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Biomedical subjects

N Kawasaki

Publications and source records attributed to N Kawasaki.

At least 19 recordsLinked to original sources
PubMed1991

Determination of non-protein-bound iron in rat tissue by ion chromatography with electrochemical detection.

A new, rapid, sensitive, and specific method combining ion chromatography with electrochemical detection was developed for measuring non-protein-bound Fe(II) and Fe(III) in biological samples. The procedure was based on the separation of the iron-diethylenetriaminepentaacetic acid complex formed directly on the chromatographic column with anion-exchange resin followed by electrochemical detection. The method enabled more than 0.5 microM Fe(II) and Fe(III) to be determined for injection volumes of 10 microliters. This method was applicable for the determination of Fe(II) and Fe(III) in ultrafiltrates of the rat liver cytosolic fraction. It was found that release of iron from iron-bound proteins was pH dependent and that non-protein-bound iron in the tissues was determined in a ferrous state at low pH values.

Animals↗
PubMed1991

[The influence of aging on the development of rat galactosemic cataract].

In order to investigate the effect of age on the rat galactosemic cataract, 3, 6, 12 and 24-week-old rats were fed with a 50% galactose diet. The cataractous lenses were observed by light microscopy, and the amount of galactitol measured. All rats fed with 50% galactose developed cataracts in the equatorial region. However, the morphological and biochemical development of the galactose cataract in old rats was slower than in young rats. These results suggested that older diabetic patients are less likely to develop diabetic cataract than younger patients.

Aging↗
PubMed1990

Conservative management of cerebellar hemorrhage in pregnancy.

A case of cerebellar arteriovenous malformation (AVM) during pregnancy is reported. A 26-year-old primigravida had cerebellar hemorrhage at 32 weeks of gestation. She was conservatively controlled until term with a good outcome accomplished by elective cesarean section. AVM in the left cerebellar hemisphere was confirmed by angiography after delivery and successfully removed. Here we present a review of AVM during pregnancy and a few case reports of cerebellar AVM-complicated pregnancy published in available literatures.

Adult↗
PubMed1990

[Studies on the quality of enzyme preparations (XI)--Kallidinogenase preparations].

Qualitative tests of 22 kinds of commercially available kallidinogenase preparations were carried out by the enzymological method. These preparations consisted of 16 kinds of tablets, 5 kinds of capsules and 1 kind of ampoule. One sample of tablet showed kallidinogenase activity less than 80% of the labeled amount by spectrophotometry, pH stat and kinin-liberating methods. All other preparations were found to have 90-120% 120% of the labeled amount by spectrophotometry using S-2266 as the substrate. Other enzymes, i.e. kininase, trypsin and chymotrypsin were found as impurities, but the cntants were very low.

Dosage Forms↗
PubMed1989

Characterization of aldose reductase and aldehyde reductase from rat testis.

Aldose reductase (alditol:NAD(P)+ 1-oxidoreductase, EC 1.1.1.21) and aldehyde reductase (alcohol:NADP+ oxidoreductase, EC 1.1.1.2) were purified to a homogeneity from rat testis. The molecular weights of aldose reductase and aldehyde reductase were estimated to be 38,000 and 41,000 by SDS-polyacrylamide gel electrophoresis, and the pI values of these enzymes were found to be 5.3 and 6.1 by chromatofocusing, respectively. Aldose reductase had activity for aldo-sugars such as xylose, glucose and galactose, whereas aldehyde reductase was virtually inactive for these aldo-sugars. The Km values of aldose reductase for aldo-sugars were relatively high. When a correction was made for the fraction of aldo-sugar present as the aldehyde form, which is the real substrate of the enzyme, the Km values were much lower. Aldose reductase utilized both NADPH and NADH as coenzyme, whereas aldehyde reductase utilized only NADPH. Aldose reductase was activated significantly by sulfate ion, while aldehyde reductase was little affected. Both enzymes were inhibited strongly by the known aldose reductase inhibitors. However, aldehyde reductase was in general less susceptible to these inhibitors when compared to aldose reductase. Both aldose reductase and aldehyde reductase treated with pyridoxal 5-phosphate have lost the susceptibility to aldose reductase inhibitor, suggesting that in these two enzymes aldose reductase inhibitor interacts with a lysine residue.

Alcohol Dehydrogenase↗
PubMed1989

Primary structure of an N-linked sugar chain derived from glucoamylase of Rhizopus niveus.

