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A Sbarbati

Publications and source records attributed to A Sbarbati.

At least 109 records · Page 6Linked to original sources
PubMed1986

Ultrastructure of brown adipocytes mitochondria in cell culture from explants.

Brown adipocytes lose in culture their typical mitochondria, which are replaced by others of non typical morphology. During studies aimed at clarifying this phenomenon we found that better preservation of the 'typical' mitochondrial morphology is obtained in vitro after a long period of time, when cells from small fragments (explants) of brown adipose tissue (BAT) are cultured instead of collagenase-isolated brown adipocytes. These results suggest that the explant technique could be better suited to study brown adipocytes in culture than other methods employing collagenase-isolated cells.

Adipose Tissue, Brown↗
PubMed1985

Inflammatory malignant fibrous histiocytoma of the kidney: an immunohistochemical and ultrastructural study.

A primary inflammatory malignant fibrous histiocytoma of the kidney is reported. The differential diagnosis from other sarcomas and pseudosarcomatous lesions is discussed on the grounds of the histologic, immunohistochemical and ultrastructural results. The neoplasm was made up of histiocytes, fibroblasts, myofibroblasts, foam cells and undifferentiated mesenchymal cells with admixed granulocytes, lymphocytes and plasma cells. The immunohistochemical study showed a positivity for alpha-1-antichymotrypsin and a weak positivity for alpha-1-antitrypsin in mononuclear and pleomorphic multinucleated tumor cells. PAS-positive, diastase-resistant intracytoplasmic hyaline globules in necrotic cells, examined by electron microscopy, most likely represent lysosomal structures, in accordance with the theories of De Duve, Vattiaux and Von Ardenne.

Female↗
PubMed1985

An ultrastructural morphometric analysis of the adenohypophysis of lactating rats.

A morphometric analysis of the adenohypophysis (pars distalis) of lactating rats was carried out by a semi-automated method at the ultrastructural level. The cellular elements were identified by their ultrastructural morphology. The following values were considered for the morphometric study: numerical density of cells/mm3 of tissue and the percentage of parenchymal volume occupied by every cell type. Mammotropes (PRL cells) numbered 624 X 10(3)/mm3 and occupied 59.9% of the parenchymal volume (p.v.). Somatotropes (GH cells) numbered 206 X 10(3)/mm3 and occupied 15.0% of the p.v. Folliculo-stellate cells (FS cells) numbered 128 X 10(3)/mm3 and occupied 8.1% of the p.v. Gonadotropes (GN cells) numbered 47 X 10(3)/mm3 and occupied 6.0% of the p.v. Adrenocorticotropes (ACTH cells) numbered 45 X 10(3)/mm3 and occupied 3.8% of the p.v. Thyrotropes (TSH cells) numbered 36 X 10(3)/mm3 and occupied 3.4% of the p.v. PRL cells were characterized by aspects compatible with intense hormone production. GH cells did not show differences with those of nonlactating animals. Folliculo-stellate elements appeared hypertrophic with abundant cytoplasm, enlarged Golgi complex, and dilation of the follicular lumina. GN cells had abundant cytoplasm with a well-developed and dilated ergastoplasm, particularly in type II GN cells. ACTH cells did not show differences with those of nonlactating animals. TSH cells showed moderate nucleocytoplasmic activation. These fine structural morphometric findings are discussed in relation to other studies regarding nonlactating adenohypophysis and hormone changes during lactation.

Adrenocorticotropic Hormone↗
PubMed1985

An ultrastructural study on muciparous microcysts of the human adenohypophysis.

The microcysts found in two adenohypophyses removed from patients with nonsecreting adenomas of this gland have been studied. In one case the cysts were completely surrounded by neoplastic tissue, whereas in the second they were located within the normal parenchyma. The cysts were surrounded by a basement membrane, and appeared to contain a finely granular weakly electron-dense substance. Their walls were lined by mostly cubic cells with microvilli, joined by junctional complexes. Intracytoplasmic microlumina could be seen in some of these cells. Cells showing cilia with a 9 + 2 fibrillar pattern and cells with mucosecretory differentiation were also present. Furthermore endocrine cells were also found in the cyst-lining epithelium. The ultrastructural aspects of the cyst cells lead to reject the hypothesis that these are derived from folliculostellate cells. Besides, intermediate aspects between cyst cells and tumor cells were never visible. Therefore it seems likely that a relationship between adenoma and cyst cells does not exist and that cyst cells originate from remnants of Rathke's pouch with a ciliate or mucosecretory differentiation. The presence of endocrine cells in the cyst-lining epithelium deserves further study, for it seems to indicate that an endocrine differentiation may occur in the adult, too. To our knowledge this is the first ultrastructural study of these structures in adult human pituitary gland.

Adolescent↗
PubMed1984

Ultrastructural aspects of nailfold capillaries in a case of eosinophilic fasciitis.

