Journal of submicroscopic cytology and pathology最新文献

Histomorphology and ultrastructure of the testis during breeding and nonbreeding phases of the reproductive cycle of the lizard Mabuya carinata are studied. Observations of the ultrastructural features of the testis during breeding and nonbreeding phases of the reproductive cycle reveal a prenuptial type of spermatogenesis and a clearcut discontinuous spermatogenic cycle. Seminiferous tubules are enlarged and there is active spermatogenesis as shown by the presence of all the stages of spermatogenesis (spermatogonia to spermatids) and spermatozoa during the breeding phase (November). During the nonbreeding phase (April) only spermatogonia and Sertoli cells are seen in the shrunken seminiferous tubules. Leydig cells and Sertoli cells show distinct changes in the morphological appearance with hypertrophy of the cells in breeding phase and atrophy of the cells in the nonbreeding phase of the reproductive cycle. The present study suggests that Sertoli cells and Leydig cells functions are synchronous in the lizard M. carinata.

Beta-keratins form large part of the corneous material of scales and feathers. The present immunocytochemical study describes the fine distribution of scale- and feather-keratins (beta-keratins) in embryonic scales of the alligator and in avian embryonic feathers. In embryonic scales of the alligator both scale-keratin and feather-keratin can be immunolocalized, especially in the subperiderm layer. No immunolabeling for feather keratin is instead present in the adult scale after the embryonic epidermis is lost. The embryonic epidermis of feather folds into barb ridges while subperiderm or subsheath cells are displaced into two barbule plates joined to the central ramus. Subperiderm cells react with an antibody against feather keratin and with lower intensity with an antibody against scale keratin. The axial plate is colonized by barb ridge vane cells, which surround subperiderm cells that become barb/barbule cells. The latter cells merge into a branched syncitium and form the micro ramification of feathers. The lengthening of barbule cells derives from the polymerization of feather keratin into long bundles coursing along the main axis of cells. Keratin bundles in feather cells are however ordered in parallel rows while those of scales in both alligator and birds are irregularly packed. This observation indicates a different modality of aggregation and molecular structure between the feather keratin of subperiderm cells versus that of barbule/barbs. Barb vane ridge cells among barbule cells degenerate at late stage of feather development leaving spaces that separate barbules. Barb vane ridge cells contain alpha-keratin and lipids, but not beta-keratin. Cells of marginal plates do not contain beta-keratin, and later degenerate allowing the separation of barbs. The latter become isolated only after sloughing of the sheath, which cells contain bundle of keratin not reactive for both scale- and feather-keratin antibodies. The study confirms morphological observations and shows that subperiderm or subsheath cells differentiate into barb and barbule cells. The morphogenesis of barb ridges has to be considered as an evolutionary novelty that permitted the evolution of feathers from a generalized archosaurian embryonic epidermis.

The purpose of this study was to elucidate using transmission electron microscopy (TEM) the ultrastructural changes that occur within the cortical gray matter of a novel reproducible model of congenital hydrocephalus in mice created to overexpress the cytokine transforming growth factor-beta1 (TGF-beta1) in the central nervous system. Brain tissue was obtained from mice from a colony engineered to overexpress TGF-beta1 at two days postpartum and compared to a wild-type aged-matched control. This tissue was fixed using a solution containing 1.25% paraformaldehyde and 1.25% glutaraldehyde in phosphate buffer at least 3-4 h and then cut into 40-50 microm sections. Randomly selected thin sections were stained with uranyl acetate and lead citrate, and then analyzed using a JEOL-100CX or 1200EX transmission electron microscope at accelerating voltage 80 kV. Dramatic neuronal and glial pathology was observed throughout the cortical neuropil in TGF-beta1 mice. The most striking change in the hydrocephalic mice was severe edema with extracellular fluid, possibly due to cerebrospinal fluid (CSF) penetration into the cortex. In addition, severe disruption of the cytoplasmic matrix was seen throughout the cortex, with damage to cellular organelles and particularly severe damage to mitochondria. Our results suggest that congenital hydrocephalus may be associated with significant damage to cortical tissue.

Type V and VI collagen were capable to joint each other and with type I and IV collagen, as well as mucopolysaccharides. This capability suggested that these collagens function for cohesion of fibrillar tissue components of dermis. This study demonstrated the locality of these types of collagen in dermis. Fresh specimens of normal skin were fixed in 2% paraformaldehyde in phosphate-buffered saline, overnight. Besides, in order to loosen the twist of collagen fibril, some pieces of the skin specimens were treated by citrate buffer pH 3.0, prior to fixation. The specimens were embedded in Technovit 4100 and the ultrathin sections were stained by antibody to type V collagen and followed by antibody to type I, III, IV and VI collagen. The immune reactant was visualized by gold particles for electron microscopic observation. Type V and VI collagen formed networks in dermis and jointed to collagen fibrils, elastic fibre and basal lamina. Type V collagen was found inside collagen fibrils, broad elastic fibres and junctions. Dermo-epidermal junction showed type V collagen on the dermal aspects of basal lamina and at the sites where anchoring filaments joint to basal lamina, while in junction of mesenchymal tissues, no precise structural components for type V collagen were identified. Type VI collagen wove with type V collagen in dermis and associated with mucopolysaccharides. In conclusion, type V collagen formed networks in dermal interfibrillar space and participated in assembling collagen fibrils and forming broad elastic fibres. Epithelial and mesenchymal cells cohered to the underlying dermal matrix in the junction by type V collagen. Type VI collagen interwove with type V collagen in the interfibrous space and associated with mucopolysaccharides. Types V and VI collagen preserved architecture of dermal matrix.

