Morphological and functional classification of the hemocytes of adult female Simulium vittatum (Diptera: Simuliidae).

Morphology and function of the hemocytes of 1-d-old, female Simulium vittatum Zetterstedt were studied using light and scanning electron microscopy. Four types of hemocytes, comparable with those of other medically important Diptera, were identified: prohemocytes, plasmatocytes, granulocytes, and spherulocytes. Plasmatocytes and granulocytes contained neutral red granules, but only granulocytes exhibited significant acid phosphatase activity. Plasmatocytes and granulocytes were identified as the primary phagocytes: plasmatocytes and granulocytes of bacteria in vitro and granulocytes of human red blood cells in vivo. Granulocytes also were observed attached to and degranulating into fat body and hemopoieticlike tissue fragments, perhaps assisting in the mobilization of nutrients for egg development and in the release of immature hemocytes into circulation.     

Characterization of phagocytic hemocytes in Ornithodoros moubata (Acari: Ixodidae)

Effects of fetal bovine serum (FBS) and complement on phagocytic activity in Ornithodaros moubata (Murray 1877) hemocytes and protease activity in the hemocytes were examined. At least three morphologically different cell types, granulocytes, plasmatocytes, and prohemocytes, were detected in hemolymph of O. moubata, and granulocytes and plasmatocytes showed phagocytic activity. FBS altered phagocytic activity of granulocytes, and complement affected phagocytic activity of plasmatocytes. Ticks were inoculated with fluorescent polystyrene beads in combination with FBS or complement. The average number of beads in granulocytes was significantly higher in the FBS injected group than the control (P < 0.01). The percentage of bead-ingesting plasmatocytes in complement inoculated ticks was significantly lower than that in heat-inactivated complement inoculated and control ticks (P < 0.05). Proteases of tick hemocytes localized in small granules in the cytoplasm not only in phagocytic hemocytes but also in prohemocytes. Results suggested modulation of tick hemocyte function through serum components, and digestion of phagocytosed foreign bodies in the hemocytes.     

Histochemical and ultrastructural features of an equine pulmonary granular cell tumour (myoblastoma)

Multiple nodules of a granular cell tumour (myoblastoma) in the right lung of a horse were characterized histologically by closely-packed polyhedral cells with abundant eosinophilic granular cytoplasm. Occasional cells contained angulate bodies, which have not been previously reported in equine granular cell tumours. The cytoplasmic granules and the angulate bodies were periodic acid/Schiff positive and diastase-resistant. Ultrastructurally, the tumour was composed of three cell types: granular cells, angulate body cells, and interstitial cells. Granular cells were the most numerous type. They contained small, round, cytoplasmic granules with vesicular or amorphous contents and large pleomorphic granules composed of segregated cytoplasmic constituents. Mature angulate body cells contained membrane-bound angulate bodies and cytoplasmic granules like those of the granular cells. Early angulate body cells, containing non-membrane-bound angulate bodies, resembled interstitial cells. Fusiform, fibroblast-like interstitial cells were the least differentiated cell. The ultrastructural appearance of this neoplasm supports the theory that granular cell tumours arise from a pluripotential mesenchymal cell.     

The role of hemolymph in the initial cellular attachment to foreign cells by the hemocytes of the silkworm,

The effects of silkworm hemolymph, , on the frequency of hemocyte-binding were studied using the scanning electron microscopy ( SEM ) and a rosette assay with goose erythrocytes ( GRBC ). Hemocytes from the last instar larvae were able to bind to GRBC int he absence of hemolymph. Hemocytes type involved in sponteneous cytoadherence was mainly the granular cell, while both plasmatocyte and prohemocyte were also observed to adhere to GRBC. However, the frequency of these two hemocytes binding to GRBC was low compared with that of granular cells. Observations with the SEM showed that the presence of hemolymph increased the number of GRBC-binding hemocytes, especially the granular cells and plasmatocytes. Therefore, hemolymph probably had a significant role in the attachment of granular cells and plasmatocytes to foreign erythrocytes.     

