Dynamic features of luteal secretory granules: ultrastructural changes during the course of pregnancy in the cow

The ultrastructure of large and small cells from corpora lutea of pregnant cows (days 45-280) were evaluated by electron microscopy. The distinguishing features of small cells (10-15 micron in diameter) included stacks of rough endoplasmic reticulum, whorls of smooth endoplasmic reticulum, elongated mitochondria containing crystalline-like inclusions, and cytoplasmic lipid droplets. The large cells (20-50 micron in diameter) contained numerous mitochondria packed tightly together (no elongated structures), an abundance of smooth endoplasmic reticulum (no whorls), and a large number of membrane-bound secretory granules (150-300 nm in diameter). These granules appeared to be packaged in the Golgi, accumulated at a paranuclear region, and migrated as a group to the cell membrane where they were exocytosed. These granules were first observed on day 45 and increased in number to reach a peak around day 200. Lipid droplets became a common cytoplasmic inclusion in the large cells during the third trimester of pregnancy. In addition, during this stage, an electron-dense substance began to accumulate in the mitochondria to such an extent as to occlude the cristae. These mitochondria looked like large (500-1800 nm) membrane-bound granules; however, they did not undergo exocytosis. Their appearance in large cells during the last 3 months of pregnancy may reflect a change in steroid metabolism. Thus, there are two morphologically distinct cell types throughout pregnancy in the cow. The large cell containing the secretory granules underwent what appeared to be a progressive state of apparent deterioration with advancing pregnancy. The morphology of the small cell did not undergo such a dynamic change. No morphological evidence was observed that would support a transition state between the two cell types.     

Ultrastructural identification of substance P cells and their processes in rat sensory ganglia and their terminals in the spinal cord by immunocytochemistry

The unlabeled substance P (SP) antibody-peroxidase-antiperoxidase reaction was used on tissue prior to embedding in epoxy reins for ultrastructural identification of the SP cell and its immunoreactive granules. The SP cell is 10-20 mum in diameter and has sparse cytoplasm with numerous intensely reactive SP granules 100-300 nm across, large clear vacuoles, elaborate smooth endoplasmic reticulum, fragmentary rough endoplasmic reticulum, dispersed ribosomes, few mitochondria, and a modest Glogi apparatus. The large SP-reactive granules are discharged into the extracellular space, either with cell membrane intact or as unbound dense material. The membrane-bound dense granucles are transported intact through endothelial cells into the blood or are picked up by Schwann cells and fibroblasts. Other SP-reactive granules lose their limiting membranes, fragment, and then disperse into fine immunoreactive grains that bind to the extracellular matrix and to collagen. Dispersed SP-reactive granules are transported within myriad pinocytotic vesicles across endothelial cells with numerous luminal plications and are discharged into the blood. Pinocytosis of dispersed SP-reactive material, that can be detected intracellularly, also occurs in Schwann cells and fibroblasts. The SP axons to the substantia gleatinosa are unmyelinated or finely myelinated. Their synaptic varicosities display a generalized axoplasmic immunoreactivity, which also occurs in and around small vesicles. The larger SP synaptic vesicles are intensely reactive.     

Hypereosinophilic syndrome human eosinophil degranulation induced by soluble and particulate stimuli

Eosinophil degranulation induced by the calcium ionophore A23187 and opsonized zymosan particles was examined ultrastructurally in peripheral blood cells obtained from patients with the hypereosinophilic syndrome. Unstimulated hypereosinophilic syndrome eosinophils contained altered, vacuolated cytoplasmic granules and large cytoplasmic crystalloid structures not seen in normal cells. By morphometric analysis of transmission electron micrographs, the hypereosinophilic syndrome eosinophils contained a larger percentage of smaller sized cytoplasmic granules than normal cells. The hypereosinophilic syndrome eosinophils, however, were capable of undergoing noncytotoxic degranulation after stimulation with either A23187 or opsonized zymosan. Hypereosinophilic syndrome eosinophil degranulation was characterized by fusion of the perigranular membranes of adjacent cytoplasmic granules and vesiculation of the fused granules. Granule contents were released intracellularly into vacuoles after ionophore stimulation and into phagosomes containing the ingested zymosan particles. Noncytotoxic extracellular release of eosinophil peroxidase (EPO) was also observed after cell stimulation by either A23187 or zymosan. The capacity of hypereosinophilic syndrome eosinophils to degranulate after appropriate stimulation with release of toxic granule constituents such as EPO and other basic proteins may be important in the tissue injury observed in this syndrome.     

