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Biomedical subjects

K Fukuda

Publications and source records attributed to K Fukuda.

At least 721 records · Page 40Linked to original sources
PubMed1989

[A successful treatment of an infective endocarditis caused by methicillin-resistant Staphylococcus aureus with a combination of cefmetazole with fosfomycin].

A case of infective endocarditis caused by methicillin-resistant Staphylococcus aureus (MRSA) was successfully treated with a combination therapy with cefmetazole (CMZ) and fosfomycin (FOM). A 55 year old man was admitted to the Keio Hospital because of fever of unknown origin. Physical examination revealed blood pressure of 132/62 mmHg, heart rate of 118/min and body temperature of 39.8 degrees C. Diastolic regurgitant murmur (Levine II/VI) was heard at the left sternal border on the third intercostal space. Chest X-ray showed mild cardiomegaly. Two dimensional echocardiography and color flow mapping demonstrated mildly dilated and hyperkinetic left ventricle, redundant aortic valve, giant vegetation from the aortic valve and severe aortic regurgitation. MRSA was isolated from the blood of this patient. Bacteriostatic synergism between CMZ and FOM against S. aureus isolated from the blood of this patient was detected both by the Kirby-Bauer method and by the checker-board method. The combination therapy with CMZ and FOM cleared the clinical symptoms and normalized the inflammatory reactions. No relapse was observed for at least 10 months. We concluded that the combination therapy with CMZ and FOM was invaluable for the treatment of infections endocarditis by MRSA.

Cefmetazole↗
PubMed1988

Intracellular calcium release mediated by two muscarinic receptor subtypes.

Four subtypes of muscarinic acetylcholine receptor (mAChR) were stably expressed in neuroblastoma-glioma hybrid cells (NG108-15). By combining fluorescent indicator dye (fura-2) studies with electrophysiological measurements it is shown that stimulation of mAChR I and mAChR III readily leads to release of calcium from intracellular stores and to associated conductance changes, whereas stimulation of mAChR II and mAChR IV exerts no such effect. Dose-response curves describing the amplitude or the delay of the calcium rise induced by acetylcholine suggest that the apparent affinity of mAChR III for its agonist is higher by about one order of magnitude than that of mAChR I. Ionic substitution experiments and current fluctuation analysis indicate that calcium activates a K+-specific conductance of 'small' single-channel amplitude similar to the SK type. Furthermore, an outward current (M current) suppressed by activation of mAChR I and mAChR III has a single-channel amplitude corresponding to a conductance of approximately 3 pS.

Acetylcholine↗
PubMed1988

Different sensitivities to agonist of muscarinic acetylcholine receptor subtypes.

Muscarinic acetylcholine receptor (mAChR) III expressed in Xenopus oocytes, like mAChR I, mediates activation of a Ca2+-dependent Cl- current, whereas mAChR IV, like mAChR II, principally induces activation of Na+ and K+ currents in a Ca2+-independent manner. mAChR III has a sensitivity to agonist of about one order of magnitude higher than that of mAChR I in mediating the Ca2+-dependent current response in Xenopus oocytes and in stimulating phosphoinositide hydrolysis in NG108-15 neuroblastoma-glioma hybrid cells. The agonist-binding affinity of mAChR III is also about one order of magnitude higher than that of mAChR I.

Acetylcholine↗
PubMed1988

Rings of negatively charged amino acids determine the acetylcholine receptor channel conductance.

The structure-function relationship of the nicotinic acetylcholine receptor (AChR) has been effectively studied by the combination of complementary DNA manipulation and single-channel current analysis. Previous work with chimaeras between the Torpedo californica and bovine AChR delta-subunits has shown that the region comprising the hydrophobic segment M2 and its vicinity contains an important determinant of the rate of ion transport through the AChR channel. It has also been suggested that this region is responsible for the reduction in channel conductance caused by divalent cations and that segment M2 contributes to the binding site of noncompetitive antagonists. To identify those amino acid residues that interact with permeating ions, we have introduced various point mutations into the Torpedo AChR subunit cDNAs to alter the net charge of the charged or glutamine residues around the proposed transmembrane segments. The single-channel conductance properties of these AChR mutants expressed in Xenopus laevis oocytes indicate that three clusters of negatively charged and glutamine residues neighbouring segment M2 of the alpha-, beta-, gamma- and delta-subunits, probably forming three anionic rings, are major determinants of the rate of ion transport.

Amino Acid Sequence↗
PubMed1988

Selective coupling with K+ currents of muscarinic acetylcholine receptor subtypes in NG108-15 cells.

