Chromatin

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Chromatin

  • condensed chromatin
  • nuclear chromatin
  • sperm chromatin

  • Terms modified by Chromatin

  • chromatin change
  • chromatin condensation
  • chromatin conformation
  • chromatin domain
  • chromatin dynamics
  • chromatin immunoprecipitation
  • chromatin immunoprecipitation analysis
  • chromatin modification
  • chromatin modifications
  • chromatin organization
  • chromatin packaging
  • chromatin pattern
  • chromatin protein
  • chromatin regulation
  • chromatin remodeling
  • chromatin remodeling factor
  • chromatin remodelling
  • chromatin structure

  • Selected Abstracts


    O-12 BLAND DYSKARYOSIS: A NEW PITFALL IN THINPREP® LIQUID BASED CYTOLOGY

    CYTOPATHOLOGY, Issue 2006
    M. A. Lynch
    Liquid based cytology (LBC) has improved cell visualization and preservation in cervical cytology. There has been a reduction in inadequate rate and some data to suggest an increase in sensitivity for dyskaryosis. Training for LBC has focused on differences in distribution of abnormal cells, but in most cases the morphological appearance of the dyskaryotic cells themselves is similar to that seen in conventional cytology. We are describing a new presentation of dyskaryosis which may be a cause of false negative cytology. We have referred to this as ,Bland dyskaryosis' because cells appear deceptively bland on low power examination, and can be misinterpreted as metaplastic or endocervical cells. Bland dyskaryosis cells are seen in groups. The architecture of the group is very disorganized, and adjacent cells show variation in size. Cells have a high nuclear/cytoplasmic ratio and smooth nuclear membranes. Chromatin is finely granular and evenly distributed. This is an unusual presentation of high-grade dyskaryosis and we feel that there is a learning curve in laboratories converting to liquid based cytology. The spectrum of appearances of squamous dyskaryosis needs to be delineated to allow further increases in sensitivity for dyskaryosis. [source]


    Chromatin immunoprecipitation-mediated target identification proved aquaporin 5 is regulated directly by estrogen in the uterus

    GENES TO CELLS, Issue 10 2006
    Mika Kobayashi
    Estrogens play a central role in the reproduction of vertebrates and affect a variety of biological processes. The major target molecules of estrogens are nuclear estrogen receptors (ERs), which have been studied extensively at the molecular level. In contrast, our knowledge of the genes that are regulated directly by ERs remains limited, especially at the level of the whole organism rather than cultured cells. In order to identify genes that are regulated directly by ERs in vivo, we used estrogen treated mouse uterus and performed chromatin immunoprecipitation. Sequence analysis of a precipitated DNA fragment enabled alignment with the mouse genomic sequence and revealed that the promoter region of the gene encoding aquaporin 5 (AQP5) was precipitated with antibody against ER,. Quantitative PCR and DNA microarray analyses confirmed that AQP5 is activated soon after administration of estrogen. In addition, the promoter region of AQP5 contained a functional estrogen response element that was activated directly by estrogen. Although several AQP genes are expressed in the uterus, only direct activation of AQP5 could be detected following treatment with estrogen. This chromatin immunopreciptation-mediated target identification may be applicable to the study of other transcription factor networks. [source]


    In Vitro Compaction of Germinal Vesicle Chromatin is Beneficial to Survival of Vitrified Cat Oocytes

    REPRODUCTION IN DOMESTIC ANIMALS, Issue 2009
    P Comizzoli
    Contents The immature cat oocyte contains a large-sized germinal vesicle (GV) with decondensed chromatin that is highly susceptible to cryo-damage. The aim of the study was to explore an alternative to conventional cryopreservation by examining the influence of GV chromatin compaction using resveratrol (Res) exposure (a histone deacetylase enhancer) on oocyte survival during vitrification. In Experiment 1, denuded oocytes were exposed to 0, 0.5, 1.0 or 1.5 mmol/l Res for 1.5 h and then evaluated for chromatin structure or cultured to assess oocyte meiotic and developmental competence in vitro. Exposure to 1.0 or 1.5 mmol/l Res induced complete GV chromatin deacetylation and the most significant compaction. Compared to other treatments, the 1.5 mmol/l Res concentration compromised the oocyte ability to achieve metaphase II (MII) or to form a blastocyst. In Experiment 2, denuded oocytes were exposed to Res as in Experiment 1 and cultured in vitro either directly (fresh) or after vitrification. Both oocyte types then were assessed for meiotic competence, fertilizability and ability to form embryos. Vitrification exerted an overall negative influence on oocyte meiotic and developmental competence. However, ability to reach MII, achieve early first cleavage, and develop to an advanced embryo stage (8,16 cells) was improved in vitrified oocytes previously exposed to 1.0 mmol/l Res compared to all counterpart treatments. In summary, results reveal that transient epigenetic modifications associated with GV chromatin compaction induced by Res is fully reversible and beneficial to oocyte survival during vitrification. This approach has allowed the production of the first cat embryos from vitrified immature oocytes. [source]


    Chromatin dynamics of unfolding and refolding controlled by the nucleosome repeat length and the linker and core histones

