Rosette-like Appearance Research Articles

Platelet satellitism: unusual cause of spurious thrombocytopenia

Platelet satellitism (PS) is defined as adherence of platelets on the surface of polymorphonuclear leucocytes and imparting a rosette-like appearance especially in ethylenediaminetetraacetic acid (EDTA) whole blood samples. We here present a case of spurious thrombocytopenia resulting from florid platelet adherence on the surface of neutrophils.

Systematic revision of the genus Reinboldiella (Ceramiaceae, Rhodophyta) from Taiwan based on comparative morphology and rbcL sequence analyses, including two new species of Reinboldiella

ABSTRACTThe genus Reinboldiella essentially consists of tiny, membranous blades, epiphytic on benthic red algae, with a wide distribution in the north-western Pacific Ocean (Taiwan, Korea and Japan). In this study, we re-examined the generitype R. schmitziana from Taiwan and neighbouring islands. Two new species of Reinboldiella, R. orientalis sp. nov. and R. taiwanensis sp. nov. are recognized from Taiwan based on comparative morphological studies and molecular analyses of RuBisCO large subunit (rbcL) gene sequences. Reinboldiella orientalis is characterized by its rosette-like appearance, with both erect and prostrate, membranous flat blades whereas R. taiwanensis is distinguishable by mainly consisting of erect, membranous blades with few, short prostrate blades in basal parts of the thalli. Thalli of R. schmitziana also have a rosette-like appearance, but their erect flat blades have cylindrical bases or stipes. The rbcL phylogenetic analyses also support the separation of R.‘schmitziana’ from Taiwan and R. schmitziana from Japan and Korea.

New ultrastructural observations of human oocyte smooth endoplasmic reticulum tubular aggregates and cortical reaction: update on the molecular mechanisms involved

IntroductionThe ultrastructure of the human mature metaphase-II oocyte before and after the cortical reaction has been previously described. However, we found a new vesicular aggregate associated with smooth endoplasmic reticulum tubular aggregates (aSERT) and new observations regarding the cortical reaction. ObjectivesTo describe at the ultrastructural level a novel vesicle aggregate associated with aSERT and new observations regarding the cortical reaction. Materials and methodsDonated, surplus mature oocytes were processed for transmission electron microscopy immediately after recover. Calcium detection was performed using the pyroantimonate technique. The cortical reaction was artificially induced by ionophore treatment. ResultsWe observed an accumulation of small vesicles at the periphery of aSERT. At high magnification these were composed by small pale vesicles coated by tiny vesicles, with associated dense materials, giving a rosette-like appearance. Adjacent to these there was another group of small dense vesicles incompletely coated by similar tiny vesicles. Using calcium detection at the ultrastructural level, antimonate deposits were observed in the tubules of aSERT and in the surrounding mitochondria but not in the rosette-like structures. Regarding cortical vesicles, although most previous studies described their contents as homogeneous dense, others referred the presence of another type of cortical vesicles whose contents were moderate dense. Using ionophore oocyte activation, we observed that moderate dense cortical vesicles may correspond to a progressive swelling of the dense cortical vesicles prior to exocytosis. ConclusionsWe describe a novel vesicle aggregate associated to aSERT and new observations on the remodeling of cortical vesicles before exocytosis.

Bulking Duration and Daminozide Affect Growth and Flowering of Achillea בCoronation Gold’

A study was conducted to determine the effects of bulking duration and the plant growth retardant daminozide on plant growth and flowering of greenhouse-grown ‘Coronation Gold’ yarrow (Achillea בCoronation Gold’). Single-shoot liners of yarrow were transplanted on October 14 and December 2, 2010, into 15 cm (6 in) containers and bulked for 4, 6, 8, or 10 weeks prior to exposure to night-interrupted lighting (NIL). Increasing the bulking duration increased the number of shortened, thickened stems of rosette-like appearance, or offsets, that had developed from the base of the main stem by the end of bulking by 100 to 367% and reduced days to first and five open inflorescences, hereafter referred to as flowers, from the beginning of NIL by 13 to 16 days and 10 to 20 days for the October and December potting dates, respectively. Increasing the bulking duration increased flower and flower bud number by 67 and 25% in the October 14 and December 2 potting dates, respectively. Therefore, more flowers and flower buds formed on yarrow when potted early, compared to late potting. Lengths of the first five open flower stems were inconsistent and minimally affected by bulking duration. In a repeat of the experiment potted on December 2 using the same bulking treatments, 5,000 ppm of daminozide was applied as a foliar spray when half the plants in a bulking duration had begun to elongate and was reapplied 1 week later. Daminozide application decreased stem length at first open flower by 20 to 43%, but increased days to first flower and five open flowers by 6 and 8 days, respectively. As in the first experiment, increasing the bulking duration increased the number of offsets and flower and flower bud number and reduced days to first and five open flowers.

