Hydrogenogenic and Sulfidogenic Growth of Thermococcus Archaea on Carbon Monoxide and Formate.

Enrichment and pure cultures of hyperthermophilic archaea capable of anaerobic growth on one- carbon compounds (CO and/or formate) were obtained from deep-sea sites of hydrothermal activity at the Mid-Atlantic Ridge, Lau Basin, and Guaymas Basin. All isolates belonged to the T barophilus-T paralvi- .nellae group within the genus Thermococcus. In all cases available for analysis, the genomes of Thermococcus strains capable of growth by hydrogenogenic utilization of CO and/or formate contained clusters of genes en- coding energy-converting hydrogenase and either CO dehydrogenase or formate dehydrogenase and formate transporter. Apart from the previously known processes of hydrogenogenic oxidation of CO and formate, the oxidation of these substrates coupled to sulfur reduction was observed, processes previously unknown among archaea. The capacities for hydrogenogenic or sulfidogenic oxidation of CO and formate occurred in the studied strains in all possible combinations, which could only in part be explained by peculiarities of organi- zation of genetic determinants revealed in the genomes. Investigation of CO and formate consumption kinet- ics revealed that T barophilus strain Ch5 was able to grow at concentrations close to the environmental ones. Thus, it was shown that hyperthermophilic archaea from deep-sea hydrothermal vents are able to utilize one- carbon substrates of abiotic origin both in the presence of an electron acceptor (sulfur) and in its absence. These processes were probably of importance under the conditions of the early Earth biosphere.

Analysis of three genomes within the thermophilic bacterial species Caldanaerobacter subterraneus with a focus on carbon monoxide dehydrogenase evolution and hydrolase diversity.

BACKGROUND: The Caldanaerobacter subterraneus species includes thermophilic fermentative bacteria able to grow on carbohydrates substrates with acetate and L-alanine as the main products. In this study, comprehensive analysis of three genomes of C. subterraneus subspecies was carried in order to identify genes encoding key metabolic enzymes and to document the genomic basis for the evolution of these organisms. METHODS: Average nucleotide identity and in silico DNA relatedness were estimated for the studied C. subterraneus genomes. Genome synteny was evaluated using R2CAT software. Protein conservation was analyzed using mGenome Subtractor. Horizontal gene transfer was predicted through the GOHTAM pipeline (using tetranucleotide composition) and phylogenetic analyses (by maximum likelihood). Hydrolases were identified through the MEROPS and CAZy platforms. RESULTS: The three genomes of C. subterraneus showed high similarity, although there are substantial differences in their gene composition and organization. Each subspecies possesses a gene cluster encoding a carbon monoxide dehydrogenase (CODH) and an energy converting hydrogenase (ECH). The CODH gene is associated with an operon that resembles the Escherichia coli hydrogenase hyc/hyf operons, a novel genetic context distinct from that found in archetypical hydrogenogenic carboxydotrophs. Apart from the CODH-associated hydrogenase, these bacteria also contain other hydrogenases, encoded by ech and hyd genes. An Mbx ferredoxin:NADP oxidoreductase homolog similar to that originally described in the archaeon Pyrococcus furiosus was uniquely encoded in the C. subterraneus subsp. yonseiensis genome. Compositional analysis demonstrated that some genes of the CODH-ECH and mbx operons present distinct sequence patterns in relation to the majority of the other genes of each genome. Phylogenetic reconstructions of the genes from these operons and those from the ech operon are incongruent to the species tree. Notably, the cooS gene of C. subterraneus subsp. pacificus and its homologs in C. subterraneus subsp. tengcongensis and C. subterraneus subsp. yonseiensis form distinct clades. The strains have diverse hydrolytic enzymes and they appear to be proteolytic and glycolytic. Divergent glycosidases from 14 families, among them amylases, chitinases, alpha-glucosidases, beta-glucosidases, and cellulases, were identified. Each of the three genomes also contains around 100 proteases from 50 subfamilies, as well about ten different esterases. CONCLUSIONS: Genomic information suggests that multiple horizontal gene transfers conferred the adaptation of C. subterraneus subspecies to extreme niches throughout the carbon monoxide utilization and hydrogen production. The variety of hydrolases found in their genomes indicate the versatility of the species in obtaining energy and carbon from diverse substrates, therefore these organisms constitute a remarkable resource of enzymes with biotechnological potential.

