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M Morroni

Publications and source records attributed to M Morroni.

36 records · Page 2Linked to original sources
PubMed1990

Characterization of different microenvironments at the surface of the frog's taste organ.

We used a panel of histochemical techniques to identify and characterize the cell-associated extracellular material at the surface of the frog's taste organ. We employed morphological and histochemical techniques using both the light microscope and the electron microscope. Results show that the apical, external aspect of cells reaching the surface of the taste organ is in close contact with a layer of amorphous material. The histochemical characteristics of this material vary according to the cell type with which it is in contact. Three different microenvironments can be identified at the surface of the frog's taste organ: type 1 microenvironment is associated with the superficial layer of mucus (secretory) cells; type 2 microenvironment characterizes the surface of the so-called wing cells, which reach the surface of the taste organ as thin laminae running among mucus cells; and type 3 microenvironment shrouds the free endings of putative taste cells and is rich in calcium and lipids. Type 2 and type 3 microenvironments fix peroxidase (a sapid macromolecule) with increasing affinity. We conclude that highly differentiated microenvironments exist at the surface of the frog's taste organ, and these could play a role in the chain of biological events leading to the taste sensation. Furthermore, characterization of the cell-associated, specific microenvironments can help clarify the role of the different cell types in the frog's taste organ.

Animals↗
PubMed1990

Morphometric evaluation of intracytoplasmic lipid in normal and pathological parathyroid glands.

The chief morphological criterion for classifying parathyroid glands as 'normal', 'suppressed', or 'activated' is the lipid content of the cytoplasm. In particular, cytoplasm lipid deposit is scanty in the active parathyroid cell, according to many authors. In this paper we present the results of a morphometrical study of ten normal parathyroid glands from patients undergoing thyroidectomy, 20 enlarged 'adenomatous' glands from patients with primary hyperparathyroidism, and 20 glands of normal size from the same hyperparathyroid patients. We aimed at assessing the content of intracytoplasmic lipid of secretory cells in all these conditions. The results show that secretory cells of adenomatous glands have less lipid than those from normal glands; however, there was considerable overlapping of the data in the two groups. The mean lipid content of cells in glands of normal size taken from hyperparathyroid patients was not significantly different from the mean value of normal cells, even when ultrastructural evidence of activation was present in the former. These data suggest that caution has to be exercised in assessing the functional status of parathyroid glands on the basis of lipid content of secretory cells, mainly when differentiating between adenoma and hyperplasia.

Cytoplasm↗
PubMed1990

Bile acids reversible effects on small intestinal permeability. An in vitro study in the rabbit.

To define the action of deconjugated bile acids on the small intestinal permeability in an in vitro system, we investigated the effects of chenodeoxycholic acid and ursodeoxycholic acid on the rate of transmural flux of lactulose in jejunal and ileal mucosa of rabbits, stripped of their muscle layers and mounted in Ussing chambers. In a series of experiments, tissue samples from small intestinal segments either exposed to bile acids or not also were examined by scanning and transmission electron microscopy to study the integrity of the tight junctions. Results show that chenodeoxycholate, starting at the concentration of 0.1 mM, enhanced in a dose-related manner the transepithelial flux of lactulose in the ileum. Both chenodeoxycholate (0.5 mM) and ursodeoxycholate (0.5 mM) significantly increased mucosal permeability to lactulose in jejunum and ileum; the effect of chenodeoxycholate was also shown to be reversible, as it completely disappeared within 40 min after its withdrawal and it did not result in permanent changes of epithelial transport function. Finally, the tight junctions appeared loosened by the addition of 1 mM chenodeoxycholate, suggesting that this is the major site of the transient bile acid increase of small intestinal permeability to compounds such as lactulose, having a molecular radius wider than 0.5 nm.

Animals↗
PubMed1990

Multiple symmetric lipomatosis. Ultrastructural investigation of the tissue and preadipocytes in primary culture.

Multiple symmetric lipomatosis (MSL) is characterized by enlarging, painless fat deposits in the neck and upper trunk. The pathogenesis of MSL is unknown. Owing to localization of MSL fat deposits in the neck and interscapular region, it has been suggested that they could originate from brown fat. However, the histological appearance of MSL adipose tissue is that of white fat, with prevailing monovacuolar adipocytes. Nevertheless, MSL adipocytes are smaller than adipocytes of the common white adipose tissue and show peculiar metabolic features. The ultrastructure of MSL lesions has been not described. The present work investigated the ultrastructural morphology of MSL adipose tissue and lipomatous adipocyte precursors maintained in long-term culture. Samples of lipomatous tissue were obtained from patients affected with MSL undergoing surgical lipectomy. Portion of the tissue was processed for electron microscopy; the rest was digested with collagenase, and isolated preadipocytes from the stromal-vascular fraction were cultured up to 15 days. Cultured cells were prepared for electron microscopy in situ and their morphology compared with human white adipose tissue preadipocytes and rat brown preadipocytes cultured in parallel. Results show the following. 1) Adipocytes of MSL are not monovacuolar and resemble the largest adipocytes that can be found in rat and human brown fat. 2) Some morphological features of MSL adipocyte precursors resemble brown adipocyte more than white: cultured MSL preadipocytes transiently develop large mitochondria with parallel cristae resembling those of the brown fat cell and maintain a multivacuolar lipid deposit in culture, i.e. a typical feature of brown preadipocytes. 3) Some morphological features suggest a neoplastic nature of MSL adipocytes. Taken together, these findings suggest that MSL is a neoplastic disease which could originate in brown fat.

