Assessment of usefulness exhibited by different tacks in laparoscopic ventral hernia repair.

BACKGROUND: Laparoscopic ventral hernia repair is becoming a popular technique with good results and fast postoperative recovery. The mesh is placed directly under the peritoneum and anchored with transabdominal sutures and tacks. However, the ideal size of the mesh covering the hernia orifice is know, nor the ideal type or amount of tacks has to be described. METHODS: To assess the forces acting on a single tack, a mathematical model of the ventral hernia was created. The force was described in reference to the surface of the hernia orifice and the pressure in the abdominal cavity. The following different types of mesh were examined in vitro: Proceed (knitted mesh), Dual Mesh (expanded polytetrafluoroethylene [ePTFE] flat mesh), and Shelhigh (biologic flat mesh). The following different tacks also were examined: Protac, Anchor, and EMS. A pig model was used to measure the forces needed to destroy the connection between mesh and tissue and to describe the place of destruction (mesh, tissue, or tack) and the force needed. RESULTS: The force acting on a single tack proportionally depends on the surface of the hernia orifice and the pressure in the abdominal cavity. The force needed to disconnect the tissue and mesh reached 8.97 +/- 0.11 N for ProTac, 2.67 +/- 0.22 N for Anchor, and 6.67 +/- 1.32 N for EMS. These values do not allow the mesh to be held in the right position when the orifice exceeds 10 cm for Protac and EMS. The disconnection of the EMS and Protac junction damages the tissue. Anchor tacks are insufficient to hold the mesh and stay in the tissue CONCLUSIONS: In the case of small hernias (diameter<10 cm) EMS or ProTac used alone are not enough to hold the mesh. Anchor is not recommended alone in any hernia.

Characterization of non-flocculent cells isolated from a culture of flocculent Saccharomyces cerevisiae NCYC 1001.

During cultivation of a flocculent yeast, Saccharomyces cerevisiae 1001, two cell fractions, flocs and free cells, appeared in the medium. Free cells contained cells with a normal ability to flocculate, less flocculent cells and not-flocculent cells. When the non-flocculent cells and not-flocculent cells. When the non-flocculent cell fraction from the postexponential phase of growth was collected and used as an inoculum, the culture showed synchronous growth. The floc forming ability of the yeast cells from this culture increased gradually with the number of divisions.

Purification and characterization of two endo-1,4-beta-xylanases from Antarctic krill, Euphausia superba Dana.

Two Euphausia superba Dana endo-1.4-beta-xylanases (A, and B), hydrolysing xylan in the same manner as the enzyme classified as EC 3.2.1.8, were isolated and purified. (2) The enzymes were distinguished by their molecular mass and charge, affinities towards the oat xylan (Km of 4.1 and 7.7 mg ml(-1), respectively), values of activation energy in oat xylan hydrolysis (35.5 and 42.5 kJ mol(-1), respectively), as well as the way in which they split the substrate. (3) In vitro they showed the same optimal temperature (37-40 degrees C), optimal pH (5.7-6.0), very low thermostability, and were stabilized and activated by Ca2+ and Mg2+ ions, as well as by some unidentified substances with molecular mass less than 17 kDa, present in crude extracts of krill.

Physiological properties and enzymatic activities of Rhizopus oligosporus in solid state fermentations.

The physiology of fungus Rhizopus oligosporus in the solid state fermentation of Pisum sativum was investigated by means of digital analysis of microscopic image. The correlations between the hyphal fractions within physiological zones, the release of glucose and soluble proteins, and enzymatic activities of the examined strain were also estimated.

The application of fungal endoxylanase in bread-making.

The endoxylanase from Aspergillus niger IBT-90 with the specific activity of 21.3 U/mg protein was used for improvement of wheat-rye and whole-meal bread. The addition of this xylanase in the range 500-1000 U/kg flour resulted in improvement of kneading and increase of loaf volume in the case of kinds of bread. This dough supplementation caused better crumb porosity and higher moisture in bread and finally the shelf life is extended. No increase of total acidity was resulted from the enzyme addition. The experimental results have confirmed the applicability of this xylanase in bakery.

