Analgesic and physiological effect of electroacupuncture combined with epidural lidocaine in goats.

OBJECTIVE: To investigate physiological and antinociceptive effects of electroacupuncture (EA) with lidocaine epidural nerve block in goats. STUDY DESIGN: Prospective experimental trial. ANIMALS: Forty-eight hybrid male goats weighing 27 ± 2 kg. METHODS: The goats were randomly assigned to six groups: L2.2, epidural lidocaine (2.2 mg kg-1); L4.4, epidural lidocaine (4.4 mg kg-1); EA; EA-L1.1, EA with epidural lidocaine (1.1 mg kg-1); EA-L2.2, EA with epidural lidocaine (2.2 mg kg-1); and EA-L4.4, EA with epidural lidocaine (4.4 mg kg-1). EA was administered for 120 minutes. Epidural lidocaine was administered 25 minutes after EA started. Nociceptive thresholds of flank and thigh regions, abdominal muscle tone, mean arterial pressure (MAP), heart rate (HR), respiratory frequency (fR) and rectal temperature were recorded at 30, 60, 90, 120, 150 and 180 minutes. RESULTS: Lidocaine dose-dependently increased nociceptive thresholds. There were no differences in nociceptive thresholds between L4.4 and EA from 30 to 120 minutes. The threshold in EA-L2.2 was lower than in EA-L4.4 from 30 to 120 minutes, but higher than in EA-L1.1 from 30 to 150 minutes or in L4.4 from 30 to 180 minutes. The abdominal muscle tone in EA-L2.2 was higher at 30 minutes, but lower at 90 and 120 minutes than at 0 minutes. There were no differences in muscle tone between L4.4 and L2.2 or EA-L4.4, and between any two of the three EA-lidocaine groups from 0 to 180 minutes. The fR and HR decreased in L4.4 at 60 and 90 minutes compared with 0 minutes. No differences in fR, HR, MAP and temperature among the groups occurred from 30 to 180 minutes. CONCLUSIONS AND CLINICAL RELEVANCE: EA combined with 2.2 mg kg-1 epidural lidocaine provides better antinociceptive effect than 4.4 mg kg-1 epidural lidocaine alone in goats. EA provided antinociception and allowed a decrease in epidural lidocaine dose.

Consequences of cps mutation of Klebsiella pneumoniae on 1,3-propanediol fermentation.

The filtration in 1,3-propanediol (1,3-PD) downstream process is influenced by the large amounts of capsular polysaccharides (CPS) produced by Klebsiella pneumoniae CGMCC 1.6366. The morphological and fermentation properties were investigated with the CPS-deficient mutant K. pneumoniae CGMCC 1.6366 CPS. Similar biomass was obtained with CGMCC 1.6366, and the mutant strain in batch cultures indicating the cell growth was slightly inhibited by CPS defection. The viscosity of fermentation broth by mutant strain decreased by 27.45%. The flux with ceramic membrane filter was enhanced from 168.12 to 303.6 l h(-1) m(-2), exhibiting the great importance for downstream processing of 1,3-PD fermentation. The products spectrum of mutant isolate changed remarkably regarding to the concentration of fermentation products. The synthesis of important 1,3-PD and 2,3-butanediol was enhanced from 9.73 and 4.06 g l(-1) to 10.37 and 4.77 g l(-1) in batch cultures. The noncapsuled K. pneumoniae provided higher 1,3-PD yield of 0.54 mol mol(-1) than that of encapsuled wild parent in batch cultures. The fed-batch fermentation of mutant strain resulted in 1,3-PD concentration, yield, and productivity of 78.13 g l(-1), 0.53 mol mol(-1), and 1.95 g l(-1) h(-1), respectively.

Metabolism in 1,3-propanediol fed-batch fermentation by a D-lactate deficient mutant of Klebsiella pneumoniae.

Klebsiella pneumoniae HR526, a new isolated 1,3-propanediol (1,3-PD) producer, exhibited great productivity. However, the accumulation of lactate in the late-exponential phase remained an obstacle of 1,3-PD industrial scale production. Hereby, mutants lacking D-lactate pathway were constructed by knocking out the ldhA gene encoding fermentative D-lactate dehydrogenase (LDH) of HR526. The mutant K. pneumoniae LDH526 with the lowest LDH activity was studied in aerobic fed-batch fermentation. In experiments using pure glycerol as feedstock, the 1,3-PD concentrations, conversion, and productivity increased from 95.39 g L(-1), 0.48 and 1.98 g L(-1) h(-1) to 102. 06 g L(-1), 0.52 mol mol(-1) and 2.13 g L(-1) h(-1), respectively. The diol (1,3-PD and 2,3-butanediol) conversion increased from 0.55 mol mol(-1) to a maximum of 0.65 mol mol(-1). Lactate would not accumulate until 1,3-PD exceeded 84 g L(-1), and the final lactate concentration decreased dramatically from more than 40 g L(-1) to <3 g L(-1). Enzymic measurements showed LDH activity decreased by 89-98% during fed-batch fermentation, and other related enzyme activities were not affected. NADH/NAD(+) enhanced more than 50% in the late-exponential phase as the D-lactate pathway was cut off, which might be the main reason for the change of final metabolites concentrations. The ability to utilize crude glycerol from biodiesel process and great genetic stability demonstrated that K. pnemoniae LDH526 was valuable for 1,3-PD industrial production.

Physiologic mechanisms of sequential products synthesis in 1,3-propanediol fed-batch fermentation by Klebsiella pneumoniae.

The glycerol fed-batch fermentation by Klebsiella pneumoniae CGMCC 1.6366 exhibited the sequential synthesis of products, including acetate, 1,3-propanediol (1,3-PD), 2,3-butanediol, ethanol, succinate, and lactate. The dominant flux distribution was shifted from acetate formation to 1,3-PD formation in early- exponential growth phase and then to lactate synthesis in late-exponential growth phase. The underlying physiological mechanism of the above observations has been investigated via the related enzymes, nucleotide, and intermediary metabolites analysis. The carbon flow shift is dictated by the intrinsic physiological state and enzymatic activity regulation. Especially, the internal redox state could serve as a rate-controlling factor for 1,3-PD production. The q(1,3-PD) formation was the combined outcomes of regulations of glycerol dehydratase activity and internal redox balancing. The q(ethanol)/q(acetate) ratios demonstrated the flexible adaptation mechanism of K. pneumoniae preferring ATP generation in early-exponential growth phase. A low PEP to pyruvate ratio corresponded LDH activity increase, leading to lactate accumulation in stationary phase.

Statistical optimization of culture conditions for 1,3-propanediol by Klebsiella pneumoniae AC 15 via central composite design.

A central composite design was used to study the effect of glycerol, rate of stirring, air aeration and pH on the synthesis of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae AC 15. Among the four variables, glycerol and rate of stirring significantly affected 1,3-PD productivity, whereas air aeration and pH were not effective. A quadratic polynomial equation was obtained for 1,3-PD productivity by multiple regression analysis using response surface methodology. The validation experimental confirmed with the predicted model. The optimum combinations for 1,3-PD productivity was glycerol, rate of stirring, air aeration, and pH of 50 g/l, 318 rpm, 0.6 vvm, 6.48, respectively. The subsequent fed batch experiments produced 1,3-PD of 70 g/l at a fermentation of 30 h.