FAK is required for the assembly of podosome rosettes

Podosomes are dynamic actin-enriched membrane structures that play an important role in invasive cell motility and extracellular matrix degradation. They are often found to assemble into large rosettelike structures in highly invasive cells. However, the mechanism of this assembly remains obscure. In this study, we identified focal adhesion kinase (FAK) as a key molecule necessary for assembly. Moreover, phosphorylation of p130Cas and suppression of Rho signaling by FAK were found to be important for FAK to induce the assembly of podosome rosettes. Finally, we found that suppression of vimentin intermediate filaments by FAK facilitates the assembly of podosome rosettes. Collectively, our results strongly suggest a link between FAK, podosome rosettes, and tumor invasion and unveil a negative role for Rho signaling and vimentin filaments in podosome rosette assembly.     

Hemangioendothelioma. Cytologic appearances in two cases presenting with multiple soft tissue and bone lesions

Two cases of hemangioendothelioma were detected by fine needle aspiration cytology in two women presenting with multiple soft tissue and bone lesions. The aspirates were hemorrhagic, and the smears showed mostly dissociated and predominantly monomorphic tumor cells. Focal rosettelike clustering of tumor cells was also present. A prominent cytologic feature of these two cases of hemangioendothelioma was the close association of tumor cells with endothelium-lined vascular structures, a pattern that can be seen in other sarcomas and sometimes in malignant epithelial tumors.     

Peripheral primitive neuroectodermal tumor of the vulva: report of a case with imprint cytology.

BACKGROUND: Peripheral primitive neuroectodermal tumor (PNET) of the vulva is an extremely rare disease, and, to our knowledge, only two cases have been previously reported. CASE: A 45-year-old woman presented with a mass in the right labium major. Three years after removal of the tumor, she noticed a new lesion in the same place and underwent a partial vulvectomy. The imprint cytology of the recurrent tumor showed a monomorphic appearance, composed of small round cells with scant cytoplasm against a hemorrhagic background. These tumor cells were loosely connective, but rosettelike structures were observed focally. On pathologic examination, the neoplasm was composed of small round tumor cells showing sinusoidal, diffuse or micropapillary growth. Immunohistochemically, the neoplastic cells stained positively for neuron-specific enolase, vimentin and HBA 71 and negatively for cytokeratin, HBA 45 and muscle-specific actin. The morphologic characteristics of the disease were well expressed in the imprint cytology, and this influenced the selection of immunohistochemical studies. CONCLUSION: Cytologic examination for vulvar tumors, even imprint cytology, can be a useful tool in obtaining an accurate pathologic diagnosis of a rare disease, such as peripheral PNET.     

Basal cell adenocarcinoma of the salivary gland: report of a case with morphology on fine needle aspiration cytology

BACKGROUND: Basal cell adenocarcinoma of the parotid is rare and prone to recur. CASE: A 54-year-old woman had a history of afacial mass 12 years earlier that had been excised and was diagnosed as low grade adenocarcinoma of the parotid. Over the years, the patient had multiple local and lymph node recurrences. Histology of the excised local recurrent tumor showed basal cell adenocarcinoma, and FNAC of a separate recurrent nodule was performed. The aspirate showed moderate cellularity of basaloid cells with mildly pleomorphic nuclei, small nucleoli and occasional mitotic figures. The cells were mostly single, but some formed clusters with a rosettelike pattern of tumor cells surrounding central eosinophilic globules. A second, less prominent population of smaller cells with dark-staining nuclei was also noted. The differential diagnosis included adenoid cystic carcinoma, polymorphous low grade adenocarcinoma, and basal cell and pleomorphic adenoma. CONCLUSION: The cytologic features of basal cell adenocarcinoma are not distinctive, but the presence of two cell populations with moderate pleomorphism and a rosettelike pattern with central, eosinophilic globules may assist with its differentiation from other salivary gland neoplasms.     

