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PubMed1987

Ultrastructural organization of regenerated serotonin axons in the dorsomedial hypothalamus of the adult rat.

The ultrastructural organization of regenerated serotonin (5-HT) axons was examined in the dorsomedial hypothalamus (DMH) of the adult rat using high-resolution radioautography after intraventricular infusion of [3H]5-HT. An analysis of the microenvironment of the [3H]5-HT-labelled terminals in the DMH was made 30 and 50 days after unilateral injection of 5,7-dihydroxytryptamine (5,7-DHT) or vehicle solution into the dorsolateral hypothalamus. In sham-treated animals [3H]5-HT-labelled axons were small, contained many small clear vesicles, one or more large granular vesicles, and showed only rare synaptic specializations. In 5,7-DHT-treated animals the internal organization of [3H]5-HT-labelled profiles resembled that of sham-treated animals. A tendency toward increased synaptic frequency was found for [3H]5-HT-labelled terminals in the 5,7-DHT-treated group 50 days post-lesion, and an increase in the number of [3H]5-HT-labelled terminals abutting unlabelled perikarya was found in both 30- and 50-day post-lesion groups as compared to sham-treated groups. No other differences in ultrastructural environment were found between sham- and 5,7-DHT-treated animals at either 30 or 50 days post-lesion. These results suggest that 5-HT fibres in the hypothalamus regenerate with a great deal of cellular specificity.

5,7-Dihydroxytryptamine↗
PubMedDate not supplied

The microvascular response to growth factors in the hamster cheek pouch.

Implicit in attempts to characterize and purify biologically active factors is the premise that the bioassay system employed will show a progressive increase in the response as the concentration of the responsible factor increases. We employed the hamster cheek pouch to assay the neovascularization potential of growth factors, including endothelial cell growth supplement (ECGS), epidermal growth factor (EGF), fibroblast growth factor (FGF) and platelet-derived growth factor (PDGF). Each growth factor was applied to the system in graded concentration and two approaches used to assess neovascularization: first, direct serial inspection of the cheek pouches at 40 power; second, tritiated thymidine incorporation into endothelial cells, assessed by radioautography. PDGF induced a dose-related increase in neovascularization, with a threshold dose of 17.5 micrograms/ml and a peak, 56% response, at a PDGF concentration of 175 micrograms/ml. Progressive increases in PDGF concentration, thereafter, induced progressive reductions in the neovascularization rate. Under some conditions optimal bioassay requires serial dilutions of the assay material over a wide range.

Animals↗
PubMed1978

Ca2+ binding, ATP-dependent Ca2+ transport, and total tissue Ca2+ in embryonic and adult avian dystrophic pectoralis.

Avian muscular dystrophy is an autosomal recessive genetic disease characterized by early hypertrophy and loss of function of pectoralis major. The disease is progressive, ultimately resulting in atrophy and heavy lipid deposition. Previous investigators have noted a decrease in the ability of the dystrophic sarcoplasmic reticulum to concentrate Ca2+. More recently, other investigators have shown an abnormal calcium uptake in avian dystrophic sarcoplasmic reticulum. They indicated, using freeze-fracture techniques, that a 90 A particle of the vesicle membrane exhibited a decreased population and suggested that they might be the ATPase involved in calcium transport. Our studies confirm earlier observations of a decreased rate of Ca2+ uptake and Ca2+ binding capacity of dystrophic fragmented sarcoplasmic reticulum vesicles which are isolated from both embryonic and adult pectoralis. These observations correlate in turn with a 75% drop in the Ca:ATP transport efficiency of the dystrophic sarcoplasmic reticulum determined by measuring the rate of 32Pi liberation from gamma-ATP32 during active calcium transport by the isolated sarcoplasmic reticulum SR. In addition, we have found a quantitative deficiency in a 65,000 dalton component of the dystrophic fragmented SR at the time of myoblast fusion by measuring 35S-Methionine incorporation into the SR, coupled to high resolution polyacrylamide gel electrophoresis and radioautography. Analysis of total tissue calcium by atomic absorption spectroscopy revealed a decrease in the total calcium content of dystrophic muscle.

Adenosine Triphosphate↗
PubMed1975

Ferritin synthesis by splenic tumor tissue of Hodgkin's disease.

Increased ferritin synthesis by Hodgkin's disease splenic tumor tissue was demonstrated by incorporation of 14C-leucine and radioautography. This suggests that elevated tumor and serum ferritin concentrations found in patients with Hodgkin's disease is derived from tumor tissue per se.

