Sensitive direct radio-immunoassay for human renin

A sensitive direct human renin radio-immunoassay has been developed for clinical use. The antigen source was human renal renin purified from Haas' preparation by pepstatin-C6-sepharose affinity chromatography, this was used to prepare a specific human renin antibody. The radio-immunoassay was performed by the double antibody technique using the delayed tracer addition method. Standard curves were obtained over the range 0.2-8.0 ng/ml. Dilution curves of human renal renin and human plasma were superimposable on the standard curve. Both active and inactive renin were detected by this method, and measurements correlated well with total renin activity after trypsin activation. Intra- and inter-assay coefficients of variance were 4.6% and 5.1%, respectively. Renin concentration was higher in patients with renovascular hypertension (1.97 +/- 0.38 ng/ml, mean +/- s.d., n = 10, P less than 0.01), but lower in primary aldosteronism (0.66 +/- 0.16 ng/ml, n = 13, P less than 0.01) compared with essential hypertension (1.38 +/- 0.34 ng/ml, n = 12). This method provides a new tool for the investigation of the renin-angiotensin system in man.

A new sensitive direct radioimmunoassay for human plasma renin and its clinical application

We developed new sensitive direct radioimmunoassay for human plasma renin. Renin was purified from Haas' preparation utilizing a pepstatin-C6-Sepharose affinity chromatography. Antiserum, prepared by immunizing rabbits with the purified renin, was used for the direct radioimmunoassay at a final dilution of 1:30,000. The antibody was specific for human renal and plasma renin, but did not cross-react with cathepsin D, trypsin, or renins of mouse, dog, and rat. Radioimmunoassay was performed by the double antibody technique using the delayed tracer addition method. In this method, a standard curve was obtained over a range from 0.2 to 8.0 ng/ml. The values from our assay correlated well with total renin activity measured as the generation rate of angiotensin I after trypsin activation (r = 0.78, p less than 0.01), but correlated weakly with active renin activity. This finding disclosed that both active and inactive renin were detected by this method. In normal participants, plasma renin concentration determined by direct radioimmunoassay was increased by standing and furosemide injection. The plasma renin concentration determined by direct radioimmunoassay of patients with essential hypertension (0.7 to 1.7 ng/ml) was not significantly different from values in normal controls (0.8 to 1.9 ng/ml). The values were higher in patients with renovascular hypertension (1.6 to 2.7 ng/ml), malignant hypertension (2.8 to 3.4 ng/ml) and Bartter's syndrome (1.8 to 2.5 ng/ml), but lower in patients with primary aldosteronism (0.4 to 0.8 ng/ml) than in normal controls. This newly developed radioimmunoassay for human renin was sensitive enough to estimate the levels of renin in plasma of patients with low renin hypertension. It provides a new tool for the understanding of the renin-angiotensin system under various clinical conditions.

Structure of angiotensin II-binding site probed with diaminoalkanes

The nature of the hormone-binding site of detergent-solubilized angiotensin II receptor from the bovine adrenal cortex has been characterized using diaminoalkanes. Their affinity for the hormone-binding site showed a dramatic alteration depending on their chain length; at the hexamethylene stage, a maximum and competitive inhibition was observed. These results indicate that the angiotensin II receptors have a definite hydrophobic binding groove limbed with diagonally located two negative charges, and those hydrophobic and electrostatic forces may play an important role in the proper register between the receptor and hormone.

[Study on the concentration of FT-207 and 5-FU in serum, lymph nodes and tissues after administration of FT-207 suppositories]

In 21 cancer patients receiving administration of FT-207 suppositories, we studied the concentration of FT-207 and 5-FU in the blood before surgery, and in the blood and tissues-tumor, normal and lymph node-sampled during surgery. These 21 cases were comprised of 12 cases of stomach cancer, 1 case of lymphosarcoma, 4 cases of rectal cancer, 2 cases of sigmoid cancer and 2 cases of breast cancer. Two hours after administration, the concentration of 5-FU reached its highest level and continued to maintain a level at which it could be expected to bring about clinical results even after four hours. The concentration of 5-FU in tumors and lymph nodes was high, especially in tumors compared with normal tissue (p less than 0.01). No difference could be found in the concentrations of FT-207 and 5-FU in serum and tissues from each 12 cases of stomach cancer, not only between of the early cancer and advanced cancer but also between patients more than 60 years old and those under 60 years old. No side-effects occurred in any case during suppository administration.

