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Biomedical subjects

L Beretta

Publications and source records attributed to L Beretta.

At least 91 records · Page 5Linked to original sources
PubMed1989

[Clinical aspects, diagnosis and therapy of thrombosis of an abdominal aortic aneurysm].

In a consecutive series of 640 surgically treated abdominal aortic aneurysms, 4 patients affected by thrombosis of the abdominal aortic aneurysm were observed. All aneurysms were five centimeters in diameter or smaller and all the patients complained of chronic claudication. In spite of the old opinion that considered abdominal aneurysmal thrombosis an useful event, we believe that the angiographic and clinical picture of juxta-renal aortic occlusion points to surgical treatment.

Aged↗
PubMed1989

A single cDNA encodes two isoforms of stathmin, a developmentally regulated neuron-enriched phosphoprotein.

Stathmin, a 19-kDa neuron-enriched soluble phosphoprotein, has been recently proposed as an ubiquitous intracellular relay for the diverse extracellular signals regulating cell proliferation, differentiation, and functions through various second messenger pathways (Sobel, A., Boutterin, M.C., Beretta, L., Chneiweiss, H., Doye, V., and peyro-Saint-Paul, H. (1989) J. Biol. Chem. 264, 3765-3772). Internal sequences of the protein from rat brain were determined after purification by two-dimensional polyacrylamide gel electrophoresis, electrotransfer onto Immobilon, and in situ proteolysis. Oligonucleotide mixtures based on these sequences were used to clone a cDNA for stathmin from a rat PC12 cell lambda gt 10 library. The deduced amino acid sequence reveals partial homologies with the coiled coil structural regions of several intracellular matrix phosphoproteins. Using this cDNA as a probe, we show that the expression of stathmin mRNA parallels that of the protein during brain ontogenesis, reaching a maximum at the neonatal stage. In vitro translation of the derived cRNA yielded all the known molecular forms of stathmin, namely its alpha and beta isoforms in their unphosphorylated and phosphorylated states. Thus, a single cDNA codes for both biologically relevant isoforms of the protein, indicating that they differ by co- or post-translational modifications.

Adrenal Gland Neoplasms↗
PubMed1989

Identification of two distinct isoforms of stathmin and characterization of their respective phosphorylated forms.

Stathmin is a ubiquitous soluble protein (Mr approximately 19,000, pI approximately 6.2-5.5) whose phosphorylation is associated with the intracellular mechanisms involved in the regulations of cell differentiation and functions by extracellular effectors. Its purification from rat brain and the preparation of specific antibodies allowed us to identify a set of immunologically related unphosphorylated (N1, N2) and phosphorylated (P1, P2a, P2b, P3) proteins of decreasing isoelectric points. All these proteins yielded identical silver-stained or 32P-radioactive peptide maps with the protease V8 from Staphylococcus aureus, indicating that they are also structurally related. In vitro phosphorylation with the exogenous catalytic subunit of the cAMP-dependent protein kinase, as well as dephosphorylation with alkaline phosphatase, indicated that P1, P2, and P3 derived from N1 and N2 by progressive phosphorylation. Phosphorylation of individual proteins extracted from semi-preparative two-dimensional polyacrylamide gels demonstrated the existence of two distinct isoforms of stathmin, alpha and beta: N1 and N2 are their respective unphosphorylated forms (alpha O and beta O), whereas proteins P1-P3 could be resolved as at least three increasingly phosphorylated forms of both alpha and beta stathmin (alpha 1, alpha 2, alpha(3) and beta 1, beta 2, beta(3]. In intact pituitary GH4C1 cells, hormones like thyrotropin-releasing hormone and vasoactive intestinal peptide induced a similar conversion from N1 and N2 to P1, P2, and P3. The phosphorylation of both alpha and beta isoforms of stathmin is therefore a physiologically significant response to specific extracellular regulatory agents. In conclusion, stathmin represents a family of at least two distinct protein isoforms, whose respective phosphorylation and expression might play a role in its likely function as an intracellular relay of various converging extracellular signals.

