navarro, R E

2014-07-01

356

LIN-35/Rb Causes Starvation-Induced Germ Cell Apoptosis via CED-9/Bcl2 Downregulation in Caenorhabditis elegans  

PubMed Central

Apoptosis is an important mechanism for maintaining germ line health. In Caenorhabditis elegans, germ cell apoptosis occurs under normal conditions to sustain gonad homeostasis and oocyte quality. Under stress, germ cell apoptosis can be triggered via different pathways, including the following: (i) the CEP-1/p53 pathway, which induces germ cell apoptosis when animals are exposed to DNA damage; (ii) the mitogen-activated protein kinase kinase (MAPKK) pathway, which triggers germ cell apoptosis when animals are exposed to heat shock, oxidative stress, or osmotic stress; and (iii) an unknown mechanism that triggers germ cell apoptosis during starvation. Here, we address how starvation induces germ cell apoptosis. Using polysomal profiling, we found that starvation for 6 h reduces the translationally active ribosomes, which differentially affect the mRNAs of the core apoptotic machinery and some of its regulators. During starvation, lin-35/Rb mRNA increases its expression, resulting in the accumulation of this protein. As a consequence, LIN-35 downregulates the expression of the antiapoptotic gene ced-9/Bcl-2. We observed that the reduced translation of ced-9/Bcl-2 mRNA during food deprivation together with its downregulation drastically affects its protein accumulation. We propose that CED-9/Bcl-2 downregulation via LIN-35/Rb triggers germ cell apoptosis in C. elegans in response to starvation. PMID:24752899

Láscarez-Lagunas, L. I.; Silva-García, C. G.; Dinkova, T. D.

2014-01-01

357

Analysis of a novel gene, Sdgc, reveals sex chromosome-dependent differences of medaka germ cells prior to gonad formation.  

PubMed

In vertebrates that have been examined to date, the sexual identity of germ cells is determined by the sex of gonadal somatic cells. In the teleost fish medaka, a sex-determination gene on the Y chromosome, DMY/dmrt1bY, is expressed in gonadal somatic cells and regulates the sexual identity of germ cells. Here, we report a novel mechanism by which sex chromosomes cell-autonomously confer sexually different characters upon germ cells prior to gonad formation in a genetically sex-determined species. We have identified a novel gene, Sdgc (sex chromosome-dependent differential expression in germ cells), whose transcripts are highly enriched in early XY germ cells. Chimeric analysis revealed that sexually different expression of Sdgc is controlled in a germ cell-autonomous manner by the number of Y chromosomes. Unexpectedly, DMY/dmrt1bY was expressed in germ cells prior to gonad formation, but knockdown and overexpression of DMY/dmrt1bY did not affect Sdgc expression. We also found that XX and XY germ cells isolated before the onset of DMY/dmrt1bY expression in gonadal somatic cells behaved differently in vitro and were affected by Sdgc. Sdgc maps close to the sex-determination locus, and recombination around the two loci appears to be repressed. Our results provide important insights into the acquisition and plasticity of sexual differences at the cellular level even prior to the developmental stage of sex determination. PMID:25078651

Nishimura, Toshiya; Herpin, Amaury; Kimura, Tetsuaki; Hara, Ikuyo; Kawasaki, Toshihiro; Nakamura, Shuhei; Yamamoto, Yasuhiro; Saito, Taro L; Yoshimura, Jun; Morishita, Shinichi; Tsukahara, Tatsuya; Kobayashi, Satoru; Naruse, Kiyoshi; Shigenobu, Shuji; Sakai, Noriyoshi; Schartl, Manfred; Tanaka, Minoru

2014-09-01

358

vasa and nanos expression patterns in a sea anemone and the evolution of bilaterian germ cell specification mechanisms  

E-print Network

ctenophores, acoelomorph flatworms, and cnidarians are ca- pable of asexual reproduction by budding, but also germ cells very differently from most extant bilaterians. Cnidarians and sponges have been reported to generate germ cells continuously throughout reproductive life, but previous studies on members

Extavour, Cassandra

359

The fate of isolated blastomeres with respect to germ cell formation in the amphipod crustacean Parhyale hawaiensis  

E-print Network

The fate of isolated blastomeres with respect to germ cell formation in the amphipod crustacean. In this paper, I use immunodetection of Vasa protein to study germ cell development in the amphipod crustacean amphipod development, including timing and symmetry of cell division, the transition from holoblastic

Extavour, Cassandra

360

Utility of the Germ Tube Test for Direct Identification of Candida albicans from Positive Blood Culture Bottles  

Microsoft Academic Search

We compared the germ tube test for the direct identification of Candida albicans from positive blood culture bottles, with results obtained from subcultured colonies. The direct germ tube test was 87.1% sensitive and 100% specific for the identification of C. albicans when the results obtained from fungal colonies were compared. Recent evidence has suggested that early institution of ap- propriate

Donald C. Sheppard; Marie-Claude Locas; Christiane Restieri; Michel Laverdiere

361

The DEAD-box protein MEL46 is required in the germ line of the nematode Caenorhabditis elegans  

Microsoft Academic Search

BACKGROUND: In the hermaphrodite of the nematode Caenorhabditis elegans, the first germ cells differentiate as sperm. Later the germ line switches to the production of oocytes. This process requires the activity of a genetic regulatory network that includes among others the fem, fog and mog genes. The function of some of these genes is germline specific while others also act

Ryuji Minasaki; Alessandro Puoti; Adrian Streit

2009-01-01

362

Ghrelin modulates testicular germ cells apoptosis and proliferation in adult normal rats  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. Black-Right-Pointing-Pointer Numerous studies have documented the direct action of ghrelin in the modulation of apoptosis in different cell types. Black-Right-Pointing-Pointer Ghrelin may be considered as a modulator of spermatogenesis in normal adult rats. Black-Right-Pointing-Pointer Ghrelin may be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors. -- Abstract: Under normal condition in the most mammals, spermatogenesis is closely associated with the balance between germ cells proliferation and apoptosis. The present study was designed to determine the effects of ghrelin treatment on in vivo quality and quantity expression of apoptosis and proliferation specific indices in rat testicular germ cells. Twenty eight adult normal rats were subdivided into equal control and treatment groups. Treatment group received 3 nmol of ghrelin as subcutaneous injection for 30 consecutive days or vehicle to the control animals. The rats from each group (n = 7) were killed on days 10 and 30 and their testes were taken for immunocytochemical evaluation and caspase-3 assay. Immunohistochemical analysis indicated that the accumulations of Bax and PCNA peptides are generally more prominent in spermatocytes and spermatogonia of both groups. Likewise, the mean percentage of immunoreactive spermatocytes against Bax increased (P < 0.01) in the ghrelin-treated group on day 10, while despite of 30% increment in the Bax level of spermatocytes in the treated rats on day 30, however, it was not statistically significant. During the experimental period, only a few spermatogonia represented Bax expression and the changes of Bax immunolabling cells were negligible upon ghrelin treatment. Likewise, there were immunostaining cells against Bcl-2 in each germ cell neither in the control nor in the treated animals. In fact, ghrelin balanced Bax/Bcl-2 ratio toward at increase of Bax level in the spermatocytes and therefore may stimulate apoptosis in these germ cells. In contrast, ghrelin administration significantly suppressed proliferation-associated peptide PCNA in the spermatocytes as well as spermatogonia (P < 0.05). Whereas, caspase-3 activity did not show any marked alteration during the experiment in both groups (P > 0.05). Upstream of Bax substance parallel to down-regulation of PCNA demonstrate that ghrelin may prevent massive accumulation of germ cells during normal spermatogenesis. These observations also indicate that ghrelin may be considered as a modulator of spermatogenesis in normal adult rats and could be potentially implicated for abnormal spermatogenesis in some testicular germ cell tumors.

Kheradmand, Arash, E-mail: arashkheradmand@yahoo.com [Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of)] [Department of Clinical Sciences, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Dezfoulian, Omid [Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorram Abad (Iran, Islamic Republic of)] [Department of Pathobiology, School of Veterinary Medicine, Lorestan University, Khorram Abad (Iran, Islamic Republic of); Alirezaei, Masoud [Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of)] [Division of Biochemistry, School of Veterinary Medicine, Lorestan University, P.O. Box: 465, Khorram Abad (Iran, Islamic Republic of); Rasoulian, Bahram [Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorram Abad (Iran, Islamic Republic of)] [Razi Herbal Medicine Research Center, Lorestan University of Medical Sciences, Khorram Abad (Iran, Islamic Republic of)

2012-03-09

363

Germ cells of the centipede Strigamia maritima are specified early in embryonic development  

E-print Network

annotation of the Strigamia genome (Chipman et al., submitted). The names and Ensembl IDs of this set are provided in Supplementary Table 1. We designed gene-specific primers for 8 of these putative germ line markers and amplified PCR products from embryonic... cDNA. The amplified fragments were cloned into pGEM-T Easy vector (Promega). The names, Ensembl IDs and primer sequences used for this set of 8 genes are provided in Supplementary Table 1. We screened these 8 possible germ line markers by examining...

