Search Results
Results 401 - 450 of 2063
< 4 5 6 7 8 9 10 11 12 13 14 >
Ponniah Gomathinayagam - - 2007
Candida albicans utilizes mammalian cell-associated transglutaminase (TGase) activity to adhere covalently to human buccal epithelial cells (BECs) through Hyphal Wall Protein 1. Little is known about the factors leading to the identity and appearance of Hwp1 binding partners on cells lining the oral cavity. The observation that BECs vary in ...
Cheng L - - 2007
A residual retroperitoneal mass containing only fibrosis and necrosis is present in 40-52% of patients with advanced testicular germ cell tumours after chemotherapy. The biological nature and genetic characteristics of the stromal cells in these residual masses have not been adequately investigated. Laser-microdissected stromal cells from 27 patients who underwent ...
Söder Olle - - 2007
Sexual dimorphism is a term describing morphological differences between the sexes, but is often extended to include all differences observed between females and males. Sex differentiation in vertebrates is by definition sexually dimorphic and starts at the level of the sex chromosomes. In this review the sexual dimorphism of gonadal ...
Knoll John Gabriel JG Department of Biomedical Sciences, Colorado State University, 1617 Campus Delivery, Fort Collins, CO 80523, - - 2007
The preoptic area-anterior hypothalamus (POA-AH) is characterized by sexually dimorphic features in a number of vertebrates and is a key region of the forebrain for regulating physiological responses and sexual behaviours. Using live-cell fluorescence video microscopy with organotypic brain slices, the current study examined sex differences in the movement characteristics ...
Vrtovec Katja Triller - - 2007
This article argues that totipotent character of human totipotent cells--defined as the capacity of a cell "to differentiate into all somatic lineages (ectoderm, mesoderm, endoderm), the germ line and extra-embryonic tissues such as the placenta"--is not a sufficient reason to exclude their patentability on the basis of Article 5(1) of ...
Bowles Josephine - - 2007
Although mammalian sex is determined genetically, the sex-specific development of germ cells as sperm or oocytes is initiated by cues provided by the gonadal environment. During embryogenesis, germ cells in an ovary enter meiosis, thereby committing to oogenesis. By contrast, germ cells in a testicular environment do not enter meiosis ...
Miura Chiemi - - 2007
Using two species of teleost fish, Japanese huchen (Hucho perryi) and common carp (Cyprinus carpio), we investigated whether sex steroids are involved in early oogenesis in vitro. Ovarian fragments were cultured to examine the effects of a progestin, 17alpha, 20beta-dihydroxy-4-pregnen-3-one (DHP), and an estrogen, estradiol-17 beta (E2). DHP and E2 ...
Nakada Tsutomu - - 2007
Members of the Rh glycoprotein family have been shown to be involved in ammonia transport in a variety of species. Here we show that zebrafish Rhcg1, a member of the Rh glycoprotein family, is highly expressed in the yolk sac, gill, and renal tubules. Molecular cloning and characterization indicate that ...
Saito Daisuke - - 2007
The proliferation of germ cells becomes sexually dimorphic during gonadal sex differentiation, although the underlying dynamics of this are not well understood in vertebrates. By tracing GFP-labeled germ cells in vivo and analyzing the germ cell-depleted mutant, zenzai, we show that the proliferation and differentiation of germ cells are regulated ...
Oosterhuis J Wolter - - 2007
Hypotheses on the origin and distribution of extragonadal germ cell tumours (GCTs) and teratomas are briefly reviewed and revisited in the light of (i) new developments in the classification of GCTs, (ii) data on genomic imprinting of these neoplasms and (iii) the recent finding that germ cells can be derived ...
de Jong Jeroen - - 2007
The JKT-1 cell line has been used in multiple independent studies as a representative model of human testicular seminoma. However, no cell line for this specific tumour type has been independently confirmed previously; and therefore, the seminomatous origin of JKT-1 must be proven. The genetic constitution of the JKT-1 cells ...
Jung Anita - - 2007
The essential gene noa (CG 3971; also known as Baldspot) encodes a very long chain fatty acid elongase which is most similar to the mammalian elongase ELOVL6. noa is expressed in the nervous system from embryogenesis on, in imaginal discs, the fat body, malpighian tubules and in the gonads of ...
