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Biomedical subjects

T Renda

Publications and source records attributed to T Renda.

At least 37 records · Page 2Linked to original sources
PubMed1992

An immunohistochemical study on neurons and paraneurons of the pre- and post-natal chicken lung.

The indirect immunoperoxidase (PAP) method was used on chicken lung specimens from embryos ranging in age from 6 days to hatching, chicks and adult chickens of up to 6 months. The ontogenesis and distribution of neurons and paraneurons containing immunoreactivities for serotonin (5HT), bombesin, vasoactive intestinal polypeptide (VIP), substance P (SP) and galanin were investigated. Serotonin-immunoreactive paraneurons were first detected in the pulmonary mesenchyma of 8-day-old embryos, while in the 12-day-old embryos the following neurons and paraneurons were first detected in their respective locations: serotonin-immunoreactive paraneurons in the bronchial epithelium; VIP- and galanin-immunoreactive ganglionic cells and SP-immunoreactive nerve fibres in the intrapulmonary ganglia. At hatching, serotonin-immunoreactive paraneurons in the epithelium of the air capillaries and air sacs, and bombesin-immunoreactive paraneurons in the epithelium of the primary bronchus, VIP-, galanin- and SP-immunoreactive nerve fibres in the lamina propria of the primary and secondary bronchi and in the pulmonary septa could also be shown. Some serotonin-immunoreactive small paraneurons were also found in the intrapulmonary ganglia. In the adult specimens, VIP-, galanin- and SP-immunoreactive nerve fibre networks were observed throughout the primary bronchus wall and in the lung septa. In intrapulmonary ganglia, VIP- and galanin-immunoreactive neurons and serotonin-immunoreactive small paraneurons could be more numerously demonstrated. Moreover, bombesin paraneurons occurred in the epithelium of primary and secondary bronchi, and serotonin-immunoreactive paraneurons were found in the epithelia of the bronchi and air sacs and in some pluricellular bodies in the lamina propria of the air sac ostia.

Animals↗
PubMed1992

Modification of lectin binding in rat gut mucosa during experimental cholestasis.

Glycoconjugate distribution on rat gut mucosa has been studied by using peroxidase-labelled lectins (Lotus tetragonolobus, Dolichos biflorus, Arachis hypogaea and Glycine max) after surgical interruption of the common bile duct. Specimens from cholestatic rats were compared with sham-operated (simple laparotomy) and normal controls to determine which of the observed modifications could be due either to the operation itself or to the cholestasis. Most of the modifications occurred in the duodenum. The operation itself modified some binding properties. Lotus tetragonolobus binding extended both in cholestatic and in sham-operated rats, but returned to normal levels earlier in sham-operated than in cholestatic rats. Conversely, cholestasis induced (1) almost total loss of Arachis hypogaea binding in the Golgi zone of superficial duodenal goblet cells; (2) an increase at the 14th postoperative day of Dolichos biflorus binding in the cytoplasmic calyx of goblet cells which then diminished up until the 28th day; and (3) an increase of Glycine max binding in the Golgi zone of goblet cells.

Animals↗
PubMed1989

Brain-gut-skin peptides: an update overview.

The authors present an overview of the main amphibian peptide families mainly derived from the skin and mostly discovered by Erspamer and his associates. The studies of the peptides do not only promote the understanding of their chemical, metabolical and physiological features of those molecules in amphibians, but also contribute to progress in our knowledge of the corresponding mammalian counterparts. Particular reference is made on sauvagine, tachykinin, bombesin and dermorphin families, offering new data mostly from personal contributions to this field.

Amphibians↗
PubMed1989

Ontogenesis of endocrine cells in the chicken intestine: an immunohistochemical study.

