Biomedical subjects

S Fasulo

Publications and source records attributed to S Fasulo.

At least 19 recordsLinked to original sources

PubMed2002

Immunohistochemical investigation of the nitrergic system in the taste organ of the frog, Rana esculenta.

We have studied by immunocytochemistry, the taste discs of the frog, Rana esculenta, with the aim of providing morphological and neurochemical data on the nitrergic system and of assessing the eventual presence of intrinsic neurons associated with the gustatory organs. In taste discs, antibodies against neuronal nitric oxide synthase (nNOS) revealed a positive immunoreaction in the taste receptor cell bodies and processes. The basal cells were also stained. All the fungiform papillae contained intragemmal nerve fibers showing nNOS immunoreactivity; these fiber were mainly located in the basal plexus. Immunoreactive nerve fibers were also visible at the periphery of the papilla-contacting ciliate cells, which form a ring around the taste disc. In conclusion, the findings obtained in this study suggest that the occurrence of nNOS-immunoreactivity in basal cells, taste cells and nerves might reflect a role for nitric oxide in taste mechanisms of Amphibia. The results may also sustain the physiological implication of NO as a molecule involved in the local target function of maintaining the taste bud mucosal integrity and in regulating the blood flow to the epithelium.

Animals↗

PubMed2000

Mitochondria-rich cells in anuran amphibia: chloride conductance and regional distribution over the body surface.

The distribution and density (D(mrc)) of mitochondria-rich cells (MR cells) in skin epithelium, were determined over the whole body surface in nine species of anuran Amphibia that live in a variety of habitats. It was found that the more terrestrial species (beginning with Hyla arborea) have a higher density of MR cells in their pelvic region. In the skin of aquatic (Xenopus laevis) or fossorial (Pelobates syriacus) species, D(mrc) is evenly distributed over the whole body surface. In dorsal skin pieces of H. arborea that lack detectable MR cells, transepithelial voltage activation did not induce Cl(-) conductance as it did in ventral pieces. Skins from Bufo viridis and X. laevis, both have MR cells in their skin, differ markedly in their biophysical properties: a Cl(-) specific current conductance is predominant in the skin epithelium of B. viridis, and is absent in X. laevis. In the latter, anionic conductance is due to glandular secretion. The biophysical properties cannot therefore be related solely to the presence or density of MR cells. Mitochondria-rich cells are sites of Cl(-) conductance across the skin of those amphibians that show this property, but must have different function(s) in other species. It is suggested that the specific zonal distribution of MR cells in the species that were examined in this study could be due to ion exchange activity and water conservation in more terrestrial environments.

Animals↗

PubMed1999

Lectin binding patterns in amphibian skin epithelium.

Seven lectins (PNA, DBA, WGA, UEA-I, RCA, SBA, Con A) were used to localize glycoconjugates in the skin of 10 species of Amphibia, 7 anurans (Bufo marinus, Bufo bufo, Rana ridibunda, Rana pipiens, Hyla arborea, Pelobates syriacus and Xenopus laevis) and 3 urodeles (Salamandra salamandra, Triturus vulgaris and Ambystoma mexicanum). It was found that every lectin has a specific binding pattern in the skin of each species. No common pattern could be established, either among frogs or toads, nor for a particular lectin. Each lectin bound specifically and selectively to a particular epithelial component, which differed from one species to the other. A number of lectins showed selective binding to mitochondria-rich cells, but, again, a pattern in positivity could not be found. It is concluded that lectin histochemistry does correlate with cellular function. Our data can be applied in studies of epithelium and skin development, and of changes that occur during adaptation to the environment by amphibian species.

Animals↗

PubMed1999

Neuronal nitric oxide synthase (nNOS) expression in the epithelial neuroendocrine cell system and nerve fibers in the gill of the catfish, Heteropneustes fossilis.