Adipose Tissue↗
PubMed1989

S-100 protein in white preadipocytes: an immunoelectronmicroscopic study.

Differentiation of adipocytes from their precursor cells (preadipocytes) is an important problem in the study of the pathogenesis of obesity. Unfortunately, among the immature stages of adipocytes, only relatively differentiated forms can be identified by their fine structure; because early preadipocytes cannot be distinguished from fibroblasts solely on the basis of their morphology, it is impossible to assess the size of the preadipocyte population. S-100 protein has been identified in various mammalian tissues and recently mature adipocytes have been shown to be positive for this protein. Because fibroblasts are negative for S-100 protein, the present study tested the S-100 immunoreactivity of preadipocytes by the peroxidase-antiperoxidase (PAP) preembedding method at the ultrastructural level both in vivo and in culture. Mature adipocytes and early preadipocytes, including fibroblast-like cells devoid of lipid droplets, were positive both in vivo and in culture. Endothelial cells and pericytes were negative; but flattened, lipid-free, fibroblast-like cells surrounding the pericytes were positive. True fibroblasts both in vivo and in culture were negative. Therefore, S-100 protein can be a useful biochemical marker in distinguishing fibroblasts from early preadipocytes.

Adipose Tissue↗
PubMed1989

Pachydermoperiostosis (primary hypertrophic osteoarthropathy): report of a case with evidence of endothelial and connective tissue involvement.

A case of pachydermoperiostosis characterised by the presence of finger clubbing, periostosis, sweating of hands and feet is described. Modifications of capillaroscopic pattern and of arteriovenous anastomoses are reported. The periungual border and finger tip tissue showed diffuse endothelial hyperplasia, hyalinosis, and sclerosis with packing of collagen fibres. Electron microscopy showed hypertrophic and activated endothelia (numerous and hypertrophic Golgi complexes, several Weibel-Palade bodies, vesicles of micropinocytosis, and glycogen particles), the basal membrane thickened and reduplicated, perivasal infiltrate in superficial derma, reticulation and segmentary reduplication of basal membrane in arteriovenous shunt. In the perineural connective tissue numerous Luse bodies (long spacing collagen) were evident. The data indicate that in the early phase of pachydermoperiostosis morphological endothelial and collagen fibre abnormalities are present, though there is a normal peripheral blood flow.

Adult↗
PubMed1989

Scanning electron microscopy of the small intestine mucosa in children with celiac disease after long-term dietary treatment.

Jejunal mucosal specimens from twenty children with celiac disease were studied by light microscopy (LM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) after one year of dietary treatment. An ultrastructural morphometric study was performed in five patients who had an intestinal permeability (IP) test. Seventeen patients were tested for serum antigliadin antibodies (AGA). In ten children, in whom LM showed partial villous atrophy, SEM and TEM examination confirmed the lesion. In the second group (10 children) with normal morphology at routine LM, SEM showed lesions of variable degree in 70% of cases. The morphological ultrastructural investigation showed good correlation with the immunological and functional data (IP test): ultrastructural damage of the jejunal mucosa after one year of a gluten-free diet was found in patients with positive serum AGA and an abnormal IP test. Furthermore, the morphometric study of the ultrastructural alterations allowed a quantitative, closer correlation between morphological and functional data. Our results suggest: 1) SEM and TEM investigations offer additional and more complete information on celiac patients, over LM alone. 2) The morphometric evaluation of the ultrastructural alterations highlights quantitative and reproducible correlations between morphological and clinical data, not strengthened by the subjective, qualitative study.

Adolescent↗
PubMed1988

Diabetic hand syndrome.

Diabetic hand syndrome is a condition affecting about 30% of patients with insulin-requiring juvenile diabetes. Characteristic findings in this syndrome are mild- to- moderately severe joint contractures of the fingers, particularly at the proximal interphalangeal joints in the ring and small fingers, and thickening of the skin of the dorsum of the hand. There is no evidence of palmar fascial thickening or Dupuytren's contracture. Occasionally other joints may be involved, such as the wrists, elbows, hips, knees, and toes. In the case presented in this report light and electron microscopic studies showed that the disease presents aspects similar to those of other "fibrotic diseases" as described by Kisher and Speer. Surgical treatment was only partially beneficial in this patient.

Child↗
PubMed1986

Human thymocyte differentiation: an ultrastructural study using monoclonal antibodies and immunogold staining method.

