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E Adeghate

Publications and source records attributed to E Adeghate.

At least 73 records · Page 4Linked to original sources
PubMed1997

Immunohistochemical identification of pancreatic hormones, neuropeptides and cytoskeletal proteins in pancreas of the camel (Camelus dromedarius).

The patterns of distribution of insulin (INS), glucagon (GLU), atrial natriuretic peptide (ANP), neuropeptide-Y (NPY), cholecystokinin-octapeptide (CCK-8), neurofilament-200 protein (NF), S-100 protein (S-100), and vimentin (VIM) in the pancreas of the one-humped camel (Camelus dromedarius) were investigated using immunohistochemical techniques. INS-immunoreactive cells were observed in the central and peripheral parts of the islets of Langerhans, but some solitary INS-positive cells were found outside the islets. INS-positive cells constituted 44.26-90.91% [mean +/- standard deviation (std): 67.34 +/- 14.20] of the total number of islet cells. GLU-immunopositive cells were located mainly in the peripheral region of the islets, and they constituted 11.43-44.44% [mean +/- std: 23.54 +/- 8.27] of the total number of islet cells. ANP and CCK-8 immunoreactivity was observed in neurons and perivascular nerves fibers. NPY was identified in pancreatic neurons and in some peripheral and central cells of the islets of Langerhans. VIM immunoreactivity was observed in the endothelial cells of blood vessels and the nerves located in the perivascular, interlobular and periacinar regions. VIM was also detected immunohistochemically in the periductal nerves of the pancreas. NF occurred only in nerves. S-100 was discerned mainly in the nerves of the interlobular connective tissue and in nerves lying close to blood vessels and acinar tissue. It is concluded that INS, GLU, ANP, NPY, CCK-8, NF, S-100, and VIM are well distributed in the pancreas of the camel.

Animals↗
PubMed1997

Interactions of islet hormones with acetylcholine in the isolated rat pancreas.

This study investigates the effects of the islet hormones, insulin (INS), glucagon (GLU) and somatostatin (SOM) on acetylcholine (ACh)-evoked amylase secretion and calcium (Ca2+) mobilization in the isolated rat pancreas. Stimulation of pancreatic segments and acini with either INS, GLU or SOM resulted in small increases of amylase output compared to much large increases in enzyme output with ACh. Combinations of the peptide hormones with ACh resulted in enhanced secretory responses compared to the effects obtained with either ACh or each of the islet hormone alone. Genistein, the tyrosine kinase inhibitor, evoked a decrease in amylase output from pancreatic segments. It had no effect on the ACh evoke secretory response but it markedly inhibited the potentiation of the islet hormones with ACh. In pancreatic acinar cells either INS, GLU or SOM elicited moderate increases in amylase output compared to much larger responses with ACh. Furthermore, the islet hormones failed to potentiate the secretory effect of ACh in pancreatic acini. In fura-2 AM loaded acinar cells both INS and GLU evoked small increases in intracellular free calcium concentration [Ca2+]i compared to a much larger elevation with ACh. Both INS and GLU enhanced the ACh-evoked [Ca2+]i. Genistein elicited a decrease in [Ca2+]i both in the absence and presence of both INS and GLU. It also decreased the rise in [Ca2+]i resulting from the combined presence of ACh with both INS and GLU. SOM had no significant effect on the ACh-induced [Ca2+]i. When genistein was combined with ACh and SOM there was a decrease in [Ca2+]i compared to the response obtained with SOM and ACh alone. The results indicate that both tyrosine kinase and cellular Ca2+ seem to be the intracellular mediators associated with the enhanced secretory responses obtained with a combination of the islet hormones with ACh. Finally, our results using immunohistochemical techniques confirm the presence of INS-, GLU- SOM- and ACh-immunoreactive cells in the endocrine and neural elements of the rat pancreas.

Acetylcholine↗
PubMed1997

Co-existence of leukoderma with features of Dowling-Degos disease: reticulate acropigmentation of Kitamura spectrum in five unrelated patients.

BACKGROUND: The spectrum of Dowling-Degos disease-reticulate acropigmentation of Kitamura (DDD-RAK) is a group of rare autosomal dominant disorders that have in common a unique histological picture of hyperpigmented digitate epidermal 'downgrowths'. Patients with the DDD-RAK spectrum may show hyperpigmented macules and papules, facial pits, breaks in dermatoglyphics and epidermoid cysts. OBSERVATIONS: We examined 5 unrelated patients, 3 females and 2 males (age range 22-35 years), who presented with clinical and histological features of the DDD-RAK spectrum. In addition, the patients presented with hypo- or depigmented macules and papules. Histopathology of the lesions revealed features that were identical to DDD-RAK; there were, however, diminution or absence of pigmentation. Family histories for pigmented lesions and leukoderma were positive in all patients and consistent with autosomal dominant modes of inheritance. CONCLUSION: These 5 cases, together with isolated reports in the literature of achromic lesions with histological features of DDD-RAK, point to the hypothesis that achromic macules and papules may be a feature of the DDD-RAK spectrum.

