Biomedical subjects
Publications and source records attributed to J Mårtensson.
Rat brain mitochondria were found to convert 3-mercaptopyruvate to 2-mercaptoacetate in the presence of NAD+, coenzyme A and thiamin pyrophosphate. The overall reaction probably consists of an oxidative decarboxylation of 3-mercaptopyruvate with 2-mercaptoacetyl CoA as a product which is then hydrolyzed to 2-mercaptoacetate by acyl CoA hydrolase.
Sulfur amino acid metabolism was studied in non-fasting nonketotic and ketotic juvenile-onset diabetic children and the results were compared to age-matched healthy children on an ordinary diet. An increased excretion of total sulfur and inorganic sulfate was found in diabetic children, probably a result of a decreased protein-serum synthesis and/or increased endogenous protein catabolism, although as a result of hyperglycemia a decreased tubular reabsorption may also have contributed. All diabetics showed a normal excretion of methionine. For cyst(e)ine and taurine an increased excretion was seen in ketotic diabetics, probably also a consequence of an increased endogenous protein degradation. As a sign of the latter, an increased output of 3-methylhistidine was also observed, a confirmation of earlier reports. The increased output of mercaptolactate and mercaptoacetate found in ketotic patients, was probably also a result of enhanced endogenous protein degradation. An increased urinary excretion of N-acetylcysteine was seen in diabetic children, which may reflect an enhanced availability to acetyl coenzyme A.
The endocrine response, and the relief of pain, following the extradural administration of morphine or a local anaesthetic agent bupivacaine (0.5%) were studied for 24h after abdominal surgery and compared with a control group given conventional i.v. morphine after operation. Samples were taken before and at 2, 4, 6, 12 and 24 h after skin incision. Pain relief in both extradural groups was significantly better when compared with the control group. In all three groups, the plasma concentration of cortisol was increased immediately after surgery. Thereafter, significantly lower values were seen in the extradural groups. Plasma adrenaline concentration was lower immediately after surgery only in the group given the extradural local anaesthetic. Plasma noradrenaline concentration remained unchanged after extradural local anaesthesia while an intermediate increase occurred after extradural morphine. Plasma noradrenaline concentration was significantly greater in the controls compared with both extradural groups. Our results indicate that extradural analgesia with a local anaesthetic drug can suppress the increases in the plasma concentrations of the catecholamines and cortisol after surgery. In contrast to extradural local anaesthetic extradural morphine cannot suppress the endocrine response immediately after surgery. However, later in the postoperative period, extradural morphine can suppress the endocrine response, thus indicating that postoperative pain is a factor involved in the stress response following surgery.
The urinary excretion of sulfur amino acids and their main degradation products was determined in patients subjected to various forms of gastrointestinal surgery or with bacterial overgrowth. A normal excretion of total sulfur and inorganic sulfate was found, indicating an adequate intake and maintained ability to absorb sulfur amino acids. An increased excretion of ester sulfate was observed in all groups except patients subjected to ileocecal resection or proctocolectomy, probably owing to bacterial overgrowth. A reduced excretion of methionine was observed in patients with gastric resection (Billroth I), ileocecal resection, and abnormal gut flora, whereas patients with jejunoileal bypass showed an increased excretion of methionine, probably a consequence of the impaired liver function. For cystathionine, a similar effect was found in patients with ileocecal resection and jejunoileal bypass. A reduced excretion of mercaptolactate was found in jejunoileal bypass patients. A low excretion of thiosulfate was seen in proctocolectomized patients, suggesting that the bacterial flora of the colon plays a role in the formation of thiosulfate. A low excretion of thiocyanate was found in gastric-resected patients, which may be due to a decreased ability to hydrolyze cyanogenic and/or thiocyanogenic glycosides or to a reduced intake of these compounds.
A method using high-performance liquid chromatography with mercury-based electrochemical detection has been developed for the determination of thiosulphate in urine. The chromatographic separation is based upon ion-pair formation between thiosulphate and tetrabutylammonium and reversed-phase chromatography. The method was compared with an earlier reported colorimetric assay and found to be superior with respect to specificity and sensitivity.