The authors report the time of appearance, morphology and topographic distribution of gastrin/cholecystochinin- (G/CCK-), somatostatin- (SRIF-), neurotensin- (NT-), motilin- (MO-) and substance P-like immunoreactive (SP-LI) elements during embryonic and postnatal development, in ileum, caeca and colon of chick embryos (from 8 days of incubation to hatching), newborn chicks (up to 15-days old) and adult chickens. In the ileum, G/CCK-LI and SP-LI cells appeared on day 11, the others on about day 13. In the caeca the first cells of all types were seen from about day 17. In the colon, NT-LI cells appeared early, on day 9, SP-LI and occasional SRIF-LI cells from day 13 on and MO-LI and G/CCK-LI only from day 17. In the ileum all the cells studied were present, in the caeca and colon they were extremely scarce, apart from NT-LI cells which were more numerous. In the prenatal stages, SP-LI was found only in epithelial cells; after hatching, it was also present in metasympathetic nerve elements.

Aging↗
PubMed1989

5-HT-like immunoreactive cells in chicken intestine: ontogenesis, morphology and topography.

The indirect immunoperoxidase method was used to describe time of appearance, morphology and topography of 5-hydroxy- tryptamine-like immunoreactive (5-HT-LI) cells in the gut of chick embryos, newborn and adult chickens. The earliest cells were seen in the ileum at 11 days, in the caeca at 14 and in the colon at 9 days. At first appearance they were ovoid or pyramidal but later became more irregular because of the numerous apical and basal processes. The peak of cell concentration at hatching, was in the ileal samples, whereas in the colon these cells were also abundant in adults both throughout the villi and the glands. In sections of adult ileum, on the contrary, they could be found mainly in the glands.

Animals↗
PubMed1988

Sauvagine/urotensin I-like immunoreactivity in the brain of the dogfish, Scyliorhinus canicula.

The localization of a sauvagine (SV)/urotensin I (UI)-like material in the brain of the dogfish, Scyliorhinus canicula, was studied by immunohistochemical techniques, employing an antiserum raised in rabbit against synthetic SV which widely cross-reacts with UI. Positive cell bodies and nerve fibers were identified in the dorsocaudal hypothalamic region of the tuberculum posterius, in the nucleus sacci vasculosi and nucleus tuberculi posterioris. A dense network of immunoreactive axons was shown in the whole tuberculum posterius. These findings support the view that SV/UI-like peptides may be involved in neuromodulatory functions throughout the brain of cartilaginous fish.

Amphibian Proteins↗
PubMed1988

Comparative chemical anatomy of the brain: concepts and methods.

The study of neuropeptides represents an appropriate playground for comparative and evolutionary research. Comparative analysis can give insight into the conservative pattern of intercellular transmission molecules, possibly bound both to some evolutionary antiquity and to cellular constraints. In the same time it can teach us how modulation has occurred at molecular, cellular, multicellular levels in order to give the species-specific functional organization. Using some examples from vertebrate central neurons system (CNS) immunocytochemical analyses, the results so far obtained suggest the rise of a new comparative chemical neuroanatomy. The rationale of "what" and "why" we are comparing is, however, needed in order to understand constancy, heterogeneity or else trends toward complexity in the distribution of neuropeptides.

Anatomy, Comparative↗
PubMed1986

Ontogenesis of 5-hydroxytryptamine-like immunoreactive cells and their relationship with bombesin in chicken proventriculus.

By using a double-stain immunohistochemical procedure, the Aa. studied the onset, the behaviour and the possible interrelationship between the 5-HT-like and bombesin-like immunoreactive cells during the ontogenesis of chicken proventriculus and in adult animals. The 5-HT-like immunoreactive cells become evident from the 8th day of incubation and they reach their peak around the 16th day, then markedly decrease at hatching. In adult animal these cells are always present, but are not so numerous. Between the 14th and the 18th day many double-stained cells scattered among other only 5-HT or bombesin-like immunoreactive cells are present. They can also be observed in adults, but only occasionally.

Animals↗
PubMed1986

Immunohistochemical studies on the ontogenesis of some endocrine cells in the chicken antrum and duodenum.