Pyrobaculum ferrireducens sp. nov., a hyperthermophilic Fe(III)-, selenate- and arsenate-reducing crenarchaeon isolated from a hot spring.

A novel hyperthermophilic, anaerobic, archaeon was isolated from a terrestrial hot spring at Uzon Caldera, Kronotsky Nature Reserve, Kamchatka, Russia. The isolate, strain 1860(T), grew optimally at 90-95 °C and pH 6.0-7.0. The cells were non-motile straight rods, 1.5-5.0 µm in length, covered with surface-layer lattice. Strain 1860(T) utilized complex proteinaceous compounds as electron donors and ferrihydrite, Fe(III) citrate, nitrate, thiosulfate, selenite, selenate and arsenate as electron acceptors for growth. The sequence of the 16S rRNA gene of strain 1860(T) had 97.9-98.7 % similarity with those of members of the genus Pyrobaculum. On the basis of its physiological properties and phylogenetic analyses including in silico genome to genome hybridization, the isolate is considered to represent a novel species, for which the name Pyrobaculum ferrireducens sp. nov. is proposed. The type strain is 1860(T) ( = DSM 28942(T) = VKM B-2856(T)).

Endovascular treatment of ACom intracranial aneurysms. Report on series of 280 patients.

The immediate and long-term outcomes, complications, recurrences and the need for retreatment were analyzed in a series of 280 consecutive patients with anterior communicating artery aneurysms treated with the endovascular technique. From October 1992 to October 2001 280 patients with 282 anterior communicating artery aneurysms were addressed to our center. For the analysis, the population was divided into two major groups: group 1, comprising 239 (85%) patients with ruptured aneurysms and group 2 comprising of 42 (15%) patients with unruptured aneurysms. In group 1, 185 (77.4%) patients had a good initial pre-treatment Hunt and Hess grade of I-III. Aneurysm size was divided into three categories according to the larger diameter: less than 4 mm, between 4 and 10 mm and larger than 10 mm. The sizes of aneurysms in groups 1 and 2 were identical but a less favorable neck to depth ratio of 0.5 was more frequent in group 2. Endovascular treatment was finally performed in 234 patients in group 1 and 34 patients in group 2. Complete obliteration was more frequently obtained in group 2 unlike a residual neck or opacification of the sac that were more frequently seen in group 1. No peri-treatment complications were recorded in group 2. In group 1 the peri-treatment mortality and overall peri-treatment morbidity were 5.1% and 8.1% respectively. Eight patients (3.4%) in group 1 presented early post treatment rebleeding with a mortality of 88%. The mean time to follow-up was 3.09 years. In group 1, 51 (21.7%) recurrences occurred of which 14 were minor and 37 major. In group 2, eight (23.5%) recurrences occurred, five minor and three major. Two patients (0.8%) presented late rebleeding in group 1. Twenty-seven second endovascular retreatments were performed, 24 (10.2%) in group 1 and three (8.8%) in group 2, seven third endovascular retreatments and two surgical clippings in group 1 only. There was no additional morbidity related to retreatments. Endovascular treatment is an effective method for the treatment of anterior communicating artery aneurysms allowing late rebleeding prevention. Peri-treatment rebleeding warrants caution in anticoagulation management. This is a single center experience and the follow-up period is limited. Patients should be followed-up in the long-term as recurrences may occur and warrant additional treatment.

Isolation of the anaerobic thermoacidophilic crenarchaeote Acidilobus saccharovorans sp. nov. and proposal of Acidilobales ord. nov., including Acidilobaceae fam. nov. and Caldisphaeraceae fam. nov.