The excretion of sulfur-containing compounds was determined on the third and sixth day of life in male infants and the results were compared with those previously obtained on fed and fasting men. The output of total sulfur and inorganic sulfate was very low on the third day of life but had increased by the sixth day to levels found in the fasting men, whereas the excretion of mercaptolactate in the newborns decreased from the third to the sixth day of life. These results may be explained by the initial fasting state of neonates followed by an anabolic phase. Neonates excreted acid-labile ester sulfate and mercaptoacetate at levels similar to those found in adults, but the neonatal urine also contained sulfate esters (probably steroid sulfates) that required more drastic acid conditions for hydrolysis. Raised concentrations of sulfur-containing amino acids (methionine, cystathionine, cyst(e)ine and taurine) were found in neonatal urine in confirmation of earlier reports. The excretion of thiosulfate could only be determined in newborns on the sixth day and was low in comparison with that of adults. High urinary thiocyanate concentrations were found in newborns fed by tobacco-smoking mothers, whereas the excretion of thiocyanate was low in other newborns. The possible medical hazards from the exposure of neonates to thiocyanate are emphasized.
A patient with fulminant MH is presented. The metabolic changes in muscle tissue, whole blood and plasma are compared with those obtained from the porcine model. The samples were taken 1 h after treatment (including dantrolene sodium) had been commenced. Increased concentrations of lactate, pyruvate and citrate were found in muscle, whereas the concentrations of potassium, free inorganic phosphate and glycogen were reduced. The ATP, ADP and phosphoryl creatine concentrations remained unchanged. In blood, increased concentrations of alanine, lactate and glycerol were observed. An increase in carbon dioxide production was found. These changes are similar to those found in the porcine model.
Fourteen patients with classical rheumatoid arthritis and 7 healthy controls underwent a modified fast, containing diluted fruit and vegetable juices, for a 10-day period. To evaluate the effect of fasting on the inflammatory activity, plasma protein determinations were performed before and on the 10th day of fasting. Both patients and healthy controls developed reduced plasma levels of complement factor 3 (C3), orosomucoid and haptoglobin, although only the decrease in C3 and orosomucoid was greater in the patient group. An unchanged level in plasma of albumin, IgG, IgA, IgM and complement factor 4 was found. We conclude that determination of C3 and orosomucoid in plasma may be useful as indices of inflammation during fasting conditions.
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The urinary excretion of sulfur-containing compounds was studied before, on the third, and on the seventh day of fasting in 10 healthy subjects. The excretion of total sulfur, inorganic sulfate, ester sulfate, "non-sulfate sulfur", methionine, cystathionine, cysteine, N-acetylcysteine, taurine, thiosulfate and thiocyanate was decreased during fasting, whereas the excretion of mercaptoacetate was unaltered and that of mercaptolactate increased. The excretion of inorganic sulfate, taurine and thiocyanate was also decreased when calculated relative to that of total sulfur, suggesting that these compounds are derived mainly from dietary sulfur amino acids. The output of ester sulfate, methionine, cystathionine, cysteine and thiosulfate was unaltered in relation to that of total sulfur, indicating that these compounds are derived from both dietary and endogenous sulfur amino acids, liberated during protein catabolism. By contrast, the excretion of mercaptolactate and mercaptoacetate was increased relative to that of total sulfur, suggesting that these compounds are derived mainly from endogenous sulfur amino acids formed by the enhanced protein catabolism seen during fasting.
