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Biomedical subjects

S Ferri

Publications and source records attributed to S Ferri.

At least 163 records · Page 9Linked to original sources
PubMed1980

Lysosomal enhancement in hepatic cells of a teleost fish induced by cadmium.

The toxic effects of cadmium upon the hepatic cells of a freshwater fish were studied. The experiment was developed by the addition of cadmium chloride in the water and histochemical and EM methods were performed. The results showed that acute intoxication induces an increase of lysosomal activity related to the shape, distribution as well as different functional degrees of the organelle condensation. The authors analyze the different situations whose leading alterations of lysosomal behaviour and the probable mechanisms of cadmium action.

Acid Phosphatase↗
PubMed1980

Fine structure of a freshwater teleost (Pimelodus maculatus) hepatocytes revealed by ultrathin sections.

The hepatocytes of Pimelodus maculatus studied in thin sections revealed: 1. 3 physiological surfaces: a) in content with the Disse's space; b) in contact with neighboring hepatocytes; and c) showing grooves that delimit bile canaliculi; 2. bile canaliculi presenting, sometimes, intracellular diverticula; 3. junctional complexes joining hepatocytes close to the bile canaliculi; 4. gap junctions in great number; 5. a characteristic feature of the RER; 6. a commonly close relationship between mitochondria and RER; 7. Golgi complexes near the bile canaliculi and in the perinuclear area; 8. smooth endoplasmic reticulum, lysosomes, glycogen and lipids in small amounts.

Animals↗
PubMed1980

Elastic system fibers (oxytalan, elaunin and elastic fibers) in the skin of a freshwater teleost : optical and electron microscopy study.

The oxytalan, elaunin and elastic fibers which represent a system of connective tissue fibers -- the elastic system (ESP) -- were studied in the dermis of a teleost by optical and electron microscopy. The oxytalan fibers were identified at the dermo-epidermal junction. They are bound, by one of their extremities to the basal lamina, and by the other are in continuity with elaunin fibers. The elaunin fibers cross the entire stratum compactum perpendicularly and in the deeper zone are interconnected to other elaunin fibers. Thick elastic fibers, forming an apparent continuous layer were observed between the stratum compactum and the stratum spongiosum. The ultrastructural characteristics and functional properties of the ESF are discussed.

Animals↗
PubMed1980

Fine structural analysis of a teleost exocrine pancreas cellular components - a freeze-fracture and transmission electron microscopic study.

The normal exocrine pancreas of Pimelodus maculatus (Teleostei) has been studied by freeze-fracture and conventional transmission electron microscopy. 4 cellular types in the acini are observed: the acinar cells, the argentaffin cells, the intermediate cells and the centroacinar cells. The most proeminent cytoplasmic feature of the acinar cells is that the well developed rough endoplasmic reticulum, which appear predominantly under the vesicular form. The argentaffin cells are found lodged between the acinar cells and duct cells, in the connective tissue they are isolated principally that surrounds the ducts. The typical granules are the cytoplasmic component wich characterize the argentaffin cells. The indermediate cells are characterized by the presence of two distinct granule types: one resembling that found in the endocrine cells and the other resembling the granules of the acinar cells. The centroacinar cells is similar that found in other species.

Animals↗
PubMed1979

Prostaglandins in the brain of rats given, acutely, and chronically, a hyperthermic dose of met-enkephalin.

An enhanced prostaglandinlike activity is shown in homogenates of brain from rats treated intracerebroventricularly with 100 microgram of metenkephalin. The increase is significantly reduced by naloxone pretreatment. A relationship is proposed between generation of prostaglandins in the brain following met-enkephalin administration and hyperthermic effect of the opiatelike factor in the rat. Normalization of prostaglandinlike activity following chronic administration of met-enkephalin in the rat may also account for the development of tolerance to its thermic effect.

Animals↗
PubMed1979

Prostaglandins in rat placenta following acute and chronic administration of morphine.

The objective of the present study was to obtain information on prostaglandin (PG) biosynthesis in placenta following narcotic administration. PG biosynthetic capacity was determined in whole rat placenta homogenates in the presence of Na arachidonate, by evaluating net production of PGs assayed against PGE1 on rat stomach strips. An enhanced prostaglandin-like activity is shown in homogenates of placenta from rats treated subcutaneously with 10 mg/kg of morphine. This increase was prevented by naloxone pre-treatment. Continual morphine administration during gestation, results in a normalization of placental biosynthetic capacity thus suggesting the development of a tolerance to the narcotic effect.

Animals↗
PubMed1979

Freeze-fracture study of the epidermal cells of a teleost with particular reference to intercellular junctions and permeability to tracer.

The plasmatic membranes, the intercellular junctions and the intercellular spaces of the epidermis of the fish Pimelodus maculatus were studied by freeze-fracture and by lanthanum methods. The observations has confirmed the presence of desmosomes. Gap junctions were not found and the tight junctions can be seen very rarely, arranged to form small discrete maculae. The finger-print pattern due to the microridges of the apical plasma membrane of the superficial cells was studied by direct replicas. The tracer penetrates all the intercellular epidermal spaces but failed to penetrate the dermis, suggesting the presence of a barrier at the dermo-epidermal level.

Animals↗
PubMed1978

Effects of Met-enkephalin on body temperature of normal and morphine-tolerant rats.

The endogenous opioid met-enkephalin intraventricularly adminstered to the rat at the dose of 100 microgram raised rectal temperature, whereas 400 microgram of the pentapeptide caused a diphasic effect, i.e., hypothermia followed by hyperthermia. Met-enkephalin was ineffective when administered i.p. The effects on temperature were substantially similar to those elicited, for both routes of administration, by morphine, which may either raise or lower rat temperature depending on the dose. More naloxone was required to antagonize thermic effects of met-enkephalin than morphine. Finally, there was a lack of effects on temperature for met-enkephalin centrally administered to morphine-tolerant animals, thus providing further evidence, in vivo, of cross tolerance between opiates and naturally occurring ligands of opiate receptors.

Animals↗
PubMed1978

Changes in liver tyrosine aminotransferase after acute and chronic administration of morphine in the rat.

Acute administration of Morphine (20 mg/kg/s.c.) in the rat results in a rise of liver tyrosine aminotransferase (TAT) expressed as mumoles of p-hydroxyphenylpyruvate/100 mg/h. With chronic administration, a tolerance develops to this enzymatic effect. TAT induction is not evident in pregnant rats, given the narcotic, in which enzyme levels are already initially high. After delivery TAT returns to normal levels and it is possible to show both induction and tolerance developing to morphine. Enzyme activity in fetal livers is much lower than that of adult animals: after maternal administration of morphine only a modest TAT increase is seen which is not, however, statistically significant. TAT activity is fully evident in livers of offspring, with much higher mean levels in newborn rats from morphine-treated animals, as a possible consequence of morphine deprivation. In this latter group of newborn rats narcotic administration causes TAT activity to return to levels as high as those of naive animals. On the other hand, morphine administration to the prole of naive rats results in an induction of liver TAT.

Animals↗