cis-regulatory elements and trans-acting factors directing basal and cAMP-stimulated human renin gene expression in chorionic cells

Much knowledge was accumulated in the regulation of plasma renin activity and renin secretion during recent years. However, the mechanisms of renin gene transcription, especially for the human gene, have been poorly studied because of the lack of cell lines expressing renin. Cells derived from chorion tissue were used to study renin gene transcription because these cells express renin and regulate renin secretion in a similar way to JG cells. The present study was performed to determine the cis-regulatory elements and the trans-acting factors involved in human renin gene expression using chorionic cells. Transient DNA transfections were performed with various constructs containing the 5'-flanking region of the human renin gene. 5'-Deletion analysis of the human renin promoter (from -2616 to -67 bp) revealed the presence of two proximal negative cis-regulatory elements between -374 and -273 bp and between -273 and -137 bp. These elements were not present in a non-renin-producing cell line, JEG-3 cells. DNase I footprinting revealed that two sequences located within these regions bind trans-factors present in chorionic cellular nuclear extract: AGE3-like sequence (-293/-273) and apolipoprotein A1 regulatory protein-1-like sequence (-259/-245). The first 110 bp of the renin promoter were sufficient to direct specific expression in chorionic cells and contained two footprints sharing homology with ets (-29/-6) and pituitary-specific factor (Pit-1) (-70/-62) sequences. Furthermore, one footprint (-234/-214) contained the sequence TAGCGTCA, which shares strong homology to the cAMP-responsive element (CRE) binding site. Gel shift analysis showed specific DNA/protein complexes within this region, which were displaced by the somatostatin consensus CRE. Finally, luciferase analysis of 5'-deletion mutant revealed that -273 to +16 bp of the renin promoter was sufficient to confer complete forskolin stimulation, whereas deletion to -130 (deletion of the CRE) decreased cAMP responsiveness by 50% and those to -67 bp (deletion of the CRE and Pit-1-like sequences) suppressed it. Thus, these latter two sequences probably act together to confer complete cAMP responsiveness.

Expression of PC2 and PC1/PC3 in human pheochromocytomas

Expressions of two Kex2-related proteases, Pc2 and PC1/PC3, and of one of their possible substrates, proenkephalin, were examined in normal (n = 7) and various pathological (n = 48) human adrenal tissues. Northern blot analysis detected the expression of these genes in pheochromocytomas only. In the 20 pheochromocytomas studied with this technique, PC2, PC1/PC3 and proenkephalin were expressed in 85%, 50% and 90%, respectively. The presence of PC2 and PC1/PC3 was further confirmed using the sensitive RT/PCR techniques. Other evidence of human tumoral adrenal medullary PC2 expression was provided by in situ hybridization and immunohistochemistry. In addition, proenkephalin was expressed only in the pheochromocytomas expressing PC2 and/or PC1/PC3. These results demonstrate that functional Kex2-related endoproteases are expressed in human pheochromocytomas and may be involved in the processing of proenkephalin.

Co-expression of PC2 and proenkephalin in human tumoral adrenal medullary tissues

Expression of PC2, a Kex2-related protease, and of one of its possible substrates, proenkephalin, was examined in normal adrenal glands (n = 7) and pheochromocytomas (n = 20). PC2 could only be detected in normal adrenal glands using the sensitive RT/PCR technique. By Northern blot, PC2 and proenkephalin were expressed in 85% and 90% of the 20 pheochromocytomas studied, respectively. Moreover, in situ hybridization and immunohistochemistry confirmed expression of PC2 in human tumoral adrenal medullary tissue. These results show for the first time expression of PC2 in human pheochromocytomas which may be involved in the processing of proenkephalin.

