[Visceral artery aneurysms. Multiple aneurysmal localization: a case report and literature review]. / Les anévrismes des artères digestives. A propos d'un cas clinique de localisation anévrismale multiple et revue de la littérature.

Visceral artery aneurysms constitute a rare vascular disease, with a risk of rupture associated to a high mortality. Often asymptomatic, they are discovered following a routine radiological examination. We present the case of a 71-year-old patient with multiple aneurysms involving the celiac trunk, the splenic artery, and the common hepatic artery. The surgical treatment consisted of an aortohepatic bypass using polytetrafluoroethylene prosthesis, after exclusion of all the aneurysms. The angiography and postoperative angioscan demonstrated the perfect patency of the prosthesis, totally excluding the aneurysms. Given the variety of presentations and the absence of precise predictive factors, there is no therapeutic consensus so far. Surgery is the first therapeutic choice. Endovascular treatment by angioembolization must be reserved for particular conditions. The purpose of this article is to propose the best therapeutic approach on the basis of evidence in the literature.

Recurrence of postoperative aortic fistulas: is there an ideal method of prevention? A case report.

There are very few cases in English literature of recurrent postoperative aortic fistulas (RPAFs). These are neo-communications between the aortic bloodstream and the lumen of contiguous organs which occur after unpredictable periods from surgical treatment of a previous fistula. The supradiaphragmatic aorta may fistulize into the airways, pulmonary circulation, oesophagus, and cardiac chambers; the infradiaphragmatic aorta into the intestine, stomach, and vena cava. According to the etiology, aortic fistulas are categorized as postoperative (or secondary) and spontaneous (or primary), and RPAF may be considered a subgroup of secondary fistulas. They may recur even more times in the same patient, hence the role of prevention is of the utmost importance. The simultaneous respect of different surgical principles is crucial to make the risk of recurrence less likely. Surgical treatment represents a real challenge due to the emergency conditions and redo nature of operations. Mortality rate is very high. In this article, we describe a case of recurrent aorto-duodenal communication, we discuss the principles of prevention both for the supra and infradiaphragmatic aorta, we introduce some modifications to the classic categorization and we present the first RPAF literature review.

[Surgery of ventricular tachycardia in post-infarction left ventricular aneurysm]. / Chirurgie des tachycardies ventriculaires sur anévrismes ventriculaires gauches post-infarctus.

The treatment of post-infarction ventricular tachycardias with antiarrhythmic drug therapy, implantable automatic defibrillators, radiofrequency ablation, also includes different surgical procedures such as endocardial resection of the infarct scar, encircling endocardial ventriculotomy and endocardial cryoablation or thermoexclusion by laser. These procedures may be extensive or limited, guided or not by preoperative mapping. The aim of this review of the literature is to update our knowledge of these different surgical techniques and to define their indications.

Internal thoracic arterial grafts evaluation by multislice CT scan: a preliminary study.

BACKGROUND AND AIM: The internal thoracic artery (ITA) has a better long-term patency than saphenous veins, and anastomosis between ITA and the left anterior descending artery (LAD) represents the "gold-standard" of surgical myocardial revascularization. The aim of this study is to evaluate the multidetector multislice CT Scan (MCTS) as a means of postoperative evaluation of ITA coronary artery bypass grafts. METHODS: Twenty-eight patients having been operated on for coronary artery bypass with ITA during a 6-months period, benefited, 7 days after surgery, from a patency and anastomotic site control of ITA with a MCTS associated with cardiac gating (Light Speed, General Electric, USA). RESULTS: Internal thoracic artery bypasses are visualized perfectly on all their courses, with possibility of 3D reconstructions, showing the relationship between cardiac cavities and the arterial bypasses. The anastomotic site on the LAD was, in selected cases, perfectly visualized. Sequential bypasses with left ITA are well visualized as well as T or Y right-to-left ITA grafts. However, surgical clips create some image artefacts. CONCLUSIONS: The postoperative control of ITAs are possible by MCTS with a satisfactory resolution. This makes it possible to check the patency of ITAs, their course on the heart surface, and the location and quality of anastomosis with a noninvasive reproductive method.