    BIOPOLYMERS, Issue 4 2007
    Toshiro Kobori
    Abstract Chromatin is composed of genomic DNA and histones, forming a hierarchical architecture in the nucleus. The chromatin hierarchy is common among eukaryotes despite different intrinsic properties of the genome. To investigate an effect of the differences in genome organization, chromatin unfolding processes were comparatively analyzed using Schizosaccaromyces pombe, Saccharomyces cerevisiae, and chicken erythrocyte. NaCl titration showed dynamic changes of the chromatin. 400,1000 mM NaCl facilitated beads with ,115 nm in diameter in S. pombe chromatin. A similar transition was also observed in S. cerevisiae chromatin. This process did not involve core histone dissociation from the chromatin, and the persistence length after the transition was ,26 nm for S. pombe and ,28 nm for S. cerevisiae, indicating a salt-induced unfolding to "beads-on-a-string" fibers. Reduced salt concentration recovered the original structure, suggesting that electrostatic interaction would regulate this discrete folding-unfolding process. On the other hand, the linker histone was extracted from chicken chromatin at 400 mM NaCl, and AFM observed the "beads-on-a-string" fibers around a nucleus. Unlike yeast chromatin, therefore, this unfolding was irreversible because of linker histone dissociation. These results indicate that the chromatin unfolding and refolding depend on the presence and absence of the linker histone, and the length of the linker DNA. © 2007 Wiley Periodicals, Inc. Biopolymers 85:295,307, 2007. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]


    Immune subversion by chromatin manipulation: a ,new face' of host,bacterial pathogen interaction

    CELLULAR MICROBIOLOGY, Issue 8 2008
    Laurence Arbibe
    Summary Bacterial pathogens have evolved various strategies to avoid immune surveillance, depending of their in vivo,lifestyle'. The identification of few bacterial effectors capable to enter the nucleus and modifying chromatin structure in host raises the fascinating questions of how pathogens modulate chromatin structure and why. Chromatin is a dynamic structure that maintains the stability and accessibility of the host DNA genome to the transcription machinery. This review describes the various strategies used by pathogens to interface with host chromatin. In some cases, chromatin injury can be a strategy to take control of major cellular functions, such as the cell cycle. In other cases, manipulation of chromatin structure at specific genomic locations by modulating epigenetic information provides a way for the pathogen to impose its own transcriptional signature onto host cells. This emerging field should strongly influence our understanding of chromatin regulation at interphase nucleus and may provide invaluable openings to the control of immune gene expression in inflammatory and infectious diseases. [source]


    Syndromes of disordered chromatin remodeling

    CLINICAL GENETICS, Issue 2 2003
    J Ausió
    Syndromes of disordered ,chromatin remodeling' are unique in medicine because they arise from a general deregulation of DNA transcription caused by mutations in genes encoding enzymes which mediate changes in chromatin structure. Chromatin is the packaged form of DNA in the eukaryotic cell. It consists almost entirely of repeating units, called nucleosomes, in which short segments of DNA are wrapped tightly around a disk-like structure comprising two subunits of each of the histone proteins H2A, H2B, H3 and H4. Histone proteins are covalently modified by a number of different adducts (i.e. acetylation and phosphorylation) that regulate the tightness of the DNA,histone interactions. Mutations in genes encoding enzymes that mediate chromatin structure can result in a loss of proper regulation of chromatin structure, which in turn can result in deregulation of gene transcription and inappropriate protein expression. In this review we present examples of representative genetic diseases that arise as a consequence of disordered chromatin remodeling. These include: ,-thalassemia/mental retardation syndrome, X-linked (ATR,X); Rett syndrome (RS); immunodeficiency-centromeric instability,facial anomalies syndrome (ICF); Rubinstein,Taybi syndrome (RSTS); and Coffin,Lowry syndrome (CLS). [source]


    Perinatal development of the rat kidney: Apoptosis and epidermal growth factor

    CONGENITAL ANOMALIES, Issue 3 2003
    Toshiya Okada
    ABSTRACT, Localization of apoptotic cells in the kidney of perinatal rats was examined by the terminal deoxynucleotidyl transferase,mediated d,UTP,biotin nick end labeling (TUNEL) method and electron microscopy. Perinatal changes in the percentage of kidney cells with DNA fragmentation were determined by flow cytometric analysis. Through observation of two successive sections, the relationship between the localization of the epidermal growth factor receptor (EGFR) positive cells and TUNEL positive cells in the kidney was determined. From fetal day 18 to neonatal day 5, TUNEL positive cells were noted in immature glomeruli, collecting ducts and interstitium. Electron microscopically, chromatin condensed nuclei and apoptotic bodies were seen in the same tissue component as the TUNEL positive cells. The percentage of DNA fragmented cells significantly increased from fetal days 18 to 20 and significantly decreased from fetal days 20 to 22, while they still remained low in the neonatal period. The TUNEL positive cells in immature glomeruli and collecting ducts were not reactive to the EGFR antibody. The TUNEL positive cells were not observed in the proximal tubular cells, which were positive to EGFR antibody. These results indicate that apoptotic cells are present in the kidney throughout the perinatal period in the rat and that EGF plays an important role in perinatal development of the rat kidney. [source]


    O-10 Endometrial cells in cervical smears: cytological features associated with clinically significant endometrial pathology

