Chromatin Nucleoli Research Articles

Spontaneous progression of cutaneous angiomatosis to an infiltrative sarcoma-like tumour in a bull

CASE HISTORY: A 5-month-old valuable Red Holstein bull presented with a cutaneous mass on the fetlock of the right hind limb. The mass was removed and histologically diagnosed as a benign angiomatosis. Four months later, the mass reoccurred on the same leg.PATHOLOGICAL FINDINGS: The first excision biopsy consisted of numerous blood vessels of different diameters and wall thicknesses. Often, the smaller vessels were oriented around a larger, vein-like vessel. The endothelial cells were elongated with small oval to elongated nuclei with dense chromatin. Following recurrence, the mass showed clear signs of infiltrative growth, including solid bundles of cells, increased polymorphism and round to oval nuclei with coarse chromatin and distinctive nucleoli. The neoplastic cells were immunohistochemically positive for von Willebrand Factor (vWF).DIAGNOSIS: Angiomatosis with focal progression to an infiltrative growing sarcoma-like tumour.CLINICAL RELEVANCE: This case represents the progression of a benign vascular proliferation, often considered as a reactive process, into a more aggressively behaving neoplasm. The clinical behaviour and histopathological morphology were strikingly similar to previous cases described in human and veterinary medicine.

DIETARY SUPPLEMENTATION OF VITAMIN C, L-ASCORBATE 2-TRIPHOSPHATE CALCIUM (LATP-Ca) ON OOCYTE DEVELOPMENT OF MAJOR CARP ROHU (LABEO ROHITA) REARED IN A NATURAL CONCRETE POND

The aim of this study was to evaluate the effect of vitamin C L-ascorbate 2-triphosphate (LATP-Ca)on Indian major carp rohu (Labeo rohita) (Hamilton) during intensive aquaculture. Rohu were fedwith vitamin C (LATP-Ca) supplementation at doses of D1 (control) and D2 (500 mg/kg) diet for 10weeks. The effects were assessed by comparing the treated groups of fish to that of control group.Vitamin C (LATP-Ca) supplementation exerted significant (P<0.05) effects on oocyte developmentof rohu (Labeo rohita). A number of distinct developmental stages of oocyte can be delineated andoocyte growth in major carp rohu (Labeo rohita) found in two distinct phases; primary growthphase (PGP) and the secondary growth phase (SGP). In PGP, oogonia, chromatin nucleolus, earlyand peri nucleolus stage oocyte with Balbiani’s vitelline body were observed while two types ofinclusions, lipid and protein, respectively were formed during vitellogenesis in the SGP. SGPdevelopment was found for a short period of time as compared to PGP. Similarly, development ofoocyte was very poor in fish fed with controlled diet.DOI: http://dx.doi.org/10.3126/eco.v19i0.9849EcoprintAn International Journal of EcologyVol. 19, 2012Page: 7-15Uploaded date: 2/14/2014

Neuroendocrine tumor of gallbladder: a case report in maharaj nakorn chiang mai hospital

Introduction Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) originate from neuroendocrine cells which distribute along the entire gastrointestinal tract and pancreas. The site of predilection is the stomach and the tumors are mostly graded as G1 NETs; however, gallbladder NETs are extremely rare, showing only 0.5% of all NETs with unfavorable prognosis. Case presentation A 68-year-old woman underwent open cholecystectomy for symptomatic gallstones, and the gallbladder was diagnosed as poorly differentiated adenocarcinoma. Two months later, two liver metastases were detected in segment 4a and 5. Hepatic segmentectomy (segment 4a and 5) was done. The liver pathology revealed infiltration of small round tumor cells containing small nuclei with fine granular chromatin and inconspicuous nucleoli. The tumor cells were immunoreactive for chromogranin A; therefore, metastatic small cell carcinoma was diagnosed. The gallbladder lesion was reviewed and the diagnosis was revised to neuroendocrine carcinoma grade 3. The patient was sent to the provincial hospital for further chemotherapeutic treatment. Conclusion Neuroendocrine tumors of gallbladder are uncommon and indistinguishable from carcinoma of gallbladder clinically and surgically. Features from radiographic investigation and histopathological features are essential for making the diagnosis. Moreover, the prognosis of gallbladder neuroendocrine tumor is poor and the 5-year survival rate is worse than neuroendocrine tumor from other locations.