The primary structures of two muscarinic acetylcholine receptor (mAChR) species, designated as mAChR I and mAChR II, have been elucidated by cloning and sequence analysis of DNAs complementary to the porcine cerebral and cardiac messenger RNAs, respectively. mAChR I and mAChR II expressed in Xenopus oocytes differ from each other both in acetylcholine-induced response and in antagonist binding properties. These results, together with the differential tissue location of the two mAChR mRNAs, have indicated that pharmacologically distinguishable subtypes of the mAChR represent distinct gene products. The primary structures of two additional mammalian mAChR species, designated as mAChR III and mAChR IV, have subsequently been deduced from the nucleotide sequences of the cloned cDNAs or genomic DNAs. We report here that mAChR I and mAChR III expressed in NG108-15 neuroblastoma-glioma hybrid cells, but not mAChR II and mAChR IV, efficiently mediate phosphoinositide hydrolysis, activation of a Ca2+-dependent K+ current and inhibition of the M-current, a voltage-dependent K+ current sensitive to muscarinic agonists.

Acetylcholine↗
PubMed1988

Site-directed mutagenesis of the cAMP-binding sites of the recombinant type I regulatory subunit of cAMP-dependent protein kinase.

The type I regulatory subunit (R-I) of rat brain cAMP-dependent protein kinase was expressed in E. coli and site-directed mutagenesis was used to substitute amino acids in the putative cAMP-binding sites. The wild-type recombinant R-I bound 2 mol of cAMP/mol subunit, while two mutant R-Is with a single amino acid substitution in one of the two intrachain cAMP-binding sites (clone N153:a glutamate for Gly-200, and clone C254:an aspartate for Gly-324) bound 1 mol of cAMP/mol subunit. When these two substitutions were made in one mutant, cAMP did not bind to this mutant, indicating that binding of cAMP to N153 or C254 was to their nonmutated sites. Competition experiments with site-selective analogs and dissociation of bound cAMP from mutant R-Is provided evidence for strong intrachain interactions between the two classes of cAMP-binding sites in R-I.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1988

Type V collagen selectively inhibits human endothelial cell proliferation.

Type V collagen from human placenta remarkably inhibited human umbilical vein endothelial cell (HUVEC) proliferation in a dose-dependent manner when coated on the culture dishes. Other types of collagen (I, III, IV) and fibronectin enhanced HUVEC proliferation under the same conditions. The inhibitory activity of type V collagen was seen not only when it was coated on the dishes, but also when it was directly added into cell culture. The attachment effect of type V collagen did not differ from that of type I collagen. The inhibitory activity is a phenomenon selective for endothelial cells, since type V collagen did not affect the proliferation of human umbilical vein smooth muscle cells, aortic smooth muscle cells, or nasal mucosa fibroblasts.

Cell Adhesion↗
PubMed1988

A case-control study of past history of nasal diseases and maxillary sinus cancer in Hokkaido, Japan.

A case-control study of maxillary sinus cancer was performed in Hokkaido with 116 cases and 232 controls matched for sex, age (within 5 years), and residence (same health center region). Preliminary univariate analyses showed that a history of chronic sinusitis [relative risk (RR) = 3.1]; nasal polyps (RR = 5.7); an occupational history of being a carpenter, joiner, furniture maker, or other woodworker (RR = 2.9); and a history of current or past cigarette smoking (RR = 3.3) were statistically significant risk factors for men. No single item was a significant risk factor for women.

Adult↗
PubMed1988

Examination of previous caesarean section scars by ultrasound.

We examined 84 lower segment caesarean section scars by ultrasonography near term. Seventy scars showed good healing with a thickness of the lower uterine segment of more than 3 mm; 14 scars showed poor healing with a thickness of less than 2 mm and loss of continuity. Among 70 patients with good healing, 24 patients delivered vaginally but the remaining 46 patients have had repeat caesarean sections for other obstetric indications. Intraoperative findings in these 46 patients were as follows: Grade I (no thinning of the lower uterine segment), 42; Grade II (thinning and loss of continuity of the lower uterine segment but fetal hair not visible), 4; Grade III (thinning of the lower uterine segment and fetal hair visible), 0. Fourteen patients with poor healing had repeat caesarean sections. Intraoperative findings in these 14 patients were as follows: Grade I, 0; Grade II, 9; Grade III, 5. These results indicate that ultrasound examination detect thinning of the lower uterine segment and may help to determine management.

Adult↗
PubMed1988

Stopped-flow investigation of antioxidant activity of tocopherols. Finding of new tocopherol derivatives having higher antioxidant activity than alpha-tocopherol.

Second-order rate constants, kappa s, for H-atom abstraction by phenoxyl radicals from five tocopherol (vitamin E) derivatives have been measured spectrophotometrically at 25.0 degrees C by the stopped-flow method, as a model reaction of tocopherols with unstable free radicals (LOO., LO., and HO.) in biological systems. Three new tocopherol derivatives with a five-membered heterocyclic ring were found to be 1.9-2.1 times more active than the alpha-tocopherol which has the highest antioxidant activity among natural tocopherols. The proton hyperfine splittings for the five tocopheroxyl radicals derived from these tocopherols by the reaction with phenoxyl were also determined by ESR measurements.

