scholarly journals Investigations into the Effects of pH on Quantitative Measurements of Lactate in Biological Media Using ATR-FTIR Spectroscopy

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3695
Author(s):  
Nystha Baishya ◽  
Mohammad Mamouei ◽  
Karthik Budidha ◽  
Meha Qassem ◽  
Pankaj Vadgama ◽  
...  
Keyword(s):  
Biochemical Marker ◽  
Lactate Concentration ◽  
Spectral Features ◽  
Cell Respiration ◽  
Biological Media ◽  
Quantitative Measurements ◽  
Lactate Measurement ◽  
Effects Of Ph ◽  
Concentration Changes ◽  
Potential Tool

Quantification of lactate/lactic acid in critical care environments is essential as lactate serves as an important biochemical marker for the adequacy of the haemodynamic circulation in shock and of cell respiration at the onset of sepsis/septic shock. Hence, in this study, ATR-FTIR was explored as a potential tool for lactate measurement, as the current techniques depend on sample preparation and fails to provide rapid response. Moreover, the effects of pH on PBS samples (7.4, 7, 6.5 and 6) and change in solution conditions (PBS to whole blood) on spectral features were also investigated. A total 189 spectra from five sets of lactate containing media were obtained. Results suggests that lactate could be measured with more than 90% accuracy in the wavenumber range of 1500–600 cm−1. The findings of this study further suggest that there exist no effects of change in pH or media, when estimating lactate concentration changes in this range of the Mid-IR spectral region.

scholarly journals A multidisciplinary approach to overreaching detection in endurance trained athletes

2013 ◽  
Vol 114 (3) ◽  
pp. 411-420 ◽  
Author(s):  
Yann Le Meur ◽  
Christophe Hausswirth ◽  
Françoise Natta ◽  
Antoine Couturier ◽  
Frank Bignet ◽  
...  
Keyword(s):  
Heart Rate ◽  
Multidisciplinary Approach ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Peak Performance ◽  
Impaired Performance ◽  
Classification Score ◽  
Concentration Changes ◽  
Biomechanical Parameters ◽  
Running Pattern

In sport, high training load required to reach peak performance pushes human adaptation to their limits. In that process, athletes may experience general fatigue, impaired performance, and may be identified as overreached (OR). When this state lasts for several months, an overtraining syndrome is diagnosed (OT). Until now, no variable per se can detect OR, a requirement to prevent the transition from OR to OT. It encouraged us to further investigate OR using a multivariate approach, including physiological, biomechanical, cognitive, and perceptive monitoring. Twenty-four highly trained triathletes were separated into an overload group and a normo-trained group (NT) during 3 wk of training. Given the decrement of their running performance, 11 triathletes were diagnosed as OR after this period. A discriminant analysis showed that the changes of eight parameters measured during a maximal incremental test could explain 98.2% of the OR state (lactatemia, heart rate, biomechanical parameters and effort perception). Variations in heart rate and lactatemia were the two most discriminating factors. When the multifactorial analysis was restricted to these variables, the classification score reached 89.5%. Catecholamines and creatine kinase concentrations at rest did not change significantly in both groups. Running pattern was preserved and cognitive performance decrement was observed only at exhaustion in OR subjects. This study showed that monitoring various variables is required to prevent the transition between NT and OR. It emphasized that an OR index, which combines heart rate and blood lactate concentration changes after a strenuous training period, could be helpful to routinely detect OR.

Erythrocyte ion regulation across inactive muscle during leg exercise

1992 ◽  
Vol 70 (12) ◽  
pp. 1625-1633 ◽  
Author(s):  
R. S. McKelvie ◽  
M. I. Lindinger ◽  
N. L. Jones ◽  
G. J. F. Heigenhauser
Keyword(s):  
Intermittent Exercise ◽  
Lactate Concentration ◽  
Cycle Ergometer ◽  
Ion Concentration ◽  
Ion Regulation ◽  
Exercise Period ◽  
Leg Exercise ◽  
Concentration Changes ◽  
Active Transport System ◽  
Venous Plasma