Cytologic features of central neurocytomas of the brain. A report of three cases

BACKGROUND: Although cytologic smears are major tools for intraoperative diagnosis of intracranial tumors, cytologic features of central neurocytoma, a tumor that has been recognized for only about 15 years, have not been described. CASES: Typical central neurocytomas were encountered in three patients: 40 years old/M, 44/M and 31/F. Intraoperative cytologic smears were reviewed, and all tumors were subsequently examined by conventional histology, immunohistology and, in one case, electron microscopy. The important cytologic appearances were sheets of round cells with finely stippled nuclear chromatin and perinuclear haloes. Calcospherites, neuropil islands and rosettelike structures were focally encountered. The background neuropil was finely fibrillated, but the tumor cells possessed no appreciable cellular processes. CONCLUSION: Central neurocytomas possess distinct cytologic features that help with the intraoperative distinction from oligodendrogliomas and other intraventricular tumors. A combined radiologic and morphologic approach to the diagnosis of this tumor is advised.     

Cytology of hemangioendothelioma

The cytologic appearance is described of hemangioendothelioma in fine needle aspiration smears from a young male who presented with recurring bilateral lesions within two years. The cytomorphologic pattern was extremely cellular, with a monomorphic population of cells, some of which showed a tendency to form rosettelike or pseudoacinar formations.     

Intraoperative cytologic crush preparation findings in craniopharyngioma: a study of 72 cases

OBJECTIVE: To describe the intraoperative crush preparation and the cytologic features of craniopharyngioma and the differential diagnosis. STUDY DESIGN: Twelve cases of craniopharyngioma were diagnosed by crush preparation cytology in the Department of Pathology, Shiraz Medical School, and formed the basis of this study. The patients' ages ranged from 7 to 43 years; 3 were female and 9 male. The cytologic findings together with the histologic findings were studied. RESULTS: All cases had a high yield of cells, consisting of honeycomb sheets of epithelial cells with and without palisading rows of cells, papillary clusters, squamous cell clusters, anucleated squames, calcification, multinucleated giant cells, cholesterol crystals, glandular or rosettelike structures, ciliated columnar cells and spindle cells. The smears were diagnosed as suggestive of craniopharyngioma. Histologic sections confirmed the cytologic diagnoses. CONCLUSION: Intraoperative cytologic crush preparation findings are helpful in the diagnosis of craniopharyngioma, when combined with clinical information. Crush preparation cytology is important in the diagnosis of central nervous system tumors.     

Chromonema and chromomere

A study of ultrathin sections of normal Chinese hamster cells and cells treated with decreasing concentrations of bivalent cations (Ca²⁺ and Mg²⁺) in situ revealed several discrete levels of compaction of DNA-nucleoprotein (DNP) fibrils in mitotic chromosomes and the chromatin of interphase nuclei. At concentrations ranging from 3 mM CaCl₂ and 1 mM MgCl₂ to ten times less, the chromosomes are found to contain fibrous elements (chromonemata) about 100 nm in diameter. As Ca²⁺ concentration is gradually decreased to 0.2–0.1 mM, the chromosomes decondense into a number of discrete chromatin structures, the chromomeres. As decondensation proceeds, these chromomeres acquire a rosettelike structure with DNP fibrils radiating from an electron-dense core. Upon complete decondensation of chromosomes, individual chromomeres persist only in the centromeric regions. The following levels of DNP compaction in mitotic chromosomes are suggested: a 10-nm nucleosomal fibril, a 25-nm nucleomeric fibril, and the chromonema, a fibrous structure, about 100 nm in diameter, composed of chromomeres. Interphase nuclei also contain structures which are morphologically similar to the chromomeres of mitotic chromosomes.     

One-sided ejaculation of echidna sperm bundles

We report for the first time an unusual ejaculatory mechanism in the short-beaked echidna in which each side of the bilaterally symmetrical, rosettelike glans penis is used alternately, with the other being shut down. This is unparalleled in mammals but is reminiscent of the use of hemipenes in squamate reptiles, providing further reproductive evidence of a sauropsidian lineage in the Monotremata. Further, we describe the occurrence of motile sperm bundles in ejaculated echidna semen and provide scanning electron micrographs of their morphology. Sperm bundling appears to confer increased sperm motility, which may provide the potential for sperm competition between males.     