ESET methylates UBF at K232/254 and regulates nucleolar heterochromatin plasticity and rDNA transcription

The remodeling of chromatin in the nucleolus is important for the control of ribosomal DNA (rDNA) transcription and ribosome biogenesis. Herein, we found that upstream binding factor (UBF) interacts with ESET, a histone H3K9 methyltransferase and is trimethylated at Lys (K) 232/254 by ESET. UBF trimethylation leads to nucleolar chromatin condensation and decreased rDNA transcriptional activity. UBF mutations at K232/254A and K232/254R restored rDNA transcriptional activity in response to ESET. Both ESET-ΔSET mutant and knockdown of ESET by short hairpin RNA reduced trimethylation of UBF and resulted in the restoration of rDNA transcription. Atomic force microscopy confirmed that UBF trimethylated by ESET modulates the plasticity of nucleolar chromatin. We further demonstrated that UBF trimethylation at K232/254 by ESET deregulates rDNA transcription in a cell model of Huntington’s disease. Together, our findings show that a novel epigenetic modification of UBF is linked to impaired rDNA transcription and nucleolar chromatin remodeling, which may play key roles in the pathogenesis of neurodegeneration.

"Hurthle Cell Lesion": A Clinicopathologic Study and Significance of Cytological Diagnosis

Introduction: Since the 2008 publication of the Bethesda terminology for thyroid cytopathology, diagnosis rates of atypia of undetermined significance (AUS) from 2.1% to >10% have been reported. Although a majority with benign follow-up prove to be adenomatous nodules, some show lymphocytic thyroiditis (known to be associated with cytologic atypia) on follow up. We sought to examine the proportion of AUS with a follow-up of lymphocytic thyroiditis, and if features could be identified that were characteristic of thyroiditis-associated atypia, allowing for increased comfort in the diagnosis of lymphocytic thyroiditis and a decrease in AUS. Materials and Methods: The pathology database was searched for thyroid FNA’s with an interpretation of AUS from the implementation of the Bethesda system in 2010 to 2013. The AUS rate was determined, and cytologic and/or surgical follow-up was identified. Original and follow-up slides were reviewed. Results: 86 AUS cases (6% of total thyroid FNA) were identified (61 with cytologic and/or surgical follow-up) with 61% having benign follow-up, 30% malignant follow-up, and 6% remaining as AUS on follow-up. 15% had a diagnosis of Hashimoto’s or lymphocytic thyroiditis alone (4 cases), with papillary thyroid carcinoma (PTC, 2 cases), or with incidental microcarcinoma (3 cases, PTC felt not to be represented on review of smears). Features that led to an AUS interpretation in the setting of thyroiditis were identified, including nuclear enlargement, elongation, crowding and grooves (as seen in Figure 1). Features supporting thyroiditis-associated atypia included degenerated cytoplasm, coarse chromatin, and prominent central nucleoli. Sparse malignant cells admixed with oncocytes and a polymorphous lymphoid population, including large immature lymphs, inhibited definite diagnosis in 2 cases where PTC co-existed with Hashimoto’s. Conclusions: We found an AUS rate of 6%, with 15% associated with lymphocytic thyroiditis. Increased recognition of these sometimes subtle features could lead to a decrease in the overall AUS rate.

Primary inflammatory malignant fibrous histiocytoma of the breast: A case report of an unusual variant and review of the literature

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma of adults, but its presence in the breast is rare. We report a case of primary inflammatory MFH in a 72-year-old Caucasian female with no previous medical history and no prior radiation exposure. She presented with a palpable mass that was suspicious for malignancy on mammography. Histologic evaluation of the core needle biopsy revealed sheets of large, pleomorphic neoplastic cells within a dense background of acute and chronic inflammatory cells. The neoplastic cells exhibited a moderate to abundant amount of finely vacuolated cytoplasm and atypical nuclei with vesicular nuclear chromatin and prominent nucleoli. Mitotic activity was readily identified, and foci of necrosis were noted. The neoplastic cells were immunoreactive with CD68, alpha 1-antitrypsin, alpha 1-antichymotrypsin, and vimentin. The diagnosis of MFH was rendered after thorough microscopic examination of the entire mass following mastectomy. MFH of the breast is a diagnosis of exclusion. The definitive treatment of MFH is surgical, either with wide local excision or total mastectomy. The roles of sentinel lymph node biopsy, axillary lymph node dissection, chemotherapy, and radiation have yet to be definitively clarified. The prognosis of MFH of the breast is generally poor.

