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Biomedical subjects

S Magari

Publications and source records attributed to S Magari.

At least 37 records · Page 2Linked to original sources
PubMed1989

Morphology of arachnoid granulations and villi in the region of the human sella turcica--light microscopy and three-dimensional image analysis.

The distribution and structure of the arachnoid granulations and villi in the region of the sella turcica in human adult brains were observed under light microscopy. In order to study the interrelationships between the arachnoid projections, hypophysis, cavernous sinus, and sella turcica, we performed a three-dimensional reconstruction and analysis of the region with the use of a digital image-processing method. Arachnoid projections penetrating the dura were villous when they were few in number, but more frequently granular when they were numerous. No relationship was observed between the type of projections and the age or the underlying disease of the subjects. Brains which showed no or few arachnoid granulations or villi had a small and deep hypophyseal fossa with a poorly-developed intercavernous sinus or venous plexus. Three-dimensional image analysis revealed that arachnoid granulations and villi form a maze in the dura or connective tissue between the venous plexuses.

Adult↗
PubMed1989

Prostaglandin I2 synthase in the lymphatic endothelium of rat liver as revealed by preembedding immunoelectron microscopy.

Localization of prostaglandin I2 synthase-like immunoreactivity (PGI2SI) in the lymphatic endothelium of rat liver was investigated by means of preembedding immunoelectron microscopy. Vesicular and multivesicular bodies with PGI2SI were closely apposed to Golgi complexes of the endothelial cells. Membrane-bounded PGI2SI structures including vesicular and dense bodies were also present beneath the endothelial plasmalemma on both luminal and abluminal sides. Other organelles within the endothelial cells did not exhibit PGI2SI. These findings are consistent with previous biochemical and physiological studies suggesting prostaglandin I2 is produced in the Golgi apparatus and released into luminal and abluminal spaces through membrane-bounded structures containing PGI2SI.

Animals↗
PubMed1989

An immunoelectron microscopic study of von Willebrand factor in the thoracic duct endothelium of rats.

The localization of Von Willebrand factor-like immunoreactivity (VWFI) in the thoracic duct endothelium was investigated by means of preembedding immunoelectron microscopy. In the endothelial cells, VWFI was observed within rod-shaped Weibel-Palade bodies (WPBs) with an occasional tadpole-like appearance. The WPBs occasionally appeared to be associated with Golgi complexes of the endothelial cells. Some cisternae of the rough endoplasmic reticulum located in the perikarya of the endothelial cells also exhibited VWFI. There was a small number of large VWFI vesicles in the periphery of the endothelial cells. These findings provide morphological evidence for the thoracic duct as a site of VWF synthesis and suggest further that VWF is produced in the rough endoplasmic reticulum and transported into the WPBs and large vesicles occasionally via the Golgi apparatus.

Animals↗
PubMed1988

Fine structures of nerve fibers with corticotropin-releasing factor-like immunoreactivity in the rat lateral septum.

The fine structures of nerve fibers with corticotropin-releasing factor (CRF)-like immunoreactivity in the rat lateral septum were investigated by means preembedding immunoelectron microscopy. A number of CRF axon terminals formed synapses with cell bodies of non-immunoreactive septal neurons. They occasionally had broad terminal bulges whose subregions showed little or no immunoreactivity for CRF. CRF axon terminals were also in synaptic contact with non-immunoreactive dendrites or dendritic spines. Some dendrites with CRF were postsynaptic to non-immunoreactive axon terminals.

Animals↗
PubMed1988

Ontogeny and afferent connections of corticotropin releasing factor-like immunoreactivity in the rat neocortex.

The first set of the present experiments was designed to investigate the postnatal development of corticotropin releasing factor-like immunoreactivity (CRFI) in the rat cerebral cortex by means of cobalt-enhanced immunohistochemistry. Results showed the occurrence of CRFI fibres before cells in the developing rat cerebral cortex with and without colchicine treatment, suggesting that some CRFI cells in subcortical regions may project to the cerebral cortex. In the second set of experiments, ipsilateral double-labelled cells which contained both retrogradely transported horseradish peroxidase (HRP) and CRFI were observed in the zona incerta, subincertal nucleus, lateral hypothalamic area, perifornical hypothalamic area, and in the dorsal hypothalamic area after unilateral HRP injections into the cerebral cortex. These findings indicate the existence of corticopetal CRFI-containing projections arising from the above areas.

Animals↗
PubMed1988

Corticotropin releasing factor-containing afferents to the lateral septum of the rat brain.