The gametogenic cycle and life history ofNicolea uspiana(Polychaeta: Terebellidae) on the south-east coast of Brazil

The gametogenic cycle and life history ofNicolea uspiana(Nogueira, 2003) (Polychaeta: Terebellidae) was studied by taking monthly samples over a 13 month period. Each month, 10 females were sorted; 50 oocytes were removed from the coelom of each specimen, and the maximum diameter was determined. Additionally, 10 males were sorted and 100 gametes were randomly selected from each specimen to evaluate their shape and maturation stage. This species is gonochoric and exhibits slight external sexual dimorphism (in the shape of the nephridial papillae). The sex-ratio ofN. uspianawas 2.4 male for each female. The initial gametic stages of both sexes are produced in special structures called nephromixia. Oogenesis is extra-ovarian, and the germ cells are clumped and surrounded by follicle cells. These cells are ovulated into the coelomic fluid, and yolk synthesis occurs in this cavity. The maximum diameter of oocytes measured, 225 µm, showed that these eggs fall into the size-range for lecithotrophy. Furthermore,N. uspianais an iteroparous species, as the mature individuals can breed several times during their lifetime. Male gonads release germ cells early in development, and sperm maturation also occurs in the coelomic fluid. The male gametes consist of flattened plaques of germ cells attached on their anterior part by a cytophore assuming a rosette-like appearance. Following maturation of the male cells, the spermatids produce arrays of stiffly vibratile tails, assuming a morula shape. The reproductive patterns and life history of the terebellids are also discussed.

Platelet satellitism: a rare, interesting, in vitro phenomenon.

Platelet satellitism is a unique, uncommon, in vitro phenomenon seen in peripheral blood smears prepared from EDTA-mixed blood. This is seen in the form of platelets adhering to polymorphonuclear leucocytes imparting a rosette-like appearance. There is no definite causal association with any disease. The cause may be immunological or non-immunological. Severe rosetting may lead to a misdiagnosis of thrombocytopenia unless peripheral smears are examined. Here, we describe a case of incidentally detected platelet satellitism in a healthy 48-year old male subject during a routine check-up.

Dual origin, development, and fate of bovine pancreatic islets.

Endocrine cells are evident at an early stage in bovine pancreatic development when the pancreas still consists of primitive epithelial cords. At this stage, the endocrine cells are interspersed between the precursor cells destined to form the ductulo-acinar trees of later exocrine lobules. We here demonstrate that, in bovine fetuses of crown rump length ≥11cm, the endocrine cells become increasingly segregated from the developing exocrine pancreas by assembly into two units that differ in histogenesis, architecture, and fate. Small numbers of 'perilobular giant islets' are distinguishable from larger numbers of 'intralobular small islets'. The two types of islets arise in parallel from the ends of the ductal tree. Aside from differences in number, location, and size, the giant and small islets differ in cellular composition (predominantly insulin-synthesising cells vs. mixtures of endocrine cells), morphology (epithelial trabeculae with gyriform and rosette-like appearance vs. compact circular arrangements of endocrine cells), and in their relationships to intrapancreatic ganglia and nerves. A further difference becomes apparent during the antenatal period; while the 'interlobular small islets' persist in the pancreata of calves and adult cattle, the perilobular giant islets are subject to regression, characterised by involution of the parenchyma, extensive haemorrhage, leukocyte infiltration (myeloid and T-cells) and progressive fibrotic replacement. In conclusion, epithelial precursor cells of the ductolo-acinar tree may give rise to populations of pancreatic islets with different histomorphology, cellular composition and fates. This should be taken into account when using these cells for the generation of pancreatic islets for transplantation therapy.

