Biomedical subjects
Publications and source records attributed to L Cynober.
The measurement of plasma amino acid concentrations (50 samples) by gas-chromatography and by ion-exchange chromatography (IEC) indicates that the two methods correlate well. However, IEC provides higher values for proline, threonine and serine. The results are confirmed by the study of normal values obtained in healthy subjects.
Serum creatine-kinase (CK) activity was monitored during ESWL in order to investigate muscular or even myocardial injury. Despite a significant increase at the sixth hour, the values observed remained in the normal range. The authors were therefore unable to conclude on any significant muscular damage.
The Koné "Progress," a discrete analyzer for use in clinical chemistry, was evaluated. The apparatus exhibited a high degree of precision and linearity, and no carryover. Results correlated well with those obtained with our routine equipment [Olli C + D (Koné), G-300 (Greiner), and Corona (Clinicon)].
We report a case of rhabdomyolysis with acute renal failure during recovery from thermal burn injury. The late occurrence of this unusual complication is emphasized and possible etiological factors are discussed.
Plasma vasoactive intestinal polypeptide (VIP) concentrations were measured at different days after burn injury. A significant decrease in VIP levels was observed on days 7 and 10. The influence of enteral nutrition was also investigated: a rise in plasma polypeptide levels was found at 60 min after nutrition restart on days 4 and 7 after injury. In burn patients, VIP may be involved in the multiple metabolic and hormonal responses which lead to an increase in the hypercatabolic state. The decrease in these polypeptide values should reflect enhanced utilisation or complex hormonal regulation. After enteral nutrition, the stimulation of VIP secretion disappeared after day 7 after burn injury. This phenomenon is probably mediated by a process of adaptation to continuous enteral nutrition.
The study concerns two groups of seven burn patients matched for age, weight and total burn surface. Both groups received conventional enteral nutrition, while one was given a 10 g/day alpha-ketoglutarate ornithine (OKG) supplement. Femoral venous and arterial blood was taken from day 2 to day 13 post-burn in order to determine levels of amino acids, nonesterified fatty acids (NEFA), glucose and lactate. In the control group large negative arterio-venous differences (DeltaA-V) were observed in amino acid and lactate levels whereas they were significantly lower with regard to Hyp, Gly, Lys and Ala in the OKG-treated group. DeltaA-V was near zero for glucose and NEFA in both groups. These results support the view that OKG-therapy limits the output of amino acids in the leg and that glucose and NEFA do not constitute the main fuel in muscle.
Plasma branched-chain keto acids (BCKA) and glucose-alanine cycle-related substances were measured in venous and arterial blood following burn injury. It was found that the three BCKA diminished with a minimum on day 7 while pyruvate increased. Alanine and glutamate + glutamine also decreased but plasma branched-chain amino acids (BCAA) did not vary. BCKA and gluconeogenic amino acids were liberated by peripheral tissues whereas BCAA were not. By analogy with the fate of alanine, a reduction in plasma BCKA associated with a high release by peripheral tissues might involve an increase in their hepatic metabolism. The BCKA would then give rise to ketone bodies used by the peripheral tissue. This step would complete the glucose-alanine cycle described by Cahill in hypercatabolic states where energy requirements are intense and similar to those found in burn injuries.
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The action of insulin on glucose uptake in human or animal cultured fibroblasts has been subject of several studies. The results obtained vary greatly from one study to the next with regard to the response to the hormone but this should be related to the various and somewhat questionable experimental protocols. In general, it would appear that fibroblasts are less sensitive to insulin than adipocytes in the stimulation of sugar transport. This might be due to a smaller number of insulin receptors in fibroblasts or to a poor affinity for the hormone. In addition, as the response to insulin depends greatly on culture conditions (confluency, serum or glucose starvation ...) this cellular model must be used carefully in studies concerning insulin action on glucose uptake.
Myoglobin is released into the blood after burn injury. We measured it and other analytes in blood collected from 22 burn patients two to seven times during their recovery. There was a significant correlation between myoglobinemia and creatine kinase (CK) activity in serum (r = 0.764; p less than 0.001). In a group of 14 thermal-burn subjects a correlation was found between burn depth (clinically expressed as Unit Burn Surface) and both myoglobinemia (r = 0.825; p less than 0.01) and CK activity (r = 0.686; p less than 0.01). In eight thermal-burn patients who were recovering satisfactorily, myoglobin and CK activity measured on days 2, 4, 7, 10, and 13 after injury were significantly increased (p less than 0.05) on days 2, 4, and 7. Evidently myoglobinemia and CK activity are good biological markers of burn depth, and reflect muscle damage equally well.
