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Biomedical subjects

H Kohno

Publications and source records attributed to H Kohno.

At least 397 records · Page 22Linked to original sources
PubMed1986

Immunoaffinity purification and characterization of leucine aminopeptidase from human liver.

Leucine aminopeptidase was purified from human liver cytosol to homogeneity, 1538-fold, with a yield of 84.4% by immunoaffinity chromatography. Increases in the activity and the stability of the enzyme were simultaneously observed during the purification procedure, suggesting the presence of some endogenous inhibitor in cytosol. The specific activity and Km value of the enzyme for L-leucine amide were found to be 58.00 mumol/min/mg of protein and 4.02 mM, respectively, at pH 8.0. The molecular weight of the enzyme was determined to be 360,000 by both polyacrylamide gradient gel electrophoresis and Sephadex G-200 gel filtration. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of native and dimethyl suberimidate cross-linked enzyme indicate that the native enzyme has two subunits of Mr 53,000 (a) and 65,000 (b) and is a hexamer arranged as a trimer of dimers (3 X (a X b)). The optimum pH was 10.5, and the enzyme was stable in the pH range from 7.5-8.5. The enzyme was activated by divalent metal ions, especially by Mg2+ and Mn2+, with no change in Km value. The enzyme was inhibited by metal-chelating agents, indicating it to be a metalloenzyme. Amastatin and bestatin strongly inhibited the enzyme, but leupeptin did not. The enzyme had a broad substrate specificity toward oligopeptides and amino acid amides but had little or no activity toward chromogenic substrates. The enzyme also could hydrolyze natural substrates contained in liver cytosol and accordingly produce many kinds of amino acids commonly found in proteins.

Cations, Divalent↗
PubMed1986

[Increased activity of sympatho-adrenomedullary system and decreased renal dopamine receptor content after short-term and long-term sodium loading in rats].

UNLABELLED: We investigated the effects of short-term and long-term sodium loading on the sympathoadrenomedullary system and renal dopamine receptor. Male Wistar rats (n = 30) were raised drinking 1% NaCl for four weeks. Urinary norepinephrine and epinephrine excretion (UNE and UE) were measured before and 1, 2, 4 weeks after sodium loading by the use of high pressure liquid chromatography with fluorescence spectrophotometer. Renal plasma membranes were prepared by the ultracentrifugation method, and maximal binding capacity (Bmax) and dissociation constant (Kd) of renal dopamine receptor were determined by Scatchard analysis using 3-H-spiperone. RESULTS: Sodium loading caused a slight but not significant decrease of free UNE after 1 and 2 weeks then clear increments of total (free + conjugated) UNE, free UE and total UE after 4 weeks. Bmax of renal dopamine receptor did not change after 1 and 2 weeks but significantly decreased after 4 weeks (before: 535.9 fmol/mg X protein, after 4 weeks: 327.2 fmol/mg X protein). Kd of renal dopamine receptor slightly elevated 1 week after sodium loading and then returned to the initial level. CONCLUSION: These data suggest that short-term sodium loading may suppress the sympathetic activity, but long-term sodium loading may increase the activity of the sympathoadrenomedullary system with the decrease of renal dopamine receptor concentration. Increased catecholamines and decreased renal dopamine after long-term sodium loading may contribute to sodium-dependent hypertension.

Adrenal Medulla↗
PubMed1986

Active uptake of testosterone by androgen receptors of hepatocellular carcinoma in humans.

Hepatocellular carcinoma (HCC) is more prevalent in males than it is in females, which has often been explained by the fact that alcoholism and chronic hepatitis B virus infection are more prevalent among males. The current studies, using biochemical and autoradiographic methods, verified that HCC contains higher concentrations of androgen receptors than the surrounding liver parenchyma and that extrinsically given testosterone are actively taken up by such tumors. These results may suggest that HCC is an androgen-dependent tumor and that, therefore, this tumor is more prevalent in males than it is in females.

Autoradiography↗
PubMed1986

[Role of renal dopamine receptor in the pathogenesis of hypertension after sodium loading].

UNLABELLED: The purpose of this study is to clarify the role of renal dopamine receptor in the pathogenesis of salt-dependent hypertension. Male Wistar rats were raised under three different conditions, control, 1% NaCl loading (NaCl) and 1% NaCl plus metoclopramide with a dose of 1.5 mg/kg daily (MC), for 2 weeks. Then, renal plasma membranes were prepared by ultracentrifugation method, and maximal binding capacity (Bmax) and dissociation constant (Kd) were determined by Scatchard analysis using 3H-spiperone. And plasma aldosterone and prolactin concentration in these three groups were measured by radioimmunoassay. RESULTS: Systolic blood pressure measured tail-cuff method significantly elevated in MC group, but not control and NaCl group. Bmax of renal dopamine receptor was 535.9 +/- 85.0 fmol/mg protein, 594.9 +/- 159.3 fmol/mg protein, 529.1 +/- 166.1 fmol/mg protein, in control, NaCl and MC group, respectively. Kd of renal dopamine receptor in NaCl group was significantly lower than control (p less than 0.05). Renal dopamine contents of NaCl and MC group were lower than control. There was a negative correlation between renal dopamine content and Bmax of renal dopamine receptor in NaCl group (r = -0.95, p less than 0.02). In MC group, plasma aldosterone concentration was slightly higher than control and NaCl group, but there was no differences in plasma prolactin concentration among these three groups.

