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Biomedical subjects

O Eränkö

Publications and source records attributed to O Eränkö.

At least 19 recordsLinked to original sources
PubMed1986

Age-dependent stimulation by atrium explants or nerve growth factor of nerve fibre outgrowth from cocultured embryonic rat sympathetic ganglia.

Whole sympathetic superior cervical ganglia of 14- and 15-day-old rat embryos were cultured in a collagen gel medium for 24 h with or without explants of heart atrium from the same animals or from newborn rats. The extent of nerve fibre outgrowth was estimated by counting the number of nerve fibres crossing each arc of a sector drawn in the microscope ocular. Only few nerve fibres extended from the ganglia of the 14-day-old embryos cultured in the pure control medium. Addition of exogenous nerve growth factor did not stimulate the poor growth. While the growth of nerve fibres in the presence of atrium explants of newborn rats did not significantly differ from that in cultures without any target tissue, the presence of atrium explants of the same, 14-day-old, embryo resulted in clearly enhanced fibre outgrowth from the ganglia, which was inhibited by antiserum to the nerve growth factor. The ganglia of 15-day-old embryos cultured without target tissue in the control medium produced only sparse fibre outgrowth which was excessively increased by exogenous nerve growth factor. Coculture with atrium explants of 15-day-old embryos or newborn rats produced an increased overall nerve fibre growth, as well as predominance of those fibres growing toward the target tissue. The growth-promoting effect of the atrium of 15-day-old embryos was only partially prevented by antiserum to the nerve growth factor, while that elicited by newborn rat atrium was totally inhibited.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1985

Histamine-immunoreactive cells in the superior cervical ganglion and in the coeliac-superior mesenteric ganglion complex of the rat.

Histamine-immunoreactive small cells were detected in the superior cervical ganglion and in the coeliac-superior mesenteric ganglion complex of the rat with a specific antiserum produced in rabbits. Most histamine-immunoreactive cells were arranged in clusters, often around small blood vessels. Solitary immunoreactive small cells were also observed and they were easily distinguished from mast cells. The principal nerve cells showed no immunoreactivity to histamine and no histamine-containing nerve fibers were detected in the ganglia by the present method. Due to close morphological similarities, it is concluded that the small immunoreactive cells observed in the present study represent small intensely fluorescent (SIF) cells first detected by formaldehyde-induced catecholamine fluorescence.

Animals↗
PubMed1984

Effect of hydrocortisone on immunohistochemically demonstrable phenylethanolamine-N-methyltransferase in cultures of embryonic and postnatal superior cervical ganglia.

Pre- and postnatal superior cervical ganglia of the rat were cultured in Rose chambers for 1-7 days with or without hydrocortisone. Phenylethanolamine-N-methyltransferase (PNMT) was demonstrated by indirect immunofluorescence technique. In cultures without added hydrocortisone, no cells or fibres showed PNMT-immunoreactivity, without regard to the time in culture or the developmental stage at the time of explantation. The first PNMT-immunoreactive cells in hydrocortisone-containing cultures appeared 3 days after the explantation of E14 ganglia, or 1 day after the explantation of E15 ganglia, i.e. at the developmental stage E16-E17. The cultures of neither E14 nor E15 ganglia showed marked fibre growth from the PNMT-immunoreactive cell bodies. On the other hand, in the hydrocortisone-containing cultures of newborn or postnatal rats, there was extensive nerve fibre formation from the PNMT-immunoreactive cells in the course of the culture. PNMT-immunoreactive cells did not appear in hydrocortisone-containing cultures of ganglia taken from rats older than 17 postnatal days.

Animals↗
PubMed1984

Intensely fluorescent cells in embryonic and postnatal superior cervical ganglia of the rat cultured with or without hydrocortisone.

