Plasma D-lactate Research Articles

The protective effects of inhibition of c-Jun N-terminal kinase signal pathway on the intestinal barrier in rats with endotoxemia

To examine the protective effects of inhibition of c-jun N-terminal kinase (JNK) stress signal pathway on the injured barrier in endotoxemic rats. Twenty-four male Sprague Dwaley (SD) rats were randomly divided into control group, endotoxemia model group and JNK inhibitor group (n=8 each) to receive administration of: 1 normal saline 2 ml/kg + PPCES 2.5 ml/kg [vehicle of JNK inhibitor (SP600125), control group]; 2 lipopolysaccharide (LPS) 10 mg/kg + PPCES 2.5 ml/kg (endotoxemia model group); 3 LPS 10 mg/kg + JNK inhibitor (SP600125) 10 mg/kg (JNK inhibitor group). The activity and survival rate of the rats were recorded. Ileum tissue samples were collected 12 hours after drug administration for pathological examination. Blood samples were collected at the same time for determination of concentration of D-lactate by enzyme linked immunosorbent assay (ELISA). Rats in control group were active normally, and there was no death. Pathological examination showed there was edema of ileal mucosa, and shortening of villus and inflammatory cell infiltration in model group as compared with control group. JNK inhibitor greatly ameliorated the lesions compared with model group. The concentration of D-lactate (µg/L) in model group was significantly higher than that in control group. (943.8 ± 439.6 vs 227.9 ± 130.0, P<.05). JNK inhibitor could decrease the plasma D-lactate concentration (637.4 ± 114.4 vs 943.8 ± 439.6, P<.05). Inhibition of the JNK stress signal pathway could attenuate the intestinal barrier injury in endotoxemic rats.

The protective effects of penehyclidine hydrochloride on intestinal mucosa injury in rabbits with traumatic shock model

Objective To investigate the protective effects of penehyclidine hydrochloride(PHC) on intestinal mucosa injury in rabbits with traumatic shock. Methods The animal model of traumatic shock was established according to Lamson's method.Thirty rabbits were divided into five groups randomly:control group (Con group),traumatic shock group resuscitation with normal saline (NS group),traumatic shock group resuscitation with pcnehyclidine hydrochloride in low dosages (0.05 mg/kg,PHCL group),middle dosages group (0.15 mg/kg,PHCM group) and high dosages group (0.45 mg/kg,PHCH group).At pre-shock,postshock,four time points (T3-T(o)) after resuscitation,mean arterial blood pressure(MAP) and heart rate(HR) were monitored.Plasma diamine oxidase (DAO) activity and lactic acid concentration were measured by spectrophotometry at defined time points.At the end of experiment,the animals were sacrificed and the samples were collected.The pathological changes of the samples were observed under microscope. Results There were no significant differences in MAP before shock among the five groups.MAP in NS group,PHCL group,PHCM group and PHCH group decreased post-shock,but there were no significant differences in MAP among groups.At T3-T6 time points,MAP in NS group (68.8±3.0),(67.5±5.3),(71.0±3.7),(71.0±2.4) mm Hg( 1 mm Hg=0.133 kPa),respectively was significantly lower than that before shock (94.3±1.7) mm Hg,also lower than that in the Con group (82.8±4.1),(89.8±6.6),(82A±3.3),(94.4±6.2) mm Hg,respectively and the PHCM gronp (83.2±13.6),(82.2±9.0),(83.8±8.9),(85.4±8.1) mm Hg,respectively.There were no significant differences in HR pre-shock and post-shock among the five groups.At T3-T6 time points,HR in the NS group (185±11),(181±7),(164±13),(164±13) hpm,respectively were signifieandy lower than that at T1(276±13) bpm,also significantly (P＜0.05 or P＜0.01 ) lower than that in the Con group and the PHCM group.The plasma DAO activity and D-lactate concentration in the Ns group,PHCL group,PHCM group,PHCH group were significantly increased at T2-T6 time points.Furthermore,at T3-T6 time poinls,the plasma DAO activity (0,393±0,020),(0.586±0.017),(0.844±0.036),(0.568±0.016) μ/ml,respectively and D-lactate concentration(8.292±0.364),(7.539±0.098),(5.991±0.180),(7,108±0.372) mmol/L,respectively in the NS group were significantly higher than that in the PHCL group and PHCH group; the plasma DAO activity and D-lactate concentration in the PHCL group and PHCH group were significantly higher than in the PHCM group (0.111±0.016),(0.302±0.020),(0.501±0.014),(0.183±0.018)μ/ml; (5.664±0.546),(4.609±0.292),(3.310±0,3634),(4.720±0.205)mmol/L(P＜O.05orP＜0.0l).Intestinal mucosal injury in the PHCM group was significantly reduced compared with tbat in the NS group.Conclusions The resuscitation of PHC combinition with Mnormal saline can stabilize hemodynamics in rabbits with traumatic shock.There was a significant protective effect on intestinal mucosal injury induced by traumatic shock,especially in the PHCM group.The plasma DAO activity and D-lactate concentration can be used to assess the extent of intestinal mucosa injury and barrier function. Key words: Traumatic shock; Penehyclidine hydrochloride; Plasma diamine oxidase; D-lactate; Mean arterial blood pressure