Green, Jack E.; Akam, Michael

2014-06-12

364

Final Report of the First Refractory Germ Cell Tumor Treated with Sunitinib Malate.  

PubMed

Patients with advanced germ cell tumors can be cured with cisplatin-based chemotherapy, but the outcome remains unsatisfactory for patients with relapsed disease, including those patients with refractory disease after bone marrow transplantation. Targeted therapies have changed the standard of care for many advanced solid tumors. We have identified, in the literature, potential targets for the treatment of refractory germ cell tumors, and applied to a patient with a refractory disease. We chose sunitinib for this purpose. To our knowledge, this is the first case to be treated with sunitinib, and we have found a promising activity. PMID:20737043

Gasent Blesa, Joan Manel; Grande Pulido, Enrique; Laforga Canales, Juan; Alberola Candel, Vicente

2009-01-01

365

Final Report of the First Refractory Germ Cell Tumor Treated with Sunitinib Malate  

PubMed Central

Patients with advanced germ cell tumors can be cured with cisplatin-based chemotherapy, but the outcome remains unsatisfactory for patients with relapsed disease, including those patients with refractory disease after bone marrow transplantation. Targeted therapies have changed the standard of care for many advanced solid tumors. We have identified, in the literature, potential targets for the treatment of refractory germ cell tumors, and applied to a patient with a refractory disease. We chose sunitinib for this purpose. To our knowledge, this is the first case to be treated with sunitinib, and we have found a promising activity. PMID:20737043

Gasent Blesa, Joan Manel; Grande Pulido, Enrique; Laforga Canales, Juan; Alberola Candel, Vicente

2009-01-01

366

Sertoli cell-conditioned medium induces germ cell differentiation in human embryonic stem cells  

Microsoft Academic Search

Purpose  To investigate the spontaneous germ cell differentiation capacity of VUB hESC lines, develop a protocol for the induction\\u000a of germ cell differentiation using conditioned medium from Sertoli cells (SCCM) and compare it to existing protocols.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  hESC were allowed to differentiate spontaneously or after the addition of bone morphogenetic proteins (BMPs) and\\/or SCCM.\\u000a VASA transcripts were measured by relative quantification real-time

Mieke Geens; Karen Dora Sermon; Hilde Van de Velde; Herman Tournaye

2011-01-01

367

Radical Resection of a Late-Relapsed Testicular Germ Cell Tumour: Hepatectomy, Cavotomy, and Thrombectomy  

PubMed Central

Up to 3.2% of patients with testicular germ cell tumours represent with late-relapsing disease. Aggressive surgical resection confers the greatest chance of cure in this patient group. We present the case of a late and extensively relapsed nonseminomatous germ cell tumour with thrombus present along the entire length of the inferior vena cava, as well as in the right hepatic vein. Techniques practised in liver transplantation were used to achieve complete resection of the tumour thrombus. This case illustrates the enhanced potential for tumour resection through a fusion of principles derived from surgical oncology and liver transplantation. PMID:25587480

Ní Leidhin, C.; Redmond, C. E.; Cahalane, A. M.; Heneghan, H. M.; Motyer, R.; Ryan, E. R.; Hoti, E.

2014-01-01

368

Histological analysis of spermatogenesis and the germ cell development strategy within the testis of the male Western Cottonmouth Snake, Agkistrodon piscivorus leucostoma.  

PubMed

Cottonmouth (Agkistrodon piscivorus leucostoma) testes were examined histologically to determine the germ cell development strategy employed during spermatogenesis. Testicular tissues from Cottonmouths were collected monthly from swamps around Hammond, Louisiana. Pieces of testis were fixed in Trump's fixative, dehydrated in ethanol, embedded in Spurr's plastic, sectioned with an ultramicrotome, and stained with toluidine blue and basic fuchsin. Spermatogenesis within Cottonmouths occurs in two independent events within a single calendar year. The testes are active during the months of March-June and August-October with spermiation most heavily observed during April-May and October. To our knowledge, this is the first study that describes bimodal spermatogenesis occurring in the same year within the subfamily Crotalinae. During spermatogenesis, no consistent spatial relationships are observed between germ cell generations. Typically, either certain cell types were missing (spermatocytes) or the layering of 3-5 spermatids and/or spermatocytes within the same cross-section of seminiferous tubule prevented consistent spatial stages from occurring. This temporal pattern of sperm development is different from the spatial development found within birds and mammals, being more reminiscent of that seen in amphibians, and has now been documented within every major clade of reptile (Chelonia, Serpentes, Sauria, Crocodylia). This primitive-like sperm development, within a testis structurally similar to mammals and birds, may represent an intermediate testicular model within the basally positioned (phylogenetically) reptiles that may be evolutionarily significant. PMID:18926676

Gribbins, Kevin M; Rheubert, Justin L; Collier, Matthew H; Siegel, Dustin S; Sever, David M

2008-11-20

369

Formation of germ-line cysts with a central cytoplasmic core is accompanied by specific orientation of mitotic spindles and partitioning of existing intercellular bridges  

Microsoft Academic Search

Animal germ cells tend to form clonal groups known as clusters or cysts. Germ cells within the cyst (cystocytes) are interconnected\\u000a by intercellular bridges and thus constitute a syncytium. Our knowledge of the mechanisms that control the formation of germ-cell\\u000a clusters comes from extensive studies carried on model organisms (Drosophila, Xenopus). Germ-cell clusters have also been described in worms (annelids,

Piotr ?wi?tek; Janusz Kubrakiewicz; Jerzy Klag

2009-01-01

370

Extended cervico-thoracic metastasectomy for testicular non-seminomatous germ cell tumour masses through an inverse T and combined collar incision.  

PubMed

Non-seminomatous germ cell tumours (NSGCT) are the most common malignancy from testicular origin in young males. They are characterized by early formation of metastases along retroperitoneal and subsequent mediastinal lymph node stations. Following cisplatin-based induction chemotherapy, residual tumour masses should be removed surgically, although this implies the need for extended procedures. Such an approach can result in cure rates of over 70%. Herein, we report 2 cases of maximally extended surgery for metastatic malignant germ cell tumour of the testis. In both patients, diagnostic work-up revealed a NSGCT with retroperitoneal, mediastinal and cervical lymph node metastases. Multimodal protocols including induction chemotherapy and surgical removal of all primary and secondary tumour masses with curative intent were applied. An 'inverse T' incision in combination with a collar incision was chosen to approach the excessive supra-diaphragmatic tumour spread. This large-scaled surgical access offered an excellent exposure and allowed complete resection of all cervical and thoracic metastases in both patients. Abdominal tumour masses were resected through a standard median laparotomy. These 2 cases illustrate that complete tumour resection is feasible even in stages of NSGCT with generalized lymphatic spread. Metastasectomy should be offered to NSGCT patients despite the necessity of extended surgical approaches. PMID:24925077

Schweiger, Thomas; Hoetzenecker, Konrad; Taghavi, Shahrokh; Klepetko, Walter

2015-05-01

371

Effects of wheat germ agglutinin on human gastrointestinal epithelium: Insights from an experimental model of immune/epithelial cell interaction  

SciTech Connect

Wheat germ agglutinin (WGA) is a plant protein that binds specifically to sugars expressed, among many others, by human gastrointestinal epithelial and immune cells. WGA is a toxic compound and an anti-nutritional factor, but recent works have shown that it may have potential as an anti-tumor drug and as a carrier for oral drugs. To quantitate the toxicity threshold for WGA on normal epithelial cells we previously investigated the effects of the lectin on differentiated Caco2 cells, and showed that in the micromolar range of concentrations WGA could alter the integrity of the epithelium layer and increase its permeability to both mannitol and dextran. WGA was shown to be uptaken by Caco2 cells and only {approx} 0.1% molecules were observed to cross the epithelium layer by transcytosis. Here we show that at nanomolar concentrations WGA is unexpectedly bioactive on immune cells. The supernatants of WGA-stimulated peripheral blood mononuclear cells (PBMC) can alter the integrity of the epithelium layer when administered to the basolateral side of differentiated Caco2 cells and the effects can be partially inhibited by monoclonal antibodies against IL1, IL6 and IL8. At nanomolar concentrations WGA stimulates the synthesis of pro-inflammatory cytokines and thus the biological activity of WGA should be reconsidered by taking into account the effects of WGA on the immune system at the gastrointestinal interface. These results shed new light onto the molecular mechanisms underlying the onset of gastrointestinal disorders observed in vivo upon dietary intake of wheat-based foods.

