Biomedical subjects
Publications and source records attributed to M Mazzoni.
Renal oncocytoma is an uncommon benign neoplasm of tubular epithelial origin. It usually occurs as single mass and clinically may be confused with renal cell carcinoma. Angiographic, CT and ultrasound studies may suggest the diagnosis but they are not pathognomonic. The clinical, diagnostic and anatomopathological features of two cases are presented and discussed.
The incorporation of phosphatidyl[2-3H]inositol ([3H]PI) from vesicles or microsomal membranes into rat liver nuclei is greatly stimulated by phosphatidylinositol transfer protein (PI-TP). The nuclei are able to phosphorylate [3H]PI, with the production of phosphatidylinositol 4-phosphate (PIP). Recovery of tritiated inositol trisphosphate, inositol phosphate, glycerophosphoinositol and inositol, suggests that in isolated nuclei a large set of enzymes of the PI cycle is present, similar to the enzymes involved in the plasma membrane PI cycle. Incubation with [gamma-32P]ATP shows that isolated nuclei are able to phosphorylate endogenous PI to PIP and phosphatidylinositol 4,5-bisphosphate (PIP2). In the presence of exogenous PI and detergent the synthesis of PIP is increased, indicating that in nuclei the PI pool is suboptimal for the PI-kinase activity. The present study suggests that PI-TP may be involved in providing substrates for PI metabolism at the nuclear level.
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Subcellular distribution of inositol lipids has been studied in Friend Erythroleukemia Cells following induction to erythroid differentiation with hexamethylenebisacetamide, after labelling with [3H]myo-inositol. In situ autoradiography indicated that inositol-derived molecules were present also in the nuclear compartment of uninduced and induced cells. Fractionation studies showed that the nuclear polyphosphoinositides were deeply changed after short induction times, while the whole cell inositol lipids resulted only slightly modified by the inducer. The nuclear recovery of phosphatidylinositol 4,5-bisphosphate was largely increased after 2 hrs of induction, suggesting that inositol lipid metabolism is involved in the early differentiation events occurring at the nuclear level.
A case of Gerstmann syndrome following a trauma is presented. After one month the patient showed the four symptoms of the Gerstmann syndrome associated with slight visual memory and constructional praxis deficits. Eight months later, however, he showed only dyscalculia, dysgraphia, right-left disorientation and finger agnosia, in accordance with selective damage of the left angular gyrus revealed by CT scan. The findings seems to support the existence and the localizing value of Gerstmann syndrome.
The molecular basis of the interaction between the visual receptor, rhodopsin, and the rod outer segment GTP-binding protein, transducin or Gt, was studied using a synthetic-peptide-competition approach to elucidate the site(s) on the Gt alpha-subunit (alpha t) involved in high-affinity binding to light-activated rhodopsin (R*). Synthetic peptides based on the amino acid sequence of portions of the molecule that interact with rhodopsin can themselves bind the rhodopsin and thus behave as competitive inhibitors of rhodopsin-G-protein interaction. This blockade was assessed by measuring the ability of peptides to inhibit Gt stabilization of the metarhodopsin II conformation of rhodopsin. Based upon this analysis, two regions near the C-terminal of alpha 1 are important for interaction with R*.
Isolated rat liver nuclei and subnuclear fractions synthesize polyphosphoinositides in vitro in a mode dependent on the presence of nuclear membrane, detergent and exogenous substrates. The nuclear membrane is not essential as a source of lipid kinases, since the addition of exogenous phosphatidylinositol or phosphatidylinositol monophosphate to reaction mixtures lacking membranes restores the synthesis of phosphatidylinositol mono- and bisphosphate, respectively. Inositide phosphorylation is best accomplished by high-salt extracted nuclei and pre-detergent lamina. These data suggest that the nucleus, and especially the nuclear periphery, is a cell compartment in which polyphosphoinositide synthesis occurs; this might be related to the progression of phosphatidylinositol metabolism-dependent signals to the genetic apparatus.
