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Biomedical subjects

M Lie

Publications and source records attributed to M Lie.

At least 55 records · Page 3Linked to original sources
PubMed1977

Renal energy metabolism and sodium reabsorption after 2,4-dinitrophenol administration.

2,4-Dinitrophenol (DNP) (10 mg/kg body wt i.v.) increased renal cortical and outer medullary heat production rates and oxygen consumption by 70-90% in anesthetized dogs over a 90-min observation period without exerting any natriuretic effect. To examine whether DNP inhibited proximal reabsorption and increased distal delivery, ethacrynic acid (3 mg/kg body wt) was infused during maximal DNP effect. Sodium reabsorption fell by 14 +/- 6% in the cortex and 55 +/- 8% in the outer medulla, not significantly different from control experiments without DNP. Conversely, after ethacrynic acid administration, DNP had no additional natriuretic effect. Since DNP did not stimulate renal anaerobic metabolism (no lactate release), the effect of DNP was examined during hypoxia induced by intravenous infusion of NaCN (0.2 mumol/kg body wt-min) until renal metabolic rates fell. Subsequent infusion of DNP reduced tubular sodium reabsorption from 90 +/- 2 to 78 +/- 6%. Thus, DNP may raise renal metabolic rates by 70-90% without inhibiting sodium reabsorption, but, under conditions of hypoxia, DNP reduces sodium reabsorption and increases sodium excretion.

Anaerobiosis↗
PubMed1976

A simple amidolytic method for the determination of functional active antithrombin III.

A simple amidolytic method for the determination of the concentration of functionally active antithrombin III is described. Plasma is diluted with buffer containing EDTA and Polybrene. In stage I, diluted plasma is incubated with thrombin. EDTA retards fibrin polymerization, and plasma fibrinogen does not influence the assay. Polybrene makes the assay result independent of heparin. In stage II, remaining thrombin is determined with the chromogenic substrate benzoyl-Phe-Arg-p-NA. The method is simpler and has a higher accuracy than clotting methods. There is a close correlation between the results obtained with this assay and with immunoassay of antithrombin III.

Antithrombins↗
PubMed1976

Heparin cofactor activity and antithrombin III concentration in plasma related to age and sex.

Heparin cofactor activity and antithrombin III (At-III) concentration were measured in plasma from 219 healthy men and 177 women. Narrow ranges for heparin cofactor activity and At-III concentration were found. The standard deviation for heparin cofactor activity in men and women was 8.6 and 10.1, respectively, for At-III concentration 10.4 and 12.5. In men, mean heparin cofactor activity and mean At-III concentration decreased significantly with increasing age. In women, mean heparin cofactor activity and mean At-III concentration tended to be lower in fertile age. Hereditary At-III deficiency was detected in one individual.

Adolescent↗
PubMed1976

Dopamine-induced dissociation between renal metabolic rate and sodium reabsorption.

The stimulatory effect of dopamine on renal energy metabolism and its relationship to changes in tubular sodium reabsorption and plasma concentration of free fatty acids (FFA) were examined in anesthetized dogs. Dopamine infused intravenously at 25 mug/kg body wt-min for 30-60 min increased renal oxygen consumption (Rvo2) by 28 +/- 3%; glomerular filtration rate rose from 37 +/- 3 to 40 +/- 2 ml/min without significant changes in sodium excretion. Plasma FFA increased about 6 times. Total-body metabolic rate increased to 152 +/- 7% and fell to 119 +/- 5% of control after normalizing plasma FFA by beta-pyridylcarbinol; Rvo2 remained unchanged. Cortical and outer medullary heat accumulation rated increased to 137 +/- 6 and 133 +/- 10% after 1 h and to 163 +/- 18 and 179 +/- 26% of control after 2 h of dopamine infusion without further changes in sodium reabsorption. Furosemide reduced cortical and outer medullary metabolic rates as much as in control experiments (14 +/- 8 and 69 +/- 7%, respectively). Hence, dopamine exerts a renal calorigenic effect which cannot be accounted for by increased sodium reabsorption or attributed to increased supply of FFA.

Animals↗
PubMed1976

Antifactor Xa activity measured with amidolytic methods.

Methods for the assay of antifactor Xa activity in the presence and absence of heparin are described. Diluted plasma is incubated with bovine, activated factor X (Xa) in stage I, and remaining Xa is measured with the chromogene substrate Bz-Ile-Glu-Gly-Arg-pNA in stage II. In the presence of heparin, the inactivation is completed in 30 sec, and this method measures total Xa-inactivating capacity in diluted plasma (Method I). In a clincal material, this capacity showed a strong positive correlation (r=0.85) to the thrombin-inactivating capacity of diluted heparinized plasma (heparin cofactor activity) and apparently reflects antithrombin III (At-III) concentration. In the absence of heparin, the inactivation of factor xa occurs slowly. With an incubation of 5 min, about 25% of Xa is inactivated, and this assay reflects initial inactivation of Xa (Method II). With this method, a positive, but less strong correlation to the thrombin-inactivating capacity was found (r=0.58), indicating that inhibitors different from At-III accounts for a minor part of the initial inactivation. Determinations in plasma, in which At-III was removed by immunoadsorption, indicated that At-III accounts for about 80% of the initial inactivation. The results of the assays are not significantly influenced by varying concentrations of fibrinogen, fibrinogen degradation products or heparin in the test plasma.

Amides↗
PubMed1975

Effect of cyanide on renal metabolic rate and glomerulotubular balance.

Measurements of anesthetized dogs by the heat-accumulation technique showed that cyanide reduced equally the metabolic rates of outer medulla and cortex, whereas combined infusion of ethacrynic acid and chlorothiazide reduced mainly the metabolic rate of the outer medulla. During ethacrynic acid and chlorothiazide infusion, cyanide reduced the remaining sodium reabsorption by an average of 19% and the remaining cortical metabolic rate by 43%, but had no additional effect on the outer medullary metabolism. Metabolic rates remained essentially constant when glomerular filtration rate (GFR) was raised during cyanide infusion from 63 plus or minus 3 to 135 plus or minus 7% of control by carotid constriction or intravenous infusion of angiotensin. Glomerulotubular balance, defined as proportional relationship between sodium reabsorption and GFR during infusion of ethacrynic acid and chlorothiazide, was present only at GFR less than 80% of control in experiments with and without cyanide infusion. We conclude that cyanide inhibits proximal energy-requiring sodium transport which cannot be inhibited by ethacrynic acid and chlorothiazide, but does not alter the range of GFR over which glomerulotubular balance applies.

Angiotensin II↗