    CYTOPATHOLOGY, Issue 2007
    R. N. Tiam
    Introduction:, To establish the significance of cytological features which could predict clinically significant endometrial pathology, and therefore guide reporting practice in cervical samples. Methods:, A retrospective review of SurePath liquid-based cytology (LBC) cervical samples between 2002 and 2006, obtained at screening and colposcopy. These smears contained normal endometrial cells present at inappropriate times of the menstrual cycle, endometrial cells with atypia (borderline change) and with features suspicious / diagnostic of endometrial carcinoma (glandular neoplasia). False negative and false positive cases detected on subsequent histology were also included. The control group comprised negative samples and a few abnormal smears. All smears were randomly assigned and blinded to menopausal status, age, use of oral contraceptive pill and hormone replacement therapy and presence of intrauterine device. Each smear was reviewed for 16 cytologic criteria and a cytological diagnosis was given for each. Results:, A total of 219 smears were available for review; 137 were negative, out of which 85 contained normal endometrial cells, 41 contained endometrial cells with atypia, 10 contained endometrial cells with features suggestive of adenocarcinoma and 31 contained endometrial cells with features diagnostic of adenocarcinoma. The feature most associated with benign endometrial cells is top hat with central cell condensation. In contrast, the features associated with malignant endometrial cells are smooth nuclear membrane, pale chromatin, small nucleoli and scalloped borders. Discussion:, The criteria identified in this study do not definitively define a neoplastic process, but appear to be helpful in individual cases. This study emphasises that endometrial changes should be always interpreted with the relevant clinical information, which would otherwise lead to overdiagnosis in premenopausal women. [source]


    TOGp regulates microtubule assembly and density during mitosis and contributes to chromosome directional instability

    CYTOSKELETON, Issue 8 2009
    Lynne Cassimeris
    Abstract TOGp, a member of the XMAP215 MAP family, is required for bipolar mitotic spindle assembly. To understand how TOGp contributes to spindle assembly, we examined microtubule dynamics after depleting TOGp by siRNA. Fluorescence recovery after photobleaching of GFP-tubulin demonstrated that spindle microtubule turnover is slowed two-fold in the absence of TOGp. Consistent with photobleaching results, microtubule regrowth after washout of the microtubule depolymerizing drug nocodazole was slower at the centrosomes and in the vicinity of mitotic chromatin in cells depleted of TOGp. The slower microtubule turnover is likely due to either nucleation or the transitions of dynamic instability because TOGp depletion did not effect the rate of plus end growth, measured by tracking EB1-GFP at microtubule ends. In contrast, microtubule regrowth after nocodazole washout was unaffected by prior depletion of TACC3, a centrosomal protein that interacts with TOGp. Kinetochore fibers in both untreated and TOGp-depleted cells were stable to incubation at 4°C or lysis in buffer containing calcium indicating that stable kinetochore-microtubule attachments are formed in the absence of TOGp. Depletion of TOGp, but not TACC3, reduced kinetochore oscillations during prometaphase/metaphase. Defects in oscillations are not due simply to multipolarity or loss of centrosome focus in the TOGp-depleted cells, since kinetochore oscillations appear normal in cells treated with the proteosome inhibitor MG132, which also results in multipolar spindles and centrosome fragmentation. We hypothesize that TOGp is required for chromosome motility as a downstream consequence of reduced microtubule dynamics and/or density. Cell Motil. Cytoskeleton 2009. © 2009 Wiley-Liss, Inc. [source]


    Myosin Va phosphorylated on Ser1650 is found in nuclear speckles and redistributes to nucleoli upon inhibition of transcription

    CYTOSKELETON, Issue 6 2008
    Maria Cristina S. Pranchevicius
    Abstract Nuclear actin and nuclear myosins have been implicated in the regulation of gene expression in vertebrate cells. Myosin V is a class of actin-based motor proteins involved in cytoplasmic vesicle transport and anchorage, spindle-pole alignment and mRNA translocation. In this study, myosin-Va, phosphorylated on a conserved serine in the tail domain (phospho-ser1650 MVa), was localized to subnuclear compartments. A monoclonal antibody, 9E6, raised against a peptide corresponding to phosphoserine1650 and flanking regions of the murine myosin Va sequence, was immunoreactive to myosin Va heavy chain in cellular and nuclear extracts of HeLa cells, PC12 cells and B16-F10 melanocytes. Immunofluorescence microscopy with this antibody revealed discrete irregular spots within the nucleoplasm that colocalized with SC35, a splicing factor that earmarks nuclear speckles. Phospho-ser1650 MVa was not detected in other nuclear compartments, such as condensed chromatin, Cajal bodies, gems and perinucleolar caps. Although nucleoli also were not labeled by 9E6 under normal conditions, inhibition of transcription in HeLa cells by actinomycin D caused the redistribution of phospho-ser1650 MVa to nucleoli, as well as separating a fraction of phospho-ser1650 MVa from SC35 into near-neighboring particles. These observations indicate a novel role for myosin Va in nuclear compartmentalization and offer a new lead towards the understanding of actomyosin-based gene regulation. Cell Motil. Cytoskeleton 2008. © 2008 Wiley-Liss, Inc. [source]


    Erasure of the paternal transcription program during spermiogenesis: The first step in the reprogramming of sperm chromatin for zygotic development

    DEVELOPMENTAL DYNAMICS, Issue 8 2008
    Junke Zheng
    No abstract is available for this article. [source]


    Erasure of the paternal transcription program during spermiogenesis: The first step in the reprogramming of sperm chromatin for zygotic development