Spitz Nevus With Homer-Wright Rosette-Like Structures

To the Editors: Since its original description in 1948, the Spitz nevus remains one of the most controversial and diagnostically challenging entities in dermatopathology.1 Its morphological spectrum is wide, and reliable distinction from spitzoid melanoma is often difficult. Recognized histological variants include the pigmented spindle cell (Reed) nevus; the desmoplastic, halo, polypoid, hyalinized, angiomatous, granulomatous, myxomatous, pigmented epithelioid plexiform, tubular, pagetoid, combined, and intraepidermal Spitz nevus.2 Only 1 case of a Spitz nevus showing rosette-like structures has been described, and this pattern is not mentioned in any of the larger published series to date.3 We report a further case showing this unusual morphology with emphasis on distinction from invasive melanoma showing rosette-like structures. A 6-mm-diameter mole was excised from the lower back of a 29-year-old woman. Histological examination showed a circumscribed and symmetrical compound melanocytic lesion (Fig. 1). The junctional component was predominantly nested and composed of epithelioid melanocytes with spitzoid cytomorphological features, including abundant eosinophilic cytoplasm and vesicular nuclei with eosinophilic central nucleoli. Kamino body formation and junctional cleavage were present. Focal epidermal atrophy and intraepidermal ascent of scattered melanocytes were limited to the center of the lesion. The dermal component was cellular, and the predominant pattern was of epithelioid cells arranged in nests with a peripheral alignment of nuclei and centrally aggregated eosinophilic cytoplasm, resulting in a striking rosette-like appearance (Fig. 2). No central cystic spaces, lumina, or vascular structures were present, and the structures most closely resembled the Homer-Wright rosettes. This florid rosette-like morphology was present throughout the thickness of the lesion, making assessment of maturation with depth difficult (Fig. 3). Rare mitotic activity was present and confined to the upper half of the lesion. No atypical mitoses were observed. There was no expansile growth, nuclear pleomorphism, or hyperchromasia. By immunohistochemistry, there was diffuse S100 and Melan A expression within the melanocytes, and the mib-1 proliferative index was low. HMB-45 expression was confined to the junctional and superficial dermal aspect. A diagnosis of Spitz nevus with Homer-Wright rosette-like structures was rendered.FIGURE 1: Low-power view highlighting lesional symmetry and circumscription.FIGURE 2: Melanocytic nests within the dermis showing a peripheral rim of nuclei and centrally aggregated eosinophilic cytoplasm, resulting in a rosette-like appearance reminiscent of Homer-Wright rosettes.FIGURE 3: Assessment of maturation with depth is impaired by the florid rosette-like morphology extending throughout the thickness of the lesion.Rosette-like structures are a rare and poorly documented observation in melanocytic tumors. They occur most frequently in the setting of primary and metastatic melanoma, but their presence in benign melanocytic tumors is exceptional.4–8 Rosette formation has only been demonstrated in a proliferative nodule arising within a congenital nevus, and to our knowledge, there is only 1 previous report of a Spitz nevus showing rosette-like structures presenting on the knee of a 36-year-old white woman.3,9 Most frequently, the rosettes show a peripheral rim of nuclei with a central aggregate of eosinophilic cytoplasm lacking a central lumen or vessel resembling most closely the Homer-Wright rosettes seen in neuroblastoma and peripheral neuroectodermal tumor.3,6–9 The case presented here was remarkable for florid rosette formation affecting almost the entire lesion, including the deep aspect, resulting in a rather monotonous appearance of the dermal component and an impression of impaired maturation with depth. Extensive rosette formation in benign melanocytic lesions may appear alarming and may easily result in an erroneous diagnosis of invasive melanoma. This is of particular importance as distinguishing features may be subtle, as demonstrated recently in a case of a nevoid melanoma with rosette formation.7 Features in favor of a diagnosis of melanoma include the large lesional size and asymmetry, confluence of junctional nests, florid pagetoid spread and consumption of the epidermis, expansile dermal growth, nuclear pleomorphism, and hyperchromasia. In conclusion, we report only the second case of a Spitz nevus showing a striking rosette-like morphology. Awareness and recognition of this unusual pattern are important to avoid overdiagnosis as melanoma with all its associated implications.