Renin mRNA quantification using polymerase chain reaction in cultured juxtaglomerular cells. Short-term effects of cAMP on renin mRNA and secretion

The aim of the present study was to set up a method to quantify renin mRNA levels in mouse renal juxtaglomerular cells, the main physiological site of renin synthesis. Because of the scarcity of the cells, a quantitative polymerase chain reaction had to be developed to measure renin mRNA. Juxtaglomerular cells were isolated and cultured for 2 days under various conditions, and renin mRNA was measured directly from the cytoplasm of the cultured cells without prior RNA purification. An internal standard consisting of a mutated renin mRNA with an insertion of 60 bp was designed to quantify the reaction, ensuring an identical detection and amplification efficiency to the target RNA. Renin mRNA could be precisely quantified between 0.6 and 20 pg, thus allowing its detection in approximately 5000 juxtaglomerular cells. Forskolin, an activator of adenylate cyclase, led to a concentration-dependent maximal threefold increase in renin mRNA in the cultures after 20 hours of incubation. The half-maximal effective dose was 3 x 10(-7) mol/L. The effect of forskolin was mimicked by 10(-5) mol/L isoproterenol, a beta-receptor agonist, and by 10(-5) mol/L isobutylmethylxanthine. A time-course study showed a rapid increase in renin mRNA within 3 hours after forskolin and isoproterenol addition. Renin secretion in the culture medium was measured in parallel and found to be stimulated by both agents. These results show that quantitative polymerase chain reaction is a suitable tool for studying renin gene expression in cultured juxtaglomerular cells. Our findings indicate that cAMP is a potent and fast activator of renin gene transcription and renin secretion in renal juxtaglomerular cells.

Expression of steroidogenic enzyme messenger ribonucleic acids and corticosteroid production in aldosterone-producing and "nonfunctioning" adrenal adenomas

"Nonfunctioning" adrenal adenomas are often diagnosed in patients without recognizable clinical symptoms of adrenocortical hyperfunction. The objective of this study was to determine directly the steroidogenic activity of such adenomas (n = 12) and compare them histologically and functionally to normal human adrenals (n = 6) and aldosterone-producing adenomas (n = 15). The histological appearances of nonfunctioning and aldosterone-producing adenomas were surprisingly similar. Nonfunctioning adrenal adenomas expressed all mRNAs of P450scc, P450c17, P450c21, adrenodoxin, and adrenodoxin reductase with relative levels comparable to those found in normal adrenals. Consistent with their hormone-producing nature, these adenomas had cortisol and aldosterone contents as high as those in normal adrenal tissues, a significantly (P < 0.05) increased 17-hydroxyprogesterone content, and a disproportionally low expression of P450c21 mRNA compared to aldosterone-producing adenomas. Cells isolated from both aldosterone-producing and nonfunctioning adrenal adenomas exhibited highly ACTH-sensitive cortisol and aldosterone production, suggesting again the presence of both zona glomerulosa-like and zona fasciculata-like steroidogenesis in these adenoma tissues. These results indicate that so-called nonfunctioning adrenal adenomas are not without steroidogenic activity. Therefore, the assumption that adrenal adenomas are entirely nonfunctioning in the absence of recognizable hormonal hyperfunction may not be correct.

Regulation of human renin secretion and renin transcription by quantitative PCR in cultured chorionic cells: synergistic effect of cyclic AMP and protein kinase C

A quantitative PCR was developed to measure human renin mRNA in chorionic cells under various stimuli. An internal standard consisting of a mutated renin mRNA with an insertion of 60 bp was designed to quantify the reaction. Quantitative PCR is a suitable tool for studying human renin gene transcription from a low number of cells. Forskolin alone had no effect on either renin mRNA levels or renin production whereas 10(-7)M PMA stimulated renin mRNA levels and renin production 5- and 2.6-fold, respectively, after 24 hours incubation. PMA and forskolin acted synergistically to increase both renin mRNA levels and renin production in a dose-dependent manner.

