Biomedical subjects

K Minakuchi

Publications and source records attributed to K Minakuchi.

At least 19 recordsLinked to original sources

PubMed1996

Sensitive quantitation of nitric oxide by EPR spectroscopy.

A recent method for NO detection is electron paramagnetic resonance (EPR) with ferrous and mononitrosyl dithiocarbamate (Fe2+ (DETC)2) for spin trapping [Menon, N.K., et al., J.Mol. Cell Cardiol., 23:389; 1991]. However, by this technique, we failed to detect the spectrum of the NOFe2+ (DETC)2 complex in biological systems because of the low solubility of Fe2+ (DETC)2 and rapid oxidation of NOFe2+ (DETC)2 complex. To overcome these problems, we modified this method by adding albumin to solubilize Fe2+ (DETC)2 and Na2S2O4 as a strong reductant to increase the sensitivity and stability of the EPR spectrum of the NOFe2+ (DETC)2 complex. The optimal concentrations of these reagents were 3.3 mM of Fe2+ and DETC, 33 mg/ml albumin and 2 M Na2S2O4. The detection limit was less than 10 pmol/ml under these conditions. By this modified method, we succeeded in quantifying NO production from porcine aorta induced by forskolin.

Animals↗

PubMed1995

Calcium efflux from cultured bovine adrenal chromaffin cells induced by pituitary adenylate cyclase-activating polypeptide (PACAP): possible involvement of an Na+/Ca2+ exchange mechanism.

The effect of pituitary adenylate cyclase-activating polypeptide 1-38 (PACAP1-38) on Ca2+ efflux from cultured bovine adrenal chromaffin cells was examined. PACAP1-38 stimulated the efflux of 45Ca2+ from the cells in a concentration dependent manner (10(-9)-10(-7)M). This effect was inhibited by its potent receptor antagonist PACAP6-38. PACAP1-38 increased the formation of [3H]inositol phosphates and cyclic AMP in the cells. Forskolin, an activator of adenylate cyclase, also stimulated the efflux of 45Ca2+ from the cells. 3-Isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterase, enhanced PACAP1-38-induced 45Ca2+ efflux from the cells. Phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C, had no effect on the efflux of 45Ca2+ from the cells. The increases in 45Ca2+ efflux induced by PACAP1-38 and forskolin were reduced by deprivation of extracellular Na+ and the Na+/Ca2+ exchange inhibitor amiloride. In addition, PACAP1-38 stimulated 22Na+ influx into the cells, and this action was inhibited by amiloride. These results suggest that PACAP1-38 stimulates an Na+/Ca2+ exchange mechanism through activation of adenylate cyclase in cultured bovine adrenal chromaffin cells.

1-Methyl-3-isobutylxanthine↗

PubMed1995

Potentiation by ouabain of bradykinin-induced catecholamine secretion and calcium influx into cultured bovine adrenal chromaffin cells: evidence for involvement of Na+ influx associated with the bradykinin B2-receptor.

The effect of bradykinin (BK), in the presence of ouabain, an inhibitor of Na(+)-K+ ATPase, on catecholamine (CA) secretion was studied in cultured bovine adrenal chromaffin cells, to determine whether Na+, as well as Ca2+, is involved in BK-receptor mediated CA secretion. BK (10(-8)-10(-5) M)-induced CA secretion was markedly potentiated by addition of ouabain (10(-5) M), was blocked by a BK-B2 receptor antagonist, and was decreased in Ca(2+)-free medium. BK-induced increase in 45Ca2+ influx was also potentiated by addition of ouabain. The cultured cells were first incubated with BK for 30 min in Ca(2+)-free medium in the presence or absence of ouabain and then stimulated for 15 min with Ca(2+)-medium without BK or ouabain. Prior stimulation of the cells, BK induced 22Na+ influx and increased Ca(2+)-induced CA secretion and these stimulatory effects of BK were potentiated by added ouabain. When the cells were stimulated with BK and ouabain in Na(+)-free sucrose medium, the Ca(2+)-induced CA secretion was greatly reduced. These results indicated that activation of the BK-B2 receptor and inhibition of the Na+ pump both increase the intracellular Na+ level, resulting in increase in Ca2+ influx and CA secretion.