An anaerobic acidophilic, hyperthermophilic archaeon, designated strain 345-15(T), was isolated from an acidic hot spring of Kamchatka (Russia). Cells of strain 345-15(T) were regular or irregular cocci, 1-2 mum in diameter, with flagella. Strain 345-15(T) grew optimally at 80-85 degrees C and pH 3.5-4.0 and fermented a wide range of carbohydrates, including polysaccharides. Acetate, ethanol and lactate were the fermentation products. Growth was stimulated by elemental sulfur and thiosulfate, which were reduced to hydrogen sulfide. The G+C content of the DNA was 54.5 mol%. The 16S rRNA gene sequence analysis indicated that strain 345-15(T) belonged to the genus Acidilobus. The level of DNA-DNA hybridization between strain 345-15(T) and Acidilobus aceticus 1904(T) was 61 %. Thus, strain 345-15(T) was considered as representing a novel species of the genus Acidilobus, with the name Acidilobus saccharovorans sp. nov. (type strain, 345-15(T)=DSM 16705(T)=VKM B-2471(T)), which shared the main morphological and physiological properties of the genus but differed by the presence of flagella and the spectrum of substrates utilized. Phylogenetic analysis showed that the genus Acidilobus, with its species Acidilobus aceticus, Acidilobus saccharovorans sp. nov. and 'Acidilobus sulfurireducens', and the genus Caldisphaera, represented by Caldisphaera lagunensis and 'Caldisphaera draconis', formed a separate cluster that adjoins the cluster formed by the species of the order Desulfurococcales. Members of the Acidilobus-Caldisphaera cluster are thermophilic, organotrophic anaerobic cocci that can be distinguished from all species of the order Desulfurococcales on the basis of acidophily. Based on these considerations, we propose a new family, Acidilobaceae fam. nov., to accommodate the subcluster of hyperthermophiles represented by the genus Acidilobus, a new family, Caldisphaeraceae fam. nov., for the subcluster of extreme thermophiles represented by the genus Caldisphaera, and a new order, Acidilobales ord. nov., to accommodate the two new families.

[A survey of the management of unruptured intracranial aneurysms as practised by French neuroradiological and neurosurgical teams]. / Prise en charge des anévrismes intracrâniens non rompus. Enquête de pratique des équipes neurochirurgicales et neuroradiologiques françaises.

BACKGROUND: The lack of consensus in the management of unruptured intracranial aneurysms (UIA) has resulted in a variety of different clinical practices. The aim of this study is to analyze these different practices. METHODS: A questionnaire concerning the management of UIA was mailed out to French neurosurgeons (NS) and neuroradiologists (NR). Eighteen responses from 17 teams of NS and 23 responses from 19 teams of NR were included in our analysis. RESULTS: In making a therapeutic decision, about three-quarters of both NR and NS take into account the age of the patient and all of our responders except one consider the aneurysm's morphology, especially its size and neck structure. Pinpointing the location of the aneurysm is an important factor for 61% of NR and 40% of NS. Information concerning the risk of aneurysm rupture and the risks of treatment is routinely given to the patient orally and, sometimes, in writing. The follow-up of UIA treated by NR usually consists of one X-ray angiography and several MR angiographic (MRA) films taken over a period of at least five years and, sometimes, for the rest of the patient's life (22%). The follow-up after surgical treatment mainly comprises X-ray angiography for a limited period of time-usually from five to ten years. The follow-up of untreated aneurysms is usually by either MRA or angioCT. For most NR, the duration of follow-up is long and, sometimes, unlimited. For NS, the duration is more difficult to pinpoint: the response was indeterminate in 28 and 33% gave no response at all. If the first screening tests negative, 44% of NS and 61% of NR propose a repeat screening. CONCLUSION: Given the differences in the management of UIA as revealed by this survey, a multidisciplinary approach that combines the various clinical practices may be the best way forward.