    DEVELOPMENTAL DYNAMICS, Issue 5 2008
    Junke Zheng
    Abstract Male germ cells possess a unique epigenetic program and express a male-specific transcription profile. However, when its chromatin is passed onto the zygote, it expresses an transcription/epigenetic program characteristic of the zygote. The mechanism underlying this reprogramming process is not understood at present. In this study, we show that an extensive range of chromatin factors (CFs), including essential transcription factors and regulators, remodeling factors, histone deacetylases, heterochromatin-binding proteins, and topoisomerases, were removed from chromatin during spermiogenesis. This process will erase the paternal epigenetic program to generate a relatively naive chromatin, which is likely to be essential for installation of the zygotic developmental program after fertilization. We have also showed that transcription termination in male germ cells was temporally correlated with CF dissociation. A genome-wide CF dissociation will inevitably disassemble the transcription apparatus and regulatory mechanism and lead to transcription silence. Based on data presented in this and previous studies (Sun et al., Cell Research [2007] 17:117,134), we propose that paternal-zygotic transcription reprogramming begins with a genome-wide CF dissociation to erase the existing transcription program in later stages of spermatogenesis. This will be followed by assembling of the zygotic equivalent after fertilization. The transcription/epigenetic program of the male germ cell is transformed into a zygotic one using an erase-and-rebuild strategy similar to that used in the maternal-zygotic transition. It is also noted that transcription is terminated long after meiosis is completed and before chromatin becomes highly condensed during spermatogenesis. The temporal order of these events suggests that transcription silence does not have to be coupled to meiosis or chromatin condensation. Developmental Dynamics 237:1463-1476, 2008. © 2008 Wiley-Liss, Inc. [source]


    Role of histone and transcription factor acetylation in diabetes pathogenesis

    DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 5 2005
    Steven G. Gray
    Abstract Globally, diabetes (and, in particular, type 2 diabetes) represents a major challenge to world health. Currently in the United States, the costs of treating diabetes and its associated complications exceed $100 billion annually, and this figure is expected to soar in the near future. Despite decades of intense research efforts, the genetic basis of the events involved in the pathogenesis of diabetes is still poorly understood. Diabetes is a complex multigenic syndrome primarily due to beta-cell dysfunction associated with a variable degree of insulin resistance. Recent advances have led to exciting new developments with regard to our understanding of the mechanisms that regulate insulin transcription. These include data that implicate chromatin as a critical regulator of this event. The ,Histone Code' is a widely accepted hypothesis, whereby sequential modifications to the histones in chromatin lead to regulated transcription of genes. One of the modifications used in the histone code is acetylation. This is probably the best characterized modification of histones, which is carried out under the control of histone acetyltransferases (HATs) and histone deacetylases (HDACs). These enzymes also regulate the activity of a number of transcription factors through acetylation. Increasing evidence links possible dysregulation of these mechanisms in the pathogenesis of diabetes, with important therapeutic implications. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    Differential diagnostic features of small cell carcinoma in the uterine cervix

    DIAGNOSTIC CYTOPATHOLOGY, Issue 9 2008
    Min Jung Kim M.D.
    Abstract Small cell carcinoma (SMCC) of the uterine cervix is rare and known to be an aggressive tumor, but there are only few reports on the cytologic features of cervical SMCC. This rare small cell lesion should be distinguished from malignant lymphoma (ML), squamous cell carcinoma in situ (SCIS), and chronic lymphocytic cervicitis (CLC). By clarifying cytologic features and reevaluating the significance of cervical cytologic smears to reveal these cervical lesions, we can improve the diagnostic specificity and patient's outcome. The clinical record and available cervical smears from 13 cases of SMCC, four cases of malignant lymphoma, 20 cases of SCIS, and five cases of CLC were analyzed. The cytologic differential diagnostic points of SMCC were nuclear molding and smearing (100%), salt and pepper chromatin (100%), exudative and necrotic background (91.7%), various architectures including individual cells (83.3%), tight clusters (75%) and feathering and strip (50%), and inconspicuous nucleoli (75%). Early diagnosis of the cervical SMCC by cytology and treatment is important for better outcome of patients. Diagn. Cytopathol. 2008;36:618,623. © 2008 Wiley-Liss, Inc. [source]


    Fine-needle aspiration of metastatic prostatic neuroendocrine carcinomas: Cytomorphologic and immunophenotypic features

    DIAGNOSTIC CYTOPATHOLOGY, Issue 8 2008
    Guoping Cai M.D.
    Abstract Metastatic prostatic carcinoma may, in rare occasions, present as a neuroendocrine tumor. Its recognition is crucial to avert a wrongful exclusion of prostate as a primary site. We report five cases of metastatic prostatic neuroendocrine carcinoma diagnosed by image-guided fine-needle aspiration biopsy. The aspirate smears showed loosely cohesive or dyscohesive clusters of tumor cells with scanty (three cases) to moderate amount (two cases) of cytoplasm, speckled or coarse chromatin and inconspicuous nucleoli. Nuclear molding and necrosis were focally present in two cases. Immunohistochemically, the tumor cells were positive for synaptophysin or/and chromogranin, but negative for prostatic specific antigen and prostatic specific acid phosphatase. Review of prior prostate biopsies/resections revealed adenocarcinoma with focal neuroendocrine differentiation in all cases, with two cases being newly recognized on retrospective review. Confirming neuroendocrine differentiation in the prior biopsy/resection may help to establish a link between metastasis and prostate primary. Diagn. Cytopathol. 2008; 36: 545,549. © 2008 Wiley-Liss, Inc. [source]


    Cytomorphology of lymphoepithelioma-like carcinoma of the urinary bladder: Report of two cases