Images in Endocrine Pathology: Psammomatoid Calcifications in Oncocytic Neoplasms of the Thyroid, a Potential Pitfall for Papillary Carcinoma

Pathological diagnosis was follicular adenoma with oncocytic (Hurthle cell) features (1.8 cm) and psammomatous calcifications. The left thyroid lobe contained a 1.8×1.4×1-cm, wellcircumscribed, solid, tan thyroid nodule. Histologically, the nodule was well demarcated from the adjacent normal thyroid parenchyma by a thin fibrous capsule (Fig. 1), without evidence of capsular or vascular invasion. The tumor consisted of a solid to microfollicular proliferation of Hurthle cells with characteristic abundant granular eosinophilic cytoplasm. Numerous microcalcifications were present, often within the lumens of the microfollicles (Fig. 1). Many of these microcalcifications were laminated, resembling psammoma bodies (Fig. 2). In other areas, microscopic droplets of dense and partially calcified colloid could be seen within follicle lumens (Fig. 3). The nuclei of the tumor cells were enlarged, round, and regular with coarse chromatin and prominent nucleoli, without longitudinal nuclear grooves or intranuclear pseudoinclusions. Immunostaining for HBME-1 and galectin-3 was negative.

Abstract 1086: MYC overexpression combined with Pten loss generates genomic instability and rapid metastasis in a new mouse model of lethal prostate adenocarcinoma.

Abstract There is a pressing need for animal models that recapitulate key pathological features of lethal human prostate adenocarcinoma. The availability of these models would facilitate studies to elucidate the molecular events underlying disease progression, and would be invaluable for evaluating new treatment efficacy. Within extant mouse models, metastasis is rare and typically occurs at an advanced age. Using a bacterial artificial chromosome-based transgenic approach, we generated mice in which Hoxb13 regulatory elements drive expression of human MYC (Hoxb13MYC+) or Cre recombinase (Hoxb13Cre+). Hoxb13Cre+ mice were bred to mice carrying floxed Pten (Ptenfl) alleles to generate focal loss of Pten in the prostate epithelium. We then generated mice carrying both the Hoxb13MYC+ and Hoxb13Cre+ transgenes that also harbored two Ptenfl alleles. Phenotypic analyses of Hoxb13MYC+|Hoxb13Cre+| Ptenfl/fl males revealed pervasive low-grade mouse-PIN (mPIN) in all prostate lobes emerging at two weeks of age that became pervasive that progressed to high-grade mPINby four weeks. The lesions bore hallmarks of human PIN including increased nuclear and nucleolar size and dispersed chromatin. Immunostaining revealed MYC and androgen receptor expression and focal Pten loss within the epithelial compartment. mPIN incidence high-gradewas higher in ventral and anterior lobes. By twelve weeks, lesions progressed to cribriform mPIN/intraductal carcinoma was widespread and scattered intraductal carcinoma lesions were observed. At sixteen weeks, in all animals, large frank invasive adenocarcinoma lesions involving multiple prostate lobes were was present as well as, and histological analyses confirmed the presence of invasive poorly differentiated adenocarcinoma. Interestingly, by 16 weeks, metastasis to pelvic and peritoneal lymph nodes occurred with 100% penetrance. In survival analyses, all Hoxb13MYC+|Hoxb13Cre+| Ptenfl/fl mice (N=12) reached criteria for euthanasia within 28 weeks. Liver and lung metastases were observed with high penetrance (>80%). In one case, metastatic spread to a thoracic vertebra was observed, which may represent the first hematogenous metastasis to bone in a mouse prostate cancer model. Copy number analyses using array-based comparative genomic hybridization revealed clonal gene gains and losses in primary prostate cancers and matched metastatic lesions, indicative of genomic instability. The incidence of aggressive cancer and the reproducible chronology of events will enable this model to serve as a robust platform to test strategies to interfere with disease initiation and progression. The lethal phenotype will permit analyses of potentially life extending therapies. In addition, these features will enable studies to dissect the pivotal molecular events that drive the stepwise progression/evolution of this disease. Citation Format: Gretchen K. Hubbard, Laura N. Mutton, May Khalili, Ryan P. McMullin, Jessica Hicks, Daniella Bianchi-Frias, Peter S. Nelson, Srinivasan Yegnasubramanian, Angelo M. De Marzo, Charles J. Bieberich. MYC overexpression combined with Pten loss generates genomic instability and rapid metastasis in a new mouse model of lethal prostate adenocarcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1086. doi:10.1158/1538-7445.AM2013-1086

