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Biomedical subjects

H Watari

Publications and source records attributed to H Watari.

At least 73 records · Page 4Linked to original sources
PubMed1987

Biochemical characterization of angiotensin-converting enzyme in human neuroblastoma tissue.

High activity of angiotensin-converting enzyme was demonstrated in human neuroblastoma tissue. This activity required the presence of chloride ion and was almost completely inhibited by a specific converting enzyme inhibitor captopril (10 nM), indicating that the activity measured is indeed angiotensin-converting enzyme. Furthermore, the biochemical features of the enzyme were closely similar to the well-known properties of human lung converting enzyme, such as molecular weight (290,000), optimum pH (8.0-8.5), the presence of glycoprotein residues, and dependence on chloride ion concentration. These results provide definitive evidence for the presence of true angiotensin-converting enzyme in human neuroblastoma tissue.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1987

A hitherto unreported case of 21-hydroxylase deficiency associated with Bartter's syndrome and a balanced 6-9 translocation.

A description is given of a girl with the non-salt-losing type of congenital adrenal hyperplasia (CAH) and with Bartter's syndrome. In addition, the patient had a balanced translocation between 6q and 9p. Although the possibility cannot be ruled out fully that an excess of progesterone might modify the renin-aldosterone axis to some extent, the finding that dexamethasone therapy improved the clinical features of CAH but failed to correct metabolic disorders in electrolyte balance strongly suggests the coexistence of the two clinical entities. Chloride transport at the distal tubule was impaired moderately in the patient, which suggests that her defective reabsorption of chloride was responsible for the impaired renal handling of sodium that is often observed in patients with Bartter's syndrome. It appears that the reciprocal translocation is unrelated to both CAH and Bartter's syndrome since the same translocation was found in her healthy mother and siblings.

Adolescent↗
PubMed1987

Treatment of pheochromocytoma with dilevalol.

Dilevalol, an alpha- and beta-blocking agent, has been evaluated in two patients with pheochromocytoma. Dilevalol could be a useful agent for the treatment of pheochromocytoma, especially for the adrenaline-dominant type.

Administration, Oral↗
PubMed1986

Biochemical evidence for existence of immunoreactive renin in human prolactinoma tissue.

High activity of renin was demonstrated in human prolactinoma tissue. This activity was almost completely inhibited by specific antibody raised against human renal renin, indicating that it was not due to the nonspecific action of proteases. The specific activity of renin was 5.04 ng of angiotensin I generated/mg of protein per h, comparable to that of the pituitary tissue prepared from postmortem human subjects. The biochemical properties of the prolactinoma renin were generally similar to those of well-known kidney enzyme, such as molecular mass (Mr = 46,000), optimum pH (6.0), and glycoprotein nature. However, the isoelectric points (pI) of the prolactinoma renin (pI = 4.90, 5.04, 5.24 and 5.41) differed somewhat from those of plasma and kidney renins reported hitherto. These results indicate that true renin can be produced in human prolactinoma tissue.

Chromatography, Affinity↗
PubMed1986

[A case of 21-hydroxylase deficiency and Bartter's syndrome associated with a balanced 6-9 translocation].

A 17-year-old female weighing 37 kg and 140 cm in height was referred to our hospital for evaluation of dwarfism and primary amenorrhea. She was delivered with 3350 g in weight and 50 cm in height after a ten month pregnancy without complications. No abnormal findings were revealed in physical appearance except critomegaly. Episodes of nausea, vomiting and dehydration were rare throughout her childhood, but she had a tendency to salt craving. At the age of 14, her height was 140 cm. On admission, her physical development was markedly retarded for her age, except external genitalia. Diffuse pigmentations on the trunk and extremities were observed. Her blood pressure was normal (112/62 mm Hg). Serum potassium concentration was 2.9 mEq/L. Arterial-blood gas analysis revealed metabolic alkalosis. Both of renin activity (PRA) and aldosterone concentration (PAC) in plasma at rest were markedly elevated to 15.5 ng/ml/h and 107.1 ng/dl, respectively. The plasma concentrations of pregnenolone (1449 ng/dl), progesterone (178 ng/dl), 17-OH-pregnenolone (1613 ng/dl), 17-OH-progesterone (180 ng/dl), dehydroepiandrosterone (3706 ng/dl), androstendione (824.6 ng/dl) and testosterone (900 ng/dl) were high, whereas deoxycorticosterone (15.7 ng/dl), corticosterone (0.65 microgram/dl) and cortisol (6.8 micrograms/dl) were within normal limits. Urinary 17-KS excretion showed high levels between 65.7 and 109.4 mg/day, while urinary 17-OHCS excretion was normal (5.7-7.0 mg/day). Vascular response to angiotensin II (A-II) was attenuated. Distal fractional chloride reabsorption was decreased (CH2O/CH2O+CCl = 0.62, normal: 0.92 +/- 0.04). Moderate hyperplasia of the juxtaglomerular cells was demonstrated in biopsy specimen of the kidney. Cytogenetic studies showed a 46, XX chromosome constitution with translocation of the long arm of chromosome 6 to the short arm of chromosome 9. Her mother as well as younger brother and sister, whose electrolytes and arterial-blood gas analysis showed normal values, had chromosomes with the same translocation. Treatment with dexamethasone (2 mg/day) reduced every adrenal steroids to normal range, but PRA and PAC remained high levels. Furthermore, neither hypokalemic alkalosis nor vasoreactivity to exogenous A-II was improved. Indomethacin (75 mg/day) decreased urinary excretion of prostaglandin E2 from a high level of 738.4 ng/day to 433.4 ng/day and normalized metabolic alkalosis. Vascular response to A-II was moderately improved. However, serum potassium remained low.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1986

Demonstration and characterization of angiotensin-converting enzyme in human pituitary tissue.