Detection of renin mRNA in aldosterone-producing adenomas by polymerase chain reaction

1. Ribonucleic acid (RNA) was extracted from two normal human adrenal cortices and from five aldosterone-producing adenomas (APA). 2. The five APA could be categorized, on the basis of in vivo aldosterone responsiveness to angiotensin infusion and upright posture, into two APA responsive to both stimuli, two responsive only to angiotensin infusion, and one unresponsive to either stimulus. 3. RNA was reverse transcribed and coamplified by polymerase chain reaction (PCR) with an internal standard of renin complementary DNA (cDNA) containing a 60 base pair insertion. Renin mRNA in the APA was compared with normal adrenals. 4. Renin mRNA was greater than normal in the two APA responsive to both stimuli and less than, or similar to normal, in the two APA responsive only to angiotensin infusion. Renin mRNA was also less than, or similar to normal, in the APA unresponsive to either stimulus. 5. These findings support a possible role for adrenal renin in the development and biochemical behaviour of angiotensin-responsive APA.

Coexpression of renin, angiotensinogen, and their messenger ribonucleic acids in adrenal tissues

The presence of the two components of the renin-angiotensin system (RAS) has been systematically investigated in human normal and pathological adrenal tissues with two aims: 1) the detection of renin and especially angiotensinogen, which has not been reported before; and 2) to study possible differences in the coexpression of renin and angiotensinogen in tissue of cortical and medullary origin. The relative levels of renin and angiotensinogen mRNAs were determined by Northern blot analysis in normal (n = 5) and pathological adrenal tissues of cortical (n = 23) and medullary (n = 10) origin. Renin, prorenin, and angiotensinogen levels were also measured. Renin concentrations in normal and pathological adrenals were around 30-fold higher than those in the plasma of normal subjects, except for a Cushing's adenoma, which contains an extremely high renin content. Renin accounted for 56% of the total renin in normal adrenals and up to 87% in neoplastic tissues. This high proportion of renin indicates a likely conversion of prorenin to renin within these tissues. Renin mRNA was detected in each group of adrenal tissues. There was a significant correlation between the concentration of renin and its mRNA (r = 0.75; P less than 0.05). Angiotensinogen and its mRNA were detected in all normal and pathological adrenals. Compared to normal adrenal tissues, the relative amount of angiotensinogen mRNA was significantly higher in pheochromocytomas. However, the increased mRNA level in these tissues was not accompanied by a parallel increase in tissue angiotensinogen levels. Since the translational efficiency of angiotensinogen was verified by in vitro cell-free translation, the low level of angiotensinogen compared to the relatively high amount of its mRNA suggests a lack of storage of this protein in adrenal cells, as in liver cells. This study demonstrates that renin and angiotensinogen are coexpressed in normal and pathological tissues. Tissues of different cellular origin (zona glomerulosa, fasciculata, and medullary tissue), were able to express, store, and process renin and synthesize angiotensinogen. There was no obvious relationship between the expression of these proteins and the pathophysiology of the adrenal gland.

Calmodulin antagonists stimulate renin secretion and inhibit renin synthesis in vitro

To find out whether calmodulin activity could be a common denominator for the cellular control of renin secretion and synthesis, we have examined the effects of calmodulin antagonists on the secretion and the synthesis of renin in primary cultures of mouse juxtaglomerular (JG) cells. We found that the calmodulin antagonists calmidazolium (CMDZ), N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7), and trifluoperazine (TFP) strongly stimulated renin release from isolated JG cells with a rank order of potency CMDZ greater than TFP greater than W-7. With the same order of potency as on renin secretion, CMDZ, TFP, and W-7 also inhibited de novo synthesis of renin. This decrease of renin synthesis went in parallel with a general inhibition of protein synthesis in the cultured JG cells. A comparable inhibition of total protein synthesis and renin synthesis as with CMDZ was achieved with cycloheximide. Cycloheximide, however, did not alter renin secretion within 20 h of incubation. Taken together, our findings suggest that inhibition of calmodulin activity exerts a powerful stimulatory effect on the exocytosis of renin in renal JG cells. Calmodulin activity on the other hand is also essentially required for protein and renin synthesis in JG cells. It is not very likely therefore that calmodulin activity positively links renin synthesis and renin secretion in JG cells.