The role of hemolymph in the initial cellular attachment to foreign cells by the hemocytes of the silkworm, Bombyx mori

The effects of silkworm hemolymph, $\text{Bombyx mori}$, on the frequency of hemocyte-binding were studied using the scanning electron microscopy ( SEM ) and a rosette assay with goose erythrocytes ( GRBC ). Hemocytes from the last instar larvae were able to bind to GRBC $\text{in vitro}$ int he absence of hemolymph. Hemocytes type involved in sponteneous cytoadherence was mainly the granular cell, while both plasmatocyte and prohemocyte were also observed to adhere to GRBC. However, the frequency of these two hemocytes binding to GRBC was low compared with that of granular cells. Observations with the SEM showed that the presence of hemolymph increased the number of GRBC-binding hemocytes, especially the granular cells and plasmatocytes. Therefore, hemolymph probably had a significant role in the attachment of granular cells and plasmatocytes to foreign erythrocytes.     

Ultrastructural Pathology of Glial Brain Tumors Revisited: A Review

The ultrastructural pathology of primary brain tumors of glial origin is examined. These are divided into two major groups. The first category comprises astrocytoma with the variants: fibrillary, protoplasmic, gemistocytic, and anaplastic. These are biologically aggressive tumors of a relatively high proliferative potential and include a substantial proportion of cases that transform into the most malignant secondary glioblastoma. The second category, comprised of rather benign tumors of a limited proliferative capacity and a reasonable good prognosis, includes such clinico-pathological entities as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and subependymal giant cell astrocytoma of tuberous sclerosis. There is no ultrastructural feature, however, which makes it possible to discriminate between major subclasses of astrocytes; but secondary glioblastoma cells, while still retaining the stigmata of neoplastic astrocytes, are characterized by nuclei that seem to be more indented, cisterns of the endoplastic reticulum may be distended, and intranuclear pseudoinclusions are frequently observed. Primary glioblastoma, which probably originates de novo, is characterized by poorly differentiated cells with a paucity of subcellular organelles and no obvious features of astrocytic origin. Granular cell tumor also belongs to neoplasms of astrocytic lineage and the hallmark of this entity is a cell characterized by the presence of numerous membrane-bound, electron-dense autophagic vacuoles. Its malignant analogue is the granular cell glioblastoma. Two subtypes of granular cell glioblastoma have been distinguished. The first is characterized by the presence of numerous granular, electron-dense bodies which correspond to autophagic vacuoles. The second type is characterized by numerous electron-dense, amorphous masses within cellular processes. These electron-dense inclusions are virtually indistinguishable from minute Rosenthal fibers. The pilocytic astrocytoma is virtually indistinguishable at the ultrastructural level from fibrillary astrocytomas but cells tend to be more elongated. Besides Rosenthal fibers, two types of distinctive structures are relatively common in pilocytic astrocytomas: eosinophilic hyaline droplets and round granular bodies, which are composed of large aggregates of electron-dense secondary lysosomes or small electron-dense bodies, respectively. Pleomorphic xanthoastrocytoma is characterized by astrocytes surrounded by basal membranes. It belongs to a peculiar category of astrocytic “desmoplastic” brain tumors occurring in younger patients, the common denominator for which is the presence of basal lamina. The last category in this group is subependymal giant cell astrocytoma, a tumor of bivalent (glial and neuronal) differentiation, the cells of which are characterized by the presence of peculiar crystalloids. The hallmark of oligodendroglioma is the presence of concentric arrays of membranes (so-called membrane laminations, whorls, or scrolls). A fragment of the cytoplasm sequestrated within a particular whorl may contain mitochondria, lysosomes, or abundant glycogen granules. Ependymomas are characterized by a florid picture dominated by the presence of microlumina, cilia with basal bodies (blepharoplasts), microvilli, and long, interdigitating intercellular junctions of the zonulae adherentiae type. Ganglioglioma, the last category covered by this review, is a mixed glio-neuronal tumor. While glial cells are indistinguishable from their counterparts encountered elsewhere (mostly pilocytic astrocytes), the ganglion cells are characterized by abundant intracytoplasmic dense-core vesicles, absence of intermediate filaments, and numerous microtubules. Occasionally a close apposition of ganglion cells and Rosenthal fibers is seen. Dense-core vesicles are pleomorphic and ranged in a diameter from small synaptic vesicles to large lysosome-like neurosecretory granules.     

