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Biomedical subjects

M R Celio

Publications and source records attributed to M R Celio.

At least 109 records · Page 6Linked to original sources
PubMed1985

Parvalbumin in human brain.

Parvalbumin was isolated from human cerebral cortex and biceps and triceps muscles by HPLC. The immunological properties of the human protein and the mobility in two-dimensional polyacrylamide gels were similar to that of parvalbumin isolated from the muscles of rat, mouse, rabbit, and chicken. The tryptic peptide maps of the human parvalbumin, however, differed considerably from all other parvalbumins, indicating a distinct primary structure. The immunolabeled cells in the hippocampus of the human brain were of different sizes and forms; they occurred in all subfields and probably represent interneurons.

Adult↗
PubMed1985

Ectopic parvalbumin-positive cells in the cerebellum of the adult mutant mouse 'nervous'.

The basket and stellate cells of the 'nervous' mouse cerebellum lose 50% of their presynaptic parallel fibres and more than 90% of Purkinje cells, their major postsynaptic targets, after postnatal day 23. To study the fate of these molecular layer cells we examined the cerebellum of the mutant mouse 'nervous' with antisera against the 'marker protein' parvalbumin, which exclusively tags Purkinje, basket, and stellate cells. Ten homozygous 'nervous' mice, 12-14 weeks old, and 30 control animals of several inbred strains were examined. The number of basket and stellate cells decreased in affected areas of the molecular layer. In addition, parvalbumin-positive cells were detected in the granular layer, in the white matter of the cerebellum and in the area of the cerebellar peduncles of all 'nervous' mice, but not in those of the control animals. These cells mainly occurred in areas which still displayed degenerating Purkinje cell axons. Ectopic parvalbumin-positive cells could either represent a class of interneurons, which have changed their antigenic properties, and therefore happen to stain with antisera against parvalbumin, or stratum moleculare cells which have failed to recognise their proper position during ontogenesis. Alternatively these cells could represent postdevelopmental basket cells, which have acquired the ability to migrate.

Animals↗
PubMed1984

Parvalbumin in non-muscle tissues of the rat. Quantitation and immunohistochemical localization.

Parvalbumin, a high affinity Ca2+-binding protein, is known to be expressed only in muscles and brain in the rat. We have investigated its distribution and characteristics in other rat tissues by several biochemical and immunohistochemical methods. Evidence for the presence of parvalbumin in teeth, bone, skin, prostate, seminal vesicles, testes, and ovary is given by two-dimensional polyacrylamide gel electrophoresis, immunoblotting ("Western technique") of one-dimensional gels, and its concentration measured by reverse phase high performance liquid chromatography. The distribution within several parvalbumin-positive organs was monitored by the immunohistochemical peroxidase-antiperoxidase method. In teeth, only ameloblasts reacted with anti-rat parvalbumin serum and in bone the calcified extracellular cartilage was the target of the immunoreaction. The panniculus carnosus was the exclusive site of parvalbumin in the skin. Besides the already known parvalbumin distribution in the brain, parvalbumin is also expressed in distinct cell types of the peripheral nervous system. Leydig cells were found to be the only parvalbumin location in testes. These observations lead us to conclude that parvalbumin in contrast to the multifunctional and constitutive calmodulin must function in Ca2+-dependent processes related to specific cell types.

Animals↗
PubMed1984

Vitamin-D-dependent calcium-binding-protein and parvalbumin occur in bones and teeth.

Vit-D-Dependent calcium binding protein and parvalbumin have both been detected in ameloblasts and calcified cartilage by immunohistochemical techniques. These two Ca2+ binding proteins may play a crucial role in the local accumulation of Ca2+ ions during the process of mineralization. The mechanisms underlying the deposition of inorganic substances in bone and teeth during physiologic calcification are still the object of intense debate [1, 2]. The hypotheses concerning the factors controlling the initiation of mineralization can be subdivided into three large categories: enzymatic (or non-enzymatic) local elevation of phosphate and calcium [3,4,5,6,7], enzymatic removal of inhibitors of calcification [8] and direct nucleation of CaPO4 crystals on collagen fibrils [9]. In support of the first line of thought we report here the simultaneous occurrence of two different very high affinity Ca2+ binding proteins [vitamin-D-dependent CaBP = VD CaBP and parvalbumin = PV] in bones and teeth. During the studied age period and with immunohistochemical methods, we detected the proteins only in calcified cartilage of bones and in ameloblasts of teeth. We propose that VDCaBP and PV help increase the Ca2+ concentration at the calcification front in some regions involved in mineral deposition.