Increased Circulating D-Lactate Levels Predict Risk of Mortality After Hemorrhage and Surgical Trauma in Baboons

Patients with hemorrhagic shock and/or trauma are at risk of developing colonic ischemia associated with bacterial translocation that may lead to multiple organ failure and death. Intestinal ischemia is difficult to diagnose noninvasively. The present retrospective study was designed to determine whether circulating plasma D-lactate is associated with mortality in a clinically relevant two-hit model in baboons. Hemorrhagic shock was induced in anesthetized baboons (n = 24) by controlled bleeding (mean arterial pressure, 40 mmHg), base excess (maximum -5 mmol/L), and time (maximum 3 h). To mimic clinical setting more closely, all animals underwent a surgical trauma after resuscitation including midshaft osteotomy stabilized with reamed femoral interlocking nailing and were followed for 7 days. Hemorrhagic shock/surgical trauma resulted in 66% mortality by day 7. In nonsurvivor (n = 16) hemorrhagic shock/surgical trauma baboons, circulating D-lactate levels were significantly increased (2-fold) at 24 h compared with survivors (n = 8), whereas the early increase during hemorrhage and resuscitation declined during the early postresuscitation phase with no difference between survivors and nonsurvivors. Moreover, D-lactate levels remained elevated in the nonsurvival group until death, whereas it decreased to baseline in survivors. Prediction of death (receiver operating characteristic test) by D-lactate was accurate with an area under the curve (days 1-3 after trauma) of 0.85 (95% confidence interval, 0.72-0.93). The optimal D-lactate cutoff value of 25.34 μg/mL produced sensitivity of 73% to 99% and specificity of 50% to 83%. Our data suggest that elevation of plasma D-lactate after 24 h predicts an increased risk of mortality after hemorrhage and trauma.

Relationship between plasma D-lactate levels and prognosis of neonatal necrotizing enterocolitis

Objective To investigate the relationship between plasma D-lactate levels and prognosis in newborns with neonatal necrotizing enterocolitis (NEC).Methods One hundred and four premature infants with NEC (stase Ⅱ and Ⅲ ) and another 104 premature infants without NEC admitted into Quanzhou Children's Hospital for other diseases from January 2007 to October 2010 were selected into this case control study.The gestational age,gender and birth weight of patients in the two groups were matched.NEC patients' bloods were collected within 24 hours after NEC was confirmed and blood samples of the control group were collected at the corresponding age.Enzymelinked immunosorbent assay was used to detect the plasma D-lactate level.Receiver operating characteristic curve was used to confirm the criteria of D-lactate positive,according to which,the NEC group was divided into high D-lactate group and normal D-lactate group,and the mortality and complication rate of the two groups were compared with x2 test.And NEC group was subdivided into death group and survive group according to the prognosis of the patients,and the difference of D-lactate level between the two groups were compared with t test.Results Among the NEC group,there were 63 cases (60.6％) of stage Ⅱ and 41 (39.4％) cases of stage Ⅲ ; 88 (84.6％) survived infants and 16 (15.4％) dead infants.D-lactate level was (35.4 ± 29.1) μg /ml in stage Ⅲ NEC group,(29.5±16.2) μg/ml in stage Ⅱ NEC group and (3.7±18.4) μg/ml in control group; there were statistical differences between each other(F=5.97,P＜0.05).Receiver operating characteristic curve analysis showed that if 6 μg/ml was set as the borderline,there were 87 cases(83.7％,87/104) with high D-lactate patients in NEC group,whose neonatal critical illness scoring (NCIS) was 80.9±22.6,significantly lower than that of normal D-lactate patients ( 95.8 ± 20.5) (t =2.417,P＜ 0.05),and higher neonatal septicemia rate (48.3％,42/87) and mortality (27.6％,24/87) compared with those [(5.9％,1/17) and (5.9％,1/17)] of normal D-lactate patients(x2 =11.539 and 7.146,P＜0.05,respectively).In NEC group,compared with the survived infants,the D-lactate level [(43.2±13.5) μg/ml vs (21.9 ± 22.9) μg/ml,t =4.572,P＜0.05] and the rate of septicemia [68.8％ (11/16) vs 38.6％ (34/88),x2 =3.445,P＜0.05] were higher in dead patients,and NCIS (82.4± 29.1 vs 90.6 ± 21.3,t =2.409,P＜0.05) was lower.Conctusions The level of plasma D-lactate related to the prognosis of neonatal NEC and which might be a good indicator for its prognosis and severity. Key words: Enterocolitis, necrotizing; Lactic acid; Infant, newborn; Prognosis