An improved method for determination of active and total renin concentration in human plasma using an excess of sheep substrate

A method for measurement of renin concentration (PRC) in human plasma has been developed and validated experimentally and theoretically. Like most of the previous methods, the present method is based on a radioimmunoassay of angiotensin I generated during incubation of plasma with an excess of renin substrate. In the present study we used, as the substrate, sheep angiotensinogen partially purified from anephric sheep plasma by ammonium sulfate fractionation and pepstatin-aminohexyl-agarose chromatography. The advantage of using sheep substrate is that it has an exceptionally high affinity for human renin. The partially purified substrate, which contained no detectable renin activity, improved the sensitivity, allowing quantification of renin in low-renin plasma. Possible interfering influences of plasma proteins on the radioimmunoassay were eliminated by the introduction of a simple deproteinization step. For determination of total renin concentration (TRC), inactive renin was activated by exposing plasma to low pH or trypsin. Normal values of PRC and TRC after careful selection of assay conditions were 2.9 +/- 0.4 and 33.9 +/- 6.1 ng angiotensin I X ml-1 X h-1, respectively. As an illustrative example of usefulness of the assay, PRC determination of a patient with a ectopic renin-secreting tumor is presented.

Double contrast arthrography of the knee in acute injury of the medial collateral ligament

The double contrast arthrography with horizontal beam method was carried out in 133 cases with acute medial collateral ligament injuries of the knees and its findings were compared with those from arthroscopy and/or surgery. The double contrast arthrography demonstrated the level of the rupture in capsular ligament in relation to the meniscal attachment, accompanying meniscal tear or detachment, and intrusion of the free end of the torn ligament into the joint. It also revealed the magnitude of the medial instability and facilitated to distinguish an isolated from a combined injury. A therapeutic regime can be proposed on the basis of the arthrographic findings. We conclude that the double contrast arthrography for the acute injuries of the medial collateral ligament is indispensable in the selection of the optimal treatment.

A novel purification method of human renin

Human renal renin was isolated from a partially purified preparation, Haas' preparation step 5 material, with a remarkably high yield of 28% by a newly developed method. This method consisted of only four steps including affinity chromatography on pepstatin-aminohexyl-agarose, chromatofocusing, gel filtration and DEAE-chromatography after the initial extraction and concentration. This method enabled us to obtain pure human renin without another affinity column used by other investigators. Pure human renin had a molecular weight of 40,000 daltons as estimated by gel filtration and sodiumdodecylsulfate-polyacrylamide gel electrophoresis. The pI of purified renin was 5.6.

The effect of oxygen on the development of atherosclerosis in WHHL rabbits

The effect of hyperoxic or hypoxic inhalation on blood lipid levels and on the development of atherosclerosis was studied in young male WHHL rabbits. They were exposed to ordinary room air containing different concentrations of oxygen: 6 animals were exposed to 40% oxygen (hyperoxia group) or 5-10% oxygen (hypoxia group) for 5 h a day, 5 days a week for 8 weeks. Four control rabbits inhaled ordinary room air. The following results were obtained. (1) The severity of aortic lesions significantly decreased in the hyperoxia group and increased in the hypoxia group, when these two groups were compared. However, both hypoxic and hyperoxic groups did not statistically differ from the control. (2) Plasma cholesterol levels were not changed either by hyperoxic or hypoxic inhalation. (3) Plasma triglyceride levels were elevated only in the hypoxia group, with significant differences from the values in both control and hyperoxia groups. (4) There was no significant correlation between mean plasma lipid level and severity of aortic lesions. From these results, we conclude that hyperoxic or hypoxic inhalation respectively regresses or aggravates the development of atherosclerotic lesions, not by an indirect action on blood lipid concentrations but by a direct action on the vascular wall.

Diurnal profile of gallbladder size in diabetic patients: ultrasonographic evaluation of diabetic neurogenic gallbladder