Animals↗
PubMed1983

A new myofibrillar protein characteristic of type I human skeletal muscle fibres.

Analysis of a single human type I (slow-twitch) skeletal muscle fibres by two-dimensional gel electrophoresis shows that they contain a specific protein of subunit Mr 34 x 10(3) and pI 6.0, 6.1 and 6.2 (three spots) which is absent from type IIA and IIB muscle fibres. This type I protein is located in the I-band of isolated myofibrils as demonstrated by the indirect immunofluorescence using specific antisera against the denatured form of type I protein. Type I protein could only be extracted from myofibrils with high salt solutions (0.6-1 M KCl), conditions which also coextract actin and myosin, demonstrating its firm attachment. Rat and cat type I muscle fibres as well as the slow-tonic fibres from chicken anterior latissimus dorsi also contained a protein homologous to the human type I protein. The human type I protein was found to be different from the known regulatory and contractile muscle proteins by electrophoretic and immunological criteria, and may therefore be a new myofibrillar protein in type I muscle fibres.

Animals↗
PubMed1983

Local generation of angiotensin in the kidney and in tissue culture.

The renin-angiotensin system is an exception among the various peptide hormone producing mechanisms in that it is an extracellular system. It was not clear whether renin in tissues other than kidney participates in the extracellular system or an intracellular mechanism. We examined the possibility of intracellular formation of angiotensin II in these tissues by using cloned, renin containing cells in culture as models. Neuroblastoma cells, pheochromocytoma cells, adrenal cortical cells and juxtaglomerular cells were shown to contain renin, angiotensin I and angiotensin II. Presence of angiotensin I converting enzyme was also demonstrated in some cell lines examined. Even juxtaglomerular cells in the intact kidney were shown to contain angiotensin I and angiotensin II by immunohistochemical technique. These findings indicate an intracellular mechanism of angiotensin II formation in various tissues and suggest that angiotensin II may have local paracrine functions.

Adrenal Cortex↗
PubMed1982

Monoclonal antibodies directed to human insulin-like growth factor I (IGF I). Use for radioimmunoassay and immunopurification of IGF.

Mouse hybridomas secreting antibodies to human insulin-like growth factor I (IGF I) were produced by fusion of spleen cells of hyperimmunised mice with FO mouse-myeloma cells. Eight clones producing antibodies against human IGF I have been isolated, two of which have been characterised. One was used in a radioimmunoassay, the other for immunopurification of IGF.

Acromegaly↗
PubMed1982

Angiotensin II immunoreactivity coexisting with renin in the human juxtaglomerular epithelioid cells.

The various components of the renin-angiotensin system in the human kidney have been detected by immunohistochemical techniques using specific antisera. Renin and AII immunoreactivities coexist in the JEG cells of the adult human kidney. I propose that AII is synthesized intracellular in the JEG cells of the human kidney and is secreted locally in the juxtaglomerular region, affecting the width of the glomerular arterioles and the contraction state of the glomerular mesangium.

Angiotensin II↗
PubMed1981

Renin in the human kidney. Immunohistochemical localization.

