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Biomedical subjects

T Kumazawa

Publications and source records attributed to T Kumazawa.

At least 271 records · Page 15Linked to original sources
PubMed1991

Anaesthetic management of dilated cardiomyopathy with severe ventricular dysrhythmias.

A 67-year-old man with dilated cardiomyopathy underwent subtotal gastrectomy. The risks due to anaesthesia and surgery were considered to be very high because of the severe dysrhythmias and renal dysfunction. Anaesthesia was induced with fentanyl and midazolam and maintained with additional fentanyl, midazolam, and 60% nitrous oxide. Dobutamine, dopamine, lignocaine and a temporary pacemaker were used to control cardiovascular responses during surgery. Mild hypotension and tachycardia occurred, but neither circulatory failure nor other major complications were observed during and after the operation.

Aged↗
PubMed1991

[Interaction between diltiazem and sevoflurane in the canine blood-perfused papillary muscle and sinoatrial node preparations].

Experiments were carried out on 17 canine isolated cardiac tissue preparations perfused by arterial blood from donor dogs. Diltiazem was continuously infused i.v. into the conscious (10 dogs) and the sevoflurane anesthetized (2.36%, 7 dogs) donor dogs at a rate of 20 micrograms.kg-1.min-1 for 60 minutes. The changes induced by diltiazem were normalized by the values at the start of diltiazem infusion, and the comparison was made between the two groups. 1) The decrease in heart rate and increase in PQ interval were smaller in conscious dogs than in the anesthetized dogs. 2) Decrease in developed tension in conscious state was smaller than that during sevoflurane anesthesia. 3) There was no significant difference in the decrease in blood pressure or sinoatrial rate between the conscious group and the anesthetized group. These results indicate that sevoflurane anesthesia removes the compensatory reflex which is present in the conscious state and also increases cardiovascular depressant effects of diltiazem.

Anesthetics↗
PubMed1990

Immunolocalization of tyrosine hydroxylase and vasoactive intestinal polypeptide in nerve fibers innervating human palatine tonsil and paratonsillar glands.

The presence of tyrosine hydroxylase (TH) and vasoactive intestinal polypeptide (VIP) in the nerve fibers of the human palatine tonsil and paratonsillar secretory glands is reported. By immunohistochemistry TH-immunoreactive nerves and those immunoreactive to VIP were localized to the tonsil, in particular, the tonsillar vessel wall, extranodular lymphoid tissue and lymph nodule, and to the acinar basal surface of the paratonsillar glands. In the lymph nodule, immunoreactive varicose nerve profiles were observed inside the marginal zone. The germinal center was devoid of immunoreactive fibers.

Adolescent↗
PubMed1990

Electron microscopic observation of calcitonin gene-related peptide-like immunoreactivity in the organ of Corti of the rat.

Calcitonin gene-related peptide (CGRP)-like immunoreactive (CGRP-IR) nerve terminals in the organ of Corti of rats were studied by light and electron microscopy. Surface preparation of the organ of Corti were immunostained using anti-CGRP antiserum for avidin-biotin immunohistochemistry. Dense CGRP-IR fiber bundles were observed by light microscopy in the inner spiral bundles, tunnel spiral bundles and outer spiral bundles. Electron microscopic analysis indicated that CGRP-IR fibers belong to efferent nerves. In the inner spiral bundles, the CGRP-IR fibers showed a direct contact mainly with non-immunoreactive afferent fibers. Some CGRP-IR nerve endings in the inner spiral bundles formed contacts directly with inner hair cells. In the outer spiral bundles, CGRP-IR fibers formed synaptic contacts exclusively with the outer hair cells. It should be noted that the number of synapses of CGRP nerve endings with outer hair cells varied depending upon the sub-row: a falling gradient in number occurred along the inner-outer axis. Our results suggest that CGRP acts as an efferent neuromodulator in the organ of Corti.

Animals↗
PubMed1990

Determination of diquat in biological materials by electron spin resonance spectroscopy.

An electron spin resonance (ESR) method already in use for the quantitative analysis of paraquat was applied to the analysis of diquat in blood, serum, urine, tissue homogenates and several drinks without purification of the samples. The diquat radical produced with ascorbic acid at alkaline pH was much more stable than that produced with the commonly used sodium dithionite. Radical decay in solutions covered with n-hexane was less than 5% after 60 min over a wide range of ascorbic acid concentrations. In 0.2 N NaOH solution 85% of the radicals was present even after 24 h. The limit of detection was 0.3 micrograms/ml and the required amount of sample was 0.1 ml. When both diquat and paraquat were present in a sample the diquat was first extracted with 1-butanol prior to the ESR measurement, because both species were converted to the radicals.

