Syndecan expressions in the human amnion and chorionic plate.

The syndecan family consists of four distinct membrane glycoproteins in mammals. Syndecans control cell proliferation, differentiation, adhesion and migration through participation in cell-cell interactions, anchorage of cells to the extracellular environment, and modulation of multiple growth factors. Therefore, syndecans may play a pivotal role in the regulation of cell behaviour depending on the cellular microenvironment. Here, we demonstrate that syndecan-1, syndecan-2 and syndecan-4 are expressed in fetal membrane tissue with different immunolocalizations. Syndecan-1 is expressed in the amniotic epithelium, localizing at basolateral cell surfaces. Syndecan-2 and syndecan-4, in contrast, are mostly localized in intracellular compartments, in the extravillous cytotrophoblastic cells and in some fibroblasts of the chorionic plate as well as in the amniotic epithelial cells. In the latter, syndecan-4 is mainly localized in the apical part of the cells. Our results strongly suggest a key role of syndecan-1, syndecan-2 and syndecan-4 in the determination of structural and functional characteristics of human amnion and chorionic plate. Since the solute exchanges between fetus and mother take place in fetal membranes, our data suggest that syndecans are important players in the placenta for the establishment of the fetal-maternal inter-communication.

Expression of basic fibroblast growth factor, its receptors and syndecans in bladder cancer.

Basic fibroblast growth factor (bFGF) is a heparin-binding cationic protein involved in a variety of pathological conditions including angiogenesis and solid tumour growth. The basic fibroblast growth factor receptor (FGFR) family comprises at least 4 high affinity tyrosine kinase receptors that require syndecans for their function. Mounting evidence indicates that syndecans, that bind both bFGF and their FGFRs, will act as stimulators, whereas syndecans that only bind bFGF will act as inhibitors of signaling by sequestering the growth factor. Recent findings have highlighted the importance of syndecans in urological cancers. The aim of this study is to investigate the expression of bFGF, its receptors (R1 and R2) and syndecans (1-4) in invasive urothelial carcinoma and normal-looking urothelium by Western blotting, RT-PCR, and immunohistochemistry analyses. Interestingly, bFGF, FGFR1 and FGFR2 protein levels statistically increased in bladder cancer tissues. mRNA of FGFR1 and syndecans (1-4), showed a statistically significant increase while an mRNA increase in the other molecules analysed was not significant. bFGF, its receptors and syndecan immunostaining were mainly present in the urothelium both in normal-looking tissues and urothelial neoplastic cells. In conclusion, our data report that the bFGF, FGFR and syndecan expressions are altered in bladder tumours.

Remodeling of uterine innervation.

This minireview reports current hypotheses concerning the remodeling of sympathetic innervation in rodent and human uterus during the estrous cycle and gestation. Neural modulation in this organ is related to sexual hormone concentrations, and a reduction in nerve density is observed when estrogen levels are high during the estrous cycle. Estrogen receptor alpha is considered to be the major receptor mediating the action of estrogen. In the uterus, the expression of neurotrophins, such as nerve growth factor, which are involved in the survival and growth of nerve fibers, changes in response to steroid levels. Despite much research, further studies are necessary to clarify various aspects of nerve growth control under diverse physiological conditions. These studies could be of importance, since alterations of the biological mechanisms of uterus innervation may play significant roles in various pathologies, such as infertility and spontaneous abortion.

In vivo leptin expression in cartilage and bone cells of growing rats and adult humans.

The present investigation was carried out to analyse, immunohistochemically, in vivo leptin expression in cartilage and bone cells, the latter restricted to the elements of the osteogenic system (stromal cells, osteoblasts, osteocytes, bone lining cells). Observations were performed on the first lumbar vertebra, tibia and femur of four rats and on the humerus, femur and acromion of four patients. Histological sections of paraffin-embedded bone samples were immunostained using antibody to leptin. The results showed that, in growing rat bone, leptin is expressed in chondrocytes and stromal cells, but not in osteoblasts; bone lining cells were not found in the microscopic fields examined. In adult human bone, leptin is expressed in chondrocytes, stromal cells and bone lining cells; osteoblasts were not found in the microscopic fields examined. Osteocytes were found to be leptin positive only occasionally and focally in both rat and human bone. The in vivo findings reported show, for the first time, that leptin appears to be expressed only in the cells of the osteogenic lineage (stromal cells, bone lining cells, osteocytes) that, with respect to osteoblasts, are permanent and inactive, i.e. in those cells that according to our terminology constitute the bone basic cellular system (BBCS). Because the BBCS seems to be primarily involved in sensing and integrating mechanical strains and biochemical factors and then in triggering and driving bone formation and/or bone resorption, it appears that leptin seems to be mainly involved in modulating the initial phases of bone modelling and remodelling processes.

