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Biomedical subjects

F Pinet

Publications and source records attributed to F Pinet.

At least 55 records · Page 3Linked to original sources
PubMed1986

Role of cyclic AMP in renin secretion by human transfected juxtaglomerular cells.

A human juxtaglomerular (JG) cell tumour was used for immortalization of renin secreting cells with three SV40 mutants. These transformed cells retained the same light and electron microscopic morphology as the human renal JG cells throughout subculture. Immunocytochemical staining showed the presence of renin in the elongated cells containing myofilaments and secretory granules. The renin produced was not stored within the cells but was released rapidly into the medium as prorenin. This permanent source of renin-producing cells was used for the study of renin regulation in vitro. Agents known to induce renin release such as dibutyryl cyclic AMP (cAMP), forskolin, isoproterenol and histamine were tested in cell culture. Forskolin induced renin secretion in a dose-dependent manner, as did dibutyryl cAMP. The JG cells responded to beta-agonists and to histamine by an H2 receptor. These results offer direct support for the hypothesis that cAMP is the second messenger in stimulation of renin secretion from human juxtaglomerular cells.

Bucladesine↗
PubMed1986

[Radiology in renovascular hypertension from i.v. urography to digital subtraction angiography. A critical evaluation].

For the last 20 years, the value of radiology in renovascular hypertension (RVH) is well established from diagnostic and therapeutic points of view. However things are changing now due to a better appraisal of the incidence of RVH, new antihypertensive drugs, and new radiological procedures (digital angiography, percutaneous transluminal angioplasty). The approach now takes in account the mode of imaging for a better evaluation of the renal artery stenosis and costs of the procedures as well. Finally a new strategy has been set up for RVH patients management.

Angiography↗
PubMed1985

Isolation of renin-producing human cells by transfection with three simian virus 40 mutants.

A human juxtaglomerular cell (JGC) tumor was used for the immortalization of renin-secreting cells. The transfection of primary JGC with three different simian virus 40 (SV40) mutants resulted in the continuous production of renin-secreting cells. The most efficient renin-producing cells (producing about 400 pg of renin per 24 hr per ml of culture medium) were those transfected with the PAS SV40 mutant. The renin production was stable and the cell cultures have been maintained for greater than 1 year. Two types of cells were cultured together and could not be separated: round and birefringent cells, which exhibited features of mast cells, and elongated cells containing myofilaments and secretory granules. Immunocytochemical staining showed the presence of renin in this latter cell type. The renin produced by the transfected cells was not stored within the cells but was released rapidly into the medium. More than 95% of the renin produced was prorenin, which, after activation, had characteristics similar to those of pure human standard renin as to its enzymatic, immunologic, and biochemical properties, except that it was less glycosylated. These stable JGC tumoral cell lines provide a unique system for studying human renin biosynthesis and its regulation in vitro.

Antigens, Viral, Tumor↗
PubMed1985

[Contribution of digital venous angiography to the evaluation of arterial hypertension. Cost evaluation].

Concerning 100 intravenous digital subtraction angiographies (IV DSA) performed for the study of arterial hypertension, the results are discussed according to two different achievements: diagnostic and economic. One hundred patients have been examined after the intravenous (IV) injection of contrast material, seventy times in peripheral and thirty times in central venous system. Out of 94 examinations that could be interpreted, 10 revealed stenosis of renal arteries higher than 50 per cent, one revealed fibromuscular dysplasia. IV DSA generally permits the correct study of renal arteries and compared to conventional angiography it gives only a small number of false negative results. However, the reliable study of intrarenal vascularisation can be obtained only by renal arteriography. The renal arteriography remains therefore necessary: when renal IV DSA gives insufficient data; to estimate the degree of stenosis in fibro-muscular dysplasia; to evaluate intrarenal vascularisation before renovascular surgery or angioplasty. To estimate the economic validity of renal IV DSA for the study of arterial hypertension, we have investigated: the actual cost of the examination for a department of radiology, compared with the cost of conventional examination; on the other hand, the influence of this examination on the duration of hospitalisation for evaluation of arterial hypertension. According to our investigation, this examination allows the average reduction of expenses for 180 F per patient with arterial hypertension, and shortens the time of hospitalisation for about one day. Owing to this diagnostic and economic contribution, renal IV DSA is becoming the first examination to be done for the evaluation of renovascular hypertension.

