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Biomedical subjects

K Kimura

Publications and source records attributed to K Kimura.

At least 19 recordsLinked to original sources
PubMed1979

Hydrogenase activity in the dry state: isotope exchange and reversible oxidoreduction of cytochrome c3.

Hydrogenase (hydrogen:ferricytochrome c3 oxidoreductase, EC 1.12.2.1) catalyzes three types of reactions, i.e., (1) conversion between hydrogen modifications, para-H2 and ortho-H2, (2) exchange reaction between hydrogen isotopes, and (3) reversible oxidoreduction of an electron carrier with H2 and protons. We observed that purified desulfovibrio hydrogenase in the dry state could catalyze not only the conversion and exchange reactions (Yagi, T., Tsuda, M., Mori, Y. and Inokuchi, H. (1969) J. Am. Chem. Soc. 91, 2801) but also the reversible oxidoreduction of the electron carrier, cytochrome c3 with H2. The rate of the conversion was in the range from 0.1 to 0.65 mol H2 converted per mol hydrogenase per s, and the ratio of the conversion rate to the exchange rate was near 5. The rate of oxidoreduction of cytochrome c3 in the dry state was 0.015 mol H2 taken up in the forward reaction and 0.003 mol H2 released in the reverse reaction per mol hydrogenase per s. The process of these reactions could be explained by the observations that the hydrogenase molecule in the dry state has protons which are directly exchangeable with H2 during catalytic process. The reversible oxidoreduction of cytochrome c3 is also explained by inter- and intramolecular electron transfer among cytochrome c3 molecules.

Cytochrome c Group↗
PubMed1979

Differential diagnosis of pancreatic mass lesion with percutaneous fine-needle aspiration biopsy under ultrasonic guidance.

Ultrasonically guided percutaneous fine-needle aspiration biopsy for cytological diagnosis was performed on 28 patients with ultrasonically scanned solid mass lesions of the pancreas in an attempt to make a differential diagnosis between pancreatic cancer and chronic pancreatitis. In 25 of the 28 patients, enough cells were aspirated to enable a cytological diagnosis to be made. In 19 of these 25 patients, malignant cells were obtained, while the aspirates from 6 patients contained only normal pancreatic cells. In 3 of the 28 patients, insufficient numbers of cells were obtained to allow the establishment of a cytological diagnosis. Pancreatic cancers were present in 22 of the 28 patients, and among these a positive diagnosis of cancer was made by aspiration biopsy in 86.4% (19/22). The technique resulted in no false positive diagnoses of cancer among 6 patients with chronic pancreatitis. No complications, such as bleeding, fistula formation, and elevation of the serum amylase, followed the procedure. This new method appears to be extremely useful in the diagnosis of pancreatic mass lesions.

Adult↗
PubMed1979

Application of magnification radiography to the biliary system.

Magnification radiography was applied for the diagnosis of the biliary tract diseases including cancer. Our X-ray unit was consisting of HITACHI DR-155-23 U-6M-55P and 0.1 mm focal-spot tube, FFD 80 cm giving a magnification of x2 with the conditions of 60 kVp, 20 mA, 0.8 sec. Intensifying screens such as Kyokko LH II (for a standard sized subject) or DuPont Q II (for an obese subject) were used in combination with Fuji RX films. We confirmed a high diagnostic value in revealing early lesions of this sytem. The skin dose test indicated that this technique was routinely applicable with safety for clinical use.

Biliary Tract↗
PubMed1979

The surgical management of the unusual forms of biliary atresia.

Of 50 infants undergoing laparotomy for biliary atresia during the last 9 yr at the Kobe Children's Hospital, 9 had variant forms, including (A) a gallbladder with a demonstrable connection with the intrahepatic biliary system, (B) a gallbladder with a connection with the extrahepatic biliary system and duodenum, and (C) a grossly visible subhepatic cyst. Three patients with form A underwent cholecystoduodenostomy. All these patients died of cholangitis and hepatic failure within 2 mo after operation. Two patients with form B were successfully treated by hepatic portocholecystostomy without any episodes of cholangitis. Two of the patients with form C, occurring in 1970, underwent an anastomosis between the subhepatic cyst and the duodenum. There was no bile excretion in these patients. The other two patients were treated subsequently by hepatic portoenterostomy with complete excision of the subhepatic cyst and excellent bile excretion was obtained. Infants with forms A and C should be treated by hepatic portoenterostomy instead of a direct anastomosis between the dilated portion of the extrahepatic biliary system and the alimentary tract. For patients with form B, hepatic portocholecystostomy seems to be the most suitable procedure relative to the prevention of postoperative cholangitis, which is the most serious complications in infants obtaining successful bile excretion.

