Cortical granules reaction after intracytoplasmic sperm injection

The cortical reaction (CR) in mammalian oocytes is induced following sperm-egg membrane fusion. During intracytoplasmic sperm injection (ICSI) the physiological cascade of gamete interaction events is bypassed. The aim of this study was to explore CR occurrence after the ICSI procedure and its correlation with the meiotic status of the oocytes. Unfertilized and abnormally fertilized (one- or three- pronucleate) human oocytes were investigated. The chromosomal status was analysed by Hoechst staining. The CR occurrence and its fluorescent pattern were assessed by confocal scanning laser microscope using the lectin lens culinaris and Texas Red staining. Our results reveal a positive correlation between the activation of oocytes and their CR. No CR was demonstrated in unfertilized-unactivated oocytes with or without sperm in their cytoplasm. In partially activated oocytes showing resumption of meiosis but no formation of pronuclei, a moderate CR was observed. In fully activated oocytes displaying one or three pronuclei, a strong CR was monitored. It was concluded that in ICSI, as in physiological fertilization, oocyte activation is a prerequisite for CR.      

Neoplastic argentaffin cells with intracytoplasmic eosinophilic granules in a gastric adenocarcinoma.

A case of poorly differentiated adenocarcinoma of the stomach with unique histological features is reported: in addition to characteristic adenocarcinoma cells, a large number of tumor cells contained bright eosinophilic and argentaffin granules in their cytoplasm. On routine histologic examination, the latter cells closely resembled the endocrine cells present in the normal human gastrointestinal tract, although the granules were distributed throughout the cytoplasm and did not show any polarity, which is usually subnuclear in normal endocrine cells. Immunohistochemical studies demonstrated positive staining for lysozyme, CEA, gastrin and HCG. Electron microscopic examination revealed cytoplasmic neurosecretory granules, and some tumor cells were found to contain both secretory granules and mucinous material within the same cytoplasm. These neoplastic endocrine cells presumably originated from primitive digestive system elements capable of differentiating towards both endocrine and mucus-secreting varieties.     

Ultrastructure of swine myelogenous leukaemic cells, with particular reference to intracytoplasmic granules

Seven cases of swine myeloid leukaemias were investigated by light and electron microscopy. All animals were adult sows. Morphologically these cases were classified as myeloblastic leukaemia with maturation (Cases 1 to 6) and chronic myeloid leukaemia (Case 7). The neoplastic cells were composed of immature promyelocytoid cells in Case 1. In Cases 2, 3, 4 and 5 there were immature or mature promyelocytoid cells containing peroxidase-positive granules. In Case 6, the neoplastic cells consisted of promyelocytoid cells and myelocytoid cells. The latter predominated and contained not only peroxidase-positive granules but also peroxidase-negative ones. The neoplastic cells in Case 7 showed various stages of cell maturation. The morphological characteristics in our cases resembled those in human myeloid leukaemias.     

Electron microscopic detection of statherin in secretory granules of human major salivary glands

In order to increase current knowledge regarding statherin secretion into the oral cavity, ultrastructural localization of this peptide was investigated in human salivary glands by using a post-embedding immunogold staining technique. Statherin reactivity was found inside the granules of serous cells of parotid and submandibular glands. In parotid granules immunostaining was preferentially present in the less electron-dense region, whereas in submandibular serous granules the reactivity was uniform and the dense core always stained. By contrast, none or weak reactivity was observed in serous cells of major sublingual glands. These findings reveal for the first time the subcellular localization of statherin by electron transmission microscopy and confirm that of the three major types of salivary glands, the parotid and submandibular glands are the greatest source of salivary statherin. Moreover, they suggest that more than one packaging mechanism may be involved in the storage of statherin within serous granules of salivary glands.     

Endocytosis of Class II histocompatibility antigens and formation of intracytoplasmic granules at the final differentiation stage of human B lymphocytes

The expression of histocompatibility antigens was investigated using several human lymphoid cell lines representative of different maturation stages of the B-cell lineage. Class II HLA antigens were found at the surface of all cell lines. However, in the myeloma cell line U266, an intracellular macrovesicular pool of these antigens was found in some cells. It originated from microvesicular endocytosis of the surface antigen, subsequently leading to cells bearing HLA class I but not class II antigens. Since the latter play a major role in cellular interactions regulating B-cell differentiation, this phenomenon may be linked to the final stage of maturation of B lymphocytes into plasma cells.     

Electron microscopic findings of parallel tubular granules in a case of chronic neutrophilic leukaemia.

