Lactate concentrations monitoring

Routine monitoring of lactate is not recommended, since lactate concentrations do not correlate with symptoms and patients may have asymptomatic lactatemia. Furthermore, technical difficulties in blood collection and processing, and the lack of a standardized definition of lactic acidosis for patients taking NRTIs, prevent any routine monitoring recommendations in the absence of symptoms. In addition, it is possible that NRTIs also cause other forms of mitochondrial dysfunction. 

Ozturk SS, Thrift JC, Blackie JD, Naveh D (1997), Real-time monitoring and control of glucose and lactate concentrations in a mammalian cell perfusion reactor, Biotechnol. Bioeng. 53 372-378. 

Laboratory tests indicated for the ongoing monitoring of shock include electrolytes and renal function tests (blood urea nitrogen, serum creatinine) complete blood count to assess possible infection, 02-carrying capacity of the blood, and ongoing bleeding PT and aPTT to assess clotting ability and lactate concentration and base deficit to detect inadequate tissue perfusion. 

The oxidation reaction of lactate in the presence of LOx at 23°C and 37°C was completed in 10s to 4 min, depending, as expected, on the LOx and lactate concentrations. Despite the relatively long time needed for completion of the oxidation reaction at low enzyme concentrations, a calibration curve for a given film can be obtained at shorter times by monitoring t after a constant reaction time for different analyte concentrations. A calibration curve can be obtained also by plotting the initial rate of change of t, (dr/dtjo, which is related to the initial reaction rate, vs. lactate concentration. Such a calibration... 

Figure 3.19 shows a calibration curve of 1/t at the completion of the reaction (<30s) vs. lactate concentration (see Eq. (3.4)) using 7.5 units mL stabilized enzyme. As shown below, this type of linear calibration curve was adopted for monitoring analyte mixtures. 

Rapid sampling on-line biosensor system was used for monitoring of intramural glucose and lactate concentrations from the dialysate of a microdialysis probe tunneled in the seromuscular layer of seven patient left colon and in a different study in a peri-anastomotic segment in 5 colo-colic stapled anastomosis in a swine model. 

Figure 14.12 Monitoring of lactate concentration and the change of cell metabolic activity after stimulation by fetal bovine serum (FBS) (Boubriak et al., 2006a).

In a review of data on occupational chemicals that may contaminate breast milk (Byczkowski et al. 1994), it is stated that lead may be excreted in milk in amounts lethal to the infant and that the metal may be mobilized from bone stores to milk during the lactation period. Even when the concentration of lead in mother s milk is low, the absorption of metals into the systemic circulation of infants is generally high when they are on a milk diet. To better understand the sensitivity of the nursing infant to chemicals, epidemiological studies, chemical monitoring, and model development and application are needed. 

Polybrominated Diphenyl Ethers. PBDEs also accumulate in adipose tissue, serum, and breast milk of the general population due to their lipophilic characteristics. Concentrations of PBDEs in breast milk are useful, non-invasive markers of maternal body burdens and of in utero and lactational exposures, but body burden assessments are limited by a lack of time-trend data for PBDEs in tlie milk of U.S. populations (Hooper and McDonald 2000). Breast milk monitoring programs are needed to provide time-trend data and to verify findings that PBDE levels have been exponentially increasing in breast milk during the past 25 years (Noren and Meironyte 1998, 2000). Studies on the predictive value of levels of PBDEs in scrum and adipose tissue could provide useful infonnation for detection and monitoring of exposure. 

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