Etomidate and Cushing's syndrome.
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Anesthesia, Intravenous↗
Biomedical subjects
D Pignatelli
Publications and source records attributed to D Pignatelli.
Synaptic architecture of glomeruli in superficial dorsal horn of rat spinal cord, as shown in serial reconstructions.
Using serial section EM analysis, synaptic organization of glomeruli in lamina II of the dorsal horn of the rat has been examined. Four C1-terminals (small, dark and sinuous), four CIIa (large, light and regular, without neurofilaments) and four CIIb (with neurofilaments) at the centres of synaptic glomeruli of types I, IIa and IIb, respectively, were serially sectioned and reconstructed. Asymmetrical synapses between the central terminal (C) and dendritic profiles without synaptic vesicles (D) prevailed in all types of glomeruli. Symmetrical dendroaxonic contacts with presynaptic dendrites (V1----C) occurred practically only in type I glomeruli in which there were also more asymmetrical C----V1 contacts than in type II glomeruli. Symmetrical axoaxonic synapses V2----C were more abundant in type IIa and IIb glomeruli. Type IIa glomeruli had a significantly larger number of C----D synapses and of all synapses per unit area of C surface, than type IIb glomeruli. Triadic systems with C and D postsynaptic to V2 were nearly as numerous as those involving V1 in type I glomeruli. Triads with V2 were however largely preponderant in type IIa and virtually exclusive in type IIb. It thus seems that each of the three types of glomerulus has its own pattern of synaptic interactions which might reflect specific complexes of feed-forward and feed-back mechanisms. In type I glomeruli, excitation of second-order neurons by nociceptive C1 terminals may be controlled in similar proportions by presynaptic dendrites excited within the glomerulus by the C terminal itself, or by peripheral axons excited from outside the glomerulus. This kind of control is likely to prevail in type IIa glomeruli and to be the only efficient modulatory mechanism in type IIb glomeruli.
Animals↗
Effects of dorsal rhizotomy on the several types of primary afferent terminals in laminae I-III of the rat spinal cord. An electron microscope study.
After cervical dorsal rhizotomy, small dark central terminals (C1) of glomeruli underwent electron dense changes at 8 h and were all degenerated at 36 h; their number persisted, though slightly diminished, up to 15 days, glial engulfment being negligible. Light large central terminals without neurofilaments (CIIa) showed electron-lucent or electron-dense degeneration from 14 to 36 h, while those with neurofilaments (CIIb) exhibited increased neurofilamentous areas, with depletion and presynaptic concentration of synaptic vesicles as in the electron-lucent change, at the 8-36 h postrhizotomy periods. Both CII-varieties were all degenerated at 36 h and became electron dense at 48 h; glial phagocytosis was intense and no terminals were present after 4 days. It is concluded that in the rat the 3 types of central glomerular terminals are primary axons, and that each type undergoes a different pattern of degeneration which points to a separate primary afferent origin. Numerous nonglomerular axodendritic endings began showing electron-dense degeneration at 8 h which rapidly masked their normal structure, although most appeared to contain round agranular vesicles, and some of them dense-cored vesicles (in lamina I). A few endings exhibited electron-lucent degeneration. Labeling methods seem preferable for studying the primary origin of nonglomerular terminals, due to the difficulty in recognizing the normal predegenerative structure of these profiles.
Animals↗
Direct effects of stress on adrenocortical function.
The adrenal gland plays a pivotal role in the stress response since this response involves the hypothalamic-pituitary-adrenal axis (HPAA) and the sympatho-adrenomedullary system (SAMS) as its two principal components. An important relation between the immune system and the other stress response systems is also centered on the adrenal gland. It is well known that the cortex secretes glucocorticoids while the medulla secretes epinephrine, two of the major effects of the stress response. Some other aspects, however, also deserve special consideration: The paracrine effects of the cortical secretion on the medullary cells through the special irrigation system of the gland and reciprocally the influence of the medulla upon the cortex, either by direct close contact or by local innervation. The influence of vascular events also needs to be considered as well as the existence of some local hormonal axis such as those resulting from the local production of renin or CRH in adrenal cells. Some other cells such as mast cells, macrophages and endothelial cells seem to play a role in the regulation of the adrenal cortex and hence in the tuning of the stress response. Stressors stimulate the release of CRH from the hypothalamic paraventricular nucleus inducing the secretion of ACTH from the pituitary and that of corticosteroids from the adrenal cortex. Through the activation of the sympathetic system the adrenal can be stimulated even before adequate levels of ACTH are reached. In conditions of chronic stress the adrenal cortex undergoes an adaptation that allows the hypersecretion of glucocorticoids to occur even without the increment of ACTH.
Adrenal Cortex↗
The development of the adrenal cortex in the rat. An immunohistochemical study.
The Inner Zone Antibody (IZAb) is a monoclonal antibody which interacts with an antigen found predominantly in rat adrenal inner cortical zones. Since its expression increases after ACTH treatment the antigen may have a role in steroidogenesis although, so far, this has not yet been fully characterised. Due to its molecular weight, it cannot be any of the known cytochrome P450 proteins. In this study we examined the expression of IZAb in male and female rats throughout their postnatal development and in aged animals. In a different set of animals, blood was collected for hormonal assays and the adrenals stained with classical methods. The staining with IZAb was clear from the first post-natal day. The zona glomerulosa which was always present at birth, was easily distinguished and unstained. The staining in the inner zone cells was fainter at birth and increased progressively until postnatal day 20. Afterwards these cells were remarkably stained at all ages. Medullary cells were also present from birth although they were generally found in clusters instead of constituting a well defined zone. Cortical cells appeared in the medullary zone at all ages after its complete development. The zona glomerulosa increased in size until approximately postnatal day 40 while the inner zones increased until day 70. The area of the cortex was significantly different between the two sexes from day 50 onwards and this was predominantly due to differences in the zona fasciculata. Corticosterone levels increased until approximately day 25 in the male rat and until day 45 in the female.(ABSTRACT TRUNCATED AT 250 WORDS)
Adrenal Cortex↗
Ontogeny of 3beta-hydroxysteroid dehydrogenase expression in the rat adrenal gland as studied by immunohistochemistry.
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3-Hydroxysteroid Dehydrogenases↗
DNA quantification and ploidy patterns in human adrenocortical neoplasms.
The determination of DNA ploidy and the study of the cell cycle in adrenocortical tumoral cells could help in the distinction between benign and malignant lesions and also in the prediction of the biological behaviour of these tumors. We analysed 32 cases of adrenal tissue (8 normal adrenals--N, 12 benign adenomas--A and 12 carcinomas--C). DNA was quantified by image analysis of Feulgen stained sections (Ahrens System) employing ACAS3 software. The DNA content was considered to be diploid in 70% of the N and in 67% of the A groups and in none of C. In this latter group nearly 90% were triploid or tetraploid while this did not occur in any of the A cases. The percentage of cases with a 5c-exceeding rate (5cER) above 5% was nil in the N and A groups and 100% in C. In what concerns the distribution in the cell cycle we found a very distinctive pattern between the groups as the percentage of cases in which the S-phase fraction exceeded 33% was nil in the normals, 8% in A and 83% in the C cases. In conclusion, there was a good correlation between the analysed parameters and the clinically defined groups of adrenal cortex tumors.
Adenoma↗