Ultrastructural juxtaglomerular cell changes in normotensive rats treated with quinapril, an inhibitor of angiotensin-converting enzyme

Sequential histologic and ultrastructural changes in juxtaglomerular apparatus (JGA) were defined in male rats treated with quinapril, an inhibitor of angiotensin-converting enzyme (ACE). Doses of 0, 10, 100, and 400 mg/kg were administered daily by gavage for up to 4 weeks. Granular juxtaglomerular (JG) cells were normal or hypogranular on Day 1 at all doses and were hypergranular by Day 7 in rats given 100 and 400 mg/kg relative to age-matched controls. Histologically, JGA hypertrophy was apparent by Day 7 at all doses and was most pronounced by Day 14 in intermediate and deep cortical zones of rats given 100 and 400 mg/kg. Ultrastructurally, hypertrophic JG cells had abundant rough endoplasmic reticulum and free ribosomes, and prominent Golgi complexes associated with numerous cytoplasmic coated vesicles. Dose-dependent increases in numbers of protogranules, altered granules, and cytoplasmic vacuoles occurred in association with decreased size and increased pleomorphism of mature secretory granules. Granule alterations included vesicular to lamellar membranous matrical inclusions, irregular patterns of osmiophilia, matrical vacuolation, and flocculent to coarsely granular matrix of greater density than mature granules. We concluded that JG cell hypertrophy and hyperplasia occurred rapidly in response to subchronic ACE inhibition. Further, ultrastructural changes in JG cells were indicative of stimulated renin synthesis by a regulated pathway, renin secretion by exocytosis and cytoplasmic solubilization of granules, and autophagy of granules as a mechanism whereby JG cells regulate levels of stored renin under conditions of excessive stimulation.     

Heterogeneity of the MtTW15 mammosomatotropic tumor. II. Characterization of parenchymal cells by superimposition immunocytochemistry and electron microscopy

Large MtTW₁₅ tumors, which secrete growth hormone (GH) and prolactin (PRL), are composed of ovoid, elongated, and angular cells which demonstrated interdigitating processes and junctional complexes. The majority of the cells were essentially agranular, but two types of granulated cells were identifiable. One class of granulated cells contained moderate to sparse populations of round dense-cored granules measuring up to 250 nm in diameter. Rod-shaped to filamentous mitochondria with an electron-dense matrix were characteristic of a second class of granulated cells with pleomorphic granules of various sizes and electron densities. Images of exocytotic release of the round dense-cored granules were frequently seen, but were not observed with the pleomorphic granules, many of which were judged to be lysosomes. Superimposition immunocytochemistry revealed hormones only in the granulated cells with round to ovoid granules. Morphometry indicated that hormone specific subpopulations of tumor cells can be identified since PRL secretory granules were significantly smaller than GH secretory granules (149 ± 6 nm for PRL versus 221 ± 9 nm for GH, P < 0.001). The vast majority of immunopositive cells contained only GH or PRL, but a few were observed containing both hormones. Ovoid to irregular-shaped nuclei, large lipid inclusions, numerous free ribosomes and polyribosomes, moderate development of the rough endoplasmic reticulum, and prominent Golgi profiles were characteristics of all cell types. Irrespective of the presence or absence of cytoplasmic granular elements, particles resembling viruses were encountered in many tumor cells, and these frequently appeared to be budding into the cisternae of the endoplasmic reticulum.     

The fine structure of the chinchilla placenta

The structure of the placental labyrinth, interlobular or “coarse” syncytium, visceral (splanchnopleuric) yolk sac, giant cells and subplacenta of the chinchilla was studied with the electron microscope. The fine structure of the interhemal membrane of the placental labyrinth was found to be hemomonochorial, consisting of a single layer of syncytial trophoblast. In this respect, the placental labyrinth was similar to that of another caviomorph rodent, the guinea pig. The labyrinthine trophoblast had pinocytotic vesicles as well as larger vacuoles and multivesicular bodies. The interlobular syncytium contained granular endoplasmic reticulum, and in one case from early in gestation there were intracisternal granules in the ER. The visceral endodermal cells of the inverted yolk sac placenta had a well-developed system of apical vesicles and tubules as well as larger cytoplasmic vacuoles. Their appearance was similar to that of endodermal cells found in other rodents which are known to absorb proteins and other substances from the uterine lumen. Towards term the giant cells were often vacuolated and contained large deposits of glycogen as well as lipid droplets. The syncytial trophoblast of the subplacenta contained numerous moderately electron-dense granules which may be secretory in function; cytotrophoblastic cells lacked these granules. The subplacental syncytium often surrounded spaces or lacunae which contained an electron-dense granular material.     

