Biomedical subjects

H Watari

Publications and source records attributed to H Watari.

At least 109 records · Page 6Linked to original sources

PubMed1985

Augmented energy consumption during early systole as a mechanism of cyclical changes in high-energy phosphates in myocardium assessed by phosphorus nuclear magnetic resonance.

To evaluate the underlying mechanism of oscillatory changes in energy-related metabolites during a cardiac cycle, intramyocardial creatine phosphate (CP), inorganic phosphate (Pi), adenosine triphosphate (ATP), adenosine diphosphate (ADP) and pH were measured in isolated rat hearts by the phosphorus nuclear magnetic resonance spectrometry method gated by the left ventricular pressure. These were perfused with modified Krebs-Henseleit solution containing pyruvate. CP decreased at both early- and end-systole whereas Pi and ADP increased in these phases. Both ATP and intracellular pH decreased significantly at end-systole. The indices of the affinity for ATP hydrolysis [Pi]/[CP] and [ADP] [Pu]/[APT] increased at early-systole, indicating that a large consumption of high-energy phosphates occurred at early-systole. Furthermore, the cyclical changes in ATP, CP and Pi were augmented in the high contractile state induced by infusion of isoproterenol. These results strongly suggest that the cyclical changes in the energy-related metabolites during a cardiac cycle are caused mainly by an augmentation of energy consumption during early-systole and an insufficient energy supply during systole, probably due to the slow intracellular transport of CP.

Adenosine Diphosphate↗

PubMed1985

31P-NMR study of dog submandibular gland in vivo and in vitro using the topical magnetic resonance.

The topical magnetic resonance (TMR) was used to study the phosphorous metabolism of a dog's submandibular gland during acetylcholine stimulation. The experiments were carried out under two conditions. One was a normal blood supply (in vivo) and the other was vascular perfusion with the artificial perfusate (in vitro). The levels of phosphorous compounds in the gland were obtained for 31P-NMR spectra of the TMR. The saliva was secreted in the both conditions, though the salivary flow under the in vivo condition was higher than in vitro. During salivary secretion, only the levels of creatine phosphate decreased under in vivo condition, while the levels of creatine phosphate and ATP decreased and the levels of inorganic phosphate increased in in vitro cases. It was concluded that the decrement of creatine phosphate during the salivary secretion indicates the acceleration of the energy metabolism in the submandibular gland.

Acetylcholine↗

PubMed1985

Spontaneous posterior bulbar perforation of congenital scleral coloboma and its surgical treatment: a case report.

A 35-year-old male presented with abrupt hypotonic oculopathy caused by a spontaneous bulbar perforation, due to a scleral defect in the equatorial area of the nasal side of the left eye. The scleral defect was surgically repaired using lyophilized homologous dura mater encephali and fibrin glue (Tisseel). Highly satisfactory results were obtained. The pathogenesis of this scleral defect was suspected to involve complex factors related to abnormal retinal development and abnormal ocular muscles. Such a case has not been reported previously.

Adult↗

PubMed1985

Acute effects of the new oral angiotensin converting enzyme inhibitor 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-phenylalanine (Alacepril) in essential hypertension.

In 15 patients with mild-to-moderate essential hypertension a new orally active angiotensin converting enzyme inhibitor, 1-(D-3-acetylthio-2-methylpropanoyl)-L-prolyl-L-phenylalanine (Alacepril), was administered with a single oral dose of 50 mg to evaluate its antihypertensive effect. Following Alacepril plasma angiotensin converting enzyme (ACE) activity was inhibited by approximately 75% within 2 h. Plasma renin activity increased slightly whereas plasma levels of aldosterone decreased significantly. Blood pressure fell markedly not only in patients with high renin levels but also in those with low renin levels. Nevertheless, the magnitude of blood pressure reduction was correlated with the pre-treatment plasma renin values (r = -0.602, p less than 0.05 systolic, r = -0.667, p less than 0.01 diastolic). No relevant changes in pulse rate was observed. These findings demonstrate that in essential hypertension the novel orally active ACE inhibitor Alacepril exerts marked antihypertensive effect, which may offer a new effective approach to treatment of hypertension.

