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Biomedical subjects

F Orlandi

Publications and source records attributed to F Orlandi.

At least 127 records · Page 7Linked to original sources
PubMed1979

Effects of sulpiride isomers on the control of anterior pituitary secretion in normal man.

The effects of (+)- and (-)-sulpiride on anterior pituitary hormone secretion (LH, FSH, PL, hGH, TSH) have been studied in five normal men. Both (+)- and (-)-sulpiride increase PL and TSH secretion and decrease LH and FSH secretion, whereas they do not seem to affect hGH secretion. These results are discussed in view of the different action of (+)- and (-)-sulpiride on DA receptors in the forebrain with respect to DA receptors involved in the control of anterior pituitary secretion.

Adult↗
PubMed1978

A stereological and biochemical study of the human liver in uncomplicated cholelithiasis.

A quantitative analysis of needle liver biopsies of patients with untreated, uncomplicated cholelithiasis has been performed to better evaluate eventual changes occurring under medical therapy of gallstones. With the light microscope, the intensity of parenchymal steatosis was variable among the patients but the mean volume density of lipid droplets was significantly increased as compared to normal subjects. In addition, there was a significant increase in the volume density of lipocytes (fat-storing cells) without an increase in the number per square area, suggesting a hypertrophy of individual cells. The data obtained by ultrastructural morphometry show a significant increase in the surface density of the rough endoplasmic reticulum in the hepatocytes, a significant increase of the mitochondrial volume density together with the presence of curled mitochondrial cristae and a slight, inconstant intracellular and intracanalicular bile retention. No qualitative or quantitative changes were observed at the level of the smooth endoplasmic reticulum. The activity of the microsomal enzyme NADPH-cytochrome c reductase as evaluated on liver biopsy material was in the normal range. Some of the features observed in this group of patients are reminiscent of alterations previously described in human or experimental cholestasis and suggest that they might depend on a common underlying disturbance in cholesterol and bile salt metabolism.

Adolescent↗
PubMed1975

Hepatic cholesterol synthesis in man: effect of diazepam and other drugs.

The hepatic synthesis of cholesterol-measured as incorporation of 14C-acetate into digitonin-precipitable sterols-has been evaluated in needle biopsy material of normal untreated patients and patients under short-term treatment with Diazepam, Phenobarbital, Chlorpromazine or Diphenylhydantoin. A significant increase of cholesterol synthesis was observed in the first two groups with much higher levels of incorporation in the Diazepam-treated patients. Moreover in this group the levels were still elevated from 4 to 7 days after drug withdrawl. Ultrastructural and morphometric studies performed on the same biopsy material showed a significant increase of smooth endoplasmic reticulum in hepatocytes of Diazepam-treated patients; in addition, there seemed to be a positive correlation between the increased cholesterol synthesis and the formation of areas of non vesicular, type 2, smooth endoplasmic reticulum. These findings suggest an early stimulation of the liver cell microsomal system by Diazepam in man; they also point to side effects of some drugs, which are not predictable from studies in Wistar rats.

Acetates↗
PubMed1974

A morphometric study of the endoplasmic reticulum in human hepatocytes. Correlation between morphological and biochemical data in subjects under treatment with certain drugs.

The distribution of the endoplasmic reticulum in human hepatocytes is defined in quantitative terms using the techniques of morphometry. The subjects of the study are liver biopsies from normal, untreated subjects and patients being treated with various drugs. In contrast to rat hepatocytes, the amount of smooth endoplasmic reticulum (SER) in man exceeds that of the rough endoplasmic reticulum (RER) and accounts for 76.3% of the total endoplasmic reticulum. This is to be taken into consideration in pharmacological or toxicological studies. In addition, two components of the SER have been identified: more prominent is the type 1 or vesicular which has a regular honeycomb pattern, made up of cisternae with patent lumina and a mean width of 1500 A; the type 2, or non-vesicular, occurs in discrete foci of densely packed smooth membranes with a spacing of about 140 A. In subjects under short-term treatment with Benzodiazepin (diazepam) the RER remained unchanged but the SER membranes were significantly increased with a remarkable, two-to threefold increase of the SER type 2 in three out of four patients. A rise in incorporation of (14)C-acetate into digitonin-precipitable sterols as measured in liver biopsy material was also noted in these three patients. The suggestion is made that the SER 2 represents the newly formed membranes whereas the SER 1 would represent ;adult' membranes. No changes were observed in two patients under short-term treatment with phenobarbital or Dilantin.

Biopsy↗
PubMed1971

Changes of the smooth endoplasmic reticulum induced by rifampicin in human and guinea-pig hepatocytes.

Rifampicin induces a proliferation of the smooth endoplasmic reticulum in guinea-pig and human hepatocytes. This may support the hypothesis of enhancement of drug-metabolizing enzymes induced by the drug. However, the pattern of proliferation is not similar in man and in guinea-pig hepatocytes. Some caution is needed in the study of enzyme induction in man and in extrapolations from animal to human data.

Animals↗