scholarly journals Autoradiographic detection of [125I]-secondary antiserum: a sensitive light and electron microscopic labeling method compatible with peroxidase immunocytochemistry for dual localization of neuronal antigens.

1986 ◽  
Vol 34 (6) ◽  
pp. 707-718 ◽  
Author(s):  
V M Pickel ◽  
J Chan ◽  
T A Milner

We examined whether autoradiographic localization of [125I]-antirabbit immunoglobulin (IgG) was suitable for light and electron microscopic detection of a rabbit antiserum to the catecholamine-synthesizing enzyme, tyrosine hydroxylase (TH), and whether autoradiographic and peroxidase labeling could be combined for simultaneous immunocytochemical identification of TH and neuropeptides in brain. Adult rat brains were fixed by aortic arch perfusion with acrolein and paraformaldehyde. Vibratome sections of the fixed tissues were incubated with various dilutions of TH antiserum followed by [125I]-secondary IgG. These sections were then directly processed for autoradiography or were incubated with rabbit antiserum to substance P (SP) or methionine [Met5]-enkephalin (ME). These latter sections were then processed by the peroxidase-antiperoxidase (PAP) or conjugated peroxidase methods followed by autoradiography. Exposure periods of 12-20 days for light microscopy or 90 days for electron microscopy yielded substantial accumulations of silver grains even at the highest (1:30,000) dilution of TH antiserum. At this dilution, immunoreactivity for TH was virtually nondetectable by PAP and conjugated peroxidase methods. The differential sensitivities of the autoradiographic versus peroxidase methods provided a means for separable identification of rabbit antiserum to TH and to SP or ME. Ultrastructural analysis of the catecholaminergic neurons in the medial nuclei of the solitary tract (NTS) showed selective cytoplasmic localization of silver grains for [125I]-labeling of TH in perikarya, dendrites, and terminals. Within single thin sections prepared for dual labeling, the peroxidase marker for SP and for ME was differentially localized with respect to autoradiographic labeling of TH.

Author(s):  
A. Haddad ◽  
J-J. Lachat ◽  
R. P. Gonçalves

Biosynthesis, migration and renewal of glycoproteins were studied by radioautography in the renal glomeruli after administering L-3H-fucose to rats which were killed at several time intervals after injection, by perfusion of glutaraldehyde through the abdominal aorta. Small pieces of the kidney were post fixed in 0s04, dehydrated and embedded in Epon 812. Semithin and thin sections of the renal cortex were processed for light and electron microscopic radioautography, respectively. At the light microscope level (Fig. 1) it was observed that the main site of incorporation of 3H-fucose into glycoproteins was the paranuclear region of the visceral epithelial cells (podocytes). Weak paranuclear radioautographic reactions were also observed in endothelial and mesangial cells at 10 minutes after injection. At the longer time intervals these paranuclear reactions disappeared and the silver grains were mostly overlying the several components of the capillary wall. Silver grain counts showed that the peak of the silver grain density over the glomeruli occurred at 4 hours after injection; by 14 days the radioautographic reactions were almost negligible.


1973 ◽  
Vol 57 (1) ◽  
pp. 77-87 ◽  
Author(s):  
M. M. Magalhães ◽  
Antonio Coimbra

Rabbit retinas were incubated in medium containing 500 µCi of [3H]leucine for 3 min, and transferred to medium without isotope for another 7, 17, 37, 57, and 117 min. Retinal pieces were fixed in paraformaldehyde and osmium tetroxide and embedded in Epon. Thin sections were autoradiographed with Ilford L4 emulsion, and a quantitative study of silver grain distribution per Müller cell portion, and per Müller cell organelle, was carried out. Grain density per unit area was high over the middle cell portion at each incubation interval. Silver grains were numerous over background cytoplasm (which comprised free ribosomes) but their percentage was constant at all times and their relative concentration low. Silver grains were numerous and highly concentrated, at pulse incubation, over the rough endoplasmic reticulum (RER) and then decreased sharply, but this decline coincided with an increase over the Golgi complex, peaking at 20 min. Another peak appeared over the cell periphery at 60 min. These findings suggest the simultaneous synthesis of two types of proteins in Müller cells; structural proteins in background cytoplasm and proteins of secretory type in the RER.


Author(s):  
J. T. Stasny ◽  
R. C. Burns ◽  
R. W. F. Hardy

Structure-functlon studies of biological N2-fixation have correlated the presence of the enzyme nitrogenase with increased numbers of intracytoplasmic membranes in Azotobacter. However no direct evidence has been provided for the internal cellular localization of any nitrogenase. Recent advances concerned with the crystallizatiorTand the electron microscopic characterization of the Mo-Fe protein component of Azotobacter nitrogenase, prompted the use of this purified protein to obtain antibodies (Ab) to be conjugated to electron dense markers for the intracellular localization of the protein by electron microscopy. The present study describes the use of ferritin conjugated to goat antitMo-Fe protein immunoglobulin (IgG) and the observations following its topical application to thin sections of N2-grown Azotobacter.