Neural tissue within anterior pituitary tumors generated by oncogene expression in transgenic mice.

Pituitary tumorigenesis occurs in a transgenic line of mice, alpha-T7, which carries a hybrid transgene composed of the 5' flanking region of the human glycoprotein hormone alpha-subunit gene (1.8 kb) linked to the coding region of the SV40 T-antigen gene (alpha-Tag). Tumor foci were identified within the anterior pituitary of both male and female transgenic mice. In addition to a parenchyma with hypertrophied endocrine cells, mostly of the gonadotrope lineage, we here report the unexpected presence of neural tissue within the anterior pituitary, either as foci as large as 1.0 mm in diameter or greater, or in delicate bundles ramifying amongst the granulated parenchymal cells. Areas richest in neural tissue frequently were associated with tumor tissue composed of giant cells of three varieties, all with electron-lucent cytoplasm and similar organellar distribution including small secretory granules (80-160 nm diameter). In type I cells, the secretory granules were aligned at the plasma membrane; in type II cells, the secretory granules were distributed throughout the cytoplasm; type III cells formed colloid-filled follicles and their secretory granules rarely exceeded 100 nm diameter. These giant cells frequently had bizarre pleomorphic nuclei intensely immunopositive for T-antigen and cytoplasm which was lightly immunopositive for alpha-subunit, and immunopositive either for the LH-beta or TSH-beta subunits. Neural tissue contacted the normal granulated parenchymal cells directly, i.e., without a basal lamina or any connective tissue intervening, but only rarely formed synaptoid junctions with these granulated cells. Synaptoid junctions containing round, smooth vesicles, as well as dense core vesicles, were numerous between the neural processes themselves and between the neural tissue and the giant cells of the tumor tissue. These data suggest that in alpha-T7 transgenic mice the giant cells represent highly transformed gonadotropes or thyrotropes, and that a neurotrophic factor may be expressed by these transformed pituitary parenchymal cells.     

Comparative study on the endocrine cells in the pancreas of Mauremys caspica (chelonia) in summer and winter

Four endocrine cell types were identified using peroxidase-antiperoxidase (PAP) technique and ultrastructurally characterized in the pancreas of Mauremys caspica in both winter and summer. In winter, insulin-immunoreactive cells were more abundant and the cell groups larger in the splenic than in the duodenal region, whereas in summer, medium or small cell groups were evenly distributed. Glucagon- and somatostatin-immunoreactive cells were found throughout the gland; they were more numerous in the splenic than in the duodenal region. Polypeptide pancreatic (PP)-immunoreactive cells were found only in the duodenal region. Somatostatin-immunoreactive cells were mainly isolated in winter and grouped in summer. Glucagon- and PP-immunoreactive cells had a similar arrangement in both seasons. Somatostatin- and PP-containing cells showed cytoplasmic processes and could be found next to the pancreatic ducts; the latter were also observed near insulin-immunoreactive cells. Some large secretory granules and numerous, isolated and long rough endoplasmic reticulum (RER) cisternae were seen in winter B cells; in summer B cells numerous lysosomes and few, dilated RER cisternae were found. Summer A cells showed well-developed, dilated RER cisternae and numerous vacuoles; secretory granules were more numerous in winter A cells. In winter B cells and summer A cells some nuclear filamentous inclusions were observed. Few RER cisternae were observed in winter D cells and many in summer D cells; secretory granules were found, the shape and electron density of which differed with the season. PP cells were characterized by their small secretory granules, which were less numerous in winter than in summer, being clustered at the cell pole or dispersed in the cytoplasm, respectively; in winter, the well-developed RER cisternae were dilated and irregularly distributed.     