The time of appearance, morphology and topographic distribution of gastrin/CCK-, somatostatin-, 5HT-, and bombesin-like immunoreactive cells during embryonic and postnatal development were studied in chicken antrum and duodenum with immunohistochemical methods. Gastrin/CCK-like cells appeared on or about the 11th day in the antrum and duodenum, somatostatin-like cells around the 12th day in the antrum and the 11th day in the duodenum, bombesin-like cells appeared only in the antrum and only at hatching. In the early stages of development all the immunoreactive cells were localized in the surface epithelium, descending deeper into the glands as these form, although some cells could always be seen in the surface epithelium. Around the 17th day the number of gastrin/CCK-like cells and somatostatin-like cells in the antrum increases, while 5HT-like already become more numerous in the duodenum from the 13th day onwards. Two territories were recognized in the antrum of the adult: the first was near the duodenum where gastrin/CCK-like and somatostatin-like cells, often in close contact, were very numerous; the other territory was near the gizzard where bombesin-like cells were more numerous. Both regions contained 5HT-like cells in smaller number. In adult duodenum, 5HT-like cells were the most numerous, while somatostatin-like cells and gastrin/CCK-like cells, found in more superficial locations, were more scanty.

Animals↗
PubMed1985

Tryptophyllin-like immunoreactivity in rat adenohypophysis.

A new amphibian peptide family has been isolated from the skin of a South American frog Phyllomedusa rhodei and named Tryptophyllins (TPH) because of their content in tryptophyl residue. Using an antiserum against one of these peptides, namely the pentapeptide Met-5-TPH-5-amide (PHE-PRO-PRO-TRP-MET-NH2), we observed the presence of a set of immunoreactive cells in rat adenohypophysis. These cells were far more numerous in pregnant than in normal male and non-pregnant female rats. Dual immunostainings demonstrated that, with some exceptions, almost all the TPH-like immunoreactive cells were gonadotrophs. At electron microscope both types of gonadotroph cells displayed immunoreactivity and the gold particles strongly labelled both types of granules. The Aa. advance the hypothesis that, besides the hormones themselves, the secretory granules might contain some TPH-like sequence.

Animals↗
PubMed1985

Active peptides from amphibian skin are also amphibian neuropeptides.

Immunohistochemical data on several newt brain areas showed a heterogeneous system of neuronal elements, immunopositive for antisera specifically directed to different antigenic determinants of tachykinin molecules. Acid extracts of newt brain areas were immunopositive for substance P with an antibody specific for the COOH-terminal (tachykinin determinant) and exhibits an elution profile by gel filtration characteristic to substance P. Bombesin-like immunoreactivity was demonstrable both by immunohistochemistry (fibers and cell bodies in forebrain and hypothalamic areas) and by radioimmunoassay, using an antiserum specific for the mid-region of the molecule. This immunoreactivity was separated into two peaks by gel filtration chromatography. Sauvagine-like material was detected by immunohistochemistry in newt hypothalamus as a loose preoptic cell system and as a thin fiber layer in the outer zone of the median eminence. Double staining procedures demonstrate that sauvagine and CRF are spatially closely related but separable in both the preoptic area and in the median eminence. This data on the presence of several amphibian skin peptides in the CNS of the newt suggests their possible role as neuropeptide.

Amphibian Proteins↗
PubMed1984

Ontogenesis of bombesin-like immunoreactive cells in the chicken proventriculus.