Quantitative analysis of nucleolar chromatin distribution in the complex convoluted nucleoli of Didinium nasutum (Ciliophora)

We have earlier shown that the typical Didinium nasutum nucleolus is a complex convoluted branched domain, comprising a dense fibrillar component located at the periphery of the nucleolus and a granular component located in the central part. Here our main interest was to study quantitatively the spatial distribution of nucleolar chromatin structures in these convoluted nucleoli. There are no "classical" fibrillar centers in D.nasutum nucleoli. The spatial distribution of nucleolar chromatin bodies, which play the role of nucleolar organizers in the macronucleus of D.nasutum, was studied using 3D reconstructions based on serial ultrathin sections. The relative number of nucleolar chromatin bodies was determined in macronuclei of recently fed, starved D.nasutum cells and in resting cysts. This parameter is shown to correlate with the activity of the nucleolus. However, the relative number of nucleolar chromatin bodies in different regions of the same convoluted nucleolus is approximately the same. This finding suggests equal activity in different parts of the nucleolar domain and indicates the existence of some molecular mechanism enabling it to synchronize this activity in D. nasutum nucleoli. Our data show that D. nasutum nucleoli display bipartite structure. All nucleolar chromatin bodies are shown to be located outside of nucleoli, at the periphery of the fibrillar component.

Pulmonary neuroendocrine tumors: An entity in search of cytologic criteria

Pulmonary neuroendocrine tumors (PNET) are histologically subclassified into typical carcinoid (TC), atypical carcinoid (AC), large cell neuroendocrine carcinoma (LCNEC), and small cell carcinoma (SCLC). The criteria for subclassification in cytological specimens are not well defined. In this study, we reviewed histologically confirmed 18 TC, 8 AC, 10 LCNEC, and 10 SCLC cytologic specimens from 45 patients. The following features were reviewed: small clusters, geographic sheets, trabecular structures, pseudo-rosettes, single cells, doublets, triplets or short cords, papillary-like structures, capillary vasculatures, necrosis, smear background, cell size, cell pleomorphism, amount of cytoplasm, plasmacytoid cells, spindle cells, nuclear atypia, molding, palisading and smearing, chromatin textures, nucleoli, and mitotic figure count. Based on our results, geographic clusters and necrosis were often seen in LCNEC and SCLC; while AC only showed scattered single cell necrosis. TC and AC commonly exhibited trabecular structures. Papillary-like structures and capillary vasculature were only present in TC, AC, and LCNEC. Cells forming doublets, triplets, and short cords were more commonly seen in SCLC and rarely seen in other entities. Plasmacytoid and spindle cells were only seen in TC and AC. Nuclear smearing was not identified in TC, rare in AC, focally present in LCNEC and obvious in SCLC. Mitotic figures were nearly absent in TC, ≤5/10 HPF in AT, and ≥10/10 HPF in SCLC. LCNEC showed a wide span of mitotic count ranging between 2 and 16/10 HPF. In this study, we propose a set of cytological features that are essential for subclassification of PNETs in cytologic specimens.

