PURPOSE: To test the potential participation of pericytes in the regulation of capillary blood flow according to metabolic needs. METHODS: The authors measured the change in extracellular pH (pHo), intracellular pH (pHi), and contractile tone of cultured bovine retinal pericytes when the ambient carbon dioxide (CO2) level was changed. RESULTS: ...

The aim of this study was to investigate mucosal pH and lactate production in a porcine model of ischemia/reperfusion and sepsis using both tonometry and a technique for segmental intestinal perfusion. Eighteen pigs (17-23 kg) were anesthetized and mechanically ventilated. They were divided into three groups and followed for 4 ...

In normal venous blood plasma, the regression line of [H+] plotted against the PCO2 was linear against the square root of PCO2. Sequential measurements in venous and arterial blood of PCO2 and [H+] showed that the venous-arterial (V-A) difference in [H+] was linearly related to the V-A difference in the ...

We studied the effects of time delay on blood gases, pH, and base excess in blood stored in glass and plastic syringes on ice and the effects of resulting errors on calculated alveolar-to-arterial PO2 difference (A-aDO2). Matched samples of dog whole blood were tonometered with gas mixtures of 5% CO2-12% ...

AIM: To investigate the relation between common acid-base parameters and blood lactate concentrations and their prognostic importance in sick, ventilated neonates. METHODS: Two hundred and seventy eight serial simultaneous measurements of arterial acid-base status and blood lactate concentrations were carried out in 75 mechanically ventilated neonates with indwelling arterial catheters ...

A new membrane system evaluated in an enzyme electrode for monitoring of whole blood lactate under continuous flow conditions has been developed. The membrane confers functional haemocompatibility and has been coupled to an electrode based on amperometric detection of hydrogen peroxide with lactate oxidase interposed between the haemocompatible membrane acting ...

OBJECTIVE: To evaluate the effect of continuous venovenous hemofiltration with dialysis on lactate elimination by critically ill patients. DESIGN: Prospective, clinical study. SETTING: Surgical intensive care unit of a university hospital. PATIENTS: Ten critically ill patients with acute renal failure and stable blood lactate concentrations. INTERVENTIONS: Two-stage investigation: a) measurement ...

We observed simultaneous changes in lactate level and regional blood flow (rBF) in the brain of the anesthetized rabbit by using localized proton magnetic resonance spectroscopy (1H MRS) and laser Doppler flowmetry. The volume of interest of 0.5 ml for 1H MRS contained mostly thalamic nuclei. During hypoxia peak area ...

BACKGROUND: This study evaluated the feasibility of blood gas analysis and electrolyte measurements during emergency transport prior to hospital admission. RESULTS: A portable, battery-powered blood analyzer was used on patients in life threatening conditions to determine pH, pCO2, pO2, sodium, potassium and ionized calcium. Arterial blood was used for blood ...

BACKGROUND: Modern rock climbers stress the importance of hand-to-rock contact strength as a factor for success in competitive sport climbing events, however, the degree of handgrip fatigue that occurs during difficult climbing and the time course of recovery from fatigue have not been previously described. The purpose of this study ...

OBJECTIVE: To test the hypothesis that saliva lactate concentrations may reflect those present in blood and that saliva lactate can be used as a very convenient and useful variable in the study of anaerobic metabolism. METHODS: Parallel determinations were made of lactate in saliva and in capillary blood samples, obtained ...

The purposes of this study were 1) to confirm whether there is a difference in the levels of blood lactate and ammonia after supramaximal uphill and downhill running for the same short duration and 2) to examine the relationship between peak blood lactate levels and work/lean body mass (LBM), as ...

This study used radioactive microspheres to examine blood flow distribution in the mammary and reproductive systems of hyperthermic (+1 degrees C), anesthetized laboratory rabbits at different stages of pregnancy and lactation. Ovarian, cervical and oviductal blood flows decreased by 20-30% during heat stress while vulval blood flow rose by 40%, ...

