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PubMed2000

Nanomolar concentrations of inorganic lead increase Ca2+ efflux and decrease intracellular free Ca2+ ion concentrations in cultured rat hippocampal neurons by a calmodulin-dependent mechanism.

Inorganic lead (Pb2+) activates calmodulin, which in turn may stimulate many other cellular processes. The plasma membrane Ca2+ ATPase is a calmodulin-stimulated enzyme that plays the major role in regulating the "resting" intracellular free Ca2+ ion concentration, [Ca2+]i. We hypothesized that exposing neurons to low levels of Pb2+ would cause Pb2+ to enter the cytoplasm, and that intracellular Pb2+, by activating calmodulin, would stimulate plasma membrane Ca2+ ATPase activity, thereby increasing Ca2+ extrusion and reducing [Ca2+]i. We used the ratiometric Ca2+ indicator fura-2 to estimate changes in [Ca2+]i. In vitro calibrations of fura-2 with solutions of defined free Ca2+ and free Pb2+ concentrations showed that, at free Ca2+ concentrations from 10 nM to 1000 nM, adding Pb2+ caused either no significant change in the F340/F380 ratio (free Pb2+ concentrations from 100 fM to 1 pM) or increased the F340/F380 ratio (free Pb2+ concentrations from 5 to 50 pM). Therefore, fura-2 should be suitable for estimating Pb2+-induced decreases in [Ca2+]i, but not increases in [Ca2+]i. We exposed cultured embryonic rat hippocampal neurons to 100 nM Pb2+ for periods from 1 hour to 2 days and measured the F340/F380 ratio; the ratio decreased significantly by 9 to 16% at all time points, indicating that Pb2+ exposure decreased [Ca2+]i. In neurons loaded with 45Ca, Pb2+ exposure increased Ca2+ efflux for at least two hours; by 24 hours, Ca2+ efflux returned to control levels. Influx of 45Ca was not altered by Pb2+ exposure. Low concentrations (250 nM) of the calmodulin inhibitor calmidazolium had no effect on either 45Ca efflux or on the F340/F380 ratio in fura-loaded control neurons, but completely eliminated the increase in 45Ca efflux and decrease in F340/F380 ratio in Pb2+-exposed neurons. Zaldoride, another calmodulin inhibitor, also eliminated the decrease in F340/F380 ratio in Pb2+-exposed neurons. We conclude that Pb2+ exposure decreases [Ca2+]i and increases Ca2+ efflux in cultured hippocampal neurons by a calmodulin-dependent mechanism, probably by stimulating Ca2+ extrusion by the plasma membrane Ca2+ ATPase.

Animals↗

PubMed2000

Lipid and apolipoprotein concentrations in prenodal leg lymph of fasted humans. Associations with plasma concentrations in normal subjects, lipoprotein lipase deficiency, and LCAT deficiency.

The extent to which lipid and apolipoprotein (apo) concentrations in tissue fluids are determined by those in plasma in normal humans is not known, as all studies to date have been performed on small numbers of subjects, often with dyslipidemia or lymphedema. Therefore, we quantified lipids, apolipoproteins, high density lipoprotein (HDL) lipids, and non-HDL lipids in prenodal leg lymph from 37 fasted ambulant healthy men. Lymph contained almost no triglycerides, but had higher concentrations of free glycerol than plasma. Unesterified cholesterol (UC), cholesteryl ester (CE), phosphatidylcholine (PC), and sphingomyelin (SPM) concentrations in whole lymph were not significantly correlated with those in plasma. HDL lipids, but not non-HDL lipids, were directly related to those in plasma. Lymph HDLs were enriched in UC. However, as the HDL cholesterol/non-HDL cholesterol ratio in lymph exceeded that in plasma, whole lymph nevertheless had a lower UC/CE ratio than plasma. Lymph also had a significantly higher SPM/PC ratio. The lymph/plasma (L/P) ratios of apolipoproteins were as follows: A-IV > A-I and A-II > C-III and E > B. Comparison with the L/P ratios of seven nonlipoprotein proteins suggested that apoA-IV was predominantly lipid free. Concentrations of apolipoproteins A-II, A-IV, C-III, and E in lymph, but not of apolipoproteins A-I or B, were positively correlated with those in plasma. The L/P ratios of apolipoproteins B, C-III, and E in two subjects with lipoprotein lipase (LPL) deficiency, and of apolipoproteins A-I and A-IV in a subject with lecithin:cholesterol acyltransferase (LCAT) deficiency, were low relative to those in normal subjects. Thus, the concentrations of lipids, apolipoproteins, and lipoproteins in human tissue fluid are determined only in part by their concentrations in plasma. Other factors, including the actions of LPL and LCAT, are at least as important.