Angiography↗
PubMed1985

[Late post-traumatic hemoptysis caused by hypervascularization in the area of pulmonary hematomas. Apropos of a case].

The authors report a case of hemoptysis occurring after closed chest trauma complicated by spontaneously regressive parenchymatous hematomas. Bronchial arteriography showed systemic hypervascularisation with shunt in the territory of a hematoma which had regressed spontaneously several months previously. The authors mention the rarity of this aetiology and emphasise the value of bronchial arteriography and of embolisation.

Adult↗
PubMed1984

[Pulmonary hamartoma. Apropos of 49 surgically treated cases].

A series of 49 patients with pulmonary hamartoma subjected to operation is described. 28 patients were male and 21 female, with a mean age of 49.8 years. Most cases were discovered on routine chest films. Six patients had radiologic changes produced by obstruction, while 43 had a rounded peripheral opacity. Fine calcifications were present in four cases. In no case was diagnosis achieved by bronchoscopy, whereas one of the more recent cases was diagnosed by percutaneous fine needle biopsy. Sinner has shown that this last technique can establish diagnosis in most cases. As such tumors are invariably benign and grow slowly, diagnosis by percutaneous biopsy renders operation unnecessary: periodic follow up only is required.

Adolescent↗
PubMed1984

[Radiology of spontaneous pneumothorax in young patients. Apropos of 200 cases].

In 200 young patients with apparently idiopathic spontaneous pneumothorax, the following radiologic features were analyzed: degree of collapse on the initial chest film, areas of atelectasis, and presence of blebs, apical opacities, fibrous adhesions, pleural effusions, and controlateral shift of mediastinal structures. Confrontation of apical changes with pathologic findings in operative specimens suggests that mesothelial rupture with reactive hyperplasia results in a "pneumatization chamber" visible as a bullous image. Following drainage, homolateral shifts of mediastinum and four cases of pulmonary edema were recorded. Risk factors for pulmonary edema include severe pulmonary collapse with areas of atelectasis, persisting for more than 48 hours and an aspiration which either exceeded 1.5 l. of air or was performed with a depression of more than 30 cm of water.

Adolescent↗
PubMed1984

Prognostic factors and indications for surgical treatment of acute aortic dissections: a report based on 191 observations.

A total of 191 acute aortic dissections were examined to define prognostic factors for surgical intervention. Overall survival rate reached 40% in the 94 patients operated upon and 8% in the 97 patients not operated upon. Among the 122 patients with involved ascending aorta, survival rate was 2% in the 42 nonoperated patients versus 42% in 80 patients undergoing surgery. Since 1977, overall survival rate has reached 60% in the surgical group (21 of 35 patients) and 20% in the nonsurgical group (5 of 25 patients). Factors that showed a significant correlation with postoperative death include: persistent shock; persistent anuria; persistent neurologic deficit; diffuse intravascular coagulation; and involvement of either the celiac trunk, superior mesenteric artery, or both renal arteries at angiography. With the exception of those patients exhibiting any of these high-risk factors, emergency surgical treatment is recommended for all dissections that involve the ascending aorta.

Adult↗
PubMed1984

Effects of glucocorticoids and antiglucocorticoid on angiotensinogen production by hepatoma cells in culture.

