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PubMed1979

The visual system of the trout Salmo irideus Gibb. A degeneration and radioautographic study.

The organization of the primary visual system of the trout (Salmo irideus Gibb.) was studied by Fink-Heimer methods and radioautography. In addition to normal fiber, Nissl and Golgi staining techniques, we carried out total ablation of the retina on the right side on 16 animals which survived post-operatively at 13 degrees C for 9 to 31 days. The brains were cut at 35 micrometer and then stained by the Fink-Heimer techniques. Furthermore, we injected 20 microliter (2 microCi) of 14C proline into the right eye of 8 trouts which were then fixed between 24 and 72 hours after the injection, and then prepared for radioautography. The primary visual system projections are entirely contralateral. The optic tract is divided into three bundles which pass into tectal layers 2, 4 and 6. In the trout, a very obvious deep optic layer is present which extends throughout the length of the medial part of the tectum. In addition to the accessory optic tract and to a projection at the level of the preoptic area, the trout possesses a well-developed thalamic visual system composed of a ribboned geniculate nucleus and two medial thalamic visual centres fed by the retinothalamic pathways as well as a small retinal target located in the lateral thalamus. The pretectum receives only a few small sparse retinal projections. An interpretation of the trout visual system as the whole is discussed.

Animals↗

PubMed1981

An electron microscopic radioautographic identification of the APUD endocrine cells in the rat gastric pyloric glands.

The rat stomach was shown some years ago to contain numerous endocrine cells with APUD ability--cells that could take up the amino acids L-5-hydroxytryptophan (5-HTP) or L-dihydroxyphenylalanine (L-DOPA) and could decarboxylate them to their respective amines, 5-hydroxytryptamine (5-HT, serotonin) and dopamine, by means of the enzyme DOPA-decarboxylase. In a recent study, most of the APUD endocrine cells in the rat oxyntic mucosa were shown by electron microscopic radioautography to be the enterochromaffinlike cells, while the A-like cells were shown to lack APUD ability. To identify the APUD cells in the pyloric mucosa, pieces of rat pylorus were incubated in organ culture with 3H-5-HTP and were processed for light microscopic and electron microscopic radioautography. Additional specimens were incubated with 3H-5-HTP and carbidopa, an inhibitor of DOPA-decarboxylase, used to block the decarboxylation of 3H-5-HTP to 3H-5-HT, or with 3H-5-HT, used to determine where exogenous 3H-5-HT localizes in the pyloric mucosa. The 3H-5-HTP labeled all three types of endocrine cells identified within the pyloric glands--the G, enterochromaffin, and D cells. As this labeling was inhibited by carbidopa, and as exogenous 3H-5-HT labeled these cells only lightly, the labeling must have resulted from the uptake and intracellular conversion of the 3H-5-HTP of 3H-5-HT. Thus despite their morphologic differences, all rat pyloric endocrine cells possess APUD ability, a property shared by many, but not all, of the peptide- and amine-producing endocrine cells located throughout the body.

5-Hydroxytryptophan↗

PubMed1984

[New data on the histogenesis of connective tissue tumors].

The normal skin and adipose subcutaneous tissue, desmoid fibroma, lipomas with varying proliferative activity, fibrosarcoma, malignant fibrous histiocytoma, epithelioid leiomyoma are studied by means of electron microscopy and electron microscopical radioautography. It was found that the walls of the smallest vessels contain cells which are the source of a permanent physiological renewal of a different type of the connective tissue. In proportion to differentiation and gradual removal of these cells from the vascular wall their proliferative and metabolic activity is more and more decreasing. Thus, the vessels represent not only the transport-nutritive system but the central generative structure of the connective tissue as well. Pluripotential mesenchymal cell of the vascular wall which under physiological conditions is differentiating in the direction of fibro-, angio-, lipo- or osteogenesis, due to the influence of oncogenic factors gives rise to the development of benign and malignant tumours of fibrous, vascular (angiomas), smooth muscle, adipose and bone structure. This can be most demonstratively checked using electron-radioautography of tumourlike conditions and relatively slow growing tumours.

Adipose Tissue↗

PubMed1984

Activity and the formation of ocular dominance patches in dually innervated tectum of goldfish.