We studied immunohistochemically the localization of neuronal nitric oxide synthase (nNOS) in gills of an Indian catfish species, Heteropneustes fossilis. It is shown that most of the epithelial neuroendocrine cells that are present in gill filaments and lamellae stained positively. Co-localization of nNOS and endothelin was also shown in neuroendocrine cells. A dense plexus of nNOS-containing nerve fibers was present beneath the gill epithelium, associated with efferent filament arteries and the basal side of neuroendocrine cells. nNOS immunopositive neurons were not found in gill areas. nNOS immunopositive neuroendocrine cells appeared to differ from neuroepithelial cells in gills of various teleost species, which are considered as oxygen-sensitive receptors and are present in the distal halves of gill filaments. Other types of neuroendocrine cells have been identified previously in other areas of gills using antibodies to serotonin and endothelin peptides. These cell types are likely to be involved in chemical regulation of the physiology of gill cells. In relation to the function of the other cell types, our data on nNOS localization suggest that NO is a wide-spread transmitter in the gill of the Indian catfish. It may play a role both in the local regulation of vascular tone and in inhibitory innervation of the gill.

Animals↗

PubMed1997

Paraneurons in the gills and airways of fishes.

This chapter describes the distributional patterns of the neuroendocrine cells in the respiratory surfaces of fishes and their bioactive secretions which are compared with similar elements in higher vertebrates. The neuroendocrine cells in the airways of fishes differentiate as solitary and clustered cells, but the clusters are not converted into neuroepithelial bodies which are reported in terrestrial vertebrates. The dipnoan fish Protopterus has innervated neuroendocrine cells in the pneumatic duct region. In Polypterus and Amia the lungs have neuroendocrine cells that are apparently not innervated. Two types of neuroendocrine cells are found in the gill of teleost fishes. These cells are very different by their location, structure and immunohistochemistry. Advanced studies on functional morphology of neuroendocrine cells in fish airways are still necessary to increase our understanding of their multifunctional role in the gill area.

Animals↗

PubMed1997

Lectin binding pattern and band 3 localization in toad skin epithelium and the effect of salt acclimation.

Seven lectins were employed to localize glycoconjugates in the skin of a toad (Bufo viridis). Each of the lectins exhibited a particular, specific and selective binding pattern. Peanut lectin (PNA) and WGA bound to mitochondria-rich (MR) cells, but WGA bound also abundantly, in the dermis. Band 3-like protein, as indicated by the reaction with polyclonal anti band 3 antibody, was localized exclusively in MR cells. Ionic acclimation (200 mmol/L NaCl, or 50 mmol/L KCl) affected profoundly the binding pattern of the lectins. High NaCl acclimation resulted also in diminishing anti band 3 antibody binding, whereas in skins of KCl-acclimated toads the staining remained similar to the control. The binding of WGA but not PNA, corresponded with the same cells that stained with anti band 3 antibody. PNA in concentration of > 10 micrograms/mL reduced reversibly, both the resting and activated Cl- conductance by 25-30%. Based on differential binding of band 3, WGA and PNA, these observations provide conclusive verification of the presence of at least two populations of MR cells in the toad skin epithelium. It is suggested that the PNA positive MR cells may correspond to a beta-type MR cell. The information can be used to study molecular mechanisms that are involved in ionic acclimation.

Adaptation, Physiological↗

PubMed1996

Immunocytochemical detection of islet hormones in the digestive system of Protopterus annectens.

The presence, distribution, and interrelationships of the four typical pancreatic islet hormones were investigated in the digestive system of Protopterus annectens by single and double immunohistochemical methods. Insulin-, glucagon-, and somatostatin-immunoreactive (IR) elements were detected in both the pancreas and the gut. Pancreatic polypeptide (PP)-IR endocrine cells were always present in the gut, but were only present in the pancreas of a few specimens. Some of the latter cells also seemed to react with glucagon antiserum. In the pancreas the immunopositive cells were organized into islets of different sizes, and their organizations were studied by the double immunohistochemical techniques. In the few large islets insulin-IR cells were present in the central zone, glucagon- and PP-IR cells at the periphery, and somatostatin-IR cells intermingled with both the peripheral and the central endocrine cells. In the smaller islets, the number and the staining intensity of glucagon- and PP-IR endocrine cells varied markedly. In the gut, insulin-, somatostatin-, and PP-IR cells were of the open type; glucagon-containing cells were very few and had no luminal contact. They were differently distributed along the intestinal epithelium. Somatostatin-IR nerve fibers and somatostatin-IR neuron cell bodies were also observed in the intestinal wall. The organization of pancreatic endocrine cells in P. annectens is similar to that observed in the majority of teleosts even if a different topographical association can be found. Furthermore, islets of different sizes seem to display a different metabolic turnover, and the detection of pancreatic PP-immunoreactivity varied according to the specimens utilized. In the intestinal portion insulin-IR cells, in addition to PP-, glucagon- and somatostatin-IR cells are present: this suggests that intestinal insulin-like immunoreactivity may be more widespread than previously supposed.