Angiotensinogen is synthesized in large amounts by Fao cells derived from the Reuber H35 rat hepatoma in a medium enriched with 5% fetal bovine serum (FBS). Treatment of FBS with dextran-coated charcoal removed endogenous steroids without modifying angiotensinogen production. This treatment allowed the study of the effects of steroids on angiotensinogen production. Hydrocortisone increased the angiotensinogen synthesis in a dose-dependent manner. The antiglucocorticoid RU 38486 did not change the basal rate of angiotensinogen production but inhibited the stimulation by hydrocortisone. Similar results were obtained with dexamethasone. Angiotensinogen biosynthesis seems to be regulated by two distinct mechanisms: (a) glucocorticoid independent, controlling the basal rate of angiotensinogen production and (b) glucocorticoid dependent, mediating the increased rate of angiotensinogen production upon glucocorticoid treatment.

Angiotensinogen↗
PubMed1984

Characterization of precursor and secreted forms of rat angiotensinogen.

Angiotensinogen precursors synthesized by rabbit reticulocyte lysate primed with rat liver RNA were compared with angiotensinogen secreted by rat hepatoma cells and rat hepatocytes using immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Inhibition of glycosylation with tunicamycin permitted identification of the nonglycosylated form of secreted angiotensinogen. Whereas angiotensinogen secreted by hepatoma cells and hepatocytes showed electrophoretic heterogeneity (mol wt, 52-62 X 10(3], tunicamycin-treated cells secreted only a single angiotensinogen species [mol wt, 48.3 +/- 0.7 X 10(3) (mean +/- SD)], which could be cleaved by renin. Two putative angiotensinogen precursors were synthesized in the reticulocyte lysate: a major protein of 52.5 +/- 1.0 X 10(3) mol wt and a minor protein of 55.7 +/- 1.3 X 10(3) mol wt. Evidence that these proteins represent separate angiotensinogen precursors includes the following. 1) Both proteins were recognized by five different polyclonal antibodies and two monoclonal antibodies. 2) Both proteins increased in parallel in reticulocyte lysates primed with liver RNA from rats nephrectomized and given hormones that increase liver angiotensinogen production. 3) Both proteins were cleaved by renin to produce a single protein of 47.6 +/- 0.8 X 10(3) mol wt. 4) The des-angiotensin I-angiotensinogen generated by renin treatment of the lysate had an electrophoretic mobility identical to that of des-AI-angiotensinogen produced by renin treatment of nonglycosylated angiotensinogen secreted by tunicamycin-treated hepatoma cells and hepatocytes. These studies suggest that rat liver synthesizes two separate angiotensinogen precursors which may differ only in the size of their prepro sequence. The heterogeneity of secreted angiotensinogen can be fully accounted for by differences in N-glycosylation of asparagine residues of the molecule. Glycosylation of angiotensinogen is not essential for its synthesis, processing, and secretion or its hydrolysis by renin.

Angiotensinogen↗
PubMed1984

Angiotensin I-converting enzyme in foetal membranes and chorionic cells in culture.

Angiotensin I-converting enzyme (ACE) is found in human amniotic fluid and foetal membranes taken during Caesarean sections at term. ACE contents are higher in the chorion than in the amnion. Cells cultured from chorion contain ACE together with renin. Chorionic ACE was inhibited by captopril and by an excess of anti-ACE immuneserum. It is concluded that extravascular ACE is present in the uteroplacental complex during pregnancy.

Amniotic Fluid↗
PubMed1983

[Emergency radiology in acute traumatic rupture of the thoracic aorta. Detection of atypical forms. Apropos of 52 cases].

Fifty-two traumatic ruptures of the thoracic aorta were hospitalized between 1972 and 1982, with 46 angiographies. The most significant clinical sign of aortic rupture is the difference in blood pressure between the upper and lower limbs. The frequency of chest film findings is discussed. The aortography by arterial route must be performed at the sligh test suspicion, sometimes without radiographic signs, to establish diagnostics and detect associated lesions (dissection) and unusual types (low localization, multiple localization, localized rupture of the intima.

Accidents, Traffic↗