Electron microscopic observations on sperm entry and pronuclear formation in naked eggs of the rose bitterling in polyspermic fertilization

Unfertilized eggs of the rose bitterling (Rhodeus ocellatus ocellatus) were squeezed out of females that had an elongated ovipositor and were dechorionated mechanically with fine forceps in physiological saline. The dechorionated eggs were transferred into fresh water then inseminated at once by spermatozoa of the same species. A large number of spermatozoa was found on the surface of eggs that had not yet had cortical reaction following insemination. The surface of the naked eggs responded by formation of many small cytoplasmic protrusions (viz., fertilization cones) at sperm attachment sites. The formed fertilization cones were rosettelike structures formed by the aggregation of some bleblike swellings devoid of microvilli and microplicae. About 10 min after insemination, the fertilization cones retracted, but marks of their presence characterized by less microvilli and microplicae remained in the eggs 15 min after insemination. Many spermatozoa penetrated into the cytoplasm of each naked egg. The sperm nuclear envelope disappeared by means of vesiculation resulting from fusion of the inner and outer membranes. The sperm nucleus decondensed and developed into a larger male pronucleus. Smooth-surfaced vesicles surrounded the decondensing sperm nucleus and formed the new male pronuclear envelope. Sperm mitochondria and flagella were found in the egg 15 min after insemination. The response of the egg surface to sperm entry and pronucleus formation are discussed.     

A new species of Plasmodium from Malagasy vangas

During a recent examination of blood smears from Malagasy birds, a species of avian Plasmodium unlike those currently known was observed. All infected birds were members of the Vangidae, which is endemic to Madagascar and the Comoro Islands. Plasmodium parvulum n. sp. is described, and classified as a member of the subgenus Haemamoeba because of gametocyte and schizont shape, displacement of the host cell nucleus, as well as distortion of the host cell. Round, rosettelike schizonts with 6-8 merozoites, clumped refractile granules, and little cytoplasm were observed. Both schizonts and mature, round gametocytes rotated and displaced the erythrocyte nucleus. A brief comparison to P. relictum is included.     

Fine needle aspiration cytology of sclerosing lobular hyperplasia of the breast: a case report

BACKGROUND: Sclerosing lobular hyperplasia presenting as a palpable, circumscribed nodular mass in a young female's breast is characterized histologically by prominent hyperplasia of the lobules and sclerosis of the intralobular connective tissue. The cytomorphologic features and differential diagnosis of the lesion are presented. CASE: A 14-year-old female presented with a painless, progressively increasing, nodular, firm, mobile lump measuring 5 x 5 cm in the right breast. The clinical and radiologic diagnosis was fibroadenoma. Fine needle aspiration smears showed a clean background with uniform, round to oval epithelial cells in flat sheets, round clusters and rosettelike (acinar) arrangements. A few naked nuclei were present, while stromal fragments were not seen. CONCLUSION: When analyzed in the context of the clinical findings, the cytologic features of sclerosing lobular hyperplasia help to differentiate it from other benign palpable nodular lesions of the juvenile breast.     

Cystic adult ovarian granulosa cell tumor as a potential source of false negative diagnosis in ovarian cytology. A case report

BACKGROUND: Adult granulosa cell tumors (AGCT), unilocular or multilocular, with thin-walled cysts, are extremely rare. They can be erroneously diagnosed as follicular cysts by sonography and fine needle aspiration and therefore may be a source of false negative results. CASE: Laparoscopy was performed on a 29-year-old woman in whom a cystic ovarian mass, probably benign, was diagnosed by transvaginal sonography. The smears obtained from the cyst revealed a moderate amount of regular, small cells with scant cytoplasm and round to oval nuclei with finely granular chromatin without longitudinal grooves. These granulosa cells were arranged singly and in small groups. Very scarce cellular aggregates, microfollicular or rosettelike, some containing amorphous material and resembling Call-Exner bodies, were identified. Histologic study of the cystic wall confirmed the diagnosis of multilocular cystic AGCT with a microfollicular pattern. CONCLUSION: The finding of a moderate to abundant amount of regular granulosa cells, with or without nuclear longitudinal grooves, during cytologic examination of ovarian cysts considered benign by ultrasonography requires a careful search for microfollicular differentiation and Call-Exner bodies due to the rare but possible occurrence of cystic AGCT.     

Structural and functional characterization of the poliovirus replication complex.