Aldosterone↗
PubMed1986

Studies on the 67Ga uptake mechanism by Ehrlich ascites tumor cells.

In order to obtain more information concerning the mechanism of Gallium (67Ga) accumulation in malignant tissue, an investigation was carried out using Ehrlich ascites tumor cells. Chlorpromazine, a phospholipid stabilizer decreased the uptake of 67Ga and Calcium 45 (45Ca) by the cells at low dose, but increased them at high dose. On the other hand, the uptake of both radionuclides by the cells was inhibited by ruthenium red, a Ca ATPase inhibitor in a dose dependent manner. The time course of 67Ga and 45Ca uptake were quite different from each other. Moreover, the subcellular distribution patterns of 67Ga and 45Ca were also different from each other; 67Ga accumulated in the lysosomal fraction and 45Ca mainly in the mitochondrial fraction. These results suggest that there may be a commonality for 67Ga and 45Ca uptake by the tumor cells, whereas the behaviour of these two radionuclides in the cells is dissimilar.

Animals↗
PubMed1986

Characterization of experimental ischemic brain edema utilizing proton nuclear magnetic resonance imaging.

Correlations between T1 and T2 relaxation times and water and electrolyte content in the normal and ischemic rat and gerbil brains were studied by means of both nuclear magnetic resonance (NMR) spectroscopic and imaging methods. In the spectroscopic experiment on excised rat brains, T1 was linearly dependent on tissue water content and T2 was prolonged in edematous tissue to a greater extent than expected by an increase in water content, showing that T2 possesses a greater sensitivity for edema identification and localization. Changes in Na+ and K+ content of the tissue mattered little in the prolongation of relaxation times. Serial NMR imaging of gerbil brains insulted with permanent hemispheric ischemia offered early lesion detection in T1- and especially T2-weighted images (detection as soon as 30 min after insult). The progressive nature of lesions was also imaged. Calculated T1 and T2 relaxation times in regions of interest correlated excellently with tissue water content (r = 0.892 and 0.744 for T1 and T2, respectively). As a result, detection of cerebral ischemia utilizing NMR imaging was strongly dependent on a change in tissue water content. The different nature of T1 and T2 relaxation times was also observed.

Animals↗
PubMed1986

Phorbol ester-induced regulation of transferrin receptors in human leukemia K562 cells.

The treatment of human leukemia K562 cells with 12-0-tetradecanoyl phorbol-13-acetate (TPA) caused a decrease of transferrin receptors. The mechanism of the decrease of the receptors with TPA has been investigated. In cells incubated with TPA, the rate of biosynthesis of transferrin receptors was reduced to 10-20% of that in untreated cells. Pulse-chase experiments showed that turnover of the receptors in TPA-treated cells was accelerated over that in untreated cells. These results indicated that the decrease of transferrin receptors in TPA-treated cells was caused by reduced biosynthesis and accelerated degradation of the receptors.

Cell Line↗
PubMed1986

[Effects of iodine-enriched egg (IE-egg) on nasal allergy: basic and clinical investigations].

The effect of iodine-enriched egg (IE-egg) on nasal allergy was investigated using an experimental allergic model. In addition, the effect of IE-egg was investigated using patients with yearly nasal allergy. IE-egg could suppress the leakage of pontamine sky blue dye in the experimental allergic model. beta-Glucuronidase activity in the perfusate was suppressed with the ingestion of IE-egg. The symptoms of the patients with yearly nasal allergy were mitigated by the ingestion of IE-egg. beta-Glucuronidase activity in the pituita of nasal allergic patients tended to be decreased.

Alkaloids↗
PubMed1986

[Effects of cepharanthine on experimental nasal allergy].

The anti-allergic actions of cepharanthine were examined using experimental nasal allergy rats (rhinitis models). In the actively sensitized rhinitis models, leaks of pontamine sky blue (PSB) dye in the perfusate of the nasal cavity were suppressed by cepharanthine treatment. Leaks of PSB dye in the perfusate were also suppressed by ketotifen treatment. beta-Glucuronidase activity in the perfusate was lower in the cepharanthine group and in the ketotifen group. In the passively sensitized rhinitis models, leaks of PSB dye in the perfusate were suppressed by cepharanthine treatment. Leaks of PSB dye in the perfusate in the ketotifen group were also suppressed. However, beta-glucuronidase activity was not different among the three groups. Cepharanthine (0.025-25 mg/kg body weight) and ketotifen (0.1-10 mg/kg body weight) inhibited leaks of PSB into the perfusate in a dose-dependent manner. These results suggest that cepharanthine may be clinically effective for treating patients with nasal allergy, and its anti-allergic mechanism may be the same as that of ketotifen.