Phylogenetic systematics of microorganisms inhabiting thermal environments.

Thermal habitats harbor specialized communities of thermophilic microorganisms, primarily prokaryotes. This review considers modern systematics of prokaryotes and the place of thermophilic archaea and bacteria in it. Among the existing hierarchical classifications of prokaryotes, the bulk of attention is given to the one accepted in the current second edition of "Bergey's Manual of Systematic Bacteriology", which is primarily based on 16S rRNA phylogeny and phenotypic properties of the organisms. Analysis of the genomics data shows that they on the whole agree with the 16S rRNA-based system, although revealing the significance of the evolutionary role of lateral transfer, duplication, and loss of genes. According to the classification elaborated in the current edition of "Bergey's Manual", the prokaryotes currently culturable under laboratory conditions are distributed among 26 phyla, two of which belong to the domain Archaea and 24 to the domain Bacteria. Six phyla contain exclusively thermophiles, and eleven phyla contain thermophiles along with mesophiles, thermophiles being usually separated phylogenetically and representing high-level taxa (classes, orders). In light of the data on the topology of the 16S rRNA-based phylogenetic tree and some other data, this review discusses the probable hyperthermophilic nature of the universal common ancestor.

[Risks and responsibilities in diagnostic and interventional radiology. Ethical and medicolegal considerations]. / Risques et responsabilités en radiologie diagnostique et interventionnelle. Aspects éthiques et médico-légaux.

Medical risk management has one main purpose: to ensure the safety of care. The law of March 2002 has generated a true cultural revolution. The radiologist is involved with new and difficult areas of medical liability due to technical advances, the increasing number of imaging techniques, the increasing complexity of imaging techniques, their efficiency and the need for multidisciplinary approach. Imaging recommendations requiring increasing levels of technical and clinical skills. The radiologist is liable with regards to the indications of imaging studies, and also with regards to informed consent. The prevention of medicolegal problems is achieved by competency, which must be combined to good liability insurance and ongoing vigilance supported by appropriate continuous medical education.

Symptomatic Radionecrosis after AVM Stereotactic Radiosurgery. Study of 16 Consecutive Patients.

SUMMARY: The purpose of our study was to analyze the outcome of symptomatic radionecrosis following stereotactic radiosurgery for brain arteriovenous malformations. Of 225 patients treated by linear accelerator radiosurgery for brain AVM, 16 (7,1%) presented post-radiosurgery symptomatic radionecrosis on a mean follow-up period of 50 months (range 1-123 months). Once diagnosed with radionecrosis, 14 of 16 patients were subjected to high dose corticotherapy consisting of escalating doses of dexamethasone for several weeks. The mean interval of occurrence of new symptoms was 11.6 months post-radiosurgery (range 6-20 months). The mean time of follow-up was 2.9 years post radiotherapy ranging from seven months to eight years. Of the 16 patients with symptomatic radionecrosis, 11 (68,75%) showed complete resolution of symptoms while five (31,25%) showed improvement but still presented a neurological deficit at the closing date of the study. At the closing date, 11 patients (68.75%) had angiographically completely obliterated arteriovenous malformations while another two patients had an obliteration of 95% to 98% and one patient had a 98% obliteration with development of a new contralateral AVM. In our series, symptomatic radionecrosis occurred in 7.1% of patients treated with stereotactic radiosurgery for brain AVM. These patients where subjected to a prompt, high dose corticosteroid treatment and most presented symptom resolution or improvement with a fair obliteration rate, offering protection from bleeding. Permanent neurologic deficits attributable to radionecrosis occurred in 2.2% of our patient population treated with stereotactic radiosurgery for brain AVM.

Intracranial aneurysms: clinical value of 3D digital subtraction angiography in the therapeutic decision and endovascular treatment.