This study tested (1) whether blocking impulse activity in both eyes of fish with one tectum prevents the formation of ocular dominance patches, (2) whether areas receiving a high density of innervation from one eye receive a low density from the other, and (3) whether there is an electrophysiological correlate to the anatomical patches. One tectum was removed in goldfish so that the optic nerve fibers from both eyes would compete for synaptic space in the remaining tectum. The terminal arbors from the two projections initially overlapped but by 50 to 60 days segregated into ocular dominance patches, demonstrated by labeling both projections, the normal one with horseradish peroxidase and the regenerating one with tritiated proline radioautography. Alternate sections were processed for radioautography and histochemistry. All projections were drawn by "blind" observers using a camera lucida and were fully reconstructed. Both the level of patchiness within each projection and the correspondence of patches and holes between the two projections were quantified from these reconstructions. Binocular tetrodotoxin (TTX) injections from 18 to 75 days after surgery significantly reduced patchiness, as compared to controls injected with citrate-Ringers solution. When the binocular block was continued until 95 days, segregation was still significantly reduced relative to controls. These results support a hypothesis for an activity-dependent mechanism of segregation of ocular dominance patches. In controls but not TTX-blocked fish, there was a significant tendency for high density areas in one projection to receive a lower density projection from the other eye, and vice versa. However, the two projections were not entirely complementary. Survival of control fish for an additional 5 months resulted in more sharply defined patches but no increase in complementarity. Recordings of field potentials evoked by shocking either optic nerve demonstrated an electrophysiological correlate to the anatomical patches in single tectal fish. Large field potentials from one eye were generally associated with small potentials from the other eye, and vice versa. When the recording sites were marked with electrolytic lesions, there was a direct and significant correlation between the magnitude of the field potentials and the density of the anatomical ocular dominance patches.

Animals↗

PubMed1983

High-resolution radioautographic study of dopamine binding sites in the rat neostriatum using 3H-domperidone.

The possibility to use the new ligand 3H-domperidone to identify some dopamine binding sites at the ultrastructural level was assessed in the neostriatum after in vivo administration and high-resolution radioautography. Since this ligand does not cross the blood-brain barrier, intracerebral injections were performed, which resulted in a gradient of diffusion of the tracer. According to increasing distances to the injection site, a quantitative study of the radioautographic reaction was realized. An intense and diffuse reaction took place in the vicinity of the injection site in control rats. On the contrary, numerous accumulations of silver grains were observed in the peripheral zone. The statistical analysis of the distribution of the clusters showed that they were more numerous over the contacts between nerve terminals and dendritic spines than expected from a distribution at random; moreover half of these labelled contacts were differentiated in synapses of the asymmetric type. When the animals were pretreated with haloperidol in order to block the dopaminergic binding sites, we found a decrease in the total number of the number of silver grains. A decrease in the number of clusters of silver grains was noted over nerve terminals and synaptic contacts in both peripheral zones while the nonspecific labelling was increased over other structures. We conclude to the possibility of the detection of the dopaminergic binding sites by electron microscopic radioautography. Moreover we confirm the existence of dopaminergic synapses in the neostriatum with this new technique.

Animals↗

PubMed1983

Electron microscopic radioautographic localization of iodinated nerve growth factor bound to and internalized by PC12 cells.

Nerve growth factor (NGF) has many effects on sympathetic and sensory neurons, but the mechanisms by which NGF exerts its actions are unknown. We have determined the localization of bound and internalized 125I-NGF by light and electron microscopic radioautography on a cell line derived from a rat pheochromocytoma (PC12). In response to NGF, PC12 cells cease mitosis and develop neuron-like processes. We have localized 125I-NGF (5 ng/ml) in cells without previous exposure to NGF (naive) after a continuous incubation with 125I-NGF for 2 min, 1 hr, 6 hr, 1 day and 1 week, as well as in cells that were grown with NGF (50 ng/ml) for 1 week (primed) and then exposed to 125I-NGF for 15 min, 1 hr, 6 hr, and 1 day. Examination of whole mount radioautographs revealed that all cells were labeled and that the distribution of grains was homogeneous. Primed cells were labeled on neurites and growth cones, as well as on cell bodies, and also had a greater density of labeling than naive cells. These patterns were identical for all time points studied, with the exception that "hot spots" of radioactivity appeared along neurites following a long incubation with 126I-NGF (longer than 6 hr). Electron microscopic radioautography revealed that these "hot spots" correspond to accumulation of grains in aggregates of lysosomes. The binding of 125I-NGF was specific, since control cultures (excess nonradioactive NGF) exhibited only background levels of grains. Quantification of electron microscopic radioautographs revealed that 70 to 95% of the grains were internalized after 15 min. The only cellular components labeled above random distribution levels were the plasma membrane, lysosomes, and the nuclear membrane. Each of these structures exhibited "down-regulation" of specific binding in naive cells after 6 hr of incubation. The cytosol, polyribosomes, dense cored granules, heterochromatin, and euchromatin showed labeling at or below the levels expected from random distribution of grains within the cell. The distribution of grains about the nuclear membrane also suggested an association with 125I-NGF. These data indicate that a large proportion of NGF "bound" to target cells is in fact internalized, and are consistent with some, but not other models for NGF's mechanism of action.