Histología del ciclo reproductor de hembras del pejelagarto <i>Atractosteus tropicus</i> (Lepisosteiformes: Lepisosteidae) enTabasco, México

In Southeast Mexico, A. tropicus is a species with great ecological, economic, cultural and aquaculture value, however wild populations have diminished due to diverse anthropological causes. The objective of this study was to characterize the reproductive cycle of A. tropicus, with a description of complete gonad structure and the changes in germinal and somatic elements during oogenesis, for better management and use of this species. Six sexually mature females (N=72) were captured monthly with drag nets during one year cycle (October 2003-October 2004) in wild populations of Pomposu lagoon, municipality of Jalpa de Mendez, Tabasco, Mexico. Females were sacrificed by decapitation and the ovaries were processed by standard histological methods; the diameter of 10-20 oocytes taken at random was determined in different stages of development. Gonadosmatic index (GSI), gonadal volume (gV) and follicule diameter (fD) were determined monthly. Among results we could determine eight oogenesis developmental stages: I: chromatin nucleolus stage, II: early perinucleolus stage, III: mid perinucleolus stage, IV: advanced perinucleolus stage, V: early vitellogenesis stage, VI: mid vitellogenesis stage, VII) advanced vitellogenesis stage and VIII: final maturation stage. The reproductive cycle could be divided in four phases: 1: proliferative phase, II: initial maturation phase, III: late maturation phase, IV: regressing phase. Analysis of the data obtained from the IGS, gV and fD values, oogenesis stages and reproductive phases, indicate that in December previtellogenesis phase restarts, from March through July yolk deposition (vitellogenesis) occurs, and from August to November the maximum reproductive activity takes place. Contrasting this pattern with local environmental factors such as temperature and precipitation, we suggested that these may serve as an environmental activator in the development of oogenesis and spawning of this species.

Nucleolar chromatin organization at different activities of soybean root meristematic cell nucleoli.

Nucleolar chromatin, including nucleolus-associated chromatin as well as active and inactive condensed ribosomal DNA (rDNA) chromatin, derives mostly from secondary constrictions known as nucleolus organizer regions containing rDNA genes on nucleolus-forming chromosomes. This chromatin may occupy different nucleolar positions being in various condensation states which may imply different rDNA transcriptional competence. Sections of nucleoli originating from root meristematic cells of soybean seedlings grown at 25 °C (the control), then subjected to chilling stress (10 °C), and next transferred again to 25 °C (the recovery) were used to measure profile areas occupied by nucleolar condensed chromatin disclosed with sodium hydroxide methylation–acetylation plus uranyl acetate technique. The biggest total area of condensed chromatin was found in the nucleoli of chilled plants, while the smallest was found in those of recovered plants in relation to the amounts of chromatin in the control nucleoli. The condensed nucleolar chromatin, in the form of different-sized and different-shaped clumps, was mainly located in fibrillar centers. One can suppose that changes of condensed rDNA chromatin amounts might be a mechanism controlling the number of transcriptionally active rDNA genes as the nucleoli of plants grown under these experimental conditions show different transcriptional activity and morphology.

Histological assessment of gonad maturation in Labeo parvus (Teleostei: Cyprinidae) in Benin

A histological analysis was undertaken on the gonad development of Labeo parvus Boulenger 1902, a medium-sized cyprinid from the Ouémé River, Benin. Samples were collected monthly between April 2006 and March 2007 and were examined using routine macroscopic and histological techniques. Five macroscopic stages of gonad maturation were identified in the ovaries and testes and described histologically. Oocyte development was subdivided into five stages, based on the presence of chromatin nucleolus oocytes, perinucleolus oocytes, yolk vesicle oocytes, vitellogenic oocytes and mature oocytes. Four stages of spermatogenesis (spermatogonia, spermatocytes, spermatids and spermatozoa) were observed. Comparisons of macroscopic and histological observations revealed that the temporal patterns of maturation activity obtained from visual examination closely reflected the seasonal histological trend in gonad development. Histological characteristics of spent ovaries and testes were similar to those of immature fish, indicating that L. parvus were synchronous iteroparous spawners.