The diurnal change of gallbladder size was clearly measured with a real time ultrasonography. To visualize the gallbladder, 21 diabetic patients and 11 healthy subjects were scanned right subcostally in the supine position nine times between 8:00 a.m. and 8:00 p.m. Photographs of the images were produced on Polaroid film, and the area of gallbladder was calculated. The diurnal changes of the gallbladder size were expressed as the percentage of the size measured at 8:00 a.m. after an overnight fast. The gallbladder in normal control started contracting immediately after breakfast and reached 57.2 +/- 7.6% at 9:00 a.m. In the diabetic patients with and without autonomic neuropathy the gallbladder contracted to 80.9 +/- 14.5% and 72.4 +/- 14.8%, respectively, at 9:00 a.m. while the nadir of the diurnal profile curve in healthy subjects was 24.5 +/- 3.6% at 3:00 p.m., in the diabetic patients with and without autonomic neuropathy those were 57.7 +/- 6.1% at 6:00 p.m. and 41.3 +/- 8.3% at 8:00 p.m., respectively. This implies that the gallbladder contraction was delayed and poor in diabetic patients. In this paper, the gallbladder tonicity index is proposed, which is useful for the easy evaluation of autonomic state of gallbladder in diabetes mellitus.

Disturbances of the alimentary tract motility and hypermotilinemia in the patients with diabetes mellitus

Lower esophageal sphincter pressure (LESP), gastric emptying, small bowel transit time and plasma motilin levels were measured in diabetics and normal subjects in order to investigate the disturbances of the alimentary tract motility and the participation of motilin in these motility disorders. Hypermotilinemia was observed in all diabetics with or without autonomic neuropathy. Low response of LESP to tetragastrin found in diabetics with autonomic neuropathy could not be explained by motilin. Gastric emptying was highly correlated with fasting plasma motilin levels and a significantly accelerated gastric emptying observed in diabetics without complications or diabetics with diarrhea was considered to be due to hypermotilinemia. On the contrary, no significant correlation was observed between small bowel transit time and plasma motilin levels, suggesting no participation of endogenous motilin in the regulation of small bowel transit.

[Significance & treatment of abnormal blood viscosities in pre-eclamptic patients (author's transl)]

Blood viscosity, a blood flow volume determinant, is one of the primary indicators of the state of pregnancy. The viscosity of peripheral veins was measured using a cone-plate viscometer (share rate 150 sec-1, 375 sec-1) and the results were utilized in comparisons between control and experimental groups to determine their importance to pre-eclamptic patients. Compared with values of 11 non-pregnant subjects (3.614 cp), 165 normal pregnancy cases had lower measurements during the entire term of pregnancy. The viscosity of these normal pregnant subjects decreased up to the 24th week, and increased thereafter. It is hypothesized that this results from the increased plasma volume of pregnant women. In severe pre-eclamptic subjects (3.508 cp), viscosity was significantly higher than in normal pregnancy cases. The natural decrease in peripheral blood flow resulting from elevated viscosity threatens the lives of both mother and fetus. Further analysis of clinical symptoms placed these 31 preeclamptic subjects in the conventional categories of hypertensive, proteinuric, and edematic. Viscosity measurements were highest for hypertensive (4.0059 cp), and lowest for edematic (2.7615 cp) and of intermediate value for proteinuric (3.2122 cp). To normalize these viscosities, the administration of dextran infusion therapy to hypertensive subjects and short-term furosemide therapy to edematic subjects was undertaken and brought considerable beneficial results.

[Studies on the physiological changes of blood coagulation factor XIII during pregnancy and their significance (author's transl)]

We measured the blood coagulability in pregnancy. Factor XIII, that showed unusual variations in these experiment, was investigated for its biological significance. The results are summarized as follows: 1) Blood coagulation factors XII, IX, VIII, VII and X, prothrombin and plasminogen showed a increasing tendency as the course of pregnancy. These was not very much change in factor V and plasmin activity during pregnancy. Factor XI showed a decreasing tendency. The further dramatic variation appeared in each coagulation factor at the onset of labor. 2) With regards to the factor XIII, XIII-S a carrier protein was inclined to increase from the value of 94.0 +/- 16.0% before pregnancy and reached the value of 109 + 16.3% at the last stage of pregnancy, while XIII-A an active site showed a decreasing tendency from 97.5 + 17.5% before pregnancy to 67.0 + 12.0%. 3) In placenta homogenate XIII-A was observed, but XIII-S absent. In retro-placental blood XIII-S was observed, but no XIII-A was seen. No significant difference between uterine venous blood and maternal peripheral blood was recognized. 4) The placental localization of XIII-A was investigated by the methods of fluorescent antibody technique and enzyme labeled antibody technique. XIII-A appeared in syncitiotrophoblast, but was not found in stroma, vessel wall and fetal side. In regards to decidua region its presence was not confirmed.