Author(s):  
Glen B. Haydon

High resolution electron microscopic study of negatively stained macromolecules and thin sections of tissue embedded in a variety of media are difficult to interpret because of the superimposed phase image granularity. Although all of the information concerning the biological structure of interest may be present in a defocused electron micrograph, the high contrast of large phase image granules produced by the substrate makes it impossible to distinguish the phase ‘points’ from discrete structures of the same dimensions. Theory predicts the findings; however, it does not allow an appreciation of the actual appearance of the image under various conditions. Therefore, though perhaps trivial, training of the cheapest computer produced by mass labor has been undertaken in order to learn to appreciate the factors which affect the appearance of the background in high resolution electron micrographs.


Author(s):  
Dr. G. Kaemof

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.


Author(s):  
J. E. Michaels ◽  
J. T. Hung ◽  
E. L. Cardell ◽  
R. R. Cardell

In order to study early events of glycogen synthesis, we have used adrenalectomized (ADX) rats fasted overnight and injected with the synthetic glucocorticoid dexamethasone (DEX) to stimulate glycogen synthesis. Rats were given DEX 0-5 hr prior to sacrifice and injected with 2 mCi 3H-galactose 1 hr prior to sacrifice. Liver was prepared for light (LM) and electron microscopic (EM) radioautography by routine procedures.The concentration of silver grains over hepatic cytoplasm was measured in LM radioautographs using a Zeiss Videoplan. The hepatocytes were categorized as unlabeled if no silver grains (gr) were present, lightly labeled (<10gr/100 μm2 cytoplasm) or intensely labeled (>10 gr/1002 μm cytoplasm). Although very few hepatocytes showed heavy labeling after 1 hr treatment with DEX, by 2 hr after DEX treatment 8% of the cells distributed throughout the lobule were intensely labeled.


Author(s):  
P.W. Coates ◽  
E.A. Ashby ◽  
L. Krulich ◽  
A. Dhariwal ◽  
S. McCann

The morphologic effects on somatotrophs of crude sheep hypothalamic extract prepared from stalk-median eminence were studied by electron microscopy in conjunction with concurrently run bioassays performed on the same tissue samples taken from young adult male Sherman rats.Groups were divided into uninjected controls and injected experimentals sacrificed at 5', 15', and 30' after injection. Half of each anterior pituitary was prepared for electron microscopic investigation, the other half for bioassay. Fixation using collidine buffered osmium tetroxide was followed by dehydration and embedment in Maraglas. Uranyl acetate and lead citrate were used as stains. Thin sections were examined in a Philips EM 200.Somatotrophs from uninjected controls appeared as described in the literature (Fig. 1). In addition to other components, these cells contained moderate numbers of spherical, electron-dense, membrane-bound granules approximately 350 millicrons in diameter.


Author(s):  
D.R. Mattie ◽  
C.J. Hixson

Dimethylmethylphosphonate (DMMP) is a simple organophosphate used industrially as a flame retardant and to lower viscosity in polyester and epoxy resins. The military considered the use of DMMP as a nerve gas simulant. Since military use of DMMP involved exposure by inhalation, there was a need for a subchronic inhalation exposure to DMMP to fully investigate its toxic potential.Male Fischer-344 rats were exposed to 25 ppm or 250 ppm DMMP vapor on a continuous basis for 90 days. An equal number of control rats were sham-exposed. Following the 90-day continuous exposure period, 15 male rats were sacrificed from each group. Two rats from each group had the left kidney perfused for electron microscopic examination. The kidneys were perfused from a height of 150 cm water with 1% glutaraldehyde in Sorensen's 0.1M phosphate buffer pH 7.2. An additional kidney was taken from a rat in each group and fixed by immersion in 2.5% glutaraldehyde and 2% paraformaldehyde in 0.1M cacodylate buffer pH 7.4. A portion of the 9 kidneys collected for electron microscopy were processed into Epon 812. Thin sections, stained with uranyl acetate and lead citrate, were examined with a JEOL 100B Transmission Electron Microscope. Microvilli height was measured on photographs of the cells of proximal tubules. This data, along with morphologic features of the cells, allows the proximal convoluted tubules (PCT) to be identified as being S1, S2, or S3 segment PCT.


Author(s):  
A.S. Lossinsky ◽  
M.J. Song

Previous studies have suggested the usefulness of high-voltage electron microscopy (HVEM) for investigating blood-bram barrier (BBB) injury and the mechanism of inflammatory-cell (IC) attachment. These studies indicated that, in evaluating standard conventional thin sections, one might miss cellular attachment sites of ICs in their process of attaching to the luminal endothelial cell (EC) surface of cerebral blood vessels. Our current studies in animals subjected to autoimmune disease suggest that HVEM may be useful in localizing precise receptor sites involved in early IC attachment.Experimental autoimmune encephalomyelitis (EAE) was induced in mice and rats according to standard procedures. Tissue samples from cerebellum, thalamus or spinal cords were embedded in plastic following vascular perfusion with buffered aldehyde. Thick (0.5-0.7 μm) sections were cut on glass knives and collected on Formvar-coated slot grids stained with uranylacetate and lead citrate and examined with the AEI EM7 1.2 MV HVEM in Albany, NY at 1000 kV.


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