Cortés-Gutiérrez Elva I - - 2008
Constitutive alkali-labile sites (ALSs) have been investigated using a protocol of DNA breakage detection-fluorescence in situ hybridization (DBD-FISH) in sperm cells from Sus domesticus (pig), Ovis gmelini musimon (mouflon) and Ovis aries (sheep). The results were compared with those obtained using leucocytes from the same species. Whole comparative genomic hybridization ...
Sarkar Angshuman - - 2007
The capacity of stem cells to self renew and the ability of stem cell daughters to differentiate into highly specialized cells depend on external cues provided by their cellular microenvironments [1-3]. However, how microenvironments are shaped is poorly understood. In testes of Drosophila melanogaster, germ cells are enclosed by somatic ...
Zanetti Samanta R - - 2007
Doxorubicin disrupts spermatogenesis by causing apoptosis of spermatogonia and primary spermatocytes. The aim of this study was to examine the effect of this agent on adult rat testicular lipids and their fatty acids. A single dose (7.5 mg/kg) and a multidose regime (3 mg/kg once a week for 4 weeks) ...
Iwahashi Kazuhiro - - 2007
In mice, unique events regulating epigenetic programming (e.g., genomic imprinting) and replication state (mitosis versus meiosis) occur during fetal germ cell development. To determine whether these processes are autonomously programmed in fetal germ cells or are dependent upon ongoing instructive interactions with surrounding gonadal somatic cells, we isolated male and ...
Aramaki Shinya - - 2007
Chicken primordial germ cells (PGCs) dynamically migrate towards the prospective gonadal area through the germinal crescent region and bloodstream at early embryonic stages. To date, chicken PGCs have been mainly identified by histochemical and immunohistochemical methods or by their morphological characteristics. However, their origin, migration and differentiation are not fully ...
Baker Catherine C - - 2007
Translational control is crucial for proper timing of developmental events that take place in the absence of transcription, as in meiotic activation in oocytes, early embryogenesis in many organisms, and spermatogenesis. Here we show that a novel form of the translation initiation complex component eIF4G in Drosophila, eIF4G2, is required ...
Franklin-Dumont Tina M - - 2007
During spermatogenesis, cells coordinate differentiation with the meiotic cell cycle to generate functional gametes. We identified a novel gene, which we named off-schedule (ofs), as being essential for this coordinated control. During the meiotic G(2) phase, Drosophila ofs mutant germ cells do not reach their proper size and fail to ...
Yeung C H - - 2007
OBJECTIVE: To understand the clinical significance of immature germ cells commonly found in ejaculates with low sperm counts by a novel and stringent flow cytometric quantitative method. PATIENTS/MEASUREMENTS: A total of 65 azoospermic, 38 cryptozoospermic and 42 severe oligozoospermic patients underwent routine hormone and semen analysis. Cells from each ejaculate ...
Li Chun-Yan - - 2007
Elucidating the regulatory mechanism of cell proliferation is central to the understanding of cancer development or organ size control. Drosophila spermatogenesis provides an excellent model to study cell proliferation since the germline cells mitotically amplify in a precise manner. However, the underlying molecular mechanism remains elusive. Germ cells derived from ...
Zheng Ping - - 2007
Although cell-autonomous genetic programs pursued by germ and somatic cells are of critical import, intimate interplays between the two cell types are also essential for normal development of the female gonad. Recent studies demonstrate that oocytes play active roles in coordinating the growth and differentiation of somatic cells during folliculogenesis ...
Wajner Simone Magagnin - - 2007
The testis has been classically described as a thyroid hormone unresponsive tissue, but recent studies indicate that these hormones might play an important role in developing testes. We have previously demonstrated that type 2 iodothyronine deiodinase (D2), a thyroid hormone-activating enzyme, is expressed in adult rodent testis and that its ...
Tachibana Makoto - - 2007
Histone H3 lysine 9 (H3K9) methylation is a crucial epigenetic mark of heterochromatin formation and transcriptional silencing. G9a is a major mammalian H3K9 methyltransferase at euchromatin and is essential for mouse embryogenesis. Here we describe the roles of G9a in germ cell development. Mutant mice in which G9a is specifically ...