A Review of the Predictive Role of Plasma D-Lactate Level in Acute Appendicitis: A Myth or Truth?

Acute appendicitis (AA) is a common condition which warrants emergency surgery. Detailed history, physical exam, and laboratory findings are often nonspecific in suspected patients. There is substantial evidence to indicate that plasma levels of D-lactate were useful to establish a diagnosis of AA in the medical literature. It has been suggested that it is useful for patients with abdominal pain, especially patients with perforated AA. This paper is designed to highlight the value of D-lactate biomarker in establishing a diagnosis of AA. Based on the literature, it is not helpful for a decision of operation in patients with AA. According to the results of the studies, laboratory involvement was observed between plasma D-lactate level and the final diagnosis of AA, particularly in perforated appendices. It can be considered for routine use in patients with undifferentiated abdominal pain in the emergency department setting.

An automated plasma D-lactate assay with a new sample preparation method to prevent interference from L-lactate and L-lactate dehydrogenase

Objective. To establish an automated plasma D-lactate assay without interference from L-lactate and L-lactate dehydrogenase (L-LDH). Methods and materials. The D-lactate assay was programmed as a 2-point endpoint assay on the Roche Modular P using the D-lactic acid kit from Biocontrol Systems, USA. In the chemical reaction, D-lactate was oxidized to pyruvate by NAD+ in the presence of D-lactate dehydrogenase. The resultant pyruvate was converted to alanine in the presence of alanine aminotransferase. The amount of NADH formed in the coupled reaction, measured by the change in the absorbance at 340 nm, was proportional to the concentration of D-lactate in the sample. Human serum albumin (HSA) solutions and plasma from pigs with experimentally-induced gut ischemia were used in this study. Blood samples were collected into Venosafe® tubes. Results. The D-lactate assay was linear up to 1.000 mmol/L in HSA solutions and plasma. The detection limit was 0.003 mmol/L. Within-run CVs ≤ 2.0% and total CVs ≤ 3.2% were obtained in the control material. Recovery was 87.1 ± 5.2 % (Mean ± SD). The L-LDH activity was completely inactivated in plasma samples by the addition of 20 µL of a 5 mol/L NaOH solution to 500 µL of plasma (pH 11.5). No interference could be detected from concentrations of bilirubin < 450 µmol/L, haemoglobin < 0.2 mmol/L or Intralipid® < 2.5 g/L. Conclusions. The performance of the established D-lactate assay meets the requirements to be implemented into hospital laboratories. The sample preparation method is simple, cheap and requires minimal labour.