Pilomatrixoma misdiagnosed as round cell tumor on fine-needle aspiration cytology

Sir, Pilomatrixoma or calcifying epithelioma of Malherbe is a benign appendageal tumor with differentiation toward hair cortex cells and accounts for almost 20% of pilar tumors. It usually occurs as a solitary lesion on the face or upper extremities and is composed of 2 types of cells: basaloid cells and shadow cells, present in irregularly shaped islands and separated by a cellular stroma.[1] There is a tendency for basaloid cells to be overrepresented in fine-needle aspiration (FNA) smears, probably because they are more easily detached by the needle. This often leads to an erroneous cytological diagnosis.[2] We report a case of pilomatrixoma, which was misdiagnosed on fine-needle aspiration cytology (FNAC) as round cell tumor. The patient was a 16-year-old male, who presented with a rapidly enlarging, painless 1.5 Χ 1 cm nodule in the right posterior cervical region for 2 months. A clinical impression of the posterior cervical lymphadenopathy was made and an FNA was requested. FNAC smears were cellular, showing cells with round to ovoid nuclei, 1-3 prominent nucleoli and scanty cytoplasm, dispersed singly as well as in clusters [Figure 1]. Rosette-like appearance was seen in an occasional cluster. Nuclear molding was also noted in some of them. Few foreign-body type giant cells were also encountered. A diagnosis of round cell tumor was made and excision biopsy was advised.Figure 1: Photomicrograph showing clusters of round, basaloid cells, some exhibiting nuclear molding, in the fine-needle aspiration smear.Histopathologic examination of the excised specimen showed the typical histology of pilomatrixoma [Figure 2].Figure 2: High-power view showing basaloid cells and ghost cells (HandE, ×400). The inset shows foreign body giant cell reaction (HandE, ×400).Pilomatrixoma may arise in persons of any age, but 60% occur in the first 2 decades of life.[1] It has been variably misinterpreted as round cell tumor,[3] squamous cell carcinoma,[4] or even as metastatic carcinoma.[4] The cytologic diagnosis is based on the combination of basaloid cells, ghost cells, and foreign-body giant cells against an inflammatory background. Basaloid cells can be seen as single cells, in clusters, sheets, or as bare nuclei in the background. Ghost cells are usually seen in clusters. The above-mentioned diagnostic triad may not necessarily be present in all cases, especially when the aspirate is from the periphery or from an early lesion. Smears that show mainly basaloid cells can be easily misinterpreted as small round cell tumor because of their high nucleus:cytoplasmic ratio, slight nuclear hyperchromasia, and presence of nucleoli. On the other end of the spectrum, when ghost cells and foreign body giant cells predominate, the cytologic features can even mimic epidermal inclusion cyst or giant cell lesions.[4] Rapidly growing, early lesions of pilomatrixoma, predominantly composed of basaloid cells may lead to a misdiagnosis as a metastatic deposit.[4] This possibility was also considered by us, but the age of the patient and lack of significant nuclear pleomorphism made us favor a diagnosis of round cell tumor. We were unable to find ghost cells even after careful retrospective analysis of the slides. However, lack of shadow cells does not preclude correct diagnosis in the presence of the other relevant cytologic features.[5] Appreciation of the 2 different cell types, along with correlation with the clinical presentation should help the cytopathologist to arrive at a correct diagnosis.

Perinatal Autopsy Findings in Three Cases of Jugular Lymphatic Obstruction Sequence and Cardiac Polyvalvular Dysplasia

Three infants with a prenatal diagnosis of Noonan's syndrome suffered fetal hydrops and immediate neonatal death. The infants all had the external appearance of jugular lymphatic obstruction sequence with wide-spaced nipples, redundant posterior nuchal skin, and edema of the dorsa of the feet and hands. All 3 demonstrated thick, redundant leaflets of all 4 cardiac valves, and 2 had a membranous ventricular septal defect. One female infant had a mutation of the PTPN11 gene. Two males had no common mutation of PTPN11. The males demonstrated other abnormalities in common, including small penis, testicular malformation, rosette-like appearance of the pituicytes, and an eosinophil infiltration of the pancreatic islets with islet cell hypertrophy. Detailed anatomy of cases of lymphatic obstruction sequence fetuses can be correlated with an increasing number of genetic mutations associated with Noonan's syndrome and related syndromes in mice and humans.

Manifestations auditives et vestibulaires isolées inaugurales d’angiomes caverneux du tronc cérébral: A propos de 3 observations