Monoclonal antibodies against a human juxtaglomerular epithelioid granular cell tumour

With the exception of the renin-angiotensin system, the molecular composition of juxtaglomerular epithelioid granular cells (JEG cells) is unknown. We demonstrate the molecular peculiarities of these modified smooth muscle cells using monoclonal antibodies produced against a benign human JEG-cell tumour. Six out of 29 different clones produced antibodies that label JEG cells nearly exclusively. Antibodies from the other clones recognize JEG cells but also granularly or homogeneously distributed antigens of proximal tubule cells. This suggests antigenic similarity between granules of JEG cells and lysosomes of proximal tubule cells. Other clones produce antibodies which tag different cytoplasmic membranes or even mast cells. The antibodies directed exclusively against JEG cells promise to be useful tools to study their physiology and pathology.

Immunocytochemical and biochemical evidence of renin in human lactotrophic cell cultures

Primary cell cultures from human prolactin (PRL)-secreting adenomas were used to test the ability of human lactotrophs to synthesize renin in vitro. The renin content of the culture medium and of cellular extracts was measured by enzyme-linked immunosorbent assay. The level of PRL release in the culture medium and the amount of PRL in a cellular extract were determined by radioimmunoassay. Morphologic studies included indirect immunofluorescence, pre-embedding immunoelectron microscopy using a three-layer peroxidase-antiperoxidase method and postembedding immunoelectron microscopy using protein A-gold complexes. Renin was detected in cellular extracts and was found to be absent in the culture medium, whereas PRL was extracellularly secreted. PRL and renin immunoreactivity was observed in all the cultures studied by immunofluorescence. The subcellular localization of renin was found to be similar to that of PRL and was observed in the rough endoplasmic reticulum, the Golgi apparatus, and cytoplasmic secretory granules. The results suggest that, in vitro, renin may be synthesized and intracellularly metabolized in human adenomatous lactotrophic cells rather than secreted. Cell cultures may be a useful model to further the understanding of the role of a local renin-angiotensin system in PRL secretion.

Renin and cathepsin B in human pituitary lactotroph cells. An ultrastructural study

Renin, prorenin and cathepsin B were localized in human lactotrophs using immunoelectron microscopic techniques. Renin and prorenin were found in numerous cytoplasmic granules. Cathepsin B, a lysosomal enzyme known to be able to activate prorenin into renin, was also present in cytoplasmic granules of lactotrophs. The co-localization of renin and prolactin in the same secretory granules was demonstrated by double immunolabelling. Renin and cathepsin B were co-localized in some granules by the same technique. These results suggest a local activation of renin in the secretory granules of lactotrophs and support the hypothesis of a possible autocrine action of the renin-angiotensin system on prolactin release.

[New imaging technics in dissection of the thoracic aorta]

The multiplicity of imaging for investigation of the thoracic aorta requires that the physician choose a strategy adapted to the disorder involved: this is the case, for example with dissection of the aorta. A critical study of the new methods available which include digital angiography; echocardiography; CT scan; magnetic resonance imaging (MRI), should be compared to "the" reference technique of conventional methods: aortography and two-dimensional cineangiography. In addition, the decision must take into account specific characteristics of the disorder: natural history of the disease and anatomopathological form which are useful for the surgeon in case surgery is decided upon. The strategy proposed remains faithful to two-dimensional cineangiography during the first 72 hours of acute dissection because this disorder is a true surgical emergency at this stage if the ascending aorta is involved. Later, or if the ascending aorta does not appear to be involved, MRI has now proven this efficacy as a first-line diagnostic procedure. The judiciousness of preoperative aortography is still the subject of debate.