Adolescent↗
PubMed1984

Cellular distribution of dexamethasone in rabbit spleen and lymph nodes.

The binding of tritiated dexamethasone by rabbit spleen and lymph nodes was studied in vivo by dry radioautography. The labeled glucocorticoid was found in the surface and cytoplasm of eosinophil leukocytes and in the nuclei of reticular cells, plasmocytes, endothelial cells and macrophages, but not in lymphocytes, lymphoblasts or plasmoblasts. Additional administration of excess of excess of non-radioactive dexamethasone suppressed this labeling. The findings are discussed in relation to the mechanism of action of glucocorticoids in lymphoid organs.

Animals↗
PubMed1985

The enteric neural receptor for 5-hydroxytryptamine.

An enteric neural receptor for serotonin (5-HT) has been characterized. This receptor was assayed, using 3H-5-HT as a radioligand, by rapid filtration of isolated enteric membranes and by radioautography. In addition, intracellular recordings were made from ganglion cells of the myenteric plexus. High affinity, saturable, reversible, and specific binding of 3H-5-HT was demonstrated both to membranes of the dissected longitudinal muscle with adherent myenteric plexus and the mucosa-submucosa. Radioautographs showed these 3H-5-HT binding sites to be in myenteric ganglia and in a broad unresolved band at the mucosal-submucosal interface. Antagonists active at receptors for other neurotransmitters than 5-HT, at either of the two known types of CNS 5-HT receptor, and at 5-HT uptake sites on serotonergic neurons failed to inhibit binding of 3H-5-HT. The structural requirements of analogues for binding to the enteric 5-HT receptor matched the known pharmacology of M or neural 5-HT receptors. A novel 5-HT antagonist was found. This compound, N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide (5-HTP-DP), antagonized the action of 5-HT on type II/AH cells of the myenteric plexus but did not affect the release or actions of acetylcholine (nicotinic or muscarinic) or substance P. 5-HTP-DP was also an equally potent displacer of 3H-5-HT from its binding sites on enteric membranes. It is concluded that the sites responsible for specific binding of 3H-5-HT are enteric M or neural 5-HT receptors. These receptors differ from those now known to be present in the CNS.

5-Hydroxytryptophan↗
PubMed1986

Development of traction retinal detachments following intravitreal injections of retinal Muller and pigment epithelial cells.

We injected varying numbers of retinal Muller glia into the rabbit vitreous in an established model of traction retinal detachment. We used indirect ophthalmoscopy to observe the changes elicited during the following 1 month. Although the severity of the tractional changes increased with increasing numbers of the glial cells, the pathology produced stabilized within the 1st week of injury. Muller glia were less effective at eliciting retinal detachments than retinal pigment epithelial cells (RPE) or mixtures of glia and RPE. Intravitreal tissue membranes derived from the glia differed morphologically from those derived from RPE. The glial membranes had fewer fibroblast-like cells, synthesized less extracellular matrix, and showed lower intravitreal cell proliferation, as determined by 3H-thymidine radioautography. Our findings indicate that membranes composed only of Muller glial cells promote less severe retinal pathology than those membranes composed of RPE or mixed cell types.

Animals↗
PubMed1992

Molecular neuroanatomy of monoamine oxidases in human brainstem.

Specific, high-resolution techniques (quantitative enzyme radioautography and in situ hybridisation histochemistry) have revealed distribution, abundance and cellular localization of the isoenzymes MAO-A and MAO-B and their mRNAs in human post-mortem brainstem. Whereas MAO-A protein and mRNA are expressed by noradrenergic neurons of the locus coeruleus, MAO-B protein and mRNA are expressed by serotoninergic neurons of the raphé nuclei. In the substantia nigra, MAO-B was more abundant than MAO-A; the former was localized in the reticular zone and the latter in the compact zone (where melanin-containing dopaminergic neurons are found). To date, it has not been possible to detect mRNA for either MAO-A or MAO-B in the substantia nigra or in glial cells of the brain regions investigated, suggesting either that the technique has limited sensitivity, or the possible existence of MAO-A and MAO-B subtypes.

Aged↗
PubMed2001

Localization of specific binding sites for 125I-TGF-beta1 to fenestrated endothelium in bone and anastomosing capillary networks in enamel organ suggests a role for TGF-beta1 in angiogenesis.