Bile Ducts↗
PubMed1979

Technical aspects of hepatic portal dissection in biliary atresia.

During the past 8 yr, 37 patients with a noncorrectable type of biliary atresia have undergone hepatic portoenterostomy or portocholecystostomy at the Kobe Children's Hospital. The hepatic portal dissections employed in this series were classified as "supraportal" (9 procedures), "portal" (25 procedures), and "infra-portal" (3 procedures) based on the level at which the fibrous mass at the porta hepatis was transsected as determined by the operative record and the pathologic findings. Successful biliary drainage was achieved in 19 out of 25 patients (76%) with a "portal" type of dissection, while 1 out of 9 with "supra-portal" and none out of 3 with "infra-portal" type dissections were successful in this respect. Of the 19 patients who achieved significant biliary flow, 8 have lived for 2--7 yr without jaundice and 3 others are jaundice-free for shorter intervals.

Bile↗
PubMed1979

Glucose dehydrogenase (hexose 6-phosphate dehydrogenase) and the microsomal electron transport system. Evidence supporting their possible functional relationship.

The ability of a microsomal enzyme, glucose dehydrogenase (hexose 6-phosphate dehydrogenease) to supply NADPH to the microsomal electron transport system, was investigated. Microsomes could perform oxidative demethylation of aminopyrine using microsomal glucose dehydrogenase in situ as an NADPH generator. This demethylation reaction had apparent Km values of 2.61 X 10(-5) M for NADP+, 4.93 X 10(-5) m for glucose 6-phosphate, and 2.14 X 10(-4) m for 2-deoxyglucose 6-phosphate, a synthetic substrate for glucose dehydrogenase. Phenobarbital treatment enhanced this demethylation activity more markedly than glucose dehydrogenase activity itself. Latent activity of glucose dehydrogenase in intact microsomes could be detected by using inhibitors of microsomal electron transport, i.e. carbon monoxide and p-chloromercuribenzoate (PCMB), and under anaerobic conditions. These observations indicate that in microsomes the NADPH generated by glucose dehydrogenase is immediately oxidized by NADPH-cytochrome c reductase, and that glucose dehydrogenase may be functioning to supply NADPH.

Aminopyrine N-Demethylase↗
PubMed1979

Suppression of cell-mediated immunity in rats transplanted with kidneys from donors compatible at the major histocompatibility complex.

In order to study the immunological status of rats transplanted with H-1-compatible kidney allografts, LEW rats were grafted with F and (Fischer X Lewis)F1 (FLEWF1) kidneys. Most of the F kidneys were rejected within 55 days, only 4 of 24 surviving for more than 4 months. However, two-thirds of the FLEWF1 recipients survived for more than 4 months, the others having died within 64 days. During the first postoperative week, high levels of serum lymphocytotoxic antibodies were found in recipients of F kidneys, and thereafter there was little change. In this respect these rats did not differ from recipients of kidneys with major histocompatibility differences. However, recipients of FLEWF1 kidneys had low haemagglutinating and lymphocytotoxic antibody titres. No serum-blocking factor could be found in kidney of recipients by use of the microcytotoxicity assay (MCA) or inhibition of allorosette formation. Cellular immunity, which was studied by means of the graft-versus-host reaction (GVHR) and the microcytotoxicity assay, was detected in the first postoperative week. This immunity gradually declined, and after 6 weeks it was no longer detectable. The immunological status of the long-term surviving kidney recipients remained unchanged, even when they were provided with further antigenic challenge in the form of two successive donor strain skin grafts.

Animals↗
PubMed1979

Effects of pH of the medium on flagellation of Vibrio parahaemolyticus.

Formation of the lateral flagella by Vibrio parahaemolyticus was inhibited under an alkaline condition of the medium. However, flagellation of the polar monotrichous flagellum was not affected in the same condition. Flagellation of the lateral flagella depended on the pH of the medium.

Culture Media↗
PubMed1979

Early metabolic disturbances in the liver following unilateral hepatic or common bile duct obstruction in rabbits.