Pellegrina, Chiara Dalla [Department of Biotechnology, University of Verona, Strada Le Grazie 15-CV1, I-37134 Verona (Italy); Perbellini, Omar [Department of Clinical and Experimental Medicine, University of Verona, I-37134 Verona (Italy); Scupoli, Maria Teresa [Department of Clinical and Experimental Medicine, University of Verona, I-37134 Verona (Italy); Interdepartmental Laboratory for Medical Research, University of Verona, I-37134 Verona (Italy); Tomelleri, Carlo [Department of Clinical and Experimental Medicine, University of Verona, I-37134 Verona (Italy); Zanetti, Chiara; Zoccatelli, Gianni; Fusi, Marina; Peruffo, Angelo; Rizzi, Corrado [Department of Biotechnology, University of Verona, Strada Le Grazie 15-CV1, I-37134 Verona (Italy); Chignola, Roberto [Department of Biotechnology, University of Verona, Strada Le Grazie 15-CV1, I-37134 Verona (Italy)], E-mail: roberto.chignola@univr.it

2009-06-01

372

MEETING REPORT ASSESSING HUMAN GERM-CELL MUTAGENESIS IN THE POST-GENOME ERA: A CELEBRATION OF THE LEGACY OF WILLIAM LAWSON (BILL) RUSSELL  

EPA Science Inventory

Although numerous germ-cell mutagens have been identified in animal model systems, to date, no human germ-cell mutagens have been confirmed. Because the genomic integrity of our germ cells is essential for the continuation of the human species, a resolution of this enduring conu...

373

T e c h n i c a l B u l l e t i n TNT Coupled Wheat Germ  

E-print Network

T e c h n i c a l B u l l e t i n TNT® Coupled Wheat Germ Extract Systems INSTRUCTIONS FOR USE A. General Protocol for TNT® Wheat Germ Extract Coupled Transcription/Translation Reactions.................................................................................................21 I. Description The TNT® Coupled Wheat Germ Extract Systems(a­d) offer researchers an alternative

Kirschner, Marc W.

374

WHEAT GERM OIL AND A LOW WASTE LIQUID LARVAL DIET FOR REARING ORIENTAL FRUIT FLIES, BACTROCERA DORSALIS(HENDEL) (DIPTERA: TEPHRITIDAE)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Wheat germ oil was added into a low waste larval liquid diet for rearing Bactrocera dorsalis (Hendel) to optimize the fruit fly performance. Various concentrations of 0.04, 0.07, 0.15, 0.30, and 0.66 % of wheat germ oil were evaluated. Results showed that the addition of wheat germ oil did not affec...

375

GLD-4-Mediated Translational Activation Regulates the Size of the Proliferative Germ Cell Pool in the Adult C. elegans Germ Line  

PubMed Central

To avoid organ dysfunction as a consequence of tissue diminution or tumorous growth, a tight balance between cell proliferation and differentiation is maintained in metazoans. However, cell-intrinsic gene expression mechanisms controlling adult tissue homeostasis remain poorly understood. By focusing on the adult Caenorhabditis elegans reproductive tissue, we show that translational activation of mRNAs is a fundamental mechanism to maintain tissue homeostasis. Our genetic experiments identified the Trf4/5-type cytoplasmic poly(A) polymerase (cytoPAP) GLD-4 and its enzymatic activator GLS-1 to perform a dual role in regulating the size of the proliferative zone. Consistent with a ubiquitous expression of GLD-4 cytoPAP in proliferative germ cells, its genetic activity is required to maintain a robust proliferative adult germ cell pool, presumably by regulating many mRNA targets encoding proliferation-promoting factors. Based on translational reporters and endogenous protein expression analyses, we found that gld-4 activity promotes GLP-1/Notch receptor expression, an essential factor of continued germ cell proliferation. RNA-protein interaction assays documented also a physical association of the GLD-4/GLS-1 cytoPAP complex with glp-1 mRNA, and ribosomal fractionation studies established that GLD-4 cytoPAP activity facilitates translational efficiency of glp-1 mRNA. Moreover, we found that in proliferative cells the differentiation-promoting factor, GLD-2 cytoPAP, is translationally repressed by the stem cell factor and PUF-type RNA-binding protein, FBF. This suggests that cytoPAP-mediated translational activation of proliferation-promoting factors, paired with PUF-mediated translational repression of differentiation factors, forms a translational control circuit that expands the proliferative germ cell pool. Our additional genetic experiments uncovered that the GLD-4/GLS-1 cytoPAP complex promotes also differentiation, forming a redundant translational circuit with GLD-2 cytoPAP and the translational repressor GLD-1 to restrict proliferation. Together with previous findings, our combined data reveals two interconnected translational activation/repression circuitries of broadly conserved RNA regulators that maintain the balance between adult germ cell proliferation and differentiation. PMID:25254367

Millonigg, Sophia; Eckmann, Christian R.

2014-01-01

376

GLD-4-mediated translational activation regulates the size of the proliferative germ cell pool in the adult C. elegans germ line.  

PubMed

To avoid organ dysfunction as a consequence of tissue diminution or tumorous growth, a tight balance between cell proliferation and differentiation is maintained in metazoans. However, cell-intrinsic gene expression mechanisms controlling adult tissue homeostasis remain poorly understood. By focusing on the adult Caenorhabditis elegans reproductive tissue, we show that translational activation of mRNAs is a fundamental mechanism to maintain tissue homeostasis. Our genetic experiments identified the Trf4/5-type cytoplasmic poly(A) polymerase (cytoPAP) GLD-4 and its enzymatic activator GLS-1 to perform a dual role in regulating the size of the proliferative zone. Consistent with a ubiquitous expression of GLD-4 cytoPAP in proliferative germ cells, its genetic activity is required to maintain a robust proliferative adult germ cell pool, presumably by regulating many mRNA targets encoding proliferation-promoting factors. Based on translational reporters and endogenous protein expression analyses, we found that gld-4 activity promotes GLP-1/Notch receptor expression, an essential factor of continued germ cell proliferation. RNA-protein interaction assays documented also a physical association of the GLD-4/GLS-1 cytoPAP complex with glp-1 mRNA, and ribosomal fractionation studies established that GLD-4 cytoPAP activity facilitates translational efficiency of glp-1 mRNA. Moreover, we found that in proliferative cells the differentiation-promoting factor, GLD-2 cytoPAP, is translationally repressed by the stem cell factor and PUF-type RNA-binding protein, FBF. This suggests that cytoPAP-mediated translational activation of proliferation-promoting factors, paired with PUF-mediated translational repression of differentiation factors, forms a translational control circuit that expands the proliferative germ cell pool. Our additional genetic experiments uncovered that the GLD-4/GLS-1 cytoPAP complex promotes also differentiation, forming a redundant translational circuit with GLD-2 cytoPAP and the translational repressor GLD-1 to restrict proliferation. Together with previous findings, our combined data reveals two interconnected translational activation/repression circuitries of broadly conserved RNA regulators that maintain the balance between adult germ cell proliferation and differentiation. PMID:25254367

Millonigg, Sophia; Minasaki, Ryuji; Nousch, Marco; Eckmann, Christian R

2014-09-01

377

Primary hyperparathyroidism  

Microsoft Academic Search

Opinion statement  Treatment of primary hyperparathyroidism depends on a clear diagnosis based on biochemical confirmation. Most patients have\\u000a an elevated serum total or ionized calcium level in association with an elevated or inappropriate serum intact parathyroid\\u000a hormone level. The serum calcium level can be lowered by hydration and by a variety of pharmacologic agents. However, none\\u000a of these agents is effective

Robert Udelsman

2001-01-01

378

ANEUPLOIDIES AND MICRONUCLEI IN THE GERM CELLS OF MALE MICE OF ADVANCED AGE  

EPA Science Inventory

The objective of this research was to determine whether the frequencies of chromosomally defective germ cells increased with age in male laboratory mice. wo types of chromosomal abnormalities were characterized: (1) testicular spermatid aneuploidy (TSA) as measured by a new metho...

379

February 1, 2004 Page 1 of 2 Stopping Germs at Home, Work and School  

E-print Network

infection of concern in schools -- nearly 22 million schools days are lost each year to the common cold, the common cold, and other illnesses. See Other Resources and Posters on this Stop the Spread of Germs site and Bloomfield, 1989) · Nearly 22 million school days are lost annually due to the common cold alone. (CDC, 1996

Burke, Peter

380

Composition and oxidative stability of crude oil extracts of corn germ and distillers grains  

Technology Transfer Automated Retrieval System (TEKTRAN)

The fatty acid composition, Acid Value, and the content and composition of tocopherols, tocotrienols, carotenoids, phytosterols, and steryl ferulates were determined in corn germ oil and four post-fermentation corn oils from the ethanol dry grind process. The oxidative stability index at 110ºC was ...

381

Human primordial germ cell commitment in vitro associates with a unique PRDM14 expression profile.  