    DIAGNOSTIC CYTOPATHOLOGY, Issue 8 2008
    Guoping Cai M.D.
    Abstract Lymphoepithelioma-like carcinoma (LELC) of the urinary bladder is a rare variant of high-grade urothelial carcinoma. Here, we report urine cytologic findings in two cases of this rare entity, the diagnosis of which was confirmed by histopathological examination of the resected tumors. The cytomorphologic features included large tumor cells with high nuclear to cytoplasmic ratios, vesicular chromatin, and prominent nucleoli, presented as single cells or intermixed with inflammatory cells. The differential diagnosis included otherwise typical high-grade urothelial carcinoma, reactive urothelial cells and rarely large cell lymphoma. The rarity of the tumor cells may impose a diagnostic challenge in urine specimen. Diagn. Cytopathol. 2008; 36: 600,603. © 2008 Wiley-Liss, Inc. [source]


    Fine-needle aspiration cytology of Rosai-Dorfman disease of bone

    DIAGNOSTIC CYTOPATHOLOGY, Issue 7 2008
    Xin Jing M.D.
    Abstract Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a rare, benign self-limiting condition of unknown etiology. Less than a quarter of cases have only extranodal involvement and a few cases of skeletal involvement of Rosai-Dorfman disease without associated lymphadenopathy have been reported in the literature. We herein report cytohistologic findings in a case of sole skeletal Rosai-Dorfman disease in a 51-year-old woman who presented with an expansile, heterogeneous lesion at T11 with cord compression and edema. A CT-guided fine-needle aspiration of T-11 lesion was performed and the sample was processed by ThinPrep technique. The ThinPrep smear showed characteristic features of Rosai-Dorfman disease including hypercellularity with moderate number of histiocytes in a background of lymphocytes, plasma cells, and neutrophils. The histiocytes possessed abundant, pale and vacuolated cytoplasm, rounded nuclei with smooth nuclear membranes, fine chromatin, and distinct nucleoli. The histiocytes showed emperipolesis of lymphocytes and neutrophils. The diagnosis was confirmed by concurrent biopsy with immunhistochemical study. Our case highlighted the role of fine-needle aspiration with ThinPrep technique in the diagnosis of Rosai-Dorfman disease. Diagn. Cytopathol. 2008;36:516,518. © 2008 Wiley-Liss, Inc. [source]


    Pancreatic mucinous lesions: A retrospective analysis with cytohistological correlation

    DIAGNOSTIC CYTOPATHOLOGY, Issue 11 2006
    Jing Zhai M.D., Ph.D.
    Abstract The diagnosis of mucinous pancreatic lesions, which include mucinous noncystic adenocarcinoma, intraductal papillary mucinous neoplasm (IPMN), mucinous cystic neoplasm (MCN), and mucinous metaplasia, is critical, given different clinical management and prognosis. This retrospective study is done to assess the cytological features and pitfalls associated with these entities in cytological samples. A search for pancreatic cytology specimens with histological confirmation of the various pancreatic mucinous lesions was done from 1988 to 2005: 9 mucinous adenocarcinoma, 14 IPMN, 11 MCN, and 3 mucinous metaplasia. The majority (35/37) had been endoscopic ultrasound-guided fine-needle aspirations. The cellularity, background extracellular mucin, epithelial architecture, mucinous nature of the epithelium, cell shape, and nuclear features were evaluated on the cytology material. Of the 22 cytological features evaluated, the presence of three-dimensional clusters, micropapillary structures, and nuclear atypia, which includes nuclear crowding, increased N/C ratio, anisonucleosis, nuclear membrane contour irregularity, clumpy chromatin, and prominent nucleoli, was found to be consistently associated with mucinous adenocarcinoma. There were no statistically significant cytological features, which helped in differentiating IPMN, MCN, and mucinous metaplasia. There was a relatively high false-positive rate in the IPMN group (5/14, 36%). Review of the histological specimen showed severe dysplastic epithelial change in these cases. One false-positive case of mucinous metaplasia (1/3, 33%) showed marked intraepithelial acute inflammation. The cytological diagnosis of mucinous pancreatic lesions remains challenging, except for mucinous noncystic adenocarcinoma. The findings were largely nonspecific in the differentiation between IPMN, MCN, mucinous metaplasia, and incidentally sampled gastrointestinal epithelium. False-positive diagnosis of adenocarcinoma occurs not infrequently in the setting of IPMN with severe dysplastic epithelial change and in lesions with associated acute inflammation, and can be a pitfall in the diagnosis of these lesions. Diagn. Cytopathol. 2006;34: 724,730. © 2006 Wiley-Liss, Inc. [source]


    Uterine adenosarcoma detected by Papanicolaou smear: A Case report,

    DIAGNOSTIC CYTOPATHOLOGY, Issue 7 2006
    F.R.C.P.C., Sylvia Pasternak M.D.
    Abstract Adenosarcoma is a rare uterine biphasic tumor composed of benign epithelial elements and a sarcomatous stroma. Although it is well described histologically, its cytological features are rarely mentioned in the literature. We describe a case of uterine adenosarcoma that was first detected by Papanicolau (Pap) smear. Numerous crowded clusters of spindle cells were present within a bloody background, as well as a few smaller, dyscohesive groups with cells showing high N:C ratio and oval to round nuclei with coarse chromatin and small nucleoli. A few nuclear grooves were identified. Adenosarcomas are rare lesions but should be considered in the differential diagnosis when spindled cells are noted in a pap smear. Diagn. Cytopathol. 2006;34:495,498. © 2006 Wiley-Liss, Inc. [source]


    Primary relapse of acute lymphoblastic leukemia in a cervical smear: A case report