Animals↗

PubMed1996

Localization of immunoreactive endothelin in the neuroendocrine cells of fish gill.

Immunohistochemical tests have demonstrated for the first time the presence of endothelins in the neuroendocrine cells of fish gill. We have sought co-localization of endothelins with serotonin and neuropeptides which are regarded as neuroendocrine markers of pulmonary diffuse neuroendocrine systems in higher vertebrates. Regarding their endocrine and paracrine activities in mammals, endothelins are considered as peptide hormones and growth factors regulating respiratory function. The roles of endothelins in the gill await investigation based on the multifunctional organization of this organ.

Amino Acid Sequence↗

PubMed1996

Glycoconjugate expression changes during Rana dalmatina early development.

Glycoconjugates are generally involved in cell adhesion and morphogenetic movements. To investigate their distribution and expression changes during amphibian development, several FITC-or HRP-labeled lectins were used in Rana dalmatina embryos and larvae. During gastrulation, WGA, ConA, HPA, GSA-I, PNA and RCA-I labeled either the envelopes on the perivitelline space-contained substances, while ectodermal cells and/or extracellular matrix were mainly labeled by WGA, GSA-I, DBA and LTA. In these structures fibronectin-like molecules were also found. ConA, HPA, RCA-I, SBA also labeled ectoderm, but with lower affinity. At larval stages, ectodermal derivatives, such as larval skin, central nervous system, eye and ear, were also strongly labeled by WGA, DBA and LTA, while the affinity to ConA, HPA, GSA-I, SBA, appeared less visible; the affinity sites to RCA-I and PNA were totally lacking. Fibronectin-like immunoreactivity was hardly present at the larval stages. These results point out that glycoconjugate expression changes in cell surface and in extracellular matrix might be developmentally regulated. For this reason the different glycoconjugates seem to play stage-specific roles in early development.

Animals↗

PubMed1995

Enkephalin immunoreactivity in the paraneurons of the tiger salamander (Ambystoma tigrinum) tongue.

Immunohistochemical tests have demonstrated the presence of leu-5-enkephalin and other bioactive compounds (serotonin and neuron-specific enolase) in the basal cells of lingual taste buds in Ambystoma tigrinum; there was also a weak reaction for met-5-enkephalin. Similar reactions were obtained from particular cells dispersed within the lingual epithelium, which are provisionally identified as Merkel cells.

Ambystoma↗

PubMed1995

Neuroendocrine cells in the gills of the bowfin Amia calva. An ultrastructural and immunocytochemical study.

Neuroendocrine (NE) cells were localized by electron microscopy and immunocytochemistry in the gill epithelium of bowfin Amia calva. The NE cells are dispersed in whole epithelium of the gill as solitary cells without intraepithelial innervation. All the observed NE cells do not reach the surface of the epithelium. The NE cells are characterized by a large nucleus with patches of condensed chromatin, numerous mitochondria, a well developed Golgi apparatus and a few dense core vesicles of various size scattered in the cytoplasm. Dense core vesicles range from 100 to 560 nm in diameter, while a clear space between the electron dense core ant the limiting membrane ranges from 20 to 240 nm. Immunocytochemical observations reveal the presence of general neuroendocrine markers such as neuro-specific enolase and bioactive substances: serotonin, leu-enkephalin and met-enkephalin. we demonstrated the presence of endothelin - for the first time in fish - and suggested a local paracrine role for the NE cells. Some ultrastructural aspects and the immunocytochemical characteristics of NE cells of bowfin gills are common with those encountered in such cells of other lower vertebrate species.

