Serum L-lactate Research Articles

Acid–base status and serum l-lactate in growing/finishing bull calves fed different high-grain diets

This study evaluated the influence of diet grain mix on the serum acid–base balance and productive performance of calves maintained on high-grain diets in a commercial feedlot system, monitoring progress over the entire 140-day productive cycle (i.e. both the growing and finishing periods). Thirty 14-week-old Belgian Blue bull calves were randomly allotted in equal numbers to one of three experimental groups defined by whether the cereal grain in their diet was predominantly corn (group C), predominantly barley (group B), or predominantly a mixture of corn and barley in approximately equal proportions (group CB). Blood pH, pCO 2, HCO 3 −, base excess and serum l-lactate were determined, as were several productive performance variables. The three groups differed significantly with respect to their weights at the end of the growing period (CB > C > B), but not in final weight; group B gained significantly more weight and had a lower daily intake than either group C or group CB during the finishing period. At no time during the study period was altered ruminal function suggested by either clinical signs or blood parameters, possibly because of the relatively high crude protein (CP) contents of the feeds and the use of barley straw as forage. Nevertheless, HCO 3 − and base excess were significantly higher in group C than in the other groups during the growing period, suggesting that supplementation of a high-CP corn-based diet with bicarbonate could lead to alkalotic blood base values (group C was the only group to receive bicarbonate supplement in this study). Also, in group CB HCO 3 − and base excess were generally lower than in the other groups during both the growing and finishing periods, much of the time exhibiting a falling trend compatible with the use of blood bases to counteract overproduction of ruminal acids; this behaviour, which may have been due to the lower dietary fibre content of the CB diet, does not support claims that diets with equal proportions of rapidly and slowly digested starch sources are more beneficial than those including only one of these starch source types. Serum l-lactate levels were almost invariably higher in group B than in group C, with group CB in between, in both the growing and the finishing periods; and a significant time × group interaction during the growing period suggests that the time course of serum l-lactate was determined mainly by the influence of diet on microbial growth rates in the rumen. Negative correlation between blood pH and pCO 2 around the switch between growing and finishing regimens suggests that diet may possibly modulate the influence of breed on pCO 2, but further is required to examine this hypothesis.

Effects of malate supplementation on acid-base balance and productive performance in growing/finishing bull calves fed a high-grain diet

This study investigated the effects of malate supplementation on blood acid-base balance and serum lactate levels in a 137-day feedlot experiment with bull calves. Animals were allotted to one of two experimental groups: (1) A control group (no supplementation), and (2) a group receiving a salt of DL-malic acid. Blood pH, pCO2, HCO3 −, base excess, serum L-lactate and productivity parameters were evaluated. Our data reveal that under the conditions of the present experiment malate supplementation did not have any significant effect on productivity parameters by comparison with non-supplemented animals. As regards acid-base balance, no significant effects attributable only to malate were observed. In conclusion, the time-course and the overall means of serum L-lactate for both groups in both growing and finishing periods (0.44 ± 0.04 mmol/l and 0.39 ± 0.02 mmol/l, respectively, for control animal; and 0.54 ± 0.03 mmol/l and 0.49 ± 0.01 mmol/l, respectively, for supplemented animals) suggests that malate does not have any beneficial effects in animals fed a diet of similar characteristics to that given in this study.

Malic acid supplementation in growing/finishing feedlot bull calves: Influence of chemical form on blood acid–base balance and productive performance

The aim of the present study was to evaluate the effects of two chemical forms of malate (malic acid and a commercial malate salt) on acid–base balance and productive performance in cattle maintained in a commercial feedlot system, taking into account the entire productive cycle (i.e., the growing and finishing periods). Thirty-eight Belgian Blue bull calves were utilized for a 148-day feedlot study. Animals were allotted randomly to one of three experimental groups: (1) control group (C, no supplementation, n = 10), (2) dl-malic acid supplementation (MA, n = 14; 4 g/kg DM basis) and (3), supplementation with a commercial salt of dl-malic acid (MS, n = 14; 4 g/kg DM basis). Blood pH, pCO 2, HCO 3 −, base excess (BE) and serum l-lactate were determined. Productive data were also evaluated as complementary information for understanding internal changes associated with supplementation. Although no differences (P>0.1) were found in performance parameters, results were numerically better for supplemented animals than for controls. The efficiency of the organic acid supplementation varies depending on its chemical form and on productive stage: while similar results were observed using the salt form or the free acid in the growing period, better results were obtained with the acid form in the finishing period. Looking at blood parameters, the malate salt seems to be more effective than the acid form due to the fact that the latter tended to decrease blood bases (although the possibility that the malate salt may cause blood alkalinization due to decreased pCO 2 needs to be further explored). Finally, the effect of supplementation on blood l-lactate was shown (P<0.05) from the first week of the study: controls showed higher values than supplemented animals. In the growing period, differences were observed between C and MA steers, and between C and MS in the finishing period. In our opinion, there is a clear need for research evaluating the effects of organic acids on ruminant health in vivo.

