The Diagnostic Value of Cerebrospinal Fluid Lactic Acid Levels in Meningitis

Abstract: To assess the reliability of cerebrospinal fluid (CSF) lactate levels in children for differentiating between bacterial and viral meningitis, we measured the CSF lactate levels using the carboxylic acid analyzer, enzymatic method and colorimetric determination. Lactate determination by these methods is a highly reliable indicator of the presence or absence of bacterial meningitis. Moreover, the duration of elevated CSF lactate levels coincided with the clinical response to therapy.     

Correlation Studies of Morphological and Biochemical Parameters in Human Ejaculate in Various Andrological Diagnoses. 3rd Report: Correlations between Morphological and Biochemical Parameters

Untersuchungen zur Korrelation morphologischer und biochemischer Meßgrößen im menschlichen Ejakulat bei verschiedenen andrologischen Diagnosen. III. Mitteilung: Beziehungen zwischen morphologischen und biochemischen Parametern Als Abschluß einer umfangreichen Studie über morphologische und biochemische Meßgrößen im menschlichen Ejakulat wird das Ergebnis einer Untersuchung von Korrelationen zwischen diesen beiden Parametem mitgeteilt. Alle Untersuchungen der I.–III. Mitteilung zu diesem Problemkomplex sind am gleichen Untersuchungsmaterial vorgenommen worden. Alle Untersuchungen sind jeweils 10 Minuten nach der Ejakulation durchgeführt worden, nachdem das Ejakulat sich verflüssigt hatte; das bedeutet, daß diese Intervallzeit für alle vorgelegten Untersuchungen in gleicher Weise zutrifft und daß die Untersuchungen Einblick in die aktuelle Situation des Stoffwechsels zu diesem Zeitpunkt gestatten. Es kann unter Berücksichtigung der Ergebnisse, für die eine statistische Signifikanz von p < 0,05 ermittelt werden konnte, festgestellt werden, daß höhere Fruktosekonzentrationen mit einer niedrigeren Spermatozoendichte einhergehen; gleichzeitig ergibt sich, daß die höheren Fruktosekonzentrationen mit einem höheren Prozentsatz an unbeweglichen und an pathologisch veränderten Spermatozoen korrelieren. Ähnliche interessante Beziehungen lassen sich für einige Substrate und Enzyme herstellen. Hier ist die wesentlichste Feststellung, daß bei den z.T. erhöhten Aktivitäten für PGK, PGI und ATPase bei höherer Spermatozoendichte die Möglichkeit einer Diffusion der Enzyme aus den zellulären Bestandteilen zu diskutieren ist, da die Analysen im Spermaplasma vorgenommen worden sind. Daraus wird die Schlußfolgerung gezogen, in einer weiteren Versuchsreihe an einem neuen Untersuchungsmaterial entsprechende Messungen in den zellulären Elementen des Ejakulates (Spermatozoen, Rundzellen) vorzunehmen.     

Increased concentrations of L-lactate in the rectal lumen in patients undergoing cardiopulmonary bypass

Background. Gut ischaemia may contribute to morbidity in patientsafter cardiopulmonary bypass (CPB), but little is known aboutthe metabolic state of the large bowel in such patients. Thereforewe estimated the concentrations of L-lactate and in rectal mucosa in patients undergoing cardiac surgery withor without the use of CPB. Methods. Patients undergoing coronary artery bypass grafting(CABG) (n=12) or off-pump CABG (n=10) were subjected to equilibriumdialysis of the rectal lumen during the procedure and in thefirst 4 h afterwards. Dialysate concentrations of L-lactateand were measured using an auto-analyser and compared with values obtained in healthy subjects (n=10). Results. During CPB, a 2- to 3-fold increase in luminal concentrationsof L-lactate was observed (CABG vs off-pump CABG, P=0.05; CABGvs healthy subjects, P<0.01). The dialysate concentrationsof L-lactate were higher than the mean systemic values (luminal–arterialgradient mean (SD) 0.9 (1.0) mmol litre^–1, P<0.05),and the two values were positively correlated (P<0.05). LuminalL-lactate concentrations remained elevated 4 h after the operation.In contrast, dialysate was equally high in patient and control groups and substantially higher thanvalues observed in arterial blood. Conclusions. Uncomplicated CPB is associated with moderate butsustained increases in luminal concentrations of L-lactate inthe rectum, indicating metabolic dysfunction of the mucosa inthe large bowel. Part of this study was presented at the 27th Congress of theScandinavian Society of Anaesthesiology and Intensive Care Medicine,Helsinki, Finland, 2003.     