Ion concentration changes in whole blood, plasma, and erythrocytes across inactive muscle were examined in eight healthy males performing four 30-s bouts of maximal isokinetic cycling with 4 min rest between each bout. Blood was sampled from the arm brachial artery and deep antecubital vein during the intermittent exercise period and for 90 min of recovery. Arterial and venous erythrocyte lactate concentration ([Lac−]) increased from 0.3 ± 0.1 to 12.5 ± 1.3 (p < 0.01) and 1.1 ± 0.4 to 8.5 ± 1.5 mmol/L (p < 0.01), respectively, returning to control values during recovery. Arterial and venous plasma [Lac−] increased from 1.5 ± 0.2 to 27.7 ± 1.8 and from 1.3 ± 0.4 to 25.7 ± 3.5 mmol/L, respectively, and was greater than erythrocyte [Lac−] throughout exercise and recovery. Arterial and venous [K+] increased in erythrocytes from 119.5 ± 5.1 to 125.4 ± 4.6 (p < 0.01) and from 113.6 ± 1.7 to 120.6 ± 7.1 mmol/L, respectively, decreasing to control during recovery. In arterial and venous plasma, [K+] increased from 4.3 ± 0.1 to 6.1 ± 0.2 (p < 0.01) and from 4.5 ± 0.2 to 5.3 ± 0.2 mmol/L (p < 0.01), respectively, decreasing to control during recovery. The efflux of Lac− out of erythrocytes against an electrochemical concentration gradient suggests the presence of an active transport system. Efflux of K+ from erythrocytes as blood passes across inactive muscle affords an important adaptation to the K+ release from muscle activated in heavy exercise.Key words: isokinetic cycle ergometer, potassium, lactate, red cell volume, arteriovenous difference.

Regulation of lactate uptake and lactate production in liver from 48-h-starved rats: Effects of pH, flow and glucose concentration

1988 ◽  
Vol 74 (4) ◽  
pp. 403-406 ◽  
Author(s):  
Leif Sestoft ◽  
Michael O. Marshall
Keyword(s):  
Glucose Concentration ◽  
Lactate Concentration ◽  
Lactate Production ◽  
Low Ph ◽  
Low Flow ◽  
Normal Flow ◽  
Ph Values ◽  
Effects Of Ph ◽  
Inhibition Of Glycolysis ◽  
Lactate Uptake

1. The effects of medium glucose concentration (0–20 mmol/l) and flow (100–33% of normal) on lactate uptake at low lactate concentration were studied in perfused livers from 48-h-starved rats with perfusate pH values of 7.4 and 6.8. 2. Lactate uptake was independent of glucose concentration in the range 5–10 mmol/l, but was slightly inhibited with time at 20 mmol/l glucose. This pattern was independent of perfusate pH. 3. At both pH values lactate uptake decreased proportionally with flow, and at low flow lactate was produced by the livers. The effect of flow was greatest at pH 7.4 where a net lactate production was found at 48% of normal flow, whereas at pH 6.8 lactate production was not seen until the flow was reduced to 33% of normal. 4. When glucose was omitted from the perfusate lactate production ceased at both pH values. 5. The effect of low pH on lactate uptake and production in liver probably reflects inhibition of glycolysis by low pH.

scholarly journals Computational modelling of the piglet brain to simulate near-infrared spectroscopy and magnetic resonance spectroscopy data collected during oxygen deprivation

2012 ◽  
Vol 9 (72) ◽  
pp. 1499-1509 ◽  
Author(s):  
Tracy Moroz ◽  
Murad Banaji ◽  
Nicola J. Robertson ◽  
Chris E. Cooper ◽  
Ilias Tachtsidis
Keyword(s):  
Infrared Spectroscopy ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Redox State ◽  
Near Infrared ◽  
Lactate Concentration ◽  
Computational Modelling ◽  
Resonance Spectroscopy ◽  
Concentration Changes