This study was designed to describe the physiological, psychophysical, and psychological responses of firefighters to firefighting drills in a training structure containing live fires. Fifteen male firefighters, wearing standard turnout gear which resulted in full encapsulation, performed two firefighting tasks (advancing fire hose, chopping wood) while inside the training structure. ...

Tissue perfusion is at risk during cardiac surgery and in the immediate postoperative period. The association of low blood flow with metabolic acidosis and accumulation of lactate perioperatively has been well established. With the improvements in cardiopulmonary bypass and overall hemodynamic management, severe peri- and postoperative hypoperfusion has become rare. ...

The feasibility of developing a portable device for immediate monitoring of physiologic lactate using Wired EnzyneTM technology was demonstrated. Ultimately, this device will provide critical data for monitoring and dictating the triage and therapy of wounded soldiers in the battlefield or injured civilian trauna patients. Recent publications have established the ...

Gut ischemia is often assessed by computing an imaginary tissue interstitial Ph from arterial plasma HCO3- and the PCO2 in a saline-filled balloon tonometer after equilibration with tissue PCO2 and (PtiCO2). PtiCO2 may alternatively be assumed equal to venous PCO2 (PVCO2) in that region of gut. The idea is that ...

The interrelationships between lactate and pH, nonadrenaline (NA), adrenaline (A) and dopamine (DA) were investigated in cord artery (CA) and vein (GV) blood at delivery. Sixty consecutive, spontaneous, vaginal deliveries with fetuses in cephalic presentation were assessed. Median gestational age at delivery was 40 weeks (range, 35-43). There were significant ...

The aim of this study was to investigate correlations between lactate concentrations in equine whole blood and plasma measured with Accusport1 and Yellow Springs Instruments (YSI2) (2300) methods. The effect of packed cell volume (PCV) on the accuracy of Accusport was also investigated. Blood samples were collected from Thoroughbred horses ...

To determine the effects of hyperglycemia and hyperinsulinemia on lactate production by adipocytes, healthy volunteers were studied during three experimental protocols. In protocol 1, the changes in interstitial lactate concentrations were measured by microdialysis (sc tissue) after oral glucose administration. The plasma lactate concentration increased by 39.4 +/- 6.0%, and ...

To assess net lactate release from dermal skin, seven lean, healthy men were studied after overnight fasting. Two microdialysis catheters were inserted in the upper dermal tissue, as ensured by ultrasound scanning, in the periumbilical area. Each catheter was calibrated in situ to get an estimate of the lactate concentration ...

OBJECTIVE: To examine the reproducibility of blood lactate-running speed curve parameters derived by a curve-fit equation and by linear interpolation from the results of 4-speed tests of sport horses under field conditions. DESIGN: Thoroughbreds completed 10 test pairs with 3 to 11 days between tests and retest. ANIMALS: 7 Thoroughbreds. ...

OBJECTIVES: CO2 content can be determined from the Pco2 in an acidified (forces all CO2 into solution) and diluted blood sample. However, Pco2 concentrations measured in conventional blood gas analyzers are only correct for samples with a significant buffer capacity (such as whole blood), so that mixing with the Pco2 ...

The pathogenesis of hyperlacticemia during sepsis is poorly understood. We investigated the role of lung, kidney, gut, liver, and muscle in endogenous lactate uptake and release during early endotoxemia in an intact, pentobarbital-anesthetized dog model (n = 14). Ultrasonic flow probes were placed around the portal vein and hepatic, renal, ...

Lactate is a metabolite that can safely and easily can be determined in fetal scalp blood using new microvolume (5-20 microliters) lactate meters. However, new lactate analysing methods need their own reference values. There are factors other than hypoxia that might increase fetal lactate levels, although this does not disqualify ...

OBJECTIVES: To determine whether changes in cardiac output, regional blood flow, and intracranial pressure during permissive hypercapnia are blood pH-dependent and can be attenuated by correction of intravascular acidemia. DESIGN: Prospective, controlled study. SETTING: Research laboratory. SUBJECTS: Female Marino ewes. INTERVENTIONS: Animals were instrumented with a pulmonary artery catheter, femoral ...