Adverse biochemical and physiological effects of prostacyclin in experimental brain oedema

BACKGROUND: Prostacyclin (PGI2) and its stable analogues are known to reduce capillary hydraulic permeability. This study explores the biochemical and physiological effects of i.v. infusion of low-dose PGI2 in an experimental model of vasogenic brain oedema. METHODS: Twenty-seven anaesthetized and mechanically ventilated piglets with brain oedema induced by intrathecal injection of lipopolysaccharide (LPS) were used. Five of the animals received a continuous infusion of PGI2 (1 ng kg(-1) min(-1)) i.v. Four microdialysis catheters were placed in the brain to measure interstitial concentrations of glucose, lactate, and glycerol. Mean arterial pressure (MAP), intracranial pressure (ICP) and temperature were monitored continuously. Low-dose infusion of PGI2 started 1 h before the LPS injection and was constant during the study period. RESULTS: Intracranial pressure increased significantly in animals treated with PGI2. The increase in ICP was associated with significant cerebral biochemical changes: decrease in glucose, increase in lactate, increase in lactate/glucose ratio and increase in glycerol. CONCLUSION: In LPS-induced brain oedema i.v. infusion of low-dose PGI2 caused a further increase in ICP and a perturbation of energy metabolism, indicating cerebral ischemia and degradation of cellular membranes.     

Skeletal muscle and hormonal adaptations to circuit weight training in untrained men

Twelve men either performed 10 weeks of timed circuit weight training 3 days week(-1) (CWT; n=8; X+/-SE; age=23.6+/-1.8 years), or were part of a sedentary control group (n=4; age=20.5+/-1.0 years). Significance was P<0.05 for all analyses. The CWT program significantly increased 1 repetition maximum (1 RM) strength for nine of 10 exercises (15-42%). Although no body composition measure significantly changed for the CWT group, low-to-moderate effect sizes were evident for body weight, lean body mass, and relative fat. CWT did not alter percent fiber type, but did increase cross-sectional areas for type IIA fibers (microm(2); pre=5988+/-323, post=7259+/-669). Relative (%) myosin heavy-chain (MHC) expression increased for MHC IIa (pre=42.5+/-2.7, post=50.1+/-2.6), and decreased for MHC IIb (pre=21.8+/-2.8, post=15.4+/-2.4) for the CWT group. Serum testosterone, cortisol, and the testosterone/cortisol ratio did not change at any time for the CWT group. None of the measured variables changed for the control group. These data indicate that for untrained subjects, CWT of the type used resulted in improved muscular strength and a tendency toward increased lean mass. Compared with other types of weight training, fewer adaptations of the muscle fibers were evident. This is likely due in part to the relatively low loads used with this type of resistance exercise.     

Effects of hyperthermia on the metabolic responses to repeated high-intensity exercise

In this study, we investigated the metabolic and performance responses to hyperthermia during high-intensity exercise. Seven males completed two 30-s cycle sprints (SpI and SpII) at an environmental temperature of 20.6 (0.3) °C [mean (SD)] with 4 min recovery between sprints. A hot or control treatment preceded the sprint exercise. For the hot trial, subjects were immersed up to the neck in hot water [43°C for 16.0 (3.2) min] prior to entering an environmental chamber [44.2 (0.8)°C for 30.7 (7.1) min]. For the control trial, subjects were seated in an empty bath (15 min) and thereafter in a normal environment [20.2 (0.6)°C for 29.0 (1.9) min]. Subjects core temperature prior to exercise was 38.1 (0.3)°C in the hot trial and 37.1 (0.3)°C in the control trial. Mean power output (MPO) was significantly higher in the hot condition for SpI [683 (130) W hot vs 646 (119) W control (P<0.025)]. Peak power output (PPO) tended to be higher in the hot trial compared with the control trial for SpI [1057 (260) W hot vs 990 (245) W control (P=0.03, NS)]. These differences in power output were a consequence of a faster pedal cadence in the hot trial (P<0.025). There were no differences in sprint performance in SpII in the hot trial compared to the control trial; however, MPO was significantly reduced from SpI to SpII in the hot condition but not in the control condition (P<0.025). Plasma ammonia was higher in the hot trial at 2 min post-SpI [169 (65) mol l^-1 hot vs 70 (26) mol l^-1 control (P<0.01)], immediately and at 2 min post-SpII [231 (76) mol l^-1 hot vs 147 (72) mol l^-1 control (P<0.01)]. Blood lactate was higher in the hot trial compared with the control trial at 5 min post-SpII (P<0.025). The results of this study suggest that an elevation in core body temperature by 1°C can improve performance during an initial bout of high-intensity cycle exercise but has no further beneficial effect on subsequent power production following a 4-min recovery period.     