Peritoneal and Plasma d‐lactate Concentrations in Horses with Colic

To evaluate the association between peritoneal fluid and plasma d-lactate concentration with variables used in the diagnosis and prognosis of horses with colic. Clinically healthy horses (n=6) and 90 horses with colic. Prospective cross-sectional study. D-lactate concentration was determined in peritoneal fluid and plasma of all horses. Information on other blood and peritoneal fluid variables, signalment, results from the physical examination, outcome, need for surgery, lesion location, and type was retrieved from medical records. Peritoneal D-lactate concentration was strongly correlated with plasma D-lactate concentration (r=0.71; P<.001). Peritoneal and plasma D-lactate concentrations were positively correlated with peritoneal (r=0.8; P<.001) and plasma L-lactate (r=0.33; P=.001) concentrations, respectively. Peritoneal D-lactate concentration was negatively correlated with survival to discharge (U=430.5; P<.001). Median peritoneal D-lactate concentration of horses with septic peritonitis (455.2 μmol/L) and horses with gastrointestinal rupture (599.5 μmol/L) were higher compared with horses with nonstrangulating obstructions (77.7 μmol/L). A cut-off concentration of peritoneal D-lactate of 116.6 μmol/L had a sensitivity of 0.813 and a specificity of 0.651 to differentiate between nonstrangulating and strangulating obstructions. Peritoneal D-lactate concentration may be more useful for identifying horses with strangulating obstructions (high sensitivity, low probability of a false negative) than to ruling out strangulating obstruction (moderate specificity, high probability of a false positive).

Effects of simulated weightlessness on the intestinal mucosal barrier of rats

This study employed a rat tail-suspension model to investigate the effects of simulated weightlessness on the intestinal mucosal barrier. Twenty-four Wistar rats were randomly divided into control (CON), 14-day tail-suspension (SUS-14d), and 21-day tail-suspension (SUS-21d) groups ( n = 8 per group). Expression of occludin and zonula occludins-1 (ZO-1), proteins of the tight junction (TJ), in the intestinal mucosa was measured by immunohistochemical analysis, Western blotting, and mRNA fluorescent quantitation PCR. Plasma concentrations of diamine oxidase (DAO) and d-lactate were determined using an enzymatic spectrophotometric assay. Expression of occludin and ZO-1 was reduced in the SUS-14d and SUS-21d groups as compared to the CON group, with lowest expression observed in the SUS-21d group ( P < 0.01). Examination by transmission electron microscopy (TEM) of the jejunal epithelium revealed increased intercellular space, decreased TJ and desmosome densities, and destruction of microvilli in the SUS-14d and SUS-21d groups. Plasma DAO and d-lactate concentrations in the SUS-21d group were higher than those in SUS-14d group and significantly higher than those in the CON group ( P < 0.01). In all three groups, the expression of occludin and ZO-1 was found to correlate negatively with DAO ( P < 0.01) and d-lactate ( P < 0.01) concentrations. It is concluded that simulated weightless results in down-regulation of expression of TJ proteins in the rat intestinal mucosa. Simulated weightlessness is proposed to increase intestinal permeability through damage to the TJ.

Effects of simulated weightlessness on tight junction protein occludin and Zonula Occluden-1 expression levels in the intestinal mucosa of rats

This study investigated the tight junction (TJ) protein expression of the intestinal mucosa in a rat tail-suspension model under simulated weightlessness. Twenty-four Wistar rats were randomly divided into three groups: CON group (n=8), control; SUS-14 d group (n=8), tail-suspension for 14 days; SUS-21 d group (n=8), tail-suspension for 21 days. Occludin and Zonula Occluden-1 (ZO-1) expression levels were determined by immunohistochemical analysis and mRNA fluorescent quantitative PCR. Plasma levels of diamine oxidase (DAO) and d-lactate were determined using enzymatic spectrophotometry. Immunohistochemical results for occludin and ZO-1 showed disruption of the TJs in the intestinal mucosa in SUS-14 d and SUS-21 d groups. The expression levels of occludin and ZO-1 in SUS-21 d group were lower than those in SUS-14 d group, and significantly lower than those in CON group (Occldin: 0.86±0.02 vs 1.01±0.03 vs 1.63±0.03 and ZO-1: 0.82±0.01 vs 1.00±0.02 vs 1.55±0.01, P<0.01). Moreover, the levels of plasma DAO and d-lactate in SUS-21 d group were higher than those in SUS-14 d group, and significantly higher than those in CON group (DAO: 27.58±0.49 vs 20.74±0.49 vs 12.94±0.21 and d-lactate: 37.86±0.74 vs 28.26±1.01 vs 17.76±0.91, P<0.01). There were significant negative correlations between occludin or ZO-1 expression levels and DAO (r (2)=0.9014, r (2)=0.9355, P<0.01) or d-lactate levels (r (2)=0.8989, r (2)=0.9331, P<0.01). Occludin and Zo-1 were reduced in intestinal mucosa both in mRNA and protein levels in the rat tail-suspension model. The significant negative correlations between expression levels of TJs and plasma levels of DAO or d-lactate support the hypothesis that intestinal permeability is increased due to a decrease in TJ protein expression during tail-suspension from 14 days to 21 days.

