Plasma Concentrations of Brain-derived Neurotrophic Factor in Patients Undergoing Minor Surgery: A Randomized Controlled Trial

We measured perioperative plasma concentrations of brain-derived neurotrophic factor (BDNF), a major mediator of synaptic plasticity in the central nervous system, in males, 30-65 years old, undergoing lumbar or cervical discotomy. Patients were randomly allocated to a general anesthetic with propofol induction and maintenance or with thiopental induction and isoflurane maintenance. BDNF plasma concentrations were measured before induction (baseline), 15 min after induction but before start of surgery, at skin closure, in the post-anesthetic care unit, and 24 h postoperatively. Data from 26 patients (13 in each group) were analyzed. At each time point, BDNF plasma concentrations showed large variability. At baseline, concentrations were 631 +/- 337 (mean +/- SD) pg ml(-1) in the propofol group and were 549 +/- 512 pg ml(-1) in the thiopental-isoflurane group (P = 0.31). At 15 min, concentrations significantly decreased in the propofol group (247 +/- 219 pg ml(-1), P = 0.0012 compared with baseline) but remained unchanged in the thiopental-isoflurane group (597 +/- 471 pg ml(-1), P = 0.798 compared with baseline). At skin closure and in the post-anesthetic care unit, concentrations were not different from baseline in both groups. At 24 h, concentrations significantly decreased below baseline in both groups (propofol: 232 +/- 129 pg ml(-1), P = 0.0015; thiopental-isoflurane: 253 +/- 250 pg ml(-1), P = 0.016). In the propofol group, there was a weak but statistically significant positive correlation (R2 = 0.38, P = 0.026) between the duration of surgery and BDNF plasma concentrations at skin closure. These data suggest that in males undergoing elective minor surgery, BDNF plasma concentrations show a specific pattern that is influenced by the anesthetic technique and, possibly, by the duration of surgery.     

Production and Targeting of the Brucella abortus Antigen L7/L12 in Lactococcus lactis: a First Step towards Food-Grade Live Vaccines against Brucellosis

Brucella abortus is a facultative intracellular gram-negative bacterial pathogen that infects humans and animals by entry mainly through the digestive tract. B. abortus causes abortion in pregnant cattle and undulant fever in humans. The immunogenic B. abortus ribosomal protein L7/L12 is a promising candidate antigen for the development of oral live vaccines against brucellosis, using food-grade lactic acid bacteria (LAB) as a carrier. The L7/L12 gene was expressed in Lactococcus lactis, the model LAB, under the nisin-inducible promoter. Using different signals, L7/L12 was produced in cytoplasmic, cell-wall-anchored, and secreted forms. Cytoplasmic production of L7/L12 gave a low yield, estimated at 0.5 mg/liter. Interestingly, a secretable form of this normally cytoplasmic protein via fusion with a signal peptide resulted in increased yield of L7/L12 to 3 mg/liter; secretion efficiency (SE) was 35%. A fusion between the mature moiety of the staphylococcal nuclease (Nuc) and L7/L12 further increased yield to 8 mg/liter. Fusion with a synthetic propeptide (LEISSTCDA) previously described as an enhancer for heterologous protein secretion in L. lactis (Y. Le Loir, A. Gruss, S. D. Ehrlich, and P. Langella, J. Bacteriol. 180:1895-1903, 1998) raised the yield to 8 mg/liter and SE to 50%. A surface-anchored L7/L12 form in L. lactis was obtained by fusing the cell wall anchor of Streptococcus pyogenes M6 protein to the C-terminal end of L7/L12. The fusions described allow the production and targeting of L7/L12 in three different locations in L. lactis. This is the first example of a B. abortus antigen produced in a food-grade bacterium and opens new perspectives for alternative vaccine strategies against brucellosis.     

Development of glial cells cultured from prenatally alcohol treated rat brain: Effect of supplementation of the maternal alcohol diet with a grape extract

The aim of this work was to investigate the effect of supplementation of a maternal alcohol diet with a grape extract on glial cell development. Glial cells were cultured during 4 weeks from cortical brain cells of the new born offspring in DMEM medium supplemented with fetal calf serum. Enzymatic markers of nerve cell development were measured (enolase isoenzymes and glutamine synthetase). Since alcohol consumption produces free radicals the antioxidant system superoxide dismutase was also investigated. Compared to the decrease found in only alcohol treated animals, all parameters except neuron-specific enolase were antagonized and even stimulated after grape extract supplementation. The effect was more important after only 1 month than 3 months of treatment. Also in the total brain an alcohol antagonizing effect and a glutamine synthetase activation were found. Our data demonstrate that addition of a grape extract to the maternal alcohol diet may partially or completely overcome the alcohol induced retardation of glial cell development.     