Administration, Oral↗

PubMed1985

Biochemical identification of renin in human pheochromocytoma.

A high activity of renin was demonstrated in human pheochromocytoma tissue. This activity was inhibited by specific antibody raised against human renal renin, indicating that it was not due to the nonspecific actions of proteases such as cathepsin D. The specific renin shared some biochemical features with well-known kidney renin, such as molecular weight (47,000 daltons), optimum pH (6.0), the presence of trypsin-activatable inactive renin, and glycoprotein nature. However, the isoelectrofocusing pattern of renin from the pheochromocytoma differed from that of kidney and plasma renins hitherto reported, a discrepancy which could be interpreted as evidence for endogenous synthesis of the enzyme. Furthermore, angiotensin converting enzyme activity was found in the tissue. Since pheochromocytoma is considered to be of neural crest origin, these results provide biochemical and immunological evidence for the presence of the renin-angiotensin cycle within human neuronal cells.

Adolescent↗

PubMed1985

Measurements of in vivo 31P nuclear magnetic resonance spectra in neuroectodermal tumors for the evaluation of the effects of chemotherapy.

The effects of chemotherapy on living tumor tissue in hamsters and rats were investigated by measuring the 31P nuclear magnetic resonance spectra using topical magnetic resonance. Human neuroblastoma, human glioblastoma, and rat glioma tumor cells were inoculated s.c. in the lumbar region of the animals. After the diameter of the tumors increased to 1.5 cm, in vivo 31P nuclear magnetic resonance spectra were measured selectively in the tumors with a TMR-32 spectrometer. Adenosine triphosphate, inorganic phosphate (Pi), phosphodiester, and phosphomonoester peaks were observed. The phosphocreatine peak was hardly detectable, adenosine triphosphate and phosphomonoester peaks were high, and tissue pH, calculated from the chemical shift of Pi, declined. Regardless of the tumor origin or the histological type, the spectral pattern of each neuroectodermal tumor was found to be essentially the same. After i.v. injection of a large dose of a chemotherapeutic agent, adenosine triphosphate peaks decreased and Pi increased gradually, resulting in a dominant Pi peak pattern after 6 to 12 hours. However, during the same period, there were no observable changes in the spectra of normal organs. These findings indicated that the drugs have a selective and direct action on the energy metabolism of tumor cells. With lower drug doses, no remarkable changes were seen in the spectrum. Measurement of in vivo 31P nuclear magnetic resonance spectra is valuable not only to investigate the energy metabolism in tumor tissue but also to evaluate the effects of chemotherapy.

Adenosine Triphosphate↗

PubMed1985

Sodium dodecyl sulfate-bovine plasma albumin complex. Structural transition from native to relatively compact globule forms with mobile side chains in acidic region--N-F transition.

The acid-induced isomerization (the N-F transition) and expansion of sodium dodecyl sulfate-bovine plasma albumin complex (ADm; m, molar ratio of added sodium dodecyl sulfate to bovine plasma albumin; O less than or equal to m less than or equal to 12) were studied by measuring CD-resolved secondary structure, fluorescence polarization and life-time of tryptophyl fluorophors, acid-titration with the electrostatic correction for the surface potential, 1H-n.m.r. spectra and cross relaxation time between irradiated and observed protons. The immobilization of tryptophyl fluorophors observed in the F-form of AD0 was suppressed in the F-form of AD10. The acidtitration analysis of AD12 showed non salt-bonding between carboxylate groups and cationic side chains in the F-form, as in the case of AD0, indicating charged side chains being presumably mobile. 1H-n.m.r. spectra and cross relaxation times between irradiated and observed protons in the F-form of AD10 indicated the increase in the local motion. On the other hand, AD10 and AD12 did not show any significant change in the CD-resolved secondary structure in the N-F transition region. The F-form of AD10 or AD12 may therefore be the moltenglobule state which has secondary structure similar to the N-form of the complexes with fluctuating tertiary structure (side chains).

Animals↗

PubMed1984

In vivo measurement of energy metabolism and the concomitant monitoring of electroencephalogram in experimental cerebral ischemia.