Isolation and characterization of renin-producing human chorionic cells in culture

Chorionic tissue is one of the major extrarenal sites of renin production, and as such, cultured chorionic cells are a potential model for in vitro studies of renin biosynthesis and regulation. Human chorionic cells were isolated from four chorions and maintained in tissue culture for a total of eight subcultures. Total renin production was considerable in the primary cultures, but fell gradually with successive passages. The cells could be frozen and thawed without losing their ability to divide or produce renin. Both the primary cultures and the subcultures contained a single type of elongated cell containing abundant rough endoplasmic reticulum and myofibrils, but no renin granules, suggesting that the cells had smooth muscle-like features. Immunocytochemistry indicated that they contained both renin and prorenin. The renin produced by the chorionic 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 biochemical and immunological properties similar to those of pure human renin. The cells contained a renin mRNA that had the same size as that for renal renin (1.6 kilobases), confirming the synthesis of renin by these cells. The cells were also examined for the presence of other components of the renin-angiotensin system. Angiotensinogen and angiotensin I were not detected, but angiotensin-converting enzyme was present in extracts of primary and secondary cultured cells. beta hCG and progesterone were also found in the medium of primary culture. However, the production of beta hCG and progesterone fell after the primary culture, and beta hCG and progesterone were indetectable in secondary and tertiary cultures, respectively. These experiments suggest that these two hormones do not influence renin synthesis or vice versa. Thus, these cultures of human chorionic cells synthesized considerable quantities of prorenin and can provide a permanent source of nonrenal prorenin-producing cells.

[Digital arteriography of the lower limbs by sequential, automatic table translation. Feasibility. Preliminary results]

Digital subtraction angiography (DSA) as a method of evaluating lower limb arteries required examination of one limb at a time up to now. Moreover repeated injections of contrast material were necessary. This problem was mainly due to the relative small image intensifier field available and to the difficulty of repositioning the patient between mask and image acquisition. The authors report the preliminary results obtained with 24 patients studied on angiographic unit equipped with: A DSA system (DG 300-CGR) using 512 X 512 matrix size, an angiographic table (Angix M 200) allowing an automatic sequential translation, a removable image intensifier using a 16 inch field below the table. Thus, all those characteristics allow DSA of lower limb arteries. Only one injection of contrast material (Ioxaglate: 80 ml at 8-10 ml/second) was used per procedure. This, usually, allows good quality examination of lower limb arteries.

Detection and localization of renin messenger RNA in human pathologic tissues using in situ hybridization

In order to investigate the synthesis of renin in human pathologic tissues, the authors used in situ hybridization to detect and localize renin messenger RNA (mRNA). The probe was a 35S-radiolabeled 1.1-kb length complementary DNA of human renal renin. To compare the synthesis with the presence and the storage of renin, renin antigen was assessed by immunohistochemistry in the same tissues. The human pathologic tissues were as follows: two ischemic kidneys related to renovascular hypertension; two renal juxtaglomerular cell tumors; one extrarenal renin-secreting epithelioid sarcoma of soft tissues. In ischemic kidneys, the cells containing both renin mRNA and renin protein were found in numerous juxtaglomerular apparatus and in the wall of arterioles, shown by combined in situ hybridization and immunohistochemistry. Most of the tumor cells in the juxtaglomerular cell tumors and scarce tumor cells in the epithelioid sarcoma of soft tissues were positive by in situ hybridization and immunohistochemistry. These findings demonstrate that the presence of renin in these tissues is associated with local cellular production of renin. In particular, smooth muscle cells of the wall of arterioles are definitely capable of synthesizing renin. Moreover, in these tissues, gene expression (renin synthesis) and renin storage are concordant.

Regulation of prorenin secretion in cultured human transfected juxtaglomerular cells