An ultrastructural study was made on the nailfold capillaries in an 18-year-old female with eosinophilic fasciitis. Scleroderma-like capillaroscopic lesions were visible at the sites where biopsy was performed. Light microscopy revealed ectasic capillaries at the apex of dermal papillae. Aspects of thickening and duplication of the epidermal basement membrane as well as an activation of endothelial cells were visualized at the ultrastructural level. These cells contained many virus-like tubulo-reticular inclusions, associated with cisternae of endoplasmic reticulum. Aspects of degeneration of nerve fibres and Schwann cells were also present. Large, homogeneously electron-dense deposits could be seen in the basement membrane at the dermo-epidermal junction. This study not only confirms previous observations on the microangiopathy in eosinophilic fasciitis, but also documents two new aspects: electron-dense deposits at the dermo-epidermal junction and tubulo-reticular inclusions within endothelial cells.

Adolescent↗
PubMed1983

[Ultrastructural study of the stellate cells of the adenohypophysis in an ovariectomized woman].

We have studied at the E.M. the adenohypophysis removed from a woman who had undergone bilateral ovariectomy 4 months earlier because of a disseminated breast cancer. Our study has focused on the submicroscopic aspects of follicular-stellate cells, whose function has not yet been fully ascertained, though it is known from studies carried out on laboratory animals, that these cells are activated under conditions of stimulus to hyperactivity of one or more of the cell types of the adenohypothysis. In our material we have observed numerous follicular structures with variable amounts of colloid-like substance. Follicular-stellate cells limiting colloid-filled cavities showed many cytoplasmic organules with hypertrophic Golgi complex, intracytoplasmic lumina, interdigitations of the cytoplasmic membranes. These aspects are consistent with a condition of hyperactivity of follicular-stellate cells due to bilateral ovariectomy.

Adult↗
PubMed1983

[A new model for the in vivo study of adipocyte precursors in the rat].

Periepidydimal fat pad of young rat shows, in the peripheral zone, areas with lobular aspect and areas with flattened aspect, surrounded by a mesothelial sheath. In adult rats the flattened areas are no longer observed. The ultrastructural study of the cells present in the flattened zones of the periepidydimal fat pad and the comparison with the same tissue of adult rats seems to indicate that the flattened areas in the peripheral zone of the periepidydimal fat pad of the young rat are a site where the adipocyte precursors can best be studied. Furthermore in the pericytes of the blood vessels wall, rare little lipid vacuoles can be seen: this is in accordance with the hypothesis proposed by other autøhors that the precursors of the adipocytes derive from pericytes.

Adipose Tissue↗
PubMed1983

[Submicroscopic study of brown adipose tissue in young rats by the freeze-fracturing method].

The authors report the results of their ultrastructural study on the rat brown adipose tissue using the freeze-fracturing techniques. It is well known from transmission electron microscopy that lipid vacuoles of the brown adipose tissue cells are bound by a dense line corresponding to a structure as yet totally unknown. The results of the study using freeze-fracturing technics show that the morphology of lipid vacuoles surface is different from that of the typical unit membrane. The possibility is discussed that the particular aspect of the surface is due to the lypolysis induced by tissue fixation.

Adipose Tissue, Brown↗
PubMed1982

[An ultrastructural immunocytochemical study of secretory granules of an adenohypophyseal tumor].

The unlabeled antibody peroxidase-antiperoxidase complex technique was used to stain for electron microscopy the secretory granules of a pituitary tumor that had been surgically removed from a woman with high serum prolactin levels. Granules were stained using anti-human prolactin serum. The diameter of the secretory granules was smaller than that measured for the granules of prolactin producing cells in normal human pituitary glands. A shortened storage phase would explain the diameter reduction.

Cytoplasmic Granules↗
PubMed1982

[Ultrastructural changes in the mammary gland of the lactating rat induced by treatment with bromocriptine].

The authors report the results of their ultrastructural study on the lactating mammary gland of the rat treated with bromocriptine. On the sixth day of treatment the mammary gland shows the same morphological features of the physiologically involuting mammary gland and the same morphological features of the mammary gland of the rat whose pups have been taken away. These results suggest that the pharmacologic treatment with bromocriptine induces a physiological involution of the lactating mammary gland in the rat and that the same drug abates the effect of the persisting suckling stimulus.

Animals↗
PubMedDate not supplied

Evaluation of frog gastric mucous secretion by 7T magnetic resonance imaging.

This work describes a new method to evaluate the action of drugs on gastric mucus secretion by 7 T MRI. A polyethylene probe was inserted into the stomach of frogs, a water washing cycle was performed, air was inflated into the stomach, and the probe was removed. Drugs were administered topically by mixing them with the water used for stomach washing, and a series of images was collected. In untreated animals, a mucous layer emitting a high intensity signal covered the gastric mucosa. Atropine administration strongly reduced the mucous layer thickness. After pilocarpine administration, MRI images showed that the mucous layer was thicker than in controls. After metacholine administration, the thickness of the mucous layer was increased in comparison with both controls and pilocarpine-treated animals, in accord with the expected drug-induced increase of mucous secretion. Quantitative analysis of the mucous layer thickness on MRI images confirmed the above findings. In conclusion, these results indicate that MRI at 7 T is a sensitive in vivo screening test to evaluate the effect of drugs on gastric mucus secretion in absence of surgical manipulation, thereby enabling morphofunctional studies that cannot be performed by conventional methods.

