Autoradiography features

The adult brain is endowed with nuclear as well as cytosolic and membrane T3 receptors that have been visualized by autoradiography and studied biochemically [30-33]. Both neurons and neuropil are labeled by [ 1251]T3, and the labeling is selective across brain regions. Functionally, one of the most prominent features of neural action of thyroid hormone in adulthood is subsensitivity to norepinephrine as a result of a hypothyroid state [27], These changes may be reflections of loss of dendritic spines in at least some neurons of the adultbrain. Clinically, thyroid hormone deficiency increases the probability of depressive illness, whereas thyroid excess increases the probability of mania (Ch. 52) in susceptible individuals [27],... 

Cellular autoradiography techniques using radioactive nucleic acid probes have several features in common with nucleic acid immunocytochemistry. The method is based on the hybridization of radioactive probes to cellular targets and the subsequent exposure of photographic emulsion, which, when developed, reveals blackened (exposed) silver grains close to the site of hybridiza-hon. Hence, cellular autoradiography techniques permit excellent specihcity and localizahon of the hybridized probe—to 1 qm when tritium is the label used in the autoradiography-based method (9). 

Cellular autoradiography techniques using radioactive nucleic acid probes have several features in common with nucleic acid immunocytochemistry. The method is based on the hybridization of radioactive... 

Some relevant terms for activation analysis are activation analysis, neutron activation analysis (NAA), instrumental neutron activation analysis (INAA), neutron activation analysis with radiochemical separation (RNAA), photon activation, neutron capture prompt gamma activation analysis (PGAA), charged particle activation, autoradiography, liquid scintillation counting, nuclear microprobe analysis, radiocarbon (and other element) dating, radioimmunoassay, nuclear track technique, other nuclear and radiochemical methods. Briefly, the salient features of some of the more popular techniques are as follows ... 

Figure 22.8 Amniote limb development. A representative amniote (Hamburger/Hamilton stage 25/6 and 26/7 chick leg bud) whose limb prechondrogenic pattern is revealed by 3SS04 autoradiography it demonstrates common tetrapod features (Figure 22.6) such as postaxial branching with 4 as the first digit, and the digital arch (da) (P=posterior, stages 25/6 and 26/7, Hinchliffe, 1977, bar=0.5 mm).

The distribution of activation can be determined by the technique of autoradiography, where a photographic film is placed over the surface of the activated specimen (Fig. 2b). It is interesting to note that the resolution which may be needed for studying the details of sintering cannot be achieved by using most radioactive tracers in the usual way because cross-fire subsurface activity would then obscure features of the distribution at the surface. 

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