Adrenal Gland Neoplasms↗

PubMed1983

[Retinotopic projections of the trout (Salmo gairdneri)].

The retinotopic organization of the thalamic and tectal and visual centres was studied by Fink and Heimer method and radioautography. Quadratic lesions were achieved in the right retina of 21 adult trouts and 23 six month old specimens. Fourteen animals (adults) were kept alive for 20 to 25 days after operation, in running water at 13 degrees C and prepared for the Fink technique. In the remaining 7 adults and in the 23 six month specimens, we injected, 48 hours after the lesion, respectively, 2,5 microCi (in 20 microliters) and 0,5 microCi (in 1 microliter) of 14 C proline into the operated eye. The brains were prepared for radioautography. Results show that the thalamic pathways is not correlated with a peculiar quadrant. Nevertheless the temporo dorsal hemiretina sends the more numerous projections at this level. A topographic parallelism exists between retino-geniculate and retino-tectal projections. At the tectal level our data are somewhat at variance with those of electrophysiological mapping, since quadratic projections show a partial overlapping. In the optic tract, the fibres from every quadrant follow always the same pathway.

Animals↗

PubMed1981

The effects of naturally occurring bisdihydrofuran ring-containing mycotoxins on cultured chick embryonal hepatocytes.

The cytotoxicity of 16 naturally occurring mycotoxins which contain the bisdihydrofuran ring was evaluated by electron-microscopy and radioautography in a primary culture of chick embryonal hepatocytes. A series of nucleolar changes occurred, including the appearance of microsegregation (stage I), concentration of nucleolar structure (stage II), formation of macrosegregation, fragmentation of nucleoli, and the appearance of homogeneously granular nucleoli (stage III). These nucleolar changes correlate well with the inhibition of RNA synthesis calculated from the results of radioautography. The compounds containing a 2,3-double bond in the bisdihydrofuran ring were most toxic. However, it was clear that there was a remarkable difference between mycotoxins of angular type (group A) and those of linear type (group C). Therefore, not only the active site in the molecule but also the shape of the molecule may play an important role in the cytotoxicity of these mycotoxins.

Aflatoxins↗

PubMed1994

Synaptic properties of serotonergic growth cones in developing rat brain.

In order to gain insight into the events that take place when serotonergic growth cones are remodeled into synapses, we tested the hypothesis that neurotransmitter-related properties of presynaptic terminals are already present in these growth cones before synaptogenesis begins. The ontogeny of markers for the specific reuptake of 5-HT and for 5-HT-storing synaptic vesicles was studied in isolated growth cone (IGC) fractions from developing rat brain. High-affinity 3H-imipramine binding (a marker for the plasma membrane 5-HT transporter) was significantly enriched in IGC fractions prepared before the beginning of cortical synaptogenesis [embryonic day 15 (E15) and E20]. Radioautography with 3H-imipramine or 3H-paroxetine (another marker for the transporter) confirmed that the 5-HT transporter is present in the cerebral cortex when it contains serotonergic growth cones, but not serotonergic synapses. Specific uptake of 3H-5-HT was found in IGC fractions as early as E15; this uptake was inhibited by fluoxetine. Electron microscopic radioautography demonstrated directly that growth cones were the structures in IGC fractions that took up 3H-5-HT. The synaptic vesicle protein synaptophysin and a 45 kDa protein found specifically in serotonergic synaptic vesicles, serotonin-binding protein (SBP), were each enriched in IGC fractions from E15 to postnatal day 5; SBP immunoreactivity increased approximately 10-fold between E15 and E20. Endogenous 5-HT was detected in IGC fractions at E15 and increased in amount as development proceeded. The ratio of 5-HT to 5-hydroxyindole acetic acid suggested that 5-HT within growth cones is protected from catabolism by monoamine oxidase. Reserpine-induced depletion of 5-HT, a marker for the vesicular carrier of 5-HT, was apparent in IGC fractions at E20, but not at E15. These data suggest that properties that characterize the presynaptic components of mature serotonergic synapses develop in growth cones before synapses are formed. The early development of these properties may permit neurotransmission to be established rapidly during synaptogenesis or, alternatively, enable 5-HT to play a role in ontogeny.

Animals↗

PubMedDate not supplied

Morphologic and radioautographic studies of bone formation in relation to titanium implants using the rat tibia as a model.