Diquat↗
PubMed1990

The effects of ulinastatin on cardiac and hepatic energy metabolism in rats subjected to hypovolemic shock.

Ulinastatin is a trypsin inhibitor extracted from human urine. In this study the effects of ulinastatin on myocardial and hepatic tissue concentrations of creatine phosphate (CP), ATP, ADP, AMP, lactate, pyruvate, and glycogen have been investigated in rats which were in hemorrhagic shock state. Hypovolemia was induced by bleeding from the femoral artery, and systolic blood pressure was maintained 40 mmHg for 25 min, then ulinastatin 50,000 units.kg(-1) in saline or saline vehicle was intravenously administered. Thereafter the heart and liver were extirpated and frozen quickly with liquid nitrogen. The tissue concentrations of CP, ATP, ADP, AMP, lactate and glycogen were measured enzymatically. Systolic blood pressure elevated significantly after ulinastatin administration. The myocardial tissue CP level was higher in ulinastatin-treated group than that of control group, whereas no significant difference in energy charge between two groups. The hepatic tissue level of AMP, lactate and L/P ratio was lower in ulinastatin-treated group than that of control group, however, no significant difference was found in hepatic tissue level of ATP, ADP and energy charge. From these results it is concluded that ulinastatin can improve the energy metabolism of myocardium to some extent, but not of the liver in rats with hypovolemic shock.

Journal Article↗
PubMed1990

A radioisotopic assay for polyamine oxidase.

A new radioisotopic assay for polyamine oxidase with N1-acetylspermine as substrate is presented. A modified method for the chemical synthesis of radioactive N1-acetylspermine, which gave a good yield, is also described. The reaction mixture, containing N1-[14C]acetylspermine and tissue homogenate, was incubated for the enzyme reaction and applied to a minicolumn of Amberlite CG-50. The reaction product 3-[14C]-acetamidopropanal did not adsorb to the column, but passed through it; thus the eluate could be directly subjected to liquid scintillation counting. The blank levels were low and relatively constant even with crude tissue homogenates. The detection limit obtained was 0.05 nmol per tube. This method is simple, highly sensitive, and highly specific.

Animals↗
PubMed1990

Failure to verify the presence of pyrroloquinoline quinone (PQQ) in bovine plasma amine oxidase by gas chromatography/mass spectrometry.

The presence of covalently bound pyrroloquinoline quinone (PQQ) in bovine plasma amine oxidase (BPAO) was examined by the use of gas chromatography/mass spectrometry. The enzyme was subjected to proteolysis with proteinase in the presence of [U-13C]PQQ as an internal standard. After isolation and derivatization of PQQ with phenyltrimethylammonium hydroxide, molecular peaks at m/z 448 and 462 were used for detection of PQQ and [U-13C]PQQ, respectively, by selected ion monitoring (SIM). In the SIM profile, although the sample extract obtained from BPAO treated with proteinase clearly showed the peak at m/z 462 for the internal standard, there were no peaks detectable at m/z 448, showing the absence of PQQ in the proteolysis digest of BPAO. Thus, our results do not support the claim that BPAO contains covalently bound PQQ in its structure.

Amine Oxidase (Copper-Containing)↗
PubMed1990

Extractions of pyrroloquinoline quinone from crude biological samples.

The best conditions for extractions of free pyrroloquinoline quinone (PQQ) from crude biological samples were investigated with various organic solvents and Sep-Pak C18 cartridges. PQQ was measured with use of its native fluorescence in aqueous solution. PQQ was well extracted into n-butanol under acid conditions, and addition of NaCl did not improve the solvent extraction. PQQ, which had been extracted into n-butanol, could be re-extracted into an aqueous phase by addition of either n-heptane or pyridine, or combination of them. PQQ, which had been adsorbed to Sep-Pak C18 cartridges, could be eluted with a mixture of pyridine and water with very excellent recovery. The recovery of 1 micrograms PQQ, which had been added to 1 g human liver, brain and 1 ml plasma and had undergone the n-butanol and the Sep-Pak extractions, was 50, 75 and 105%, respectively. From the blank fluorescence, endogenous levels of free PQQ in human liver, brain and plasma were found not greater than 0.41, 0.08 and 0.13 micrograms/g or ml, respectively, if present.

Brain Chemistry↗
PubMed1990

Anesthetic influence on myocardial energy metabolism during hemorrhagic shock in rats.