Asymmetrically acting lycopene beta-cyclases (CrtLm) from non-photosynthetic bacteria.

Carotenoids have important functions in photosynthesis, nutrition, and protection against oxidative damage. Some natural carotenoids are asymmetrical molecules that are difficult to produce chemically. Biological production of carotenoids using specific enzymes is a potential alternative to extraction from natural sources. Here we report the isolation of lycopene beta-cyclases that selectively cyclize only one end of lycopene or neurosporene. The crtLm genes encoding the asymmetrically acting lycopene beta-cyclases were isolated from non-photosynthetic bacteria that produced monocyclic carotenoids. Co-expression of these crtLm genes with the crtEIB genes from Pantoea stewartii (responsible for lycopene synthesis) resulted in the production of monocyclic gamma-carotene in Escherichia coli. The asymmetric cyclization activity of CrtLm could be inhibited by the lycopene beta-cyclase inhibitor 2-(4-chlorophenylthio)-triethylamine (CPTA). Phylogenetic analysis suggested that bacterial CrtL-type lycopene beta-cyclases might represent an evolutionary link between the common bacterial CrtY-type of lycopene beta-cyclases and plant lycopene beta- and epsilon-cyclases. These lycopene beta-cyclases may be used for efficient production of high-value asymmetrically cyclized carotenoids.

[Cardiac surgery in the octogenarian: what risks for what benefits?]. / La chirurgie cardiaque chez l'octogénaire: quels risques pour quels bénéfices?

About 1 to 8% of patients referred for cardiac surgery in industrialised countries are octogenarians. Hospital mortality is high and depends on age, type of surgery and other predictors of death which are female gender, left congestive heart failure, history of myocardial infarction, chronic obstructive lung disease, renal insufficiency, carotid and others vascular diseases. Morbidity is also very high. Besides supraventricular arrhythmias, respiratory failure is the main cause (20 to 30%) of morbidity, followed by cerebrovascular accident and renal failure. Due to this high rate of postoperative events, the length of stay is significantly increased. At follow-up however, excellent functional status and survival rate is afforded by the operative procedure. The main problem remains the selection of patients in order to improve results.

Biological conversion of cyclic alkanes and cyclic alcohols into dicarboxylic acids: biochemical and molecular basis.

Biological oxidation of cyclic alkanes and cyclic alcohols normally results in formation of the corresponding dicarboxylic acids, which are further metabolized in the cell. The biochemical pathways for oxidative conversion of cyclic compounds are similar in various phylogenetically diverse bacteria. Significant progress has been made in the past 2 years in the isolation and characterization of genes involved in cyclic alkane oxidation pathways in several bacterial species. In this article, we review recent advancements in the field of cyclic alcohol oxidation with focus on the biochemical and genetic characterization of the gene functions. Phylogenetic relationships of the analogous enzymes in the pathways are analyzed. Potential biocatalysis applications of these enzymes are also discussed.

Identification of two gene clusters involved in cyclohexanone oxidation in Brevibacterium epidermidis strain HCU.

Brevibacterium epidermidis HCU can grow on cyclic ketones and alcohols as a sole carbon source. We have previously reported the identification of two cyclohexanone-induced Bayer-Villiger monooxygenase genes by mRNA differential display. Using the related technique of Out-PCR, we have amplified large DNA fragments flanking the two monooxygenase genes. Two large gene clusters were sequenced. Several ORFs in each gene cluster encoded proteins homologous to cyclohexanol and cyclohexanone oxidation enzymes from Acinetobacter. However, the structure of these two gene clusters differs significantly from that of Acinetobacter, where the complete pathway has been described. To assess activity of these genes, they were cloned and expressed in Escherichia coli. In vivo and in vitro assays enabled us to assign functions to the expressed ORFs. These ORFs included a cyclohexanol dehydrogenase, two different epsilon-caprolactone hydrolases and two 6-hydroxyhexanoate dehydrogenases belonging to different enzyme families. Because this environmental isolate is difficult to manipulate, we cannot determine at this time which cluster is involved in the degradation of cyclohexanone under physiological conditions. However, the original differential display experiments and some of the experiments reported here suggest the involvement of both gene clusters in the oxidation of cyclic ketones.