Gluten sensitivity and 'normal' histology: is the intestinal mucosa really normal?

BACKGROUND: Early pathogenetic events of gluten intolerance may be overlooked in patients with serologic markers of celiac disease and normal intestinal mucosa by both conventional histology and immunohistochemistry. AIMS: To investigate if a submicroscopical damage of the absorptive cell surface was associated with developing gluten sensitivity. PATIENTS AND METHODS: Duodenal biopsies of seven subjects with positive anti-endomysial antibodies and normal histology underwent ultrastructural evaluation of the epithelial surface by means of both scanning and transmission electron microscopy. Specimens of intestinal mucosa of 14 children with non-celiac conditions were used as controls. RESULTS: In four patients, electron microscopy revealed alterations of the enterocyte brush border with a significant reduction of the height of microvilli. After several months, three of them had a second biopsy that eventually showed histological modifications suggestive of celiac disease. In the other three patients, no significant alteration of enterocyte ultrastructure was observed. One of them, rebiopsied after 12 months, still showed a normal duodenal histology. CONCLUSIONS: Gluten sensitivity can be associated with 'minimal' mucosal changes not detectable with conventional light microscopy. Such lesions, which primarily involve microvillous structure, may imply a reduction of intestinal absorptive surface already in the latent stage of the disease.

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.

Primary alveolar soft part sarcoma of the stomach: a case report and review.

Alveolar soft part sarcoma (ASPS) is a rare tumor typically located in skeletal muscles and muscolofascial planes. Isolated cases of ASPS have been described as arising in the viscera. We report a mesenchymal tumor of the stomach in a 54-year-old Italian woman without evidence of primary neoplasm elsewhere ten years following the initial diagnosis. The histologic, histochemical, immunohistochemical, and electron microscopic findings were all consistent with the diagnosis of ASPS and allowed differentiating it from morphologically similar and more common tumors, such as metastatic renal cell carcinoma and paraganglioma. The patient is alive and well ten years following the initial presentation.

Sensory nerves affect the recruitment and differentiation of rat periovarian brown adipocytes during cold acclimation.

Rat periovarian adipose tissue contains a low number of uncoupling protein-expressing brown adipocytes scattered into lobules of white fat. Their increase following cold acclimation is matched by a major increase in noradrenergic and neuropeptide Y-, substance P- and calcitonin gene-related peptide-containing nerves. To ascertain whether periovarian fat is provided with sensory nerves, and whether any relationship exists between such nerves (in particular the calcitonin gene-related peptide-containing fibers found in cold-acclimated rats in close association with brown adipocytes) and brown fat recruitment, the effects of capsaicin desensitization on neuropeptide-containing nerves and brown adipocyte density were studied in the periovarian tissue of rats kept at 20 degrees C and on a group acclimated to 4 degrees C for 14 days. In both groups, systemic capsaicin administration considerably reduced the expression of substance P and calcitonin gene-related peptide in vascular-nerve bundles and parenchyma. In cold-acclimated rats, the increase in brown adipocyte density was significantly checked by capsaicin administration (21.11 versus 7.96 brown adipocytes/mm2, P<0.05). Finally, ultrastructural investigation showed the occurrence of brown adipocyte precursors filled with aggregates of glycogen and poorly differentiated multilocular adipocytes in capsaicin-treated cold-acclimated rats. These data suggest that periovarian adipose tissue is indeed provided with sensory neuropeptide-containing nerves and that they play a role in the recruitment and differentiation of brown adipocytes.

Hypomelanosis of Ito: a case report with clinical and ultrastructural data.

Hypomelanosis of Ito (HI) is an uncommon skin disorder characterized by the presence of hypochromic areas associated with visceral abnormalities, the most common being neurological, muscular, skeletal and ocular. The authors describe a typical case of hypomelanosis of Ito in a 7-year-old child. The patient was obese, suffered from scoliosis, flat feet and had a bilateral genu valgus. No neurological, ophthalmological or dental malformations were noted. An electron microscopic study of a hypomelanotic area showed decreased functional activity in the melanocytes, which contained only a few rudimentary cytoplasmatic projections and poorly developed organelles. In addition, there was a reduction in the number of mature melanosomes.

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.

Codistribution of basic fibroblast growth factor and heparan sulfate proteoglycan in the growth zones of the human placenta.