We have localized the enzyme renin (EC 3.4.99.19) in the normal adult human kidney by immunohistology. Serial paraffin sections of kidneys were incubated with renin antisera and then processed by the peroxidase-antiperoxidase method. Renin immunoreactivity was observed in the juxta-glomerular "epithelioid granular cells" (JEG-cells) in the wall of the afferent and rarely of the efferent vessel of the glomerulus. JEG-cells have long cytoplasmic processes penetrating between adjacent cells. This suggests a possible paracrine release of renin. Staining of various segments of the tubular system was shown to be artifactual. The kidney proteins recognized by our anti-human renin antisera had similar characteristics to renin when determined by a combination of gel-electrophoretic and immunologic techniques. Renin immunostaining in the juxtaglomerular apparatus of the human kidney is discrete and reflects the low amount of extractable renin.

Adult↗
PubMed1981

Angiotensin II immunoreactivity coexists with renin in the juxtaglomerular granular cells of the kidney.

The multiple physiologic functions of angiotensin II(AII) are generally supposed to be mediated by the peptide generated in the blood circulation. In addition to this extracellular mechanism of AII formation, we have obtained immunohistochemical evidence for the intracellular synthesis of AII in the kidney. Rats were perfused with fixative, and paraffin sections of the kidneys were processed with antisera against renin (EC 3.4.99.19), AII, and other components of the renin--angiotensin system. Renin immunoreactivity was regularly observed in the epithelioid granular cells in the media of the afferent vessel of the glomerulus. AII immunoreactivity was found to coexist within the same cells. This observation points to an intracellular production of AII in the juxtaglomerular epitheloid granular cells. AII may then be released concomitantly with renin in the interstitial fluid and in the blood. The paracrine secretion of AII could exert a local regulatory influence on the tonus of the glomerular vessels.

Angiotensin II↗
PubMed1980

Immunohistochemical localization of renin in mouse brain.

Immunohistochemical studies of mouse brain by the peroxidase-antiperoxidase method using monospecific antimouse renin antibodies has revealed the intracellular localization of renin in stellate and small ovoid cells. Renin-containing ovoid cells were observed in the spinal cord, medulla oblongata, pons, granular layers of the cerebellum, deep cerebellar region, and the lamina terminalis; whereas immunostainable stellate cells were found in the cerebral cortex, hippocampus, dentate gyrus and septum. Intracellular localization of renin rather than intravascular localization supports an endogenous origin of this enzyme in the brain. Wide distribution in different types of cells suggests different types of regulatory mechanisms. Double immunostaining with antigalactocerebroside and antirenin antibodies indicates the presence of renin in oligodendrocytes.

Animals↗
PubMed1980

Renin in rat and mouse brain: immunohistochemical identification and localization.

1. Localization of renin in rat and mouse brain was determined by immunohistochemical methods with specific anti-renin antibodies. 2. Renin-containing neuronal cells were found in the medulla oblongata, cerebellar nuclei and hypothalamus. Purkinje cells contained renin. 3. Glia-like cells contained renin. Some of them are closely associated with vascular walls and these vascular walls were renin positive. 4. The pineal gland, adenohypophysis and choroid plexus contained renin. 5. The extensive distribution of renin suggests functions other than those which have been associated with the hypothalamus.

Animals↗
PubMed1980

'Proopiocortin fragments' in normal human adult pituitary. Distribution and ultrastructural characterization of immunoreactive cells.

The distribution and ultrastructure of cells immunoreactive towards antisera against synthetic fragments of proopiocortin were studied in human pituitaries by immunohistochemical methods. Anterior lobe cells exhibiting the ultrastructural characteristics of corticolipotropes, as well as all epithelial cells 'invading' the posterior lobe, display beta-endorphin/beta-lipotropin-ACTH immunoreactivities. At low dilution a beta-lipotropin antiserum, raised with highly purified antigen, stains also somatotropes. alpha-MSH antibodies bind to certain corticolipotropic cells in the pars distalis and to only a few of the cells 'invading' the pars nervosa. Met-enkephalin antisera react only with isolated cells in the anterior lobe. These results indicate a striking difference in the processing of the proopiocortin precursor molecule in different corticolipotropic cells of the human hypophysis. Furthermore, the hypothesis of a homology between cells 'invading' the human neurohypophysis and those of the intermediate lobe of lower vertebrates, is questioned.

Adrenocorticotropic Hormone↗