Polyhydroxyalkanoates (PHAs) are a class of polyesters biosynthesized by microorganisms (esp. Ralstonia eutropha) under an unbalanced growth condition, and which are supposed to partly take the place of traditional plastics made from petroleum in the near future since they are harmless to the environment and biodegradable. Organic acids (mainly butyrate, lactate, propionate and acetate) produced from anaerobic digested food wastes, industrial wastes and sewage may be used as cheap carbon sources since the large amounts of the above wastes disposed by industry and family each year. In order to better understand the process of PHAs formation with acids as carbon sources, so as to increase the yields of PHAs. Biosynthesis of PHAs by R. eutropha during the dual nutrient-limitation-zone was investigated with mixed organic acids (the mass ratio of the four component acids was butyrate: propionate: acetate: lactate = 3: 3: 1: 1, which was simulated as once the result of anaerobic digestion of food wastes) as carbon sources and (NH4)2 SO4 as nitrogen source. Two different manners of maintaining the dual-nutrient-limitation zone were adopted by feeding mixed acids and (NH4 )2SO4 at determined rates to the fermentation culture which were free of carbon sources (manner A) or nitrogen sources (manner B) firstly. The results suggest that, first of all, the meaning of the limitation of mixed acids or (NH4)2 SO4 does not mean to limit the supply of them, but mean to feed as more as possible of carbon and nitrogen sources in order to meet the cell growth and PHAs formation of R. eutropha by the largest extent. However, it's indispensable to make the residual concentration of carbon and nitrogen sources as low as possible since organic acids are inhibitive to the cell growth, and most importantly, only under the presence of nitrogen during the PHAS formation period of the fermentation could R. eutropha produce more PHAs than any other unbalanced growth condition. Secondly, with the increase of the width of the dual-nutrient-limitation zone, the yield of PHAs would also increase, it suggest that most of the PHAs were biosynthesized during the dual-nutrient-limitation zone. Finally, in contrast with the dual-nutrient-limitation manner of limiting the nitrogen source at first (manner B), the dual-nutrient-limitation manner of limiting the carbon source at first (manner A) was more favorable for the production of PHAs, and the maximum production of PHAs of these two manners are 3.72 g/L and 2.55 g/L, respectively. It may be because that PHAs formation required enzymes could not be well developed when R. eutropha grow under the state of nitrogen limitation from the beginning of fermentation. Besides, yield of PHAs produced by the dual-nutrient-limitation fermentation is larger than that of the single-nutrient-limitation batch culture. Therefore, it seems that to increase the output of PHAs production, the strategy of maintaining as wide as possible the width of dual-nutrient (C, N)-limitation zone may be effective.
Acetates ; metabolism ; Butyrates ; metabolism ; Cupriavidus necator ; metabolism ; Fermentation ; physiology ; Lactates ; metabolism ; Polyhydroxyalkanoates ; biosynthesis ; Propionates ; metabolism

The isolated dog brain was perfused for a period of 4 minutes with blood normal in all constituents, but pathologically low in oxygen in order to follow the metabolic response of the brain to anoxia. During anoxic perfusion, the brain appears to subsist on the free amino acids in the brain and on glucose taken up from the perfusion blood. Oxygen uptake is relatively constant increasing temporarily immediately after anoxia. The lactic acid formed within the brain during anoxia is not released in any quantity; instead it appears to be metabolized in the brain following the period of anoxia causing a lower than norma1 uptake of glucose. Brain ATP and GrP levels decrease significantly, but not markedly indicating that the brain's energy requirements are being partially met during anoxic perfusion.
Amino Acids/*metabolism ; Animals ; Anoxia/*metabolism ; Brain/*metabolism ; Dogs ; Electroencephalography ; Glucose/*metabolism ; Lactates/*metabolism ; Oxygen Consumption

The hemodynamic and metabolic changes during induced hypotension with isoflurane (isoflurane group) or sodium nitroprusside (SNP group) were observed in twelve mongrel dogs. These hypotensive effects were evaluated at 30 and 60 minutes after the mean arterial blood pressure was lowered to 50% from the control. Hemodynamic changes were evaluated by measuring systemic arterial blood pressure, heart rate, central venous pressure, pulmonary capillary wedge pressure, cardiac output, systemic vascular resistance and pulmonary vascular resistance. Metabolic changes were evaluated by measuring serum lactate and pyruvate, arterio-venous oxygen content difference and oxygen extraction rate. We also compared the ventilatory effect of hypotensive anesthesia by blood gas analysis. The results were as follows: 1. Isoflurane inhalation 2-4% or SNP infusion 10-20 micrograms/kg/min was required to reduce the mean arterial pressure to 50% of the control. 2. Heart rate was decreased slightly in the isoflurane group but significantly decreased in the SNP group. 3. There were no significant changes in central venous pressure and pulmonary capillary wedge pressure in either group. 4. Cardiac output was reduced in both groups but was more severe in the isoflurane group. 5. Systemic vascular resistance was decreased by 36% in the isoflurane group and 47% in the SNP group. 6. Acidosis was apparent and did not recover to the control until 30 minutes after recovery in the SNP group. 7. Arterio-venous oxygen difference was increased during hypotension in the isoflurane group probably due to decreased cardiac output. 8. The lactate/pyruvate ratio increased slightly in the SNP group.
Anesthesia ; Animal ; Dogs ; *Hemodynamics ; *Hypotension, Controlled ; *Isoflurane ; Lactates/metabolism ; *Nitroprusside ; Pyruvates/metabolism ; Pyruvic Acid

OBJECTIVETo explore the effect of Danshensu on the lipid metabolism of hyperlipidemic rats.