Antioxidants↗
PubMed1988

Cardiovascular effects of intravenous and intracoronary administration of atrial natriuretic peptide in halothane anesthetized dogs.

Cardiovascular actions of synthetic 1-28 human natriuretic peptides (hANP) were examined in dogs anesthetized with halothane. In seven closed-chest dogs a Swan-Ganz catheter was inserted for measurement of cardiac output. Intravenous infusion of increasing doses of hANP (0.1, 0.3, 0.9 microgram/kg/min) lowered mean aortic pressure without affecting heart rate significantly. Cardiac output and pulmonary wedge pressure were markedly decreased while total peripheral resistance was increased significantly. All these parameters returned to control levels after 1 hr of recovery with an 100-150ml of saline infusion to increase pulmonary capillary wedge pressure to the preinfusion value. Intracoronary infusion of hANP (0.05 and 0.1 microgram/kg/min) did not cause any significant changes in coronary flow and regional contraction. These results indicate that the hypotensive action of hANP is due to a decrease in cardiac output mediated by reduced preload but not by negative inotropic action.

Anesthesia↗
PubMed1988

Long-standing bidirectional tachycardia in a patient with hypokalemic periodic paralysis.

Bidirectional tachycardia is an uncommon arrhythmia that usually occurs in aged persons with severe myocardial disease or digitalis intoxication, and carries a poor prognosis. This is a report of a young woman with familial hypokalemic periodic paralysis, who has a 13-year history of asymptomatic bidirectional tachycardia in the absence of organic heart disease or digitalis intoxication. Association of periodic paralysis and bidirectional tachycardia in this case and four previously reported cases suggests a strong relationship between this arrhythmia and potassium.

Adult↗
PubMed1988

Increased concentration of calcium channel and intracellular free calcium in the acute phase of deoxycorticosterone acetate salt hypertension.

Cardiac calcium channels and platelet Ca2+ concentrations were examined in deoxycorticosterone acetate (DOCA)-salt hypertension in rats to clarify the role of calcium channels in the regulation of intracellular Ca2+. Calcium channels were determined by the radioligand binding method and platelet Ca2+ concentrations were measured by a fluorescent Ca2+ indicator, Quin-2. The number of cardiac calcium channels was increased in DOCA-salt hypertension compared with controls 10 days after nephrectomy. Platelet Ca2+ concentrations were also increased in the acute phase of DOCA-salt hypertension. No significant changes were observed in the number of cardiac calcium channels and in platelet Ca2+ concentrations in the chronic phase of DOCA-salt hypertension. These results suggest that the increased platelet Ca2+ concentrations are induced by the increase in the number of calcium channels in the acute phase of hypertension.

5'-Nucleotidase↗
PubMed1988

Heterotransplantation of an alpha-fetoprotein-producing human gallbladder carcinoma into nude mice.

An alpha-fetoprotein (AFP)-producing human gallbladder carcinoma showing direct invasion into the liver was transplanted into BALB/c-nu/nu nude mice. Although patient serum levels of AFP and carcinoembryonic antigen (CEA) were within normal limits, they were elevated to 1,040 ng/ml and 22.1 ng/ml, respectively, after cholecystectomy. Prominent liver metastasis was demonstrated by diagnostic imaging techniques shortly after the operation. Pathologically, the resected tumor consisted of papillotubular adenocarcinoma and the part which had invaded the liver showed a solid growth pattern with no papillo-tubular structure. The transplanted tumor showed both papillo-tubular and solid growth patterns, in which positive reactions for AFP, CEA, ferritin (FER), carbohydrate antigen 19-9 (CA 19-9), albumin (ALB) and fibrinogen (FIB) were confirmed by the avidin-biotin-peroxidase complex method. Serum levels of AFP, CEA, CA 19-9, beta 2-microglobulin (BMG) and FER were elevated in the nude mice bearing tumor transplants. Twenty-five percent of the serum AFP from nude mice with tumor transplants bound with concanavalin A (Con A), suggesting that the tumor was of gastrointestinal rather than hepatic origin.

Adenocarcinoma↗
PubMed1988

Malacoplakia of the endometrium. An unusual case studied by electron microscopy and a review of the literature.

A rare case of malacoplakia (MKP) of the endometrium in an 88-year-old Japanese woman is presented. By light microscopy, typical Michaelis-Gutmann bodies (M-G bodies) could be identified. Electron microscopic findings revealed M-G bodies in various stages of development. These features suggested that M-G bodies were derived from round electron-dense granules that coalesced to form phagolysosomes. Early-stage M-G bodies were manifested as small, irregular, needle-shaped areas of calcification in phagolysosomes. The present paper reviews 6 cases of endometrial MKP, 5 of which have previously been reported in the literature, and this case being the sixth, to our knowledge.

Adult↗