Effects of penehyclidine hydrochloride on rat intestinal barrier function during cardiopulmonary bypass

To test the ability of penehyclidine hydrochloride (PHC) to attenuate intestinal injury in a rat cardiopulmonary bypass (CPB) model. Male Sprague-Dawley rats were randomly divided into six groups (eight each): sham-operated control; sham-operated low-dose PHC control (0.6 mg/kg); sham-operated high-dose PHC control (2.0 mg/kg); CPB vehicle control; CPB low-dose PHC (0.6 mg/kg); and CPB high-dose PHC (2.0 mg/kg). Blood samples were collected from the femoral artery 2 h after CPB for determination of plasma diamine oxidase (DAO), D-lactate and endotoxin levels. Spleen, liver, mesenteric lymph nodes and lung were removed for biochemical analyses. Intestinal tissue ultrastructure was examined by electron microscopy. In the sham-operated groups, high- and low-dose-PHC had no significant impact on the levels of DAO, D-lactate and endotoxin, or the incidence of intestinal bacterial translocation (BT). Serum levels of DAO, D-lactate, endotoxin and the incidence of intestinal BT were significantly increased in the surgical groups, compared with the sham-operated groups (0.543 ± 0.061, 5.697 ± 0.272, 14.75 ± 2.46, and 0/40 vs 1.038 ± 0.252, 9.377 ± 0.769, 60.37 ± 5.63, and 30/40, respectively, all P < 0.05). PHC alleviated the biochemical and histopathological changes in a dose-dependent manner. Serum levels of DAO, D-lactate, and endotoxin and the incidence of intestinal BT in the high-dose PHC group were significantly lower than in the low-dose PHC group (0.637 ± 0.064, 6.972 ± 0.349, 29.64 ± 5.49, and 14/40 vs 0.998 ± 0.062, 7.835 ± 0.330, 38.56 ± 4.28, and 6/40, respectively, all P < 0.05). PHC protects the structure and function of the intestinal mucosa from injury after CPB in rats.

D-lactate as a marker of venous-induced intestinal ischemia: An experimental study in pigs

Background Intestinal ischemia is difficult to diagnose. The search for biomarkers has led to an increased interest in d-lactate. d-lactate measured in higher concentrations arises from bacterial fermentation in the gastrointestinal tract. Permeable intestinal wall is an early consequence of intestinal ischemia, which allows d-lactate to enter the portal circulation. Methods The superior mesenteric vein was clamped in eight pigs for two hours to induce ischemia of the intestine. Eight sham-operated pigs served as controls. Systemic and portal plasma d- and l-lactate, l-LDH and leukocytes were measured. Results Plasma d-lactate increased significantly and nearly simultaneously in the systemic and portal circulation. After 75 min, samples from the jugular vein showed concentrations of .019 ± .008 mmol/L in the sham group and .042 ± .022 mmol/L in the intervention group ( P = .023). A similar significant effect was seen in the portal circulation after 90 min. l-lactate increased five minutes after clamping in the portal circulation, with values of 3.396 ± 1.119 mmol/L in the intervention group compared to 1.696 ± .483 mmol/L in the control group ( P = .006). l-LDH increased significantly in the intervention group, while leukocytes were unaffected. l-LDH and l-lactate in plasma led to an overestimation of d-lactate if not handled. Conclusion Both systemic d- and l-lactate were markers of venous-induced intestinal ischemia. We speculate that d-lactate may be a valuable aid to the clinician in search of the anaerobic focus, because it may be more specific for mesenteric ischemia than l-lactate, in the sense that it is of bacterial origin.

