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L Rechardt

Publications and source records attributed to L Rechardt.

At least 37 records · Page 2Linked to original sources
PubMed1990

Immunocytochemical study of the relations of acetylcholinesterase, enkephalin-, substance P-, choline acetyltransferase- and calcitonin gene-related peptide-immunoreactive structures in the ventral horn of rat spinal cord.

Calcitonin gene-related peptide (CGRP)-like immunoreactivity was localized immunocytochemically in the large motoneurons in the ventral horn of rat spinal cord. Using fluorescence double-labelling substance P (SP)-immunoreactive nerve fibres were found to surround both the CGRP-positive and negative motoneurons, whereas enkephalin (ENK)-immunoreactive fibres surrounded mainly CGRP-negative cells. All CGRP-like immunoreactive motoneurons were also choline acetyltransferase (ChAT)- and acetylcholinesterase (AChE)-positive. On the other hand a large population of ChAT- and AChE-positive motoneurons were devoid of CGRP-immunoreactivity. It is probable that CGRP/ChAT/AChE-positive cells surrounded by SP-positive fibres have different functions in motoric nervous system than the CGRP-negative ChAT/AChE-positive cells, which are surrounded by ENK-immunoreactive fibres.

Acetylcholinesterase↗
PubMed1990

Neuropeptides in cutaneous neurofibromas of von Recklinghausen's disease.

The occurrence of neuropeptides was studied in neurofibromas of von Recklinghausen's disease by indirect immunofluorescence. All non-plexiform cutaneous neurofibromas contained abundant vasoactive intestinal polypeptide, peptide histidine-isoleucine and calcitonin gene-related peptide immunoreactive nerves. The nerves were small and unmyelinated. Neuropeptides might be responsible for itch that occurs especially in small cutaneous neurofibromas. Neuropeptides are also suggested to act as modulators and/or trophic factors for neurofibroma growth.

Calcitonin Gene-Related Peptide↗
PubMed1989

Calcitonin gene-related peptide immunoreactivity in prurigo nodularis: a comparative study with neurodermatitis circumscripta.

Eight patients with intensely pruritic lesions of chronic idiopathic prurigo nodularis and three patients with neurodermatitis circumscripta were investigated using the indirect immunofluorescence method. Results showed similarities in epidermal hyperplasia but not in nerve proliferation and neuropeptide immunoreactivity. Increased numbers of calcitonin gene-related peptide (CGRP) and substance P immunoreactive nerve fibre bundles were detected in specimens taken from prurigo nodularis lesions, but no increased immunoreactivity could be seen in specimens taken from patients having neurodermatitis circumscripta compared to normal skin. The neuropeptides, CGRP and substance P, may be responsible for the intense itching of prurigo nodularis lesions.

Calcitonin↗
PubMed1988

Light and electron microscopic immunocytochemical demonstration of intraepidermal CGRP-containing nerves in human skin.

The distribution of nerves immunoreactive to calcitonin gene-related peptide (CGRP) was studied in human skin with special reference to the intraepidermal nerve fibres. It was shown by light and electron microscopy that a small proportion of the CGRP immunoreactive nerves entered the epidermis. The majority of the nerves ended as free nerve terminals subepidermally. Intraepidermal nerve endings were mainly seen in skin areas, which have a dense sensory innervation, such as fingertips and foreskin. The role of the peptidergic nerves in human skin is discussed.

Calcitonin Gene-Related Peptide↗
PubMed1987

Catecholamine-synthesizing enzymes in the rat pituitary. An immunohistochemical study.