Pre- and postnatal superior cervical ganglia of the rat were cultured in Rose chambers for 1-7 days with or without hydrocortisone. Fibre growth of the principal nerve cells was observed by phase contrast microscopy, and the explants were then processed for formaldehyde-induced catecholamine fluorescence. The ganglia of 13-day-old embryos cultured for 7 days in the control medium did not show fibre growth and contained only one type of fluorescent cells, the weakly fluorescent, presumably principal nerve cell, while in the older ganglia the principal nerve cells formed a fibre network, and the ganglia also contained a few small intensely fluorescent cells some of which had short processes. The ganglia of 15-day-old embryos and newborn rats cultured for 1 day in a control medium contained cells that showed a continuous range of weak through bright fluorescence. In the course of the culture, the cells of intermediate fluorescence intensity disappeared, and the number of the intensely fluorescent cells greatly decreased, more slowly in the newborn than in the embryonic ganglia. The intensely fluorescent cells in the newborn, but not those in the embryonic ganglia transiently produced marked fibre growth within the explants. All embryonic ganglia and 6-day-old or younger postnatal ganglia cultured in hydrocortisone-containing medium for 7 days showed a much greater number of intensely fluorescent cells than the corresponding control ganglia. Examination of the cultures 1, 2, 4, or 7 days after the explantation showed that in both pre- and postnatal ganglia hydrocortisone resulted in the appearance of both neuroendocrine and fibre-growing types of intensely fluorescent cells. These observations support the idea that during a limited period of pre- and postnatal development, the sympathetic ganglia contain a population of cells which are able to change their phenotype in the presence of glucocorticoids.

Aging↗
PubMed1984

Effect of pre- and/or postganglionic nerve division on hydrocortisone-induced small intensely fluorescent cells in the rat superior cervical ganglion.

Daily hydrocortisone injections into newborn rats cause in a week about a 10-fold increase in the number of small intensely fluorescent cells in the superior cervical ganglion of the rat, as compared with untreated rats of the same age. The glucocorticoid-induced increase in the number of small intensely fluorescent cells is reversible. After discontinuation of the glucocorticoid treatment there is a significant decrease in the number of these cells during the 2nd postnatal week. The purpose of the present study was to investigate the significance of the innervation of the superior cervical ganglion on the fate of newly formed, hydrocortisone-induced small intensely fluorescent cells after discontinuation of the hydrocortisone treatment. Three-day-old rats were injected daily with hydrocortisone for 7 days. At the age of 10 days the pre- and/or postganglionic trunk(s) on one side were divided and the contralateral side served as control. Seven or thirty days after discontinuation of the hydrocortisone injections and the operation (i.e. at the age of 17 or 40 days) the rats were killed and the small intensely fluorescent cells were counted. The number of small intensely fluorescent cells, as expected, was greatly increased by the hydrocortisone injections. However, discontinuation of the treatment resulted in a decrease in the number of these cells in unoperated 40-day-old rats to a level, which is significantly less than the mean cell number/ganglion in totally untreated adult rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Immunohistochemical localization of unique enkephalin sequences contained in preproenkephalin A in the guinea pig cochlea.

The guinea pig cochlea was studied for the presence of immunoreactivities to the four unique enkephalin sequences contained in the preproenkephalin A. The antisera to Met-enkephalin-Arg6-Phe7 and Met-enkephalin-Arg6-Gly7-Leu8 were used as highly specific markers for the preproenkephalin A. Contrary to Met-enkephalin and Leu-enkephalin, also included in the present study, these two peptide sequences are not contained in pro-opiomelanocortin or preproenkephalin B (prodynorphin). All the four different antisera showed identical localization for the four peptide sequences, suggesting their coexistence in the same nervous pathway. Specific immunofluorescence was found in intraganglionic spiral bundle, inner spiral bundle, tunnel spiral bundle and in association with inner hair cells. The nerve fibers were thin and varicose, suggesting that most, if not all, of them were unmyelinated. Their localization indicates that the unique enkephalin sequences contained in preproenkephalin A are present in the cochlear efferent pathway to the inner hair cell region.

Animals↗
PubMed1984

Fluorescence microscopical study on fibre formation from carotid bodies from normal or dexamethasone-treated postnatal rats in intraocular transplants to adult rats.