    DIAGNOSTIC CYTOPATHOLOGY, Issue 7 2006
    Akiko Ikuta M.D.
    Abstract Uterine cervix and corpus are rarely the initial site of relapse in leukemia or lymphoma. We report herein a case of uterine cervical relapse with B-cell acute lymphoblastic leukemia (ALL). The patient, a 60-yr-old woman, had a history of ALL that had been in remission for 2 yr after chemotherapy. She presented with a chief complaint of genital bleeding. In a routine cervico-vaginal Papanicolau smear, abundant atypical lymphoid cells with round-to-oval nuclei, scant cytoplasm, and high nuclear to cytoplasmic ratios was observed. The nuclei of these cells had fine and dark chromatin and thickened nuclear membranes, with one or several nucleoli being visible. Biopsy under colposcope was performed, and a diagnosis of relapse of ALL was confirmed. The ongoing genital bleeding presented a problem with clinical management of the patient. It was decided to proceed with hysterectomy to end that problem and thereafter proceed with therapy directed against the leukemia. Our results suggest that in patients with known extrauterine cancer, the presence of malignancy in uterine cellular samples provides information regarding the extent of the neoplasm. Diagn. Cytopathol. 2006;34:499,502. © 2006 Wiley-Liss, Inc. [source]


    Metastatic mammary carcinomas with endocrine features: Potential diagnostic pitfalls

    DIAGNOSTIC CYTOPATHOLOGY, Issue 1 2005
    Anjali Saqi M.D.
    Abstract Mammary carcinomas with endocrine differentiation (MCED) are an uncommon subtype of breast carcinomas that are morphologically indistinguishable from low-grade endocrine neoplasms arising in other organs. Aspirates of MCED yield relatively monotonous cells with eccentrically placed nuclei containing characteristic "salt and pepper" chromatin. In the breast, these features represent MCED. In extramammary sites, the differential is more extensive, and diagnosing MCED metastates to the lung, a common location for primary and metastatic endocrine tumors, can be a challenging task, with significant clinical implications. Although primary MCED have been described extensively in the cytology literature, secondary pulmonary MCED have not been reported to the best of our knowledge. We report three cases of MCED metastatic to the lung and present the cytological and immunohistochemical features. Diagn. Cytopathol. 2005;33:49,53. © 2005 Wiley-Liss, Inc. [source]


    Desmoplastic round cell tumor of childhood: Can cytology with immunocytochemistry serve as an alternative for tissue diagnosis?

    DIAGNOSTIC CYTOPATHOLOGY, Issue 6 2005
    Dr Brijal Dave M.D.
    Abstract There are limited reports on the cytology of desmoplastic small round cell tumors (DSRCT). Fine needle aspiration biopsy (FNAB) findings in seven aspirates from four cases of histologically and immunohistochemically confirmed cases were analyzed with the main intention of ascertaining if cytological diagnosis of DSRCT is possible. Also assessed were the immunocytochemistry(ICC) findings in these cases. The basic cytological impression was that of a cohesive small round cell tumor. Nuclei showed granular chromatin with grooves, nuclear molding and inconspicuous nucleoli. Stromal fragments were noted in all four cases. In two cases, awareness of cytological features in the appropriate clinical context led to a suggestion of the diagnosis of DSRCT on cytology itself. ICC on destained smears showed positivity for cytokeratin, epithelial membrane antigen (EMA), desmin and WT-1 in two cases. In conclusion, given the right clinical setting, a cytological diagnosis of DSRCT is plausible and in conjunction with ICC may help in documenting the polyphenotypic nature and thereby confirming the diagnosis. Diagn. Cytopathol. 2005;32:330,335. © 2005 Wiley-Liss, Inc. [source]


    Fine-needle aspiration cytology of pleomorphic hyalinized angiectatic tumor: A case report

    DIAGNOSTIC CYTOPATHOLOGY, Issue 4 2005
    Oscar Lin M.D., Ph.D.
    Abstract Pleomorphic hyalinized angiectatic tumor (PHAT) of soft parts is a neoplasm characterized by spindle and pleomorphic cells associated with an angiectatic vasculature. We describe the cytological findings of a fine-needle aspiration biopsy (FNAB) from the right medial knee of a 45-yr-old woman. The aspirate material was entirely submitted in Cytolit solution. The specimen was moderately cellular and was comprised of spindle cells in a background of fibrinous material. The cells varied from small, bland spindle cells with a fine chromatin pattern and inconspicuous nucleoli to larger pleomorphic cells with coarser chromatin and occasional intranuclear inclusions. Most of the cells were arranged singly with sporadic small cluster formation with indistinct cell borders. Rare mononuclear inflammatory cells morphologically compatible with mast cells were identified. The differential diagnosis include solitary fibrous tumor (SFT) and ancient schwannoma, which also shows fibrous-like material and spindle cells that may have intranuclear inclusions. Diagn. Cytopathol. 2005;32:238,242. © 2005 Wiley-Liss, Inc. [source]


    Low-grade urothelial carcinoma: Reappraisal of the cytologic criteria on ThinPrep®