Previous studies have shown endothelial cells to be a major target for endocrine TGF-beta in several soft tissues in the normal growing rat. The potent effect of TGF-beta1 on bone formation prompted us to analyze in detail the localization of specific binding sites for endocrine TGF-beta in hard tissues. At 2.5 minutes after injection of 125I-TGF-beta1, specific binding, as demonstrated by quantitative radioautography, was localized to fenestrated endothelium participating in angiogenesis in the vascular invasion region of the growth plate in bone as well as to anatomizing capillary networks in the maturation zone of the enamel organ. At 15 minutes after injection, the bound ligand was internalized into endocytic vesicles of endothelial cells. In bone, quantitation revealed significant differences in receptor density between endothelia undergoing proliferation vs those in a state of elongation and anastomosis with neighboring endothelial cells. In the rat incisor, specific binding of 125I-TGF-beta1 to endothelium correlated with increased formation of anastomotic capillary networks. These studies identify differential specific binding sites of 125I-TGF-beta1 in angiogenically active endothelium, providing an important link between TGF-beta1, the endothelium, and hard tissue development.

3T3 Cells↗
PubMed1983

Zonal analysis of cytoplasmic steroid hormone receptor levels: replication and synthetic activity in embryonic calf growth cartilage.

Using the dextran charcoal method, a specific steroid receptor for dexamethasone, but not 17 beta-estradiol or 17 alpha-methyltrienolone, was demonstrated in cytosol prepared from mid-gestation fetal calf growth cartilage. Zonal analysis of cytoplasmic receptor levels showed that tissue sections from the center, the peripheral surface, and the palisade section bound 229 +/- 111, 173 +/- 64, and 15 +/- 28 femtomole dexamethasone per mg of protein, respectively. Incorporation of 3H-thymidine, 35S-sulfate, and 3H-proline into cartilaginous tissues was used as an index of replication and synthetic activity. The percentage of 3H-thymidine labeled nuclei, as determined by radioautography, showed that the palisade zone has a significantly lower replicating activity (P less than 0.001). Values were 5.6 +/- 1.2, 5.4 +/- 1.2, 3.8 +/- 1.3, and 1.1 +/- 0.2 for the center, peripheral surface, and upper and lower half of the palisade section. The rate of sulfate and proline incorporation into the palisade zone was over seven times higher than the central and peripheral surface (P less than 0.001). The difference in the rate of matrix synthesis and proliferating activity in these regions may be related to the zonal heterogeneity of receptor levels of glucocorticoids in fetal growth cartilage.

Animals↗
PubMed1984

Comparative radioautographic study of the effects of L-azetidine-2-carboxylic acid on matrix secretion and Golgi of the mouse incisor.

The effect of a proline analog, L-azetidine-2-carboxylic acid (LACA), on protein matrix secretion by odontoblasts and ameloblasts was compared by light and electron microscopic radioautography after injection of 3H-glycine in young mice. LACA inhibited the secretion of dentin matrix with consequent accumulation of 3H-glycine labeled procollagen in the cisternae of the rough endoplasmic reticulum. In contrast, LACA had no apparent effect on ameloblasts as enamel matrix continued to be packaged in the Golgi apparatus and secreted from Tomes' process within 30 min after injection of the radioprecursor. Electron microscopy revealed that LACA did not cause any change in ameloblast ultrastructure but produced a marked alteration of the odontoblast Golgi complex. All odontoblast Golgi saccules and collagen secretion granules disappeared within 2 h after LACA administration. Odontoblast Golgi cisternae, however, appeared not to be affected. These observations confirm previous studies conducted in this laboratory showing that Golgi saccules in collagen-secreting cells are the initial staging areas for the formation of secretory granules. These results also indicate that a close correlation exists between form and function in the Golgi apparatus of collagen-secreting cells.

Ameloblasts↗
PubMed1977

In vitro binding of 3H-estradiol to eosinophil and neutrophil granulocytes in various tissues (normal and neoplastic) of newborn and adult rats.

In vitro uptake and binding of tritiated estradiol to the specific granules of eosinophil granulocytes has been observed by ultrastructural radioautography in various tissues of the rat (liver and spleen of newborn, small intestine and bone marrow of adult animals). Binding of 3H-estradiol to granules present in the cytoplasm of neutrophil granulocytes has also been observed in bone marrow and in a cholangioma produced by chemical carcinogenesis. Neither type of granulocyte bound 3H-testosterone.

Adenoma, Bile Duct↗
PubMed1982

In vivo incorporation of 3H-choline in alveolar type-II pneumocytes in mice treated with butylated hydroxytoluene (BHT).