The primary structure of the N-linked sugar chain of Rhizopus niveus glucoamylase (major component) was investigated. The carbohydrate moiety was released from the polypeptide backbone by Flavobacterium sp. endo-beta-N-acetylglucosaminidase digestion. Studies using the method of exoglycosidase digestion of the fluorescent pyridylamino derivative, gel-permeation chromatography on Bio-Gel P-4 and 400-MHz 1H-NMR spectroscopy revealed that the most abundant structure is (Man)8-GlcNac-ol.

Aminopyridines↗
PubMed1989

Mechanism of testicular atrophy induced by di-n-butyl phthalate in rats. Part 1.

Repeated oral doses of di-n-butyl phthalate (DBP) to male rats caused a decrease in testicular fructose and glucose and a sloughing of the germ cells on the first day of treatment. On day 2, more severe sloughing was seen and was accompanied by decreases in testicular iron and zinc levels and increases in the level of inositol and cholesterols. The sloughing was followed by atrophy, accompanied by dissociation of the germ cells from the Sertoli cells and reduction of triglycerides, cholesterols and phospholipids containing choline and ethanolamine residues in the testis.

Aldehyde Reductase↗
PubMed1989

A serum lectin (mannan-binding protein) has complement-dependent bactericidal activity.

Serum mannan-binding protein (MBP), which is a lectin specific for mannose and N-acetylglucosamine and is known to activate complement via the classical pathway, has been revealed to have a complement-dependent bactericidal activity, as tested on rough strains of Escherichia coli, K-12 and B. The bacteria, which had been sensitized with purified human serum MBP in the presence of Ca2+, followed by incubation with guinea pig complement, showed a marked decrease of colony forming ability compared with those not sensitized with the lectin. The bactericidal effect depended on the concentrations of the lectin and complement. The C4-dependency of the reaction indicated that the complement-dependent bactericidal action by MBP is expressed through the classical pathway. The bacteria were aggregated by the lectin. Scatchard plot analysis of 125I-labeled MBP binding to the bacteria showed that the dissociation constant (Kd) and the maximum binding capacity were 6 x 10(-9) M and 30,000 molecules of MBP per cell, respectively. The binding was inhibited by mannose, N-acetylglucosamine, N-acetylmannosamine, L-fucose, manno-heptulose, and sedoheptulose, suggesting that MBP recognized L-glycero-D-manno-heptose and N-acetylglucosamine constituting the core oligosaccharide of the E. coli K-12 cell wall, and L-glycero-D-manno-heptose for E. coli B. These findings suggest the physiological significance of the serum lectin in host defense, being consistent with the avirulence of E. coli rough strains in mammals.

Animals↗
PubMed1989

[Urokinase Reference Standard of National Institute of Hygienic Sciences (Control 881)].

The National Institute of Hygienic Sciences Standard for Urokinase (Control 881) was established in collaboration with five laboratories. This standard contains 1100 international units of urokinase and 1.17 mg of human serum albumin in each ampoule. Urokinase used for the standard is constituted of 1 part of high molecular weight species (M. W. 54000) and 4 parts of low molecular weight species (M. W. 33000).

Drug Stability↗
PubMed1989

[Studies on the quality of enzyme preparations (X)--urokinase preparation].

Urokinase preparations were investigated with a view to comparing their quality by enzymological methods. These studies were carried out on 10 kinds (9 kinds of preparations produced from human urine and one kind of preparation produced from tissue culture) of commercially available urokinase preparations. The potency of all preparations assayed by the two-stage method were found to be within the range of permissible content. Because there are two molecular weight types (molecular weight: 54,000 and 33,000) of urokinase. the distribution of two types of urokinase in preparations was determined. Human urine urokinase preparations contained mainly the high molecular weight type urokinase (over 90%), and the tissue culture preparation contained the low molecular weight type urokinase alone.

Chromatography, High Pressure Liquid↗
PubMed1988

Effects of pregnancy and hormone treatments on pressor response to angiotensin II in conscious rats.