We describe a computational model to simulate measurements from near-infrared spectroscopy (NIRS) and magnetic resonance spectroscopy (MRS) in the piglet brain. Piglets are often subjected to anoxic, hypoxic and ischaemic insults, as experimental models for human neonates. The model aims to help interpret measurements and increase understanding of physiological processes occurring during such insults. It is an extension of a previous model of circulation and mitochondrial metabolism. This was developed to predict NIRS measurements in the brains of healthy adults i.e. concentration changes of oxyhaemoglobin and deoxyhaemoglobin and redox state changes of cytochrome c oxidase (CCO). We altered and enhanced the model to apply to the anaesthetized piglet brain. It now includes metabolites measured by 31 P-MRS, namely phosphocreatine, inorganic phosphate and adenosine triphosphate (ATP). It also includes simple descriptions of glycolysis, lactate dynamics and the tricarboxylic acid (TCA) cycle. The model is described, and its simulations compared with existing measurements from piglets during anoxia. The NIRS and MRS measurements are predicted well, although this requires a reduction in blood pressure autoregulation. Predictions of the cerebral metabolic rate of oxygen consumption (CMRO 2 ) and lactate concentration, which were not measured, are given. Finally, the model is used to investigate hypotheses regarding changes in CCO redox state during anoxia.

Phenylbutazone increases right atrial pressure and heart rate of running horses

1996 ◽  
Vol 81 (1) ◽  
pp. 312-317 ◽  
Author(s):  
L. A. Mitten ◽  
K. W. Hinchcliff ◽  
J. L. Pate
Keyword(s):  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Right Atrial ◽  
Co2 Production ◽  
Detectable Effect ◽  
O2 Consumption ◽  
Venous Compliance ◽  
Cyclooxygenase Activity ◽  
Pulmonary Arterial ◽  
Concentration Changes

The effect of inhibition of cyclooxygenase activity on the hemodynamic response to exertion was examined in 6 horses. Rates of O2 consumption and CO2 production and carotid, pulmonary arterial, and right atrial pressures were measured while the horses performed a standardized exercise test on a treadmill after treatment with phenylbutazone or a placebo. Phenylbutazone (8.8 mg/kg p.o. for 2 days and 4.4 mg/kg i.v. 60 min before exertion) abolished the exertion-induced increases in plasma 6-ketoprostaglandin F1 alpha and thromboxane B2 concentrations, confirming inhibition of cyclooxygenase activity. Phenylbutazone treatment resulted in significantly (P < 0.05) higher heart rates and right atrial pressures during exertion than did treatment with placebo, which may have been due to increased myocardial sensitivity to sympathetic stimulation and/or decreased venous compliance. There was not a detectable effect of phenylbutazone on carotid or pulmonary arterial pressures, O2 consumption, CO2 production, or blood lactate concentration. Changes in plasma volume during exertion were not influenced by phenylbutazone. These results demonstrate that cyclooxygenase products likely mediate or modulate some of the systemic hemodynamic responses to exertion in horses.

scholarly journals Near infrared spectrometric investigation of lactate in a varying pH buffer

2020 ◽  
Vol 28 (5-6) ◽  
pp. 328-333 ◽  
Author(s):  
Nystha Baishya ◽  
Mohammad Momouei ◽  
Karthik Budidha ◽  
Meha Qassem ◽  
Pankaj Vadgama ◽  
...  
Keyword(s):  
Critical Care ◽  
Lactic Acidosis ◽  
Water Absorption ◽  
Near Infrared ◽  
Ph Monitoring ◽  
Lactate Concentration ◽  
Concentration Changes ◽  
Lactate Levels ◽  
Continuous Technology

Lactic acidosis is commonly observed in various disease states in critical care and can be adopted as a hemodynamic biomarker, as well as a target for therapy. pH is the main biomarker for the diagnosis of acid–base disorders and is currently measured utilizing invasive blood sampling techniques. Therefore, there is a need for a non-invasive and continuous technology for the measurement of pH and lactate levels. In this work, near infrared spectroscopy is explored as a technique for investigating lactic acidosis. In-vitro studies on 20 isotonic phosphate buffer solutions of varying pH with constant lactate concentration (2 mmol/L) were performed. The whole near infrared spectrum (800–2600 nm) was then divided into four parts for analysis: (a) water absorption peaks, (b) 1000–1250 nm, (c) 1700–1760 nm, and (d) 2200–2400 nm. The water absorption peaks showed a linear variation with the changes in pH in the spectra. The range from 1700–1760 nm showed good correlation with calculated values for lactate ionization, with the changes in pH. However, the region from 2200–2400 nm showed a reverse correlation with respect to the concentration changes of lactate and a distinction could be made from pH 6–7 and 7–8. This study successfully identifies wavelengths (1233 nm, 1710 nm, 1750 nm, 2205 nm, 2319 nm, and 2341 nm) which can be directly correlated to lactic acidosis. Knowledge from this study will contribute toward the development of lactate-based pH monitoring optical sensor for critical care.