High-density sampling of a bacterial operon using mRNA differential display.

We have implemented a simplified high throughput approach to differential display in order to identify transcriptionally regulated genes in bacteria. In contrast with the few previous applications of differential display to prokaryotes, we use a large number of primers which allows for a high-density sampling of the mRNA population and the identification of many differentially amplified DNA fragments. From the overlap of these short sequences, long contiguous sequences that encode several genes can be assembled. The multiplicity of sampling provides a strong indication that the genes identified are indeed differentially regulated. As a test case, we looked for the genes involved in the degradation of 2,4-dinitrophenol (2,4-DNP) in a Rhodococcus erythropolis strain, HL PM-1. In this experiment a long polycistronic mRNA was sampled repeatedly. The induction of these genes by 2,4-DNP was confirmed by dot blot analysis and two of them were confirmed to be involved in the degradation of 2,4-DNP. This work shows that mRNA differential display is an important tool for the identification of metabolic genes in prokaryotes.

[Results of coronary artery surgery in octogenarians]. / Résultats de la chirurgie coronaire chez l'octogénaire.

Over an 11 year period from January 1990 to December 2000, 3282 patients underwent isolated or combined surgical myocardial revascularisation. In this group, 42 were aged 80 or over (maximum 87 years), 1.3% of the total patient population. The mean age of this subgroup was 81.8 +/- 1.75 years) with a male predominance (61.9%). All patients were autonomous and considered to be in good general and psychological health. Preoperative coronary angiography showed 33.3% of left main stem lesions either alone or associated with a right coronary lesion. The ejection fraction was over 50% in 78.6% of cases. Saphenous vein grafts were used in all but 5 patients who also had left internal mammary artery grafts. Thirteen patients (31%) underwent combined valvular surgery (11 aortic and 2 mitral valve) and 2 patients underwent combined vascular surgery. Three patients were operated as an emergency. A total of 5 patients died in the first 30 postoperative days, a hospital mortality of 11.9%. There were 2 postoperative hemiplegias and 2 cases of renal failure which were aggravated in the postoperative period. The other patients were discharged from hospital with a satisfactory cardiac and functional status. The global mortality was 14% at 3 years and 18% at 5 years. The main bad prognostic factor for survival was the association of aortic valve surgery. In selected octogenarians in good general and psychological health without severe co-morbid conditions, surgical myocardial revascularisation may be considered with an acceptable operative risk.

Late results of double-valve replacement with biologic or mechanical prostheses.

BACKGROUND: We previously showed that the risk of reoperation for structural degeneration of bioprostheses was higher in cases involving patients older than 65 years (p = 0.003) and double-valve replacement (p = 0.02). The purpose of this study was to compare late outcome of mitral-aortic valve replacement using bioprostheses or mechanical valves. METHODS: The bioprosthesis group included all mainland France residents (n = 48) between 55 and 65 years old operated on between 1980 and 1995 for mitral-aortic valve replacement using bioprostheses. The mechanical valve group was obtained by matching each of these patients with a patient operated on using mechanical valves at approximately the same time during the study. RESULTS: In the bioprosthesis group, 10-year survival was 45%+/-8% versus 62%+/-7% in the mechanical valve group (not significant). The linearized reoperation rate was 6.8 per patient-year versus 1.1 per patient-year (p = 0.001), and the linearized reoperative mortality rate was 1.8 per patient-year and 0.7 per patient-year (not significant), respectively. CONCLUSIONS: The reoperative mortality risk after mitral-aortic valve replacement using two bioprostheses does not significantly decrease overall survival after age 65 years.

Simultaneous identification of two cyclohexanone oxidation genes from an environmental Brevibacterium isolate using mRNA differential display.