The catecholamine-containing nerve fibers of the rat pituitary were studied by immunohistochemical demonstration of the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine N-methyltransferase (PNMT). Immunohistochemical demonstration of TH confirms earlier catecholamine fluorescence histochemical studies showing a fine network of varicose fibers in both the intermediate and the neural lobe, with the most dense aggregation of fibers at the border between the lobes. DBH-immunoreactive fibers were much less in number, and confined to the neural lobe, where both vascular and parenchymal fibers were seen. With the antibody to PNMT bright staining was seen in all the glandular cells of the intermediate lobe, while the neural lobe was negative. No immunoreactive structures were observed in the anterior lobe. Functionally the study confirms the presence of an extensive dopaminergic innervation of the neurointermediate lobe, giving an anatomical basis for the tonic inhibitory action of dopamine on the intermediate lobe cells and for recent observations attributing dopamine a local regulatory function also in the neural lobe. In addition to vascular noradrenaline-containing fibers as described earlier the study shows parenchymal DBH-immunoreactive fibers in the neural lobe, suggesting a local role for noradrenaline in this lobe. The nature of the cellular PNMT-immunoreactivity in the intermediate lobe remains to be established. The cellular localization of the PNMT-immunoreactivity was distinctly different than that of the alpha-MSH-immunoreactivity within the intermediate lobe cells and reserpine treatment did not affect the PNMT-immunoreactivity although it induced a heterogeneous depletion of alpha-MSH and related peptides.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

The distribution of sympathetic adrenergic, tyrosine hydroxylase- and neuropeptide Y-immunoreactive nerves in human axillary sweat glands.

The innervation of human axillary sweat glands was studied by using the specific SPG (sucrose-potassium phosphate-glyoxylic acid) catecholamine histofluorescence method and the peroxidase-antiperoxidase (PAP) immunocytochemical method. The present results demonstrated that human sweat glands are surrounded by nerves containing a weak tyrosine hydroxylase activity. Nerves showing catecholamine histofluorescence could be visualized around the sweat glands only in the presence of exogenous catecholamine (adrenaline in the local anestheticum). In all tissue specimens studied fluorescent adrenergic nerves could be seen around arteries and arterioles corresponding to the distribution of neuropeptide Y-like immunoreactive nerves.

Adrenergic Fibers↗
PubMed1986

Light and electron microscopic demonstration of neuropeptide Y-like immunoreactive nerves in human cardiac muscle.

Neuropeptide Y (NPY)-like immunoreactive nerves were demonstrated in human cardiac muscle. The atrial specimens were obtained from open-heart surgery. The PAP method was applied for immunocytochemistry for light and electron microscopy. A dense, extensive network of NPY-like immunoreactive nerve fibres was seen between cardiac muscle cells and around blood vessels. In electron microscope PAP precipitates were localized in large dense-cored vesicles of 80-120 nm in size in separate nerve terminals or in the terminals situated in the nerve bundles. Close contacts were observed between NPY nerves and muscle cells and blood vessels. The possible functional role of NPY innervation in the human heart is discussed.

Heart↗
PubMed1986

Peptidergic innervation of human atrial myocardium: an electron microscopical and immunocytochemical study.

Nerve terminals of human cardiac muscle were studied using an electron microscope. Substance P-, Leu-enkephalin- and vasoactive intestinal polypeptide-like (VIP) immunoreactive nerves were demonstrated by use of the light microscope. In addition, VIP- and substance P-like immunoreactive nerves were localized ultrastructurally by the peroxidase-antiperoxidase-method. Muscle specimens were obtained from right auricula of patients undergoing open-heart surgery. In the nerve fibres and terminals, which were situated close to the blood vessels and cardiac muscle cells several vesicle populations were identified. On the morphological basis the terminals could be tentatively categorized as cholinergic, mixed cholinergic-peptidergic, adrenergic, sensory or baroreceptor type, peptidergic and degenerating nerve endings. Substance P-, Leu-enkephalin- and VIP-like immunoreactive nerves were localized between cardiac muscle cells. Nerve terminals, which showed substance P-immunoreaction were observed also close to blood vessels. In substance P- and VIP-immunoreactive nerve terminals the immunoprecipitation was localized in large dense-cored vesicles of about 120 nm in diameter. It is concluded that the intrinsic control of the human heart is most probably regulated by several transmitter candidates. The peptidergic nerves may exert their modulatory interactions in the nerve bundles where they are situated close to each other but a direct effect on the blood vessels and muscle cells cannot be excluded.