Animals↗

PubMed1995

Maintaining low concentrations of plasma beta 2-microglobulin through continuous slow haemofiltration.

As a first step in the development of a future wearable artificial kidney, we conducted three forms of treatment with continuous haemofiltration (CHF) on a group of 10 patients in an attempt to determine what plasma values of small molecules and beta 2-microglobulin (beta 2-M) could be maintained. In the first system, one ordinary 4-h haemodialysis, followed by 7-day CHF with 51 exchange per day, was repeated. The second system consisted of CHF with 51 exchange/day and thrice weekly slow nocturnal dialysis. The third system used CHF with 101 exchange per day. The first, second and third systems were used with three, four and four patients, respectively, for at least 4 weeks each. PAN-DX and FH-66 haemofilters were used eight and three times, respectively, with continuous infusion of heparin at 500-700 units/h. In the first system, the pre-CHF plasma beta 2-M was 45.5 +/- 3.1 mg/l, against a much lower 18.8 +/- 1.0 mg/l 4 weeks later. With the second system, this decrease was from 43.5 +/- 5.7 mg/l to 18.1 +/- 1.1 mg/l with 4 weeks treatment, and from 44.7 +/- 3.4 mg/l to 18.1 +/- 1.4 mg/l with 3 weeks treatment. Pre-haemodialysis treatment levels of urea nitrogen, plasma creatinine and uric acid in the first system were greater than ordinary pre-haemodialysis levels. On the second system, these were kept at -54 +/- 8.3%, -52.2 +/- 6.7% and -47.6 +/- 4.4% of the ordinary pre-haemodialysis levels, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1995

[Studies on attenuation of post-ischemic brain injury by kampo medicines-inhibitory effects of free radical production. II].

It is thought that highly reactive oxygen radicals generated at the ischemia-reperfusion in case of strokes play an important role in damaging the brain. It is well known that lipid peroxidation is propagated by active oxygen radicals, and the the brain is susceptible to the lipid peroxidation. In the previous study, we found that several Chinese herbal medicines and kampo components, which were used for the attenuation of the post-ischemic brain injury, showed a free-radical (OH., O2-. and DPPH) scavenging activity. However, it is not clear whether these Chinese herbal medicines can inhibit the lipid peroxidation reaction or not. In attempting to address this question, we have used three kinds of kampo formulations (Oren-gedoku-to (Huang-Lian-Jie-Du-Tang), Saiko-ka-ryukotsu-borei-to (Chai-Hu-Jia-Long-Gu-Mu-Li-Tang) and Keishi-bukuryo-gan (Gui-Zhi-Fu-Ling-Wan)) to measure the suppressive effect of the lipid peroxidation on the mouse cerebrum using the TBA technique in vitro and in vivo. In vitro experiments, all these Chinese herbal medicines decreased the levels of TBA-reactive substances concentration-dependently. In vivo studies, the levels of the TBA-reactive substance of the cerebrum homogenate of mice treated with these kampo formulations by p.o. for three weeks also decreased. From these results, we suggest that the pharmacological action of Chinese herbal medicines used for the attenuation of the post-ischemic brain damage not only have a free-radical scavenging activity, but also have a suppressive effect on the generation of the lipid peroxidation.

Animals↗

PubMed1994

[MR pyelography using fast spin echo technique in hydronephrosis].

MR pyelography using the fast spin echo technique and and a body coil were performed in ten patients with hydronephrosis. In all cases, pyelograms of the dilated urinary tract were obtained by this method, although they were obtained in only two cases by drip infusion pyelography. MR pyelography is an effective method with which to obtain images of dilated urinary tract non-invasively, and in a relatively short time. This method was also useful to evaluate intraureteral structure.

Adolescent↗

PubMed1994

Mechanism of histamine-induced calcium efflux from cultured bovine adrenal chromaffin cells: possible involvement of an Na+/Ca2+ exchange mechanism.