A case of chronic neutrophilic leukaemia (CNL) is reported. The diagnosis was based on leucocytosis with mature neutrophils, a raised leucocyte alkaline phosphatase score, negative Philadelphia chromosome, and extensive infiltration of neutrophils in various differentiation stages into the bone marrow. When viewed by light microscopy, these neutrophils were almost normal in appearance, except for the presence of ring shaped nuclei and cytoplasmic vacuoles. Electron microscopy showed that neutrophilic promyelocytes and early myelocytes in the bone marrow frequently possessed unique rounded granules consisting of clustered parallel tubules, of 29-31 nm in diameter, and occasional amorphous electron dense material. These parallel tubules showed a hexagonal array; the granules were termed parallel tubular granules (PTGs). PTGs were positive for electron microscopic myeloperoxidase, and were seen exclusively in neutrophilic promyelocytes and early myelocytes. These findings suggest that PTGs represent certain primary granules peculiar to immature neutrophils. Their presence might also be helpful in diagnosing CNL.     

Electron microscopic immunogold cytochemistry reveals chromogranin A confined to secretory granules of porcine Merkel cells

By ultrastructural immunohistochemistry using the immunogold technique, immunoreactive (ir) Chromogranin A (CGA) was found to be confined to the secretory vesicles of porcine Merkel cells. CGA was present predominantly in the periphery of the electron-dense core and on the clear halo. These findings indicate that CGA is a regular constituent of Merkel cell secretory granules but probably not exclusively responsible for their electron opacity.     

Electron microscope observations on the cytoplasmic granules of a freshwater teleost (Pimelodus maculatus) leucocyte

In the present study, a hitherto undescribed granule type in the leucocytes of the freshwater teleost Pimelodus maculatus is reported. This membrane bounded elliptic granule contains straight tubules measuring from 8 to 10 nm in diameter. Almost all granules present 1 or 2 electron dense inclusions more often than not with a geometrical form. A comparison with the granules found in Prochilodus scrofa leucocytes is made.     

Human vs machine: evaluation of fluorescence micrographs

To enable high-throughput screening of molecular phenotypes, multi-parameter fluorescence microscopy is applied. Object of our study is lymphocytes which invade human tissue. One important basis for our collaborative project is the development of methods for automatic and accurate evaluation of fluorescence micrographs. As a part of this, we focus on the question of how to measure the accuracy of microscope image interpretation, by human experts or a computer system. Following standard practice we use methods motivated by receiver operator characteristics to discuss the accuracies of human experts and of neural network-based algorithms. For images of good quality the algorithms achieve the accuracy of the medium-skilled experts. In images with increased noise, the classifiers are outperformed by some of the experts. Furthermore, the neural network-based cell detection is much faster than the human experts.     

Intracellular granules of the renal medulla in a case of potassium depletion due to renal potassium wasting. Electron microscopic comparison with renal medullary granules in the potassium-depleted rat.

An electron microscopic comparison was made of intracellular granules of the renal papilla and inner medulla in two types of potassium depletion: one in a 47-year-old white male with chronic potassium-wasting renal disease and the other in the experimentally depleted rat. The granules in both cases were composed of small and large vesicles; myelin figures; small particles; and dense bodies, with a partial, or complete, single limiting membrane. Ultrastructurally, the constituent elements of the granules were essentially the same in the two types of potassium depletion. It was concluded that the intracellular granules in the human tissue were the result of potassium depletion and a counterpart to those in the potassium-depleted rat.     

Determination of the lengths of nonisotropic linear features in micrographs

The method described was devised to facilitate rapid and reasonably accurate estimations of the length of a nonisotropic linear feature in a micrograph. It arose from studies in which we were determining the length of the Purkinje cell layer in each of a set of serial sections through the rat cerebellum. The Purkinje cell layer appears as a linear feature in such sections and the simplest and most rapid method of estimating the length of this type of feature is to count the number of intersections that it makes with a series of equally spaced parallel test lines (see, e.g., Weibel, E.R., 1979: Stereological Methods Vol. 1, Practical Methods for Biological Morphometry). In many sections, the Purkinje cell layer was markedly nonisotropic, and the length obtained by this method varied very considerably depending on the orientation of the section relative to the test lines. The present method employs two orthogonal sets of parallel test lines, and the length of the feature is estimated from the square root of the sum of the squares of the counts of the number of intersections with each of the two sets of lines. The result obtained varies very little with the relative orientations of the feature and the test grid and a good estimate of the length can be obtained from the counts from a single random placement of the grid on the section. It has been found that the technique can be carried out efficiently and reliably by relatively inexperienced personnel, and the results are obtained more rapidly than when alternative methods for estimating dimensions of nonisotropic features are used.     

Sternberg-Reed cells with intracytoplasmic lymphocytes

Summary Phagocytosis by Sternberg-Reed cells is a rare phenomenon. A case of nodular sclerosis type of Hodgkin's disease with large numbers of apparently vital lymphocytes in the cytoplasm of the Sternberg-Reed cells is described in this paper. The question whether this feature is the result of phagocytosis or emperipolesis is discussed.