Two populations of membrane-bound replication complexes were isolated from poliovirus-infected HEp-2 cells by sucrose gradient centrifugation. The two fractions show similar ultrastructural features: the replication complex is enclosed in a rosettelike shell of virus-induced vesicles and contains a very tightly packed second membrane system (compact membranes). The vesicular fraction, which bands in 30% sucrose, contains replicative intermediate (RI) and 36S RNA. The fraction banding in 45% sucrose contains only minute amounts of RI and contains mainly 36S RNA, two-thirds of which is encapsidated. In vitro, the two fractions show similar RNA synthesizing capacities and produce 36S plus-strand RNA. Dissolving the membranes within and around synthetically active replication complexes with sodium deoxycholate abolishes the completion of 36S RNA but still allows elongation in the RI. Our findings suggest an architecture of the replication complex that has the nascent plus strands on the RI enclosed in the compact membranes and the replication forks wrapped additionally in protein. Plus-strand RNA can be localized by in situ hybridization with a biotinylated riboprobe between the replication complex and the rosette of the virus-induced vesicles. It was found that the progeny RNA strands are set free soon after completion from the replication complex at the sites where the compact membranes within the replication complex are in close contact with the surrounding virus-induced vesicles.     

Follicular variant of papillary carcinoma of the thyroid. A cytologic study of 15 cases

OBJECTIVE: To study the cytologic findings of follicular variant of papillary thyroid carcinoma (FVPTC) and to compare them with the cytologic findings on other thyroid lesions. STUDY DESIGN: The study group consisted of aspirate smears from 15 cases of histologically proven FVPTC. The control group consisted of 152 cases, including adenomatous colloid goiter (70), usual papillary carcinoma (40), follicular adenoma (30), Hürthle cell neoplasm (7) and medullary carcinoma (5). RESULTS: The smears of FVPTC revealed numerous colloid balls in the background, multilayered microfollicles (rosettes), numerous nuclear grooves and inclusions in the monolayer sheets of follicular cells, very rare giant cells, absence of calcification and papillary clusters. Rosettelike microfollicles and numerous colloid balls were not seen in the control group. CONCLUSION: The combination of numerous colloid balls and rosettelike microfollicles was frequently seen in FVPTC. This combination was not observed in the control group.     

A systematic search method for the identification of tightly packed transmembrane parallel alpha-helices

Membrane proteins play a major role in number of biological processes such as signaling pathways. The determination of the three-dimensional structure of these proteins is increasingly important for our understanding of their structure-function relationships. Due to the difficulty in isolating membrane proteins for X-ray diffraction studies, computational techniques are being developed to generate the 3D structures of TM domains. Here, we present a systematic search method for the identification of energetically favorable and tightly packed transmembrane parallel alpha-helices. The first step in our systematic search method is the generation of 3D models for pairs of parallel helix bundles with all possible orientations followed by an energy-based filter to eliminate structures with severe non-bonded contacts. Then, a RMS-based filter was used to cluster these structures into families. Furthermore, these dimers were energy minimized using molecular mechanics force field. Finally, we identified the tightly packed parallel alpha-helices by using an interface surface area. To validate our search method, we compared our predicted GlycophorinA dimer structures with the reported NMR structures. With our search method, we are able to reproduce NMR structures of GPA with 0.9A RMSD. In addition, by considering the reported mutational data on GxxxG motif interactions, twenty percent of our predicted dimers are within in the 2.0A RMSD. The dimers obtained from our method were used to generate parallel trimeric and tetramer TM structures of GPA and found that the structure of GPA might exist only in a dimer form as reported earlier.     

A Systematic Search Method for the Identification of Tightly Packed Transmembrane Parallel α-Helices

Abstract

Membrane proteins play a major role in number of biological processes such as signaling pathways. The determination of the three-dimensional structure of these proteins is increasingly important for our understanding of their structure-function relationships. Due to the difficulty in isolating membrane proteins for X-ray diffraction studies, computational techniques are being developed to generate the 3D structures of TM domains. Here, we present a systematic search method for the identification of energetically favorable and tightly packed transmembrane parallel α-helices. The first step in our systematic search method is the generation of 3D models for pairs of parallel helix bundles with all possible orientations followed by an energy-based filter to eliminate structures with severe non-bonded contacts. Then, a RMS-based filter was used to cluster these structures into families. Furthermore, these dimers were energy minimized using molecular mechanics force field. Finally, we identified the tightly packed parallel α-helices by using an interface surface area. To validate our search method, we compared our predicted GlycophorinA dimer structures with the reported NMR structures. With our search method, we are able to reproduce NMR structures of GPA with 0.9Å RMSD. In addition, by considering the reported mutational data on GxxxG motif interactions, twenty percent of our predicted dimers are within in the 2.0Å RMSD. The dimers obtained from our method were used to generate parallel trimeric and tetramer TM structures of GPA and found that the structure of GPA might exist only in a dimer form as reported earlier.     