A rat tibia model was developed to analyze bone formation leading to osseointegration with threaded titanium implants. Miniaturized titanium implants were placed in the anterior aspect of the upper tibia of rats weighing 350 g. Twenty-four rats were involved; 12 rats were sacrificed at 6 weeks, and another two rats were sacrificed weekly for 6 weeks following implantation. Four days prior to sacrifice, the animals were injected intraperitoneally with 3H-proline (10 microCi/g body weight). The rats were fixed by perfusion with 5% glutaraldehyde, and the tibia were decalcified and embedded in Epon. The implants were removed from the embedded bone by fracturing, and the specimens re-embedded. Sections were prepared for light and electron microscopy and radioautography. Morphologic observations indicated that implant placement resulted in bone necrosis and resorption. This was followed by bone growth from the old bone surfaces filling the threads with vascular channels and new lamellar bone. Osseointegration was complete at 6 weeks in all animals examined. Electron microscopy at various places along the bone-titanium interface showed an amorphous layer, a granular electron-dense layer, or a layer of uncalcified collagen fibrils. At each week after surgery, radioautography showed the position and thickness of new bone labeled with 3H-proline during the last 4 days. Radiolabeled new bone was deposited only on previously existing bone and extended toward the available space. Since there was no apparent relationship between the implant and the new bone, it was suggested that titanium is biocompatible, but not necessarily osteoinductive.

Animals↗

PubMed1993

Radioautographic study on the intracellular localization of a hypolipidemic agent, bezafibrate, a peroxisome proliferator, in cultured rat hepatocytes.

In order to demonstrate the intracellular localization of the peroxisome proliferator in the hepatocytes, we have examined the localization of silver grains due to 14C-labelled bezafibrate in cultured rat hepatocytes by means of light and electron microscopic radioautography. As it results from the difference between chemical fixation and freeze-substitution by light microscopic radioautography, more numerous silver grains, about twice, were observed in freeze-substitution specimens in comparison with chemical fixation. On light microscopic radioautograms of the epoxy resin sections during each experimental condition, about 90% of all the silver grains were localized over the cytoplasm. Then, statistical significance was evaluated on grain density in the cytoplasm. On electron microscopic radioautograms of whole mount cultured cells, silver grains were localized not on the peroxisome but on the cytoplasmic matrix specially over the endoplasmic reticulum. From these results, it is concluded that bezafibrate was localized over endoplasmic reticulum. This fact suggests that the receptor of the peroxisome proliferator should be associated with the endoplasmic reticulum or that the receptor exists on the endoplasmic reticulum. Thus, it is demonstrated that the peroxisome proliferator acts on the endoplasmic reticulum of hepatocytes to proliferate peroxisomes.

Animals↗

PubMed1993

Radioautographic study on the aging change of 3H-glucosamine uptake in mouse ileum.

The changes of the localization of incorporated glucosamine in mice ilea due to aging were studied by light microscopic radioautography in 10 groups of mice from fetus (19th day of embryo) to senescent (postnatal 2 years). After intraperitoneal injection of 6-3H-D-glucosamine the ilea of respective age groups were taken out and processed for light microscopic radioautography. The numbers of silver grains were counted at each part of ileal mucosal cells. The results show that the silver grains of columnar epithelial cells were localized mainly on brush border and Golgi region, and the grains of goblet cells were localized on Golgi region and mucous granules. Comparing the intestinal villi and crypts, the uptake of columnar epithelial cells and villi goblet cells was higher than these cells in crypt. The number of grains in respective age groups increased from perinatal to mature adults due to aging.

Aging↗

PubMed1993

Light microscopic radioautographic study of DNA synthesis in the kidneys of aging mice.

The change of proliferative activity in mouse kidney cortex cells during development and aging was studied by detecting S-phase cells by light microscopic radioautography using 3H-thymidine (3H-TDR). Mouse kidney tissues of various ages: prenatal 13.5, 15.5 and 19.0 days of gestation, postnatal 1 and 8 days, 1 and 2 months, and 1 year were used for this experiment. The kidney cortex tissues were labelled with 3H-TDR either in vitro or in vivo and they were processed for light microscopic radioautography. The labeling indices of the respective cell types were calculated. The labeling indices in glomeruli and uriniferous tubules in the superficial layer were higher than those in the deep layer of metanephric cortex through the developmental stages. However, they decreased rapidly after birth and reached low levels (below 4%) from 1 day to 1 year.

Aging↗

PubMed1997

[The cytological aspects of chronic pancreatitis].