The release of monovalent counterions by addition of divalent countemons to aqueous solutions of maleic acid copolymer

Divalent cation binding and the release of monovalent cations accompanying the cation binding were experimentally studied by ion-selective electrode methods in aqueous solutions of copolymer of maleic acid and ethyl vinyl ether. It was found that in the process of Ca2+ addition, all the Ca2+ added was bound to polyions and the initially condensed Na+ was released in proportion to the concentration of the added Ca2+ up to the critical concentration of added Ca2+ at which the condensation of Ca2+ ceases. Values of the structural charge density parameter xi(s), were determined from the end-points of condensation of Ca2+. The process of Na+ release by adding Ca2+ was analyzed on the basis of the counterion condensation theory by using these xi(s) values. In addition, the relationship between the activity coefficient gamma-- of Ca2+ and degree of neutralization alpha in salt-free solutions was obtained from the Manning theory. Agreement between the calculated and experimental values was excellent in both cases.

Studies on the preventive method of lowered ventricular fibrillation threshold during experimental acute myocardial infarctions. A comparison between disopyramide phosphate and lidocaine

This study was performed to investigate the prophylactic effect of disopyramide phosphate on ventricular fibrillation in acute myocardial infarction. Lidocaine and disopyramide phosphate were compared in terms of their effects on the lowered ventricular fibrillation threshold in experimental myocardial infarction produced by coronary ligation in dogs. The following results were obtained: 1) The effect of lidocaine i.v. + infusion appeared promptly and the ventricular fibrillation threshold exceeded control levels from 45 min onwards (p less than 0.01). 2) The i.m. injection of lidocaine was effective in a dose of 10 mg/Kg. The minimally effective blood level was 1.7 mcg/ml. 3) Disopyramide phosphate 5 mg/Kg i.v. produced a tendency towards recovery from 15 min onwards. After 30 min, the ventricular fibrillation threshold was significantly higher than control (p less than 0.01). 4) Disopyramide phosphate 5 mg/Kg i.m. was initially effective after 45 min. The effect was significant from 1 hour and 30 min onwards, compared with control (p less than 0.01). The minimally effective blood level was 2.4 mcg/ml. 5) Disopyramide phosphate 2 mg/Kg i.m. produced a tendency towards recovery but the difference from the control was not significant. 6) In equivalent i.m. doses, disopyramide phosphate tended to be more potent than lidocaine in increasing the ventricular fibrillation threshold. 7) In the aforementioned doses, disopyramide phosphate did not cause any marked changes in PQ interval or QT time in ECG. These results suggest that the intramuscular injection of disopyramide phosphate is a hopeful clinical treatment to prevent ventricular fibrillation in the very early stages of acute myocardial infarction.

Regional changes in cardiac structural proteins in myocardial infarction: biochemical and histologic correlates

1. Quantitative analysis of structural proteins from a minute amount of myocardial tissue was performed from 10 mu thick cardiac tissue slices weighing 2 to 5 mg by the extraction in glycerol solution and by sodium dodecylsulfate (SDS) gel electrophoresis, and these changes were compared with the histologic alterations in the striated structure of the adjacent cardiac slices in the experimental myocardial infarction in the dog. 2. Approximately 69 micrograms of structural proteins were obtained from 1 mg of the normal heart muscle. In the central portions of the myocardial infarction, reductions in myosin heavy chain (HC), light chain (LC) 1 and alpha-actinin were observed at 12 to 24 hours after the coronary occlusion followed by the decrease in myosin LC 2 at 48 hours. Those changes became intense at 72 hours to 7 days, but restored gradually at 14 to 28 days. 3. Alterations in the striated structure of cardiac muscle fibers of the adjacent tissues slices were found simultaneously with the changes in structural proteins. At 12 to 24 hours after the coronary ligation increase in eosinophilia and overstretch of cross-striation were observed. The findings of coagulation necrosis, loss of striation, fragmentation, swelling of A-band, etc. of the infarcted fibers were markedly observed at 48 hours to 7 days, but the histologic restoration of cardiac fibers was found with the recovery of the infarcted tissue at 14 to 28 days after the coronary ligation. 4. Changes in the compositions of structural proteins corresponded well to the alterations in the striated structure in chronology and in quantity.

An electrochemical study of the iron storage protein, ferritin

The electrochemical behavior of iron storage protein, ferritin (molecular weight 700 000) was studied by pulse polarography, cyclic voltammetry and 'potentiometry' monitored by colorimetry. Comparison between in vivo and voltammetric redox reactions of the ferritin Fe(III) core and thermodynamic E'0 values for native ferritin are described.