Elevation of serum l-lactate dehydrogenase B correlated with the clinical stage of lung cancer

To identify potential biomarkers related with lung cancer metastasis, conditional media (CM) proteins collected from a primary non-small cell lung cancer (NSCLC) cell line NCI-H226 and its brain metastatic subline H226Br were analyzed by one-dimensional electrophoresis (1-D PAGE) and matrix-assisted laser desorption/time of flight mass spectrometry (MALDI-TOF-MS). Twelve biomarkers were identified, of which l-lactate dehydrogenase B (LDHB) chain was significantly up-regulated in the CM of H226Br cell and was further validated in 105 lung cancer, 93 non-lung cancer, 41 benign lung disease, as well as 65 healthy individuals sera using enzyme-linked immunosorbent assay (ELISA). It was found that the levels of LDHB were specifically elevated in NSCLC sera compared with other groups and were progressively increased with the clinical stage. At the cutoff point 0.260 (OD value) on the receiver operating characteristic (ROC) curve, LDHB could comparatively discriminate lung cancer from benign lung disease and healthy control groups with sensitivity 81%, specificity 70% and total accuracy 76%. These findings demonstrated that secretome could open up a possibility to find, identify, and characterize novel biomarkers related with invasion and metastasis.

Diagnostic Value of Blood D-dimer Level in Acute Mesenteric Ischaemia in the Rat: An Experimental Study

The high mortality rate of mesenteric ischaemia is mainly due to delay in diagnosis. For this reason, it is of great importance to find a specific and rapidly elevating marker. The present study investigated the diagnostic value of blood D-dimer level as a potential marker for acute mesenteric ischaemia in a rat model. Thirty male Wistar albino rats were divided into three groups. Basal D-dimer and L-lactate levels were determined in the non-operative control group (I). In the operated control group (II), the superior mesenteric artery was simply manipulated, while the artery was ligated in Group III. Blood samples were drawn in all groups for D-dimer and L-lactate assays. Both Group II (p=0.016) and Group III (p=0.001) had significantly higher mean D-dimer levels in the first postoperative hour compared with the basal level in Group I. However, there was no difference between the levels in Groups II and III. The mean level in Group II in the sixth hour had dropped to a statistically insignificant level compared with the basal value, while the mean value in Group III kept rising during this period (p=0.001). Nevertheless, there was no significant difference between Groups II and III. On the other hand, the mean L-lactate level in the first postoperative hour in Group III was significantly higher than the basal level in Group I (p=0.003). No significant rises were recorded in Group II in the first and sixth postoperative hours. The difference between Groups II and III in the first hour was significant (p=0.005). Group III also had significantly higher mean serum L-lactate value in the sixth hour compared with both the basal value in Group I (p=0.001) and the sixth-hour value in Group II (p=0.003). These results do not adequately support the use of blood D-dimer level as an independent parameter in the diagnosis of mesenteric ischaemia due to arterial thrombosis. However, this parameter can be used together with other tests in eliminating the possibility of a thromboembolic event.

Serum l-lactate and pyruvate in HIV-infected patients with and without presumed NRTI-related adverse events compared to healthy volunteers

Nucleoside reverse transcriptase inhibitors (NRTIs) used in antiretroviral therapy may cause mitochondrial toxicity. Mitochondrial dysfunction leads to disturbance of the glucose metabolism, resulting in an accumulation of L-lactate (L) and pyruvate (P), with an enhanced L/P ratio. We analysed lactate and pyruvate blood samples of patients of our outpatient department. Aim of the analysis was to detect preliminary mitochondrial toxicity in patients on antiretroviral nucleoside analogues, which might result in disturbances of L, P, L/P ratio, bicarbonate (Bic) or beta-hydroxybutyrate/aceto-acetate (beta-HB/AA) ratios. Blood samples of L, P, Bic, beta-HB and AA were analysed in four groups of subjects. The first group (A) consisted of patients with presumed NRTI-related adverse events (n=21), the second group (B) consisted of patients without adverse events (n=28), the third group (C) were HIV-infected patients without antiretroviral therapy (n=6) and the last group (D) were healthy controls (n=12). The mean duration of NRTI-treatment was 18 months (range 0-78 months). The mean lactate level in group A was 2319 micromol/l (S.D. +/-1231, median 1741 micromol/l), in group B 1257 micromol/l (S.D. +/-607, median 1087), Group C 1285 (S.D. +/-451, median 1245 micromol/l) and 951 micromol/l (S.D. +/-270, median 979) in the healthy controls. No significant differences in pyruvate, L/P, Bic and beta-HB/AA were seen in the four groups. The mean lactate level in patients on stavudine was 1980 micromol/l (S.D. +/-1197) versus 1051 micromol/l (S.D. +/-395, P=0.01) in patients on zidovudine. All patients with lactate values above 2700 micromol/l (eight) experienced adverse events. Lactate levels were higher in patients with presumed NRTI-related adverse events. Furthermore, HIV patients receiving a stavudine containing antiretroviral therapy had higher lactate values than patients without stavudine. Although routine lactate measurement in all patients on antiretroviral therapy is not recommended, lactate measurement might be useful for follow up of patients with presumed NRTI-related adverse events and in patients with lactate levels above 2500 micromol/l. These patients require extra surveillance to evaluate if discontinuation of the current antiretroviral therapy is needed.