Histochemical Evaluation of Sexual maturation Phases in Solea solea Wild Marine Populations

The histological analyzes performed in gonad cells to verify the occurrence of changes in their anatomy is of crucial importance in order to characterize the dynamics of the gonads during the sexual maturation phase of its cells in specimens of wild marine populations. These histological data, together with other reproductive data, can be used in the monitoring of marine environments in which the Solea solea (Ishiba et al., 2008) lives, namely, the coastal waters of the Iberian Peninsula, Africa and Mediterranean sea (Ishiba et al., 2008). Therefore, the main objective of this study was to evaluate the several cellular types and its quantities and anatomies (Ishiba et al., 2008). The study was performed using a total of 19 specimens of the species Solea solea, collected between the months of January and March of 2011 in two different locations of the Portuguese coast (Aveiro and Leixões, Portugal). The gonad samples were fixated in Formalin-acetic acid-alcohol (FAA) and processed in accordance to the standard histology protocol (Culling et al., 1985). The slices of the gonads were colored with Haematoxylin and Eosin (H&E) (used in the study of the general structure of the gonads, as well as in the identification and localization of the different cellular types of the gonad epithelium). As a result of the study, we found 7 different types of gonad cells: I oogonia (It is not photographed ); II a Chromatin nucleolus oocytes (Fig.1. A); II b perinucleolar oocytes (Fig.1. B); III cortical alveoli oocytes (Fig.1. C); IV vitellogenic oocytes (Fig.1. D); V maturing oocyte (Fig.1. E); VI ovulated oocyte (Fig.1. F), (Hibiya, et al., 1995). The different cellular phases were found in all the gonad samples analyzed in this study and the results corresponded to those expected: a decrease in the size in the cells of the first cellular type, the oogonia and an increase in the size in the cells of all other cellular types found in the study. Histological and histochemical analyses of the Solea solea can be used in anatomic and pathological evaluations of the physiological condition of the animals, as stated previously for the muscles, where histological changes could be observed (such as: degeneration and atrophy of the muscle bundles). In the future, the analytical determination of histological and histochemical changes in the gonads of Solea solea, in conjunction with other analytical processes, such as in situ analyzes, can potentially be used to determine and accurately characterize the physiological condition of animals sampled in any natural environment.

The reproductive biology ofPlagioscion squamosissimus(Heckel, 1840) in the Pará River estuary (Amazon Estuary)

Summary This study describes the reproductive biology of the South American silver croaker Plagioscion squamosissimus (Heckel, 1840) in the ParaRiver estuary. Data were collected bimonthly from June 2007 to May 2008. In all, 334 specimens were examined. The gonads were processed with histological techniques, and the ovaries were subjected to morphometric analysis. The length at first maturity (L50) values were 16.14 and 21.43 cm total length for females and males, respectively. The sex ratio based on the total number of individuals favoured the females (1.11 females: one male). Macroscopi- cally, the gonads were classified as immature (A), maturing (B), mature (C) and spent (D). Microscopically, four germ cell types were distinguished based on the development of the ovaries. Chromatin nucleolus (I), perinucleolar (II), cortical alveoli (III) and full-vitellogenic (IV) oocytes were observed in all ovarian stages, except that of the mature individuals which showed the largest number of full-vitellogenic oocytes (IV), with a mean diameter of 565.4 l m( ±147.4). Substantial percentages of individual P. squamosissimus were found to be in a reproductive condition. Reproductive activity was recorded throughout the year in the ParaRiver estuary, pri- marily in February/March and August/September.

Ossifying fibromyxoid tumor — Diagnostic challenge for a cytopathologist

Ossifying fibromyxoid tumor — Diagnostic challenge for a cytopathologist

Development of the follicle complex and oocyte staging in red drum, sciaenops ocellatus linnaeus, 1776 (perciformes, sciaenidae)