Alkaline Phosphatase↗
PubMed1989

[A rare case of aneurysm of the superficial femoral artery with dysplasic etiology].

The most frequent localisation of fibrous dysplasia of the arteries is at the renal arteries. Other localisations are rarer and those at the femoral as in the case described are exceptional. The case was observed in a 21-year-old woman who, in the absence of any previous traumatism and septic state, noticed the onset of a pulsating tumefaction at thigh level. Echography and arteriography showed the tumefaction to be an aneurysm of a collateral of the superficial femoral artery at the lower IIIrd of the thigh with the dimensions of a pigeon's egg. The aneurysm was successfully removed without the need for grafts and subsequent histological examination showed it was secondary to fibrous dysplasia. The rarity of such a clinical case is stressed.

Adult↗
PubMed1989

Intracellular substrates for extracellular signaling. Characterization of a ubiquitous, neuron-enriched phosphoprotein (stathmin).

We previously identified (Sobel, A., and Tashjian, A. H., Jr. (1983) J. Biol. Chem. 258, 10312-10324) a group of cytoplasmic proteins whose phosphorylation could be related to the regulation by extracellular effectors of cells as different as pituitary and muscle cells. Among these phosphoproteins, proteins "7" and "8" (Mr approximately 19,000, pI approximately 5.8-6.0), that we now designate P1 and P2, are very abundant in rat brain. Partial purification of these proteins was therefore achieved after 100 degrees C precipitation of a rat brain-soluble fraction and further fractionation of the supernatant by ion exchange chromatography. Several related non-phosphorylated (N1, N2) and phosphorylated (P3) proteins were also identified in the heat-resistant supernatant. Antisera raised against P2 extracted from nitrocellulose blots of semipreparative two-dimensional gels recognized all the proteins N1, N2, P1, P2, and P3, confirming that they belong to the same protein family, and suggesting that they are likely various forms of a single protein core. The same protein could be detected biochemically and immunologically at various concentrations in all the tissues or cell types from diverse mammalian and nonmammalian species tested. Together with our previous data relating its phosphorylation to the regulation of the proliferation, differentiation, and/or the functions of the cells considered, this observation leads us to suggest that it might be an ubiquitous regulatory phosphoprotein playing the role of an intracellular "relay" for extracellular signals, after their binding to specific membrane receptors and the generation of second messengers. We propose to name this protein stathmin, from the greek "stathmos" (relay).

Animals↗
PubMed1989

Stathmin is a major phosphoprotein and cyclic AMP-dependent protein kinase substrate in mouse brain neurons but not in astrocytes in culture: regulation during ontogenesis.

Stathmin is a ubiquitous soluble protein (Mr approximately 19,000; pI approximately 6.2-5.5) whose phosphorylation is associated with the intracellular mechanisms involved in the regulations of cell differentiation and functions by extracellular effectors. It is present in various tissues and cell types and has several nonphosphorylated and increasingly phosphorylated forms, and it is particularly abundant in brain. Very high concentrations of stathmin were also detected in mouse embryo striatal neurons grown in primary culture, whereas stathmin was barely detectable in astrocytes from the same source. Stathmin appeared in neurons as a major substrate for protein phosphorylation and, in particular, for the cyclic AMP (cAMP)-dependent protein kinase, because its phosphorylation was stimulated by cAMP in cell-free preparations and in intact cells by forskolin, a potent activator of adenylate cyclase. During brain ontogenesis, stathmin was first detected at embryonic day 12; its concentration increased until birth and then decreased from postnatal day 10 to adulthood. In parallel, its molecular forms shifted from the least phosphorylated to the more phosphorylated ones. This result may reflect the evolution of the activity of stathmin during development and the subsequent maturation of the brain. In conclusion, our results substantiate the likely role of stathmin as an intracellular relay of extracellular regulations, as they point out its specific importance related to neuronal functions and brain differentiation.

1-Methyl-3-isobutylxanthine↗
PubMed1989

Cirrhosis: diagnosis with sonographic study of the liver surface.