PubMed

Primordial germ cells (PGCs) develop only into sperm and oocytes in vivo. The molecular mechanisms underlying human PGC specification are poorly understood due to inaccessibility of cell materials and lack of in vitro models for tracking the earliest stages of germ cell development. Here, we describe a defined and stepwise differentiation system for inducing pre-migratory PGC-like cells (PGCLCs) from human pluripotent stem cells (PSCs). In response to cytokines, PSCs differentiate first into a heterogeneous mesoderm-like cell population and then into PGCLCs, which exhibit minimal PRDM14 expression. PGC specification in humans is similar to the murine process, with the sequential activation of mesodermal and PGC genes, and the suppression of neural induction and of de novo DNA methylation, suggesting that human PGC formation is induced via epigenesis, the process of germ cell specification via inductive signals from surrounding somatic cells. This study demonstrates that PGC commitment in humans shares key features with that of the mouse, but also highlights key differences, including transcriptional regulation during the early stage of human PGC development (3-6 weeks). A more comprehensive understanding of human germ cell development may lead to methodology for successfully generating PSC-derived gametes for reproductive medicine. PMID:25750208

Sugawa, Fumihiro; Araúzo-Bravo, Marcos J; Yoon, Juyong; Kim, Kee-Pyo; Aramaki, Shinya; Wu, Guangming; Stehling, Martin; Psathaki, Olympia E; Hübner, Karin; Schöler, Hans R

2015-04-15

382

ORIGINAL ARTICLE Patterns of molecular evolution of the germ line specification  

E-print Network

the Oskar proteins of D. melanogaster and D. virilis. This molecular evolutionary analysis thus representsORIGINAL ARTICLE Patterns of molecular evolution of the germ line specification gene oskar suggest an important role in posterior patterning. A novel N-terminal domain of oskar(the Long Oskar domain) evolved

Extavour, Cassandra

383

Temporal germ cell development strategy during continuous spermatogenesis within the montane lizard, Sceloporus bicanthalis (Squamata; Phrynosomatidae).  

PubMed

Sceloporus bicanthalis is a viviparous lizard that lives at higher elevations in Mexico. Adult male S. bicanthalis were collected (n = 36) from the Nevado de Toluca, Mexico (elevation is 4200 m) during August to December, 2007 and January to July, 2008. Testes were extracted, fixed in Trumps, and dehydrated in a graded series of ethanol. Tissues were embedded, sectioned (2 ?m), stained, and examined via a light microscope to determine the spermatogenic developmental strategy of S. bicanthalis. In all months examined, the testes were spermiogenically active; based on this, plus the presence of sperm in the lumina of seminiferous tubules, we inferred that S. bicanthalis had year-round or continuous spermatogenesis, unlike most reptiles that occupy a temperate or montane habitat. It was recently reported that seasonally breeding reptiles had a temporal germ cell development strategy similar to amphibians, where germ cells progress through spermatogenesis as a single population, which leads to a single spermiation event. This was much different than spatial development within the testis of other derived amniotes. We hypothesized that germ cell development was temporal in S. bicanthalis. Therefore, we wanted to determine whether reptiles that practice continuous spermatogenesis have a mammalian-like spatial germ cell development, which is different than the typical temperate reptile exhibiting a temporal development. In the present study, S. bicanthalis had a temporal development strategy, despite its continuous spermatogenic cycle, making them similar to tropical anoles. PMID:21752450

Gribbins, Kevin; Anzalone, Marla; Collier, Matthew; Granados-González, Gisela; Villagrán-Santa Cruz, Maricela; Hernández-Gallegos, Oswaldo

2011-10-01

384

Mouse Ovarian Germ Cell Cysts Undergo Programmed Breakdown to Form Primordial Follicles  

Microsoft Academic Search

In many organisms, early germline development takes place within cysts of interconnected cells that form by incomplete cytokinesis and later undergo programmed breakdown. We recently identified similar cell clusters within the fetal mouse ovary, but the fate and functional significance of these germ cell cysts remained unclear. Here, we show that mouse cysts undergo programmed breakdown between 20.5–22.5 dpc, during

Melissa E. Pepling; Allan C. Spradling

2001-01-01

385

Isolation and characterization of a cDNA clone encoding wheat germ agglutinin  

SciTech Connect

Two sets of synthetic oligonucleotides coding for amino acids in the amino- and carboxyl-terminal portions of wheat germ agglutinin were synthesized and used as hybridization probes to screen cDNA libraries derived from developing embryos of tetraploid wheat. The nucleotide sequence for a cDNA clone recovered from the cDNA library was determined by dideoxynucleotide chain-termination sequencing in vector M13. The amino acid sequence deduced from the DNA sequence indicated that this cDNA clone (pNVR1) encodes isolectin 3 of wheat germ agglutinin. Comparison of the deduced amino acid sequence of clone pNVR1 with published sequences indicates isolectin 3 differs from isolectins 1 and 2 by 10 and 8 amino acid changes, respectively. In addition, the protein encoded by pNVR1 extends 15 amino acids beyond the carboxyl terminus of the published amino acid sequence for isolectins 1 and 2 and includes a potential site for N-linked glycosylation. Utilizing the insert of pNVR1 as a hybridization probe, the authors have demonstrated that the expression of genes for wheat germ agglutinin is modulated by exogenous abscisic acid. Striking homology is observed between wheat germ agglutinin and chitinase, both of which are proteins that bind chitin.

Raikhel, N.V.; Wilkins, T.A.

1987-10-01

386

The emerging role of matrix metalloproteases of the ADAM family in male germ cell apoptosis  

PubMed Central

Constitutive germ cell apoptosis during mammalian spermatogenesis is a key process for controlling sperm output and to eliminate damaged or unwanted cells. An increase or decrease in the apoptosis rate has deleterious consequences and leads to low sperm production. Apoptosis in spermatogenesis has been widely studied, but the mechanism by which it is induced under physiological or pathological conditions has not been clarified. We have recently identified the metalloprotease ADAM17 (TACE) as a putative physiological inducer of germ cell apoptosis. The mechanisms involved in regulating the shedding of the ADAM17 extracellular domain are still far from being understood, although they are important in order to understand cell-cell communications. Here, we review the available data regarding apoptosis during mammalian spermatogenesis and the localization of ADAM proteins in the male reproductive tract. We propose an integrative working model where ADAM17, p38 MAPK, protein kinase C (PKC) and the tyrosine kinase c-Abl participate in the physiological signalling cascade inducing apoptosis in germ cells. In our model, we also propose a role for the Sertoli cell in regulating the Fas/FasL system in order to induce the extrinsic pathway of apoptosis in germ cells. This working model could be applied to further understand constitutive apoptosis in spermatogenesis and in pathological conditions (e.g., varicocele) or following environmental toxicants exposure (e.g., genotoxicity or xenoestrogens). PMID:22319668

Urriola-Muñoz, Paulina; Lagos-Cabré, Raúl

2011-01-01

387

Synchronous bilateral testicular germ cell tumour: case report and review of the literature.  

PubMed

We report a case of a 30 years old male affected by synchronous bilateral germ cell tumor with a history of unilateral cryptorchidism; the patient underwent surgical treatment followed by adjuvant radiotherapy on paraaortic and iliac lymphnodes. Patients with synchronous tumors usually present with a higher stage disease in contrast to those with unilateral testicular carcinoma, yet the prognosis remains equally favorable. PMID:23961859

Detti, B; Scoccianti, S; Cassani, S; Franzese, C; Di Cataldo, V; Villari, D; Cai, T; Desideri, I; Livi, L; Lapini, A; Nicita, G; Carini, M; Biti, G

2013-01-01

388

Clean and DisinfectClean and DisinfectClean and Disinfect Germ Fighting 101  

E-print Network

A dishwashing machine can substitute in cleaning and disinfecting of toys and dishes 1. Clean surfaceClean and DisinfectClean and DisinfectClean and Disinfect Germ Fighting 101 Non-Porous Surfaces. Clean toys and dishes with a mild detergent to remove visible signs of dirt and food 2. Rinse completely

389

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer  

PubMed Central

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25493378

Selle, F.; Gligorov, J.; Richard, S.; Khalil, A.; Alexandre, I.; Avenin, D.; Provent, S.; Soares, D.G.; Lotz, J.P.

2014-01-01

390

Angiotensin I Converting enzyme inhibitory peptides from commercial wet- and dry-milled corn germ  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bioprocesses were developed to enhance the value of proteins from de-oiled corn germ. Proteins were hydrolyzed with trypsin, GC106, Flavourzyme or thermolysin in order to free the bioactive peptide sequences. Protein hydrolysis, at an enzyme to substrate ratio of 1:250, was greater for wet- than d...

391

Reduced numbers of Sertoli, germ, and spermatogonial stem cells in impaired spermatogenesis  

Microsoft Academic Search

A key step in the investigation of male infertility is the appropriate classification of impaired spermatogenesis. In this study, we precisely identified Sertoli and distinct germ-cell types in the rat, the mouse, and in the human testis. As a proof of principle, we studied testis biopsy samples from azoospermic patients with defined spermatogenic defects. Remarkably, we found that already the

Anna Hentrich; Martin Wolter; Carolin Szardening-Kirchner; Georg H Lüers; Martin Bergmann; Sabine Kliesch; Lutz Konrad

2011-01-01

392

Small RNA guides for de novo DNA methylation in mammalian germ cells  

PubMed Central

Germline genomic methylation is essential for gamete identity and integrity in mammals. The study by Kuramochi-Miyagawa and colleagues (908–917) in the previous issue of Genes & Development links the process of DNA methylation-dependent repression of retrotranspons with the presence of piwi-interacting RNAs (piRNAs) in fetal male germ cells undergoing de novo methylation. PMID:18413711

Aravin, Alexei A.; Bourc’his, Déborah

2008-01-01

393

Quantification of Vitamin E and gamma-Oryzanol Components in Rice Germ and Bran  

Technology Transfer Automated Retrieval System (TEKTRAN)

Rice bran is a rich natural source of vitamin E and gamma-oryzanol, which have been extensively studied and reported to possess important health-promoting properties. However, commercial rice bran is a mixture of rice bran and germ, and profiles of vitamin E and gamma-oryzanol components in these tw...