The Daiokanzoto (TJ-84) Kampo Formulation Reduces Virulence Factor Gene Expression in Porphyromonas gingivalis and Possesses Anti-Inflammatory and Anti-Protease Activities

Kampo formulations used in Japan to treat a wide variety of diseases and to promote health are composed of mixtures of crude extracts from the roots, bark, leaves, and rhizomes of a number of herbs. The present study was aimed at identifying the beneficial biological properties of Daiokanzoto (TJ-84), a Kampo formulation composed of crude extracts of Rhubarb rhizomes and Glycyrrhiza roots, with a view to using it as a potential treatment for periodontal disease. Daiokanzoto dose-dependently inhibited the expression of major Porphyromonas gingivalis virulence factors involved in host colonization and tissue destruction. More specifically, Daiokanzoto reduced the expression of the fimA, hagA, rgpA, and rgpB genes, as determined by quantitative real-time PCR. The U937-3xκB-LUC monocyte cell line transfected with a luciferase reporter gene was used to evaluate the anti-inflammatory properties of Daiokanzoto. Daiokanzoto attenuated the P. gingivalis-mediated activation of the NF-κB signaling pathway. It also reduced the secretion of pro-inflammatory cytokines (IL-6 and CXCL8) by lipopolysaccharide-stimulated oral epithelial cells and gingival fibroblasts. Lastly, Daiokanzoto, dose-dependently inhibited the catalytic activity of matrix metalloproteinases (-1 and -9). In conclusion, the present study provided evidence that Daiokanzoto shows potential for treating and/or preventing periodontal disease. The ability of this Kampo formulation to act on both bacterial pathogens and the host inflammatory response, the two etiological components of periodontal disease, is of high therapeutic interest.     

Elucidation of the mechanism involved in the regulation of protease production by immobilizedMyxococcus xanthus cells

Summary The mechanism involved in the positive effect of immobilization on protease production byMyxococcus xanthus was investigated. The results have shown that this phenomenon was not related to the difficulty encountered by the potential repressors to diffuse through the gel beads. The positive effect of immobilization on protease synthesis is the result of a different physiological state of the cells due to the stress caused by immobilization.     

Streptococcus suis biofilm: regulation,drug-resistance mechanisms,and disinfection strategies

Streptococcus suis (S. suis) is a major swine pathogen and an important zoonotic agent. Like most pathogens, the ability of S. suis to form biofilms plays a significant role in its virulence and drug resistance. A better understanding of the mechanisms involved in biofilm formation by S. suis as well as of the methods to efficiently remove and kill biofilm-embedded bacteria can be of high interest for the prevention and treatment of S. suis infections. The aim of this literature review is to update our current knowledge of S. suis biofilm formation, regulatory mechanisms, drug-resistance mechanisms, and disinfection strategies.

     

Melittin-induced leakage from phosphatidylcholine vesicles is modulated by cholesterol: a property used for membrane targeting

Melittin, an amphiphathic peptide, affects the permeability of vesicles. This can be demonstrated using the dye release technique. Calcein, a fluorescent marker, is trapped in large unilamellar 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC) vesicles and melittin-induced leakage of the dye can be monitored directly by increasing fluorescence intensity. First, we characterized the effect of increasing cholesterol content in the membrane on melittin-induced leakage and our results reveal that cholesterol inhibits the lytic activity of the peptide. Using intrinsic fluorescence of the single tryptophan of melittin and ²H-NMR of headgroup deuterated phosphatidylcholine, we demonstrated that the affinity of melittin for phosphatidylcholine vesicles is reduced in the presence of cholesterol; this is associated with the tighter lipid packing of the cholesterol-containing bilayer. This reduced binding is responsible for the reduced melittin-induced leakage from cholesterol-containing membranes. The pathway of release was determined to be an all-or-none mechanism. Finally, we investigated the possibility of achieving specific membrane targeting with melittin, when vesicles of different lipid composition are simultaneously present. Melittin incubated together with vesicles made of pure POPC and POPC containing 30(mol)% cholesterol can empty nearly all the cholesterol-free vesicles while the cholesterol-containing vesicles remain almost intact. Owing to the preferential interaction of melittin with the pure POPC vesicles, we were able to achieve controlled release of encapsulated material from a specific vesicle population. Received: 8 May 1996 / Accepted: 12 September 1996