METHODSixty clean male SD rats were selected. Twelve of them were selected in the basic control group and fed with common foods, and the remaining rats were fed with the high-fat feeds. After the successful modeling, they were randomly divided into the high-fat control group and low dose (10 mg x kg(-1) x d(-1)), medium dose (20 mg x kg(-1) x d(-1)) and high dose (40 mg x kg(-1) x d(-1)) Danshensu (dissolved in saline) groups. Both of the two groups were abdominally injected with the same volume of normal saline once a day for consecutively 30 days. The serum TG, TC, HDL-C and liver ACC1, FAS, HMGR, CPT-I mRNA expressions were detected.

RESULT AND CONCLUSIONDanshensu could inhibit the LDL-C level, timely clear redundant cholesterol and effectively regulate the lipid metablism of hyperlipidemic rats by reducing the TC content, decrease the fatty acid by reducing the FAS mRNA expression, and reduce the synthesis levels of endogenous cholesterol by inhibit the HMGR mRNA expression.

Animals ; Hyperlipidemias ; drug therapy ; metabolism ; Lactates ; pharmacology ; Lipid Metabolism ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley

To research the pharmacokinetic of Danshensu in brain via microdialysis method and automated blood technique. A microdialysis probe was inserted into the left lateral ventricle, and then dialysate samples and blood samples were continuously collected after iv Danshensu. LC-MS/MS was used to determinate for Danshensu in the dialysate samples. The in vivo recovery was used for the calibration of probe. WinNonlin was used for analyzing all pharmacokinetic data. Pharmacokinetic parameters of DSS in blood and in brain showed that Ke, t1/2,, AUC0-t, MRT were 0.04, 0.018 min(-1), 16.64, 58.76 min, 812.59, 51.19 min x mg x L(-1), 15.28, 79.97 min, respectively. The results were indicated that the study was successfully established LC-MS/MS detection method for Danshensu. Microdialysis combined with automated blood technique could better reflect the dynamic characteristics of Danshensu in the rat brain, and it provides a new perspective for pharmacokinetic study.
Animals ; Brain ; metabolism ; Brain Chemistry ; Lactates ; blood ; pharmacokinetics ; Male ; Microdialysis ; Rats ; Rats, Sprague-Dawley

To identify the metabolites of Danshensu in plasma and urine in rats by using UHPLC-LTQ-Orbitrap method. After oral gavage of Danshensu CMC-Na suspension in SD rats, urine and plasma samples were collected and processed by solid phase extraction. ACQUITY UPLC BEH C₁₈ column (2.1 mm×100 mm, 1.7 μm) was utilized, with 0.1% formic acid (A)-acetonitrile (B) solution as the mobile phase for gradient elution. Negative electrospray ion mode based data-acquisition method was established to collect the mass spectrometry data of biological samples. As a result, Danshensu and 21 Danshensu Ⅰ phase and Ⅱ phase metabolites were finally identified according to the accurate mass measurements, mass fragmentation behaviors and comparing with the reference standards. The main metabolic pathways included dehydration, methylation, glucuronide conjugation, sulfate conjugation and their composite reactions. Consequently, our study expounded metabolites of Danshensu in rats based on UHPLC-LTQ-Orbitrap method and provided a reference for further researches on therapeutic material basis and mechanism of Danshensu.
Animals ; Chromatography, High Pressure Liquid ; Lactates ; blood ; metabolism ; urine ; Mass Spectrometry ; Rats ; Rats, Sprague-Dawley

Ethylglucoside lactate, a novel Alpha-Hydroxy Acids Derivative, was synthesized by transesterification in non-aqueous phase using immobilized lipase as biocatalyst. Based on the studies of the factors effecting initial rate and conversion under atmospheric pressure (solvent, acyl donor, different immobilized lipase, substrate concentration, enzyme concentration and temperature), the results show that solvent-free medium using butyllactate as acyl donor is suitable to the ester synthesis. The reaction conditions have been optimized as the following: the amount of enzyme = 75 g/L, the ethylglucoside concentration = 0.4 mol/L, 70 degrees C, 200 r/min, 50 h, which the conversion was 71%. A 90% conversion and a 60.7 mmol.L-1.h-1 initial rate can be obtained under reduced pressure, which the conditions are enzyme 75 g/L, ethylglucoside 0.35 mol/L, 65 degrees C, 200 r/min and 40 h. The product purified by extraction and SIO2 chromatography was identified by infrared spectroscopy and 1H NMR.
Candida ; enzymology ; Enzymes, Immobilized ; metabolism ; Esters ; metabolism ; Glucosides ; isolation & purification ; metabolism ; Kinetics ; Lactates ; isolation & purification ; metabolism ; Lactic Acid ; metabolism ; Lipase ; metabolism ; Substrate Specificity ; Temperature