Closing the anion gap: Contribution of d-lactate to diabetic ketoacidosis

Background A high anion gap in diabetic ketoacidosis (DKA) suggests that some unmeasured anions must contribute to the generation of the anion gap. We investigated the contribution of d-lactate to the anion gap in DKA. Methods Diabetic patients with and without DKA and high anion gap were recruited. Plasma d-lactate was quantified by HPLC. Plasma methylglyoxal was assayed by liquid chromatography-tandem mass spectrometry. Results The plasma fasting glucose, β-hydroxybutyrate, and blood HbA1c levels were highly elevated in DKA. Plasma anion gap was significantly increased in DKA (20.59 ± 6.37) compared to either the diabetic (7.50 ± 1.88) or the control group (6.53 ± 1.75) ( p < 0.001, respectively). Moreover, plasma d-lactate levels were markedly increased in DKA (3.82 ± 2.50 mmol/l) compared to the diabetic (0.47 ± 0.55 mmol/l) or the control group (0.25 ± 0.35 mmol/l) ( p < 0.001, respectively). Regression analysis demonstrated that d-lactate was associated with acidosis and anion gap ( r = 0.686, p < 0.001). Conclusions Plasma d-lactate levels are highly elevated and associated with metabolic acidosis and the high anion gap in DKA. Laboratory monitoring of d-lactate will provide valuable information for assessment of patients with DKA.

Functional and morphological structure changes in the gut barrier during cholinesterase inhibitor intoxication and therapeutic effect of benthiactzine in rats

To investigate the functional and morphological structure changes in the gut barrier of rats induced by cholinesterase inhibitor VX poisoning, and the therapeutic effect of benthiactzine. Forty male Wistar rats were randomly divided into five groups: normal saline control group, VX poisoning (model) group, benthiactzine 1, 3, 9 mg/kg treatment groups, with 8 rats in each group. In the benthiactzine treatment groups, different dosages of the drug were respectively given (intraperitoneal injection) 5 minutes after VX poisoning (13 microg/kg subcutaneous injection). The plasma concentration of D-lactate and the diamine oxidase (DAO) activity, which reflected the gut barrier function, were measured at 3 hours after VX poisoning. At the same time point, the specimens from jejunum and ileum were harvested. The morphological changes in the intestinal mucosa were determined with light microscope and electron microscope. After VX poisoning, the plasma D-lactate concentration and the DAO activity in model group were significantly increased compared with those of control group [D-lactate concentration in model group was (87.752 + or - 22.906) mg/L which was higher than that of control group (29.072 + or - 6.546) mg/L; DAO activity in model group was (6.72 + or - 0.93) U/L which was higher than that of control group (2.99 + or - 0.43) U/L, both P<0.01]. These values could be decreased dose-dependently after benthiactzine 1, 3, 9 mg/kg administration after the VX poisoning. Furthermore, the increase in D-lactate (45.290 + or - 11.141) mg/L and DAO activity (3.17 + or - 0.68) U/L could be totally reversed by 9 mg/kg of benthiactzine (both P<0.01). In model group, the intestinal mucosal epithelial injury was obvious at 3 hours after VX poisoning as shown under light microscope, including diminution of the mucosal thickness and the height of villi in jejunum and ileum, interstitial edema, angiotelectasis. Also electronic microscopic examination revealed damaged organelles and cell tight junction of mucosal epithelium. These pathological changes in intestine could be inhibited by benthiactzine in dose-dependent manner. The gut barrier function in rats was seriously damaged by the cholinesterase inhibitor agents poisoning, as a result of injury to intestinal mucosa and increase of intestinal permeability. Benthiactzine exerts protection against functional and morphological structure damages of the gut barrier during intoxication.

Effect of probiotics preconditioning on intestinal mucosal barrier function after cardiopulmonary bypass in rats

Objective To investigate the effect of probiotics preconditioning on intestinal mucosal barrier function in a rat model of cardiopulmonary bypass (CPB) . Methods Twenty-four adult male SD rats weighing 350-450 g were randomly divided into 3 groups ( n = 8 each) : group Ⅰ sham operation ( group S); group Ⅱ CPB and group Ⅲ probiotics + CPB. CPB was established between left carotid artery and right jugular vein and maintained for 60 min. Croup Ⅲ received intragastric instillation of probiotics 2 ml once a day for 7 consecutive days before CPB. Blood samples were collected at 2 h after CPB was terminated for determination of plasma D-lactate, TNF-and IL-6 concentrations and diamine oxidase (DAO) activity. Venous blood was obtained from portal vein for determination of LPS concentration and cultured. Liver, pancreas, spleen, kidney and mesenteric lymphnode (MLN) specimens were obtained under sterile condition and cultured for bacterial growth. The mucous membrane of small intestine was examined with electron microscope. Results CPB significantly increased plasma DAO activity, and D-lactate, IPS, TNF-α and IL-6 concentrations and the rate of bacteria-positive culture of portal venous blood, liver, MLN, lung and kidney in group Ⅱ as compared with group S. Probiotics preconditioning significantly attenuated the above-mentioned CPB-induced changes. Microscopic examination showed that probiotics preconditioning significantly ameliorated CPB-induced damage to the epithelium of the small intestine. Conclusion Probiotics preconditioning can significantly attenuate CPB-induced inflammatory response and protect the intestinal mucosal barrier function. Key words: Probiotics; Ischemic preconditioning; Cardiopuhnonary bypass; Intestinal mucosa