Twenty-eight male Wistar rats were used to assess the influence of inhalation anesthetics on myocardial energy metabolism during hemorrhage. They were anesthetized with pentobarbital and divided into four groups: a control group and three others which received 1.2% halothane, 2.2% enflurane or 1.4% isoflurane, respectively. Following a 15-min stabilization period, blood was gradually withdrawn over a 5-min period from a femoral artery. Systolic blood pressure was maintained at 40 mmHg for 30 min. Immediately after hemorrhage, the heart was removed and myocardial metabolites (ATP, ADP, AMP, lactate and glycogen) were measured by the enzymatic methods. Although no significant differences could be detected in ADP, AMP and lactate among the groups, there were significant increases of ATP content in rats receiving halothane and isoflurane when compared with the controls. There were also differences in myocardial glycogen content between the control group and those receiving isoflurane with those receiving halothane or enflurane. These results suggest that halothane or isoflurane may be more desirable than enflurane for maintenance of anesthesia during hypovolemia.

Adenosine Triphosphate↗
PubMed1990

Positive- and negative-ion mass spectrometry and rapid clean-up of some carbamate pesticides.

Positive-ion electron impact (PIEI), positive-ion chemical ionization (PICI) and negative-ion chemical ionization (NICI) mass spectra of 9 carbamate pesticides are presented. In the PIEI mode, the spectra showed small molecular peaks, intense or base peaks due to M - CH3NHCO + H and peaks at m/z 58 due to CH3NHCO. In the PICI mode, peaks due to M + H, M + C2H5, M - CH3NHCO + 2H, CH3NHCO(m/z 58) and M-28 appeared. The cations at m/z 58 found in both PIEI and PICI modes seem very useful for screening of a carbamate. In the NICI mode, the spectra showed peaks due to M - CH3NHCO and characteristic anions appearing at mass numbers higher than molecular ones, which were probably due to dimerization of [M - CH3NHCO]-followed by hydrogen attachment. Carbamates, which had been added to urine, plasma, whole blood, the liver, kidney and brain, could be rapidly isolated by use of Sep-Pak C18 cartridges with chloroform as an elution solvent. They could be detected by wide-bore capillary gas chromatography with a SPB-5 column, with satisfactory separation from impurities in their underivatized forms.

Body Fluids↗
PubMed1990

A stimulus-activated conductance in isolated taste epithelial membranes.

Membrane vesicles isolated from the cutaneous taste epithelium of the catfish were incorporated into phospholipid bilayers on the tips of patch pipettes. Voltage-dependent conductances were observed in approximately 50% of the bilayers and single-channel currents having conductances from 8 to greater than 250 pS were recorded. In 40% of the bilayers displaying no voltage-dependent conductances, micromolar concentrations of L-arginine, a potent stimulus for one class of catfish amino acid taste receptors, activated a nonselective cation conductance. The L-arginine-gated conductance was concentration-dependent, showing half-maximal activation in response to approximately 15 microM L-arginine. L-Arginine-activated channels had unitary conductances of 40-50 pS and reversed between -6 and +18 mV with pseudointracellular solution in the pipette and Ringer in the bath. L-Alanine, a potent stimulus for the other major class of catfish amino acid taste receptors, did not alter bilayer conductance. D-Arginine, which is a relatively ineffective taste stimulus for catfish but a good cross-adapter of the L-arginine-induced neural response, had no effect on bilayer conductance at concentrations below 200 microM. However, increasing concentrations of D-arginine from 1 to 100 microM progressively suppressed the L-arginine-activated conductance, suggesting that D-arginine competed for the L-arginine receptor, but did not activate the associated cation channel. This interpretation is consonant with recent biochemical binding studies in this system. These results suggest that L-arginine taste receptor proteins in the catfish are part of or closely coupled to cation-selective channels which are opened by L-arginine binding.

Alanine↗
PubMed1990

Synthesis and antiarrhythmic activity of 5,11-dihydro[1]benzoxepino[3,4-b]pyridines.

During further modification of the new antiulcer agent 5 (KW-5805), a 5,11-dihydro[1]benzoxepino[3,4-b]pyridine derivative, we found that some new derivatives had antiarrhythmic activity. So we continued synthesis and evaluation of a series of 5-substituted 5,11-dihydro[1]benzoxepino[3,4-b]pyridines for antiarrhythmic activity in chloroform-induced ventricular arrhythmias in mice and in ouabain-induced ventricular arrhythmias in dogs. In chloroform-induced ventricular arrhythmias, the 7-methoxy group played an important role in activity and the type of terminal side chain at position 5 had not obvious effect on potency. On the other hand, in ouabain-induced ventricular arrhythmias, the structure-activity relationship was highly specific and only four compounds, 9, 30, 34, and 35, were effective. Compound 9,5-[[2-(diethylamino)ethyl]amino]-7-methoxy-5,11-dihydro[1] benzoxepino[3,4-b]pyridine 1.5-fumarate, which exhibited low affinity for muscarinic acetylcholine receptors and a high ED100(mydriasis)/ED50(antiarrhythmic activity) ratio, was selected for further development and clinical evaluation as KW-3407. The synthesis and antiarrhythmic activity of optically active 9 is described. The order of potency of antiarrhythmic activity in ouabain-induced ventricular arrhythmias in dogs was (-)-9, (+/-)-9, and (+)-9.