Morphological and biochemical characterization of small and large bovine luteal cells during pregnancy

Small (15–18 μm) and large (18–45 μm) luteal cells were obtained from bovine corpora lutea of pregnancy by centrifugal elutriation of enzymatically dispersed luteal cells. Small luteal cells accounted for about 85% and large luteal cells for 8–12% of total luteal cell population.Small luteal cells were characterized by a low cytoplasmic/nuclear ratio with cytoplasm containing mitochondria, lysosomes, lipid droplets, dense granules and endoplasmic reticulum. Large luteal cells possessed a higher cytoplasmic/nuclear ratio with cytoplasm containing more abundant mitochondria, lipid droplets, dense granules and lysosomes compared to small luteal cells. Some of the mitochondria were very long. Both small and large luteal cells contained scarce amounts of Golgi elements. Dense granules were found close to the nucleus in both cell types. The nucleus of both cell types was acentric, irregular in shape and contained a well-defined nucleolus. The highly condensed chromatin in small luteal cells was found at the nuclear periphery and in the central region. Dispersed chromatin was found throughout the nucleus with condensed chromatin at the nuclear periphery of large luteal cells. Macrophages and fibroblasts were occasionally found in small luteal cell preparations, but their morphology was quite distinct from both small and large luteal cells. Scanning electron microscopy revealed that the majority of the small and large luteal cells were spherical or slightly elongated in shape. Small luteal cells displayed the presence of blebs, ruffles and short microvilli. Large luteal cell surface contained ruffles and randomly distributed clusters of blebs of different sizes, predominantly spherical in shape with a smooth surface. Finger-like projections were also occasionally seen.Small luteal cells contained significantly lower amounts of protein, but the ratios between protein and DNA were similar in both cell types. The basal, human chorionic gonadotropin (hCG)- or cyclic AMP-st′imulated progesterone production, the apparent dissociation constants for [¹²⁵I]hCG binding and the apparent total number of available sites per cell were similar in small and large luteal cells. The activities of enzymes that are involved directly or indirectly in progesterone biosynthesis and those involved in general cellular metabolism and biosynthesis were also similar in small and large luteal cells with one exception. That is, the activities of 5′-nucleotidase and NADH cytochrome c reductase were significantly higher in small compared to large luteal cells.     

Cytoplasmic bodies in lymphatic endothelial cell

Although micropinocytotic vesicles and other large vesicular structures have been observed in lymphatic endothelial cells on electron microscopy, in this study ultrastructure attention was focused on a variety of other membrane-bounded structures in the cytoplasm of these cells in the rabbit heart. The first type was oval or round in transverse section and elongated in longitudinal section, was 100-200 nm in diameter and contained regularly spaced tubules. These features resembled rod-shaped bodies detected thus far only in blood vascular endothelial cells. A second type of cytoplasmic body was also frequently seen in lymphatic endothelium. It contained irregularly spaced small vesicles, 5-7 in number and 45 nm in diameter. A third type of vesiculated body was only occasionally found. This latter structure was greater than the previously described bodies and ranged from 3-5 micron in diameter, and filled with granular, inhomogeneous material and filamentous-like components. The functional significance of these intraendothelial bodies is as yet unexplained.     

间日疟原虫红细胞内期电镜观察

间日疟原虫裂殖子钻入红细胞后,早期环状体呈哑铃形,其纳虫空泡内膜状物质通过红细胞中狭窄通道排出。滋养体形状不规则,或呈卵圆形,由单层表膜包绕,细胞质内具有无嵴线粒体,纳虫空泡中有电子致密颗粒。配子体形状规则,几乎充满被寄生的红细胞,由两层表膜包绕,细胞质内具有有嵴线粒体。雌配子体细胞质内核糖体、嗜锇小体和线粒体都比雄配子体丰富。被寄生的红细胞的3个主要变化为出现小泡、细胞质裂隙和凹窝小泡复合物。后者沿红细胞表膜分布,可能是薛氏小点。     

Ultrastructural characterization of human corticotrophs (ACTH cells)