The early metabolic disturbances in the liver following ligation of the left hepatic or the common duct were studied in the rabbit. In the rabbits subjected to ligation of the left hepatic bile duct, the phosphorylative activity of the liver mitochondria in the ligated lobe decreased to about 50% of controls 48 h after the ligation, while that in the nonligated lobe increased 2-fold. These rabbits continued to live. On the other hand, in the rabbits subjected to ligation of the common bile duct, the mitochondrial phosphorylative activity increased slightly at 3 h after the ligation but fell rapidly thereafter. The mitochondrial free NAD+ to NADH ratios and hepatic energy charge (ATP+1/2ADP/ATP+ADP+AMP) markedly decreased after the ligation. Most of these rabbits did not survive over 2 days. These results indicate that the metabolic disturbances in the jaundiced liver are due to an impairment of the oxidative phosphorylation. In addition, it is suggested that the maintenance of the energy balance by enhanced mitochondrial phosphorylative activity is readily impaired in the jaundiced liver.

Adenine Nucleotides↗
PubMed1979

Measurement of plasma renin concentration using exogenous human renin substrate in normal subjects: correlation with plasma renin concentration and plasma aldosterone concentration.

Measurement of plasma renin concentration (PRC) was done in normal subjects at rest and under acute stimulation of renin release under unrestricted sodium intake. Concurrent measurements of plasma renin activity (PRA) and plasma aldosterone concentration (PA) were carried out. The mean values of PRC at rest and after stimulation of renin release were 12.8 +/- 1.3 (SEM) and 21.7 +/- 4.4 (SEM) ng AT I/ml/h, respectively. These corresponded to renin contents of 3.4 +/- 0.34 (SEM) X 10(-5) Goldblatt units and 5.8 +/- 0.36 (SEM) respectively. The mean percent increase of PRC (82.1 +/- 19.3 (SEM)) %) was almost indentical to that of PA (81.5 +/- 16.4 (SEM) %), but differed from that of PRA (269 +/- 83.1 (SEM) %). A very high correlation between concurrent PRC and PA (r = 0.92, P less than 0.001) was found in normal subjects at rest and under acute stimulation of renin release. A good correlation between PRC and PRA (r = 0.85, P less than 0.001) was also observed. However, a higher correlation between percent increases of PRC and PA (r = 0.92, P less than 0.001) than that of PRA and PA (r = 0.80, 0.01 less than P less than 0.005) was found. Results show that PRA is a good index of the renin content in plasma in normal subjects at rest and PRC reflects actual renin concentration in plasma at rest as well as under stimulation of renin release.

Adult↗
PubMed1979

Effects of intraventricularly administered serotonin, noradrenaline, dopamine and metaraminol on the reserpine-induced spikes recorded from the medial nucleus trapezoides in rabbits.

Effects of intraventricularly administered serotonin (5HT), noradrenaline (NA), dopamine (DA) and metaraminol on the reserpine-induced spikes recorded from the medial nucleus Trapezoides (Trap. m.) in rabbits were investigated. 5HT (30, 50 micrograms) produced marked decreases in the amplitude and discharge rate of the spikes 3 to 5 min after intraventricular administration. NA (30, 50 micrograms) also produced similar effects to those of 5HT, but DA at the same dosage produced no significant changes in the amplitude and discharge rate of spikes. Metaraminol, a metabolite of alpha-methyl-m-tyrosine, produced gradual and long-lasting, potent suppression of spikes. Ninety min later, spikes were completely suppressed, and no recovery was observed within 6 hours after intraventricular administration. These results indicate that NA has a similar suppressing action to that of 5HT on the generation of the reserpine-induced spikes.

Action Potentials↗
PubMed1979

The effect of phenoxybenzamine on the pulmonary vascular bed in surgically corrected ventricular septal defect associated with pulmonary hypertension.

From 1971 to 1977, a total of 43 cases with ventricular septal defect associated with pulmonary hypertension (VSD + PH), ranging from 3 months to 6 years of age, underwent VSD closure using cardiopulmonary bypass with a prophylactic dose of phenoxybenzamine (POB) 1 mg/Kg. Twenty of these cases are included in the present study of the effect of POB on pulmonary hypertension. The ratios of pulmonary to systemic arterial pressures (Pp/Ps) and vascular resistances (Rp/Rs) were measured before, immediately after and 1 month after VSD closure. In all cases, the Pp/Ps before VSD closure was larger than 0.75. Both Pp/Ps and Rp/Rs markedly decreased immediately after VSD closure but rose again 1 month thereafter. These results suggest the possibility of pulmonary vasodilating effect of POB, which could be potentially useful in relieving the right ventricular load in the early postoperative period. The over all mortality was 3 out of 43 cases including 2 late deaths.

Blood Pressure↗