In newborn rabbits, the early cerebral metabolic changes caused by hypoxic-ischemic (H-I) insult was examined by using volume localized 1H-MRS (STEAM). Partial ischemia was caused by unilateral carotid artery ligation, and hypoxia was induced by 10% oxygen inspiration for 150 minutes. Lactate immediately increased after hypoxia induction and almost disappeared ...

The microscopic morphology, that is, total hyphal length and total number of tips, has been characterized during batch cultivations of Aspergillus oryzae. The specific growth rate estimated by measuring the total hyphal length (mu(h)) corresponds well with the specific growth rate estimated from dry weight measurements during cultures grown as ...

Peak blood lactate ([Labl]peak) and blood lactate concentration ([Labl]) vs. workload (W) relationships during acclimatization to altitude and in the deacclimatization were evaluated in 10 Caucasian lowlanders at sea level (SL0); after approximately 1 wk (Alt1wk), 3 wk (Alt3wk), and 5 wk (Alt5wk) at 5,050 m; and weekly during the ...

Decreased activity of complex I (NAD:ubiquinone oxidoreductase) is the most frequent biochemical finding associated with mutation at the base pair 3243 of the mitochondrial DNA. The mutation has been previously shown to lead to a defective translation. We hypothesized that due to an imperfect assembly of complex I subunits the ...

The stability of DA-5018, a capsaicin analog as a new non-narcotic analgesic, in plasma, blood, 4% human serum albumin (HSA), and isotonic Sørensen phosphate buffer at pH 7.4 containing dextran to make 3% ('the buffer'), the blood partition of DA-5018 between plasma and blood cells, and the factors influencing the ...

In the lactate biosensor, electrodeposited poly(o-phenylenediamine) serves as a convenient matrix for the immobilization of lactate oxidase, but does not provide sufficient discrimination from several interfering species present in physiological fluids. Their effect, however, can be eliminated by additional modification of the working Pt electrode with a bilayer of electrodeposited ...

Severe head injury is frequently associated with focal or global disturbances of cerebral blood flow and metabolism. Routine monitoring of intracranial pressure (ICP) and cerebral perfusion pressure (CPP) in these patients does not provide information about critically reduced local or global cerebral blood flow. Measurements of cerebral lactate difference, Lactate-Oxygen-Index ...

There is much controversy about the optimal bloodgas management of hypothermic patients, whether the hypothermia is caused by accidents or induced before operations. The surgeons and anestesiologists have acquired more clinical experience the last years when operating patients in hypothermia. The comparative physiology has given increased information about the blood ...

The purpose of this experiment was to investigate the lactate responses to roller skiing with double pole and diagonal stride techniques in eight collegiate or national level cross-country ski racers. Four-minute exercise stages were performed on a ski treadmill at 67, 94, 121, 148, and 174 m.min-1 on a 1.7% ...

OBJECTIVE: To establish the relationship between gut intramucosal pH and blood flow to the gut, gut oxygen delivery, and gut oxygen extraction ratio in a porcine model of peritonitis and hemorrhage. DESIGN: Prospective, controlled study. SETTING: Experimental laboratory in a university teaching hospital. SUBJECTS: Thirty pigs of both sexes, weighing ...

To define the value of serial measurements of blood lactate levels after trauma, the present study investigated the correlation between blood lactate, mortality, and organ failure in 129 trauma patients, including 100 intensive care unit (ICU) survivors and 29 ICU fatalities. On admission, injury severity score (ISS) was higher and ...

Correction of the acid-base balance in uremic patients during hemodiafiltration (HFD) may be biased by an inadequate monitoring of pH and blood gases. HDF performed with the two-chamber technique (PFD) generates pure ultrafiltrate (uf) unmixed with dialysate. We carried out 84 determinations of HCO3- levels in 15 different PFD patients ...