Pressor responses to graded doses of angiotensin II in conscious rats were significantly reduced on days 13 and 19 of pregnancy compared with those in nonpregnant rats. To study the hormonal regulation of this altered pressor response to angiotensin II during pregnancy, we administered estradiol, progesterone, and human chorionic gonadotropin to nonpregnant rats. In ovariectomized rats no effect of estradiol on the pressor response to angiotensin II was found, but injections of progesterone with or without estradiol pretreatment significantly reduced the pressor response to angiotensin II. In intact rats human chorionic gonadotropin induced elevation of endogenous progesterone levels, followed by a significant decrease in the pressor response to angiotensin II. Injection of estradiol after human chorionic gonadotropin pretreatment produced a significant elevation in the pressor response to angiotensin II. These findings indicate that the decrease in angiotensin pressor response in pregnant rats is mediated mainly by progesterone rather than by estrogen.

Angiotensin II↗
PubMed1987

Serum lectin with known structure activates complement through the classical pathway.

Serum mannan-binding protein (MBP), a lectin specific for mannose and N-acetylglucosamine, was revealed to activate the complement system as measured by passive hemolysis using sheep erythrocytes coated with yeast mannan. In contrast, rat liver MBP, which shares many properties in common with serum MBP, could not activate complement at all. The activation by serum MBP was inhibited effectively by the presence of haptenic sugars and dependent absolutely upon the presence of C4, indicating that the activation is initiated by the sugar binding activity of MBP and proceeds through the classical pathway. The 25 NH2-terminal amino acid sequence of rat serum MBP determined in this study was completely matched with that of MBP-A deduced from cDNA sequence by Drickamer et al. (Drickamer, K., Dordal, M. S., and Reynolds, L. (1986) J. Biol. Chem. 261, 6878-6887), revealing that MBP-A is in fact identical with serum MBP. On the basis of the knowledge of primary structures and physicochemical properties of rat serum and liver MBPs, a possible mechanism of the complement activation by serum MBP is discussed with reference to close similarity in the gross structures of serum MBP and C1q.

Animals↗
PubMed1987

Effects of highly purified eicosapentaenoic acid on plasma beta thromboglobulin level and vascular reactivity to angiotensin II.

Eicosapentaenoic acid (EPA), the precursor fatty acid of three series of prostaglandins, has been reported to have an antiatherothrombotic potential. We gave highly purified EPA in a soft capsule (90% ethylester form of EPA; EPA-E) to 6 healthy male volunteers for 4 weeks. After the administration of 900 mg/day of EPA-E for two weeks or longer, a significant reduction in plasma beta thromboglobulin level was observed, and after 4 weeks' administration, significantly blunted pressor responsiveness to infused angiotensin II was observed. These changes were not observed 4 weeks after EPA-E had been discontinued. After 4 weeks' ingestion of EPA-E, the platelet count, mean platelet volume, platelet aggregation with adenosine diphosphate or collagen, plasma recalcification time, prothrombin time, plasma antithrombin III, fibrinogen or plasmin concentrations, serum concentrations of total cholesterol, triglycerides, total phospholipid, nonesterified fatty acid or high-density lipoprotein cholesterol were unchanged. From the data presented it can be said that EPA-E causes a mild depression of vascular contractility and of platelet aggregability in vivo and exerts a beneficial influence on several cardiovascular factors.

Administration, Oral↗
PubMed1986

Vasopressor activity in incubated plasma of normal and hypertensive pregnant women.

The pressor activity generated in incubated plasma of nonpregnant, normal pregnant, and hypertensive pregnant women was measured by means of a sensitive bioassay technique. It was found that the plasma of normal pregnant women generated significantly higher amounts of active pressor principle than the plasma of nonpregnant women. The plasma of hypertensive pregnant women generated significantly lower amounts of active pressor principle than the plasma of normal pregnant women. Plasma obtained from the antecubital vein revealed no difference in pressor activity compared to plasma collected from the uterine vein at the time of cesarean section. These data suggest that active pressor principle is not involved in the pathogenesis of pregnancy-induced hypertension and that the pregnant uterus is not the source of active pressor principle.

Angiotensin II↗
PubMed1986

Fetal heart monitoring and ultrasound in the management of placental abruption.

Three cases of placental abruption with the "pseudosinusoidal" fetal heart rate (FHR) pattern, a periodic late deceleration related to frequent uterine contractions are reported. This 'pseudosinusoidal' pattern is clearly not a true sinusoidal pattern. The fetal monitoring patterns of these patients are presented and discussed along with the use of ultrasound in the management of this condition. All infants were delivered by cesarean section with low Apgar scores at birth, but they soon recovered completely.

Abruptio Placentae↗