scholarly journals Blood lactate accumulation and muscle deoxygenation during incremental exercise

1999 ◽  
Vol 87 (1) ◽  
pp. 348-355 ◽  
Author(s):  
Bruno Grassi ◽  
Valentina Quaresima ◽  
Claudio Marconi ◽  
Marco Ferrari ◽  
Paolo Cerretelli
Keyword(s):  
Blood Lactate ◽  
Continuous Wave ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Incremental Exercise ◽  
Vastus Lateralis Muscle ◽  
Lactate Accumulation ◽  
Muscle Deoxygenation ◽  
Blood Lactate Accumulation ◽  
Concentration Changes

Near-infrared spectroscopy (NIRS) could allow insights into controversial issues related to blood lactate concentration ([La]b) increases at submaximal workloads (w˙). We combined, on five well-trained subjects [mountain climbers; peak O2 consumption (V˙o 2peak), 51.0 ± 4.2 (SD) ml ⋅ kg−1 ⋅ min−1] performing incremental exercise on a cycle ergometer (30 W added every 4 min up to voluntary exhaustion), measurements of pulmonary gas exchange and earlobe [La]b with determinations of concentration changes of oxygenated Hb (Δ[O2Hb]) and deoxygenated Hb (Δ[HHb]) in the vastus lateralis muscle, by continuous-wave NIRS. A “point of inflection” of [La]b vs.w˙ was arbitrarily identified at the lowest [La]b value which was >0.5 mM lower than that obtained at the following w˙. Total Hb volume (Δ[O2Hb + HHb]) in the muscle region of interest increased as a function ofw˙ up to 60–65% ofV˙o 2 peak, after which it remained unchanged. The oxygenation index (Δ[O2Hb − HHb]) showed an accelerated decrease from 60– 65% ofV˙o 2 peak. In the presence of a constant total Hb volume, the observed Δ[O2Hb − HHb] decrease indicates muscle deoxygenation (i.e., mainly capillary-venular Hb desaturation). The onset of muscle deoxygenation was significantly correlated ( r 2 = 0.95; P < 0.01) with the point of inflection of [La]bvs. w˙, i.e., with the onset of blood lactate accumulation. Previous studies showed relatively constant femoral venous[Formula: see text] levels at w˙ higher than ∼60% of maximal O2consumption. Thus muscle deoxygenation observed in the present study from 60–65% ofV˙o 2 peak could be attributed to capillary-venular Hb desaturation in the presence of relatively constant capillary-venular[Formula: see text] levels, as a consequence of a rightward shift of the O2Hb dissociation curve determined by the onset of lactic acidosis.

scholarly journals Quantitative Two-Dimensional Classifications of Low Dispersion Objective Prism Spectra

1978 ◽  
Vol 80 ◽  
pp. 29-32
Author(s):  
Th. Schmidt-Kaler
Keyword(s):  
List Type ◽  
Spectral Features ◽  
Two Dimensional ◽  
Type Number ◽  
Comparison Spectrum ◽  
Stellar Spectra ◽  
Quantitative Measurements ◽  
Light Losses ◽  
Objective Prism ◽  
Low Dispersion

The objective prism (or grating) is the most efficient stellar spectrograph since it suffers no light losses at a slit and - compared to a slit spectrograph - only small losses in the camera optics. However, objective prism spectra have two principal disadvantages:(1)the spectral resolution (and consequently the sharpness of spectral features) depends on the seeing, which may vary from plate to plate.(2)quantitative measurements are difficult because of the difficulty in obtaining an exact photographic calibration; no comparison spectrum can be placed near the stellar spectra.

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