    DIAGNOSTIC CYTOPATHOLOGY, Issue 3 2003
    Ph.D., Wei Xin M.D.
    Abstract The diagnostic criteria for low-grade urothelial lesions that have been described in the past were based on urinary specimens prepared by the cytospin method. Recognizing the recent popularity of the ThinPrep® methodology and the cytologic alterations it introduces to the cellular features, we sought to evaluate the reproducibility of these criteria in ThinPrep urinary samples. One hundred twenty-six ThinPrep urinary specimens with a tissue diagnosis of low-grade urothelial carcinoma (LGUC) and 45 negative controls were evaluated. Three pathologists blindly reviewed the slides separately and the consensus on each feature was used in the study. Logistic regression analysis was used to determine which criteria in combination were most predictive of low-grade urothelial carcinoma. All specimens were evaluated for the following 18 features: nucleus/cytoplasm ratio, irregular nuclear border, cytoplasm homogeneity, cell clusters, high cellularity, prominent nucleoli, granular nuclear chromatin, hyperchromasia, acute inflammation, vesicular chromatin, nuclear molding, nuclear eccentricity, elongated nuclei, necrosis, anisonucleosis, irregular bordered fragments, absent cytoplasmic collar, and peripheral palisading. High nucleus-to-cytoplasm ratio, irregular nuclear borders, and homogeneous cytoplasm (combination sensitivity of 59% and specificity of 100%) were the best predictive features for LGUC. Minor predictive criteria were eccentric nuclei and nuclear molding. ThinPrep provides well preserved, cleaner specimens without significantly altering the morphology. The three key criteria applied in cytospin specimens to diagnose LGUC were reproducible in ThinPrep specimens. Diagn. Cytopathol. 2003;29:125,129. © 2003 Wiley-Liss, Inc. [source]


    Diagnosis of melanoma aspirates on ThinPrep®: The University of Michigan experience

    DIAGNOSTIC CYTOPATHOLOGY, Issue 5 2002
    Güliz Akdas Barkan M.D.
    Abstract The purpose of this study was to compare the cytologic features of melanoma fine-needle aspirates (FNAs) prepared by ThinPrep® (TP) with those in conventional smears (CS) and to identify any diagnostic pitfalls. Fifty-one aspirates diagnosed as melanoma were obtained, 36 of which were prepared by both TP and CS. The preparations were evaluated for cellularity, cell aggregates, cellular appearance, melanin pigment, cytoplasmic, and nuclear features. Categorical data were analyzed by the chi-square test and continuous data by the Wilcoxin-signed rank test. Correlation was determined by Spearman's test for bivariate correlations (rho). Good correlation between the two methods was identified for the following features: cellularity, cell type, bi/multinucleated cells, cytoplasmic features, NC ratio, and presence of macronucleoli. TP exhibits coarser chromatin compared to CS (P = 0.005). Six of 36 CS contained large cellular groups; none of the TP contained them (P = 0.018). Twenty-five of 36 CS contained intranuclear inclusions as opposed to 12/36 TP (P < 0.001). The number of inclusions was significantly reduced on TP. The amount of intracellular melanin was the same with both techniques. Background melanin was markedly reduced on TP except when either trapped by fibrin or attached to cellular clusters (P = 0.006). Background blood was also markedly reduced on TP (P < 0.005). In summary, the cytological features of TP and CS for FNA evaluation of melanoma correlate well; however, one needs to be aware of the cytologic alterations introduced by TP. TP is a sufficient preparation method in the diagnosis of melanoma FNA aspirates when performed by clinicians. It is also a useful adjunct in bloody or low-cellular aspirates, where it tends to reduce the background blood and concentrate the cells. Diagn. Cytopathol. 2002;26:334,339. © 2002 Wiley-Liss, Inc. [source]


    Morphologic predictors of papillary carcinoma on fine-needle aspiration of thyroid with ThinPrep® preparations

    DIAGNOSTIC CYTOPATHOLOGY, Issue 6 2001
    Yilin Zhang M.D.
    Abstract Although the cytologic features of papillary carcinoma of the thyroid are well-known, none is entirely specific. We conducted this study to determine the minimal criteria necessary to achieve 100% specificity for the diagnosis of papillary carcinoma on fine-needle aspiration (FNA). Forty patients with histologically confirmed papillary carcinoma and 17 patients with other thyroid lesions who underwent preoperative FNA at Beth Israel Deaconess Medical Center during a 4-yr period were included in the study. All cytology slides were prepared with the ThinPrep® processing technique. Various architectural and nuclear features were evaluated, with a score assigned to each feature, and correlated with the histologic diagnosis of papillary carcinoma. Intranuclear inclusions, papillary and/or sheet arrangements, nuclear grooves, powdery chromatin, nuclear molding, high cellularity, and small nucleoli were significantly associated with papillary carcinoma (P < 0.05). The requirement of any intranuclear inclusions and many nuclear grooves, or a minimum of sum of scores (of the above eight features) of 10, yields 100% specificity and approximately 70% sensitivity. Cases with fewer features can be reported as suspicious or indeterminate for papillary carcinoma. A quantitative/probabilistic approach in the reporting of thyroid FNA provides a practical guide for management of patients with thyroid nodules. Diagn. Cytopathol. 24:378,383, 2001. © 2001 Wiley-Liss, Inc. [source]


    Structure and ultrastructure of the spermatozoa of Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman and Platner (Hymenoptera: Trichogrammatidae)

