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W H Baricos

Publications and source records attributed to W H Baricos.

At least 37 records · Page 2Linked to original sources
PubMed1984

Increased cathepsin D-like activity in cortex, tubules, and glomeruli isolated from rats with experimental nephrotic syndrome.

We have examined the activity and distribution of cathepsin D (EC 3.4.23.5), a major renal lysosomal endoproteinase, in the various anatomical and functional areas of normal rat kidney. Cathepsin D-like activities (delta A280/h per mg of protein) in normal rat tissues were: cortex, 0.78 +/- 0.05, n = 37; medulla, 0.62 +/- 0.03, n = 12; papilla, 0.63 +/- 0.04, n = 12; tubules, 0.74 +/- 0.04, n = 28; glomeruli, 0.59 +/- 0.03, n = 28; and liver, 0.41 +/- 0.02, n = 28. Enzyme activity was maximal at pH 3.0-3.5 and inhibited more than 90% by pepstatin (6.7 micrograms/ml), suggesting that the enzyme is cathepsin D. In subsequent experiments we measured cathepsin D-like activity in cortex, tubules and glomeruli isolated from rats with puromycin aminonucleoside (PAN)-induced nephrotic syndrome. Treated animals (15 mg of PAN/100g body wt., intraperitoneally) developed proteinuria beginning 4 days after injection and exceeding 900 mg/24h on day 9. In two separate experiments involving 52 animals we observed a significant increase in cathepsin D-like activity in cortex (+82.7%), tubules (+109.6%) and glomeruli (+54.7%) isolated from PAN-treated rats killed during marked proteinuria (day 9, mean total urinary protein excretion: 937 +/- 94 mg/24h). This increase was observed whether the activity was expressed per mg of DNA or per mg of protein. Increased cathepsin D-like activity was first observed in cortex and tubules coincident with the onset of proteinurea (day 4, mean total urinary protein excretion: 112 +/- 23 mg/24h). In contrast with the significant elevation of renal cathepsin D-like activity, the activity (nmol/h per mg of protein) of alpha-L-fucosidase (EC 3.2.1.51), a non-proteolytic enzyme, was markedly decreased in the identical samples used for the measurement of cathepsin D-like activity: cortex (-46.4%); tubules (-46.1%); and glomeruli (-38.5%). In addition to changes in renal enzyme activities, PAN-treated rats excreted large amounts of cathepsin D-like activity in their urine (beginning on day 3) compared with nearly undetectable cathepsin D-like activity in the urine from control rats. The significant increases in glomerular and tubular cathepsin D activity may reflect an important role for this enzyme in the pathophysiology associated with PAN-induced nephrotic syndrome.

Animals↗
PubMed1984

Cerebral phospholipid content and Na+,K+-ATPase activity during ischemia and postischemic reperfusion in the mongolian gerbil.

Using bilateral carotid artery occlusion in adult gerbils we examined the effects of ischemia and ischemia/reperfusion on cerebral phospholipid content and Na+,K+-ATPase (EC 3.6.1.3) activity. In contrast to the large changes in phospholipid content and membrane-bound enzyme activity that have been observed in liver and heart tissues, we observed relatively small changes in the cerebral content of total phospholipid, phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE) following ischemic intervals of up to 240 min. Following 15 min of ischemia the cerebral content of sphingomyelin (SM) was decreased to less than 50% of control values but returned to near-normal levels with longer ischemic periods. Significant decreases in the cerebral content of phosphatidylinositol (PI) and phosphatidic acid (PA) were observed following shorter intervals of ischemia (15-45 min). Na+,K+-ATPase activity of cerebral homogenates prepared from the brains of gerbils subjected to 30-240 min of ischemia was decreased but significantly different from control activity only after 30 min of ischemia (-29%, p less than or equal to 0.05). With the exception of PS, reperfusion for 60 min following 60 min of ischemia resulted in marked increases in cerebral phospholipid content with PC, SM, PI, and PA levels exceeding and PE levels equal to preischemic values. Longer periods of reperfusion (180 min) resulted in decreases in cerebral phospholipid content toward (PC, SM, PI, and PA) or below (PE) preischemic levels. In contrast, the cerebral content of PS significantly decreased during reperfusion (-51% at 60 min, p less than or equal to 0.05) and remained below preischemic values even after 180 min of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Activation of purified guanylate cyclase by nitric oxide requires heme. Comparison of heme-deficient, heme-reconstituted and heme-containing forms of soluble enzyme from bovine lung.