Enkephalin, Leucine↗
PubMed1986

Specific detection of neuronal cell bodies: in situ hybridization with a biotin-labeled neurofilament cDNA probe.

We have used a biotinylated, 300-nucleotide cDNA probe which encodes the 68,000 MW neurofilament protein to detect neurofilament-specific mRNA in situ. The neurofilament message specifically demonstrates the neuronal cell bodies, in contrast to the usual antibody staining which detects their neurites. The hybridization is detected only in neuronal structures. Consequently, detection of the biotinylated neurofilament DNA probe by silver-intensified streptavidin-gold can be specifically used to identify neuronal cell bodies.

Animals↗
PubMed1986

Substance P- and leu-enkephalin-immunoreactive nerves before and after myocardial ischaemia, hypothermic chemical cardioplegia and reperfusion injury during open-heart surgery.

During open-heart surgery, myocardial biopsies were obtained before the start of extracorporeal circulation (from the right auricular appendage) and after weaning from the pump (from the right atrium), and processed for immunocytochemical demonstration of substance P- and leu-enkephalin-immunoreactive nerve fibres and for electron microscopy. Substance P-immunoreactive nerves were seen around blood vessels, between myocardial cells and forming large glomerulus-like loops, but were not numerous. Leu-enkephalin-immunoreactive nerves were very sparse. We therefore believe that both nerve types primarily are modulatory axons. In the post-weaning specimens, nerves of both types were more numerous (attributable to the different site of biopsy), and no change was seen in the immunofluorescence reaction. The ultrastructure (all types) of nerve terminals was well preserved, although myocardial damage was obvious in many specimens. Cardiac nerves, including peptidergic nerves, thus seem to be relatively resistant to ischaemia, hypothermic chemical cardioplegia and reperfusion injury.

Biopsy↗
PubMed1986

Rod-like intramitochondrial inclusions after hypothermic chemical cardioplegia during cardiac operations.

Rod-like intramitochondrial inclusions in the myocardial cells were observed after hypothermic chemical cardioplegia in three out of 20 patients who underwent coronary bypass operations. They were not seen in another group of 20 patients who underwent an aortic valve replacement operation in whom only topical cooling was used for myocardial protection. The occurrence of rod-like intramitochondrial inclusions could not be correlated with other signs of ischemic myocardial injury. X-ray microanalysis did not reveal any inorganic substance in the intramitochondrial inclusions. Therefore, we believe that their occurrence was not related to the calcium paradox phenomenon, a feared complication of cardiac operations.

Adult↗
PubMed1985

The effect of reserpine on the pars intermedia of the rat pituitary. An electron-microscopic, fluorescence-histochemical and immunohistochemical study.

Reserpine has a stimulatory effect on the pars intermedia of the rat pituitary, probably mediated by its action on regulatory catecholaminergic nerves. The effect of single intraperitoneal injections of 0.1-20 mg/kg b.w. of reserpine was studied in adult male rats. Reserpine at a dose of 2 mg/kg b.w. induced degranulation, orientation of the secretory granules along the cell membrane and loss of formaldehyde-chloral-induced fluorescence, accompanied by an activation of the granular endoplasmic reticulum and the Golgi apparatus. With higher doses progressive degranulation and loss of fluorescence were observed. The effect was, however, heterogeneous, and with all doses cells displaying normal ultrastructure and normal fluorescence were regularly present. To study the release of granular products (containing a different components of the pro-opiomelanocortin chain) from individual cells, formaldehyde-chloral induced fluorescence and alpha-MSH- and beta-endorphin immunoreactivies were demonstrated in consecutive sections from pituitaries of rats given 8 mg/kg body weight of reserpine 24 h before sacrifice. The results indicate coordinated release of these granular products at the cellular level after reserpine treatment.

Animals↗
PubMed1985

Cytochemical demonstration of adenylate cyclase activity with cerium.