    ACTA ZOOLOGICA, Issue 3 2000
    José Lino-Neto
    Abstract Lino-Neto, J., Báo, S. N. and Dolder, H. 2000. Structure and Ultrastructure of the Spermatozoa of Trichogramma pretiosum Riley and Trichogramma atopovirilia Oatman and Platner (Hymenoptera: Trichogrammatidae). ,Acta Zoologica (Stockholm) 81: 205,211 Spermatozoa of the Trichogramma pretiosum and T. atopovirilia are very slender and long, about 0.35 µm in diameter and 283 µm and 106 µm in length, respectively. Under light microscopy, they appear wavy along their entire length. The head contains a small acrosome which, together with the initial nuclear region is surrounded by an ,extracellular sheath', from which innumerable filaments irradiate. The nucleus is filled with homogeneous, compact chromatin and is attached to the flagellum by an electron dense centriolar adjunct, which extends anteriorly from the nuclear base. The flagellum consists of an axoneme with the 9 + 9 + 2 microtubule arrangement pitched in a long helix, as well as a pair of spiralling mitochondrial derivatives which coil around the axoneme. Based on these characteristics, the sperm of these Trichogramma are very similar to the chalcidoids studied to date and differ from non-chalcidoid Hymenoptera. They differ widely from the sperm of T. dendrolimi and T. ostriniae studied, where no helically twisted structure is shown. However, based on these results we argue that the spiralling of the flagellar structures is a synapomorphy for Trichogrammatidae as well as for Eulophidae + Eurytomidae + Pteromalidae. [source]


    Micronuclei and chromatid buds are the result of related genotoxic events

    ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 1 2001
    Luis Serrano-García
    Abstract Chromatin buds (CHB), broken eggs, or budding cell nuclei are structures similar to micronuclei (MN) in shape, structure, and size, which are linked to the main nuclei of cells by a thread or stalks of chromatin. They have been observed in numerous cell types and there are reports of their existence relating them with MN or with genotoxic events. However, there is no systematic study reporting their frequency and no experiment has been done to ascertain whether they are really induced by genotoxins. Furthermore, they have been discarded as genotoxic events with the argument that they are not formed in dividing cells. Studies are presented here that indicate that CHB can be considered as genotoxic events and that their origin is comparable to that of MN. Bromodeoxyuridine (BrdU) was used to label proliferating lymphocytes, which were later identified by means of an immunohistochemical method, using the H2O2,DAB stain. The results show that CHB are consistently formed where MN are seen. CHB were induced by the clastogen mitomycin C (MMC) as well as by the aneuploidogen colcemid, with frequencies similar to MN in both cases, and to multinucleated cells in the case of colcemid. CHB occur in lymphocytes of smokers with frequencies similar to those of MN, and we found that the infection with Taenia solium metacestodes induced a comparable increase of both MN and CHB frequency in lymphocytes from pigs. Environ. Mol. Mutagen. 38:38,45, 2001 © 2001 Wiley-Liss, Inc. [source]


    Single layer centrifugation of stallion spermatozoa consistently selects the most robust spermatozoa from the rest of the ejaculate in a large sample size

    EQUINE VETERINARY JOURNAL, Issue 7 2010
    J. M. MORRELL
    Summary Reasons for performing study: An improvement in sperm quality after single layer centrifugation (SLC) has been seen in previous studies using small sample sizes (for example, n = 10 stallions). There is a need to investigate whether this improvement is repeatable over several breeding seasons with a larger number of stallions (n , 30 stallions). Objective: To make a retrospective analysis of the results of SLC performed on more than 250 sperm samples (176 ejaculates) from 31 stallions in 3 consecutive breeding seasons. Methods: Sperm quality (motility, proportion of morphologically normal spermatozoa and the proportion of spermatozoa with undamaged chromatin) was assessed before and after SLC. Results: All parameters of sperm quality examined were significantly better in sperm samples after SLC than in their unselected counterparts (P<0.001 for each parameter). The yield of spermatozoa obtained after SLC was influenced by the type of extender used and also by the concentration of spermatozoa in the original ejaculate, with fewer spermatozoa being recovered when the loading dose contained a high concentration of spermatozoa. The optimal concentration was approximately 100 × 106/ml. Sperm concentration in the samples loaded on to the colloid influenced the sperm yield while the type of semen extender affected sperm quality and survival. Furthermore, the scaled-up SLC method was found to be suitable for use with a range of ejaculates, with similar sperm kinematics being observed for standard and scaled-up preparations. Conclusions: SLC consistently improved the quality of stallion sperm samples from a large number of ejaculates. The method could be scaled-up, allowing larger volumes of ejaculate to be processed easily from a wide range of stallions. [source]


    Impaired CD4+ T-cell proliferation and effector function correlates with repressive histone methylation events in a mouse model of severe sepsis

    EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2010
    William F. Carson
    Abstract Immunosuppression following severe sepsis remains a significant human health concern, as long-term morbidity and mortality rates of patients who have recovered from life-threatening septic shock remain poor. Mouse models of severe sepsis indicate this immunosuppression may be partly due to alterations in myeloid cell function; however, the effect of severe sepsis on subsequent CD4+ T-cell responses remains unclear. In the present study, CD4+ T cells from mice subjected to an experimental model of severe sepsis (cecal ligation and puncture (CLP)) were analyzed in vitro. CD4+CD62L+ T cells from CLP mice exhibited reduced proliferative capacity and altered gene expression. Additionally, CD4+CD62L+ T cells from CLP mice exhibit dysregulated cytokine production after in vitro skewing with exogenous cytokines, indicating a decreased capability of these cells to commit to either the TH1 or TH2 lineage. Repressive histone methylation marks were also evident at promoter regions for the TH1 cytokine IFN-, and the TH2 transcription factor GATA-3 in naïve CD4+ T cells from CLP mice. These results provide evidence that CD4+ T-cell subsets from post-septic mice exhibit defects in activation and effector function, possibly due to chromatin remodeling proximal to genes involved in cytokine production or gene transcription. [source]