Carotid bodies from untreated newborn and adult rats or dexamethasone-treated 7-day-old and adult rats were homologously transplanted into the anterior eye chamber of adult female rats. The eyes of the host rats were sympathetically denervated one day before the transplantation. The transplants and irides were examined at various times postoperatively by formaldehyde-induced catecholamine fluorescence. Transplants attached to and were vascularized by the iris of the host eye. The carotid body glomus cells in the transplants from untreated newborn and dexamethasone-treated 7-day-old rats regularly migrated on the iris, while migration from the adult carotid body transplants occurred only occasionally. The migrated glomus cells usually grew only short processes, but in one out of 55 transplants from untreated newborn rats and in one out of 48 transplants from untreated adult rats a fibre network was formed around the transplant. Twenty three transplantations from 7-day-old dexamethasone-treated rats were made and in 5 of them a fibre network was formed around the transplant. In some cases the nerve fibres could be seen to extend from individual glomus cells. There was no fibre outgrowth from the 13 carotid bodies transplanted from dexamethasone-treated adult rats. Pieces of adrenal medullary tissue, which previously has been shown to partially reinnervate the sympathetically denervated iris, was transplanted for comparison. They always formed a fibre network around the transplant. It is concluded that carotid body glomus cells do not have the phenotypic plasticity to form nerve fibres in intraocular transplants as do the adrenal medullary cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Medulla↗
PubMed1984

Effect of ten different target tissues on nerve fibre outgrowth from rat sympathetic ganglia in organotypic co-cultures.

Sympathetic thoracic chain ganglia of 3-day-old rats were cultured in collagen gel medium for 24 hours together with explants from heart atrium, liver, kidney, cornea, iris, lung, adrenal cortex, adrenal medulla, skeletal muscle, or vas deferens. The extent of nerve fibre growth was estimated by counting the number of fibres crossing each arc of a sector drawn in the ocular. The various tissues stimulated nerve fibre growth to distinctly different extents. The increase in the nerve fibre outgrowth induced by atrium and iris was statistically highly significant. Kidney, liver, vas deferens, lung, and adrenal cortex had, in that order, a decreasingly stimulatory influence on sympathetic chain ganglia. Yet they all caused a significant increase in nerve fibre growth. Skeletal muscle, cornea and adrenal medulla had no stimulatory effect. Since the significant effects of the tissue explants were abolished by antiserum to nerve growth factor (NGF), it is concluded that the observed effects were due to NGF produced by the explants. The only exception was vas deferens, the stimulatory action of which proved to be partially NGF-independent.

Adrenal Glands↗
PubMed1983

Endocytosis of cationized ferritin to vesicles in the Golgi region of the glomus cells dissociated from the adult rat carotid body.

Glomus cells were dissociated from the carotid bodies of adult rats by enzymatic digestion with collagenase. The cells were then incubated at 37 degrees C for 30 minutes to 3 hours in the continuous presence of cationized ferritin (CF) as a membrane marker and extracellular tracer to study the intracellular route of endocytosis in this cell type. After 30 minutes of incubation with CF, occasional solitary CF-containing vesicles were observed at the cell periphery and also in the Golgi region. After 2-3 hours of incubation with CF, cell viability was still preserved and CF-labeled vesicles were abundant in the Golgi region. CF particles were also seen in some vesicles having a dense core. The core of these labeled vesicles appeared to be less electron-dense than that of typical secretory granules. It is suggested that the Golgi apparatus is involved in membrane recycling in glomus cells and that the membrane is then possibly further transported to an immature type of storage vesicle for reusage.

Animals↗
PubMed1983

Increase in the number of non-neuronal cells in superior cervical ganglia of developing rats after contralateral ganglionectomy.

The left superior cervical ganglion of 3-day-old rats was subjected to preganglionic nerve division, ganglionectomy, or sham operation, while the right ganglion was left intact. Thirty days later, both the left and the right ganglia were perfusion-fixed and examined for weight and volume, as well as for the number and the density of the principal nerve cells and the non-neuronal cells. The small intensely fluorescent cells were counted from a separate set of freeze-dried ganglia. Unilateral preganglionic nerve division caused in the left operated side a significant loss of ganglion weight and volume due to a decreased number of non-neuronal cells, while no significant changes occurred in the right intact ganglion. Unilateral left ganglionectomy caused a significant increase in the mean ganglion weight and in the number and the density of the non-neuronal cells in the right intact ganglion, while the number and the density of the principal nerve cells and the small intensely fluorescent cells were not affected by this operation. It is suggested that normal development of the ganglionic satellite cells requires the presence of normally innervated principal cells. Furthermore, unilateral ganglionectomy induces a greater than normal proliferation of the satellite cells contralaterally, possibly by causing an increase in the activity of the contralateral ganglion.