Adult↗

PubMed2001

A general best-fit method for concentration-response curves and the estimation of low-effect concentrations.

Risk assessments of toxic chemicals currently rely heavily on the use of no-observed-effect concentrations (NOECs). Due to several crucial flaws in this concept, however, discussion of replacing NOECs with statistically estimated low-effect concentrations continues. This paper describes a general best-fit method for the estimation of effects and effect concentrations by the use of a pool of 10 different sigmoidal regression functions for continuous toxicity data. Due to heterogeneous variabilities in replicated data (i.e., heteroscedasticity), the concept of generalized least squares is used for the estimation of the model parameters, whereas a nonparametric variance model based on smoothing spline functions is used to describe the heteroscedasticity. To protect the estimates against outliers, the generalized least-squares method is improved by winsorization. On the basis of statistical selection criteria, the best-fit model is chosen individually for each set of data. Furthermore, the bootstrap methodology is applied for constructing confidence intervals for the estimated effect concentrations. The best-fit method for the estimation of low-effect concentrations is validated by a simulation study, and its applicability is demonstrated with toxicity data for 64 chemicals tested in an algal and a bacterial bioassay. In comparison with common methods of concentration-response analysis, a clear improvement is achieved.

Data Interpretation, Statistical↗

PubMed1976

The mechanism of hypergastrinemia in achlorhydria. Effect of food, acid, and calcitonin on serum gastrin concentrations and component pattern in pernicious anemia, with correlation to endogenous secretin concentrations in plasma.

The effect of protein-rich food, intravenous calcitonin injections, and intragastric instillation of hydrochloric acid on serum gastrin concentrations and gastrin component pattern was studied in hypergastrinemic patients (pernicious anemia) and matched control subjects. Moreover, plasma secretin concentrations were measured during intragastric acidification. The intragastric acidification resulted in rapid fall in serum gastrin concentrations, although not below the upper limit of normal range. The small components, III (gastrin-17-like) and IV (gastrin-13-like), almost disappeared, whereas the concentrations of component I and component II (gastrin-34-like) were less affected. The increase in secretin concentrations after intragastric acidification was smaller in patients with pernicious anemia than in normal subjects, although the difference was not significant. In contrast to the results in normal control subjects, neither food nor calcitonin produced significant variations in serum gastrin concentrations and gastrin component pattern of pernicious anemia patients. The failure of food to stimulate and of calcitonin to inhibit release of gastrin in the majority of pernicious anemia patients might suggest that gastrin secretion in these patients is autonomous. However, considering the recently recognized slow metabolic clearance rate of big gastrins, the effect of intragastric acidification suggests that the mechanism for acid inhibition of the antral gastrin secretion is intact in patients with achlorhydria.

Achlorhydria↗

PubMed1989

[Concentration of lipids in ascitic fluid and the concentration gradient of albumin in blood and ascites: diagnostic significance].

The aim of this study was to test the diagnostic value of ascitic fluid cholesterol and triglycerides concentrations and of serum-ascites albumin concentration gradient in the differentiation between cirrhotic and malignant ascites. These biological parameters were determined, on the one hand in 34 cirrhotic patients, 6 of them having an hepatocellular carcinoma and 6 others having a spontaneous bacterial peritonitis and, on the other hand, in 16 patients with malignant ascites, 13 of them having an abdominal extra-hepatic or pelvic cancer, and 3 others having an extra-abdominal cancer with multiple liver metastases. Ascitic carcinoembryonic antigen assay and ascitic fluid cytology were also done in the 50 patients. In differentiating the cirrhotic patients from those with malignancy, ascitic fluid cholesterol concentration (discriminating value less than 1.1 mmol/l) ascitic fluid triglycerides concentration (discriminating value 0.5 mmol/l) and serum-ascites albumin concentration gradient (discriminating value greater than 11 g/l) allowed a diagnostic efficiency of 0.92, 0.80 and 0.77, respectively. Ascitic fluid cytology showed presence of malignant cells in 3/6 patients with hepatocellular carcinoma associated with cirrhosis, in 9/16 patients having a malignant ascites, and was negative in other patients. Ascitic carcinoembryonic antigen assay was abnormal only in 3/16 patients with malignant ascites. These results suggest that measurement of ascitic fluid cholesterol concentration must be included in the initial evaluation of patients with ascites of unknown origin.