Herrid Muren - - 2007
Although methods to assess testis cell populations are established in mice, the detailed validation of similar methods for bovine testis cells is necessary for the development of emerging technologies such as male germ cell transplantation. As young calves provide donor cells for germ cell transplantation, we characterized cell populations from ...
Ikenishi Kohji - - 2007
Whether all descendants of germline founder cells inheriting the germ plasm can migrate correctly to the genital ridges and differentiate into primordial germ cells (PGCs) at tadpole stage has not been elucidated in Xenopus. We investigated precisely the location of descendant cells, presumptive primordial germ cells (pPGCs) and PGCs, in ...
MacLean Glenn - - 2007
Cyp26b1 encodes a retinoic acid (RA) metabolizing cytochrome P450 enzyme that is expressed in embryonic tissues undergoing morphogenesis, including the testes. We have generated transgenic mice lacking Cyp26b1 and have observed increased RA levels in embryonic testes. Cyp26b1(-/-) germ cells prematurely enter meiosis at embryonic d 13.5 and appear to ...
Lei Ning N Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas 66160, - - 2007
Immunohistochemistry was used to examine GCNA1, a germ cell-specific protein, together with DMRT1 (Doublesex and Mab-3-related transcription factor-1), a transcription factor implicated in Sertoli cell and germ cell function, in order to resolve DMRT1's cellular profile during pre- and postnatal gonad development in the mouse. In the indifferent gonad (10.5-11.5 ...
Zayed A E - - 2007
The prenatal differentiation of male and female gonads of the mouse was investigated both morphologically and immunohistochemically. Sexual dimorphism could be detected as early as 12 days post-coitum (dpc) by the appearance of the primary elements of the tunica albuginea and positive immunoreactivity for anti-Muellerian hormone in the Sertoli cells ...
Nishikawa Shin-Ichi - - 2007
The cell biology of the early processes of mammalian embryogenesis, such as germ-layer formation, has been technically challenging to study owing to the size and accessibility of mammalian embryos. Embryonic stem cells, which can generate the three germ layers in vitro, are useful for studying embryogenesis at the cellular level. ...
Zhang Jianhong - - 2007
In different species of mammal, uterine natural killer (uNK) cells are massively recruited and presented at the fetal maternal interface with a spatio-temporal pattern, and regarded as a constructive element to support reproductive development. Recent insights highlight the uNK cells activation, function and interaction with local compartments, which all contribute ...
Pépin David - - 2007
Chromatin has emerged as an important regulator of gene expression, interposed between cell signaling pathways and transcriptional machinery. It participates in transmitting extra- and intra-cellular signals that coordinate ovarian events: ovarian follicle development, the meiotic maturation of the oocyte that precedes ovulation, and the ovulatory process and consequent luteinization. Recent ...
Pareek Tej K - - 2007
The role of pituitary gonadotropins in the regulation of spermatogenesis has been unequivocally demonstrated, although, the precise mechanism of this regulation is not clearly understood. Previous studies have shown that specific immunoneutralization of LH/testosterone caused apoptotic cell death of meiotic and post-meiotic germ cells while that of FSH resulted in ...
Qi Aladaer - - 2008
Mammalian germ cells proliferate by mitosis and begin meiotic development in fetal ovaries. The aim of this study is to demonstrate the germ cell proliferation and apoptosis, and elucidated some of the key developmental events and stages in Mongolian sheep fetal ovaries. Fourty three pairs of sheep fetal ovaries at ...
Wolke Uta U Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, - - 2007
Oocytes in the C. elegans gonad enlarge rapidly. During the stage of enlargement, they are transcriptionally quiescent, and it is not understood how they acquire large quantities of materials such as mRNA and protein. Enlarging oocytes are connected via cytoplasmic bridges to a large, younger population of transcriptionally active germ ...
Ihara Shinji - - 2007
Members of the ADAMTS (a disintegrin and metalloprotease with thrombospondin motifs) family of secreted proteins play important roles in animal development and pathogenesis. However, the lack of in vivo models has hampered elucidation of the mechanisms by which these enzymes are recruited to specific target tissues and the timing of ...
PENKALA, JOSEPH EDWARD
During normal embryogenesis in Rana pipiens the primordial germ cells (PGCs) undergo a displacement from deep within the ventral endoderm of the Stage 17 tailbud embryo to the dorsal endodermal crest of the hatched Stage 20 larva; eventually they exit the endoderm and populate the paired gonadal primordia. This study ...
