[Comparative analysis of photoselective vaporization of the prostate with the Greenlight laser and open prostatectomy for high volume prostate hypertrophy]. / Analyse comparative coût-efficacité de la photovaporisation prostatique par laser Greenlight et de l'adénomectomie pour hypertrophie de la prostate de gros volume.

PURPOSE: Comparative medical economic study between total prostatectomy and laser in the treatment of benign prostatic hyperplasia in patients whose prostate is more than 80g. MATERIALS AND METHODS: This study compared data registered retrospectively for the group AVH and prospective data for PVP patients. The patients whose prostate weighed more than 80g by echography were selected. The adopted point of view was the one of the hospital and the temporal horizon was of one year after the surgical operation. Direct costs per- and post-surgery were taken into account including specific surgical care and secondary surgical revision. The medical data per- and postoperative were also compared. Primary outcome measure was incremental cost per procedure. RESULTS: Forty-one patients in the AVH group and 53 in the PVP group. The mean length of stay (LOS) is significantly shorter in the PVP group (3.0±1.0 days vs 10.4±4.0; P<0.001). Re-operation rate was significantly lower in the PVP group (1.9% vs 19.5% P<0.001). The cost analysis shows a mean additional cost of 1450 euros for the AVH group. CONCLUSION: PVP was cost-effective because it was more economic and it lead to lower re-operation rate until one year of follow-up than in the AVH group. Nevertheless, these data deserve to be nuanced by unfavorable results of the AVH in comparison with those of the literature.

[Spontaneous spinal epidural haematoma causing rapid flaccid paraplegia in a healthy 25-year-old patient]. / Hématorachis spontané avec paraplégie flasque d'installation rapide chez un patient de 25 ans sans antécédent.

Although clinical presentation of a spinal epidural compressive haematoma is well recognized, causing acute radicular pain shortly followed by cord compression syndrome, its aetiology may pose a quandary. Rare and most commonly seen after trauma, spinal surgery, epidural anaesthesia, anticoagulation therapy, vascular malformation or coagulopathy (haemophilia), spinal epidural haematoma (SHE) can be spontaneous. Surgical decompression remains the mainstay treatment especially when the prognosis depends on the interval to surgery and the severity of preoperative neurological deficit. We report the case of a healthy 25-year-old man who presented, three days after an acute back pain, a flaccid paraplegia with urinary retention. Magnetic resonance imaging of the spinal column identified a compressive SHE extending from T3 to T6, requiring an early laminectomy. After decompression, clinical outcome revealed a complete recovery excepted some mild sensibility trouble remains.

Model of surgical procedures for multimodal image-guided neurosurgery.

OBJECTIVE: Improvement of the planning stage of image-guided surgery requires a better anticipation of the surgical procedure and its anatomical and functional environment. This anticipation should be provided by acquisition of multimodal medical images of the patient and by a better understanding of surgical procedures. In this paper, we propose improvements to the planning and performance of multimodal image-guided neurosurgery through the use of information models related to neurosurgical procedures. MATERIALS AND METHODS: A new generic model of surgical procedures is introduced in the context of multimodal image-guided craniotomies. The basic principle of the model is to break down the surgical procedure into a sequence of steps defining the surgical script. In the model, a step is defined by an action. The model assigns to each surgical step a list of image entities extracted from multimodal preoperative images (i.e., anatomical and/or functional images) which are relevant to the performance of that particular step. A semantic validation of the model was performed by instantiating the model entities for 29 surgical procedures. RESULTS: The resulting generic model is described by a UML class diagram and a textual description. The validation showed the relevance of the model, confirming the main underlying assumptions. It also provided some leads to improve the model. CONCLUSION: While further validation is needed, the initial benefits of this approach can already be outlined. It should add real value to the different levels of image-guided surgery, from preprocessing to planning, as well as during surgery. Models of surgical procedures can manage image data according to the surgical script, which should lead to better anticipation of surgery through the development of simulation tools. Furthermore, the models may improve the performance of surgery using microscope-based neuronavigation systems by making it possible to adapt both visualization and interaction features of multimodal preoperative images according to the model.

Molecular diversity of lactic acid bacteria from cassava sour starch (Colombia).