The ultrastructural features of normal human thymocytes were analyzed at various stages of immunologic differentiation as defined by a panel of OKT monoclonal antibodies visualized by colloidal gold labelled antimouse IgG. The study shows that first stage thymocytes (OKT10+, OKT9+) have a typical morphology not found in more mature stages and describes the critical ultrastructural change which they undergo in becoming second stage thymocytes (OKT10+, OKT6+, OKT8+, OKT4+). No change in thymocyte fine morphology has been found in the progression from second to third stage (OKT10+, OKT3+, OKT8+ or OKT10+, OKT3+, OKT4+). Cells with ultrastructural features intermediate between those of the first and second stage have been found to react with monoclonal antibodies characterizing the first and the second stage. Ultrastructural similarity and homogeneity found in OKT8+ and OKT4+ thymic subpopulations suggests the acquisition by T lymphocytes of morphologic structures correlate with immunologic features previously found in peripheral blood T cell subpopulations to be a post-thymic process.

Antibodies, Monoclonal↗
PubMedDate not supplied

Stages of development of the ribosome-lamella complex: an ultrastructural study.

Ribosome-lamella complexes (RLC) are intracytoplasmic organelles observed in a wide variety of disorders, but mostly in hematologic malignancies. Although their close topographic relationship with rough endoplasmic reticulum (RER) suggests their derivation from it, their development and functional role are unclear. Their maturation phases were studied in 20 cases (19 hematologic neoplasms and 1 parathyroid adenoma) where electron microscopy had evidenced their presence. In 19 of thesecases, RLC were in an advanced stage of maturation, whereas in one (acute monoblastic leukemia) they were observed in the early stages of development and appeared to arise from peculiar RER configurations within blast cells, which were rich in both organelles. In this case, the authors observed numerous RER cisternae with distinctive cylindric, concentric and/or whorl configurations, RLC associated and not associated with these configurations, and intermediate structures. The latter were characterized by lamellae devoid of ribosomes oriented parallel to the RER configurations. Reticulum configurations were observed in no other case. The ultrastructural aspects observed in these 20 cases suggest that RLC synthesis proceeds as follows: (1) arrangement of RER in cylindric configurations; (2) synthesis of lamellae oriented parallel to the cylindric configurations (pre-RLC); (3) formation of RLC when ribosomes appear between the lamellae associated with configurations (immature RLC); (4) formation of mature RLC with disappearance of the reticulum.

Blood Platelets↗
PubMedDate not supplied

Hairy cell leukemia: an ultrastructural study of hairy cells before and after interferon therapy.

AIMS AND BACKGROUND: To test the diagnostic relevance of the presence of ribosome-lamellae complexes (RLC) in 18 hairy cell leukemia (HCL) cases, and to correlate clinical response to interferon (IFN) therapy with hairy cell ultrastructural modifications in 5 of these cases. METHODS: Peripheral blood samples of 18 HCL patients were studied by transmission electron microscopy. Five of these patients received IFN treatment and subsequently were evaluated at different intervals for ultrastructural modifications of the peripheral blood. RESULTS: RLC were observed in 66.66% of our 18 HCL patients, but in less than 1% of all the cases contained in the files (consisting of over 8,000 cases) of our Electron Microscopy Unit. The microvilli disappeared after IFN therapy in the patients who did not display RLC before therapy (2 cases), whereas they were fewer, shortened and blunted, but still evident, in the cases where RLC had been observed before therapy (3 cases). Moreover, in the HCL cases with pretherapy RLC, neoplastic cells still synthesized RLC after IFN treatment, but their morphologic aspect was immature. CONCLUSIONS: Our study suggests that: 1) the presence of RLC, when associated to the hairy aspect of the cells, has considerable diagnostic value even though RLC are observed in other rare neoplastic and non-neoplastic conditions; 2) HCL cases with pre-therapy RLC exhibited a morphologic response to IFN therapy different from that of cases without pre-therapy RLC; 3) the quantitative and qualitative modifications of RLC following IFN treatment, as yet unexplained, are probably related to IFN action, in line with a previous report.

Adult↗
PubMedDate not supplied

Direct demonstration of cytokeratin filaments by electron microscopy in K562 cell lines in liquid culture.

Our previous study suggested the presence of cytokeratins in the supernatant of human K562 erythroleukemic cell line. In this study we confirm, by using an electron microscopy technique, that K562 cells contain typical intermediate tonofilaments with the characteristics of cytokeratins. After variable intervals of liquid culture, K562 cells have been examined for their clonogenic ability by immunostaining and ultrastructural study. K562 cells showed variable amounts of medium-sized filaments (intermediate filaments) of 10 nm mean size, having the submicroscopic pattern consistent with tonofilaments, arranged as electron-dense curve-shaped bundles, in perinuclear position independently from the different growth phases. A pool of monoclonal antibodies against cytokeratins confirmed the presence of cytokeratins in immunostaining, while the cytofluorimetric analysis showed an unexpected positivity of the CD34 antigen, associated with the typical adhesion molecule VLA5. In conclusion, the immunostaining with monoclonal antibodies and the ultrastructural findings suggest the expression of epithelial features in human K562 leukemic cells.

Cell Culture Techniques↗