Surani M Azim - - 2007
The pluripotent epiblast cells in the early embryo are destined to form both the somatic cells and primordial germ cells. In the few cells that undergo specification to establish the germ cell lineage, there is repression of the somatic programme. Recent evidence shows that, Blimp1, a known transcriptional repressor with ...
Wilson Stephen - - 2007
Selective microbial colonisation of germ-free piglets is reported to result in expansion of immunoglobulin V(H)- and D(H)-segment usage from an initially limited repertoire. Here, the response of the palatine tonsil to microbial colonisation was compared in age-matched conventionally reared and germ-free piglets. At 3 and 5 days after birth an ...
Kim Shinseog - - 2007
Genes containing the DM domain, a conserved DNA binding motif first found in Doublesex of Drosophila and mab-3 of Caenorhabditis elegans, regulate sexual differentiation in multiple phyla. The DM domain gene Dmrt1 is essential for testicular differentiation in vertebrates. In the mouse, Dmrt1 is expressed in pre-meiotic germ cells and ...
Wolski Katja M - - 2007
AIM: To determine the effectiveness of the sk11, sk9 and sk11 TNUA5 Sertoli cell lines in binding germ cells in vitro. METHODS: The immortalized Sertoli cell lines sk9, sk11 and sk11 TNUA5 were used in co-culture experiments with germ cells in media with or without reproductive hormones and incubated for ...
Boldajipour Bijan - - 2007
Cell differentiation, cell proliferation, cell death, and cell migration are tightly controlled during animal development and adult homeostasis. Failure to regulate these processes can result in tumor formation and metastasis. Aberrant cells are therefore often cleared by induction of cell death. Recent work has elucidated the mechanism of elimination of ...
Adler Elizabeth M - - 2007
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 ...
Kimble Judith - - 2007
Animal germ cells differentiate as sperm or eggs, depending on their sex. Somatic signals tell germ cells whether they reside in a male or female body, but how do germ cells interpret those external cues to acquire their own sexual identity? A critical aspect of a germ cell's sexual puzzle ...
Strome Susan - - 2007
The early embryo is formed by the fusion of two germ cells that must generate not only all of the nonreproductive somatic cell types of its body but also the germ cells for the next generation. Therefore, embryo cells face a crucial decision: whether to develop as germ or soma. ...
Furland Natalia E - - 2007
The aim of the present study was to examine the effects of experimental cryptorchidism on rat testicular phospholipids and neutral lipids that contain long-chain (C(18)-C(22)) and very long-chain (VLC) (C(24)-C(32)) polyunsaturated fatty acids (PUFA). The weight of the cryptorchid testis was nearly half that of the contralateral control at postsurgical ...
Houwing Saskia - - 2007
Piwi proteins specify an animal-specific subclass of the Argonaute family that, in vertebrates, is specifically expressed in germ cells. We demonstrate that zebrafish Piwi (Ziwi) is expressed in both the male and the female gonad and is a component of a germline-specifying structure called nuage. Loss of Ziwi function results ...
Deshpande Girish - - 2007
The primitive embryonic gonad in Drosophila melanogaster is composed of germ cells and somatic gonadal precursor cells (SGPs). The assembly of a functional gonad involves a complex series of germ-cell migration events, which are thought to be guided by attractive and repulsive cues. Here, we demonstrate a novel role for ...
Neuhaus Birger - - 2007
The protonephridial system of several Loricifera was studied by transmission electron microscopy. A larval specimen of Rugiloricus cf. cauliculus possesses two protonephridia, which are "capped" frontally by a compact mass of still undifferentiated gonadal cells. Each protonephridium consists of four monociliary terminal cells and four canal cells with a diplosome ...
Islam M Q - - 2007
Embryonic stem (ES) cells are potential sources of tissue regeneration; however, transplanted ES cells produce tumors in the host tissues. In addition, transplantation between genetically unrelated individuals often results in graft rejection. Although the development of patient specific stem cell lines by somatic cell nuclear transfer (SCNT) represents a means ...
< 4 5 6 7 8 9 10 11 12 13 14 >