A case of D-lactic acid encephalopathy associated with use of probiotics

A five year old girl was admitted to the hospital for evaluation of intermittent ataxia. She had undergone serial resections of the small intestine after birth, resulting in short bowel syndrome. Lactomin was prescribed for watery diarrhea at twice the regular dose 2 weeks before the onset of neurologic symptoms. D-lactic acidosis was diagnosed on the basis of a plasma D-lactate level of 5.537 mmol/l. Lactomin was discontinued, and she was treated with sodium bicarbonate and oral antibiotics. The probiotics the patient had taken were likely the cause of D-lactic acidosis and should therefore be avoided in patients with short bowel syndrome.

Bacterial translocation and change in intestinal permeability in patients after abdominal surgery

The purpose of this study was to investigate bacterial translocation and change in intestinal permeability in patients after abdominal surgery. Sixty-three patients undergoing elective abdominal surgery were enrolled in the study. Blood samples were collected prior to operation and 2, 24, 48 h after surgery for bacterial culture, microbial DNA extraction, plasma D-lactate and endotoxin measurement. PCR analysis was performed after DNA extraction, with beta-lactosidase gene of E. coli and 16S rRNA gene as target genes. All patients were observed for a period of 30 days for infectious complications. Our results showed that no bacterial DNA was detected before surgery, but after operation it was found in 12 patients (19.0%). Bacterial DNA was detected in 41.7% (10/24) of SIRS patients and 5.1% (2/39) of non-SIRS patients (P<0.01). About 83.3% of PCR-positive patients developed systemic inflammatory response syndrome (SIRS), but only 27.5% of PCR-negative patients did so (P<0.01). Two thirds of PCR-positive patients developed infectious complications, while none of PCR-negative patients did (P<0.01). The blood culture was positive only in 3 patients (4.8%), who were all PCR-positive. E. coli DNA was found in 66.7% of the PCR-positive patients. The plasma levels of D-lactate and endotoxin were elevated significantly 2, 24 and 48 h after operation in PCR-positive patients, with a significant positive correlation found between them (r=0.91, P<0.01). It is concluded that increased intestinal permeability was closely related with bacterial translocation. Intestinal bacterial translocation (most commonly E. coli) might occur at early stage (2 h) after abdominal surgery. Postoperative SIRS and infection might bear a close relationship with bacterial translocation.

Soluble intercellular adhesion molecule-1, D-lactate and diamine oxidase in patients with inflammatory bowel disease

To study the levels of serum soluble intercellular adhesion molecule-1 (sICAM-1), plasma D-lactate and diamine oxidase (DAO) in patients with inflammatory bowel disease (IBD), and the potential clinical significance. Sixty-nine patients with IBD and 30 healthy controls were included in this study. The concentration of sICAM-1 was detected with enzyme-linked immunosorbent assay, the level of D-lactate and DAO was measured by spectroscopic analysis, and the number of white blood cells (WBC) was determined by routine procedure. The levels of sICAM-l, DAO, and WBC in IBD patients were significantly higher than those in the control group (P < 0.01). sICAM-l in IBD patients was found to be closely related to the levels of DAO and D-lactate (212.94 +/- 69.89 vs 6.35 +/- 2.35, P = 0.000), DAO 212.94 +/- 69.89 vs 8.65 +/- 3.54, P = 0.000) and WBC (212.94 +/- 69.89 vs 7.40 +/- 2.61, P = 0.000), but no significant difference was observed between patients with ulcerative colitis and patients with Crohn's disease. The post-treatment levels of sICAM-l, D-lactate and WBC were significantly lower than before treatment (sICAM-l 206.57 +/- 79.21 vs 146.21 +/- 64.43, P = 0.000), (D-lactate 1.46 +/- 0.94 vs 0.52 +/- 0.32, P = 0.000) and (WBC 7.24 +/- 0.2.33 vs 5.21 +/- 3.21, P = 0.000). sICAM-1, D-lactate and DAO are closely related to the specific conditions of IBD, and thus could be used as a major diagnostic index.