The regulation of renin secretion was studied in continuous culture of human juxtaglomerular cells (JGC), which provided a permanent source of human renin production (Pinet, F., M. T. Corvol, F. Dench, J. Bourguignon, J. Feunteun, J. Ménard, and P. Corvol, 1985, Proc. Natl. Acad. Sci. USA, 82:8503-8507). 95% of the renin species secreted was prorenin, and therefore this study concerned primarily prorenin secretion. Renin production was stable, since the cells had been maintained in culture for more than two years. In culture, these human cells formed colonies of smooth musclelike cells, and electron microscopy showed the presence of cytoskeleton structures including myofibrils and attachment bodies. This human model was used to investigate the control of prorenin secretion in vitro at cellular level. Various pharmacological agents known to stimulate or inhibit renin secretion were tested in the cell cultures. The variations in prorenin secretion were measured in the supernatant. Forskolin, an independent receptor activator of adenylate cyclase, stimulated prorenin secretion in a dose-dependent manner and this stimulation was mediated by 3',5' cyclic-AMP (cAMP). Angiotensin II (AII) was found to inhibit prorenin secretion directly in a dose-dependent manner and atrial natriuretic factor (ANF), whose effects on human JGC were characterized for the first time, was also shown to exert such inhibition. When the effects of this inhibition by AII and ANF were tested on forskolin-mediated stimulation of prorenin secretion, the latter was inhibited and no change occurred in cAMP release. When JGC were treated with histamine, bradykinin, or one or two bradykinin analogues, the responses suggested that in these cells, H2-histamine receptors and kinin receptors are dependent on adenylate cyclase. One peptide, substance P, had an inhibitory effect on prorenin secretion but it was less important than AII and ANF. The present results demonstrate that the adenylate cyclase system of human JGC remains intact during culture and supports the hypothesis that cAMP is the second messenger and Cai2+, the final messenger involved in renin secretion. The cell system used here permits the evaluation of cellular responses and intracellular events in granulated cells in a human model.

Embolization of the systemic arteries of the lung

Embolization of the systemic arteries of the lung (described by Remy and colleagues in 1973) is now a useful method for the treatment of hemoptysis or hemorrhagic lesions of the lung prior to surgical treatment, or for local treatment of hemoptysis when surgery is contraindicated or unnecessary. The technique is based on the anatomy of the different divisions of the systemic circulation (bronchial and extrabronchial), which for various physiologic reasons may develop hypervascularization. The results, complications, and contraindications of systemic embolization have previously been described and the technique is now commonly practiced.

Renin secretion from malignant pulmonary metastatic tumour cells of vascular origin

1. A pulmonary chemodectoma/glomangiosarcoma that had metastasized from the thigh was studied after removal from a 22 year old Algerian patient with hypertension, high plasma prorenin and signs of secondary aldosteronism. 2. Renin and renin mRNA were localized in sections of the tumour tissue using monoclonal anti-human renin antibody and human renin cDNA probe, respectively. 3. The cells grew prolifically in culture, but, even though their renin content was similar to that of transfected human juxtaglomerular cell tumour cells (approximately 1 pg/microgram DNA), their rate of secretion of renin was much lower (0.05-0.15 cf. 0.5-1.5 pg/h per microgram DNA). 4. Forskolin (10 mumol/l for 24 h) increased secretion of renin from 1.9 +/- 0.36 to 4.1 +/- 0.64 pg/ml per h of culture (P less than 0.001, n = 11), consistent with cAMP being a second messenger in the secretory mechanism. 5. The cells should provide valuable information about intracellular mechanisms for the regulation of renin synthesis and secretion.

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.

[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.

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.

[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.

[Primary tumors of the diaphragm. Apropos of a case]

The diagnosis of diaphragmatic tumours is complicated by their rarity and because they are often difficult to distinguish from the more frequent tumours of surrounding structures. We describe two cases: an invasive fibroma and a primary hydatid cyst. We discuss the differential diagnosis of diaphragmatic tumours and suggest a systematic approach to their radiological diagnosis, stressing the value of ultrasonography, CT scanning and diagnostic pneumoperitoneum.

Cine-angiography during percutaneous transluminal angioplasty of the lower limbs

In the treatment with percutaneous transluminal angioplasty of 65 atheromatous stenosis of the lower limbs including 50 iliac and 15 femoro-popliteal lesions, the authors insist on the value of cine-angiography during the dilatation. Cine-angiography increases the security and the velocity of the examination. The anatomic data of this technic are as precise as those obtained with seriography and a special hemodynamic investigation is obtained with the direction of the flow of the contrast medium in the collateral branches and in the main artery. The cost is less expansive than with seriography.