The urinary excretion of sulfur-containing compounds was studied in 11 burned patients during the first 10 days after injury. They were all given carbohydrate and fat by parenteral nutrition. Two patients also received large amounts of amino acids including methionine, whereas five patients were given amino acids including moderate amounts of methionine and cysteine. A sustained high excretion of mercaptolactate occurred in most patients. The excretion was not influenced by the type of parenteral nutrition, but related to the area of burned skin. A normal excretion of methionine, cyst(e)ine, inorganic sulfate, taurine, mercaptoacetate, thiosulfate, and thiocyanate was found at the end of the observation period in patients without amino acid therapy. Increased amounts of inorganic sulfate and methionine were excreted in patients receiving high doses of methionine, whereas an increased cyst(e)ine and taurine excretion was the most prominent finding in patients receiving moderate amounts of methionine and cysteine. These results indicate that burned patients have an unimpaired ability to metabolize sulfur amino acids. Patients not receiving amino acids or receiving moderate amounts of cysteine and methionine showed a negative sulfur balance, whereas patients given high doses of methionine maintained sulfur balance at near-zero levels. However, since signs of hepatic dysfunction appeared in the latter group, parenteral nutrition with amino acid mixtures containing high amounts of methionine is not recommended during the catabolic phase for burned patients.
Adults with untreated coeliac disease show signs of reduced central monoamine metabolism. The reason is obscure, and in the present study we investigated the brain availability of the monoamine precursors tryptophan and tyrosine in 11 untreated coeliac patients. The brain availability appeared to be unaffected in most of the patients, and the rise in serum tryptophan levels after oral casein administration was similar in coeliac and control subjects. Four of the 11 coeliac patients showed impaired brain availability with respect to tryptophan. Since they comprised all with a history of major psychiatric illness, this observation may have therapeutical implications for the management of depression in adult coeliac patients.
Therapy with balanced amino acid solution enriched in branched amino acids has been reported to favourably influence hepatic encephalopathy due to liver cirrhosis. We here report the same favourable effect in 3 patients aged 29, 30 and 41 yr with hepatic coma at least in part induced by acute viral hepatitis. The patients regained consciousness within 8, 12 and 12 h, respectively. The treatment was continued for 9, 6 and 5 days, respectively.
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The urinary excretion of inorganic sulfate, ester sulfate, taurine and total sulfur has been estimated in 18 patients with malignancy, and compared with those of an age-matched reference group. The absolute amount of inorganic sulfate was significantly lower in the cancer group, whereas an increased ester sulfate excretion was observed. Reduced excretion of total sulfate (inorganic plus ester sulfate) and increased excretion of "neutral sulfur" (total sulfur minus total sulfate) in the cancer group was calculated from these data. If these values were recalculated with respect to creatinine, no significant differences were found for inorganic and total sulfate between the two patient groups, whereas ester sulfate and the "neutral sulfur" fractions were still increased. The enlarged "neutral sulfur" could to a large extent be explained by an increased excretion of taurine. The mechanism behind these findings is discussed.
Adult Fanconi syndrome has been described as a manifestation of a latent form of myeloma. Since benign monoclonal gammopathy (BMG) is a latent form of myeloma we studied ten patients with this disease with respect to the adult Fanconi syndrome. These patients were selected from a larger group with BMG because of urinary excretion of monoclonal light chains. In no instance could a complete Fanconi syndrome be shown, but one patient, who also had a diabetic nephropathy, had very high levels of urinary beta 2-microglobulins. Two additional patients showed minor features included in the adult Fanconi syndrome. BMG does not seem to be associated with an increased risk of developing adult Fanconi syndrome.
We describe simple and precise methods for the determination of inorganic sulfate, ester sulfate, and total sulfur in urine. The methods are based on turbidimetry of sulfate as barium sulfate in the presence of a small amount of preformed barium sulfate and with polyethylene glycol as a stabilizing agent. Inorganic sulfate is directly determined, whereas ester sulfate is measured after removal of inorganic sulfate, followed by acid hydrolysis. Total sulfur is determined after wet oxidation of the sample with nitric acid and perchloric acid in the presence of vanadate as a catalyst. We also report excretion values for healthy persons on a self-selected diet. Men excrete significantly higher amounts of inorganic sulfate and total sulfur than women, but this sex-related difference becomes insignificant if excretion values are expressed relative to creatinine.