Induction of immunity by latex beads and by hemolymph transfer in Galleria mellonella.

Injection of sterile latex beads into the hemocoel of last instar larvae of Galleria mellonella provoked a strong defense reaction. Cellular defense by hemocytes was followed by enhanced antibacterial activity in hemolymph. Latex-injected insects showed increased survival rates after a challenge injection with high doses of bacteria. Factors which stimulate the production of antibacterial activity could be demonstrated soon after injection by transfer of hemolymph from preinjected to untreated larvae. A large induction capacity in donor hemolymph was accompanied by a strong decrease in the total hemocyte count of free floating hemocytes, resulting from a decrease in number of plasmatocytes and granular cells, the cell types involved in the cellular defense against the injected latex beads. The results presented support the hypothesis that during cellular defense reactions, factors are released from the hemocytes which stimulate the production of antibacterial substances.     

Characterization of the circulating hemocytes in mud crab (Scylla olivacea) revealed phenoloxidase activity

This study focused on an isolation and characterization of the circulating hemocytes in mud crab, Scylla olivacea. Isolation of specific cell types of hemocytes from crab hemolymph was accomplished by using 60% Percoll density gradient centrifugation. Four separated bands of the hemocytes were successfully obtained. Characterization of these isolated hemocytes by light microscope using trypan blue-rose bengal staining, rose bengal–hematoxilin staining, and phase contrast revealed four distinct types of hemocyte cells. Using their specific morphology and granularity, they were identified as hyaline cell (HC), small granular cell (SGC), large granular cell (LGC) and mixed granular cell (MGC). Transmission electron microscopy (TEM) revealed more details on specific cell size, size of cytoplasmic granule, and nuclear to cytoplasmic ratio, and confirmed the classification. Relative abundance of these cells types in the hemolymph of an adult crab were 15.50 ± 8.22% for HC, 55.50 ± 7.15% for SGC, 13.50 ± 5.28% for LGC, and 15.50 ± 3.50% for MGC. Proteomic analysis of protein expression for each specific cell types by two-dimensional electrophoresis identified two highly abundant proteins, prophenoloxidase (ProPO) and peroxinectin in LGC. Determination of phenoloxidase (PO) activity in each isolated cell types using in vitro and in situ chemical assays confirmed the presence of PO activity only in LGC. Based on an increased PO activity of crab hemolymph during the course of White Spot Syndrome Virus (WSSV) infection, these results suggest that prophenoloxidase pathway was employed for host defense mechanism against WSSV and it may link to the role of large granular hemocyte.     

Functional differentiation of spider hemocytes by light and transmission electron microscopy,and MALDI-MS-imaging

The most abundant cell types in the hemolymph of Cupiennius salei are plasmatocytes (70–80%) and granulocytes (20–30%). Both cells differ in shape, cytochemical and transmission electron microscopy staining of their cytoplasma and granules. According to MALDI-IMS (matrix-assisted laser desorption ionisation-mass spectrometry imaging), granulocytes exhibit ctenidin 1 (9510 Da) and ctenidin 3 (9568 Da), SIBD-1 (8675 Da), and unknown peptides with masses of 2207 and 6239 Da. Plasmatocytes exhibit mainly a mass of 6908 Da. Unknown peptides with masses of 1546 and 1960 Da were detected in plasmatocytes and granulocytes. Transmission electron microscopy confirms the presence of two compounds in one granule and cytochemical staining (light microscopy) tends to support this view. Two further hemocyte types (cyanocytes containing hemocyanin and prehemocytes as stem cells) are only rarely detected in the hemolymph. These four hemocyte types constitute the cellular part of the spider immune system and this is discussed in view of arachnid hemocyte evolution.     