The distribution and morphological behaviour of bombesin like immunoreactive cells in the proventriculus of chick embryos, newborns and adults were investigated by indirect immunoperoxidase procedure. The first immunoreactive cells appear around the 11th day of incubation. Initially few, they increase progressively to reach a peak around the 18th day. Throughout the embryonic period almost all immunoreactive cells are column-shaped, display a typical "open" behaviour, and are situated among other superficial lining epithelial cells. Around hatching time, these "open" cells suddenly decrease in number while another immunoreactive "closed" cell type becomes more evident in a deeper location. In newborns and adults, the majority of immunoreactive cells are oval shaped and are characteristically situated near the neck of lobular glands; they seem to display a "closed" behaviour. The results demonstrate two different kinds of peptide-containing cells which probably exert different functions. During the embryonic period, in fact, they resemble a chemioreceptor, but in postnatal life they appear as a paracrine/endocrine elements.

Animals↗
PubMed1982

Sauvagine-like immunoreactivity in the bony fish urophysis and caudal neurosecretory system.

Immunoperoxidase methods were used to reveal Sauvagine-Like immunoreactivity (SVLI) in the urophysis and whole caudal neurosecretory system of fresh water fish Tinca tinca and Salmo gairdneri L. Both Dahlgren cell cytoplasm and axons, which reach the urophysis, were filled with SVLI granules. The urophysis shows: a) in the medullary zone, several SVLI Dahlgren cells and a thick network of SVLI axons; b) in the cortical zone, a series of complicated neurohemal knots where SVLI axonal endings surround and penetrate the capillary and glial cell networks. An individual variability and the possibility of a release of SVLI material into the cerebrospinal fluid were also demonstrated. These observations further suggest that, besides the biological effects, sauvagine and the urophysial substance urotensin I, may also have a similar structure.

Amphibian Proteins↗
PubMed1981

The brain-gut-skin triangle: new peptides.

New data on tachykinins and bombesins are displayed and the present situation of research on the novel amphibian skin peptides sauvagine and dermorphin is illustrated. The potent stimulant effect of sauvagine on ACTH and beta-endorphin release has been confirmed both in vivo and on columns of isolated and dispersed rat pituitary cells, and similarly the potent inhibitory effect on PRL and GH release, both in the rat and man. Particular emphasis is laid on the occurrence of sauvagine-like immunoreactivity in fish urophysis and in amphibian nervous structures, including the retina. It is suggested that the long-searched corticotropin releasing factor and PRL release-inhibiting factor may be a sauvagine-like peptide. Dermorphin, in its turn, has been found to cause, by intracerebroventricular injection, not only analgesia and catalepsy, but also conspicuous EEG and behavioral changes in the rabbit and chick, as well as a sharp reduction in gastric emptying time and gastric acid output in the rat, together with marked stimulation of PRL release.

Adrenocorticotropic Hormone↗
PubMed1979

Histochemical studies of some hepatic enzyme activities in rat during extrahepatic common bile duct obstruction.

Studies on some enzyme activities as measured histochemically in the ligated common bile duct rat liver are reported. They show principally: an increased GGT reaction in the neoductular cells; a diffusion of the LAP reaction to the neoductuli; an immediate increase and diffusion of the alkaline phosphatase reaction; an increase of G-6-PA and AMPA reactions; an increase, during the first week, of the Phyla activity and a contemporary decrease of the UDPG-GS reaction. No significant changes have been observed in other enzyme activities. By means of some dehydrogenase reactions, morphological evidence that the hepatocytes may be involved in neoductular cells formation was obtained.

Adenosine Monophosphate↗
PubMed1978

Surface coat in steroid-secreting cells of the mouse ovary.

Steroid-secreting cells (luteal, thecal and interstitial cells) of the mouse ovary have been studied with the ruthenium red method to stain the "cell coat". The results showed that a typical cell coat covers the entire surface of the plasma membrane except where the cells are connected by specific cell junctions. Further, particularly heavy concentration of ruthenium-red-reacting material was demonstrated in pericapillary and intercellular spaces. The differences in the thickness of the cell coat and its topographical modifications among different groups of steroidogenic cells may be related not only to intercellular adhesion and interactions but also concerned with a function of control in which the cell permeability is modified in relation with phenomena of cell recognition.

Animals↗