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Cardiac troponin I (troponin lc) has been measured on the Dade Stratus analyzer. Cardiac specificity has been studied in patients presenting a rhabdomyolysis syndrome. The obtained results clearly demonstrated that this parameter may be used as a specific marker of myocardial injury, in contrast to total creatine kinase- or mass CK-MB measurements. In unstable angina, two groups of patients may be defined: one group with elevated troponin lc (> 0.60 microgram/L; 31 patients, group I), one other with normal troponin lc (< 0.35 microgram/L; 49 patients; group II). Quantitative angiographic analysis was performed on 50 patients including 18 patients from group I. Group I showed a more severe culprit lesion than group II. All the results suggested that troponin Ic might be an indicator of severity in unstable angina.

Phosphoglycerate kinase (MgATP 3-phospho-D-glycerate 1-phosphotransferase, EC 2.7.2.3) has been isolated from rat liver with a purification ratio of 960 and a specific activity of 300 IU/mg of protein. The purity of the enzyme preparations was estimated by polyacrylamide gel electrophoresis. The molecular weight, determined by gel filtration is 42 000. The "subunit" size of phosphoglycerate kinase as determined by sodium dodecyl sulfate gel electrophoresis is 46 000, indicating that the enzyme is monomeric. The rate of the enzyme reaction as a function of the concentration of D-3-phosphoglycerate indicated the usual Michaelis Menten relationship. The rate of the enzyme reaction as a function of the concentration of MgATP2- did not fit the usual Michaelis Menten relationship: two distinct regions can be fitted with different straight lines and suggest the presence of two sites for the Mg ATP2-. This hypothesis seems to be confirmed by the study of the action of the free and complexed nucleotides.

70 patients with colic diverticular disease and 50 control subjects were compared. Sexes and ages were matched in the two groups. Significant higher frequencies of alcoholism (P < 0,00001), hyperlipidemia (P < 0,0001), impaired oral glucose tolerance test (P < 0,001), hyperuricemia (P < 0,01) and atherosclerosis (P < 0,000001) were noted in the diverticular group. Hypothesis about pathogenesis of diverticular disease are suggested.

Incubation of hepatocytes from 24 h-starved rats in the presence of 0.5 mM-adenosine decreased gluconeogenesis from lactate, but not from alanine. The inhibition of gluconeogenesis was associated with a stimulation of ketone-body production and an inhibition of pyruvate oxidation. These metabolic changes were suppressed in the presence of iodotubercidin (an inhibitor of adenosine kinase), but were reinforced in the presence of deoxycoformycin (an inhibitor of adenosine deaminase); 2-chloroadenosine induced no change in gluconeogenesis from lactate. These data indicate that the inhibition of gluconeogenesis by adenosine probably results from its conversion into adenine nucleotides. In the presence of lactate or pyruvate, but not with alanine or asparagine, this conversion resulted in a decrease in the [ATP]/[ADP] ratio in both mitochondrial and cytosolic compartments. Adenosine decreased the Pi concentration with all gluconeogenic substrates.

Serum creatine kinase activity was measured during the first post-natal days in healthy full-term and premature infants. The CK isoenzymes (CK-MM, MB and BB) were separated using ion-exchange column chromatography. Total CK activity is lower for premature infants than for full-term infants at the same time-periods. However the separation of the CK isoenzymes shows that the same normal values for the CK-BB (expressed as U/l) may be used for the two groups of infants.

The effect of adenosine was tested on the energetic metabolism of fed rat liver cells after isolation. The cells were incubated in a buffered saline medium with glucose (5 mM) and adenosine (1 mM) for 30 minutes at 37 degrees C. This increased the concentration of the adenylic nucleotides ATP (+57 per cent, ADP (+39 per cent). Cyclic AMP was increased (+50 per cent) and the intracellular inorganic phosphate decreased (-22 per cent). These changes were accompaned by a decrease of glycogenolysis, glucose consumption and lactate production. Measurement of glycolytic intermediates showed decreased concentrations of fructose 1,6-bis-phosphate and 3-phosphoglycerate proportional to the increase in ATP concentration. The near-equilibrium of the glyceraldehyde 3-phosphate dehydrogenase-phosphoglycerate kinase system was not modified by adenosine. The decrease of the NAD+/NADH ratio along with the increase of the ATP/ADP X PO4 ratio explains the decrease of 3-phosphoglycerate. The decrease in glucose consumption can be explained by the cross over at the phosphofructokinase stage with the decrease of fructose 1,6-bisphosphate. The major part of adenosine was deaminated as indicated by an increase in the production of ammonia and urea. The effects of inosine, or adenosine along with an inhibitor of adenosine deaminase (pentostatin) suggest that adenosine acts on the glucose consumption through adenylic nucleotides. However the increase of the adenylic nucleotide level cannot totally explain the other metabolic changes: decrease of the NAD+/NADH cytoplasmic ratio, constancy of this ratio in mitochondria, decrease of gluconeogenesis from lactate. A direct action of adenosine can therefore be expected.

The kinetic properties of rat liver phosphoglycerate kinase were investigated in the forward direction of the reaction (utilization of ADP). The kinetic studies were performed in an assay system using combined hexokinase/glucose-6-phosphate dehydrogenase as an ATP trap. The Km values for Mg ADP1- and 1,3-diphospho-D-glycerate were approximately 0.11 and 0.006 mM, respectively. Reciprocal plots of 1/v versus 1/ (Mg ADP1-) at different fixed concentrations of 1,3-diphospho-D-glycerate and 1/v versus 1/ (1,3-diphospho-D-glycerate) at different fixed concentrations of Mg ADP1- were apparently parallel. However, product inhibition studies (3-phospho-D-glycerate), dead-end inhibition studies (2,3-diphospho-D-glycerate), and adenosine and AMP inhibition patterns yielded results consistent with a rapid equilibrium random mechanism in which the binding of one substrate greatly decreases the affinity of the enzyme for the second substrate. Existence of two sites for 3-phospho-D-glycerate is suggested.

The addition of ethyl alcohol to the elution buffer permits one to separate hemoglobin A1c from other glycosylated hemoglobins on a Biorex 70 microcolumn.

Effects of adenosine on purified rat liver phosphofructokinase and phosphoglycerate kinase activity were investigated in vitro. Stimulation by adenosine of the phosphofructokinase has been observed at low concentrations, but the activity was markedly inhibited at high concentrations. Adenosine was an inhibitor of the phosphoglycerate kinase : Lineweaver-Burk analysis indicated that adenosine inhibition was competitive with ATP and non competitive with 3-phosphoglycerate. An interpretation of these results is proposed.