Corticotropin releasing factor (CRF)-containing afferents to the rat lateral septum (LS) have been determined by means of cobalt-enhanced immunohistochemistry, tracing of retrograde transport of horseradish peroxidase (HRP), and by lesioning experiments. When unilateral lesions included the rostral part of the hypothalamus, CRF-like immunoreactive (CRFI) ipsilateral fibers in the LS decreased in number. Lesions in other brain regions did not cause alterations in the septal CRFI fibers. These findings suggest that the septal CRFI fibers originate in the rostral part of the hypothalamus. Furthermore, combined HRP and immunohistochemical staining on the same sections demonstrated double-labeled cells in two discrete areas within the rostral hypothalamus: one was the perifornical hypothalamic area (PeF) at the level of the paraventricular hypothalamic nucleus, and the other was the most caudal part of the anterior hypothalamic nucleus (AHc). These findings show that a large proportion of the CRFI projections to the LS have their origins in the PeF and AHc.

Animals↗
PubMed1988

A reliable method combining horseradish peroxidase histochemistry with immuno-beta-galactosidase staining.

A sensitive combination of horseradish peroxidase (HRP) tracing and immunohistochemistry was used by Rye et al. [J Histochem Cytochem (1984) 32:1145] in a search for the origins of neurotransmitter- and neuromodulator-containing nerve fibers in brain. In this combination, peroxidase as a marker in immunohistochemistry was thought to yield a homogeneous brown immunoreaction product of diaminobenzidine, different from the black granular reaction product of retrogradely transported HRP, which is visualized by the tetramethylbenzidine (TMB) reaction and subsequent stabilization. A neuron that exhibits both kinds of reaction products in its cytoplasm in sections subjected to combination staining is referred to as a double-labeled cell. With a combined HRP and corticotropin-releasing factor (CRF) immunoperoxidase-antiperoxidase (PAP) method, the first set of experiments showed "false" double-labeled cells in the pyramidal cell layer of rat cerebral cortex, but only rarely in the subcortical areas, possibly because of the use of one enzyme system in two different histochemical procedures. This limitation of the double-staining technique prompted us to demonstrate an alternate combination of HRP tracing and immunohistochemistry in the second set of experiments by employing two previously described independent enzyme systems: HRP as a retrograde tracer and beta-galactosidase as a marker for immunohistochemical demonstration of CRF. A homogeneous blue reaction product indicated immuno-beta-galactosidase staining, and a granular black or brown reaction product labeled retrogradely transported HRP in double-labeled cells in subcortical regions. Neither double labeling nor "false" double labeling was seen in pyramidal cells of cerebral cortex. These findings suggest that application of two independent enzyme systems in a combined HRP and immunohistochemical method may be useful for investigating in origins of peptidergic fibers in brain when the combination of HRP histochemistry and the PAP method appears to be inappropriate.

Animals↗
PubMed1988

Distribution and morphology of macrophages in palatine tonsils.

The distribution and morphology of macrophages were studied by immunohistochemical and electronmicroscopic methods in three diseases of the palatine tonsils: tonsillar hypertrophy, recurrent tonsillitis and tonsils with focal infection. We confirmed the presence of two types of macrophages in the tonsils, a monocyte-macrophage cell line and dendritic cells with subtypes, Langerhans' and interdigitating reticulum cells. In the lymphoepithelial symbiosis area and in the subepithelial area, the monocyte-macrophage cells and the dendritic cells had similar distributions and densities. Since these two types of cells were sometimes in contact with each other, they may function in close cooperation. In tonsils with focal infection, there were fewer dendritic cells in the lymphoepithelial symbiosis area, and the germinal centers were less well developed than in the other tonsillar diseases. These findings suggest that in tonsils with focal infection, insufficient amounts of antigen may be presented by the dendritic cells to helper T-lymphocytes.

Adolescent↗
PubMed1988

Weibel-Palade bodies in endothelial cells of normal thoracic ducts and deep cervical lymphatics in rabbits.

The endothelial cells of normal thoracic ducts and deep cervical lymphatics were examined by electron microscopy using conventional staining methods and acid-phosphatase and ruthenium red (RR) reactions. The endothelial cells contained rod-shaped, circular and elliptical bodies of moderate density. The shape and structure of all these bodies were the same as those of the Weibel-Palade bodies (WPB) in the endothelial cells of blood vessels. They were usually found near the Golgi complex in groups, and the long axis of the rods paralleled the Golgi saccules. In addition, a peculiar vacuolated rod with a bulge was found adjacent to the WPB. Single coated vacuoles were occasionally located next to the WPB. Acid-phosphatase activity and RR positive material were not seen in the WPB and the vacuoles. Our observations suggest that the WPB have a close relationship, morphological as well as functional, to the Golgi complex in lymphatic endothelial cells.