The effect of stimulation of the histamine receptor on Ca2+ mobilization in cultured bovine adrenal chromaffin cells was examined. Histamine (10(-5) M) increased the intracellular free Ca2+ ([Ca2+]i) to a peak in the presence or absence of extracellular Ca2+, followed by decrease with time. Histamine (10(-8)-10(-5) M) also stimulated 45Ca2+ efflux from cultured bovine adrenal chromaffin cells in a concentration dependent manner. Its stimulatory effect on 45Ca2+ efflux was inhibited by the specific histamine H1 receptor antagonist mepyramine. The increase in histamine-stimulated 45Ca2+ efflux was inhibited by deprivation of extracellular Na+ and by the Na+/Ca2+ exchange inhibitor amiloride. In addition, histamine stimulated 22Na+ influx into the cells, and this action was inhibited by amiloride. These results suggest that stimulation of the histamine H1 receptor regulates Na+/Ca2+ exchange in cultured bovine adrenal chromaffin cells.

Adrenal Medulla↗

PubMed1994

[Arterial infusion chemotherapy with human tumor necrosis factor (TNF): an experimental study using rabbits bearing VX2 tumor].

To evaluate the direct effects of TNF on tumor vessels, three groups of Japanese white rabbits bearing VX2 tumor received 5000 U, 25000, U, and 5000 U of TNF respectively. Angiograms were obtained before, and at 1, 15 and 30 minutes after arterial TNF injection. At 1 minute after TNF injection, dilated tumor vessels and dense tumor stains, depending on the dose of TNF, were demonstrated. At 30 minutes after injection these findings had disappeared However, there were no changes in normal vessels. It is suggested that arterial TNF injection influenced tumor vessels without damaging on normal vessels, indicating that it is effective as cancer therapy.

Animals↗

PubMed1994

[Embolization of varicocele with ethanol].

Embolization with ethanol was performed in 40 varicocele patients to prevent recurrence due to collateral formation. A prescribed amount of ethanol (0.5-4 ml) was injected slowly into the testicular vein with the catheter tip as close as possible to the inguinal region. Embolization with stainless steel coils was also performed in 15 of the 40 patients. Immediately after embolization, three varicoceles were reduced in size, and 37 disappeared. Recurrence was recognized in only two patients. These patients were embolized at a proximal site above lumbar vertebra IV. Spermatic data have improved for 13 patients but not for one azoospermatic patient. Serious complications were recognized in only one patient, who received an injection of 15 ml ethanol in one dose. Therefore, we conclude that embolization with ethanol is an useful treatment for varicocele.

Adolescent↗

PubMed1994

Cloning and sequence analysis of a cDNA encoding rice glutaredoxin.

A full-length cDNA clone (RASC8) encoding glutaredoxin (thioltransferase) was isolated from a cDNA library of an aleurone layer prepared from a developing seed of rice (Oryza sativa L.). RASC8, 568bp in length, contained an ATG codon and two possible polyadenylation signals, and encoded 112 amino acid residues. Cys-Pro-Phe-Cys, which is the active site and a highly conserved sequence among thioltransferases, was found in the deduced amino acid sequence. RASC8 was introduced into an expression vector pMALc2 and the translated product possessed thioltransferase activity.

Amino Acid Sequence↗

PubMed1994

[Studies on attenuation of post-ischemic brain injury by kampo medicines-inhibitory effects of free radical production. I].