Exfoliative cytologic findings of primary pulmonary adenoid cystic carcinom: a report of 2 cases with a review of the cytologic features

BACKGROUND: Adenoid cystic carcinoma is a very rare primary pulmonary neoplasm. Cytologic findings of pulmonary washing and brushing in 2 cases of primary bronchial adenoid cystic carcinoma with special histologic features are described, with an emphasis on some points that have not been reported previously, together with the diagnostic pitfalls. CASES: Two cases of primary adenoid cystic carcinoma of the lung were diagnosed on exfoliative cytology. The patients' ages were 55 and 65 years old. Cytologic findings included large and small clusters of small cells in both 2 and 3 dimensions with occasional cystlike spaces containing mucoid material. The cells were arranged in spherical, cylindrical, basaloid and rosettelike arrangements. There were also abundant small and large mucoid globules, cylinders of homogeneous, acellular, mucous material and "cannon balls." Cytoplasmic and intranuclear round inclusions were noted in case 1. Rare findings of nuclear molding were noted. In case 2, chondromyxoid material and a bimorphic population of tumor cells caused diagnostic confusion with other salivary gland-type tumors of the lung. CONCLUSION: These cases showed characteristic cytologic findings of adenoid cystic carcinoma together with rare findings of intracellular and extracellular inclusionlike bodies, myxochondroid material, bimorphic populations and nuclear molding, which can cause diagnostic confusion with other lung tumors.     

Morphologische Untersuchungen zur Proliferationskinetik der Mäusehaut

Zusammenfassung 1. Es wird eine Methode zur Herstellung, Montierung und Färbung von epidermalen Häutchenpräparaten zur dreidimensionalen Analyse des Epidermis-Aufbaues beschrieben. Eine Kombination mit der Histoautoradiographie ist bedingt möglich. Damit ist eine Basis für weitere Untersuchungen mit neuer Fragestellung geschaffen. 2. Die untersuchten Objekte Mäuseohr und Rückenhaut zeigen eine bisher unbekannte, auffallende Musterbildung mit Zuordnung bestimmter interfollikulärer basaler Gruppen zu Zellen des Stratum spinosum und des Stratum corneum. Es handelt sich um rosettenähnliche Gebilde aus mehreren peripheren Basalzellen und meist einer zentralen Spinosumzelle. 3. Die Bedeutung der Befunde für die normale wie für die pathologische Regeneration und Neoplasie der Epidermis ist offen. Es werden Beziehungen zum Regenerationsmodus und damit zur Proliferationskinetik der Epidermis diskutiert. In diesem Zusammenhang sind die Untersuchungen auch für die Humanpathologie relevant.

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Morphologic investigations of the proliferation kinetics of the mouse epidermisStandardized methods and results

Summary 1. A method for the preparation, mounting, and staining of thin preparations of mouse epidermis is described, which allows a three-dimensional analysis of epidermal structure. A limited combination of this technique with histo-autoradiography is possible, thereby presenting a broader basis for further investigations. 2. Both ear and back skin show a striking, previously unrecognized pattern of organization, in which definite interfollicular basal cell groups are oriented towards cells of the stratum spinosum and stratum corneum. A rosettelike picture of many peripheral basal cells and, in most instances, a central spinosum cell is found. 3. The significance of our findings for normal and pathological regenerations as well as neoplasia of the epidermis remains open. We discuss relationships to the mode of regeneration and thus the kinetics of proliferation in the epidermis. Our investigations are also relevant for human pathology in this regard.

Meinem Vater Kurt Goerttler zur Vollendung des 75. Lebensjahres herzlichst zugeeignet.