Ultrastructural characterization of human corticotrophs (ACTH cells) was performed by 'superimposition technique', which enabled detailed ultrastructural observation of immunoreactive ACTH cells in adjacent semi-thin light microscopic immunoperoxidase and routine electron microscopic sections. The human corticotrophs were large and round or polygonal and were not stellate. They had scanty rough endoplasmic membranes and were packed with numerous large secretory granules measuring from 250 to 500 nm in diameter. The sizes of secretory granules in 6 human pituitaries were 448 +/- 128, 344 +/- 86, 448 +/- 117, 244 +/- 65, 316 +/- 76, and 340 +/- 93 nm, respectively. The granules were not seen in a single row along the plasma membrane as is the case in the rat. They possessed somewhat irregular outlines with a rarely discernible halo. Different densities of granule matrices were occasionally found. The cells often contained a few large heterogeneous vacuoles. From these findings, the human ACTH cells were recognized to be remarkably different in cell shape and size, properties of secretory granules and cytoplamic inclusions from those of the rat pituitary gland. In respect to secretory granule properties, the human ACTH cells are similar to those of some other mammals (fox, young pig, and lerot). More data is required to elucidate the relationship between human ACTH cell morphology and functional state.     

Electron microscopic observations of the rat endometrium during the implantation period, with special reference to its sex steroid hormone regulation (author's transl)]

Ultrastructural changes in the rat endometrium under several conditions including experiments of the inhibition of implantation were studied to clarify the sequential changes of the endometrium and their endocrinologic background during ovoimplantation. The following pertinent findings were noted. 1) Normal pregnancy. In the luminal surfaces, the microvilli were short and arranged rather irregularly and lost their so-called glycocalyx on L3. The large fungus-like protrusions appeared on L4. On L5, the luminal surfaces were completely covered with small serrated cytoplasmic protrusions. They formed the interdigitation btween the apposed surfaces and the uterine lumen was disappeared when the uterus was fixed in situ by the arterial perfusion method. High ATP-ase activity was demonstrated at the site of interdigitation. In the apical cytoplasm, many apical vesicles, well developed Golgi apparatuses, and dilated cisternae of the granular endoplasmic reticulum were observed on L3. On L5, however, these apical vesicles decreased in number and the Golgi apparatuses were small. On the contrary, the semilunar and coated vesicles were numerous, and the lysosomes increased both in number and size. Acid phosphatase activity was detected in these lysosomes. In the glandular epithelium, progressive increase in the number of small granules and the amount of amorphous substance were observed in the glandular lumen from L2, to L4. But on L4, some autophagosomes had already appeared in the cytoplasm. Swollen and degenerated mitochondria as well as many vacuoles were recognized on L5. In the stromal cells, the cytoplasm was enlarged, and contained many polyribosomes, granular endoplasmic reticulum with markedly dilated cisternae, lysosomes and lipid droplets on L5. The cytoplasmic protrusions on L5 were elongated and showed various features; one of them was situated very closely to the basement lamina of the luminal epithelium, and the other surrounded the lumen. Some of these protrusions were connected with the desmosomes. High ATP-ase activity was localized in these cytoplasmic protrusions, on the surfaces of the stromal cells, and in the stroma itself. 2) Delayed implantation and estrogenic transformation. In delayed implantation, the luminal surfaces were covered with regular microvilli and several fungus-like cytoplasmic protrusions. The cytoplasm contained many apical vesicles and large Golgi apparatuses that were observed both on L3 and L4 in normal pregnancy. At 48 hrs after the injection of estrogen, the interdigitation between the apposed luminal surfaces was also established. In the glandular epithelium, a slight enlargement of the glandular lumen and the appearance of small granules similar to those observed in normal pregnancy were noted at the 4th hr of estrogen treatment. In the stromal cells, two cells apposed each other very closely at the 4th hr and formed large cell masses at the 48th hr of estrogen treatment...     

A case of leukemic mastocytoma terminating in metamorphosis

A case of leukemic mastocytoma terminating in metamorphosis is reported. Three types of mastocytoma cells appeared in the peripheral blood and bone marrow, each differing in cytochemical staining and maturation ability in both in vitro and in vivo cultures. Most immature mastocytoma cells, which contained no granules and were lymphoblast-like cells, differentiated to have basophilic and metachromatically positive granules in the cytoplasm after culture in the diffusion chamber, resembling more mature cells (type II). Mature cells (type II), which had diffusely dispersed and metachromatically positive granules in the cytoplasm, came to have vacuoles with basophilic substances after culture in vitro, resembling most mature cells (type I) which contained large and clumped granules with metachromasia. These findings together with clinical findings and results of morphological studies suggest that most immature cells originate from second mature or most mature cells and effect a blastic transformation.     