394

Caenorhabditis elegans caspase homolog CSP-2 inhibits CED-3 autoactivation and apoptosis in germ  

E-print Network

with that of somatic apoptosis. In particular, CED-3, CED-4, and CED-9 are essential for apoptosis in both germ cells apoptosis in somatic cells. These include the CED-3 caspase, the CED-3 activator CED-4, and the cell death autoactivation, but does not inhibit CED-4-induced CED-3 activation or the activity of the activated CED-3

Xue, Ding

395

C. elegans caspase homolog CSP-2 inhibits CED-3 autoactivation and apoptosis in germ cells  

PubMed Central

In C. elegans, apoptosis in germ cells is mediated by the same core apoptotic machinery that controls apoptosis in somatic cells. These include the CED-3 caspase, the CED-3 activator CED-4, and the cell death inhibitor CED-9. However, germline apoptosis also differs from somatic apoptosis in its regulation. We found that CSP-3, a caspase homolog that blocks CED-3 autoactivation and apoptosis in somatic cells, does not affect apoptosis in germ cells. Interestingly, the second C. elegans caspase homolog CSP-2 shares sequence similarity to both catalytic subunits of the CED-3 caspase, and surprisingly, contains a stretch of sequence that is almost identical to that of CSP-3. Unlike CSP-3 that acts specifically in somatic cells, loss of CSP-2 causes increased apoptosis only in germ cells, suggesting that CSP-2 is a germ cell specific apoptosis inhibitor. Moreover, like CSP-3, CSP-2 associates with the CED-3 zymogen and inhibits its autoactivation, but does not inhibit CED-4-induced CED-3 activation or the activity of the activated CED-3 protease. Thus, two different C. elegans caspase homologs employ the same mechanism to prevent caspase autoactivation and apoptosis in different tissues, suggesting that this could be a generally applicable strategy for regulating caspase activation and apoptosis. PMID:19575016

Geng, X; Zhou, QH; Kage-Nakadai, E; Shi, Y; Yan, N; Mitani, S; Xue, D

2009-01-01

396

The Germination of Sporangiospores of Rhizopus arrhizus; Spore Swelling and Germ-Tube Emergence  

Microsoft Academic Search

SUMMARY The germination of sporangiospores of Rhixopw arrhizw was investi- gated, and differing requirements found for the initiation of germination, spore swelling and germ-tube emergence. The initiation of germination, as indicated by the commencement of swelling and by the spores becoming permeable to methylene blue, requires the presence of glucose or fructose. Maximal spore swelling requires in addition the presence

J. A. Ekundayo; M. J. Carlile

1964-01-01

397

Increased mortality rates in young and middle-aged patients with malignant germ cell tumours  

Microsoft Academic Search

Cisplatin-based chemotherapy of malignant germ cell tumours (MGCT) has been reported to increase the risk of cardiovascular morbidity. A high incidence of second nongerm cell malignancies is well documented in MGCT survivors. The death risk due to these conditions is, however, more unknown in MGCT patients. Standard mortality rates (SMRs) were established in 3378 Norwegian MGCT patients treated from 1962

S D Fosså; N Aass; S Harvei; S Tretli

2004-01-01

398

Determination of Cancer Risk Associated with Germ Line BRCA1 Missense Variants by Functional Analysis  

E-print Network

Determination of Cancer Risk Associated with Germ Line BRCA1 Missense Variants by Functional Analysis Marcelo A. Carvalho, 1,3 Sylvia M. Marsillac, 1,4 Rachel Karchin, 6 Siranoush Manoukian, 7 Scott Andrej Sali, 13 David Goldgar, 14 Fergus J. Couch, 15 Paolo Radice, 7,8 and Alvaro N.A. Monteiro 1 1 Risk

Sali, Andrej

399

Regulation of sex chromosome constitution of somatic and germ cells in the wood lemming  

E-print Network

Regulation of sex chromosome constitution of somatic and germ cells in the wood lemming A. GROPP K displays certain peculiar features. (a) The sex ratio shows a prevalence of females, and some females produce only female offspring. (b) A conside- rable proportion of the females has XY sex chromosomes

Paris-Sud XI, Université de

400

Sex chromosome inactivation in germ cells: emerging roles of DNA damage response pathways  

E-print Network

REVIEW Sex chromosome inactivation in germ cells: emerging roles of DNA damage response pathways / Accepted: 13 February 2012 / Published online: 2 March 2012 Ó Springer Basel AG 2012 Abstract Sex. Recent progress has revealed the underlying mechanisms of sex chromosome inactivation in male meiosis

Dean, Matthew D.

401

Molecular Genetic Parameters in Pathogenesis and Prognosis of Testicular Germ Cell Tumors  

Microsoft Academic Search

Aim of this review article was to critically analyze the recently described cytogenetic and molecular markers for testicular germ cell tumors with regard to their clinical utility. The isochromosme i(12p) represents the most common and characteristic cytogenetic finding which already appears in testicular carcinoma in situ. A number of proto–oncogenes (cyclin D and PTHLH) as well as putative tumor suppressor

A. Heidenreich; S. Srivastava; J. W. Moul; R. Hofmann; C. R. Chapple; K. Fujikawa; S. Fukuzawa

2000-01-01

402

Use of corn germ meal in diets for pond-raised channel catfish, Ictalurus punctatus  

Technology Transfer Automated Retrieval System (TEKTRAN)

Corn germ meal (CGM) is a by-product of corn milling. On the basis of its nutrient composition and digestibility values, it appears to be a suitable ingredient for use in channel catfish, Ictalurus punctatus, diets. A study was conducted to examine the use of various levels of CGM in diets for pond-...

403

Germ-cell death during prespermatogenesis in the testis of the golden hamster  

Microsoft Academic Search

Degenerating prespermatogonial germ cells in the testis of the immature golden hamster [aged 14 days post conceptionem (dpc) to 13 days post partum [dpp)] were studied with regard to their morphology and temporal incidence. Judged by their ultrastructural features, these cells clearly take the form of apoptosis and finally are subjected to phagocytosis by neighboring Sertoli cells; only a few

Andreas Miething

1992-01-01

404

Drosophila melanogaster Male Germ Line-Specific Autosomal and Y-Linked Genes Transcripts With  

Microsoft Academic Search

We have identified of set of related transcripts expressed in the germ line of male Drosophila melanogaster. Surprisingly, while one of the corresponding genes is autosomal the remainder are located on the Y chromosome. The autosomal locus, at 77F on chromosome arm 3L, corresponds to the previously described transcription unit 18c, located in the first intron of the gene for

Steven R. H. Russell; Kim Kaiser

405

HiTrap Affinity columns HiTrap Wheat Germ Lectin, 1 ml INSTRUCTIONS  

E-print Network

-linked oligosaccharides, [GlcNAc(b1,4GlcNAc)1-2 > bGlcNAc] N-acetylgalactosamine/galactose binding lectins Peanut Lectin or refilled. 3 #12;The characteristics of the product are summarised below. Table 3. HiTrap Wheat Germ Lectin

Lebendiker, Mario

406

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer.  

PubMed

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25493378

Selle, F; Gligorov, J; Richard, S; Khalil, A; Alexandre, I; Avenin, D; Provent, S; Soares, D G; Lotz, J P

2015-01-01

407

Intensive chemotherapy as salvage treatment for solid tumors: focus on germ cell cancer.  

PubMed

Germ cell tumors present contrasting biological and molecular features compared to many solid tumors, which may partially explain their unusual sensitivity to chemotherapy. Reduced DNA repair capacity and enhanced induction of apoptosis appear to be key factors in the sensitivity of germ cell tumors to cisplatin. Despite substantial cure rates, some patients relapse and subsequently die of their disease. Intensive doses of chemotherapy are used to counter mechanisms of drug resistance. So far, high-dose chemotherapy with hematopoietic stem cell support for solid tumors is used only in the setting of testicular germ cell tumors. In that indication, high-dose chemotherapy is given as the first or late salvage treatment for patients with either relapsed or progressive tumors after initial conventional salvage chemotherapy. High-dose chemotherapy is usually given as two or three sequential cycles using carboplatin and etoposide with or without ifosfamide. The administration of intensive therapy carries significant side effects and can only be efficiently and safely conducted in specialized referral centers to assure optimum patient care outcomes. In breast and ovarian cancer, most studies have demonstrated improvement in progression-free survival (PFS), but overall survival remained unchanged. Therefore, most of these approaches have been dropped. In germ cell tumors, clinical trials are currently investigating novel therapeutic combinations and active treatments. In particular, the integration of targeted therapies constitutes an important area of research for patients with a poor prognosis. PMID:25372715

Selle, F; Gligorov, J; Richard, S; Khalil, A; Alexandre, I; Avenin, D; Provent, S; Soares, D G; Lotz, J P

