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S Agostini

Publications and source records attributed to S Agostini.

At least 55 records · Page 3Linked to original sources
PubMed1988

Relationship between transient DNA hypomethylation and erythroid differentiation of murine erythroleukemia cells.

The state of DNA methylation in mouse erythroleukemia (MEL) cells has been analyzed in relation to commitment to differentiation in response to treatment with hexamethylenebisacetamide (HMBA). Previous experiments have shown that induction by HMBA involves transient genome-wide hypomethylation of DNA that is achieved by replacement of 5-methylcytosine with cytosine residues. The experiments described in the present communication revealed that hypomethylation is a very early event in the process of differentiation. Exposure of the cells to 3-deazaadenosine, an adenosine analog, in combination with homocysteine, resulted in the intracellular accumulation of 3-deazaadenosylhomocysteine, which caused an inhibition of HMBA-induced hypomethylation that was correlated with a comparable inhibition of differentiation. While these experiments suggest that hypomethylation is a necessary step in the process of differentiation, other experiments reported here indicate that hypomethylation of DNA may be necessary but not sufficient to trigger the whole program of differentiation in MEL cells. We found, for example that exposure of the cells to cycloheximide during the first 24 hr of induction by HMBA resulted in complete inhibition of differentiation without significant effect on the HMBA-induced hypomethylation. This result also indicates that the enzymatic machinery required for the hypomethylation of DNA is present in uninduced cells.

Acetamides↗
PubMed1988

[Value of MRI in the study of hepatocellular carcinoma. Preliminary study apropos of 12 cases].

The authors have tested different MR imaging sequences to detect hepatocellular carcinomas. The most performing is a spin-echo T2-weighted sequence with long TR (1800 or 2000 ms), and three echoes. The first echo, early at 40 ms, may allow an analysis of the vessels, later, at 80 and 120 ms, the two other echoes permit a better visualization of the tumor. With this type of sequence, the method's sensibility is excellent.

Carcinoma, Hepatocellular↗
PubMed1987

[Fine-needle cyto-puncture. Apropos of 138 liver cytologies and 66 pancreas cytologies].

In this report, we examined the sensitivity and specificity of 138 hepatic and 66 pancreatic fine needle aspiration cytology. Aspiration cytodiagnosis was performed using a fine needle, percutaneously, with ultrasonic or tomodensitometric guidance. Sensitivity of hepatic and pancreatic aspiration cytodiagnosis was 86.73% et 83.3%; specificity was respectively 97.72% an 100%. These results are compared with literature review and confirm the interest of fine needle aspiration cytology in tumoral pathology.

Adenocarcinoma↗
PubMed1987

[Retro-pancreatic inflammatory pseudotumor].

The authors report a case of retro-pancreatic tumor in a 65 year-old man associated with impaired general condition. At gross examination by the surgeon, the pancreatic gland seemed to be enlarged. Histologic analysis found fibrous tissue and inflammation with lymphoid cells. The diagnosis of inflammatory pseudotumor was based on similar aspects found in some orbital lesions. The "tumor" disappeared under steroid therapy but recurred as soon as the treatment was stopped. Several etiologic factors related to the unusual location of the lesion were discussed.

Aged↗
PubMed1986

S-adenosylhomocysteinase: mechanism of reversible and irreversible inactivation by ATP, cAMP, and 2'-deoxyadenosine.

Homogeneous S-adenosylhomocysteinase (AdoHcyase) from rat liver is a tetrameric enzyme that contains four molecules of tightly bound NAD per mole of enzyme. We report here that incubation of the rat liver enzyme with ATP, Mg2+, and KCl leads to conversion of the active enzyme to an inactive form with release of all enzyme-bound NAD which can be recovered quantitatively by gel filtration. At various concentrations of ATP, the release of NAD corresponds closely with the degree of inactivation, suggesting that the four subunits are equivalent. Hydrolysis of ATP is not required for the inactivation process since nonhydrolyzable ATP analogues can replace ATP in the inactivation process. The ATP-dependent inactivation is fully reversible upon incubation of the inactivated enzyme with NAD. The ATP-dependent inactivation of the enzyme appears to be analogues to the cAMP-dependent inactivation of the enzyme from Dictyostelium discoideum described earlier by Hohman et al. (1985) [Hohman, R. J., Guitton, M. C., & Veron, M. (1985) Proc. Natl. Acad. Sci. U.S.A. 82, 4578-4581; Hohman, R. J., Veron, M., & Guitton, M. C. (1985) Curr. Top. Cell. Regul. 26, 233-245] but differs from the irreversible inactivation studied earlier by Abeles et al. (1982) [Abeles, R. H., Fish, S., & Lapinskas, B. (1982) Biochemistry 21, 5557-5562]. These authors have ascribed the time-dependent inactivation that results from incubation of the enzyme with 2'-deoxyadenosine at the C-3' and concluded that AdoHcyase "probably consists of two nonequivalent pairs of subunits".(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1986

[Hepatic rupture. Wrapping with absorbable mesh].