Internal cell manipulation using infrared laser traps.

The ability of infrared laser traps to apply controlled forces inside of living cells is utilized in a study of the mechanical properties of the cytoplasm of plant cells. It was discovered that infrared traps are capable of plucking out long filaments of cytoplasm inside cells. These filaments exhibit the viscoelastic properties of plastic flow, necking, stress relaxation, and set, thus providing a unique way to probe the local rheological properties of essentially unperturbed living cells. A form of internal cell surgery was devised that is capable of making gross changes in location of such relatively large organelles as chloroplasts and nuclei. The utility of this technique for the study of cytoplasmic streaming, internal cell membranes, and organelle attachment was demonstrated.     

Ultrastructure of endocrine-like cells in lamina propria of human gastric mucosa.

Endocrine cells of gastric and gut mucosa are commonly thought to be present only within mucosal glands. In a previous report, we described argyrophilic cells in the lamina propria in 40% of surgical gastric specimens, using light microscopy. All these patients had chronic gastritis. Argyrophilia, however, is a non-specific reaction which could occur in other than endocrine cells. The present study was undertaken to describe the ultrastructure of argyrophil cells in the lamina propria. In five patients with chronic gastritis, endoscopic biopsies were taken from the fundic, intermediate, and pyloric areas of the stomach. Single and/or clustered argyophil cells were seen by light microscopy in the lamina propria of the intermediate and pyloric areas. On electron-microscopy, these cells had the following characteristics of endocrine-like cells: they were characterised by numerous electron dense granules in the cytoplasm, 100-300 nm in diameter; the cytoplasm contained poorly-developed rough endoplasmic reticulum and well-developed smooth endoplasmic reticulum with occasional vesicles. Immunostaining gave negative results for various gastrointestinal hormones. These ultrastructural characteristics of lamina propria cells are similar to endocrine cells of the APUD series. We conclude that endocrine-like cells occur in the lamina propria of the human stomach in the presence of chronic gastritis.     

Acinar cell carcinoma of the pancreas showing finger-print-like zymogen granules by electron microscopy: immunohistochemical study

A rare case of finger‐print‐like zymogen granules shown by electron microscopy is reported. The patient was a 75‐year‐old man who was histologically and ultrastructurally confirmed to have acinar cell carcinoma of the pancreas. Frozen section and postmortem examination revealed that the tumor was made up of solid nests of cells resembling the appearance of normal pancreatic acini, showing polygonal cells which had round or oval nuclei, and rare mitotic figures. Zymogen‐like granules, shown by eosinophilic granular staining, were abundant in the cytoplasm. Electron microscopy showed that the tumor cells were closely packed, occasionally forming small intercellular spaces resembling pancreatic acini (microtubules). The cytoplasm contained characteristic zymogen granules with dark‐to‐medium electron density, measuring 660 nm ± 213 SD in diameter. The granules of medium density were large, and showed finger‐print‐like patterns. Investigation of more cases is necessary to identify whether these finger‐print‐like patterns are an important factor in the genesis of acinar cell carcinoma.     

Ultrastructural-immunocytochemical localization of growth hormone and prolactin in human pituitaries.

Immunocytochemical staining using the unlabeled antibody peroxidase-antiperoxidase method was undertaken to localize and characterize in ultrathin sections of human pituitaries the cells responsible for the secretion of GH and PRL. Somatotrophs in seven pituitaries stained with human (h) PRL-absorbed antiserum to hGH, were abundant, round to ovoid, densely granulated cells, whose mean (+/-SD) granule diameter was 368 +/- 60 nm. Lactotrophs immunostained with antiserum to hPRL were less numerous, angular or branching cells, with fewer round to ovoid granules, the mean diameter (+/-SD) of which was 185 +/- 35 nm in six pituitaries. The somewhat larger PRL granules (up to a mean diameter of 360 nm) seen in two of three additional pituitaries may have been related to the previous therapeutic administration of estrogen. Whereas the immunostained GH-secreting cells resemble the presumed somatotrophs identified in other studies on the basis of nonimmunological staining, the immunostained PRL-secreting cells differ considerably from the cells with large (600--1000 nm) granules designated as lactotrophs by several previous investigators. The hazards of ultrastructural identification of human pituitary cell types on purely morphological (as opposed to immunocytochemical) grounds are emphasized.     