Bovine lung soluble guanylate cyclase was purified to apparent homogeneity in a form that was deficient in heme. Heme-deficient guanylate cyclase was rapidly and easily reconstituted with heme by reacting enzyme with hematin in the presence of excess dithiothreitol, followed by removal of unbound heme by gel filtration. Bound heme was verified spectrally and NO shifted the absorbance maximum in a manner characteristic of other hemoproteins. Heme-deficient and heme-reconstituted guanylate cyclase were compared with enzyme that had completely retained heme during purification. NO and S-nitroso-N-acetylpenicillamine only marginally activated heme-deficient guanylate cyclase but markedly activated both heme-reconstituted and heme-containing forms of the enzyme. Restoration of marked activation of heme-deficient guanylate cyclase was accomplished by including 1 microM hematin in enzyme reaction mixtures containing dithiothreitol. Preformed NO-heme activated all forms of guanylate cyclase in the absence of additional heme. Guanylate cyclase activation was observed in the presence of either MgGTP or MnGTP, although the magnitude of enzyme activation was consistently greater with MgGTP. The apparent Km for GTP in the presence of excess Mn2+ or Mg2+ was 10 microM and 85-120 microM, respectively, for unactivated guanylate cyclase. The apparent Km for GTP in the presence of Mn2+ was not altered but the Km in the presence of Mg2+ was lowered to 58 microM with activated enzyme. Maximal velocities were increased by enzyme activators in the presence of either Mg2+ or Mn2+. The data reported in this study indicate that purified guanylate cyclase binds heme and the latter is required for enzyme activation by NO and nitroso compounds.

Animals↗
PubMed1982

Mitochondrial chemiluminescence elicited by acetaldehyde.

Acetaldehyde-dependent chemiluminescence has been found to be a sensitive technique for the study of superoxide and hydrogen peroxide formation in beef heart mitochondria. The system responds to ATP and antimycin A with increased emission intensities and to ADP and rotenone with decreased intensities, indicating that the chemiluminescence reflects the energy status of the mitochondrion. These effects are based on the ability of acetaldehyde to react with superoxide and hydrogen peroxide to form metastable intermediates which decay spontaneously with the emission of light. Additionally, these intermediates can react with cyanide to give alternative products which can also decay with the emission of light, the cyanide-evokable chemiluminescence. The interaction of acetaldehyde with mitochondria is complex because acetaldehyde can serve as a hydrogen source for NADH and as an inhibitor (at high concentration) of electron transport, and appears to be a reducing agent for a heat-stable site that autoxidatively generates HOOH from O2-.. Inasmuch as acetaldehyde is a metabolite of ethanol, this broad spectrum of reactivity may play a role in the hepatic and cardiac toxicity that is associated with alcoholism. The heat-stable site that generates HOOH from O2-. has been studied further and appears to contain vicinal dithiol which is primarily responsible for the cyanide-evokable chemiluminescence.

Acetaldehyde↗
PubMed1982

Enzymatic and immunologic quantitation of erythrocyte superoxide dismutase in adults and in neonates of different gestational ages.

Human erythrocyte superoxide dismutase (SOD) was purified and specific antiserum was raised in rabbits. Enzyme preparations from adults and from newborns were shown to be indistinguishable in their immunologic and electrophoretic properties. Erythrocyte SOD was quantitated in blood specimens from adults and in cord blood specimens from neonates of different gestational ages, using both an immunologic and an activity assay. The mean values of SOD concentration and SOD activity for adults and for newborns of average size for gestational age (AGA) showed no significant difference. Adult red cells contained 28.0 +/- 8.3 SOD units/mg hemoglobin (Hgb) whereas AGA neonatal red cells had 28.5 +/- 8.3 SOD units/mg Hgb. Immunologic quantitation by single radial immunodiffusion revealed 0.69 +/- 0.07 micrograms SOD/mg Hgb in adults and 0.70 +/- 0.14 micrograms SOD/mg Hgb in the AGA neonates; however, the SOD concentrations from both small for gestational age (SGA) and large for gestational age (LGA) neonates were significantly lower than those of the AGA neonates and the adults (SGA: 0.57 +/- 0.24 micrograms SOD/mg Hgb, P less than 0.05; LGA: 0.59 +/- 0.16 micrograms SOD/mg Hgb, P less than 0.05).

Adult↗
PubMed1982

KCN-induced urinary chemiluminescence (UCL): inhibition by ascorbic acid.

Addition of KCN or H2O2 to normal human urine resulted in chemiluminescence (CL). The CL increased with increasing concentrations of KCN and H2O2 and with increasing pH of the reaction mixture. KCN-induced UCL was markedly inhibited by exogenously added ascorbic acid (AA) and to varying degrees by glucose, albumin, tryptophan, hemoglobin and histidine. In contrast H2O2-induced UCL was significantly inhibited only by tryptophan. Mannitol and ethanol (hydroxyl radical scavengers) had little effect on either KCN-or H2O2-induced UCL. The KCN-sensitive and the H2O2-sensitive components were eluted in different positions from a Sephadex G15 column indicating chemically distinct compounds with molecular weights of less than 1500 daltons. We conclude that the UCL produced by H2O2 and KCN arise via interactions with chemically distinct compounds present in the urine.

Ascorbic Acid↗