Considerable progress in conservative surgery of the spleen and kidney has been achieved in recent years by wrapping the organ in absorbable mesh. Following an experimental study, this technique has been used in 5 cases of rupture of the liver. Each injured lobe can be wrapped in an absorbable prosthetic sheet which is sutured in such a way as to form a purse applied onto the tissue, to control bleeding and bile leakage. The purse is then sutured to the falciform ligament detached from the diaphragm. Under drainage and provided the liver is watched for cavitation by scanning methods, this technique is simple and consistently effective. It avoids sutures, which are imperfect, and resections, which are fraught with dangers when performed in an emergency.

Humans↗
PubMed1986

[Compression of the right pulmonary artery by a dissecting aneurysm of the ascending aorta. Value of x-ray computed tomography].

Right pulmonary artery compression by a dissecting aortic aneurysm-value of computed tomography. The authors relate a case of dissecting aortic aneurysm occurring as a late complication of aortic valve replacement and causing right pulmonary artery compression. Computed tomography appears to be performing technique for the exploration of this unusual case.

Aortic Dissection↗
PubMed1985

Interaction of tryptophan with lecithin liposomes: NMR and turbidity studies.

A study on the interactions between tryptophan (Trp) and dipalmitoylphosphatidyl choline (DPPC) liposomes conducted with the NMR technique and taking turbidity measurements is reported. Trp is shown to be incorporated into the bilayer only when interaction occurs above gel-liquid transition. Disappearance of turbidity changes at the phase transition temperatures are shown to occur with Trp incorporation. 1H and 13C NMR relaxation times T1 of DPPC are seen to be reduced. Acyl chain signal intensity is shown to decrease and the corresponding line-width to increase as a function of Trp concentration. DPPC 31P [1H] Nuclear Overhauser Effect (NOE) is depressed by the presence of Trp above gel-liquid transition temperature whereas NOE remains high below phase transition temperature when Trp is present in the bilayer. Effects are shown to be the same in both H2O and in 2H2O. A membrane modification that may account for the previously observed inhibition of polysaccharide induced cell aggregation is hypothesized.

Kinetics↗
PubMed1985

Lesions of the spine in heroin addicts.

The authors present 6 cases of spinal lesions in heroin addicts--3 infective, 3 traumatic. The striking feature about all these cases is the comparative absence of spinal symptoms. This underlines the importance of accurate and early diagnosis in these subjects.

Adolescent↗
PubMed1983

Scoliosis due to rib osteoblastoma: report of two cases.

Two cases of osteoblastoma of a rib associated with progressive scoliosis are reported. The unusual localization of the neoplastic lesions and their close relationship to the lateral deviation of the spine suggest an etiologic basis for these patients' scoliosis. The need for early diagnosis and surgical excision of the rib lesion in the treatment of scoliosis resulting from osteoblastoma of a rib is stressed.

Bone Neoplasms↗
PubMed1983

Relationship between rib hump deformity and vertebral rotation in idiopathic scoliosis.

The authors advance the theory that there are two distinct groups of idiopathic scoliosis, of different aetiology and with different potential for development. This is based on the relationship between vertebral rotation and wedge deformity of the vertebral bodies. The rotatory type can be identified, to a statistically significant extent, in the initial phases of thoracic scoliosis. In order to test this hypothesis, we therefore confined our study to cases in which the initial Cobb angle was less than 20 degrees.

Adolescent↗
PubMed1983

A case of progressive scoliosis in a patient with craniocleidopelvic dysostosis.

The authors describe a case of craniocleidopelvic dysostosis in a patient with progressive scoliosis. They attribute the pathogenesis of the vertebral deformity to imbalance of the shoulder girdle muscles and dysplasia of the vertebral metameres. They agree with the majority of authors in regarding craniocleidopelvic dysostosis as a specific clinical manifestation of a complex hereditary syndrome.

Bone Diseases↗
PubMedDate not supplied

Idiopathic muscular hypertrophy of the esophagus: CT features.

Idiopathic muscular hypertrophy of the esophagus is a rare, benign esophageal disease, characterized by hyperplasia of all layers of the wall and, in particular, muscle layers. The authors describe the CT findings and review the relevant literature.

Adult↗