D-lactic acidemia and aciduria in pediatric and adult patients with short bowel syndrome

D-Lactate produced by abundant intestinal lactobacilli during acidotic episodes in short bowel (SB) patients is commonly regarded as a main factor in the pathogenesis of SB syndrome-associated (D-lactic) acidosis. Since we had observed that gram-positive bacteria, mainly lactobacilli, were abundant even in the absence of acidosis, we studied serum concentrations and urinary excretions of D- and L-lactate in young and adult SB patients, especially during nonacidotic periods. Serum L-lactate and urinary L-lactate excretion were similar in adults and children. Serum D-lactate and urinary D-lactate excretion were higher in SB children than in SB adults. Food consumption affects D-lactate production and alters D-lactic acidemia and aciduria. We conclude that D-lactate is frequently present in serum of SB patients even in the absence of acidosis. High serum concentrations and urinary excretions may reflect dietary factors in these patients.

γ-Glutamyltransferase in Hypernephroma

To the Editor. — Renal cell carcinoma is known to be associated with reversible hepatic dysfunction accompanied by hepatosplenomegaly in the absence of metastatic disease to the liver or spleen. 1,2 The syndrome has been reported to cause elevations in the levels of serum alkaline phosphatase, serum bilirubin, aspartate aminotransferase, alanine aminotransferase, and serum L-lactate dehydrogenase. A patient recently presented with the syndrome and elevation of the serum γ-glutamyl-transferase (GGT) level, a test that was introduced subsequent to previously reported cases. Report of a Case.— A 69-year-old woman with a history (18 years ago) of renal cell carcinoma and left nephrectomy came to the emergency department complaining of severe epigastric pain, weight loss, and early satiety. There was no history of alcohol abuse, drug or medication use, blood transfusion, or recent travel. Physical examination revealed an epigastric mass and splenomegaly. Serum chemistry values were as follows: L-lactate dehydrogenase, 375 U/L;

Bioluminescent flow sensors: L-lactate dehydrogenase activity determination in serum.

The catalytic activity of serum L-lactate dehydrogenase (LDH), was determined by monitoring the NADH produced by LDH with bacterial bioluminescent enzymes immobilized on a nylon coil. The LDH reaction of L-lactate with NAD took place in a flow-through mixing coil that preceded the bioluminescent detector coil. The response was linear from 1 to 5000 U/l at 37 degrees C and from 3 to 2000 U/l at 25 degrees C. The intra- and inter-assay reproducibility (CV%) were less than 10% and recovery range was 92% to 110%. The results agreed well with those obtained with a spectrophotometric method.

Intestinal ischemia: Treatment by peritoneal lavage with oxygenated perfluorochemical

Though the delivery of elemental oxygen to tissues ravaged by anaerobic infection may be useful, little data exists that suggests that such therapy may benefit ischemic tissue. We report the development of a model to test the question that peritoneal lavage with an oxygen containing solution may favorably influence occlusive intestinal ischemia. Adult Sprague-Dawley rats with Nembutal (sodium pentobarbital) anesthesia underwent midline laparotomy; a microvascular clamp was applied to the superior mesenteric artery (SMA); and an inflow and outflow lavage catheter was placed. Treatment groups included control rats undergoing SMA occlusion only without lavage, rats lavaged with albumin during SMA occlusion (medium control), and rats lavaged during SMA occlusion with oxygenated perfluorochemical FC-47 emulsified in albumin (O2-FC-47). The increase in serum L-lactate following occlusion was used as an index of intestinal injury whether the perfusate was maintained at room temperature (28 degrees C) or body temperature (37 degrees C). Beginning with time O, which corresponded to the time of unclamping, subsequent samples were collected at 15, 30, and 60 minutes after a 30-minute SMA occlusion. Sequential lactates in 13 control rats were 4.18, 4.10, 3.88, and 4.52 mmol/L. Albumin lavaged animals had values at 28 degrees C of 2.23, 1.35, 1.8, and 2.44 mmol/L and values at 37 degrees C of 2.22, 1.40, 2.07, and 3.21 mmol/L, respectively. With O2-FC-47 lavage the respective lactates were 1.89, 1.09, 1.32, and 1.44 mmol/L at 28 degrees C and 2.14, 2.19, 2.50, and 2.1 mmol/L at 37 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)