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Biomedical subjects

K Hiwada

Publications and source records attributed to K Hiwada.

At least 361 records · Page 20Linked to original sources
PubMed1983

Characterization and immunohistologic demonstration of angiotensin-converting enzyme in human renal cell carcinoma.

Angiotensin-converting enzyme (ACE, EC 3.4.15.1) was demonstrated in the tissue of human renal cell carcinoma and its cultured cells by immunofluorescence and immunohistochemistry using a specific rabbit antibody to human kidney ACE. The biochemical properties of the partially purified enzyme from the tumor tissue were identical with the pure enzyme from normal kidney with respect to Km, optimal pH, chloride ion activation and heat sensitivity. Catalytic activities of tumor and normal kidney enzymes were similarly inhibited by an ACE inhibitor, captopril, and by the antibody to human kidney ACE. However, double immunodiffusion analysis showed spur-forming immunoprecipitin bands between the tumor and normal kidney enzyme. These data suggest that human renal cell carcinomas have a new isozyme of ACE differing in part immunologically from the enzyme of normal kidney.

Adenocarcinoma↗
PubMed1982

Biochemical and immunological studies of angiotensin converting enzymes from human, bovine, dog, hog, rabbit, rat and sheep kidneys.

1. Molecular and kinetic properties of angiotensin converting enzymes from seven different species' kidneys were similar concerning apparent molecular weight, heat sensitivity, Km value, optimum pH, activation by chloride ion, and inhibition by specific converting enzyme inhibitors (captopril and SA 446). 2. Rabbit antibody against pure human kidney enzyme cross-reacted partially with each animal kidney enzyme except for the rabbit enzyme. Antigenic determinants of animal enzymes were variable from species to species and differed from those of the human enzyme in extent and specificity.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1982

Increased urinary excretion of angiotensin converting enzyme in patients with renal diseases.

We measured the activity of angiotensin converting enzyme (ED 3.4.15.1) in urine samples from normal subjects and patients with nephrotic syndrome and chronic glomerulonephritis. Urinary excretion of angiotensin converting enzyme in patients with nephrotic syndrome (1.58 +/- 0.50 (SD) units/day; n = 15) and chronic glomerulonephritis (1.01 +/- 0.45 units/day; n = 12) was significantly increased compared with normal subjects (0.38 +/- 0.10 units/day; n = 18). It was demonstrated that a high molecular weight form of the enzyme (more than 400000) was mainly excreted in urines from patients with nephrotic syndrome. After trypsin treatment, this form was altered to a low molecular weight form (290000). These two different forms of urinary angiotensin converting enzyme were compared with the enzyme purified from human kidney, and found to be identical with respect to Km values (2 mmol/l), pH optimum (pH 8.3), chloride ion dependency (0.8 mol/l), inhibitory effect of captopril (I50, 21 nmol/l), and behavior towards antiserum to human kidney angiotensin converting enzyme.

Adolescent↗
PubMed1982

Isolation of inactive renin from human plasma and its activation by proteolytic enzymes.

A completely inactive renin was isolated from normal human plasma by DEAE-Sepharose column chromatography, 70% ammonium sulfate precipitation and Blue-Sepharose column chromatography. This preparation had a specific activity of 122 ng ANG I/mg protein/h, when activated by trypsin. The inactive renin had an apparent molecular weight of 54,000 daltons as determined by gel filtration on Ultrogel AcA 44. Homogeneous human kidney renin (2.4 ng/100 micrograms of the inactive renin) activated the inactive renin. Trypsin (2 micrograms), highly purified human plasmin (70 micrograms) and homogeneous human plasma kallikrein (130 micrograms) activated the inactive renin by 100%, by 75% and by 17%, respectively. But highly purified human urinary kallikrein (up to 150 micrograms) did not activate the inactive renin at all. Trypsin-activated renin was a little different from natural plasma active renin with respect to molecular and kinetic properties. When the trypsin-activated renin was treated with human urinary kallikrein, its activity was unchanged, but its molecular weight, Km value, Ki value of pepstatin A and pH profile became identical with those of plasma active renin. On the other hand, renin-activated renin had the same kinetic properties of plasma active renin and human kidney renin, but had the same molecular weight (38,000) as human kidney renin that was smaller than natural plasma active renin (43,000).

Cold Temperature↗
PubMed1981

Isolation and characterization of angiotensin converting enzyme from human kidney.