Microbial beta-glucanases different from cellulases.

The beta-glucans different from cellulose are the most abundant class of polysaccharides. They are found in microorganisms and higher plants as structural entities of cell wall, as cytoplasmic and vacuolar reserve materials, and as extracellular substances. Enzyme systems capable to hydrolyze beta-glucans are produced by different microorganisms. The occurrence and nature of beta-glucanases and their substrates are reviewed. The regulation of biosynthesis of these enzymes, their properties, substrate and product specificities, mode of action and molecular cloning are described. The participation of beta-glucanases in the morphogenetic events of yeast cell is presented. The role and synergism of different types of 1,3-beta-glucanases in microbial cell wall lysis and the potential application for isolation of intracellular materials like proteins, carbohydrates, enzymes and as an analytical tool are discussed in the light of current knowledge.

Properties of cold-adapted subtilisine-like proteinase of endemic yeast Leucosporidium antarcticum.

An extracellular serine proteinase from psychrophilic marine Antarctic yeast L. antarcticum has been purified to homogeneity and characterized. The enzyme specificity, which resembles both chymotrypsin and subtilisin, as well as kinetic (topt of 25 degrees C, activity up to -20 degrees C, pHoptBzTyrOEt of 8.0-8.5), and thermodynamic properties conferring cold-adaptation of the proteinase, were determined The comparison of N-terminal sequence of 35 amino acid residues with known sequences of serine proteinases indicates that the enzyme can be preliminarly classified as a subtilisin-like proteinase, belonging to the proteinase K subfamily (clan SB, family S8, subfamily C).

Factors affecting the yield and properties of bacterial cellulose.

Acetobacter xylinum E(25) has been applied in our studies in order to find optimal culture conditions for effective bacterial cellulose (BC) production. The strain displays significantly higher stability in BC production under stationary culture conditions. In contrast, intensive agitation and aeration appear to drastically reduce cellulose synthesis since such conditions induced formation of spontaneous cellulose nonproducing mutants (Cel-), which dominated in the culture. Mutation frequency strictly depends on the medium composition in agitated cultures. Enrichment of the standard SH and Yamanaka media with 1% ethanol significantly enhanced BC production in stationary cultures. Horizontal fermentors equipped with rotating discs or rollers were successfully applied in order to improve culture conditions. Relatively slow rotation velocity (4 rpm) and large surface area enabling effective cell attachment are optimal parameters for cellulose production. Physical properties of BC samples synthesized either in stationary cultures or in a horizontal fermentor revealed that cellulose from stationary cultures demonstrated a much higher value of Young's modulus, but a much lower value of water-holding capacity.

Characterization of Staphylococcus aureus strains isolated from cystic fibrosis patients by conventional and molecular typing.

The phenotypic and genotypic characteristics of Staphylococcus aureus strains isolated from respiratory tract of cystic fibrosis (CF) patients were investigated. Slime production, cell-surface hydrophobicity, type of capsular polysaccharide, profile of heteroresistance to methicillin and Sma I restriction profiles were evaluated. S. aureus CF strains have been shown to be heterogeneous in respect to several important features. All of them were slime producing with variation in colony morphology. High or moderate cell-surface hydrophobicity (CSH) was found for, respectively, 16.2% and 83.8% strains. Thirty strains were resistant to methicillin, 60% of them showed heteroresitance and 40% were homoresistant. It was found that 59.6% of strains produced capsular polysaccharides (CP) of 5 or 8 type. Among CP5/CP8 strains, CP8 was the predominant type (81.1%). Typing of 62 CF strains by macrorestriction analysis of chromosomal DNA revealed several major types, differing in their SmaI profiles with a similarity coefficient lower than 0.4. Some of the strains isolated from the same patient at different times of hospitalization, as well as strains isolated at the same time from the relatives, were identical in their PFGE pattern.