The energy metabolites in rat brain in vivo were measured by using topical magnetic resonance (TMR) during the whole course of ischemia, in combination with the concomitant monitoring of electroencephalogram (EEG). Immediate loss of high energy phosphorus compounds, phosphocreatine (PCr) and ATP, resulted in the flattening of EEG after the induction of ischemia. PCr and ATP returned to almost normal level 30 min after recirculation of the ischemic brain, but EEG showed no recovery and the abnormality lasted for 12 h. The measurement of in vivo 31P-NMR is essential for the decision of the convalescence of cellular function in the brain.

Adenosine Diphosphate↗

PubMed1984

Measurements of in vivo energy metabolism in experimental cerebral ischaemia using 31P-NMR for the evaluation of protective effects of perfluorochemicals and glycerol.

Effects of perfluorochemical (PFC) and glycerol on energy metabolism in cerebral ischaemia were examined by the sequential measurements of in vivo 31P-NMR spectrum using topical magnetic resonance (TMR). Experimental cerebral ischaemia was induced in forty-five Wistar rats by a four-vessel occlusion method. The 31P-NMR spectrum and the EEG were monitored during preischaemic and ischaemic periods and after circulation was restored for various periods up to 240 min. There were several peaks in the 31P-NMR spectrum of the preischaemic rat brain; beta-ATP, alpha-ATP, gamma-ATP, phosphocreatine (PCr), phosphodiesters, inorganic phosphate (Pi) and sugar phosphate. As soon as the ischaemia was induced, PCr and ATP decreased and Pi increased. The chemical shift of the increased Pi peak decreased, showing acidosis of the brain tissue. After circulation was restored following the 30 min ischaemia, recovery of the 31P-NMR spectrum occurred within 30 min in all sixteen untreated rats. Recovery of the 31P-NMR spectrum was induced by recirculation only in half of the six rats in the untreated 60 min ischaemia group. None of the six rats in the untreated group showed recovery of the spectrum after 120 min ischaemia. When 20% Fluosol-DA was administered at a dose of 20 ml/kg before the induction of ischaemia, all eight rats showed recovery of the spectrum after 120 min ischaemia. Moreover, four of six rats treated with both PFC and glycerol showed temporary recovery even after 240 min ischaemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Diphosphate↗

PubMed1984

Gel chromatographic evidence for the participation of the higher polymers in the self-association system of a flavoenzyme D-amino acid oxidase.

The self-association of subunits of D-amino acid oxidase holoenzyme was studied by high-speed gel filtration with a short column of TSK-GEL G3000 SW in 0.1 M sodium pyrophosphate (pH 8.3) at 25 degrees C. Over the range of the peak concentrations of 0.009-4.45 mg/ml in the presence of FAD the apparent Stokes radii increased with an increase of the concentrations and did not level off. The largest value obtained in this study was 61.5 A. This would correspond to that calculated for the hexamer with linear subunit arrangement which has the largest Stokes radius among the various arrangements. These results provide the first gel chromatographic evidence that the higher polymers greater than the dimer participate in the self-associating system of the enzyme.

Animals↗

PubMed1984

31P-topical nuclear magnetic resonance (31P-TMR) studies of cardiotoxic effects of 5-fluorouracil (5-FU) and 5'-deoxy-5-fluorouridine (5'-DFUR).

Using the 31P-topical nuclear magnetic resonance method (TMR), an attempt was made to determine the myocardial high-energy phosphate compounds (HEP) contents under in situ conditions in closed-chest animals, and the effects of opening the thorax on the myocardial energy metabolism were studied comparing the cardiotoxic effects of 5-fluorouracil (5-FU) in closed-chest and open-chest animals. It was found that the depletion of myocardial HEP produced by 5-FU was much more marked in open-chest animals than in closed-chest ones, indicating the necessity of conducting the experiments in closed-chest animals for the proper evaluation of the cardiotoxicity of certain types of compounds. Therefore, the cardiotoxicity of a prodrug of 5-FU was assessed in closed-chest animals, and it was found to be less cardiotoxic than 5-FU.