OBJECTIVE: To determine fetal scalp blood lactate with a new test strip method in parturients with normal and abnormal cardiotocograms during labour and to describe the relation to maternal lactate, fetal scalp blood pH, cord artery lactate and acid-base balance. SETTING: Labour wards at the University Hospitals of Huddinge and ...

The present study was designed to see if lactate can cross the blood-brain barrier of the near-term fetal sheep and replace glucose as an oxidative substrate during normoglycemia and acute insulin-induced hypoglycemia. Cerebral uptake of glucose, oxygen, lactate, and [14C]lactate as well as cerebral production of 14CO2 were measured under ...

A low cost microprocessor-based system for continuous in-vivo measurement of blood pH and pCO2 using a biosensor is being developed. The biosensor is a pH Ti2O3 ISFET (Ion Sensitive Field Effect Transistor) with a sensitivity of -56 mV/pH and a linear response over physiologically meaningful blood pH range of 6.5 ...

OBJECTIVE: To investigate the venous-arterial PCO2 gradient, and the mixed venous blood acid-base status together with the oxygen transport variables in a group of acutely ill postsurgical patients. DESIGN: Retrospective, descriptive study of hemodynamic and acid-base data collected immediately after the patients' admission to the Postsurgical Intensive Care Unit. SETTING: ...

Evaluation of a portable blood gas analyzer, (StatPal II, Unifet, Inc, La Jolla, CA) was performed using tonometered solutions and equine blood. Samples were analyzed by the StatPal II and either an Instrument Laboratory IL1306 (Lexington, MA) or a Radiometer ABL50 blood gas analyzer (Radiometer America Inc., Westlake, OH). Comparison ...

Lactate, pyruvate, beta-hydroxybutyrate, and acetoacetate are intermediary metabolites normally occurring in blood. Their relative concentrations are an expression of nutritional balance in energy metabolism. The simultaneous determination of these four analytes is of special interest in the understanding of energy homeostasis. Rapid, precise routine measurement of these four analytes is ...

To examine factors determining the haemodynamic and metabolic responses to treatment of diabetic ketoacidosis with alkali, groups of anaesthetised and ventilated rats with either diabetic ketoacidosis (mean arterial pH 6.86-6.96, mean arterial blood pressure 63-67 mm Hg) or hypovolaemic shock due to blood withdrawal (mean pHa 7.25-7.27, mean arterial blood ...

The effects of adding Carbicarb--a 50:50 mixture of sodium bicarbonate (NaHCO3) and sodium carbonate (Na2CO3)--or sodium bicarbonate or disodium carbonate individually to whole blood were examined in vitro. Adding HCl to blood in an open system rapidly decreased the pH and [HCO3-] without increasing partial pressure of carbon dioxide (PCO2), ...

Recently developed biosensor technology, which allows near real-time measurement in situ of gas tension (pCO2 and pO2) and of pH, was applied to arterial blood, cerebrospinal fluid (CSF), and brain parenchyma during intravenous lactate infusion in monkeys. Comparison of simultaneous biosensor measurements and discrete arterial blood sampling for traditional blood ...

We investigated the in vivo changes in cerebral energy metabolism and pHi in newborn mice noninvasively during 8 h of hypoxia with FiO2 = 5%, using phosphorus magnetic resonance spectroscopy continuously. The intracellular brain pH (pHi) increased from 7.20 +/- 0.03 to 7.36 +/- 0.03 (P < 0.05) at 1 ...

For the purpose of demonstrating both the clinical value and economic advantages of using blood lactate as a marker for haemodynamic instability, we present the clinical guidelines for when to measure blood lactate and how these measurements are interpreted in two clinical settings: following open-heart surgery for complex congenital heart ...

BACKGROUND: Because our laboratory had used the Ciba Corning 200 series blood-gas analyzers for a number of years, we were asked to participate in the evaluation of a premarket unit of the Model 840 analyzer (C840). DESCRIPTION OF DEVICE: The C840 is a bench-top instrument that combines a menu-driven user ...