Albumins↗

PubMed1988

[Minimum inhibitory concentration and minimum bactericidal concentration of tetracycline and erythromycin in 35 recent Munich isolates of Chlamydia trachomatis].

Thirty-five recent clinical isolates of Chlamydia trachomatis were subcultured and subjected to antimicrobial susceptibility testing with tetracycline and erythromycin. Detection of typical chlamydial inclusion bodies and elementary bodies was based on the use of fluorescence-labelled monoclonal antibodies. Minimum inhibitory concentration being defined as the lowest concentration suppressing all inclusion body formation and minimum bactericidal concentration as the lowest concentration preventing all detectable chlamydial growth, both these parameters were studied. With tetracycline the minimum inhibitory concentrations ranged from 0.03 to 0.08 microgram/ml, with erythromycin from 0.04 to 0.2 microgram/ml. The corresponding data for the minimum bactericidal concentrations were less than 0.2 to 1.0 and 0.2 to 2.0 respectively. Thus, at present, there still seems to be no major resistance problem with genital Chlamydia trachomatis isolates in the Federal Republic of Germany.

Chlamydia trachomatis↗

PubMed1994

Tocopherol concentrations in adipose tissue. Relationships of tocopherol concentrations and fatty acid composition in serum in a reference population of Swedish men and women.

The tocopherol concentrations in serum and adipose tissue were studied in relation to the fatty acid composition and clinical characteristics in 110 subjects. The tocopherol concentrations in adipose tissue showed large interindividual variations and were positively correlated to those in serum (r = 0.24-0.31, P < 0.01) but did not increase with age. The ratio between alpha- and gamma-tocopherol in adipose tissue was only about half of that in serum. In serum, but not in adipose tissue, the alpha-tocopherol and linoleic acid concentrations were positively correlated. Serum apolipoprotein B was inversely correlated to lipid-corrected serum alpha-tocopherol (r = -0.22, P = 0.03), indicating decreasing oxidative protection with increasing blood lipids. Measurement of the serum tocopherol concentration in addition to that of the serum lipoprotein concentration may be of value in estimating the risk for coronary heart disease. Whether measurement of the tocopherol concentration in adipose tissue has any advantage over that in serum remains to be determined.

Adipose Tissue↗

PubMed1993

In vitro evaluation of factor VIII--bypassing activity of activated prothrombin complex concentrate, prothrombin complex concentrate, and factor VIIa in the plasma of patients with factor VIII inhibitors: thrombin generation test in the presence of collagen-activated platelets.

Clinical efficacy of plasma-derived products with factor VIII--bypassing activity in patients with factor VIII inhibitors is difficult to evaluate. It is also difficult to predict efficacy by coagulation assay. A test of thrombin generation in defibrinated plasma and in the presence of activated platelets was used to test the bypassing activity of the most currently used products (activated prothrombin complex concentrate from various origins, prothrombin complex concentrate, and factor VIIa). The bypassing activity was evaluated in the absence and presence of tissue factor. In plasma with inhibitor, activated prothrombin complex concentrate elicited dose-dependent thrombin formation, whereas prothrombin complex concentrate and factor VIIa induced only minimal thrombin activity. Addition of tissue factor in the assay elicited thrombin generation in the presence of factor VIIa and prothrombin complex concentrate and allowed additional thrombin formation in the presence of activated prothrombin complex concentrate. Although it is hazardous to extend results of in vitro testing to clinical efficacy, our study sheds some light on the mechanism of action of the various substances used to treat bleeding episodes in patients with factor VIII inhibitors.

Blood Coagulation Factors↗

PubMed1995

Diurnal cycle of SO2 concentrations in Rijeka and its relation to maximum and average daily concentrations.

Continuous recording of SO2 concentrations at one site in Rijeka in the heating season has shown that in spite of geographic and climatic differences, the pattern of diurnal cycle of SO2 concentrations does not differ from that recorded in Zagreb and in other towns with a temperate climate. The pattern is characterized by two peaks: a higher one in the morning that represents daily maximum and a lower one in the afternoon that is a good approximation of daily mean. Accordingly, maximum and mean daily concentrations could be assessed by short-term samples collected over given periods (8-10 and 15-18 h). As the diurnal cycle of SO2 concentrations could be disturbed by changes in weather conditions, equations were developed and coefficients established for calculating correction factors for adjustment of the estimated daily maximum and mean concentrations from two samples of short duration. The equations developed in Zagreb proved to be also valid for Rijeka. Presumably, the procedure could be used in other towns in the temperate region after the pattern of diurnal cycle of SO2 concentrations has been verified and the coefficients necessary for calculating correction factors established.