In view of the recent investigation, highly reactive oxygen-derived free radicals may play a role in cerebral ischemia and brain damage, free radical scavenging activity of kampo formulations (Oren-gedoku-to, Keishi-bukuryogan, Saiko-ka-ryukostu-borei-to and Daio-botampi-to) and Kampo components (Ityou, Shini, Menamomi, Arinosudama and Denshiti), used for the attenuation of brain damage, was investigated in vitro. The used experimental system was a radical scavenging action against 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide anion radical (O2-.) and hydroxyl radical (OH.) by the electron spin resonance technique at room temperature. All kampo formulations and kampo components showed radical scavenging activity in a concentration-dependent manner. This result indicates that kampo formulations, treated for brain damage, were good radical scavenger that could possibly prevent ischemic complications such as formation of brain damage. The intensity of scavening activity of kampo formulations for three types of radicals were as follows; 1. DPPH: Daio-botampi-to > Saiko-ka-ryukotsu-borei-to = Keishi-bukuryo-gan > Oren-gedokuto, 2. O2-.: Daio-botampi-to = Keishi-bukuryo-gan > Saiko-ka-ryukotsu-borei-to > Oren-gedoku-to, 3. OH.: Daio-botampi-to = Saiko-ka-ryukotsu-borei-to > Keishi-bukuryo-gan = Oren-gedoku-to. Daio-botampi-to indicated the strongest scavenging activity against three types of radicals. Ischemic brain damage is thought to be an "oketsu" syndrome, which is correlated with abnormalities of the microcirculation. Therefore, Daio-botampi-to, which has been used for "oketsu" syndrome, showed superior free-radical scavenging activity.

Brain Ischemia↗

PubMed1993

Efficacy of digital subtraction angiography for confirmation of position of the infusion tube for delivery of intra-arterial chemotherapy as treatment of the head and neck cancer.

This study was conducted in 47 patients with biopsy-proven cancer of the head or neck. These patients each had an intra-arterial infusion tube inserted retrogradely. Positioning in the infusion tubes had been determined by staining of the mucocutaneous area of the malignant lesion under observation with injection of blue dye. Digital subtraction angiography (DSA) was performed from the infusion tube. DSA demonstrated that infusion tubes were in the correct position in 26 patients (55%), and in an incorrect position in 21 patients (45%). The infusion tubes of all patients with cancer of the maxillary sinus were in the correct position. However, the majority (54%) of infusion tubes in patients with cancer of the tongue were in an incorrect position. Observation of arterial flow from the infusion tube using DSA should be made in all patients with head or neck cancer in order to avoid the potential complications of intra-arterial chemotherapy.

Adult↗

PubMed1993

Intravenous digital subtraction angiography of the internal jugular veins.

92 patients with various head-related symptoms were underwent study with IV-DSA. The width and density of the internal jugular veins were compared with the width and density of the common carotid arteries. The right internal jugular vein was more than twice as broad as the common carotid artery in 58 patients (63%), and was denser than the common carotid artery in 14 patients (15%). On the other hand, the left internal jugular vein was broader than the common carotid artery in 76 patients (83%) and more than twice as broad as the common carotid artery in 19 patients (21%). However, the left jugular vein was narrower than the common carotid artery in 12 patients (13%), and in 5 patients (5%) could not be demonstrated. If it is recalled that the internal jugular veins are sometimes congenitally aplastic or hypoplastic as developmental variations of the confluence of sinuses, the occurrence of complications associated with retrograde catheterization can be minimized.

Adolescent↗

PubMed1993

The antiseptic effect of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution.

A quick drying rubbing type disinfectant of non-water non-towel type is an antiseptic method suitable for practical use in intensive care units where emergency situations are common. We determined the antiseptic efficacy and safety of a quick drying rubbing type povidone-iodine alcoholic disinfectant solution (HAD Hand Wash) in comparison with benzalkonium chloride alcoholic lotion. The bacterial reduction rate obtained by hand washing with a single 3 ml application was 93.8% for HAD Hand Wash and 94.1% for benzalkonium chloride alcoholic lotion. Thus, excellent antiseptic efficacy was obtained with both disinfectants. Roughening of hand skin which appeared in association with HAD Hand Wash solution was transient and mild in nature in all of the cases, indicating the high safety of this disinfectant. It is justified to say from these findings that HAD Hand Wash is useful as a hand and finger disinfectant.

Antisepsis↗

PubMed1992

Clinical evaluation of intermittent arterial infusion chemotherapy with an implanted reservoir for hepatocellular carcinoma.