2014-11-01

408

Gene Expression Analysis during Conidial Germ Tube and Appressorium Development in Colletotrichum trifolii  

PubMed Central

Preinfection development in Colletotrichum spp. exhibits three morphologies (conidia, germ tubes, and appressoria) and is directed by a complex interplay of environmental signals. Germ tube morphogenesis for Colletotrichum trifolii and the related fungus Colletotrichum gloeosporioides f. sp. aeschynomene was shown to be partially dependent on a balance between self-germination inhibitors and environmental nutrients or cutin. The degree of responsiveness to these environmental signals was strikingly different between the two fungal species. A solid contact surface stimulated germ tube morphogenesis and was the only apparent requirement for appressorium morphogenesis in both fungi. A population of C. trifolii conidia was incubated on a solid surface in the presence of cutin to stimulate nearly synchronous preinfection morphogenesis for gene expression analysis. RNA analysis of signal-transducing genes from C. trifolii, including genes for a serine-threonine kinase (TB3), calmodulin, and protein kinase C, showed that maximum transcription of all three genes occurred in conidia prior to or during germ tube morphogenesis. Transcription of melanin biosynthetic genes THR1 and SCD1 (Y. Kubo, Y. Takano, and I. Furusawa, Colletotrichum Newsl. II:5-10, 1996; N. S. Perpetua, Y. Kubo, N. Yasuda, Y. Takano, and I. Furusawa, Mol. Plant-Microbe Interact. 9:323-329, 1996) was highest prior to and during appressorium morphogenesis. PMID:16535630

Buhr, T. L.; Dickman, M. B.

1997-01-01

409

Boule Is Present in Fish and Bisexually Expressed in Adult and Embryonic Germ Cells of Medaka  

PubMed Central

Background The DAZ family genes boule, daz and dazl encode RNA binding proteins essential for fertility of diverse animals including human. dazl has bisexual expression in both mitotic and meiotic germ cells, whereas daz has male premeiotic expression, and boule is largely a unisexual meiotic regulator. Although boule has been proposed as the ancestor for dazl/daz by gene duplication, it has been identified only in invertebrates and mammals. It has, however, remained unclear when and how the DAZ family has evolved in vertebrates. Methodology and Principal Findings This study was aimed at identifying and characterizing the DAZ family genes in fish as the basal vertebrate. We show that boule and dazl coexist in medaka and stickleback. Similar to the medaka dazl (Odazl), the medaka boule (Obol) is maternally supplied and segregates with primordial germ cells. Surprisingly, Obol is expressed in adult germ cells at pre-meiotic and meiotic stages of spermatogenesis and oogenesis. However, the maximal meiotic Obol expression in spermatocytes contrasts with the predominant pre-meiotic Odazl expression in spermatogonia, and the diffuse cytoplasmic Obol distribution in early oocytes contrasts with the Odazl concentration in the Balbinani's body. Conclusions The identification of fish boule and dazl genes provides direct evidence for the early gene duplication during vertebrate evolution. Our finding that Obol exhibits bisexual expression in both embryonic and adult germ cells considerably extends the diversity of boule expression patterns and offers a new insight into the evolutions of DAZ family members, expression patterns and functions in animal fertility. PMID:19564913

Xu, Hongyan; Li, Zhendong; Li, Mingyou; Wang, Li; Hong, Yunhan

2009-01-01

410

The Putative Promoters of Germ Cell-specific Genes and Nanog are Hypomethylated in Chicken Sperm  

PubMed Central

Germ cell-specific genes such as Ddx4, Dnd1, and Dazl play critical roles in the proliferation and survival of germ cells. However, the methylation state of the promoter in mature germ cells is still unknown. Here, we investigated the methylation levels of these genes and the pluripotency marker gene Nanog in chicken sperm as compared with the Alb gene in the liver. CpG islands and/or promoter motifs such as TATA box, GC box and CAAT box were found within the putative promoter regions that we identified. By using the bisulfite reaction, CpG sites in the putative promoters were converted, and they were analyzed by sequencing. The putative promoters of Ddx4, Dnd1, Dazl and Nanog showed very low methylation levels in sperm, but they were highly methylated in the liver. Conversely, the Alb gene promoter was highly methylated in sperm and hypomethylated in the liver. However, no transcripts of Ddx4, Dnd1, Dazl and Nanog were detected in sperm or the liver. Also, no transcripts of Dnmt1 and Dnmt3a were detected in sperm. Our present results may indicate that these germ cell-specific genes and the pluripotency marker gene are ready to express any time after fertilization. Our findings showing that low methylation and selective DNA methylation of specific genes are present in chicken sperm contribute to our understanding of fertilization and embryogenesis of birds. PMID:24632725

KITO, Gakushi; TANAKA, Hiroaki; SOH, Tomoki; YAMAUCHI, Nobuhiko; HATTORI, Masa-aki

2014-01-01

411

TERATOMA WITH MALIGNANT TRANSFORMATION: DIVERSE MALIGNANT HISTOLOGIES ARISING IN MEN WITH GERM CELL TUMORS  

Microsoft Academic Search

PurposeTeratoma with malignant transformation refers to a form of germ cell tumor in which a somatic teratomatous component becomes morphologically malignant and develops aggressive growth. We evaluated the spectrum of histologies, chromosomal abnormalities and clinical outcome in patients with teratoma with malignant transformation.

Robert J. Motzer; Alison Amsterdam; Victor Prieto; Joel Sheinfeld; V. V. V. S. Murty; Madhu Mazumdar; George J. Bosl; R. S. K. Chaganti; Victor E. Reuter

1998-01-01

412

Premeiotic germ cell defect in seminiferous tubules of Atm-null testis  

SciTech Connect

Lifelong spermatogenesis is maintained by coordinated sequential processes including self-renewal of stem cells, proliferation of spermatogonial cells, meiotic division, and spermiogenesis. It has been shown that ataxia telangiectasia-mutated (ATM) is required for meiotic division of the seminiferous tubules. Here, we show that, in addition to its role in meiosis, ATM has a pivotal role in premeiotic germ cell maintenance. ATM is activated in premeiotic spermatogonial cells and the Atm-null testis shows progressive degeneration. In Atm-null testicular cells, differing from bone marrow cells of Atm-null mice, reactive oxygen species-mediated p16{sup Ink4a} activation does not occur in Atm-null premeiotic germ cells, which suggests the involvement of different signaling pathways from bone marrow defects. Although Atm-null bone marrow undergoes p16{sup Ink4a}-mediated cellular senescence program, Atm-null premeiotic germ cells exhibited cell cycle arrest and apoptotic elimination of premeiotic germ cells, which is different from p16{sup Ink4a}-mediated senescence.

Takubo, Keiyo [Department of Cell Differentiation, Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan)]. E-mail: keiyot@gmail.com; Hirao, Atsushi [Division of Molecular Genetics, Department of Molecular Oncology, Cancer Research Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934 (Japan); Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ohmura, Masako [Division of Molecular Genetics, Department of Molecular Oncology, Cancer Research Institute, Kanazawa University, 13-1 Takaramachi, Kanazawa 920-0934 (Japan); Azuma, Masaki [Department of Cell Differentiation, Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Department of Urology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Tokyo 113-8655 (Japan); Arai, Fumio [Department of Cell Differentiation, Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Nagamatsu, Go [Department of Cell Differentiation, Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan); Suda, Toshio [Department of Cell Differentiation, Sakaguchi Laboratory of Developmental Biology, Keio University School of Medicine, 35 Shinano-machi, Shinjuku-ku, Tokyo 160-8582 (Japan)]. E-mail: sudato@sc.itc.keio.ac.jp

2006-12-29

413

In germ cells of mouse embryonic ovaries, the decision to enter meiosis precedes premeiotic DNA replication  

E-print Network

In germ cells of mouse embryonic ovaries, the decision to enter meiosis precedes premeiotic DNA Carpenter2, Dirk G de Rooij3 & David C Page1,2 The transition from mitosis to meiosis is a defining juncture in the life cycle of sexually reproducing organisms. In yeast, the decision to enter meiosis is made before

Carpenter, Anne E.

414

DAZL Limits Pluripotency, Differentiation, and Apoptosis in Developing Primordial Germ Cells  

PubMed Central

Summary The scarcity of primordial germ cells (PGCs) in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade. PMID:25418731

Chen, Hsu-Hsin; Welling, Maaike; Bloch, Donald B.; Muñoz, Javier; Mientjes, Edwin; Chen, Xinjie; Tramp, Cody; Wu, Jie; Yabuuchi, Akiko; Chou, Yu-Fen; Buecker, Christa; Krainer, Adrian; Willemsen, Rob; Heck, Albert J.; Geijsen, Niels

2014-01-01

415

Saudi oncology society and Saudi urology association combined clinical management guidelines for testicular germ cell tumors  

PubMed Central

In this report, updated guidelines for the evaluation, medical, and surgical management of germ cell tumor of testes are resented. They are categorized according the stage of the disease using the tumor-node-metastasis staging system 7th edition. The recommendations are presented with supporting level of evidence. PMID:25371603

Alotaibi, Mohammed; Bazarbashi, Shouki; Alkhateeb, Sultan; Abusamra, Ashraf; Rabah, Danny; Almansour, Mubarak; Murshid, Esam; Alsharm, Abdullah; Ahmad, Imran; Alghamdi, Khalid; Saadeddin, Ahmad; Alghamdi, Abdullah

2014-01-01

416

From testis to teratomas: a brief history of male germ cells in mammals.  