Air Pollutants↗

PubMed1996

[Rheological behavior of tomato concentrates: effect of temperature and concentration].

The rheological properties of various brands of double concentrated tomato paste manufactured in Venezuela were studied. The effect of temperature (30, 40, 50, 60 degrees C) and concentration (15, 20, 25 and 30% total solids) was determined. A concentric cylinders viscometer Haake Rotovisco RV-2 was used for this purpose. A psudoplastic behaviour that followed the power law was found. The rheological parameters (consistency and behavior indexes) that characterize each paste were determined for the conditions of the study. According to the statistical analyses done the consistency index (K) diminished with an increase in temperature and increased as the concentration increased. An equation to determine the consistency index as a function of temperature and concentration was obtained. Likewise, it was found that temperature did not have a significant effect on the behavior index (n) in the range from 30 to 50 degrees C, however this effect was significant for some of the pastes at 60 degrees C. On the other hand, concentration levels above 20% total solids did not have a significant effect on the behavior index, but a significant effect was determined for 15% total solids.

Solanum lycopersicum↗

PubMed1976

Concentration of MgATP2- and other ions in solution. Calculation of the true concentrations of species present in mixtures of associating ions.

1. A simple method is described for calculating the free concentrations of all species in a mixture of several ionic components that associate at equilibrium to any extent and with any stoicheiometry. 2. It can readily be adapted to take account of species such as protons for which the free rather than the total concentrations are controlled. 3. It was applied to mixtures of adenine nucleotides, Mg2+ and other ions relevant to the study of glucokinase (EC 2.7.1.2), but the qualitative conclusions are not peculiar to this system. 4. ATP exists in a high and nearly constant proportion (about 80%) as MgATP2- in solutions in which the total MgCl2 concentration exceeds the total ATP concentration by 1-10 mM. 5. By contrast, the proportion of ATP present as MgATP2- varies greatly if the total MgCl2 and total ATP concentrations are varied in constant proportion.

Adenosine Triphosphate↗

PubMed1989

Influence of flow rate, pH and plasma fluoride concentrations on fluoride concentration in human parotid saliva.

In two separate studies the influence of some physiological factors on salivary fluoride excretion was investigated. In the first study, parotid saliva, at two predetermined flow rates, and capillary blood were sampled after ingestion of 1 mg fluoride. In the second study, parotid saliva was collected at five different flow rates, starting 1 h after ingestion of 5 mg fluoride. Capillary blood was sampled throughout the experiment. The first study showed that parotid saliva and plasma fluoride concentrations were closely correlated (r = 0.81). The mean parotid salivary and plasma fluoride concentration ratio (S/P ratio) +/- SD ranged from 0.29 +/- 0.11 to 0.65 +/- 0.15. The fractions of the ingested fluoride dose excreted from one parotid gland were 0.08 and 0.18% at flow rates of 0.25 +/- 0.02 and 0.49 +/- 0.06 ml/min, respectively. The second study showed that at the mean basal plasma fluoride concentration of 0.65 +/- 0.18 mumol/l the mean S/P ratio was 0.55 +/- 0.24. At a plasma fluoride concentration ranging from 3.5 to 11.6 mumol/l the S/P ratio was 0.73 +/- 0.15. Thus the S/P ratio was influenced by the plasma fluoride concentration, but not by variations in parotid salivary flow rate or pH.

Adult↗

PubMed2004

Sedimentation equilibrium in a solution containing an arbitrary number of solute species at arbitrary concentrations: theory and application to concentrated solutions of ribonuclease.

Simple expressions are derived describing the equilibrium concentration gradient of each species in a solution containing an arbitrary number of solute species at arbitrary concentration, as a function of the concentration of all species. Quantitative relationships between the species gradients and experimentally observable signal gradients are presented. The expressions are model-free and take into account both attractive and repulsive interactions between all species. In order to analyze data obtained from strongly nonideal solutions, a statistical thermodynamic model for repulsive solute-solute interactions is required. The relations obtained are utilized to analyze the dependence of the equilibrium gradient of ribonuclease A in phosphate-buffered saline, pH 7.4, upon total protein concentration. Experimental results are interpreted in the context of a model for weak self-association leading to the formation of significant amounts of oligomers at total protein concentrations exceeding 25 g/l.