The Golgi apparatus of spinal ganglion neurons was studied in 1, 3.6, 6.7, and 8.8-year-old rabbits. The structure of this organelle did not differ in the four age groups examined. While the mean volume of the neuronal perikaryon increased progressively with age, the total volume of the Golgi apparatus remained stable throughout life. As a consequence, the mean percentage of perikaryal volume occupied by this organelle decreased significantly with age. Since the percentage of perikaryal volume occupied by lipofuscin remained at low levels throughout life, the ratio of the total volume of the Golgi apparatus to the functionally active volume of cytoplasm decreased with age. It is possible that this decrease is related to the reduction in neuronal metabolism that occurs in senescence. The age-related quantitative changes in the Golgi apparatus were very similar in large light and in small dark neurons. Finally, neither fragmentation, nor peripheral displacement of the Golgi apparatus was observed with advancing age.

The epididymal epithelium of Agouti paca, a wild South American rodent, was basically formed by principal and basal cells. Principal cells were closely related to processes of adsorptive endocytosis, phase-fluid endocytosis and also secretion originating from their cytoplasmic ultrastructural features. Principal cells were also characterized by the presence of vesicles of several shapes, sizes and internalized content occurring in smaller pits, pale small vesicles next to the apical brush border of microvillus, as well as coated vesicles, smooth surface vesicles and great vesicles. Multivesicular bodies, endosomes and lysosomes were mainly observed in supranuclear position. Moreover, presence of an apocrine secretory process was demonstrated by the occurrence of apical cytoplasmic expansions projecting into the vas deferens luminal compartment. Basal flattened cells without luminal surface contact occurred next to the basement membrane of the ductus, and did no exhibit special ultrastructural features.

Submicroscopic alterations in the cytoskeletal structure of sperm flagellum are associated with severely reduced or completely absent motility in subfertile or infertile men. Sometimes these alterations can be related to well known genotypic defects when the same anomaly affects the whole sperm population. Transmission electron microscopy (TEM) is the only tool able to specifically characterize the morphological features of genetic sperm defects. In this study, the frequencies of aneuploid and diploid spermatozoa were identified in three patients showing specific flagellar anomalies, each of them affecting the whole sperm population: dysplasia of the fibrous sheath, primary ciliary dyskinesia and absence of fibrous sheath. All these defects were highlighted by TEM. Fluorescence in situ hybridization (FISH) analysis was performed on decondensed sperm nuclei for chromosomes 18, X and Y, highlighting higher diploidies and sex chromosome disomies in cases of dysplasia of the fibrous sheath and primary ciliary dyskinesia, in agreement with other reports. We have also described FISH results in spermatozoa with absence of fibrous sheath. In this case, the only one reported due to the rarity of this defect, the aneuploidies and diploidies were within normal range. These data contribute to the growing evidence that genetic sperm defects of sperm flagella are generally correlated with meiotic segregation derangement. For this reason, genetic counseling is advisable, although all the genes involved and the possible mechanisms of these mutations have not yet been fully characterized.

An infant of African-American descent presented in the immediate newborn period with secretory diarrhea, the cause of which turned out to be microvillus inclusion disease (MID). Small intestinal mucosal biopsies at 6 weeks of age were diagnostic for MID by electron microscopy and repeat biopsies from the small intestine at 15 months demonstrated the seeming relentless progression of this disorder, when a normal structure and organization of small intestinal mucosa was no longer recognizable. Since the child could not tolerate any form of enteral nutrition, a small intestinal transplant was contemplated, but could not be done. The patient did not survive the consequences of an overwhelming sepsis, which resulted in multi-organ failure.

Electron microscopic examinations are sometimes limited due to the small number of cells available for analysis. The purpose of this study was to determine the limit of cell concentration for a successful transmission electron microscopic preparation. Various concentrations of monocyte cell suspension were fixed in glutaraldehyde and osmium tetroxide according to the standard methods. Cell preparations were made on silane-coated glass slides in a cytospin centrifuge. The attached cells to the glass slides were dehydrated, and embedded in epoxy resin by routine electron microscopic technique. By this method, cell suspensions containing as low as 2x10(3) cells could show approximately 5 to 10 cells in each hole of the 150-mesh grids which was designated as the lowest limit for the successful preparation with detectable cells for evaluation. The fine structure of cells was clearly evident and the preparations were uniformly free from artifacts, similar or superior to those of cell pellet preparations. This method is useful whenever dealing with the samples containing a low number of cells, particularly those of clinical samples.