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Plasma phenylalanine concentrations were measured on the seventh postburn day in patients with burn surface areas ranging from 1 to 39%. Hepatic function (glutamate-pyruvate transaminase, prothrombin time) and protein breakdown (nitrogen balance, urine 3-methylhistidine/creatinine ratio) were evaluated in parallel. Plasma phenylalanine concentrations in patients with normal hepatic function and those with hepatic failure were similar. A correlation was shown between phenylalaninemia and nitrogen balance for all patients but phenylalaninemia only correlated with the urine 3-methyl-histidine/creatinine ratio in patients with burn surface areas under 20%. Taken as a whole, the data suggest that the determination of plasma phenylalanine concentration is a valuable test to assess the nitrogen balance in burn patients. This test, when performed on day 7, is particularly relevant in patients with normal hepatic function and either slight or moderate burn injury.
We evaluated the distribution of values for prostatic acid phosphatase (EC 3.1.3.2) activity and zinc concentration in semen of 80 men without clinical evidence of prostatic disease. Both substances have log normal distributions. Reference intervals were defined by parametric tests after logarithmic transformation of data and by nonparametric tests. There is a correlation between zinc concentration and prostatic acid phosphatase activity in semen.
2-deoxyglucose uptake rates at low sugar concentrations (less than 500 microM) appeared to be lower than those predicted by the Michaelis-Menten model which correctly described higher concentrations. This phenomenon which we will call concentration-dependent transport lag, was also observed for L-glucose uptake which suggest that this phenomenon is carrier-independent. A model involving the perimembrane space is developed which, for L-glucose, gives k1 = 0.931 +/- 0.072 X 10(-6) l X mg protein-1 X minute-1, k2 = 2.97 +/- 0.19 X 10(-7) l X mg protein-1 X minute-1 and So = 88,8 +/- 4,3 microM; where k1 is the diffusion constant in the cell membrane, k2 is the diffusion constant in the perimembrane space and So the sugar concentration required in the external medium in order to provide an équivalent sugar concentration in the transport carrier area.
A comparison of plasma amino acid levels was made between two groups of burn subjects, septic and non-septic. On day 4 after injury, results do not show any differences between patients who later went on to develop sepsis on day 7 and those who remained non-septic. Similarly, no differences between these two groups were discernable on day 7. Thus metabolic variations induced by septicemia do not seem to modify the usual burn-induced amino acid variations; consequently, plasma amino acid determination in burn patients do not appear to predict septicemia.
In accordance with previous results obtained with traumatized patients, ornithine alpha-ketoglutarate (OKG) was orally administered to 10 healthy subjects fed with a standardized regimen. Six similarly fed control subjects received only water. Plasma and 24-h urinary amino acids and alpha-ketoglutarate, plasma glucose, plasma insulin, and urine urea were all measured. After administration of ornithine alpha-ketoglutarate, the rapid decrease in blood ornithine to basal values, the absence of any increase in plasma alpha-ketoglutarate levels, and the minimal increase in ornithine, alpha-ketoglutarate, and urea urinary elimination, all indicated intense metabolism and utilization of the two compounds. These results suggest that the hyperornithinemia observed in 4-h fasting, traumatized patients receiving ornithine alpha-ketoglutarate reflects a metabolic perturbation in the utilization of this amino acid after trauma, rather than a hypothetical slow utilization. On the other hand, ornithine alpha-ketoglutarate induced an increase in insulin levels causing hypoglycemia and probably a decrease in plasma levels of several amino acids.
Eight severely burned patients received 10 grams twice a day of enterally administered ornithine alpha-ketoglutarate. Variations in their plasma and urinary amino acid levels were compared with those from six severely burned control patients. The study covered the period from the fourth day to the twenty-eighth day after injury. Essential differences between the two groups were that plasma ornithine and proline increased until day 13 in the treated group, plasma phenylalanine levels were higher in the control group except on day 13, the peak, on the twenty-first day, in plasma concentrations of valine, leucine, isoleucine, tyrosine, lysine, proline, and ornithine, in the control group was not found in treated subjects, and urinary amino acids were lower on day 28 in the treated group. These results suggest that ornithine alpha-ketoglutarate administration lowered protein catabolism after injury, probably through a process mediated by increased secretion of insulin and human growth hormone.