Analytical investigation: Assay of d-lactate in diabetic plasma and urine

Objective In this study we developed a 96-micro plate enzymatic assay for d-lactate in plasma and urine. Methods d-lactate was assayed enzymatically with a UV-spectrophotometer in plasma from 38 and in urine from 37 diabetics and from 42 non-diabetic controls. Results The within-run coefficients of variations (CV) were 2.6% for plasma and 5.7% for urine. The between run CVs were 6.8% for plasma and 6.7% for urine. The mean recovery with standard deviation (S.D.) was 107.4 ± 7.3% for plasma and 100.1% ± 6.7% for urine. The plasma d-lactate in diabetics were (mean ± S.D.) 39.6 ± 23.7 μM. We found significant difference between the urinary d-lactate in controls and diabetics (18.2 ± 12.0 vs. 35.9 ± 24.2 μM/mM creatinine, p < 0.0001). Conclusions The assay proved reliable with acceptable precision and recovery. Results suggest that diabetics have elevated urinary and plasma d-lactate as compared to controls.

Automated assay for plasma D-lactate by enzymatic spectrophotometric analysis with sample blank correction

D-lactate is essentially a product of bacterial metabolism, and its assessment in plasma has been mainly used to diagnose D-lactic acidosis in patients with short bowel syndrome. In the last few years, there has been growing interest in the use of subclinical elevations of D-lactate concentrations as a diagnostic tool in a variety of clinical conditions such as ischaemia, trauma or infection. An endpoint enzymatic spectrophotometric assay to measure plasma D-lactate with a sample blank correction was validated on our routine clinical chemistry analyser (Olympus AU640). An ultrafiltration procedure was used in samples with a high L-lactate dehydrogenase (L-LDH) activity in order to avoid underestimation of the D-lactate concentration, when a sample blank was processed. The intra- and inter-assay imprecision were <5.1% and <13.3%, respectively and the mean recovery for the D-lactate assay was 95% (range 88-103%). Samples with L-LDH activity greater than 1500 IU/L required the use of ultrafiltration devices. Plasma D-lactate concentration in our 'non-diseased' paediatric population showed a non-Gaussian distribution--95th percentile equal to 19 micromol/L--and no difference based on gender or age was observed. We have established an accurate, sensitive and precise routine assay for D-lactate measurement in plasma. The assay was used to formulate paediatric reference ranges and will be used to assist clinicians to evaluate 'D-lactate toxicity' in patients with a variety of conditions such as short bowel syndrome, small bowel transplantation and as an early marker of intestinal ischaemia.

Protective effect of ethyl pyruvate on barrier function of intestinal mucosa in dogs with septic shock

To investigate the effect of ethyl pyruvate on barrier function of intestinal mucosa in dogs with septic shock. Twenty dogs with septic shock induced by lipopolysaccharides(LPS) were randomly divided into two groups. Dogs randomly received placebo (Ringer's solution, control group, n=8) or ethyl pyruvate in lactated Ringer's solution (0.05 g/kg loading dose over 10 mins, thereafter 0.05 g.kg(-1).h(-1) for 12 hours, EP treatment group, n=12). The diamine oxidase(DAO) activity and D-lactate content were detected at the 0, 8 th, 12 th and 24 th hour of septic shock. Animals were sacrificed at the 24 th hour after septic shock and the jejunal tissue was taken for histopathological examination. The levels of plasma DAO and D-lactate were significantly elevated in both groups after septic shock than those before septic shock. The changes in intestinal parameters of hemoperfusion and permeability in EP treatment group were significantly lowered than those in control group. Inflammation of small intestinal mucosa was more severe in control group than that in EP group, and the pathologic score was significantly lower in EP group(2.33+/-0.25) than that in control group(3.39+/-0.38)(P<0.05). Ethyl pyruvate can lessen intestinal permeability and protect intestinal barrier function in dogs with septic shock.