PubMed

In antiquity, many theories were advanced on reproduction and the functions of the gonads. The male genitalia were called "testes" probably from the Latin word "testis" that originally meant "witnesses", because they provide evidence of virility. Through the first dissection of the seminipherous tubules by Renier de Graaf (1668), the discovery of spermatozoa by Antonj van Leeuwenhoek (1677) and in vitro fertilization by Spallanzani (1780) and later by George Newport and George Vines Ellis (1854), it was only in the early part of the XIX century when it was realized that testes produce spermatozoa and that they are essential for egg fertilization and subsequent embryo development. In the period between the end of the XIX and the beginning of the XX century, scientists such as Albert von Kölliker, Franz von Leydig, Enrico Sertoli and Gustaf Retzius (1842-1919) did microscopic observations of testis that marked the history of male germ cells and established the bases for the development of contemporary in vitro culture and molecular studies that are revealing the deeper secrets of male germ cells. Among these, those by Leroy Stevens on embryonal carcinoma cells in the early 1950s led to the present concepts that germ cells and cancer cells share several characteristics and that a close relationship exists between germ cells and stem cells, these being two pillars of modern developmental biology. PMID:23784821

De Felici, Massimo; Dolci, Susanna

2013-01-01

417

Effect of microgravity on primordial germ cells (PGCs) in silk chicken offspring ( Gallus gallus domesticus)  

Microsoft Academic Search

Primordial germ cells (PGCs), precursors of germline cells, display a variety of antigens during their migration to target gonads. Here, we used silk chicken offspring (Gallus gallus domesticus) embryos subjected to space microgravity to investigate the influence of microgravity on PGCs. The ShenZhou-3 unmanned spaceship carried nine fertilized silk chicken eggs, named the flight group, returned to Earth after 7

Zhenming Zhou; Zandong Li

2011-01-01

418

[Regulatory peptides influence on hypoxia induced tooth germ pathology of new born albino rats].  

PubMed

Intrauterine hypoxia decreased the nucleolar organizator quantity in enameloblasts of newborn albino rats tooth germ. Influence the leu-encepgalin synthetic analog dalargin and non-opiate synthetic leu-encephalin on newborn rats from 2 to 6 day abolished the intrauterine hypoxia affect. The main mechanism of peptide antioxidant effect may be NO system stimulation. PMID:21311435

Arsenina, O I; Proskokova, S V; Sazonova, E N

2010-01-01

419

Introduction Germ cells are a highly specialized lineage that is responsible  

E-print Network

. elegans, this cell death is referred to as physiological because the sacrificed nuclei do not seem et al., 1999). Although this suggests that the dying nuclei function in effect as nurse cells a pathway that culls defective germ cell nuclei in response to genotoxic stress (Gartner et al., 2000

Blackwell, Keith

420

Transcriptional Signatures in Response to Wheat Germ Agglutinin and Starvation in Drosophila melanogaster Larval Midgut  

Technology Transfer Automated Retrieval System (TEKTRAN)

One function of plant lectins such as wheat germ agglutinin (WGA) is to serve as defenses against herbivorous insects. The midgut is one critical site affected by dietary lectins. We observed marked cellular, structural, and gene expression changes in the midguts of Drosophila melanogaster third-i...

421

Integration and Germ-Line Transmission of a Pseudotyped Retroviral Vector in Zebrafish  

Microsoft Academic Search

The zebrafish is rapidly becoming a popular model system for the study of vertebrate development because it is ideal for both embryological studies and genetic analysis. To determine if a retroviral vector pseudotyped with the envelope glycoprotein of the vesicular stomatitis virus could infect zebrafish embryos, and in particular, the cells destined to become the germ line, a pseudotyped virus

Shuo Lin; Nicholas Gaiano; Patricia Culp; Jane C. Burns; Theodore Friedmann; Jiing-Kuan Yee; Nancy Hopkins

1994-01-01

422

Biological characteristics of fish germ cells and their application to developmental biotechnology.  

PubMed

We have revealed several unique characteristics of germ cell development using rainbow trout, including the fact that spermatogonia transplanted into the peritoneal cavity of newly hatched embryos migrate toward recipient gonads, that spermatogonia transplanted into female recipients start oogenesis and produce functional eggs and that diploid germ cells transplanted into triploid trout can complete gametogenesis. By combining these unique features of fish germ cells, we established allogeneic and xenogeneic transplantation systems for spermatogonia in several fish species. Spermatogonia isolated from the mature testes of vasa-green fluorescent protein (Gfp) transgenic rainbow trout were transplanted into the peritoneal cavity of triploid masu salmon newly hatched embryos. These spermatogonia migrated toward recipient salmon genital ridges with extending pseudopodia and were subsequently incorporated into them. We further confirmed that the donor-derived spermatogonia resumed gametogenesis and produced sperm and eggs in male and female salmon recipients, respectively. By inseminating the resulting eggs and sperm, we obtained only rainbow trout offspring in the F1 generation, suggesting that the triploid salmon recipients produced functional gametes derived only from donor trout. We further confirmed that this intra-peritoneal transplantation of germ cells is applicable to several marine fishes, which could be of benefit in the production of bluefin tuna that has a large broodstock (>100 kg) and is difficult to maintain in captivity. Gamete production of bluefin tuna could be more easily achieved by generating a surrogate species, such as mackerel, that can produce tuna gametes. PMID:22827369

Yoshizaki, G; Okutsu, T; Morita, T; Terasawa, M; Yazawa, R; Takeuchi, Y

2012-08-01

423

Developmental control of sumoylation pathway proteins in mouse male germ cells  

Microsoft Academic Search

Protein sumoylation regulates a variety of nuclear functions and has been postulated to be involved in meiotic chromosome dynamics as well as other processes of spermatogenesis. Here, the expression and distribution of sumoylation pathway genes and proteins were determined in mouse male germ cells, with a particular emphasis on prophase I of meiosis. Immunofluorescence microscopy revealed that SUMO1, SUMO2\\/3 and

Sophie La Salle; Fengyun Sun; Xiang-Dong Zhang; Michael J. Matunis; Mary Ann Handel

2008-01-01

424

Fermented Wheat Germ Extract (Avemar) in the Treatment of Cancer and Autoimmune Diseases  

Microsoft Academic Search

Avemar, the product of industrial fermentation of wheat germ, possesses unique cancer-fighting characteristics. Taken orally, Avemar can inhibit metastatic tumor dissemination and proliferation during and after chemotherapy, surgery, or radiation. Benefits of Avemar treatment have been shown in various human cancers, in cultures of in vitro grown cancer cells, in the prevention of chemical carcinogenesis, and also in some autoimmune

LASZLO G. BOROS; MICHELE NICHELATTI; YEHUDA SHOENFELDc

2005-01-01

425

Studies on the nutraceuticals composition of wheat derived oils wheat bran oil and wheat germ oil.  

PubMed

Fat-soluble nutraceuticals of cereals are known for number of disease preventive activities. Hence wheat bran oil (WBO) and wheat germ oil (WGO) were extracted from wheat bran and germ which yielded 3.35 % and 7.35 % of oil, containing polyunsaturated fatty acids (PUFA) (64 %, 61.2 %) respectively. Both oils contained tocopherols and carotenoids, which were higher in wheat germ oil (273 mg/100 g, 12.23 mg/100 g) than wheat bran oil (190 mg/100 g, 2.21 mg/100 g). Steryl ferulates were also present in both the oils, but their content was eight-fold higher in WBO than in WGO. Three major steryl ferulates identified by HPLC were campesteryl ferulate and sitostenyl ferulate, campestanyl ferulate and ?-sitosteryl ferulate as in ?-oryzanol and another ferulate, viz., sitostanyl ferulate. A strong IC50 value of 7.5 mg/mL and 21.6 mg/mL DPPH free radicals scavenging for wheat germ oil for wheat bran oil was observed. NMR ((13)C and (1)H) profile explored the evidence of distribution of antioxidant molecules in the unsaponifiable matter of wheat derived oil. Since oils rich in PUFA and minor components are required for the normal physiological activities, blending such oils with other edible oils of the diet in wheat growing countries like India may be useful to provide health benefits. PMID:25694731

Kumar, G Suresh; Krishna, A G Gopala

2015-02-01

426

The development of a "Green" aqueous enzymatic process to extract corn oil from corn germ  

Technology Transfer Automated Retrieval System (TEKTRAN)

Approximately 2.4 million tons of commercial corn oil were produced worldwide in 2012, compared to 2012 world production of palm oil (53.3 MT) and soybean oil (43.1 MT) according to FAS, USDA. Most commercial corn oil (~90%) is produced from corn germ that is expeller pressed and/or hexane extracte...

