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Biomedical subjects

G Orlandini

Publications and source records attributed to G Orlandini.

At least 55 records · Page 3Linked to original sources
PubMed1993

Acute and chronic hyperbaric oxygen exposure in humans: effects on blood polyamines, adrenocorticotropin and beta-endorphin.

Plasma beta-endorphin, adrenocorticotropin (ACTH) and blood polyamine (spermidine and spermine) concentrations were evaluated in healthy adult male athletes undergoing hyperbaric oxygen exposure for 10 days (2.8 atm, 100% O2, 60 min daily). In the "acute phase", corresponding to the first day of treatment, and in the "acute in the chronic phase", corresponding to the values obtained on the 5th and 10th days after 60 min of hyperbaric O2, both ACTH and beta-endorphin levels increased significantly, whereas no variations were observed for polyamine concentrations. In the "chronic phase", corresponding to the basal values of the 5th and 10th days of treatment, we found a different pattern. In fact, the concentration of polyamines showed a remarkable enhancement, while ACTH and beta-endorphin levels remained unchanged. No significant variations were observed during hyperbarism with air. These results demonstrate different modifications of polyamines and beta-endorphin and ACTH in subjects submitted to hyperbaric oxygen exposure.

Adrenocorticotropic Hormone↗
PubMed1991

Different epithelia in the distal human male urethra.

The distal segment of the human male urethra, in particular the fossa navicularis, was studied with light- and electron microscopy as well as by means of histochemical and immunocytochemical methods. The fossa navicularis of the urethra contains a circumscribed zone of extremely thick, non-keratinized stratified squamous epithelium composed of cells containing a large amount of glycogen. These cells lack acid phosphatase activity and lysozyme-like immunoreactivity, both of which can be demonstrated to varying extents in the other zones of the distal male urethra. These glycogenrich cells are considered to be the substrate for an endogenous flora of lactobacteria, whereas the acid-phosphatase activity and the lysozyme-like immunoreactivity indicate the presence of macrophages and the secretion of bactericidal agents at the epithelial surface. These observations suggest that the different zones with heterogeneous properties in the distal male urethra probably represent a defense system against the invasion of pathogenic microorganisms. Moreover, the glycogen-rich zone, which resembles the glycogen-rich epithelium of the vagina, is estrogen-dependent. This is demonstrated in cases of sex reversal in which after long-lasting estrogen treatment the glycogen-rich zone becomes extremely extended by displacement of the neighbouring epithelium.

Adolescent↗
PubMed1990

[Seasonal changes in seminiferous tubules and Leydig cells of hibernating bats].

We studied the seasonal course of Leydig cells combined with spermatogenesis and blood testosterone concentrations. The reproductive cycle of Pipistrellus kuhli kuhli and Eptesicus serotinus is characterized by seminiferous tubules which reactivate after a period of complete quiescence extending for the whole winter hibernating sleep and spring (March-June) periods. During hibernation, Leydig cells show ultrastructural features which stress a low secretory activity with corresponding low concentration of blood testosterone. With the beginning of summer, Leydig cells increase their metabolic activity reaching a top in the mating season (fall) when also blood testosterone and spermatogenesis reach the highest levels. The authors, after some comparative morphological considerations with different hibernating animals, assert that the reproductive processes of these two bats are not strictly species-linked, but rather dependent, besides seasonal thermal changes, upon habitat and feeding sources.

Animals↗
PubMed1990

The migration of lymphocytes and polymorphonuclear leukocytes across the endothelial wall of the absorbing peripheral lymphatic vessel.

We studied the process of transendothelial migration of lymphocytes and polymorphonuclear leukocytes in the absorbing peripheral lymphatic vessels of small intestine and urinary bladder, under normal conditions, lymphatic stasis and prolonged fast. By ultrathin serial sections and three-dimensional models we found that lymphocytes and leukocytes share a common migration pathway from the interstitium into the lumen of the lymphatic vessel, namely 'the intraendothelial channel'. The migratory process of these cells occurs in several steps: approach to the endothelial wall, entry and run along the channel and finally coming out into lymphatic lumen. Our findings are compared with those concerning lymphatics in pathological conditions and blood vessels. Further considerations concern the possible mechanisms underlying this kind of transendothelial migration.

Animals↗
PubMed1990

Macrophage migration through the endothelium in the absorbing peripheral lymphatic vessel of the small intestine.

TEM and three-dimensional models of the absorbing peripheral lymphatic vessel (ALPA) of the small intestine demonstrate that macrophages migrate from the interstitium into the lumen through the endothelial cell (transcellular pathway). Macrophages cross through a 'migration pore' which arises by an 'erosive process' in the cytoplasmic expansion of the endothelial cell. The pore is completely independent of the intercellular junction which is always sealed by junctional complexes. Furthermore several sites of contact between macrophage and endothelial cell membranes stress a possible functional role played by cellular interactions. Transcellular migration processes under normal conditions are compared with pathological or experimental ones.

Animals↗
PubMed1989

Fine structure of the excretory system of the deep posterior (Ebner's) salivary glands of the human tongue.

Human deep posterior lingual glands (von Ebner's glands) are located beneath the circumvallate papillae. They are formed by tubuloalveolar adenomeres, intercalated ducts and excretory ducts coming together in the main excretory duct. The tubuloalveolar cells, pyramid-shaped, show large and dense secretory granules (clear cored) throughout the cytoplasm, rare basal folds and packed cisternae of rough endoplasmic reticulum (RER) at the basal pole. The columnar cells of the intercalated ducts are arranged in a monolayer. They are characterized by dense, clear-core secretory granules (mostly in the apical cytoplasm), a basal nucleus, well-developed RER and Golgi apparatus, and thin filaments distributed in supra- and perinuclear cytoplasm. Striated ducts are absent. Excretory ducts, coming together in the main duct, are lined by a bistratified epithelium. The inner layer consists of columnar cells showing bundles of tonofilaments with scarce secretory activity. The outer layer is composed of basal cells lying on the basal lamina. The main excretory duct, which opens at the bottom of the vallum, shows a stratified epithelium. The outer side is composed of 2-3 layers of malpighian cells lying on the basal lamina. The inner side consists of a single layer of cuboidal-columnar cells with dense apical granules and well-developed organelles synthesizing and condensing secretions. These cells interpolate with goblet cells, rare mitochondria-rich cells, ciliated cells and numerous small globous cells showing a clear matrix and lacking secretory granules. The cilia show a 9 + 2 microtubular structure with basal bodies provided with striated rootlets. Myoepithelial cells surround with their processes the basal portions of the secretory cells and the intercalated ducts. The conclusions concern some comparative aspects and some hypothesis on the functional role of goblet cells, ciliated cells and epithelial cells lining the different ducts, also in relation to the final secretory product.

Aged↗