Lipid-rich carcinoid tumor of the thymus gland: diagnosis by fine-needle aspiration biopsy

In this report we describe the cytologic features of an unusual thymic carcinoid tumor containing prominent cytoplasmic lipid vacuoles that was diagnosed by fine-needle aspiration biopsy. The tumor presented as a presternal subcutaneous mass in an 81-yr-old female, with a contiguous mediastinal mass on computed tomography. The cytomorphologic features included numerous discohesive cells with eccentric, round to oval nuclei, granular chromatin, and scant cytoplasm containing numerous intracytoplasmic, clear vacuoles. The neoplastic cells were reactive for neuroendocrine markers by immunocytochemistry and showed reactivity of the intracytoplasmic vacuoles with an oil red-O stain for neutral lipid. Ultrastructural examination confirmed the presence of intracytoplasmic lipid vacuoles and neurosecretory granules. Subsequent surgical excision confirmed the diagnosis. We believe this to be the first report describing these features in a primary thymic carcinoid tumor. The differential diagnosis of mediastinal tumors with clear-cell features and cytoplasmic vacuolization is also discussed.     

Fine‐needle aspiration cytomorphology of sebaceous lymphadenoma of the salivary gland

Sebaceous lymphadenoma (SLA) is a histologic variant of lymphadenoma or sebaceous adenoma of the salivary gland. The fine‐needle aspiration (FNA) cytology of SLA has not been well‐described. In this report, we reported a case that involved an 81‐year‐old male with a long‐standing left parotid mass and was diagnosed on FNA cytology. The FNA smears showed clusters of three types of epithelial cells in a background of abundant lymphoid cells, macrophages and abundant proteinaceous materials. The predominant epithelial cells were large polygonal cells with abundant cytoplasm filled with multiple, uniform, small, and clear vacuoles, ill‐defined cytoplasmic borders, and small centrally located round nuclei with finely granular chromatin, conspicuous nucleoli and indented nuclear membranes apparently imprinted by cytoplasmic vacuoles. These cells were surrounded by polygonal or flat cells with less or more dense cytoplasm, indistinct cell borders and round or oval small nuclei with smooth nuclear membranes, which correspond to germinative or basaloid cells. Some cells had granular cytoplasm. Large three dimensional clusters of nonkeratinized squamous cells have oval nuclei containing evenly distributed chromatin, and scant to moderate dense cytoplasm that were arranged in a “stream of fish” pattern. Rare granulomas and cystic contents (degenerated cells, inflammatory cells, macrophages, and abundant granular debris/proteinaceous material) were also seen. The diagnosis of SLA was confirmed by the surgical resection. Diagn. Cytopathol. 2014;42:959–963. © 2013 Wiley Periodicals, Inc.     

免疫组化电镜示垂体LH细胞

应用免疫组化电镜显示垂体黄体生成素(LH)细胞的形态特徵、超微结构以及反应阳性颗粒的分布状况等,并按此将LH细胞分为四型。一、二型细胞内大小分泌粒均含有LH;三型细胞长(?)的150 nm及200 nm颗粒显免疫反应阳性,且部分胞膜和微绒毛顶部界膜内外附着致密细粒;四型细胞出现反应阴性颗粒,仅在rER膜囊外显有直径30～40 nm黑色细粒。LH细胞的分泌可能以外排、分子渗透和局部分泌三种方式排出LH。     

Ultrastructure of the corpus luteum of the white-tailed deer during pregnancy

The fine structure of corpora lutea from 14 white-tailed deer was studied from early through near-term pregnancy. The corpora contained both thecal and granulosal lutein cells. The small, elongate and cylindrical thecal lutein cells contained many lipid droplets, juxtanuclear Golgi elements, abundant agranular endoplasmic reticulum, and other cytoplasmic organelles. These cells were observed throughout pregnancy. Some of the thecal lutein cells became modified during early to midpregnancy. The modified thecal lutein cells possessed many lipid droplets, several lysosomes, packets of PAS-positive glycogen granules, and numerous small membranous whorls of agranular endoplasmic reticulum. The granulosal lutein cells had highly folded and/or ruffled plasma membranes, abundant tortuous tubular and cisternal agranular endoplasmic reticulum, numerous rod-shaped to round mitochondria with tubular and lamellar cristae, Golgi elements, and a few packets of granular endoplasmic reticulum. Many granulosal lutein cells became modified during mid- to near-term pregnancy by the addition of numerous small membrane-bound osmiophilic droplets and variable numbers of large nonmembrane-bound lipid droplets. The granulosal and thecal lutein cells appeared more active in steroid biosynthesis than the modified granulosal and thecal lutein cells.     