Animals↗
PubMedDate not supplied

Rapid diagnosis of fungal infection of intravascular catheters in newborns by scanning electron microscopy.

Intravascular catheters carry a significant risk of becoming colonized with bacteria and fungi and are important risk factors of septicemia in premature neonates. The study was undertaken to evaluate whether scanning electron microscopy (SEM) examination of removed catheters can be useful in early diagnosis of plastic infection by Candida, providing information useful for initiation of an eventual therapy. The evolution of biofilms in 28 catheters (umbilical or central) implanted in 24 newborns for prematurity was studied by SEM and transmission electron microscopy (TEM). In 4 of 24 patients, SEM examination revealed the presence of Candida in form of yeast or hyphae. In one of these patients, TEM confirmed the presence of organisms. In each case, hemoculture and culture of the catheter itself confirmed the diagnosis. The study demonstrates that SEM can identify fungi in the biomaterials covering the catheter surface in a few hours, allowing an early diagnosis of plastic infection.

Biofilms↗
PubMedDate not supplied

Ultrastructural phenotype of "intestinal-type" cells in columnar-lined esophagus.

An intestinal-type epithelium is often present at columnar-lined esophagus, gastroesophageal junction or within the so-called short segment Barrett's esophagus, but ultrastructural study failed to detect enterocytes in columnar-lined esophagus. The authors have analyzed the intestinal aspects present in areas of columnar-lined esophagus in a population of patients with reflux esophagitis to better understand the morphology and histogenesis of the proliferating elements. Columnar-lined mucosa was studied in 35 patients. Columnarsurface cells displayed a wide spectrum of ultrastructural features. Well-differentiated columnar secretory cells, secretory-absorptive cells, poorly differentiated columnar cells, atypical columnar cells, and goblet cells were detected. Well-differentiated absorptive cells were never found, These results demonstrate that the areas of intestinal metaplasia show a wide spectrum of ultrastructural phenotypes, ranging from poorly to well-differentiated cells. However, true enterocytes were not found and the most represented phenotype is that of secretory-absorptive cells, whose principal characteristic is the presence of secretory and absorptive aspects together. They can be described as secretory enterocytes or cells with double specialization. To the authors' knowledge, similar cells were not previously described in normal intestinal mucosa, and ultrastructural studies are consistent in describing a broad spectrum of ultrastructural features, suggesting that Barrett's specialized metaplasia is derived from cells with the capacity for a wide range of differentiation. Therefore, despite the wide use of term intestinal metaplasia in the medical literature, experimental data clearly failed to detect enterocytes in the columnar-lined esophagus, and ultrastructural data do not support the concept of intestinal metaplasia. The cellular heterogeneity seems to be the result of a "phenotypic shift" of undifferentiated elements, which show a different pattern of evolution. The result of this process is the formation of new cell types dissimilar from those normally present in esophageal, gastric, or duodenal mucosa.

Adolescent↗
PubMedDate not supplied

Ultrastructural findings in the jejunal mucosa of children with IgA deficiency.

The primary aim of this work was to investigate the ultrastructural morphology of the small intestinal mucosa in children affected by selective IgA deficiency (SIgAD). Absorptive tests and intestinal biopsies were performed in a group of nine children with SIgAD, none of them presenting with diarrhea. Biopsy specimens were processed for routine histology and scanning or transmission electron microscopy (SEM and TEM). By light microscopy, the jejunal mucosa appeared normal in all but one patient with patchy villous atrophy. By SEM, two further biopsies showed small areas of flat mucosa surrounded by villous ridges of nearly normal height. By TEM, four out of the nine mucosal specimens showed degenerative changes of the surface epithelium, including enlargement of the mitochondria, apical accumulation of primary and secondary lysosomes, and shortening and branching of the microvilli. These findings suggest that the small intestinal mucosa of children with SIgAD often shows pathological changes, some of which are recognizable only at the ultrastructural level. The study of biopsy specimens by SEM seems to be a useful diagnostic tool when patchy mucosal damage may occur, as in some of our patients with SIgAD.

Child↗
PubMedDate not supplied

Unresponsive enteropathy associated with circulating enterocyte autoantibodies in a boy with common variable hypogammaglobulinemia and type I diabetes.

A 13-year-old boy with common variable hypogammaglobulinemia and type I diabetes developed a severe enteropathy that proved to be unresponsive to any treatment, including total parenteral nutrition. No evidence of known etiologies of malabsorption and/or secretory diarrhea was found in this subject. A high titer of complement-fixing enterocyte autoantibody was persistently found in the patient's serum. These features suggest that the enteropathy of this primarily immunodeficient subject had an autoimmune origin. A cycle of cyclophosphamide failed to show any amelioration of the diarrhea or a significant decrease in the autoantibody titer.

Adolescent↗