scholarly journals In vitro autoradiographic visualization of occupied estrogen receptors in the rat brain with an iodinated estrogen ligand.

1993 ◽  
Vol 41 (9) ◽  
pp. 1279-1290 ◽  
Author(s):  
M J Walters ◽  
T J Brown ◽  
R B Hochberg ◽  
N J MacLusky
Keyword(s):  
Estrogen Receptors ◽  
Computer Assisted ◽  
Physiological Changes ◽  
Tissue Sections ◽  
Receptor Complexes ◽  
Saturation Binding ◽  
Cell Groups ◽  
Cryostat Sections

Methods have been developed for the selective measurement of occupied estrogen receptors (ER) in brain tissue sections. Cryostat sections of unfixed tissue were incubated with radiolabeled estrogen at physiological temperatures, displacing endogenous receptor-bound estrogen by radioligand and thereby allowing the receptor complexes to be visualized autoradiographically after washing to remove nonspecifically bound steroid. The resultant autoradiographs were analyzed by computer-assisted densitometry. Synthetic 11 beta-methoxy-substituted radiolabeled estrogens gave the best autoradiographic images, as a result of reduced nonspecific labeling, although [3H]-estradiol was also used successfully. With the synthetic ER ligand 11 beta-methoxy 16 alpha-[125I]-iodo-estradiol, exposure times of less than 24 hr generated acceptable autoradiographs; with 3H-labeled estrogens, exposures of 3 months or more may be required. The method is sufficiently sensitive to detect physiological changes in ER occupation and to allow determination of receptor affinities and saturation binding capacities in discrete cell groups identified in sections from individual animals.

scholarly journals Microspectrophotometric quantitation of the diaminobenzidine reaction for histochemical demonstration of cytochrome oxidase activity.

1978 ◽  
Vol 26 (3) ◽  
pp. 157-162 ◽  
Author(s):  
A C Frasch ◽  
M E Itoiz ◽  
R L Cabrini
Keyword(s):  
Cytochrome Oxidase ◽  
Incubation Medium ◽  
Histochemical Demonstration ◽  
Tongue Muscle ◽  
Tissue Sections ◽  
Direct Light ◽  
Fixed Concentration ◽  
Set Up ◽  
Cryostat Sections

Polyacrylamide models in which an extract of cattle heart mitochondria was incorporated, as well as cryostat sections of tongue muscle and epithelium, were used to set up the conditions under which the histochemical reaction for the demonstration of cytochrome oxidase can be quantitated. Using diaminobenzidine in a concentration of 5.5 mM, cytochrome C in a fixed concentration of 76 micron and keeping the incubation medium away from direct light action, enzyme activity can be evaluated by means of direct microphotometry on tissue sections. Each biologic model requires previous individual determination of the measurement limits. These limits can be readily established by using a small chamber for the incubation medium, which can be placed in the microphotometer, allowing the reaction rate to be following using a single section.

scholarly journals The binding of 3H-labelled oestradiol- and progesterone-receptor complexes to hypothalamic chromatin of male and female sheep

1978 ◽  
Vol 176 (3) ◽  
pp. 873-883 ◽  
Author(s):  
B N Perry ◽  
A Lopez
Keyword(s):  
Progesterone Receptor ◽  
Receptor Binding ◽  
Guanidine Hydrochloride ◽  
Male And Female ◽  
Receptor Complexes ◽  
Related Difference ◽  
Saturation Binding ◽  
Acidic Proteins ◽  
Female Sheep

Chromatin isolated from hypothalamic nuclei of sexually mature entire male and female sheep was linked to cellulose in u.v. light. The saturation binding of 3H-labelled oestrogen- and progesterone-receptor complexes, prepared by (NH4)2SO4 precipitation from the 105000g supernatant of hypothalamic cytosol, was then measured in vitro in 0.15m-KCl. Saturation binding was also measured after extraction of histones and masking acidic proteins. Salt + urea was observed to be more effective than guanidine hydrochloride in unmasking receptor acceptor sites, and the binding of labelled receptor complexes to dehistonized unmasked chromatin was shown to be largely resistant to 0.4m-KCl extraction. Whereas extents of receptor-complex binding were similar to published values for comparable preparations of hen oviduct chromatin, no sex-related difference was observed. However, binding of progesterone-receptor to chromatin was greater than that of oestradiol-receptor. Binding also increased more after removal of histones and masking acidic proteins, suggesting the presence of a greater number of progesterone-receptor acceptor sites in hypothalamic chromatin than of estradiol-receptor acceptor sites. The failure to demonstrate a sex-related difference in oestradiol-receptor binding to hypothalamic chromatin in vitro is discussed.