PURPOSE: To evaluate three-dimensional (3D) digital subtraction angiography (DSA) as a supplement to two-dimensional (2D) DSA in the endovascular treatment (EVT) of intracranial aneurysms. MATERIALS AND METHODS: In 22 ruptured aneurysms, neck visualization, aneurysm shape, and EVT feasibility were analyzed at 2D DSA (anteroposterior, lateral, and rotational views) and at maximum intensity projection (MIP) and surface shaded display (SSD) 3D DSA. The possibility of obtaining a working view for EVT at 3D DSA and the relevance of measurements in choosing the first coil also were assessed. RESULTS: Two-dimensional DSA images clearly depicted the aneurysm neck in four of 22 aneurysms; MIP images, in 10; and SSD images, in 21, but SSD led to overestimation of the neck size in one aneurysm. Aneurysm shape was precisely demonstrated in five of 22 aneurysms at 2D DSA, in eight at MIP, and in all cases at SSD. In two of 22 aneurysms, EVT seemed to be nonfeasible at 2D DSA; however, SSD demonstrated feasibility and EVT was successfully performed. In one aneurysm, only SSD demonstrated the extension of the neck to a parent vessel, which was proved at surgery. Working views for EVT were deduced from 3D DSA findings in 20 of 21 aneurysms. The choice of the first coil was correct in 19 of 21 aneurysms. CONCLUSION: Three-dimensional DSA is valuable for evaluating the potential for EVT, finding a working view, and performing accurate measurements.

Combined endovascular stenting and endosaccular coiling for the treatment of a wide-necked intracranial vertebral aneurysm. Technical case report.

SUMMARY: We describe a clinical case of the combined application of endovascular stent placement and GDCoils packing in the management of a ruptured wide necked intracranial aneurysm. A 27-year-old man had a subarachnoid haemorrhage secondary to the rupture of a large wide necked left vertebral aneurysm. This aneurysm was judged to be inoperable. A functional occlusion test failed because of poor collateral flow and combined stenting and coiling was used to occlude the aneurysm with preservation of the parent artery. A femoral approach was used. An 18 mm long ACS((R)) Duet stent was placed across the base of aneurysm and expanded to 4 mm to act as a buttress. A microcatheter was then advanced through the stent mesh and GDC's were deposited for occlusion. This technique provides new possibilities for wide-necked intracranial aneurysms. Further studies are required on the mechanical and thrombogenic properties of stents and on the long-term follow-up, but this technology may play a role in some cases of aneurysm treatment.

Pathogenetic and functional characterization of lymphocytes in influenza patients.

The kinetics of acrocentric chromosome associations and chromosome aberrations in peripheral blood and pleural exudate lymphocytes has been studied in 25 influenza patients and 7 exudative pleurisy patients. Lymphocytes without associations and with 2 associated acrocentric chromosomes were activated in the body, since their frequency appeared to be positively correlated with the immunoresponsiveness indices and with clinical symptoms. The number of these lymphocytes in pleural exudate was 2.5 times higher than in the peripheral blood. When comparing the frequency of chromosome aberrations in the patients' lymphocytes to the level of immunity, cytogenetic changes corresponded to the indices of cellular rather than humoral immunity.

Polymorphism of human blood groups and incidence of influenza A/Hong Kong (H3N2).

During three epidemics of influenza A/Hong Kong (H3N2) and experimentally in vaccines, the relation between influenza infection and ABo, Rh and MN blood groups was studied. Examinations of 2760 patients with laboratory-confirmed diagnosis of influenza and 749 persons vaccinated with live influenza vaccine showed that individuals of blood groups O and B were susceptible to influenza 1.67 and 1.20 times more, respectively, than individuals of blood group A. The difference in incidence was most manifested in first attacks and decreased in subsequent epidemics. The increased incidence in individuals of blood groups O and B as compared to those of blood group A was not associated with factors of specific (antibody) and nonspecific (interferon) resistance to influenza but was related to a greater capacity of leukocytes from these individuals to adsorb the virus. No relation between blood groups Ph and MN and incidence of influenza A/Hong Kong (H3N2) was established.