Cavernous haemangiomas (cavernomas)(CH) are relatively rare (2% of cranial tumoral pathology) vascular malformations mostly observed in the central nervous system. Their most common topographical site in brain stem is midline in the pons, for which clinical course may mimic symptoms of peripheral origin (sudden deafness, fluctuating hearing loss, Meniere-like vertigo).To establish the correlation between the clinical manifestations of hearing and balance disturbance and the anatomical site within the pons of cavernous haemangiomas, and to describe their clinical features, and the findings on auditory brainstem response (ABR) and magnetic resonance imaging (MRI). To propose a literature review about CH and its implications.We made a retrospective review of the histories of three patients aged 24, 44 and 45 years, diagnosed as having cavernomas of the brainstem in which audiometric evaluation, videonystagmography (VNG), ABR and imaging techniques lead to the diagnosis of intracranial cavernoma.The clinical and radiological files were reviewed and a direct relationship between symptoms and localization was found in all 3 patients, especially in relation to our understanding of the auditory and vestibular pathways within the brainstem.The literature regarding cavernomas of the pons is reviewed and the clinical, neuroimage, pathological, natural course and management aspects of the disease are discussed. We recommend the use of cerebral MRI for initial diagnosis which shows a typical rosette-like appearance with a heterogeneous signal on T2-weighted images, along with follow-up and investigation into similar profiles among family members. At present there is no consensus about the treatment to follow when cavernomas are located in the brain stem. There is no specific medical treatment for this condition, and surgery is indicated only exceptionally. Anticoagulant therapy, platelet-dispersing medication and violent sports activities are contraindicated.

Characterization of the cuticular surface wax pores and the waxy particles of the dustywing, Semidalis flinti (Neuroptera: Coniopterygidae)

The adult dustywing, Semidalis flinti Meinander (Neuroptera: Coniopterygidae), begins producing circular-shaped waxy particles after eclosion. The waxy material, which forms the particles, is extruded from individual pores found in clusters on the abdomen. Pores also are present in two rows of three pores on the frontalis and two pores on the first segment of each antennae. The pores have a rosette-like appearance and each pore extrudes dual waxy ribbons. As each ribbon extends a short distance out of the pore, it begins to curl back on itself until the end makes contact with the ribbon. The curled end then breaks free from the extruding ribbon to form the circular waxy particles with fluted edges approximately 2.75-μm diameter. The adults use the particles to cover all parts of their body except for their eyes and appear to lightly coat their antennae. The lipid portion of the particles consists largely of free fatty acids, almost exclusively the 24-carbon fatty acid, tetracosanoic acid. Minor lipid classes are hydrocarbons, fatty alcohols and unidentified material.

Fine structure of leopard frog (Rana pipiens) lymphocytes after in vitro transformation by phytohemagglutinin

Stimulation of leopard frog (Rana pipiens) spleen lymphocytes in vitro with phytohemagglutinin (PHA) caused a gradual change from small or medium sized lymphocytes to lymphoblasts. Lymphocytes cultured with PHA formed cell clusters with uropods oriented towards the center, giving them a rosette-like appearance. Mitotic figures were observed within lymphocyte clusters. At the ultrastructural level, unstimulated lymphocytes had sparse cytoplasm containing a few mitochondria, scattered free ribosomes and nuclei containing heavy clumps of heterochromatin. In contrast, after PHA stimulation, lymphocytes possessed the typical ultrastructure of lymphoblasts. The nucleus contained loosely packed euchromatin and prominent nucleoli. Ribosomes were aggregated to form polysomes, rough endoplasmic reticulum was sparse and mitochondria numerous. Uropods contained a well developed Golgi apparatus, centrioles with associated microtubules, various membrane bound bodies and abundant mitochondria and polysomes. The fine structural features of transformed frog lymphocytes are similar to those observed in several mammalian species, suggesting that this facet of lymphocyte biology has been conserved during evolution.

Demonstration of non-infectious hemagglutinating particles of rabies virus and isolation of the hemagglutinin by disruption of the virion with Nonidet P-40.

Non-infectious hemagglutinating particles of rabies virus accumulated in the fluid phase of chick embryo cell cultures at 6 days post-infection, though they were undetectable at 4 days. They were characterized as looped filaments resembling viral envelope as revealed by electron microscopy. Another form of hemagglutinin (HAnin) was obtained by solubilization of partially purified virions with Nonidet P-40 (NP-40) followed by successive high speed and CsCl density gradient centrifugations. The density of the isolated HAnin averaged 1.28 g/cm3. SDS-polyacrylamide gel electrophoresis of the HAnin demonstrated that it was mainly composed of a glycoprotein (G) with a molecular weight of 83,000. Electron microscopically, it differed from the above non-infectious hemagglutinating particles, being much smaller in size and showing a star- or rosette-like appearance with a diameter of about 25 nm, composed of a central particle surrounded by particles resembling envelope-spikes. Virus-neutralizing (VN) and hemagglutination inhibiting (HI) antibodies were produced in rabbits immunized with the HAnin isolated from virions.