Molecular and cellular biochemistry
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Mol. Cell. Biochem. · Oct 1992
Comparative StudyRelease of heart fatty acid-binding protein into plasma after acute myocardial infarction in man.
The release of cytoplasmic heart fatty acid-binding protein (H-FABP) into the plasma of cardiac patients up to 38 hr after the onset of the first clinical symptoms of acute myocardial infarction (AMI) was studied, using a sensitive direct and noncompetitive Enzyme Linked Immunosorbent Assay of the antigen capture type (sandwich ELISA), newly developed for the measurement of small amounts of human H-FABP in plasma samples. Plasma levels of H-FABP were compared with plasma activity levels of the myocardial cytoplasmic enzymes creatine kinase MB (CK-MB) and alpha-hydroxybutyrate dehydrogenase (alpha-HBDH). Upper normal levels of H-FABP (19 micrograms/l), CK-MB (10 U/l) and alpha-HBDH (160 U/l) as determined in plasma from 72 blood donors served as threshold levels. ⋯ Serial time curves of the plasma contents of H-FABP reveal that after myocardial infarction H-FABP is released in substantial amounts from human hearts. In 18 out of 22 patients with established AMI the plasma FABP level was at or above the threshold level in blood-samples taken within 3.5 hr after the first onset of symptoms of AMI, while for CK-MB this applied to 9 patients and for alpha-HBDH to 6 patients. These findings suggest that for an early indication of acute myocardial infarction in man cytoplasmic heart fatty acid-binding protein is more suitable than heart type creatine kinase MB and/or alpha-hydroxybutyrate dehydrogenase.
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Mol. Cell. Biochem. · Oct 1992
L-propionylcarnitine and myocardial performance in stunned porcine myocardium.
Recently, we showed that L-propionylcarnitine did not affect recovery of regional contractile function of porcine myocardium subjected to 1 h of low-flow ischemia followed by 2 hr of reperfusion. In that study, ischemia may have been too severe and/or the duration of reperfusion too short to detect a beneficial effect of the compound. Therefore, in the present study we investigated the effects of saline (control group; n = 14) or pretreatment with L-propionyl-carnitine (3 days of 50 mg/kg p.o. b.i.d. + 50 mg/kg i.v. prior to the experiment; n = 13) on recovery of regional contractile function of the myocardium in open-chest anesthetized pigs, subjected to two cycles of 10 min of left anterior descending coronary artery (LADCA) occlusion, each followed by 30 min of reperfusion. ⋯ During the second occlusion-reperfusion cycle similar values for SSLS were observed. In the treated animals, SSLS of the LADCA-perfused area was slightly improved after the second occlusion-reperfusion cycle (p = 0.056). This effect did not result in an overall improvement in cardiac pump function.(ABSTRACT TRUNCATED AT 250 WORDS)
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Mol. Cell. Biochem. · Mar 1988
Subtypes of dorsal root ganglion neurons based on different inward currents as measured by whole-cell voltage clamp.
Electrophysiological and pharmacological properties distinguished subtypes of adult mammalian dorsal root ganglion neurons (DRGn) in monolayer dissociated cell culture. By analogy of action potential waveform and duration, neurons with short duration (SDn) and long duration (LDn) action potentials resembled functionally distinct subtypes of DRGn in intact ganglia. Patch clamp and conventional intracellular recording techniques were combined here to elucidate differences in the ionic basis of excitability of subtypes of DRGn in vitro. ⋯ Large neurons, presumable SDn, had predominantly TTX-sensitive current and little TTX-resistant current. The predominant inward current of small neurons, presumably LDn, was TTX-resistant with a smaller TTX-sensitive component. By analogy to findings from intact ganglia, these results suggest that fundamentally different ionic currents controlling excitability of subtypes of DRGn in vitro may contribute to functional differences between subtypes of neurons in situ.
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Mol. Cell. Biochem. · Apr 1979
Polymorphism in fowl serum albumin. VI. Changes in in vitro protein synthesizing activity in developing embryonic fowl liver.
Cell-free protein synthesizing systems were prepared from the livers of chick embryos at selected ages and the characteristics of individual fractions were compared. While polysomes showed decreasing size with older embryos, isolated polysomes did not differ significantly in amino acid incorporating activity when assayed with standard cell sap. When assayed with standard polysomes, cell sap activity decreased with increasing developmental age whether incorporation was measured using (3H)lysine, (3H)leucine, or [3H]aminoacyl-tRNA. ⋯ A larger increase in ribonuclease activity was observed during development; however, nuclease inhibitor activity was absent before day 15 but increased thereafter. Aminoacyl-tRNA sythetase activity did not vary significantly. It is proposed that the observed changes in the rate of cell-free protein synthesis result not only from increasing ribonuclease activity with increasing developmental age but also from changes in the activity of other soluble factors.
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Mol. Cell. Biochem. · Dec 1975
L-tyrosine: 2-oxoglutarate aminotransferase induction by hydrocortisone in the thymus of the white rat.
Hydrocortisone hemisuccinate within 4 hours after in vivo administration produced an increase in precursor incoporation into rat thymus RNA and proteins in the whole animal. From these results, together with information obtained from measurements of the tyrosine aminotransferase activity and the action of mitomycin C administered one hour before the injection of hydrocortisone, it can be concluded that the increase in tissue level of the enzyme, consequent to hydrocortisone treatment, results from an increased rate of biosynthesis of the enzyme, which participates in the catabolic processes of proteins in glucocorticoid sensitive thymus cells.