Acrodermatitis↗
PubMed1997

In vitro amylase release of preserved pancreas: a simple test to assess the viability of pancreatic allograft during preservation in the pigs.

To determine an in vitro marker of viability during pancreatic preservation, 12 pigs underwent total pancreas harvesting, and graft were stored in Euro-Collins or Belzer perfusion solution for up to 24 hours. Amylase concentration of the storage solution was analyzed in regular periods and tissue samples were taken for acridine-orange histochemical evaluation of viability in the same time. In vitro pancreatic amylase release (IU/g pancreas tissue) was calculated from the volume of solution and the weight of graft. A significant increase of amylase release was found in the course of preservation in both media. Comparing amylase release in different solutions we found significant difference between Euro-Collins and Belzer media (4 hours: 6.45 IU/g vs. 2.2 IU/g, 8 hours: 11.5 vs. 3.58, 24 hours: 8.7 vs. 42.8, respectively). Comparison of amylase release with histochemical evaluation of viability showed strict correlation. We concluded that amylase release is a good marker for exocrine tissue destruction as well as viability of preserved pancreas. Our data confirms that Belzer solution is superior in pancreatic preservation. It is suggested that after adaptation into human model in vitro pancreatic amylase release could be a time- and cost-saving, useful method in predicting pancreatic transplant function prior graft implantation.

Acridine Orange↗
PubMed1996

Immunohistochemical study of leucine-enkephalin and its secretory effects in the isolated pig lacrimal gland.

BACKGROUND: In our previous studies immunohistochemical studies have demonstrated the presence of leucine-enkephalin (Leu-Enk) in the intrinsic nerves of the pig lacrimal gland, which are discernible in the interlobular and interacinar areas from where branches that innervate the acinar tissues are sent. Since the intrinsic nerves have been shown to contain Leu-Enk, this study aimed to investigate the secretory effects of this neuropeptide in isolated segments of the pig lacrimal gland and to reconfirm its presence in the neuronal tissue of the lacrimal gland. METHODS: Leu-Enk was identified using immunohistochemical techniques, while total protein output was measured in the effluent samples by an automated on-line colorimetric method. The Ca2+ and Mg2+ concentrations in the effluent samples were determined using an atomic absorbance spectrophotometer. RESULTS: Leu-Enk (10(-12)-10(-7) M) evoked marked increases in total protein output from superfused lacrimal gland segments. The secretory effect of Leu-Enk was not blocked by pretreatment of the tissue with atropine but was substantially reduced by a combination of phentolamine and propranolol. The competitive antagonist, naloxone, has no effect on basal protein output, but when combined with Leu-Enk it caused a significant reduction in total protein output. Combining theophylline (10(-3) M) with Leu-Enk resulted in a marked potentiation of total protein output. In superfused lacrimal gland segments Leu-Enk (10(-8) M) evoked a net efflux of magnesium (Mg2+ release) and a net influx of calcium (Ca2+ intake). CONCLUSION: The results indicated a physiological role for Leu-Enk in the regulation of protein secretion in the pig lacrimal gland.

Animals↗
PubMed1996

Immunohistochemical identification and effects of atrial natriuretic peptide, pancreastatin, leucine-enkephalin, and galanin in the porcine pancreas.

This study demonstrates the presence and distribution of atrial natriuretic peptide (ANP) pancreastatin (PST), leucineenkephalin (Leu-ENK), galanin (GAL), and insulin in the pig pancreas. The effects of PST, ANP, Leu-ENK, and GAL on protein and amylase secretion were also investigated to determine their functional role in the control of pancreatic secretion. PST-immunoreactive cells were observed in the islet of Langerhans and in the wall of the ducts. Leu-ENK-immunopositive cells were observed in both the endo-and exocrine pancreas. It is colocalized with insulin in the islet of Langerhans. ANP immunoreactivity was discernible in nerve fibers and cells of the exocrine pancreas. GAL-immunopositive cells were observed in close association with insulin-positive cells in the islets of Langerhans and in the exocrine pancreas. Stimulation of isolated pancreatic segments with either ANP or Leu-ENK resulted in increased protein secretion and amylase output. The Leu-ENK-evoked amylase secretion was antagonized by naloxone. Pancreastatin was effective at all concentrations, but low concentration had more marked secretory effects whereas GAL failed to evoke any significant increases in either protein or amylase secretion. The results of the study have demonstrated a close association of peptidergic fibers with the secretory cells of the pancreas. The nerve fibers can release peptides that in turn can stimulate protein and amylase secretion.