Adenosine Triphosphate↗

PubMed1984

Effects of Na+ depletion on fluid secretion and levels of phosphorus compounds as measured by 31P-NMR in perfused canine mandibular gland.

The dependency of fluid secretion on extracellular Na+ and the levels of phosphorus compounds were studied in the perfused canine mandibular gland (using 31P-NMR). During control perfusion, the resting levels of creatine phosphate (CP) and ATP were 0.62 +/- 0.05 mmol . kg-1 gland and 0.42 +/- 0.04 mmol . kg-1 (mean +/- S.E., n = 9), respectively. Acetylcholine (Ach; 1 mumol . l-1 for 3 min) induced a salivary secretion and decreased the CP level. When Na+ in the perfusate was completely replaced with Li+, Ach induced only a minimal salivary secretion and no change in the ATP and CP levels. Restitution of Na+ to the perfusion, even without added Ach, caused a decrease in ATP and CP, and a small increase in salivary secretion. These results suggest that the activity of Na+/K+ ATPase is increased inversely via a rise of the intracellular Na+ concentration and that the salivary secretion is induced not only by added secretagogues but by an increase in the Na+ entry without added secretagogues.

Adenosine Triphosphate↗

PubMed1984

In vivo 31P-NMR studies on aerobic recovery of frog muscle following tetanus.

Aerobic recovery after a 60-sec tetanus of skeletal muscle of frog was studied using the in vivo 31P-NMR method with a topical magnetic resonance spectrometer (TMR) at 17 degrees C. Creatine phosphate recovered with a time constant of about 25 min-1. Sugar phosphates increased by the Pasteur effect, and saturated at about 4.5 mmol/kg muscle. The high level of the sugar phosphates was sustained during the following 60 min.

Adenosine Triphosphate↗

PubMed1984

[Research on experimental cerebral infarction in cats with in vivo TMR (topical magnetic resonance) approach].

Metabolic changes in the ischemic brains of cats were investigated in vivo with high energy phosphate compounds as parameters by using a topical magnetic resonance (TMR) spectrometer. The experimental focal cerebral ischemia was made in four cats by modifying the method of O'Brien and Waltz. The stem of left middle cerebral artery was exposed and set the occlusive device 5-7 days before the in vivo measurement. 31P-NMR spectrum was taken under general anesthesia with Ketamine HCI and with decreased blood flow. The following points must be considered in obtaining 31P-TMR spectrum in a cat brain: Firstly, as much muscle as possible must be removed from the detective area because it contains phosphate compounds. Our experiment showed that bone and blood had little or no effect on the 31P-TMR spectrum. Secondly, although same procedure was repeated, it was difficult to obtain constant ischemic lesion; in site and size. The detective area in setting was not changed in the particular area. However there was a possibility of the detective area also including various non-ischemic regions. Thirdly, 31P-TMR spectrum had several peaks in a cat brain; which were sugar phosphate, inorganic phosphate, phosphodiesters, phosphocreatine, gamma-, alpha-, beta-ATP in the pre-occlusive conditions. These peaks did not appear in clear volume separation with one another. We drew the perpendicular line from through between two neighbour peaks to the horizontal base line and artificially divided two peaks. The area of each peak did not represent correctly the density of each component. Fourthly, unnecessary components were rationalistically excluded from the 'raw' spectrum.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

Resonance Raman study on the flavin in the purple intermediates of D-amino acid oxidase.

Resonance Raman (RR) spectra were measured for the purple intermediates of D-amino acid oxidase reconstituted with isotopically labelled FAD's, i.e., [4a-13C]-, [4,10a-13C2]-, [2-13C]-, [5-15N]-, and [1,3-15N2]flavin adenine dinucleotides, and compared with those with the native enzyme. The RR lines around 1605 cm-1 with D-alanine or D-proline as a substrate and at 1548 cm-1 with D-alanine undergo isotopic shifts upon [4a-13C]- and [4,10a-13C2]-labelling. These lines are assigned to the vibrational modes associated with C(10a) = C(4a) - C(4) = O moiety of reduced flavin, providing the first assignment of RR lines of reduced flavin and conclusive evidence that reduced flavin is involved in this intermediate.