Lactic acid bacteria and more particularly lactobacilli and Leuconostoc, are widely found in a wide variety of traditional fermented foods of tropical countries, made with cereals, tubers, meat or fish. These products represent a source of bacterial diversity that cannot be accurately analysed using classical phenotypic and biochemical tests. In the present work, the identification and the molecular diversity of lactic acid bacteria isolated from cassava sour starch fermentation were assessed by using a combination of complementary molecular methods: Randomly Amplified Polymorphic DNA fingerprinting (RAPD), plasmid profiling, hybridization using rRNA phylogenetic probes and partial 16S rDNA sequencing. The results revealed a large diversity of bacterial species (Lb. manihotivorans, Lb. plantarum, Lb. casei, Lb. hilgardii, Lb. buchneri, Lb. fermentum, Ln. mesenteroides and Pediococcus sp.). However, the most frequently isolated species were Lb. plantarum and Lb. manihotivorans. The RAPD analysis revealed a large molecular diversity between Lb. manihotivorans or Lb. plantarum strains. These results, observed on a rather limited number of samples, reveal that significant bacterial diversity is generated in traditional cassava sour starch fermentations. We propose that the presence of the amylolytic Lb. manihotivorans strains could have a role in sour starch processing.

Lactobacillus plantarum amylase acting on crude starch granules. Native isoforms and activity changes after limited proteolysis.

The microheterogeneous native amylolytic complex secreted by the isolate A6 of Lactobacillus plantarum revealed a selective enzyme specificity loss when submitted to a limited proteolysis under a suboptimum pH condition. A clear electrophoretic profile change toward just one shorter, more acidic, and equally active polypeptide fragment resulted from the pronase E pretreatment. Although the whole enzyme activity remained apparently unaffected for soluble starch, the native parallel activity on intact and non-gelatinized starch granules either from cereals or tubers was dramatically reduced. This phenomenon was more clearly documented by scanning electron microscopy using the easiest accessible native substrate: wheat starch granules. The anion-exchange-purified native enzymes from L. plantarum displayed a different optimum pH curve when compared with the thermotolerant alpha-amylase from Bacillus licheniformis. The alpha-amylases from the lactic-acid-producing A6 isolate presented an electrophoretic profile easily distinguishable from those from B. liqueniformis and B. subtilis species.

Lactobacillus manihotivorans sp. nov., a new starch-hydrolysing lactic acid bacterium isolated during cassava sour starch fermentation.

Two Lactobacillus strains were isolated from sour cassava starch fermentation. The cells were Gram-positive, catalase-negative, non-spore-forming, non-motile rods. They produced only L(+)lactate and were homofermentative. Growth occurred at pH values of 5.0-7.0 and optimum growth occurred at pH 6.0. Growth was positive at 15 and 45 degrees C. The DNA G + C content was 48.4 +/- 0.2 mol%. Sequence analysis of the 16S rRNA gene revealed that strains OND 32T and YAM 1 clustered with, but were separate from Lactobacillus casei-related taxa. Protein pattern and sequence analyses of the 16S rRNA gene confirmed that the two new isolates represent a new Lactobacillus species, for which the name Lactobacillus manihotivorans is proposed; strain OND 32T is the type strain of this species.

Degradation of Raw Starch by a Wild Amylolytic Strain of Lactobacillus plantarum.

Lactobacillus plantarum A6, isolated from fermented cassava, can break down cassava raw starch that has not been subjected to preliminary physicochemical treatment. When the pH was kept at 6, the microorganism cultured in a bioreactor excreted a high alpha-amylase activity (60 U/ml). Synthesis of the enzyme occurred during the stationary phase and resulted in full hydrolysis of the cassava starch granules. This gave 41 g of lactic acid from 45 g of raw starch after 3 days of fermentation. Enzymatic attack was evident under scanning electron microscopy in the rougher appearance of the surface of starch granules and in the presence of large cavities in some of them. In contrast, when the pH was not regulated, only a small amount of alpha-amylase activity was produced (2 U/ml) and no decrease in the starch content of the medium was observed. However, under scanning electron microscopy, some granules displayed a rougher surface, which might have been the result of weak enzymatic attack.

Production of L-lactic acid by Rhizopus species.

Of 19 Rhizopus spp. only four produced L-lactic acid in shake-flask culture. Aerobically and in the presence of a neutralizing agent, Rhizopus oryzae NRRL 395 produced the highest concentration of L-lactic acid (65 g/l) but with O2-limited growth ethanol was produced instead.

Potential of solid state fermentation for production of ergot alkaloids.