Amylases↗
PubMed1996

Innervation of the pancreas of the one-humped camel (Camelus dromedarius) by neuropeptide-Y, galanin, calcitonin-gene-related-peptide, atrial natriuretic peptide and cholecystokinin.

The distribution of neuropeptide-Y (NPY), galanin (GAL), cholecystokinin-8 (CCK-8), atrial natriuretic peptide (ANP) and calcitonin gene-related peptide (CGRP) in the pancreas of the camel was investigated using immunohistochemical techniques. NPY-immunoreactive neurons were observed in the pancreatic ganglia and also in the interacinar regions of the exocrine pancreas. NPY was discernible in fine varicose nerve fibres ending on NPY-negative cells and in the walls of blood vessels. ANP immunoreactivity was observed in nerve fibres situated on the basolateral surfaces of the acinar cells. CCK-8, GAL and CGRP immunoreactivity were observed in neurons and varicose nerve fibres in the walls of blood vessels. Of all the neuropeptides investigated, only NPY appeared to be densely distributed in the pancreas of the camel. It is concluded that the pattern of distribution of these neuropeptides in the camel pancreas is similar to those observed in the pancreata of other mammals.

Animals↗
PubMed1996

Pattern of distribution of neuropeptides in the camel lacrimal gland.

The pattern of distribution of neuropeptides, including neuropeptide-Y (NPY), vasoactive intestinal polypeptide (VIP), neurotensin (NT), serotonin (5-HT), galanin (GAL), leucine-enkephalin (LEU-ENK) and calcitoningene-related-peptide (CGRP), in the nerves of the camel lacrimal gland was investigated using immunohistochemical techniques. Fresh lacrimal gland segments, obtained from adult camels slaughtered in the local abattoir, were used for the immunohistochemical techniques. NPY and LEU-ENK immunoreactivity was observed in the nerve cell bodies and nerve fibers of the camel lacrimal gland. VIP, GAL and CGRP were demonstrated predominantly in fine varicose nerve fibers lying on the basolateral surfaces of the lacrimal acinar cells. NT and 5-HT were identified mainly in neurons situated in the periacinar regions, close to the basal surfaces of the acinar cells. It is concluded that the camel lacrimal nerves contain several neuropeptides including NPY, VIP, NT, 5-HT, GAL, LEU-ENK and CGRP which may modulate lacrimal fluid and protein secretion.

Animals↗
PubMed1994

Immunohistochemical identification of galanin and leucin-enkephalin in the porcine lacrimal gland.

The presence and distribution of galanin (GAL) and leucine-enkephalin (LEU-ENK) in the pig lacrimal gland was investigated using immunohistochemical techniques. Lacrimal gland segments obtained from the abattoir were fixed in paraformaldehyde-picric acid solution, cut into 40-50 microns thick sections and processed for immunohistochemistry using polyclonal antisera against GAL and LEU-ENK. GAL- and LEU-ENK-immunoreactive intrinsic multipolar neurons were observed in the interacinar and interlobular areas of the pig lacrimal gland. From these regions these intrinsic neurons send branches to the acinar and other tissues of the gland. Immunoreactivity was confined solely to the neural elements. These two potent biologically active neuropeptides may play important roles in the regulation of lacrimal fluid secretion.

Amino Acid Sequence↗
PubMed1991

Morphometric and immunohistochemical study on the endocrine cells of pancreatic transplants.

The endocrine cells of embryonic pancreatic tissue fragments transplanted into the anterior eye-chamber of rats for 74 days were investigated immunohistochemically and morphometrically and the results obtained were compared with that of normal tissue. Four types of endocrine cells were identified and their distribution was as follows: insulin: 42-52%, glucagon: 11-28%, somatostatin: 4%, and pancreatic polypeptide-positive cells: 3-6%. Their size in square micrometer were as follows: 153, 110, 38 and 51. The area, number, distribution and topography of these endocrine cells with regard to each other did not differ significantly from that of normal tissue. The area of each islet and their cell population vary considerably both in normal and transplanted pancreas.

Animals↗
PubMed1990

Distribution of acetylcholinesterase--and monoamine oxidase--positive neurons in pancreatic tissue transplant.