Animals↗

PubMed1995

Distribution patterns of cytokeratins in epidermis and horny teeth of the adult sea lamprey, Petromyzon marinus.

An immunohistochemical characterization of cytokeratins in the skin tissues of the sea lamprey, Petromyzon Marinus was performed using a panel of monoclonal antibodies. Cytokeratins typical for simple epithelia have been detected in the epithelial cells, with a 8/18 pair expression. Granular cells and skein cells showed a labelling of cytokeratins 7, 8, 18 and 19, that is observed also in the non-keratinized layers of the horny teeth. Similar cytokeratins occur in the outermost cell layers of the epidermis; cytokeratin 19 shows a comparatively weaker reaction. These results suggest that the cytokeratin patterns in the above types of cells of adult epidermis are quite different from those in ammocoetes where the expression of cell specific cytokeratins may be correlated with specific programs of epidermal differentiation.

Age Factors↗

PubMed1995

Cytokeratin type distribution in the skin and gill epithelia of the Indian freshwater catfish, Heteropneustes fossilis as detected by immunohistochemistry.

Based on the general cross-reactivity of the cytokeratins in vertebrates, we describe the immunoreactivity for some mammalian cytokeratins of both the epidermis and gill of H. fossilis. The following monoclonal antibodies, commercially supplied, were tested: K8.13, KL1, AE1 and AE3, which have a wide spectrum of specificity, and LDS-68, M 20, K8.60, KS-B17.2, K4.62, which are more narrowly specific. The reaction of the epithelial cells of the skin to K8.13 was negative in the basal layer, weakly positive in the layers above but strongly positive in some cells of the superficial layer. KL1 was negative in the basal layer, positive in the outer layers. AE1 was strongly positive in the basal layer, negative in the superficial cells. AE3 gave a general but weak reaction in the epithelial cells. K8.60 was negative for the epithelial cells, but reacted positively in the club cells. Club cells also reacted to K8.13 and AE1, and were strongly positive to KL1 and AE3. Goblet mucous cells were negative to all antibodies tested. In the gills, K8.13 labelled cells of both filament and lamellar epithelia. The reaction to AE3 was similar but less intense. KL1 was positive in the basal layer of the filament epithelium but not elsewhere, and K8.60 was negative throughout. AE1 and KS- B17.2 specifically labelled small cells scattered in the filament and lamellar epithelia, which are tentatively identified as neuroendocrine cells.

Animals↗

PubMed1994

Distribution patterns of the paraneuronal endocrine cells in the skin, gills and the airways of fishes as determined by immunohistochemical and histological methods.

The neuro-endocrine cells of fish skin and respiratory surfaces, and their bioactive secretion as far as is known, are reviewed, and compared with similar elements in tetrapods, particularly amphibians. In the skin of teleost fish, immunohistochemistry has shown that Merkel cells react for serotonin, neuron-specific enolase and enkephalins. The pharmacology is not established in dipnoans or lampreys. In some teleosts, neuromasts react for substance P and leu-enkephalins; substance P is also reported from some ampullary organs (electroreceptors). Taste buds of teleosts may react for enkephalin and substance P. Basal cells of taste buds react for serotonin and neuron-specific enolase. Some unicellular skin glands of teleosts express bioactive compounds, including serotonin and some peptides; this ectopic expression is paralleled in amphibian skin glands. The dipnoan Protopterus has innervated pulmonary neuro-endocrine cells in the pneumatic duct region with dense-cored vesicles. In Polypterus and Amia the lungs have serotonin-positive neuro-endocrine cells that are apparently not innervated. In fish gills, a closed type of neuro-endocrine cell reacts for serotonin, an open type for enkephalins and some calcium-binding proteins (calbindin, calmodulin and S-100 protein). The functions of neuro-endocrine cells in fishes await investigation, but it is assumed they are regulatory.

Animals↗

PubMed1993

Distribution of immunoreactive Tamm-Horsfall protein in various species in the vertebrate classes.