Production of total ergot alkaloids by Claviceps fusiformis in solid state fermentation was 3.9 times higher compared to that in submerged fermentation. Production was equal in the case of Claviceps purpurea but the spectra of alkaloids were advantageous with the use of solid state fermentation. The data establish potential of solid state fermentation which was not explored earlier for production of ergot alkaloids.

Importance of medium pH in solid state fermentation for growth of Schwanniomyces castellii.

Utilization of soluble starch by Schwanniomyces castellii in a solid state fermentation system was highest in unbuffered medium when initial and final pH of the medium were 6.5-7.0 and 4.0-4.6, respectively. An economic strategy involving the use of urea as a sole nitrogen source in medium with initial pH of 6.5 allowed maximum substrate utilization in the absence of buffer and without any contamination in column fermenter.

Heat transfer simulation in solid substrate fermentation.

A mathematical model was developed and tested to simulate the generation and transfer of heat in solid substrate fermentation (SSF). The experimental studies were realized in a 1-L static bioreactor packed with cassava wet meal and inoculated with Aspergillus niger. A simplified pseudohomogeneous monodimensional dynamic model was used for the energy balance. Kinetic equations taking into account biomass formation (logistic), sugar consumption (with maintenance), and carbon dioxide formation were used. Model verification was achieved by comparison of calculated and experimental temperatures. Heat transfer was evaluated by the estimation of Biot and Peclet heat dimensionless numbers 5-10 and 2550-2750, respectively. It was shown that conduction through the fermentation fixed bed was the main heat transfer resistance. This model intends to reach a better understanding of transport phenomena in SSF, a fact which could be used to evaluate various alternatives for temperature control of SSF, i.e., changing air flow rates and increasing water content. Dimensionless numbers could be used as scale-up criteria of large fermentors, since in those ratios are described the operating conditions, geometry, and size of the bioreactor. It could lead to improved solid reactor systems. The model can be used as a basis for automatic control of SSF for the production of valuable metabolites in static fermentors.

[Hydrolysis of cellulose by fungi. 1. Screening of cellulolytic strains]. / Hydrolyse de la cellulose par les moisissures. 1. "Screening" des souches cellulolytiques.

Trichoderma harzianum was selected from 30 strains of cellulolytic fungi with the aim of producing cellulases by solid state fermentation of lignocellulosic substrates. Special attention was paid to cellulase production (i.e. carboxymethylcellulase and filter paper activity), apical growth and conidia production. Under the conditions of our experiments, T. harzianum exhibited the highest cellulasic activities with 1,315 IU/l of carboxymethyl cellulose and 80 IU/l of filter paper activity. Apical growth (1 mm/h) and yield of conidial production (3.25 x 10(10) conidia/g of substrate dry weight) were also valuable characteristics of this strain in the use of solid state fermentation.

[Hydrolysis of cellulose by fungi. II. Production of cellulases by Trichoderma harzianum by fermentation in liquid media]. / Hydrolyse de la cellulose par les moisissures. II. Production de cellulases de Trichoderma harzianum par fermentation en milieu liquide.

Microcristalline cellulose (cellulose Avicel, Merck) supported growth of Trichoderma harzianum and induced production of cellulases in liquid cultures. After 50 h growth, the total cellulasic activities present in both the supernatant and the mycelium were 3,000 IU/l of carboxymethyl cellulose, 400 IU/l of filter paper activity, and 4 IU/l of cotton activity corresponding to 1.7 g/l of proteins. Cellulase production could be increased by a preliminary treatment of cellulose, and pH regulation during growth. The influence of inoculum concentration was studied and an optimum of 3 x 10(7) conidia/g dry weight of substrate was demonstrated. Using a synthetic culture medium, a soluble factor of germination was demonstrated which could be leached out by 3 successive washings of conidia.

[Study of the inhibitory effect of acetylene on the biological methane formation in a paddy soil (author's transl)]. / Etude de l'influence inhibitrice de l'acétylène sur la formation biologique du méthane dans un sol de rizitère

A 0.05 atm partial pressure of acetylene stopped all the CH4 evolution during anaerobic paddy soil incubations when different carbon substances were added. It was shown proof that acetylene did not disturbe the volatil fatty acids yielding but prohibited the methane forming bacteria from doing future use of those. Acetylene does inhibit methane forming bacteria. Besides, the growth of a Methanosarcina strain was stopped by a 0.01 atm partial pressure of acetylene, and resting cells lost 98 per cent of their activity when the acetylene concentration was 0.5 x 10-3 M in the liquid. This acetylene inhibition can be used for studying the metabolism of methane forming bacteria.