Acetylcholinesterase-and monoamine oxidase-positive neuronal elements were investigated in embryonic pancreatic tissue fragments transplanted into the anterior eye-chamber of rats for 28, 77, and 135 d, using enzyme histochemical method. Amongst the components of the parenchymal tissue, only the ductal and islets cells survived. Monoamine oxidase (MAO)- and acetylcholinesterase (AChE)-positive neuronal cell bodies and fibres were found to be considerably many in the surviving and newly formed islets of Langerhans, in the wall and periphery of the tubules. Their topography with regards to these components is similar to that in normal tissue. In normal tissue, MAO-positive fibers abut the basal and lateral parts of acinar cells. AChE-positive neurons are most conspicuous in the islets and in the wall of pancreatic ducts.

Acetylcholinesterase↗
PubMed1990

Morphological findings in long-term pancreatic tissue transplants in the anterior eye chamber of rats.

Morphological changes in 21-day-old embryonic and 2-day-old postnatal rat pancreatic tissue fragments transplanted into the anterior eye chamber of homologous animals for 74, 77, 180, and 534 days were investigated using light and electron microscopic, acetylcholinesterase enzyme, and immunohistochemical methods. The pancreatic acinar cells degenerated and were not observed at this stage of transplantation. The ductal system proliferated and partly differentiated into endocrine cells that subsequently formed many new islets of Langerhans as well. The structures of beta-, alpha-, delta-, and pancreatic polypeptide cells were found to be intact even 1.5 years after transplantation. In addition to this, the organization of these cells inside the islets is similar to that of normal pancreatic tissue. The transplanted tissue fragments were well vascularized with blood vessels and innervated also by serotonergic cells and acetylcholinesterase-positive neurons. It is concluded that pancreatic tissue fragments, with the exception of the acinar component, can grow and survive with intact structure in the anterior eye chamber of homologous rats for up to 1.5 years.

Animals↗
PubMed1990

Ultrastructure of pancreatic light and clear cells in normal and transplanted tissue fragments in the anterior eye-chamber of rats.

The ultrastructure of pancreatic light and clear endocrine cells in normal and transplanted tissue fragments in the anterior eye-chamber of rats was described by electron microscopy. Compared to the dark cells, the light cells contain a conspicuously poorly stained cytoplasmic ground substance with varying number of rough endoplasmic reticulum cisterns and secretory granules. The quantities of these two organelles are inversely proportional to each other. "Light" alpha, beta, delta and pancreatic polypeptide cell-types were identified in normal and transplanted tissue. Out of these, the light alpha cell is the most commonly occurring. The "clear" endocrine cells are much fewer in number than the light cells. They contain well stained cytoplasm with numerous low electron density vesicles and few secretory granules. There is no ultrastructural difference between the light and clear cells in normal and in transplanted tissue for 77 and 534 days. The occurrence of light and clear cells in the transplanted tissue shows that these transplants behave morphologically like normal tissue. These cell types might be related to the different stages of secretory granule synthesis and maturation.

Animals↗
PubMed1989

Formation and exocytosis of secretory granules in the endocrine cells of normal and transplanted pancreas: an electromicroscopic study.

The mechanism of secretory granule formation and exocytosis in the endocrine cells of normal and transplanted rat pancreas was studied using electron microscopy. On the one hand, formation of secretory granules starts with the dilatation of the 2 ends or the vesicularization of the middle parts of rough endoplasmatic reticulum (RER). On the other hand, prohormone ribosomes condense into the vesicles of the GOLGI apparatus. This probably indicates that the GOLGI complex is not the only source of formation of secretory granules. Exocytosis occurs with the formation of an electron dense streak between the perigranular membrane and the apical cell membrane. This is followed by the rupture of the streak at this midpoint allowing the granule to extrude into the space between the cell membrane and the parenchymal basal membrane. This fusion-rupture-extrusion mechanism repeats itself at the parenchymal and capillary basal membranes and also at the endothelium until it gets into the capillary lumen, showing that hormones of pancreatic endocrine cells may be actively transported into circulation as intact secretory granules. There is no significant morphological difference between the mechanism of secretory granule formation in normal and transplanted pancreatic tissue.

Animals↗
PubMed1988

Ultrastructural morphology of light beta cells in pancreatic tissue implanted into the anterior eye-chamber of rats.

The ultrastructure of light beta cells in pancreatic tissue implanted into the anterior eye-chamber of homologous rats was described using electron microscopical method. The light beta cells contain more mitochondria and rough-surfaced endoplasmic reticulum cisternae and dilatated smooth endoplasmic reticuli than the dark beta cells. Their cytoplasm are poorly stained and contain secretory beta granules of similar morphological form to those in the dark cells. The secretory granules are also more heterogenous. The light cells seem to represent the early secretory stages of the beta cells.

Animals↗