The technique of mRNA differential display was used to identify simultaneously two metabolic genes involved in the degradation of cyclohexanone in a new halotolerant Brevibacterium environmental isolate. In a strategy based only on the knowledge that cyclohexanone oxidation was inducible in this strain, the mRNA population of cells exposed to cyclohexanone was compared to that of control cells using reverse transcription-PCR reactions primed with a collection of 81 arbitrary oligonucleotides. Three DNA fragments encoding segments of flavin monooxygenases were isolated with this technique, leading to the identification of the genes of two distinct cyclohexanone monooxygenases, the enzymes responsible for the oxidation of cyclohexanone. Each monooxygenase was expressed in Escherichia coli and characterized. This work validates the application of mRNA differential display for the discovery of new microbial metabolic genes.

Management of descending necrotizing mediastinitis: an aggressive treatment for an aggressive disease.

BACKGROUND: Descending necrotizing mediastinitis represent a virulent form of mediastinal infection requiring prompt diagnosis and treatment to reduce the high mortality associated with this disease. Surgical management and a particularly optimal form of mediastinal drainage remain controversial. METHODS: Over a 10-year period, 12 patients were treated at our institution. Surgical treatment consisted of 1 or several cervical drainages, associated with drainage of the mediastinum through a thoracic approach in 11 patients. Thoracic procedures included radical surgical debridement of the mediastinum with complete excision of the tissue necrosis, decortication, and pleural drainage with adequate placement of chest tubes for mediastinopleural irrigation. Transcervical mediastinal drainage was performed in only 1 patient. RESULTS: The outcome was favorable in 10 patients, 9 of whom had mediastinal drainage through thoracotomy. Two patients were initially drained through a minor thoracic approach; the first died of tracheal fistula and the second required new drainage through a thoracotomy. The patient who had transcervical mediastinal drainage without a thoracic approach presented an abscess limited to the anterior and superior mediastinum. In 3 patients, ongoing mediastinal sepsis required a second thoracotomy. CONCLUSION: A stepwise approach with transcervical mediastinal drainage is first justified in patients with very limited disease to the upper mediastinum. However, ongoing mediastinal sepsis requires new drainage, through a major thoracic approach, without delay. Extensive mediastinitis can not be adequately treated without mediastinal drainage including a thoracotomy. This aggressive surgical policy has allowed us to maintain a low mortality rate (16.5%) in a series of 12 patients with this highly lethal disease.

[Extracorporeal circulation for warming in severe accidental hypothermia. 3 cases]. / Circulation extra-corporelle de réchauffement pour hypothermies accidentelles sévères. 3 observations.

BACKGROUND: Severe accidental hypothermia with central temperature below 28 degrees C can result from prolonged cold exposure and lead to a fatal outcome by spontaneous or provoked ventricular fibrillation. CASE REPORT: Three patients were referred for central temperature below 24 degrees C. At admission, the patients had major ventricular rythm disorders (two were in a state of circulatory arrest and the third had auricular fibrillation and circulatory collapse). Emergency care associated internal warning using extracorporeal circulation via the femoro-femoral route with a centrifuge pump. Outcome was favorable in 2 cases. DISCUSSION: Prognosis is very poor in patients who experience severe accidental hypothermia (< 28 degrees C) with circulatory collapse. Death often results from major rhythm disorders. Optimal emergency rewarming and oxygenation using extracorporeal circulatory assistance can be successful.

[Outcome of type I acute aortic dissection operated after 70 years of age. A retrospective study of operated dissection of the aorta in the over 70 years old]. / Devenir des dissections aortiques aiguës de type I opérées après 70 ans. Etude rétrospective des dissections aortiques opérées de plus de 70 ans.