To investigate the influence of hyperglycemia on ischemic brain damage, we measured brain ATP, lactate and malondialdehyde (MDA) levels in global cerebral ischemic models of Wistar rats. We induced global cerebral ischemia by the 4-vessel occlusion method. After 30 or 60 min of occlusion, and after 30 min of reperfusion, we measured brain ATP, lactate and MDA levels. During the ischemic period, brain ATP levels decreased to 30-70% of sham groups both in normoglycemic and hyperglycemic groups. But during the reperfusion period, the recovery rate of ATP levels was significantly lower in the hyperglycemic than in the normoglycemic groups (p less than 0.05). After 60 min of global ischemia, brain lactate increased much more in the hyperglycemic than in the normoglycemic group, and, during reperfusion, was washed out slowly in the hyperglycemic group. The MDA level, a parameter of lipid peroxidation, increased more in the hyperglycemic group than in the normoglycemic group during reperfusion periods (p less than 0.05). We conclude that hyperglycemia increases lactate accumulation, delays the recovery of energy metabolism, and enhances the lipid peroxidation in the transient global ischemia of rat brain. These findings may suggest the harmfulness of hyperglycemia in clinical cerebral ischemia.
3,4-Methylenedioxyamphetamine/metabolism ; Adenosine Triphosphate/metabolism ; Animals ; Hyperglycemia/complications/*metabolism ; Ischemic Attack, Transient/complications/*metabolism ; Lactates/metabolism ; *Lipid Peroxidation ; Male ; Rats ; Rats, Wistar

Methoxypoly (ethylene glycol)- block-poly (DL-lactide) (PELA) microcapsules containing bovine hemoglobin (BHb) were prepared by a W/O/W double emulsion-solvent diffusion process. The P50 and Hill coeffcient were 3466 Pa and 2.4 respectively, which were near to the natural bioactivity of bovine hemoglobin. The results suggested that polymer composition had significant influence on encapsulation efficiency and particle size of microcapsules. The encapsulation efficiency could reach 90% and the particle size 3 - 5 microm when the PELA copolymer containing MPEG 2000 block was used. The encapsulation efficiency and particle size increased with the concentration of PELA. Increasing the concentrations of NaCl in outer aqueous solution resulted in the increase of encapsulation efficiency and the decrease of particle size. As the concentration of stabilizer in outer aqueous solution increased in the range of 10 g/L to 20 g/L, the particle size reduced while encapsulation efficiency was increased, further increase of the stabilizer concentration would decrease encapsulation efficiency. Increasing of primary emulsion stirring rate was advantageous to the improvement of encapsulation efficiency though it had little influence on the particle size. The influence of re-emulsion stirring rate was complicated, which was not apparent in the case of large volume of re-emulsion solution. When the wall polymer and primary emulsion stirring rate were fixed, the encapsulation efficiency decreased as the particle size reduced.
Animals ; Biocompatible Materials ; chemistry ; Capsules ; Cattle ; Hemoglobins ; metabolism ; Lactates ; chemistry ; Particle Size ; Polyethylene Glycols ; chemistry ; Technology, Pharmaceutical ; methods

OBJECTIVETo investigate the pharmacokinetics of Danshensu with in vivo microdialysis in freely moving rat's jugular vein.

METHODthree days after a microdialysis probe introducer was implanted into the jugular vein, a microdialysis probe was introduced to the blood vessel, and began to sample following a single intravenous injection (40 mg x kg(-1)) or a single oral dose (40 mg x kg(-1)) of Danshensu. All the samples were analyzed with HPLC. The concentration of Danshensu in blood were calculated according to the recovery of microdialysis probe and the concentration in dialysates. Pharmacokinetic parameters were than calculated with the concentration-time curve.

RESULTFor intravenous administration, t(1/2 zeta) = (69.62 +/- 33.42) min, AUC(0-infinity) = (3416.24 +/- 779.80) min x mg x L(-1), MRT(0-infinity) = (38.15 +/- 8.61) min, and for oral administration, Cmax = (7.42 +/- 3.08) mg x L(-1), tmax = (31.50 +/- 8.57) min, t(1/2 zeta) = (83.25 +/- 37.35) min, AUC(0-infinity) = (793.19 +/- 101.32) min x mg x L(-1), MRT(0-infinity) = (125.89 +/- 58.27) min. The oral bioavailability of Danshensu F = 22.56%.

CONCLUSIONIn vivo microdialysis in freely moving rat's jugular vein is a useful tool to obtain a complete set of free drug concentrations to determine reliable pharmacokinetic parameters.

Animals ; Area Under Curve ; Jugular Veins ; cytology ; metabolism ; Lactates ; pharmacokinetics ; Male ; Microdialysis ; Motor Activity ; Rats ; Rats, Sprague-Dawley