Animals↗
PubMed1987

Fine structure and morphometric analysis of lymphatic capillaries in the developing corpus luteum of the rabbit.

The fine distribution and ultrastructural changes in the intraovarian lymphatics were studied in the developing corpus luteum of rabbits. Three days after human chorionic gonadotropin (HCG) injection, lymphatic capillaries were observed among theca lutein but not granulosa cells. This distribution persisted even on day 14. Edema appeared around the lymphatic capillaries, corresponding to dilatation of blood capillaries surrounding the membrana granulosa. The diameter and perimeter of the latter vessels were about 5 times greater than before HCG injection. Lymphatic capillaries were slightly dilated and about 2 times their original diameter and perimeter. Flocculent material migrated into the lumen of the lymphatics through the open junctions. Lysosomes and rough endoplasmic reticulum were increased in number in the lymphatic endothelial cells. Five and 7 days after HCG injection macrophages and sometimes loose, degenerated lutein cells were observed in the lymphatic capillaries. Fourteen days after HCG injection, the dilatation of blood capillaries disappeared, although lymphatic capillaries remained slightly dilated after day 3. Some lymphatic but not blood vascular endothelial cells began to degenerate. The results suggest that lymphatic capillaries function to absorb and transport excess fluid and "hormones" in association with changes in ultrastructure.

Animals↗
PubMed1987

[An ultrastructural study of the rabbit intraovarian lymphatic capillaries after ovulatory stimulus].

Fine distribution and ultrastructural changes in intraovarian lymphatics were studied at accurately timed intervals after the injection of human chorionic gonadotropin (hCG). Four and six hours after hCG injection, edema around the lymphatic capillaries in the theca externa followed that around the blood capillaries. The lymphatic capillaries were markedly dilated and displayed wide openings between neighboring endothelial cells in them. At these stages, lysosome disappeared from the lymphatic endothelium, while macrophages with numerous lysosomes appeared around the lymphatic capillaries and some of them entered the lumen. Eight hours after hCG injection, the ultrastructure of the lymphatic capillaries resumed the appearance of their pre-injection stage. Three days after hCG injection, lymphatic capillaries were observed among the theca lutein cells, but not among the granulosa lutein cells. Edema around the lymphatic capillaries and openings between neighboring endothelial cells reappeared as shown 4 and 6 hours after hCG injection. Five and seven days after hCG injection, macrophages and degenerated lutein cells were observed in the lymphatic capillaries. Fourteen days after hCG injection, lymphatic endothelium began to degenerate, but that of the blood capillaries showed no degenerative signs. These results suggest that the functions of the lymphatic capillaries are absorption and transport of excess fluid, waste products and hormones.

Animals↗
PubMed1986

Lymphatic capillaries in rabbit ovaries during ovulation: an ultrastructural study.

The fine distribution and ultrastructural changes of rabbit intraovarian lymphatics and blood vessels were compared in specimens obtained at accurately timed intervals after the injection of human chorionic gonadotropin (HCG). At four and six hours after HCG injection, edema was observed around blood capillaries with a slight increase in the number of small fenestrae in the theca interna. Edema around the lymphatic capillaries in the theca externa occurred a little later. The lymphatic capillaries were markedly dilated with occasional wide openings between adjacent cells. At this stage, lysosome disappeared in the endothelial cells of the lymphatic capillaries, and macrophages with numerous peculiar lysosomes appeared around the lymphatic capillaries and some of them entered into the lumen. By eight hours after HCG injection, the edema around the lymphatic capillaries had disappeared. The form and structure of the lymphatic capillaries resumed their pre-injection appearance, but the blood capillaries showed large gaps or perforations in the endothelium. At 11 and 18 hours after HCG injection, blood capillaries had penetrated into the membrana granulosa, but lymphatic capillaries had not. Thus, the lymphatics appear to be modified at four and six hours after HCG injection and these modifications are consistent with the removal of edematous fluid.

Animals↗
PubMed1985

The calcitonin gene-related peptide-containing fiber projection from the hypothalamus to the lateral septal area including its fine structures.

The afferent source of calcitonin gene-related peptide-like immunoreactive (CGRPI) fibers in the lateral septal area of the rat was sought by using indirect immunofluorescence technique. These fibers decreased markedly on the operated side after the destruction of the area between the anterior hypothalamic nucleus and the lateral hypothalamus where there were a number of CGRPI cells. We also examined the fine structure of CGRPI fibers in the lateral septal area. Many CGRPI fibers forming axosomatic synapses were identified. These facts strongly suggest that CGRPI cells in the area between the anterior hypothalamic nucleus and the lateral hypothalamus project ipsilaterally to the lateral septal area and directly influence the soma there.

Animals↗