Physiological responses during cycling with noncircular "Harmonic" and circular chainrings

The aim of the present study was to compare physiological data obtained during cycling using a noncircular "Harmonic" chainring versus a standard circular chainring over a range of speeds and slopes in endurance-trained cyclists. Thirteen male subnational cyclists (16–45 years) performed two maximal graded exercises on their own bicycle: one with a circular chainring, the other with a Harmonic chainring with the same gearwheel (52 teeth). The two chainrings were randomly assigned to avoid learning effects. The tests were carried out on a simulator. Speeds and/or slopes were increased every 2 min 30 s until exhaustion of the subject. Ventilation, oxygen uptake, carbon dioxide output, respiratory exchange ratio, and heart rate were continuously measured during the tests. Blood lactate concentration was measured during the last 30 s of each level. No significant difference was observed in any of the submaximal parameters measured during the tests (P>0.05). Similarly, maximal values were not statistically different (P>0.05). In conclusion, although the design of the Harmonic chainring was based on optimization analysis, comparison of the physiological response in this study did not translate into an advantage of the Harmonic over circular chainring during submaximal and maximal pedaling in trained cyclists.     

Differential effects of “Advanced glycation endproducts” and β-amyloid peptide on glucose utilization and ATP levels in the neuronal cell line SH-SY5Y

Summary. -amyloid peptide (A) and Advanced glycation endproducts (AGEs) are components of the senile plaques in Alzheimers disease patients. It has been proposed that both AGEs and A exert many of their effects, which include the upregulation of pro-inflammatory cytokines, through RAGE (receptor for advanced glycation endproducts). To investigate whether A and AGEs cause similar or identical effects on cell survival and energy metabolism, we have compared the effects of a model-AGE and A on cell viability, ATP level, glucose consumption and lactate production in the neuroblastoma cell line SH-SY5Y. The results show that AGEs and A increase glucose consumption and decrease ATP levels in a dose dependent manner. Furthermore, both compounds decrease mitochondrial activity measured by the MTT assay. However, only AGEs decrease the number of cells and significantly increase lactate production. These data indicate that both AGEs and A can cause differential disturbances in neuronal metabolism, which may contribute to the pathophysiological findings in Alzheimers disease. However, their signalling pathways are apparently quite distinct, a fact which should stimulate a more detailed investigation in this field, e.g. for the purpose of a rational design of potential neuroprotective RAGE antagonists.     

Phospholipids reduce adhesion formation in the rabbit uterine horn model

Objective: To access the ability of intraperitoneal phospholipids to reduce adhesions in a standardized model for gynecologic operations.

Design: A randomized, experimental, blinded study using the double uterine horn model.

Setting: Academic animal research laboratory.

Animal(s): Thirty-three Chinchilla rabbits.

Intervention(s): Phospholipids or Ringer’s lactate were intraperitoneally administered after bilateral uterine horn injury.

Main Outcome Measure(s): After 10 days, adhesions were evaluated concerning area and strength as well as scores describing tenacity and degree.

Result(s): Phospholipids (median 102.1 mm²) significantly reduce adhesion areas in comparison to surgical controls (median 392.2 mm²) and Ringer group (median 323.8 mm²). Scores reflecting severity and degree of adhesions support this finding.

Conclusion(s): These results prove the efficacy of phospholipids in the double uterine horn model. Future clinical studies are recommended.     

Reproducibility of the blood lactate threshold, 4 mmol·l<Superscript>–1</Superscript> marker,heart rate and ratings of perceived exertion during incremental treadmill exercise in humans

The aim of this study was to investigate the reproducibility of blood lactate measurements, heart rate (HR) and ratings of perceived exertion (RPE) during treadmill exercise at speeds corresponding to the lactate threshold (v _Th,la-) and a fixed blood lactate concentration of 4 mmol·l^–1(v _la-_,4). Possible differences in reproducibility related to fitness levels were also investigated. A group of 20 men [mean (SD)] [age 20.5 (1.4) years] and 16 women [age 21.2 (0.9) years] took part in the study. The subjects performed two identical incremental exercise tests consisting of at least six 4 min stages. Blood lactate concentrations, HR and RPE were recorded at the end of each stage. Limits of agreement (LoA), correlation coefficients and 95% confidence intervals for the mean difference between tests were employed to investigate the level of agreement and reproducibility of blood lactate concentration, HR and RPE. For the group as a whole, the sample correlation coefficient for speed at v _Th,la- was r=0.88, and was r=0.92 for the speed at v _la-_,4. At v _Th,la -, the correlation coefficients for the moderately fit and unfit were r=0.94 and r=0.36, respectively, and at v _la-_,4 r=0.93 and r=0.68, respectively. The LoA for the moderately fit group indicated that a change of 1.62 km·h^–1 in v _Th,la- would be necessary to be considered a change in training status. For HR and RPE, relationships between the tests were generally poor. The LoA suggested that changes in scores must be unacceptably large. These findings cast doubt on the sensitivity of testing for change of blood lactate concentration, HR and RPE in this population. Electronic Publication