Cerium was applied for the ultrastructural, cytochemical localization of adenylate cyclase (EC 4.6.1.1.). The enzyme activity was stimulated with norepinephrine, prenalterol and cholera toxin in the brown fat cells of newborn rats. The final reaction product was observed in the plasmalemmas of the stimulated adipocytes. The precipitate was finely crystalline, easily visible in the electron microscope and in the X-ray microprobe analysis it yielded cerium and phosphate peaks, respectively. The use of cerium offers a new tool valid for the cytochemical localization of adenylate cyclase enzyme related to the membrane receptors.

Adenylyl Cyclases↗
PubMed1985

Vasoactive intestinal polypeptide (VIP)-like immunoreactivity in the nerves of human axillary sweat glands.

The cholinergic innervation of the human axillary sweat glands of hyperhidrotic patients was demonstrated by using the specific Karnovsky-Roots thiocholine method. The cholinergic innervation pattern was compared with the immunohistochemically demonstrated vasoactive intestinal polypeptide (VIP)-like activity at light and electron microscopic levels. The innervation patterns were identical in the light microscopic serial sections. In the electron microscope sections, VIP-like immunoreactivity was localized to the nerve terminals containing large, dense-cored vesicles 100-140 nm in size. No synapses were found, however positively stained nerve terminals were located immediately outside the basement membrane but close to the glandular secretory and myoepithelial cells, blood vessels, and occasionally the mast cells. Our results suggest the coexistence of the two neurotransmitters, acetylcholine and VIP, in the same nerves innervating both eccrine and apocrine sweat glands in human axillae.

Acetylcholinesterase↗
PubMed1984

Neuronal differentiation in F9 embryonal carcinoma cells.

F9 line embryonal carcinoma cells were induced to differentiate into neural direction by long-term treatment of monolayer cultures with retinoic acid and dibutyryl cyclic AMP. Bi- and multi-polar cells appeared, expressing acetylcholinesterase and neurofilament proteins but not markers of glial differentiation including GFA-protein. Nerve growth factor combined with both retinoic acid and dibutyryl cyclic AMP greatly enhanced the development of neuron-like morphology and induced expression of immunoreactivity to tyrosine hydroxylase as well as to Leu-encephalin-like peptides. Similarly, serotonin-like immunofluorescence but not substance P-like immunoreactivity was demonstrable in such cultures. In addition, synaptic-like vesicles were often found in the processes. Analysis of matrix expression in neuronally differentiated F9 cells revealed marked increase in laminin production, as judged by immunofluorescence and immuno-electron microscopy, but no demonstrable intracellular staining for fibronectin or type IV collagen. The results with neuronal cells contrast with the expression of all the three matrix components in endodermally differentiating F9 cells in the same cultures.

Animals↗
PubMed1984

Scanning electron microscopy and X-ray microprobe analysis in detection of acetylcholinesterase in cultured embryonal carcinoma cells.

Mouse F9 cells, induced by retinoic acid and dibutyryl cyclic adenosine monophosphate (cAMP) to differentiate into neural-type cells, were incubated for localization of specific acetylcholinesterase (AChE) activity according to the Karnovsky-Roots method where the final enzymatic reaction product is crystalline cupric ferrocyanide and cuprous thiocholine iodide. By scanning electron microscopy (SEM) neural-type cells with long processes were seen. Most of these cells exhibited crystalline precipitates on their surface that in microprobe analysis contained copper, iron, and sulfur. These elements were also detected in some of the neural-type cells that had no visible surface precipitates. Thus, the X-ray analysis also revealed intracellular enzymatic activity. Undifferentiated rounded cells, devoid of AChE activity at the light microscope level, did not show any surface precipitates by SEM and lacked copper, iron, and sulfur emission peaks in the elementary analysis. These results demonstrate that elementary analysis of cytochemical enzymatic reaction products by SEM can be used in identifying cells.

Acetylcholinesterase↗