A total of 45 patients with advanced hepatocellular carcinoma were treated at Osaka City University Hospital by intermittent arterial infusion chemotherapy with an implanted reservoir. The treatment consisted of intermittent infusion of doxorubicin (5-20 mg/body), mitomycin C (4-10 mg/body) or degradable starch microspheres (600-1200 mg/body) plus doxorubicin (30 mg/body). In all, 26% of the patients received this treatment for disease recurrence following transcatheter arterial embolization (TAE). Among 43 evaluable patients, 4 showed a complete remission (CR) and 16 showed a partial response (PR) on computed tomograms and angiograms. For all 45 patients, the 1-year survival value was 41% and the 2-year value was 14%. Of the 20 patients who showed a CR or PR, 77% survived for 1 year and 29% survived for 2 years. Tumor regression showed a close relationship with the duration of survival. Intermittent arterial infusion with an implanted reservoir caused the least adverse reactions and seems to be appropriate for use in patients with advanced tumor extension or stenosis of the hepatic artery caused by repeated TAE.

Adult↗

PubMed1992

Changes in plasma free and sulfoconjugated catecholamines before and after acute physical exercise: experimental and clinical studies.

To elucidate whether sulfoconjugated catecholamines in plasma, especially dopamine, serve as a source of free catecholamines, we examined the change in afterload on the deconjugating activity of catecholamines in isolated Langendorff perfused rat hearts. Dopamine-sulfate was administered under ordinary or high-work-load conditions. Free dopamine in the effluent was increased by the high-work-load of the hearts, whereas conjugated dopamine showed an apparent decrease. These results indicate the possibility that deconjugation of sulfoconjugated catecholamines is accelerated by a high-work-load. To obtain further evidence in humans, we also examined the changes in the plasma levels of free and sulfoconjugated catecholamines in healthy volunteers before and after marathon running. Free dopamine increased 1.99-fold from the baseline value after exercise, whereas conjugated dopamine decreased by 12%. Similarly, the plasma levels of free noradrenaline and adrenaline increased after exercise to 2.45- and 1.51-fold their respective baseline values, while conjugated noradrenaline and adrenaline both decreased. These clinical results, as well as those of the experimental studies, suggest that the increase in plasma free catecholamines after exercise is due not only to increased release from the sympathoadrenal system but also to accelerated conversion from sulfoconjugated catecholamines in the plasma.

Adolescent↗

PubMed1992

Clinical evaluation of interventional radiology for renal cell carcinoma in 100 patients.

One hundred of 160 patients with renal cell carcinoma (RCC) were treated by interventional radiology (IVR) in the period from 1978 to 1989. The number and kind of interventions done each year were classified retrospectively. More than half of the patients underwent therapeutic arterial embolization or intraarterial infusion of anticancer drugs during the first half of the period. More recently, about half of the patients have had nephrectomies without IVR. One patient with advanced RCC by IVR 18 times lived 8 years and three months after diagnosis, but that was exceptionally long. IVR has been more effective against hepatocellular carcinoma than RCC, for several reasons.

Angiography↗

PubMed1992

[An assessment of nosocomial infections of methicillin-resistant Staphylococcus aureus based on coagulase typing and phage typing].

An epidemiologic investigation was carried out in Ogaki Municipal Hospital to clarify the status of nosocomial MRSA Infection between 1989 and 1991. In 1989, coagulase type IV, enterotoxin A-producing, and phage group I strains, which were highly resistant to multiple antibiotics and isolated in the internal wards, accounted for 43.4% of all MRSA strains clinically isolated in the entire hospital. In 1990, coagulase type II strains that were sensitive to GM but resistant to FMOX and IPM increased. There were significant differences in the frequency of detection of various strains among wards, suggesting an inter-ward variation in MRSA strains. Changes in environmental strains reflected those in clinical strains. The findings suggest the necessity of measures not only for long-hospitalized MRSA carriers themselves but also for the environment of patients, medical staff, and those taking care of patients.

Bacteriophage Typing↗