427

Wheat germ oil in larval diet influences gene expression in adult oriental fruit fly  

Technology Transfer Automated Retrieval System (TEKTRAN)

Culture media supplemented with wheat germ oil (WGO) exerts observable physiological reactions, such as increased fecundity and mobility, in some insects. Although the impact of WGO on insect physiology is important, the mechanisms of these actions are poorly understood. The hypothesis that the ad...

428

Testicular Mixed Germ Cell Tumor in an Adolescent with Cowden Disease  

Microsoft Academic Search

Cowden disease (also known as Cowden syndrome) is characterized by multiple organ hamartomatous tumors and an increased risk of malignancy, in particular of the breast, thyroid and endometrium. Testicular tumors including seminoma have previously been reported in adult patients. We are reporting, for the first time, a case of testicular mixed germ cell tumor in an adolescent with Cowden disease.

Minati Devi; Norma Leonard; Svetlana Silverman; Mohamed Al-Qahtani; Rose Girgis

2007-01-01

429

Germ-cell nondisjunction in testes biopsies of men with idiopathic infertility.  

PubMed Central

Intracytoplasmic sperm injection (ICSI) has been used in combination with testicular sperm extraction to achieve pregnancies in couples with severe male-factor infertility, yet many of the underlying genetic mechanisms remain largely unknown. To investigate nondisjunction in mitotic and meiotic germ cells, we performed three-color FISH to detect numeric chromosome aberrations in testicular tissue samples from infertile men confirmed to have impaired spermatogenesis of unknown cause. FISH was employed to determine the rate of sex-chromosome aneuploidy in germ cells. Nuclei were distinguished as haploid or diploid, respectively. The overall incidence of sex-chromosome aneuploidy in germ cells was found to be significantly higher (P<.00001) in all three abnormal histopathologic patterns (range 39.0%-43.5%) as compared with normal controls (29.1%). The relative ratio of normal to aneuploid nuclei in the diploid cells of patients with impaired spermatogenesis was approximately 1.0, a >300% decrease when compared with the 4.42 ratio detected in patients with normal spermatogenesis. These results provide direct evidence of an increased incidence of sex-chromosome aneuploidy observed in germ cells of men with severely impaired spermatogenesis who might be candidates for ICSI with sperm obtained directly from the testis. The incidence of aneuploidy was significantly greater among the diploid nuclei, which suggests that chromosome instability is a result of altered genetic control during mitotic cell division and proliferation during spermatogenesis. PMID:10330350

Huang, W J; Lamb, D J; Kim, E D; de Lara, J; Lin, W W; Lipshultz, L I; Bischoff, F Z

1999-01-01

430

Ovarian malignant mixed germ cell tumor with clear cell carcinoma in a postmenopausal woman  

PubMed Central

Malignant germ cell tumors of the ovary are very rare and account for about 2-5% of all ovarian tumors of germ origin. Most patients are adolescent and young women, approximately two-thirds of them are under 20 years of age, occasionally in postmenopausal women. But clear cell carcinoma usually occurs in older patients (median age: 57-year old), and closely related with endometriosis. Here we report a case of a 55-year old woman with right ovarian mass that discovered by B ultrasonic. Her serum levels of human chorionic gonadotropin (hCG) and ?-fetoprotein (AFP) were elevated. Pathological examination revealed the tumor to be a mixed germ cell tumor (yolk sac tumor, embryonal carcinoma and mature teratoma) with clear cell carcinoma in a background of endometriosis. Immunohistochemical staining showed SALL4 and PLAP were positive in germ cell tumor area, hCG, CD30 and OCT4 were positive in epithelial-like cells and giant synctiotrophoblastic cells, AFP, AAT, CD117 and Glyp3 were positive in yolk sac component, EMA and CK7 were positive in clear cell carcinoma, CD10 was positive in endometrial cells of endometriotic area. She was treated with surgery followed by seven courses of chemotherapy. She is well and serum levels of hCG and AFP have been decreased to normal levels. PMID:25674278

Yu, Xiu-Jie; Zhang, Lin; Liu, Zai-Ping; Shi, Yi-Quan; Liu, Yi-Xin

2014-01-01

431

The comet assay as an indicator test for germ cell genotoxicity.  

PubMed

The in vivo comet assay is a well-established genotoxicity test. It is currently mainly performed with somatic cells from different organs to detect a genotoxic activity of potential carcinogens. It is regarded as a useful test for follow-up testing of positive or equivocal in vitro test results and for the evaluation of local genotoxicity. However, the comet assay also has the potential to detect germ cell genotoxicity and may be used for demonstrating the ability of a substance or its metabolite(s) to directly interact with the genetic material of gonadal and/or germ cells. Such results are important for the classification of germ cell mutagens, e.g. in the context of the "Globally Harmonized System of Classification and Labelling of Chemicals" (GHS). This review summarizes and discusses available information on the use of the comet assay with germ cells and cells from the gonads in genetic toxicology. The literature contains results from in vitro studies, ex vivo studies and in vivo studies. With regard to the assessment of germ cell genotoxicity, only in vivo studies are relevant but the other kind of studies provided important information on various aspects of the methodology. Many comet assay studies with human sperm have been performed in the context of male infertility and assisted fertilization. The results of these studies are not reviewed in detail here but various aspects of the assay modifications used are discussed. Measuring DNA effects by the comet assay in sperm requires additional steps for chromatin decondensation. Many different modifications of the alkaline and the neutral comet assay are in use but a standard protocol has not been established yet. High and variable background levels of DNA effects were reported and there is still need for standardization and validation of the comet assay with sperm. Some human biomonitoring studies with human sperm were published, but it seems to be premature to use these data for hazard identification and classification of chemicals. In contrast, the standard alkaline in vivo comet assay can easily be adapted to investigations with cells from reproductive organs. Tests with cells from the gonads (testis and ovary) seem to be most appropriate and a promising tool for demonstrating that a test compound reaches the gonads and is able to interact with the genetic material of germ cells. However, studies to standardize and validate these methods are necessary before the comet assay can be usefully applied in risk assessment of germ cell mutagens. PMID:18462987

Speit, Günter; Vasquez, Marie; Hartmann, Andreas

2009-01-01

432

Glycerol-3-Phosphate Acyltransferase-2 Is Expressed in Spermatic Germ Cells and Incorporates Arachidonic Acid into Triacylglycerols  

PubMed Central

Background De novo glycerolipid synthesis begins with the acylation of glycerol-3 phosphate catalyzed by glycerol-3-phosphate acyltransferase (GPAT). In mammals, at least four GPAT isoforms have been described, differing in their cell and tissue locations and sensitivity to sulfhydryl reagents. In this work we show that mitochondrial GPAT2 overexpression in CHO-K1 cells increased TAG content and both GPAT and AGPAT activities 2-fold with arachidonoyl-CoA as a substrate, indicating specificity for this fatty acid. Methods and Results Incubation of GPAT2-transfected CHO-K1 cells with [1-14C]arachidonate for 3 h increased incorporation of [14C]arachidonate into TAG by 40%. Consistently, arachidonic acid was present in the TAG fraction of cells that overexpressed GPAT2, but not in control cells, corroborating GPAT2's role in synthesizing TAG that is rich in arachidonic acid. In rat and mouse testis, Gpat2 mRNA was expressed only in primary spermatocytes; the protein was also detected in late stages of spermatogenesis. During rat sexual maturation, both the testicular TAG content and the arachidonic acid content in the TAG fraction peaked at 30 d, matching the highest expression of Gpat2 mRNA and protein. Conclusions These results strongly suggest that GPAT2 expression is linked to arachidonoyl-CoA incorporation into TAG in spermatogenic germ cells. PMID:22905194

Rabassa, Martin E.; Lacunza, Ezequiel; Coleman, Rosalind A.; Gonzalez-Baro, Maria R.

2012-01-01

433

Inter-Regional, Epidemiological Study of Childhood Cancer (IRESCC): case-control study in children with germ cell tumors  

SciTech Connect

In 1980-1983 members of IRESCC interviewed parents of 555 children with newly diagnosed cancer on topics of possible etiological significance. Identical questions were asked of the parents of 1100 control children chosen from hospital admissions and general practitioner lists. Medical information was confirmed whenever possible by cross-checking with NHS records. Data for the 41 children with germ cell tumors and their 82 controls are reported here. The cases had more major congenital malformations than controls, including one neural tube defect. More case than control mothers and fathers reported occupational exposure to chemicals. Nine close relatives of cases had multiple primary tumors, which were often benign or of low-grade malignancy, compared with 1 hospital control and 3 general practitioner control relatives. Cases and controls differed with respect to birth weight and paternal age. No case-control differences were shown for: birth rank, maternal age, chronic illnesses and smoking, mothers reproductive histories and oral contraceptive usage. In index pregnancies there were no case-control differences for maternal illness, infections, alcohol intake and X-ray and ultrasound exposure. There was no difference between cases and controls for the frequency of twinning the families.

Johnston, H.E.; Mann, J.R.; Williams, J.; Waterhouse, J.A.; Birch, J.M.; Cartwright, R.A.; Draper, G.J.; Hartley, A.L.; McKinney, P.A.; Hopton, P.A.