Animals↗
PubMed1983

Substance P immunoreaction and acetylcholinesterase activity in the cornea and Gasserian ganglion.

Nerves showing acetylcholinesterase (AChE) activity or immunoreactivity for substance P (SP) were demonstrated in the human cornea. AChE-positive fibres were found in stromal nerve trunks from where they penetrated Bowman's membrane and formed a basal epithelial plexus. Intraepithelial terminals arose from this network. SP immunoreactive nerve fibres showed similar architecture but were fewer. Both SP immunoreaction and histochemical AChE reaction were demonstrated consecutively in the same tissue section cut from both human and rabbit cornea. Stromal nerve trunks were found to contain SP immunoreactive and AChE-positive nerve fibres. However, the AChE-positive fibres were much more frequent than those immunoreactive for SP. In the rabbit Gasserian ganglion all neurons showed AChE activity but only some 20% were SP positive. It is concluded that all the sensory trigeminal nerve fibres of the cornea show AChE activity but only a proportion of them contain SP-like material.

Acetylcholinesterase↗
PubMed1983

Substance P immunoreactivity in normal human retina and in retinoblastoma.

Substance P (SP) immunoreactivity was demonstrated using the indirect immunofluorescence technique in one normal and one retinoblastomatous human retina. In the normal retina SP immunoreaction was located in nerve fibres but not in the neurons in the inner plexiform layer. A similar location was observed in the histologically normal areas of the retinoblastoma sample. SP immunoreactive neurons, probably amacrine cells, were, however, observed in the transitional area between the normal retina and the tumour. The tumour mass, although mainly SP negative, contained clusters of pleomorphic cells with an intense SP immunoreaction. The general distribution of SP immunoreaction in human retina resembles that of other mammals. The positive SP immunoreaction in retinoblastoma cells suggests that the tumour either may have its origin in the amacrine cells or that the retinoblasts are capable of redifferentiating in the direction of the amacrine cell population. The general problems concerning the origin and pathogenesis of retinoblastoma are discussed.

Child, Preschool↗
PubMed1982

Endocytotic uptake of cationized ferritin tracer into glomus cells dissociated from the adult rat carotid body.

Glomus cells from carotid bodies of adult rats dissociated by means of collagenase or collagenase + trypsin were used to study by electron microscopy the endocytotic uptake of cationized ferritin (CF) tracer into subcellular compartments. The glomus cells were incubated with the tracer (1) in a basic salt medium (BM), or (2) in the BM into which calcium ionophore A23187 had been added, or (3) in a potassium-rich medium. Incubation of the cells in BM containing CF for 30 min resulted in attachment of the tracer to the cell membrane and uptake of a few solitary tracer particles into small vesicles and multivesicular bodies. No uptake into the cisternae of the Golgi apparatus was observed. Further incubation in BM containing CF for another 30 min resulted in increased uptake of the tracer into small vesicles and multivesicular bodies. A similar pattern of uptake was observed when the dissociated glomus cells were first preincubated in BM with CF for 30 min and then incubated for 1 min or 30 min in the BM solution containing both the ionophore and CF. Upon such incubation, CF particles were seen to penetrate into coated pits and sites of exocytosis at the cell surface. When the 30-min preincubation in BM was followed by incubation in a CF-containing potassium-rich medium for 15-30 min, uptake into vesicles, small lysosomes and occasionally also into profiles of the smooth endoplasmic reticulum was seen. Endocytotic mechanisms of the glomus cells are outlined.

Animals↗
PubMed1982

Effect of hydrocortisone on catecholamines and the enzymes synthesizing them in the developing sympathetic ganglion.