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.

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.

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.

[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.

[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.

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.

[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.

[Broncholithiasis]

Eight cases of broncholithiasis requiring surgical treatment are reported, and diagnostic and therapeutic difficulties of this affection discussed. Clinical symptomatology is not very specific and associates slight or moderate hemoptyses with signs of a febrile pulmonary disorder. Expectoration of a broncholith was not observed in these cases. Radiological images were suggestive by demonstrating hilar and/or peripheral calcifications, often with a parenchymatous opacity in the same region. Fibroscopy is not always conclusive and may even suggest the presence of a tumor. A tuberculous etiology is admitted in France in spite of the absence of bacilli in the sputum. Differential diagnosis from cancer is a real problem, this explaining why two pneumonectomies were performed, in addition to the six lobectomies.

[Value of cineradiography in the study of Budd-Chiari syndrome. Value of various angiographic technics. Apropos of 8 cases]

Eight cases of surgically proven Budd Chiari disease, have been explored pre- operatively by cine-angiography. This procedure is very safe and simple, and allows a dynamic study of the intra- and extra-hepatic pathways. The authors are reviewing the different modalities of radiologic evaluation of Budd-Chiari disease, including inferior vena cava phlebography, opacification of supra-hepatics veins, and coeliac arteriography. They propose a flow sheet in the radiological work-up of these patients.

Post-traumatic-shock lung: postmortem microangiographic and pathologic correlation

In post-traumatic-shock lung, increased pulmonary vascular resistance and pulmonary hypertension are prominent features. The explanation for them was sought by postmortem microangiography of the lungs of 17 patients dying of respiratory failure after trauma. The 10 patients with thoracic injury died earlier (1-8 days). Extravasation of contrast material due to alveolar capillary rupture was present in all but one specimen and occupied 20% of the sampled area. Pulmonary artery thrombi lay proximal to these extravasations. Hypovascular areas due to infection and hemorrhagic alveolitis were found in all patients and involved 40% of the surface area. The small pulmonary arteries were poorly filled and contained many microthrombi. Some patients had hematomas, cavities, and areas of interstitial edema occupying about 5% of the lung area and associated with compressed or occluded vessels. Several mechanisms including pulmonary trauma may be responsible for the antemortem rupture and obstruction of small blood vessels. In the post-traumatic-shock lung, small artery occlusion and compression are associated with pulmonary hemorrhage, infarction, and infection and are important contributors to perfusion abnormalities and respiratory failure.

[Radiological diagrams of the various anatomical forms of mitral incompetency. Report on twenty-nine cases (author's transl)]

The authors compared the radiological findings in 29 cases with the operative or autopsy findings and discuss the criteria at present adopted during standard radiological examination and hemodynamic and angiographic exploration of mitral incompetency to determine the anatomical type. From the radiological findings, one may characterize acute mitral incompetency with a small heart and pulmonary vascular changes from chronic mitral incompetency, the diagnostic criteria of valvular prolapse, ruptures of the chordae tendineae and poor function of the papillary muscles. The authors give a synthesis of their results compared with those in the literature.

[Pulmonary xanthogranulomas (author's transl)]

The authors report on six cases of pulmonary xanthogranuloma. They stress the latent character of these dense, round isolated parenchymatous tumors. The tumors have an homogeneous aspect without calcifications and regional adenopathies. The radio-clinical diagnosis is difficult to assess because the para-clinical examinations are regularly negative. The differential diagnosis is made either clinically, especially with hamartochondroma and peripheral cancer, or histologically according to the predominance of various types of cells, especially with a solitary plasmocytoma, a lymphoma or a sclerosant hemangioma. Histology is the only key to diagnosis. For these reasons, the decision for surgical intervention presents a problem as the patients, often young, present no visible signs and the lesions evolve but very slowly.