The aim of this study was to assess the perioperative mortality and long-term outcome of Type I dissection of the aorta operated in patients over 70 years age. Of the 87 dissections of the aorta operated between 1988 and 1995, 19 concerned patients aged 71 to 79 (average 74.1 +/- 2.4 years). The procedure was replacement of the ascending aorta with gluing of the false lumen in call ases. Two patients also underwent aortic valve replacement and three also had replacement or repair of the aortic arch. Eleven patients (56%) had circulatory arrests lasting an average of 33 minutes (10-86 minutes). The mortality rate at 30 days was 31.5% (6/19): 3 deaths were due to bleeding, 1 to mesenteric infarction, 1 to cardiac arrhythmia and 1 to a cerebrovascular accident. The morbidity was 53%, mainly due to neurological complications, chest infection and renal failure. After an average period of 36.8 months (range: 3 to 75 months) with no patient lost to follow-up, the late mortality was 23% (3/13), giving actuarial survival rates at 1.5 and 6 years of 63%, 47.5% and 32%, respectively (including the operative mortality). Or the survivors, 9 were in NYHA Classes I-II and 1 in class III. One patient developed a hemiparesis. The authors conclude that, despite high mortality and morbidity at 30 days, long-term survival and its quality are arguments in favour of surgical management, even in elderly patients.

SurA, a periplasmic protein with peptidyl-prolyl isomerase activity, participates in the assembly of outer membrane porins.

Little is known about either the process of periplasmic protein folding or how information concerning the folding state in this compartment is communicated. We present evidence that SurA, a periplasmic protein with peptidyl-prolyl isomerase activity, is involved in the maturation and assembly of LamB. LamB is a trimeric outer membrane porin for maltodextrins as well as the bacteriophage lambda receptor in Escherichia coli. We demonstrate that SurA is involved in the conversion of unfolded monomers into a newly identified intermediate in LamB assembly, which behaves as a folded monomer. The absence of SurA blocks the assembly pathway and leads to accumulation of species prior to the folded monomer. These species also accumulate when the stress sigma factor sigmaE is induced by LamB overexpression. We suggest that accumulation of species prior to the generation of folded monomer is a stress signal sensed by sigmaE.

rpoE, the gene encoding the second heat-shock sigma factor, sigma E, in Escherichia coli.

In Escherichia coli, the heat shock response is under the control of two alternative sigma factors: sigma 32 and sigma E. The sigma 32-regulated response is well understood, whereas little is known about that of sigma E, except that it responds to extracytoplasmic immature outer membrane proteins. To further understand this response, we located the rpoE gene at 55.5' and analyzed the role of sigma E. sigma E is required at high temperature, and controls the transcription of at least 10 genes. Some of these might contribute to the integrity of the cell since delta rpoE cells are more sensitive to SDS plus EDTA and crystal violet. sigma E controls its own transcription from a sigma E-dependent promoter, indicating that rpoE transcription plays a role in the regulation of E sigma E activity. Indeed, under steady-state conditions, the transcription from this promoter mirrors the levels of E sigma E activity in the cell. However, it is unlikely that the rapid increase in E sigma E activity following induction can be accounted for solely by increased transcription of rpoE. Based upon homology arguments, we suggest that a gene encoding a negative regulator of sigma E activity is located immediately downstream of rpoE and may function as the target of the E sigma E inducing signal.

The activity of sigma E, an Escherichia coli heat-inducible sigma-factor, is modulated by expression of outer membrane proteins.

sigma E and sigma 32 are two heat- and ethanol-inducible sigma-factors in Escherichia coli. The sigma 32 regulon is also induced by unfolded and misfolded proteins in the cytoplasm, and the function of many of the proteins in the sigma 32 regulon is to bind to cytoplasmic proteins and assist them in folding or unfolding. To further understand the function of the sigma E regulon, we searched for mutants that affected sigma E activity. Our results indicate that a signal generated by expression of outer membrane proteins modulates sigma E activity. Specifically, sigma E activity is induced by increased expression of OMPs and is reduced by decreased expression of OMPs. In addition, mutations that cause misfolded OMPs induce sigma E activity. This signal is generated after the fate of OMPs and periplasmic proteins diverge in the secretory pathway and is not the result of an accumulation of OMP precursors in the cytoplasm. Our results indicate that this effect of OMPs is specific to the sigma E regulon, because none of the above mutations affect sigma 32 activity. We propose that the sigma E regulon is involved in processes that occur in extracytoplasmic compartments and that these two heat-inducible regulons may have distinct but complementary roles of monitoring the state of proteins in the cytoplasm (sigma 32) and outer membrane (sigma E).