Animals↗

PubMed1983

Phosphorus nuclear magnetic resonance of perfused salivary gland.

Phosphorus nuclear magnetic resonance (31P-NMR) was used for the sequential measurement of phosphorus energy metabolites in perfused canine submandibular gland. Under resting conditions, ATP and creatine phosphate levels were 0.42 +/- 0.11 mM and 0.62 +/- 0.16 mM (mean +/- S.D., in nine glands). When perfusion of the gland was stopped, the tissue contents of ATP and creatine phosphate decreased, that of ADP increased and tissue pH decreased. Restarting perfusion led to recoveries of the tissue content of the phosphorus compounds and tissue pH to normal. Acetylcholine administration induced secretion of saliva, decreased the level of ATP, creatine phosphate and tissue pH, and increased the ADP level.

Acetylcholine↗

PubMed1983

Intracellular pH determination by a 31P-NMR technique. The second dissociation constant of phosphoric acid in a biological system.

To evaluate the accuracy of pH determination by 31P-NMR, factors which influence the pK value of phosphate were appraised on the basis of the titration of 1 mM phosphate buffer solution. When the method is used for the determination of cytoplasmic pH, ionic strength is the major factor causing shifts of apparent pK (pK') value, and the magnitude of the shift can be predicted from the ionic strength calculated by means of the Debye-Hückel equation. Ions (Na+, K+, Mg2+, and Ca2+) and salivary protein affected the pK' value by 0.1 to 0.3 units in solution with a given ionic strength depending on the species of ion. The form of the titration curve varied with temperature. Based on these results, the value of 6.75 was obtained with the uncertainty of 0.12 for the intracellular pK' of frog muscle at 24 degrees C.

Animals↗

PubMed1983

On the structures of flavoprotein D-amino acid oxidase purple intermediates. A resonance Raman study.

Resonance Raman (RR) spectra were obtained in H2O or D2O solution for the purple intermediates of D-amino acid oxidase (DAO) with isotopically labeled substrates, i.e., [1-13C]-, [2-13C]-, [3-13C]-, [15N]-, and [3,3,3-D3]alanine; [carboxyl-13C]- and [15N]proline. RR spectra were also measured for the intermediates of DAO reconstituted with isotopically labeled FAD's, i.e., [4a-13C]-, [4,10a-13C2]-, [2-13C]-, [5-15N]-, and [1,3-15N2]FAD in D2O. The isotopic shift of the 1692 cm-1 band upon [15N]- or [2-13C]-substitution of alanine indicates that the band is due to the C = N stretching mode of an imino acid derived from D-alanine, i.e., alpha-iminopropionate. The 1658 cm-1 band with D-proline was also assigned to the C = N stretching mode of an imino acid derived from D-proline, i.e., delta 1-pyrrolidine-2-carboxylate, since the band shifts to 1633 cm-1 upon [15N]-substitution and its stretching frequency is generally found in this frequency region. Since the band shifts to low frequency in D2O, the imino acid should have a protonated imino group such as the C = N+1H form. The intense band at 1363 cm-1 with D-alanine was assigned to a mixing of the CO2- symmetric stretching and CH3 symmetric deformation modes in alpha-iminopropionate, based on the isotope effects. The 1359 cm-1 band with D-proline has probably contributions of CO2- symmetric stretching and CH2 wagging, considering the isotope effects with [carboxyl-13C]proline. The 1359 cm-1 band with D-proline was split into 1371 cm-1 and 1334 cm-1 bands in D2O. As this splitting of the 1359 cm-1 band with D-proline in D2O can not be interpreted only by the replacement of the C = N+1-H proton by deuterium, the carboxylate of the imino acid probably interacts with the enzyme through some proton(s) exchangeable by deuterium(s) in D2O. The bands around 1605 cm-1 which shift upon [4a-13C]- and [4,10a-13C2]-labeling of FAD are derived from a fully reduced flavin, because the isotopic shifts of the band are very different from those of the bands of oxidized or semiquinoid flavin observed near 1605 cm-1.(ABSTRACT TRUNCATED AT 400 WORDS)

Alanine↗