Attention↗

PubMed2001

Weekly supplementation with iron and vitamin A during pregnancy increases hemoglobin concentration but decreases serum ferritin concentration in Indonesian pregnant women.

We investigated whether weekly iron supplementation was as effective as the national daily iron supplementation program in Indonesia in improving iron status at near term in pregnancy. In addition, we examined whether weekly vitamin A and iron supplementation was more efficacious than weekly supplementation with iron alone. One group of pregnant women (n = 122)was supplemented weekly with iron (120 mg Fe as FeSO4) and folic acid (500 microg); another group (n = 121) received the same amount of iron and folic acid plus vitamin A [4800 retinol equivalents (RE)]. A third ("daily") group (n = 123), participating in the national iron plus folic acid supplementation program, was also recruited. Data on subjects with complete biochemical data are reported (n = 190). At near term, hemoglobin concentrations increased, whereas serum ferritin concentrations decreased significantly in the weekly vitamin A and iron group, suggesting that vitamin A improved utilization of iron for hematopoiesis. Iron status in the weekly iron group was not different from that of the "daily" group. However, iron status decreased with daily supplementation if <50 iron tablets were ingested. Serum transferrin receptor concentrations increased in all groups (P < 0.01). Serum retinol concentrations were maintained in the weekly vitamin A and iron group, but decreased in the other two groups (P < 0.01). Thus, delivery of iron supplements on a weekly basis can be as effective as ona daily basis if compliance can be ensured. Addition of vitamin A to the supplement improved hemoglobin concentration.

Adult↗

PubMed2001

Measurement of blood urea concentration during haemodialysis is not an accurate method to determine equilibrated post-dialysis urea concentration.

BACKGROUND: The double-pool urea kinetic model requires the measurement of the blood urea concentrations 30 min after haemodialysis (C(t+30)) to calculate equilibrated Kt/V. However, it has been suggested that urea concentrations 30 min before the end of dialysis (C(t-30)) may be representative of C(t+30). The aim of this study was to validate this suggestion. METHODS: Twenty-two patients underwent haemodialysis for 180, 210, and 240 min. For each patient in each dialysis session, urea exponential decay curve was calculated. Because we measured C(t+30), we calculated the time (T(c)) before the end of dialysis that blood urea concentrations would be the same as C(t+30). In an additional 33 patients, we measured blood urea concentrations at T(c) and in C(t+30). RESULTS: We found that C(t-30) was significantly lower than C(t+30) independent of the duration of dialysis. However, there was a significant correlation between Kt/V(t-30) and Kt/V(t+30). The T(c) was 45 min before the end of dialysis. In the additional 33 patients, C(t-45) and C(t+30) were 54+/-17 and 52+/-17 mg/dl (NS), and Kt/V(t-45) and Kt/V(t+30) were 1.27+/-0.21 and 1.29+/-0.18 (NS), respectively. There were significant correlations between C(t-45) and C(t+30) (r=0.96; P<0.001), and between Kt/V(t-45) and Kt/V(t+30) (r=0.82; P<0.001). However, when measurements were analysed individually, 48% of the data points from C(t-45) vs C(t+30), and 42% of the data points from Kt/V(t-45) vs Kt/V(t+30) fell out of the 95% confidence interval of regression line. CONCLUSIONS: Although C(t-45) is useful to estimate Kt/V when assessing mean values, it is not suitable when assessing patients individually. This study demonstrates that the best method to calculate equilibrated Kt/V was a blood sample for urea concentrations 30 min after haemodialysis.

Adult↗

PubMed2002

Changes of cell volume and nitric oxide concentration in macula densa cells caused by changes in luminal NaCl concentration.