Cellular-mediated reactions to foreign organisms inoculated into the hemocoel of Anopheles albimanus (Diptera: Culicidae)

The immune response against different organisms and particles inoculated in the hemocoel of female Anopheles albimanus Wiedemann was investigated. Histological and ultrastructural observations indicated that melanization and hemocyte type participation varied according to the particles inoculated. The initial responses against heat-killed Microccocus lysodeikticus and Escherichia coli included hemocyte lysis and melanization whereas the response to heat-killed Saccharomyces cerevisiae was only cellular, and an initial melanization of Sephadex G-25 (neutral charged) beads was followed by the formation of cellular aggregates. After 24 h, hemocytes were involved in all terminal encapsulation events. Plasmodium vivax Grassi and Feletti formalin-fixed sporozoites induced a weak response. Cellular aggregates were observed 1 h postinoculation, but participating hemocytes could not be identified because of the extensive cellular damage and lysis. Sporozoites were also observed in the core of these aggregates, mixed with cell debris and free in the hemolymph. The effect on the inoculated particles was also different-S. cerevisiae was encapsulated only by hemocytes, whereas M. lysodeikticus was lysed and E. coli was phagocytosed by plasmatocytes. These results indicate that hemocytes are important components in the immune response in An. albimanus.     

Neuroglian-positive plasmatocytes of Manduca sexta and the initiation of hemocyte attachment to foreign surfaces

Observations of hemocyte aggregation on abiotic surfaces suggested that certain plasmatocytes from larvae of Manduca sexta act as foci for hemocyte aggregation. To establish how these particular plasmatocytes form initial attachments to foreign surfaces, they were cultured separately from other selected populations of hemocytes. While all circulating plasmatocytes immunolabel with anti-beta-integrin monoclonal antibody (MAb), only these larger plasmatocytes immunolabel with a MAb to the adhesion protein neuroglian. Neuroglian-negative plasmatocytes and granular cells that have been magnetically segregated from the majority of granular cells adhere to each other but fail to adhere to foreign substrata; by contrast, neuroglian-positive plasmatocytes that segregate with most granular cells adhere firmly to a substratum. Hemocytes form stable aggregates around the large, neuroglian-positive plasmatocytes. However, if neuroglian-positive plasmatocytes are separated from most granular cells, attachment of these plasmatocytes to foreign surfaces is suppressed.     

The Cytology of a Thyroid Granular Cell Tumor

Granular cell tumor (GCT) of the thyroid is rare. Before this report, only four cases of thyroid GCT have been reported, none of which presented a cytopathological examination. In this paper, we report the fine needle aspiration cytology and pathological analysis of a thyroid GCT from a 12-year-old girl who presented with a painless neck mass. The tumor cells were single, in syncytial clusters, or pseudofollicles, contained small round, oval, or spindle nuclei, indistinct nucleoli, and a large amount of grayish, granular fragile cytoplasm. The background contained granular debris and naked nuclei. A differential diagnosis of thyroid GCT with more frequent thyroid lesions containing cytoplasmic granules, including Hurthle cells, macrophages, follicular cells, and cells of black thyroid syndrome, was also performed.     

On the fine structure of the Mehlis gland cells in the liver fluke,Fasciola hepatica L.

Summary The cells of Mehlis's gland in the liver fluke (Fasciola hepatica L.) have been studied with light and electron microscopy. The gland contained large cells in the periphery and small cells in the centre. The large cells presented morphological features characteristic of secretory cells, viz. large nucleoli, cytoplasmic basophilia, a well developed endoplasmic reticulum, abundant ribosomes, and secretory granules in different stages of development. The mitochondria were moderately frequent. Several small groups of vesicles and membraneous lamellae reminiscent of Golgi complexes occurred randomly in the cytoplasm. These structures were associated with mitochondria and secretory granules. Evidence of alterations and conversion into a cell débris was observed, and a process of holocrine secretion was suggested.The small cells were strongly basophilic, contained numerous ribosomes and mitochondria, and a few dense bodies. The internal membranes were few. The small cells had a primitive appearance and showed no secretory properties.With 7 Figures in the TextSupported by a grant from the Swedish Agricultural Research Council.