Animals↗
PubMed1990

Large enhancement of canine taste responses to sugars by salts.

The effects of changed ionic environments on the canine taste responses to sugars were examined by recording the activity of the chorda tympani nerve. a) The responses to various sugars were greatly enhanced by the presence of salts having monovalent cations such as Na+, K+, choline+, or Tris+. The responses to sugars were suppressed by high concentrations of salts. (b) The presence of 100 mM NaCl in fructose solution did not affect the maximal response and changed the Hill constant for the concentration-response relationship from 1.3 to 2.4. (c) CaCl2 greatly enhanced the response to fructose, while MgCl2 exhibited practically no effect. The presence of 20 mM CaCl2 in fructose solution changed the Hill constant from 1.2 to 2.4. (d) CaCl2 suppressed the responses to 0.5 M sugars except for fructose and sucrose and enhanced the responses to all sugars examined at 1 M. In the glucose response, the slope of the concentration-response curve was increased by the presence of CaCl2. Here the curve in the absence of CaCl2 intersected with that in the presence of CaCl2, indicating that CaCl2 suppressed the response to glucose of low concentrations and enhanced that of high concentrations. (e) The enhancement of the sugar responses by salts was not simply explained in terms of ionic permeability at the apical membranes of taste cells. The enhanced and suppressed effects of salts on the sugar responses were interpreted in terms of the cooperativity between receptor molecules for sugars.

Animals↗
PubMed1990

Functional and metabolic effects of bupivacaine and lignocaine in the rat heart-lung preparation.

We have examined the effects of bupivacaine and lignocaine on myocardial metabolism in the rat isolated heart-lung preparation. Bupivacaine 1, 5 or 25 micrograms ml-1 or lignocaine 4, 20 or 100 micrograms ml-1 was administered 5 min after the start of perfusion. Both bupivacaine 25 micrograms ml-1 and lignocaine 100 micrograms ml-1 reduced heart rate significantly. Bupivacaine 25 micrograms ml-1 was associated with a higher incidence of arrhythmias than the other groups. Three hearts in the bupivacaine 25 micrograms ml-1 group (n = 8) and two hearts in the lignocaine 100 micrograms ml-1 group (n = 8) failed (zero cardiac output) at the end of the experiment. Although there were no significant differences in myocardial lactate and glycogen concentrations between groups, ATP content in the bupivacaine 25 micrograms ml-1 and lignocaine 100 micrograms ml-1 groups was significantly less than that in the control group. The results suggest that myocardial depression and subsequent metabolic deterioration occurred with both the high doses of local anaesthetics; these findings do not account for the apparent increased cardiotoxicity of bupivacaine.

Adenosine Triphosphate↗
PubMed1990

Large synergism between monosodium glutamate and 5'-nucleotides in canine taste nerve responses.

The taste responses to the "umami" substances such as monosodium glutamate (MSG), GMP, and IMP were recorded from the chorda tympani nerve of mongrel dogs and beagles. A large synergism was observed between MSG and two species of nucleotides (GMP and IMP) in most mongrel dogs and between MSG and three species of nucleotides (GMP, IMP, and AMP) in beagles. The extent of the synergism between MSG and the nucleotides was much larger than that observed in any other animals examined except for humans. In the presence of GMP, the response magnitude of the chorda tympani nerve to MSG was increased but that to NaCl, HCl, sucrose, quinine, and glycine was unchanged. It was concluded that the canine taste responses to the umami substances closely resemble those in humans, and the dog is a suitable animal model for studies on the responses to the umami substances.

Animals↗
PubMed1990

Quantitative immunogold localization of Na+,K(+)-ATPase alpha-subunit in the tympanic wall of rat cochlear duct.

Ultrastructural localization of Na+,K(+)-ATPase was quantitatively investigated in the tympanic wall of rat cochlear duct by use of the protein A-gold method, using an affinity-purified antibody against the alpha-subunit of rat kidney Na+,K(+)-ATPase. A moderate number of gold particles were found on the basolateral membrane of the interdental cells of the spiral limbus. A small number of gold particles were found on the basolateral surfaces of the border cells and Hensen's cells. On the inner and outer sensory hair cells, however, the plasma membranes were rarely labeled by gold particles. The general pattern of labeling densities in cochlear structures determined here and in a previous communication from our laboratory shows good correlation with the distribution of Na+,K(+)-ATPase activity as previously estimated biochemically, cytochemically, and autoradiographically.

Animals↗