Pelagic egg development in red drum, Sciaenops ocellatus, is described using tiered staging. Based on mitosis and meiosis, there are five periods: Mitosis of Oogonia, Active Meiosis I, Arrested Meiosis I, Active Meiosis II, and Arrested Meiosis II. The Periods are divided into six stages: Mitotic Division of Oogonia, Chromatin Nucleolus, Primary Growth, Secondary Growth, Oocyte Maturation and Ovulation. The Chromatin Nucleolus Stage is divided into four steps: Leptotene, Zygotene, Pachytene, and Early Diplotene. Oocytes in the last step possess one nucleolus, dispersed chromatin with forming lampbrush chromosomes and lack basophilic ooplasm. The Primary Growth Stage, characterized by basophilic ooplasm and absence of yolk in oocytes, is divided into five steps: One-Nucleolus, Multiple Nucleoli, Perinucleolar, Oil Droplets, and Cortical Alveolar. During primary growth, the Balbiani body develops from nuage, enlarges and disperses throughout the ooplasm as both endoplasmic reticulum and Golgi develop within it. Secondary growth or vitellogenesis has three steps: Early Secondary Growth, Late Secondary Growth and Full-Grown. The Oocyte Maturation Stage, including ooplasmic and germinal vesicle maturation, has four steps: Eccentric Germinal Vesicle, Germinal Vesicle Migration, Germinal Vesicle Breakdown and Resumption of Meiosis when complete yolk hydration occurs. The period is Arrested Meiosis II. When folliculogenesis is completed, the ovarian follicle, an oocyte and encompassing follicle cells, is surrounded by a basement membrane and developing theca, all forming a follicle complex. After ovulation, a newly defined postovulatory follicle complex remains attached to the germinal epithelium. It is composed of a basement membrane that separates the postovulatory follicle from the postovulatory theca. Arrested Meiosis I encompasses primary and secondary growth (vitellogenesis) and includes most of oocyte maturation until the resumption of meiosis (Active Meiosis II). The last stage, Ovulation, is the emergence of the oocyte from the follicle when it becomes an egg or ovum.

Ovarian degeneration during the female-to-male sex change in the protogynous hermaphroditic fish, Halichoeres poecilopterus

Halichoeres poecilopterus (Labridae) is a protogynous, hermaphroditic fish common in temperate waters around Japan. Although oocyte degeneration is an established event at the onset of sex change, there is little information on the process. We examined cell numbers and proportional ratios of ovarian germ cells in sex-changing gonads of H. poecilopterus. This confirmed a lack of YV (yolk vesicle stage) and Y (yolk stage) oocytes, a rapid decrease of P (perinucleolus stage) oocytes, and a slight increase of CN (before/at chromatin nucleolus stage) germ cells. We discuss gonadal conditions necessary for the protogynous sex change of H. poecilopterus.

Disseminated Neuroendocrine Carcinoma in a Pediatric Patient

A previously healthy 16-year-old female presented with 1-month history of fever, cough, extremity pain, left upper quadrant pain, and night sweats. Imaging studies revealed mediastinal lymphadenopathy, lung and liver masses, and bony lesions. Liver and bone marrow biopsies revealed small tumor cells with a high nuclear cytoplasmic ratio, stippled chromatin, and inconspicuous nucleoli surrounded by bands of collagen. Immunohistochemically, the tumor cells were positive for epithelial (epithelial membrane antigen and cytokeratin AE1/AE3) and neuroendocrine markers (chromogranin and synaptophysin), and negative for other antigens tested, including vimentin, desmin, CD99, and WT-1. The morphologic features and immunohistochemical profile was consistent with neuroendocrine carcinoma. Despite several chemotherapeutic regimens, the patient had progressive disease and enrolled in a phase 1 trial. Thorough histopathologic evaluation, including immunohistochemical stains is a crucial component for diagnosing this rare, aggressive tumor in children and adolescents.

Relative position of nucleolar chromatin and nucleolar components in ciliate Didinium nasutum somatic nuclei

According to our computer modeling data obtained earlier, nucleoli in interphase ciliates Didinium nasutum are complex netlike structures, in which the trabeculumor lamella-shaped fibrillar component is located on the periphery, and the granular component in the central part of the nucleolus. Chromatin bodies connected with nucleoli act as the nucleolar organizers in D. nasutum. In the present work, the arrangement of all chromatin bodies, which could correspond to nucleolar organizers by morphological criteria, is studied by means of a 3D-reconstruction. It is shown that all of these chromatin bodies are localized outside the nucleoli, on the fibrillar component’s periphery. Even those chromatin bodies which appeared to be completely surrounded by the fibrillar nucleolar component on single ultrathin sections are actually settled down in nucleolus cavities open to the nucleoplasm. This proves that the RNA processing in D. nasutum nucleoli is directed toward the center of nucleoli, where the granular component is located. The analysis of the nucleolar chromatin distribution made it possible to conclude that different parts of the complex interfase netlike nucleoli of D. nasutum have approximately the same activity.