Butylated hydroxytoluene has been previously shown to damage alveolar type-I cells followed by proliferation of type-II pneumocytes which then redifferentiate into intermediate and newly formed type-I epithelial cells. In relation to this transformation process, in vivo incorporation of H3-choline, a precursor of the main component of lung surfactant, was studied in type-II cells of BHT-treated mice by electron microscopic radioautography. The labeling density was reduced in some type-II cells at 2, 3 and 5 days after a single injection of BHT. Cellular compartment analysis indicated that the transformation of type-II cells is accompanied by a notable loss of their lamellar body component as well as a decreased radioautographic labeling associated with this cell type, possible in relation with modified synthesis of phospholipid material of surfactant.

Animals↗
PubMedDate not supplied

Percutaneous absorption of 14C-labelled 2-chlorobenzaldehyde in rats. Metabolism and toxicokinetics.

2-Chlorobenzaldehyde might be produced when a moist skin is exposed to the riot control agent CS. CS-hydrolysis to 2-chlorobenzaldehyde and malononitrile occurs both in vitro and in vivo. No quantitative data have thus far been reported with respect to the percutaneous absorption and the cutaneous biotransformation of 2-chlorobenzaldehyde. Percutaneous absorption, biotransformation and elimination of 14-C-labelled 2-chlorobenzaldehyde was investigated in the rat. Following IV (25 microliters/kg) and IP (37.5 microliters/kg) 14C-2-chlorobenzaldehyde administration to rats, the plasma radioactivity declined rapidly over a 24 h period with similar plasma radioactivity-time profiles. Following cutaneous administration (75 microliters/kg) in a closed glass-cup on the skin a slow skin penetration occurred as indicated by plasma radioactivity levels. A slow increase in plasma radioactivity was followed by a slow decline of radioactivity in plasma over a 3-day period. Most of the radioactivity was found in the urine with low levels in faeces and exhaled air. The cutaneously administered radioactivity was also partly recovered from the glass-cup. For the qualitative and quantitative determination of metabolites in urine, a thin layer chromatography-radioautography method was used. The metabolic patterns of urinary excreted metabolites following cutaneous application and systemic administration of 14C-2-chlorobenzaldehyde to rats were very similar. No parent compound was recovered from the rat urine. 2-Chlorohippuric acid was the principal urinary metabolite. Quantitatively, the urinary excretion of 14C-2-chlorobenzyl alcohol following cutaneous application differed substantially from that after the systemic administration. There was no evidence of storage in the skin or skin toxicity of 2-chlorobenzaldehyde following cutaneous application.

Animals↗
PubMed1999

Development of glomerular synaptic complexes and immunohistochemical differentiation in the superficial dorsal horn of the embryonic primate spinal cord.

Development of glomerular synapses in the superficial dorsal horn has been studied in the embryonic macaque spinal cord using light and electron microscopic techniques including Golgi impregnation, 3H-thymidine radioautography and pre-embedding immunohistochemistry of substance P (SP), calcitonin gene related peptide (CGRP), calbindin D-28 K (CB) and parvalbumin (PV). The study revealed that substantia gelatinosa cells of the primate dorsal horn are generated last, but unlike in rodents, synaptogenesis in this region starts at early embryonic (E) stages of the 165-day long gestation. Already by E30, both Type 1 (light) and 2 (dark) dorsal root axons and their growth cones are identifiable within the oval bundle of His, before they form synaptic contact with their final target cells. Subsequently they invade the dorsal horn and enter the bisecting interfaces formed by orderly programmed cell death. Each type of scalloped (sinusoid) central primary afferent terminal (i.e. DSA, RSV and LDCV) have well defined pre- and post-synaptic specializations already by E40. Among the neuropeptides studied, SP appears first at E67 and CGRP at E70 in the lateral position but within a few days both of them are spread to the entire superficial dorsal horn. Both SP and CGRP are present in the thin dorsal root axons and their growth cones, giving rise to scalloped and simple axon terminals. PV is transiently present in the entire length of the thick dorsal root afferents before becoming concentrated in the synaptic boutons. CB is displayed mainly in neurons of the lamina I and III. Dendrites of CB-immunoreactive cells establish synaptic connection with each type of dorsal root afferents, including glomerular synaptic complexes. These data reveal that the superficial dorsal horn in the primate spinal cord develops its characteristic synaptic complexes much earlier in gestation than in any other mammalian species studied. Furthermore, characteristic cytological features of the prospective glomerular complex emerge before establishment of the final synaptic contacts.

Animals↗