The luminal NaCl concentration ([NaCl]) at the macula densa (MD) controls both tubuloglomerular feedback (TGF) and renin release. Nitric oxide (NO) inhibits TGF sensitivity to a great extent. The NO concentration in the MD cells is not known. This study measured this concentration in MD cells with confocal microscopy in the isolated perfused thick ascending limb using a NO-sensitive fluorophore 4,5-diaminofluorescein (DAF-2). Calcein was used to measure cell volume changes. The loop perfusion fluid was a modified Ringer solution containing 10, 35, or 135 mM NaCl with a constant total osmolarity (290 mOsm), and the bath was perfused with the 135 mM NaCl solution. The results show that MD cell volume and NO concentration measured with DAF-2 DA increased considerably with increasing luminal [NaCl] and with calcium-free solutions in the lumen and bath. L-arginine (5 mM) increased NO concentration in the MD cells by 30%. 7-nitroindazole could totally inhibit the NO production caused by L-arginine and by increased luminal [NaCl]. In conclusion, the MD cell volume changes caused by the changes of luminal [NaCl] were quantitatively measured, and it was found that increasing the luminal [NaCl] resulted in an increase in cell volume. It was also found that NO formation in MD cells could be measured with DAF-2 and that NO production was increased through neuronal NO synthase activation with an increased luminal [NaCl]. An increased NO production will inhibit the vasoconstriction induced by the TGF and at the same time will reduce TGF sensitivity.

Animals↗

PubMed1991

Effect of restricted feeding on the relationship between hypophysial portal concentrations of growth hormone (GH)-releasing factor and somatostatin, and jugular concentrations of GH in ovariectomized ewes.

These studies characterized the secretion of GH-releasing factor (GRF) and somatostatin (SRIF) into the hypophysial portal circulation in ewes after long term restricted feeding. In addition, we examined the temporal relationship between the concentrations of these two hypothalamic peptides in portal blood and the concentration of GH in jugular blood. Six sheep were fed 1000 g hay/day (normal feeding) and 6 sheep were fed 400-600 g hay/day (restricted feeding). This resulted in a wt loss of 35% in restricted animals compared with 6% in control animals after 20 weeks. Fluctuations in portal levels of GRF indicated a pulsatile pattern of secretion with approximately 60% of pulses coincident with, or immediately preceding, a GH pulse. Similarly, 65% of GH pulses were associated with GRF pulses. Restricted feeding increased (P less than 0.01) mean ( +/- SEM) plasma GH levels (9.8 +/- 1.4 vs. 2.9 +/- 0.6 ng/ml) and mean GH pulse amplitude (7.9 +/- 1.8 vs. 2.8 +/- 0.3 ng/ml) but did not affect mean GH pulse frequency (6.0 +/- 1.1 vs. 5.7 +/- 1.1 pulses/8 h). The level of feeding had no effect on mean portal concentration of GRF (restricted: 5.5 +/- 0.8, normal: 6.6 +/- 1.4 pg/ml), GRF pulse amplitude (14.7 +/- 2.3 vs. 13.5 +/- 0.7 pg/ml), or GRF pulse frequency (5.3 +/- 1.1 vs. 6.7 +/- 0.9 pulses/8 h). Portal concentrations of SRIF in sheep on a restricted diet were half (P less than 0.01) those of sheep fed a normal diet (10.2 +/- 2.3 vs. 19.6 +/- 1.6 pg/ml). Pulses of SRIF were not significantly associated with changes in GH or GRF concentrations. These data indicate a functional role for hypothalamic GRF in initiating GH pulses. Furthermore, the increase in GH secretion in underfed sheep was most probably due to a decrease in the release of SRIF into hypophysial portal blood. Restricted feeding had no affect on GRF secretion, but because of the reduced exposure of the pituitary gland to SRIF, it is possible that responsiveness to GRF is enhanced.

Animals↗

PubMed2002

IFCC primary reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C. Part 1. The concept of reference procedures for the measurement of catalytic activity concentrations of enzymes.

This paper is the first in a series dealing with reference procedures for the measurement of catalytic activity concentrations of enzymes at 37 degrees C and with the certification of reference preparations. Other parts deal with: Part 2. Reference Procedure for the Measurement of Catalytic Concentration of Creatine Kinase; Part 3. Reference Procedure for the Measurement of Catalytic Concentration of Lactate Dehydrogenase; Part 4. Reference Procedure for the Measurement of Catalytic Concentration of Alanine Aminotransferase; Part 5. Reference Procedure for the Measurement of Catalytic Concentration of Aspartate Aminotransferase; Part 6. Reference Procedure for the Measurement of Catalytic fication of Four Reference Materials for the Determination of Enzymatic Activity of y-Glutamyltransferase, Lactate Dehydrogenase, Alanine Aminotransferase and Creatine Kinase at 37 degrees C. A document describing the determination of preliminary reference values is also in preparation.

Catalysis↗