Radiochemical determination of estrogen receptors in cryostat sections of target tissues

1984 ◽  
Vol 21 (2) ◽  
pp. 127-134 ◽  
Author(s):  
A.F.P.M. De Goeij ◽  
M.P.W. Volleberg ◽  
G.G. Hondius ◽  
F.T. Bosman
Keyword(s):  
Estrogen Receptors ◽  
Radiochemical Determination ◽  
Cryostat Sections

Computer-Assisted High-Re Solution TEM

1990 ◽  
Vol 48 (1) ◽  
pp. 162-163
Author(s):  
F.A. Ponce ◽  
H. Hikashi
Keyword(s):  
Signal To Noise Ratio ◽  
Accurate Determination ◽  
Computer Software ◽  
Video Camera ◽  
Image Contrast ◽  
Objective Lens ◽  
Computer Assisted ◽  
Optical Parameters ◽  
Astigmatism Correction

The determination of the atomic positions from HRTEM micrographs is only possible if the optical parameters are known to a certain accuracy, and reliable through-focus series are available to match the experimental images with calculated images of possible atomic models. The main limitation in interpreting images at the atomic level is the knowledge of the optical parameters such as beam alignment, astigmatism correction and defocus value. Under ordinary conditions, the uncertainty in these values is sufficiently large to prevent the accurate determination of the atomic positions. Therefore, in order to achieve the resolution power of the microscope (under 0.2nm) it is necessary to take extraordinary measures. The use of on line computers has been proposed [e.g.: 2-5] and used with certain amount of success.We have built a system that can perform operations in the range of one frame stored and analyzed per second. A schematic diagram of the system is shown in figure 1. A JEOL 4000EX microscope equipped with an external computer interface is directly linked to a SUN-3 computer. All electrical parameters in the microscope can be changed via this interface by the use of a set of commands. The image is received from a video camera. A commercial image processor improves the signal-to-noise ratio by recursively averaging with a time constant, usually set at 0.25 sec. The computer software is based on a multi-window system and is entirely mouse-driven. All operations can be performed by clicking the mouse on the appropiate windows and buttons. This capability leads to extreme friendliness, ease of operation, and high operator speeds. Image analysis can be done in various ways. Here, we have measured the image contrast and used it to optimize certain parameters. The system is designed to have instant access to: (a) x- and y- alignment coils, (b) x- and y- astigmatism correction coils, and (c) objective lens current. The algorithm is shown in figure 2. Figure 3 shows an example taken from a thin CdTe crystal. The image contrast is displayed for changing objective lens current (defocus value). The display is calibrated in angstroms. Images are stored on the disk and are accessible by clicking the data points in the graph. Some of the frame-store images are displayed in Fig. 4.

Determination of in vitro „anti-aging„-effects of Ganoderma pfeifferi

Planta Medica ◽  
2010 ◽  
Vol 76 (12) ◽  
Author(s):  
W Jülich ◽  
J Pörksen ◽  
H Welzel ◽  
U Lindequist
Keyword(s):  
Aging Effects

In vitro determination of the skin anti-aging potential of eleven South African plants

Planta Medica ◽  
2013 ◽  
Vol 79 (13) ◽  
Author(s):  
GN Ndlovu ◽  
G Fouche ◽  
W Cordier ◽  
V Steenkamp ◽  
M Tselanyane
Keyword(s):  
South African ◽  
South African Plants ◽  
African Plants

A Molecular Approach to Immunoscintigraphy: A Study of the T-Antigen Conformation on the Surface of Tumors

1987 ◽  
Vol 26 (01) ◽  
pp. 1-6 ◽  
Author(s):  
S. Selvaraj ◽  
M. R. Suresh ◽  
G. McLean ◽  
D. Willans ◽  
C. Turner ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Tumor Cell ◽  
T Antigen ◽  
Human Carcinomas ◽  
Animal Tumor ◽  
Synthetic Antigens

The role of glycoconjugates in tumor cell differentiation has been well documented. We have examined the expression of the two anomers of the Thomsen-Friedenreich antigen on the surface of human, canine and murine tumor cell membranes both in vitro and in vivo. This has been accomplished through the synthesis of the disaccharide terminal residues in both a and ß configuration. Both entities were used to generate murine monoclonal antibodies which recognized the carbohydrate determinants. The determination of fine specificities of these antibodies was effected by means of cellular uptake, immunohistopathology and immunoscintigraphy. Examination of pathological specimens of human and canine tumor tissue indicated that the expressed antigen was in the β configuration. More than 89% of all human carcinomas tested expressed the antigen in the above anomeric form. The combination of synthetic antigens and monoclonal antibodies raised specifically against them provide us with invaluable tools for the study of tumor marker expression in humans and their respective animal tumor models.

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