To find an objective sonographic sign of cirrhosis, the authors used a small-parts probe to examine the liver surface for irregularities that corresponded to those of nodular regeneration. Fifty healthy subjects were examined to assess the pattern of a sonographically normal-appearing liver surface. A second group of 75 patients, mainly with suspected diffuse chronic liver disease, was examined with particular attention to the most commonly described sonographic signs of cirrhosis, and laparoscopy and biopsy were also performed. The liver surface was examined in a third group of 225 patients with cancer in whom metastases had been demonstrated sonographically. A diagnosis of cirrhosis was made with sonography when surface irregularities were observed that were comparable to the anatomic abnormalities of a cirrhotic liver surface. An examination of the liver surface gave the best diagnostic rate for cirrhosis (88%). There were seven false-negative results, but in five of them no surface nodularity could be seen at laparoscopy, and the diagnosis was made only on the basis of histologic studies; there was one false-positive result. This study indicated that ultrasonography might be a reliable method to follow up patients with chronic liver disease that may progress to cirrhosis.

Adolescent↗
PubMed1989

Phosphorylation of a group of proteins related to the physiological, multihormonal regulations of the various cell types in the anterior pituitary gland.

We previously identified a group of cytoplasmic phosphoproteins whose phosphorylation could be related to the multihormonal regulation of PRL in the homogeneous tumor-derived GH cell lines (set of proteins 1-11) and in heterogeneous normal anterior pituitary cells in culture (set of proteins 1-15). In normal cells, a mixture of hypothalamic hormones induced, like the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, stronger phosphorylation changes than TRH alone. Proteins of the set 1-15 are therefore likely to be present also in the nonmammotrophic anterior pituitary cell types, where their phosphorylation can be regulated by the hormones specific of the cell type considered. This interpretation is confirmed by the presence of the same proteins in cells of the corticotroph-like AtT-20/D16 cell line and the regulation of their phosphorylation by CRF. The same phosphoproteins were also detected in non dissociated anterior pituitary tissue from ovariectomized rats. Their phosphorylation was regulated by various hormones and other extracellular agents in a way similar to their regulation in anterior pituitary cells in culture. A 5-day estradiol implant pretreatment of the ovariectomized rats, which stimulates the anterior pituitary gland both directly and indirectly, resulted in a very high level of basal phosphorylation of proteins 1-15. Only very little further stimulation was achieved by the addition of exogenous hypothalamic hormones, indicating that the actual physiological regulatory pathways are the same as those unraveled in the various cell culture model systems. In conclusion, phosphorylation of proteins 1-15 1) can be related to the multihormonal regulation of the various anterior pituitary cell types in culture and 2) corresponds to intracellular molecular mechanisms actually involved in the physiological regulations of pituitary functions in the intact anterior pituitary gland.

Animals↗
PubMed1989

2-substituted derivatives of benzimidazole inhibiting gastric acid secretion in rats.

Benzimidazole and its 2-derivatives with amino, carbamonitrile, urea, and guanidine groups have been tested for their activity on gastric secretory process. The carbamonitrile-, urea-, and guanidine compounds decrease gastric acid secretion, basal and stimulated with histamine or betazole, in Shay-rats and depress the guinea pig auricle activity stimulated by betazole. The results suggest that the studied 2-substituted benzimidazole compounds exhibit anti H2-histamine activity.

Animals↗
PubMed1988

Phosphorylation of intracellular proteins related to the multihormonal regulation of prolactin: comparison of normal anterior pituitary cells in culture with the tumor-derived GH cell lines.