Newborn rats were daily injected with 0.2 mg hydrocortisone acetate for seven days. They were killed 1, 7 or 21 days after the last injection, together with untreated controls. Hydrocortisone caused a great increase in the number of the small, intensely fluorescent (SIF) cells and the appearance of similar small cells with intense immunohistochemical reactions for tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine (noradrenaline) N-methyltransferase (PNMT) in the superior cervical ganglion. At the same time, the adrenaline content and the PNMT activity of the ganglion greatly increased, while no significant changes were observed in the dopamine or noradrenaline content or TH or DBH activity. All these changes essentially disappeared after a recovery period of seven or 21 days. It is concluded that hydrocortisone caused a temporary increase in the number of SIF cells by causing a synthesis of TH, DBH and PNMT in previously existing small, non-fluorescent cells, which start to synthesize and store adrenaline, thus becoming intensely fluorescent SIF cells. These SIF cells are different from the normal SIF cells of the same ganglion, most of which appear at a later stage of postnatal development when response to hydrocortisone is lost, which contain TH but neither DBH nor PNMT, and which permanently remain in the ganglion.

Animals↗
PubMed1982

Number of neurons and dexamethasone-induced SIF cells in developing sympathetic ganglia and in intraocular ganglion transplants.

Daily dexamethasone (DM) injections to newborn rats caused in a week an increase in the number of small intensely fluorescent (SIF) cells in the superior cervical ganglion to a value 9 times that in the ganglia of saline-treated controls. The number of SIF cells (per ganglion) decreased in another week both in ganglia transplanted into the anterior chamber of the eye of an adult rat and in intact ganglia of rats allowed to live for another week after discontinuation of the DM treatment. However, in both cases the number of SIF cells was significantly higher than that in the newborn rat ganglia. The number of SIF cells also decreased in transplanted ganglia from saline-treated controls, the number of SIF cells in transplants from DM-treated rats being 10 times as high as that in the transplants from saline-treated rats. The SIF cells formed large clusters in transplants from DM-treated rats and their density (cells/mm3) was significantly higher than that in the ganglia left in situ for one week after discontinuation of the DM treatment. Therefore, visual examination suggested that there is little or no loss of SIF cells due to transplantation. The transplantation caused an over 90% loss of neurons and a marked decrease in ganglion volume.

Aging↗
PubMed1982

Effect of pre- and postganglionic nerve divisions on normal postnatal and hydrocortisone-induced development of small intensely fluorescent cells in rat superior cervical ganglion.

The left superior cervical ganglion of 3- or 23-day-old rats was subjected to pre- and/or postganglionic nerve division or sham operation, while the right ganglion was left intact. The animals were killed 20 or 60 days after the operation. Some animals were injected with 20 mg/kg hydrocortisone daily for 7 days and killed on the 8th day. Fluorescence microscopical examination revealed a normal postnatal increase in the number of small intensely fluorescent cells/ganglion after pre- or postganglionic nerve division, in spite of marked decreases in the volume of the operated ganglia. Combined pre- and postganglionic nerve division, which caused a dramatic loss of ganglion volume, entirely prevented the postnatal increase in the number of small intensely fluorescent cells. Hydrocortisone caused a large increase in the number of small intensely fluorescent cells both in intact and operated ganglia, including those in whom both pre- and postganglionic nerves had been divided. It is concluded that combined pre- and postganglionic denervation, in contrast to either operation alone, prevents the normal proliferation of the small intensely fluorescent cells possibly by causing an extensive loss of principal nerve cells which deprives the small intensely fluorescent cells of their normal contacts with the principal cells. Since the increase in the number of small intensely fluorescent cells due to hydrocortisone injections was not prevented by pre- and postganglionic denervation it must be due to a mechanism different from that responsible for the formation of small intensely fluorescent cells during normal postnatal development.

Animals↗
PubMed1982

Substance P-immunoreactive nerves in the human cornea and iris.

Human corneas and irides obtained from corneal surgery or sector iridectomies were processed according to the indirect immunofluorescence technique for the demonstration of substance P (SP) immunofluorescence by means of a monoclonal SP antibody. SP immunofluorescence was observed in varicose fibers of the corneal epithelium and nerve trunks in the corneal stroma. SP-immunoreactive nerve fibers in the iris were detected mainly in the pupillary margin in both dilator and sphincter areas.

Cornea↗