A 'touch' of the White platelet syndrome

Investigations into structural defects in platelets from a large family with the White platelet syndrome (WPS) separated the members into three groups. The first group of 22 members was the subject of our first report (White JG, Key NS, King RA, Vercellotti GM. The white platelet syndrome: A new autosomal dominant platelet disorder. Platelets 2004;15:173-184). A third group of 13 members had no abnormalities of platelet ultrastructure. The second group of 17 members, the focus of the present study, had a 'touch' of the WPS. Platelet counts, mean platelet volumes (MPVs) and platelet responses to aggregating agents were normal in 'touch' patients in contrast to platelets of those with the full WPS in whom these parameters were abnormal. Up to 13% of the full WPS platelets contained large, fully developed Golgi complexes, up to seven in number, extruding innumerable vesicles from the trans-Golgi face and filling the cytoplasm of many platelets. Many Golgi complexes had centrioles associated with them. 'Touch' platelets had one or two Golgi complexes of intermediate size in 3-5% of their platelets. Golgi vesicles were uncommon and centrioles absent. Gray platelets and hypogranular cells were infrequent in patients with a 'touch' of the WPS, whereas up to 44% of the platelets from those with the WPS were gray or hypogranular. Elements of the dense tubular system were prominent in full WPS platelets, together with their formation into areas of cytoplasmic sequestration and autodigestion. These features were absent in 'touch' platelets. As commonly observed in full WPS platelets, mitochondria were larger and more numerous than alpha granules in some 'touch' cells. Both 'touch' and full WPS platelets frequently contained giant and rod-shaped granules. Dense bodies, however, were normal in size and number in 'touch' platelets, and half normal size in full WPS platelets. The separation of ultrastructural abnormalities in the two varieties of the WPS suggests that genetic defects involve more than a single gene and the genes are variable in their penetrance. Genetic studies to determine if this is the case are currently in progress.     

Nuclear pores in ventricular muscle cells from adult hypertrophied hearts

Nuclear pores were observed in myocardial cells in both spontaneous and experimentally induced hypertrophy. The ultrastructure of these pores was studied in cross sections and tangential sections of hypertrophied rabbit, hamster and guinea pig heart cells. The morphology was similar to that previously seen in normal cardiac cells and in other cell types. Clusters of nuclear pores were frequently seen, and the closest center-to-center spacing between pores was 1400 Å. Annular granules with associated fibrils were observed on both the cytoplasmic and nucleoplasmic sides of the nuclear envelope. Many of the pores contained granules ～ 300 Å in diameter which sometimes appeared hollow. The presence of large numbers of nuclear pores in hypertrophied cardiac cells supports the hypothesis that transport of material necessary for RNA-mediated protein synthesis may occur through the pores. Furthermore the mature cardiocyte provides an opportunity to study nuclear pore function in nuclei that do not synthesize DNA or divide.     

斯氏狸殖吸虫卵黄细胞发育的透射电镜研究

本文描述了斯氏狸殖吸虫卵黄细胞四期发育的超微结构形态特征。卵黄细胞由第一期发育至第四期的过程中,外形由不规则而变为圆形。卵黄滴在第三期卵黄细胞的发育中形成,并沿细胞的边缘分布。高尔基氏复合体存在。粗面内质网逐惭丰富至是网络状并与核外膜相联,而至细胞成熟时又明显减少。核糖体复合物在卵黄细胞第四期的早期极为丰富,糖原颗粒在成熟的卵黄细胞中也大量增加。而当卵黄细胞退化时,这些细胞器也随之逐渐消失。并揭示成熟的卵黄细胞不仅释放卵黄滴中的颗粒球以供制造卵壳物质,而且还提供营养以助胚胎发育。