We have previously identified a group of cytoplasmic phosphoproteins (proteins 1-11) whose phosphorylation could be related, on a pharmacological basis, to the multihormonal regulation of PRL synthesis and release in the anterior pituitary tumor-derived GH cell lines. Phosphoproteins with identical migration properties on two-dimensional electrophoresis gels were also detectable in normal rat anterior pituitary cells in culture. We designed appropriate culture and [32P] phosphate-labeling conditions allowing to analyze the regulation of the phosphorylation of these proteins in normal pituitary cells. TRH, 12-O-tetradecanoylphorbol-13-acetate, and vasoactive intestinal peptide induced the same qualitative changes in phosphorylation of proteins 1-11 in normal as in GH cells. Quantitative differences observed are most likely due to the heterogeneity of primary pituitary cultures. Phosphorylation changes affecting proteins 14-16, not previously detected in GH cells, were also observed with normal anterior pituitary cells. GH cell lines have lost the sensitivity of pituitary lactotrophs for dopamine, an important physiological inhibitor of PRL synthesis and release. In normal anterior pituitary cells in culture, dopamine inhibited also the TRH-stimulated phosphorylation of proteins 1-10, thus strengthening the correlation between phosphorylation of these proteins and multihormonal regulation of pituitary cell functions. Our results indicate: 1) that the same phosphoproteins as in GH cells are related to the multihormonal regulation of nontumoral, normal anterior pituitary cells in culture; 2) that dopamine acts by interfering with the phosphorylation of these proteins. The phosphoproteins described here are therefore likely to be part, in normal anterior pituitary cells and possibly in other cell types, of the intracellular machinery involved in the cascade of transducing events leading from the binding of extracellular signals to the regulation of their target biological functions.

Animals↗
PubMed1988

[Myocardial revascularization using both internal mammary arteries. Clinical results and surgical strategy].

To improve the benefits from coronary artery grafting with internal mammary artery (IMA) several technical manoeuvres and methods have been developed to increase the number of coronary arteries and their branches that can be bypassed with internal mammary arteries. Between November 1985 and December 1986, 50 patients underwent a surgical myocardial revascularization procedure using both internal mammary arteries by single or sequential anastomoses and supplemental saphenous vein graft. In 42% of these patients complete revascularization was achieved employing only internal mammary artery grafts. One hundred and twenty-six internal mammary artery grafts (77% of the total coronary bypass performed), were placed. One patient developed perioperative myocardial infarction. Reparative surgery to control immediate post-operative bleeding was required in two patients. Post-operative coronary angiography performed in 30 patients showed all patent internal mammary artery grafts but one. No late deaths occurred. Mean follow-up of 10 months was complete in 50 patients, of whom 94% are symptom free. We conclude that bilateral internal mammary artery grafting can be performed with low operative risk and can provide excellent long-term functional improvement and survival employing only high patency arterial conduit. Moreover, it doesn't significantly increase surgical morbidity.

Adult↗
PubMed1987

[Coronary endarterectomy (blind and open) associated with bypass. Experience in 143 patients].

From June 1982 until January 1986, 173 coronary endarterectomies (EA) with bypass were performed in 143 patients. The series includes 130 conventional EA and 43 open EA with coronary reconstruction. In 9 cases of open EA the revascularization of the reconstructed coronaries was accomplished with internal mammary artery (AMI). 70 (40.4%) EA were performed on the right coronary artery, 75 (43.3%) on the left anterior descending coronary artery and 28 (20.1%) on the left circumflex coronary artery. The early mortality rate in the entire group was 3.5% (respectively 2.0% for the conventional EA and 7.3% for the open EA) and the rate of perioperative myocardial infarction was 8.4% (7.8% in patients receiving conventional EA and 9.7% in those receiving open EA). With mean follow-up of 18.4 months, most (89.8%) of the surviving patients were either symptoms-free or greatly improved. Coronary endarterectomy is a worth-while procedure and it allows surgical management of otherwise inoperables arteries.

Adult↗
PubMed1986

[Phosphorylation of cytoplasmic proteins related to the multihormonal regulation of anterior pituitary cells].

Thyrotropin releasing hormone (TRH) stimulates the synthesis and release of prolactin in mammotropic cells of the anterior pituitary and in GH4C1 cells. TRH simultaneously enhances the phosphorylation of a small number of proteins revealed in GH4C1 cells by two dimensional gel electrophoresis. The same phosphoproteins could be detected in normal rat pituitary cells in primary culture and were phosphorylated with the same pharmacology as in GH4C1 cells. Moreover, these proteins may also be related to hormonal regulations of the other cell types of the anterior pituitary.

Cell Line↗