In order to obtain an insight into morphogenetic processes such as angiogenesis, cell proliferation, and tissue remodeling we have studied the localization of basic fibroblast growth factor (bFGF) and heparan sulfate proteoglycan (HSPG) in the human placenta by immunohistochemistry. Positive reaction product for bFGF is found mainly in the villous trophoblastic covering and for HSPG in the villous basement membranes. A codistribution of the two molecules is detectable in first trimester placental tissue, in areas previously identified as being responsible for the growth of the villous tree, i.e., in the mesenchymal villi and the cytotrophoblastic cell islands and cell columns, both consisting of extravillous trophoblast. HSPG and bFGF are codistributed in the distal half of the villous stroma in the mesenchymal villi. In cell islands and cell columns, bFGF is detectable in the cytoplasm of the extravillous cytotrophoblastic cells, whereas HSPG is localized between the extravillous cytotrophoblastic cells and in their cytoplasm. HSPG-bFGF codistribution in term placenta is confined to the walls of fetal vessels and to some extravillous cytotrophoblastic cells in the basal plate. The codistribution of bFGF and HSPG in first trimester placental tissue suggests that these two molecules play a pivotal role in the morphogenetic processes mentioned above in early stages of gestation.

Tyrosine hydroxylase, neuropeptide Y, substance P, calcitonin gene-related peptide and vasoactive intestinal peptide in nerves of rat periovarian adipose tissue: an immunohistochemical and ultrastructural investigation.

Rat periovarian adipose tissue contains unilocular adipocytes and some multilocular adipocytes that, following acclimation to cold, become more numerous and give rise to periovarian brown fat areas. We studied the occurrence and distribution of tyrosine hydroxylase, neuropeptide Y, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide, methionine enkephalin, neurotensin, galanin, and cholecystokinin 9-20 in the nerves of rat periovarian tissue maintained at 20 degrees C (control rats), acclimated at 4 degrees C (cold acclimated rats) and at 28 degrees C (warm-acclimated rats). In the periovarian tissue of control and warm-acclimated rats, tyrosine hydroxylase-like, neuropeptide Y-like, substance P-like and calcitonin gene-related peptide-like immunoreactive elements (putative nerves) were present in the blood vessels. In the periovarian tissue of cold-acclimated rats, we found: (1) a more widespread vascular distribution of these neuropeptides; (2) tyrosine hydroxylase-like and calcitonin gene-related peptide-like immunoreactive elements among paucilocular and multilocular adipocytes (parenchymal-like nerves); (3) vasoactive intestinal peptide-like immunoreactive elements in some arteries. Investigation by EM showed the presence of heterogeneous non-myelinated axons both associated with capillaries and among paucilocular and multilocular adipocytes (parenchymal fibres) in periovarian brown fat areas. In conclusion, periovarian brown fat contains the same neuropeptides, with the same vascular and parenchymal distribution, already seen in typical depots of brown fat.

Subcutaneous nodules in a patient hyposensitized with aluminium-containing allergen extracts: a microanalytical study.

Electron spectroscopic imaging (ESI) is a recent tool for electron microscopic analysis which permits the recognition of the distribution of elements in a specimen, with a spatial resolution up to 5 nm. The authors performed the ESI together with X-ray microanalysis (EDX) and transmission electron microscopy to study granulomatous subcutaneous nodules in a patient who had undergone a desensitising therapy with an aluminium-containing vaccine. Aluminium was detected both by EDX and ESI, mainly in lysosomes of histiocytes containing needle-shaped material in a lucent matrix. However, ESI provided a better localization of aluminium with respect to EDX. This result suggests that the identification of aluminium-containing structures cannot be obtained only by ultrastructural morphology and underlines the utility of a microanalitycal study for a correct diagnosis in the presence of a needle-shaped deposition of dense material in lysosomes.

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.

Immunohistochemical, ultrastructural and morphometric evidence for brown adipose tissue recruitment due to cold acclimation in old rats.

OBJECTIVE: The aim of this work was to study the reactivity to chronic cold stress of interscapular brown adipose tissue (IBAT) in old rats by stereological, immunohistochemical and ultrastructural methods. DESIGN: Five 2-year-old rats were cold-acclimated at 4 degrees C for 4 weeks and six rats were used as controls (20-23 degrees C). MEASUREMENTS: The following were measured: IBAT volume and weight; unilocular and multilocular brown adipocyte content; preadipocyte number; multilocular cell mitochondrial area; cristae length and density per mitochondrion, and immunoreactivity for the brown adipose tissue specific uncoupling protein (UCP). RESULTS: Following cold acclimation, IBAT increased significantly in weight, volume, relative mass and number of multilocular adipocytes (170%). The number of unilocular adipocytes did not vary significantly. Multilocular adipocytes of both cold-acclimated rats and controls expressed the uncoupling protein, but in the experimental group cristae length and density per mitochondrion were significantly higher. Multilocular adipocyte precursors were observed in only one cold-acclimated rat but not in controls. CONCLUSION: The response of brown adipose tissue of old rats to chronic cold stimulus is similar to that observed in young and adult rats. Cold acclimation induces brown adipocyte recruitment: their number increases significantly, they test UCP-positive and their mitochondria are significantly more active than in controls. On the other hand, the number of unilocular adipocytes is not significantly affected, which may serve to improve the utilization of the heat produced by thermogenesis.