A sheep antibody to human Tamm-Horsfall protein, the major protein in normal urine, was used in an immunohistological study of organs of 48 species of vertebrate animals, representing the classes Mammalia, Aves, Reptilia, Amphibia, Osteichthyes and Chondrichthyes. Immunoreactivity was shown in the thick limb of the loop of Henle in the kidney of mammals, but there was no reactivity with tissues of birds or reptiles. Superficial layers of the skin of several amphibians and fish, superficial layers of the oral mucosa and gills of fish, and the distal tubules of the kidney of some amphibians, reacted with the antibody. Immunoreactivity with mammalian kidney was removed by passage of the antibody down an immunoadsorption column coated with human Tamm-Horsfall protein, and amphibian immunoreactivity was removed by incubation of the antibody with material prepared from frogs in the same way as Tamm-Horsfall protein. These findings suggest that immunoreactive Tamm-Horsfall protein appeared early in vertebrate phylogeny, initially in skin and gills and later in kidney, and that although conserved in evolution, it shows antigenic differences between amphibians and mammals. Its distribution is consistent with the hypothesis that is acts as a waterproofing agent.

Amphibians↗

PubMed1993

Ectopic expression of bioactive peptides and serotonin in the sacciform gland cells of teleost skin.

Immunohistochemical methods identified serotonin, and the peptides bombesin and caerulein, in the skin of the teleosts Lepadogaster candollei and Mastacembelus erytrotaenia. In both species, the secretory content of epidermal sacciform cells reacted positively for all three substances. These results are compared with studies on the skin glands of amphibians, which also contain multiple active compounds, and on various neuroendocrine cells of fish. The precise functions of the secretions are not known.

Animals↗

PubMed1993

Immunoreactive endocrine cells and nerve elements in the gut of the Italian cave salamander.

The presence and distribution of eleven different types of immunoreactive endocrine cells and nine types of immunoreactive nerve elements were immunohistochemically identified in the gut and pancreas of the italian cave salamander, Hydromantes ambrosii. The majority of gastrointestinal endocrine cells were of open-type, often presenting basal cytoplasmic processes. Gastrin- and substance P-immunoreactive cells in the fundus and bombesin-immunoreactive cells in the intestinal portion were instead of closed type. Immunoreactive nerve fibres were particularly numerous in the muscular layers and blood vessel wall; bombesin- and substance P-immunoreactive nerve fibres were also abundant beneath gastro-intestinal epithelium. Besides substance P-, caerulein- and cholecystokinin-immunoreactive nerve fibres, all the other immunopositive nerve fibres seemed to be of intrinsic types. By the use of four different gastrin/cholecystokinin antisera three variously distributed subpopulations of endocrine cells and nerve elements were detected. Most of the pancreatic endocrine cells were organised in chord-like islets, polarized in the direction of blood vessels. A sparse network of bombesin-immunoreactive fibres was also found in the pancreas. The distribution of bombesin- and of the gastrin/cholecystokinin-immunoreactive material in the stomach and the presence of closed type endocrine cells indicate a more evoluted organization of the gastroenteropancreatic neuroendocrine system thus confirming the position of Hydromantes ambrosii among the higher urodeles.

Animals↗

PubMed1992

Localization of calbindin D28K-like immunoreactivity in fish gill: a light microscopic and immunoelectron histochemical study.

The presence of calbindin D28K in fish (Heteropneustes fossilis) gill was studied by use of specific antibodies raised against chick duodenal 28 kDa calbindin in immunoperoxidase and electron-microscopic labelling experiments. Immunoreactivity for calbindin D28K, which has been observed in the intestine of a number of avian and mammalian species, is reported for the first time in the gill. It was primarily located in neuroendocrine (NE) cells. Some immunoreactivity was also located in the glycocalyx of the non-endocrine cells, i.e., the pavement cells, which have ultrastructural characteristics quite different from those of endocrine cells. The calbindin-immunopositive NE cells were ascertained in both gill filamental and lamellar epithelium. All the NE cells contained secretory granules as the most distinctive feature of these cells. Ultrastructurally, two types of NE cells were distinguished according to the morphology of their secretory granules. The calbindin immunoreactivity in the NE cells was stimulated when the calcium concentration of the ambient water was reduced. The present findings suggest that NE cells exert some as yet unidentified function related to calcium-mediated processes involving the expression of calbindin.

Animals↗