Angiotensin converting enzyme [EC 3.4.15.1] was solubilized from the membrane fraction of human kidney cortex using trypsin and purified to homogeneity by DEAE-cellulose, hydroxylapatite and DEAE-Sephadex A-50 column chromatographies, preparative isoelectric focusing, and Sephadex G-200 gel filtration. The final recovery of the enzyme was 13.9%. The molecular weight of the enzyme was estimated to be 199,000 by a sedimentation equilibrium method. A value of 170,000 was obtained for the reduced and denatured enzyme by dodecylsulfate-polyacrylamide gel electrophoresis. The enzyme was a glycoprotein consisting of a single polypeptide chain with an isoelectric point of 5.10. Neutral sugar accounted for 13% per weight of the enzyme. The purified enzyme had a specific activity of 96.9 mumol/min/mg protein for hippurylhistidylleucine. The Km value, Kcat value and hydrolytic coefficient (Kcat/Km) of the enzyme for hippurylhistidylleucine were 2.0 mM, 545 s-1 and 273 mM-1 . s-1, respectively. Rabbit antibody against the human kidney converting enzyme inhibited the activities of the enzymes from human lung and serum as equally as that from human kidney, but not those from sheep, dog, or rat sera. The human kidney and lung converting enzymes were immunologically identical on double immunodiffusion analysis.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1981

Effects of angiotension II, thyroxine and estrogen on plasma renin substrate concentration and renin substrate production by the liver.

The effects of angiotensin II, thyroxine and 17 beta estradiol on plasma renin substrate concentration in rats and renin substrate production by perfused rat livers were investigated. The addition of angiotensin II (1-10 microgram) to the perfusion system did not affect the synthesis of renin substrate. After treatment with thyroxine (2.5 mg/kg/day), plasma renin substrate concentration, plasma renin activity, plasma aldosterone concentration and the rate of renin substrate synthesis were all significantly increased. 17 beta estradiol (2 mg) raised both plasma renin substrate concentration and the amount of renin substrate production by the liver. Isoelectric focusing profiles of renin substrate of liver perfusate and of plasma from estrogen-treated rats were different from that of liver perfusate from normal rats. But the profile of renin substrate in plasma was essentially similar to those to liver perfusates both in normal and estrogen-treated rats.

Angiotensin II↗
PubMed1981

Effects of a single administration of captopril on hemodynamics and serum angiotensin converting enzyme activity, plasma renin activity and plasma aldosterone concentration in hypertensive patients.

Hemodynamic responses and behaviors of the renin-angiotensin-aldosterone system to a single administration of captopril (50 mg) were studied in 16 hypertensive patients (essential hypertension, n = 10; renovascular hypertension, n = 3; primary aldosteronism, n = 2; Cushing's syndrome, n = 1). In 10 essential hypertensive patients, the immediate blood pressure reduction caused by decreased total peripheral resistance after the administration of captopril was observed without changes of cardiac output and heart rate. Serum angiotensin converting enzyme activity and plasma aldosterone concentration significantly decreased, whereas plasma renin activity significantly elevated 2 hours after the administration of captopril. The close relationship between the pretreatment value of plasma renin activity and the maximum decrease in mean blood pressure in 16 hypertensive patients suggests that the depressor response to a single administration of captopril could evaluate the degree of angiotensin II dependency in the maintenance of high blood pressure in various types of hypertension.

Adult↗
PubMed1980

Immunological characterization of human membrane-bound arylamidases from small intestine, lung, kidney, liver, placenta and renal cell carcinoma.

Anti-placental and anti-kidney membrane-bound arylamidase antibodies were prepared in rabbits. Both antibodies showed similar titration curves against both the original antigens, and the membrane-bound arylamidases partially purified from small intestine, lung, liver and renal cell carcinoma. Double immunidiffusion tests showed that six membrane-bound arylamidases were immunochemically indistinguishable.

Adenocarcinoma↗
PubMed1980

Angiotensin-converting enzyme in human prostate.

The activity of angiotensin-converting enzyme in human prostate was measured by spectrophotometric method using Hippuryl-L-histidyl-L-leucine (Hip-His-Leu) as substrate. Benign hypertrophic prostate had significantly higher concentration of angiotensin-converting enzyme (1.99 +/- 0.36 (S.E.M.) units/g of tissue, n = 13) than normal prostate (0.44 +/- 0.1 units/g of tissue, n = 5) (p less than 0.01). More than 80% of the enzyme activity occurred in soluble fraction of normal and hypertrophied prostates. Human prostatic angiotensin-converting enzyme, partially purified from benign hypertrophic prostates, had an apparent molecular weight of 290,000 and pI of 4.1. Optimum pH of the enzyme with KM value of 1.0 mmol/l was 7.8 in 0.1 mmol/l borate/sodium/carbonate buffer. The enzyme was competitively inhibited by captopril (Ki, 1.8 nmol/l).

Chlorides↗