Biopsy material of pancreatic tissue using light-optical radioautography and electron microscopy, and the method of high-precise radioautography also, was investigated to study up the pancreatic gland (PG) pathology in chronic pancreatitis (CHP). It was established that CHP is a chronic proliferative-destructive process causing focal generalized fibrosis of PG. All the structural components of organ, and the duct epithelium first of all, are affected in CHP. It gives reason to regard a duct system as a complex independent morphofunctional unit of PG.

Autoradiography↗

PubMed1965

THE SEQUENTIAL SYNTHESIS OF THE POLYPEPTIDE CHAIN OF SERUM ALBUMIN BY THE MICROSOME FRACTION OF RAT LIVER.

1. The isolated microsome fraction of regenerating rat liver was incubated with cell sap, a source of energy and [(35)S]methionine, [(14)C]isoleucine or [(14)C]leucine for different periods of time, and microsomal albumin isolated. 2. The distribution of these isotopes in albumin was determined by separation of tryptic peptides from the protein. Radioactivity was measured in peptides either qualitatively by radioautography or quantitatively by labelling with both (3)H and (14)C. 3. A gradient of radioactivity existed at all times in albumin isolated after incubating microsomes. 4. The shorter the incubation time the fewer the peptides labelled in albumin, but the peptides with highest specific activity after short incubation times corresponded to those with highest specific activities after long incubation times. 5. Leucine released from the C-terminus of albumin had a higher specific activity than the mean specific activity of the remaining leucine residues in albumin. 6. The peptide with the highest specific activity in albumin is probably derived from the C-terminus of the protein. 7. [(14)C]Glutamic acid is incorporated into the N-terminus of albumin after incubating the microsome fraction with this isotopically labelled amino acid, cell sap and a source of energy. The specific activity of the N-terminal glutamic acid under these conditions is less than the mean specific activity of the remaining glutamic acid and glutamine residues in albumin. 8. The results are interpreted as reflecting a sequential synthesis of serum albumin in the isolated microsome fraction of rat liver. The direction of synthesis of albumin is from the N-terminus towards the C-terminus. 9. The bulk of incorporation of radioactive amino acid into albumin in the isolated microsome fraction is due to completion of partially completed, pre-existing peptide and polypeptide chains. A limited synthesis of new chains of albumin does, however, occur.

Amino Acids↗

PubMed1976

Schwann cell multiplication after crush injury of unmyelinated fibers.

The intensity and duration of Schwann cell multiplication in unmyelinated fibers after crush injury of cervical sympathetic trunks (CSTs) in adult mice was studied using radioautography and electron microscopy. At the level of crush, labeling indexes rose to 22.5% on the second day after injury, but distal to this level, labeling reached a peak of only 2.5%. By the ninth day labeling declined to 1% or less at both sites. Electron microscopy confirmed that the increase in nuclei at the crush was mainly an increase in Schwann cells. Thus, the intensity of Schwann cell multiplication differed between crush and distal sites along the same unmyelinated nerve. The Schwann cell proliferation in the distal CSTs was less intense than that reported in previous studies on myelinated nerves.

Animals↗

PubMed1977

Axoplasmic transport in ocular hypotony and papilledema in the monkey.

Orthograde and retrograde axoplasmic transport were studied in optic nerve heads of seven hypotensive Macaca fascicularis eyes. Orthograde transport was studied by radioautography after intravitreal radioisotope injections. Retrograde transport was studied in the same eyes by horseradish peroxidase injection into the dorsal lateral geniculate nuclei or optic tracts. Three eyes had developed marked papilledema before injections. Orthograde axoplasmic transport was blocked in swollen axons of the optic disc anterior to Bruch membrane and in the lamina scleralis. Retrograde transport was blocked in axons within the lamina scleralis along the posterior edges of transverse scleral beams and in axons in the choroidal portion of the nerve head posterior to Bruch membrane. These results support the general concept that axoplasmic transport in the optic nerve head is sensitive to alterations in intraocular pressure, either increases or decreases. The edges of Bruch membrane and the openings in the lamina scleralis may constrict axon bundles in ocular hypotony.

Animals↗

PubMed1981

Pressure-induced optic nerve axonal transport interruption in cat eyes.

After intravitreal injection of tritiated leucine, optic nerve axonal transport was studied in 30 cat eyes by tissue radioautography. Twenty-five experimental eyes were examined after four hours of acute pressure elevation with perfusion pressures maintained at 20 to 70 mm Hg. In five control specimens, intraocular pressures were maintained at 10 mm Hg for the four-hour interval. The extent of leucine accumulation, as seen by radioautographs, was inversely proportional to the perfusion pressure. Accumulation was limited to the region fo the lamina cribrosa. The anatomic distribution and pressure response of this transport interruption were similar to those seen in primate eyes studied under similar conditions.

Animals↗