Alkaloids↗
PubMed1986

Two adult familial cases of selective hypoaldosteronism due to insufficiency of conversion of corticosterone to aldosterone.

A 57-year-old woman (case 1) and her daughter aged 29 (case 2) with hyperkalemia exhibited subnormal plasma aldosterone (ALD) in the face of elevated plasma renin activity. Their physical findings were normal. Their arterial blood gas analysis showed that metabolic acidosis and renal function of these cases were slightly impaired. Urinary 17-OHCS and 17-KS excretions in these cases were normal. Baseline levels of corticosterone (B) and 18-hydroxycorticosterone (18-OH-B) were clearly elevated. Plasma deoxycorticosterone (DOC), B and 18-OH-B as well as cortisol remarkable increased after ACTH injection, but the increase in plasma ALD was very small. Angiotensin II infusion in case 1 resulted in a clear rise in plasma 18-OH-B but in slight depletion of B, and no increase in ALD. 9-alpha-fludrocortisone acetate treatment was performed in case 1. Serum potassium was normalized and blood pressure elevated from 82/52 to 120/78 mmHg. Arterial blood gas analysis was corrected. We concluded that these two cases with subnormal plasma ALD and hyperreninemia may exist as a congenital and familial abnormality of the final step of aldosterone boisynthesis due to the impairment of the conversion of B to ALD.

Adrenocorticotropic Hormone↗
PubMed1986

Human beta-endorphin and beta-lipotropin levels in maternal and fetal plasma and amniotic fluid.

We measured beta-endorphin (beta-EP) and beta-lipotropin (beta-LPH) levels in human maternal and fetal plasma and amniotic fluid, simultaneously. It appeared evident that maternal circulating levels of beta-EP (n = 11, 163.9 +/- 12.9 pg/ml, mean +/- S.E.) and beta-LPH (n = 11, 413.0 +/- 25.9 pg/ml) at delivery were significantly (p less than 0.01) higher than those of maternal plasma at term (beta-EP; n = 4, 18.3 +/- 2.1 pg/ml, beta-LPH; 213.4 +/- 24.3 pg/ml) and those of amniotic fluid (beta-EP; n = 5, 8.5 +/- 1.2 pg/ml, beta-LPH; 215.1 +/- 44.9 pg/ml). Fetal beta-EP levels (n = 11, 79.1 +/- 5.8 pg/ml) were significantly (p less than 0.01) higher than those of amniotic fluid. These data suggest that the origin of amniotic fluid beta-EP may be an increased synthesis in the maternal and fetal pituitary gland but not in the placenta.

Amniotic Fluid↗
PubMed1986

Receptor-mediated heme uptake from hemopexin by human erythroleukemia K562 cells.

Using human erythroleukemia K562 cells, existence of receptors for hemopexin has been investigated. Hemopexin was bound to the cells in saturable, time- and temperature-dependent manner. The cells exhibited approximately 8,400 binding sites/cell for hemopexin and apohemopexin. The dissociation constants (Kd) for hemopexin and apohemopexin were 4.79 nM and 10.8 nM, respectively. Specific binding of labeled hemopexin was inhibited with increasing concentrations of unlabeled hemopexin and apohemopexin, but unaffected by transferrin and serum albumin. Heme bound to hemopexin was incorporated into the cells at 37 degrees C, but not at 4 degrees C. These results indicate that heme in hemopexin was taken up by K562 cells via the receptors for hemopexin.

Cell Line↗
PubMed1986

[Urinary kallikrein quantity and activity of normal pregnant women and toxemia patients in third trimester].

In this study, urinary kallikrein quantity and activity were measured by the kallikrein direct RIA and kininogenase activity with human low molecular weight kininogen in 32 non pregnant healthy women, 20 normal 3rd trimester pregnant women and 18 3rd trimester hypertension type toxemia patients. There was no significant difference in urinary kallikrein quantity between non pregnant women (n = 32, 64.0 +/- 6.3 micrograms/day, mean +/- SE) and normal pregnant women (n = 20, 68.1 +/- 10.1 micrograms/day). There was a significant difference (p less than 0.001) between non pregnant women and toxemia patients (n = 18, 22.5 +/- 3.3 micrograms/day). There was a significant difference (p less than 0.001) between toxemia patients and normal pregnant women. There was a significant difference (p less than 0.05) in urinary kallikrein activity between non pregnant women (n = 32, 496.2 +/- 57.2 micrograms kinin/day) and normal pregnant women (n = 20, 319.5 +/- 48.1 micrograms kinin/day). There was a significant difference (p less than 0.0001) between non pregnant women and toxemia patients (n = 18, 82.6 +/- 13.6 micrograms kinin/day). There was a significant difference (p less than 0.01) between normal pregnant women and toxemia patients. There were no correlation in both urinary kallikrein quantity and activity between severe type toxemia patients (systolic blood pressure greater than or equal to 160mmHg or diastolic blood pressure greater than or equal to 110mmHg) and mild type toxemia patients (160mmHg greater than systolic blood pressure greater than or equal to 140mmHg and 110mmHg greater than diastolic blood pressure greater than or equal to 90mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