Brown adipocyte precursor cells: a morphological study.

The origin of brown adipocyte precursor cells is to date unknown. Some authors believe they arise from vascular cells, others from interstitial cells. The purpose of the present ultrastructural study was to find markers in rat fetal and perinatal adipose tissue that can be used to identify brown adipose precursor cells. The study was carried out on the interscapular brown adipose tissue of fetal (fetuses of 19 and 21 days) and perinatal rats (pups of 4 and 12 hours and of 1, 3, 5, 7, 9, 11, 13, and 15 days). The analysis focused on stem cells and showed the characteristic presence of typical mitochondria which make their identification as brown adipocyte precursor cells inequivocal. These cells were frequently observed in a pericytic position. Also some endothelial cells were characterised by typical mitochondria and abundant glycogen. These data seem to support the hypothesis that brown adipocytes originate from vascular cells.

Quantitative evaluations of gap junctions in old rat brown adipose tissue after cold acclimation: a freeze-fracture and ultra-structural study.

The morphological and functional modifications of brown adipose tissue (BAT), the tissue responsible for non-shivering thermogenesis, are well established during the phases of active stimulation (i.e. neonatal period and cold acclimation) in young animals. The 'active' brown adipocytes are filled with numerous small lipid vacuoles and large mitochondria packed with cristae rich in the protonophore uncoupling protein (UCP), whereas the 'quiescent' cell shows larger, confluent vacuoles and smaller mitochondria with rarefied cristae poor of the uncoupling protein. It is well known from literature that also gap junctions (gjs), responsible for the electrical coupling among adjacent adipocytes, modify their size following the physiological stimulus in young animals. This is in agreement with the morphology of the functionally active brown adipocyte, i.e. the multilocular, UCP-positive cell. Although the presence of the BAT in old animals is well documented, less is known about its reactivity to physiological stimuli. The present work demonstrates that after cold acclimation brown adipocytes of old rats (2 years) change their ultrastructure in a similar way as in young rats. A quantitative analysis of gap junction areas on replicas obtained by the freeze fracture technique, showed that gj increase in size (mean area 53.2 vs 110.4 x 10(-3) microns2, p = 0.003). All these morphological modifications are quite similar to those observed in BAT of young and young adult rats, supporting the hypothesis of a physiological role of brown adipose tissue at every age.

Electron spectroscopic imaging of secretory granules in human eccrine sweat glands.

A study of human eccrine sweat glands by electron spectroscopic imaging has been performed. A high nitrogen content in secretory granules of the dark mucous cells has been found while mucous cells in the digestive or respiratory systems did not contain nitrogen detectable in our experimental conditions. High concentrations of nitrogen were found in zymogenic granules and in the core of the granules in the eosinophilic leucocytes. Our findings seem to suggest that the granules of the dark secretory cells are composed not only of mucoid substances but contain also high concentrations of proteins. The descriptive term "granulated cells" seems to be more correct than "mucous cells" to indicate these elements.

S-100 protein in rat brown adipose tissue under different functional conditions: a morphological, immunocytochemical, and immunochemical study.

The brown adipose tissue (BAT) is responsible for nonshivering thermogenesis, exhibiting changes in cell morphology related to the functional conditions. In stimulated BAT (neonatal period, cold acclimation) the large majority of adipocytes become multilocular and active, while in inactive BAT (warm acclimation) most cells are pauci- or unilocular and inactive, very similar to white adipocytes. It is well known that white adipocytes are sites of concentration of S-100, a calcium-binding protein originally isolated from the nervous system and later detected also in nonneural cell types, whereas data on the possible presence of this protein in BAT are lacking. The present study used morphological, immunocytochemical, and immunochemical methods to investigate the presence of S-100 protein in BAT under different functional conditions. We found that S-100 was present in both stimulated and inactive BAT and that is was expressed in significantly higher quantities in the latter than in the former. The multilocular cells were always negative (in both active and inactive tissue), whereas the pauci- and unilocular cells were always S-100-positive under both functional conditions. These data suggest that only pauci- and unilocular brown adipocytes express S-100 protein, thus manifesting a possible relationship between S-100 and cell morphology.