We report a case of acute CO poisoning, followed after 9 days by the onset of choreoathetosis in the upper limbs and face, in a 24 year old man. The patient also showed memory disturbances that tended to clear gradually within about six months. CT scan and NMR revealed symmetrical bilateral lesions in the globus pallidus.
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Two different techniques of reconstruction after total gastrectomy were performed in rats: Roux-en-Y (RY) and jejunal interposition (JI). Sham-operated rats were used as controls. Sixteen weeks after surgery the animals were sacrificed. The distribution of the enteroendocrine cells in the duodenal and proximal jejunal mucosa was examined using the Grimelius silver nitrate stain. The frequency of the Grimelius-positive cells was estimated as number of cells per square millimeter of gut surface and as number of cells per transverse section of intestine. Intestinal villi height was also measured in the same duodenojejunal tracts. After gastrectomy, the JI rats showed a better weight gain than RY rats (p less than 0.05). A significant difference in the distribution of intestinal argyrophil cells was seen. The bypassed duodenojejunal tracts in RY rats showed a marked reduction of the Grimelius-positive cells in comparison with JI rats and controls (p less than 0.01). A reduction in the number of argyrophil cells in the proximal duodenum was also noticed in the JI rats in comparison with controls (p less than 0.01). A decrease in the villi height resulted in all the gastrectomized rats (p less than 0.01), but a significant decrease was also noticed in RY rats in comparison with JI (p less than 0.01). Our experimental observations suggested that the exclusion of the duodenum from intestinal transit after gastrectomy caused atrophy of the gut mucosa and a marked reduction in the number of argyrophil enteroendocrine cells in the bypassed tracts.
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Several 4-benzoyl- and 4-benzyl-1,2,3-triazol-N-acetic derivatives were synthesized and tested. The compounds were prepared by nucleophilic substitution, 1,3-dipolar cycloaddition and usual functional group conversion reactions. Numerous derivatives were evaluated in vitro for their ability to inhibit the prostaglandin synthesis and to displace labelled [14C]indomethacin from bovine vesicular gland microsomes. Some compounds showed biological activity.
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In microsurgery of the middle ear using argon laser, heat is produced on the sensorineural structures adjacent to the irradiated bones. Thermal gradients following laser applications have been measured by means of special thermocouples. The footplate was perforated by a 50 msec. ray applied both at 380 mWatt and at 460 mWatt. The maximum temperature increase registered in the labyrinthine spaces was respectively 2 degrees C. and 3.5 degrees C. Coagulation of the promontory mucosa was performed using 100 msec. impulses at 200 mWatt. At the end of a series of 12 applications the temperature increase at the level of the basal coil was 1.4 degrees C. From the above results the authors conclude that no damage is induced during laser microsurgery and that, considering the power and time values relative to impulses, the use of laser in routine clinical practice should be relatively safe.
Three different dissociation techniques of rat liver were compared and yield, viability and morphology of the obtained cells were evaluated. The isolation methods used in this study were: 1. Enzymatic by immersion; 2. Mechanical; 3. Enzymatic by perfusion. The first method supplied 3.91 +/- 1.67 X 10(6) cells/g tissue (X +/- Standard Deviation) and a viability of 52.8 +/- 24.3%. The second method supplied 25.9 +/- 5.68 X 10(6) cells/g tissue and a viability of 62.3 +/- 18.6%. The third method supplied 50.5 +/- 26.6 X 10(6) cells/g tissue and a viability of 87 +/- 5.6%. The hepatocytes obtained according to the three methods were then transplanted into the spleen of allogeneic rats after partial hepatectomy. Allotransplantation of hepatocytes in partially hepatectomized rats proved to inhibit remaining liver regeneration in comparison to partially hepatectomized control rats using mechanically isolated hepatocytes (p less than 0.05), while the allotransplantation of hepatocytes obtained by the two enzymatic methods did not modify significantly liver regeneration.
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