High activity of angiotensin-converting enzyme was demonstrated in human pituitary tissue. This activity required the presence of chloride ion and was almost completely inhibited by a specific converting enzyme inhibitor captopril (10 nM), indicating that the activity measured is indeed angiotensin-converting enzyme. The specific activity of the enzyme was 1.68 +/- 1.20 nmol hippuric acid generated mg of protein-1 min-1 (mean +/- SD, for 11 specimens). The biochemical features of the enzyme were closely related to the well-characterized human lung converting enzyme, such as molecular weight (290,000), optimum pH (8.0-8.5), the presence of glycoprotein residues, and dependence on chloride ion concentration. These results provide definitive evidence for the presence of angiotensin-converting enzyme in human pituitary tissue.

Chlorides↗
PubMed1986

A resonance Raman study on the structures of complexes of flavoprotein D-amino acid oxidase.

Resonance Raman (RR) spectra were obtained for the purple complexes of D-amino acid oxidase (DAO) with D-lysine or N-methylalanine. RR spectra of a complex of oxidized DAO with the oxidation product of D-lysine or D-proline were also measured. The isotope shifts of the observed bands of the purple complex with D-lysine upon 13C- or 15N-substitution of lysine indicate that the ligand is delta 1-piperideine-2-carboxylate. That the band at 1671 cm-1 for the purple intermediate with N-methylalanine shifts to 1666 cm-1 in D2O solution indicates that the imino acid, N-methyl-alpha-iminopropionate, has a protonated imino group. Many bands due to a ligand in the RR spectra of the complex of oxidized DAO with an oxidation product can be observed below 1000 cm-1, but no band for the purple complex is seen in this frequency region. The band associated with the CO2-symmetric stretching mode of the product, such as delta 1-piperideine-2-carboxylate or delta 1-pyrrolidine-2-carboxylate, complexed with the oxidized DAO shifts in D2O solution. This suggests that the product imino acid interacts with the enzyme through some proton(s).

Alanine↗
PubMed1986

Continuous measurements of Na, Li, and Cl in the perfused salivary gland by use of NMR.

The present study was undertaken to measure tissue contents of Na, Li, and Cl non-invasively in the isolated perfused organ by nuclear magnetic resonance (NMR) using a broadband tunable probe. The NMR signals of 23Na, 7Li, and 35Cl from the isolated perfused rat mandibular gland were collected continuously and each spectrum was obtained for every 15 or 20 s. The Na concentration in the perfusate was varied by replacement with Li, and the resulting changes were monitored by measuring the signal intensities of the electrolytes. The time constant for Na exchange was slower following complete removal of extracellular Na than following its half replacement, suggesting that the Na extrusion by Na+/K+ ATPase was reduced by lowering the extracellular Na level. The time constant for Li exchange was slower than that for Na exchange. The level of Cl was nearly constant during experiment, except for a very slow increase in Cl, possibly resulting from increasing edema and/or intracellular Li storage.

Animals↗
PubMed1986

Antihypertensive effect of a new calcium channel blocker, FK 235, in essential hypertension.

The antihypertensive effect of a new calcium channel blocker (FK 235) were evaluated in 10 patients with mild-to-moderate essential hypertension. The study consisted of 4 weeks of placebo and 12 weeks of the drug, 2 to 4 mg twice a day. Overall systolic and diastolic blood pressures (mean +/- SE) were reduced from 173 +/- 4 to 158 +/- 2 mm Hg (p less than 0.001) and from 97 +/- 2 to 89 +/- 1 mm Hg (p less than 0.001), respectively, with a dose of 5.6 +/- 0.7 mg/day. No relevant changes in heart rate, body weight, and plasma levels of renin activity and aldosterone concentration were observed. No side effects were encountered during the therapy. Our data indicate that the novel active calcium channel blocker can be used as a safe, effective and well tolerated antihypertensive for the treatment of essential hypertension.

Adult↗
PubMed1986

Water structure in modified bovine plasma albumin (BPA) gel and bovine mercaptalbumin solution. 1H-n.m.r. studies.

Bovine plasma albumin Fr. V (BPA) has been known to contain small amounts of proteolytic enzyme. Wilson & Foster (1971) found a very limited and specific cleavage of BPA catalyzed by the enzyme with BPA in the F-form near pH 3.8, resulting in the formation of partially hydrolyzed BPA (BPA*). BPA* had a tendency to form a transparent gel at pD 4.0 (pD range of the F-form) above 8%, though proteolytic enzyme-free bovine mercaptalbumin (BMA) was in a transparent solution at pD 4.0 even at 12%. Water structures of the F-form of BMA in the solution state and of BPA* in the gel state were studied by measuring 1H-n.m.r. spectra, spin-lattice relaxation time (T1) and cross relaxation time (TIS) between irradiated and observed protons. Protein concentration-dependent changes of T1 of water protons indicated that the amount of hydrated water of BPA* in the gel state is far greater than that of the F-form of BMA in the solution state. TIS values from protein protons to water protons also indicated a large amount of hydration of BPA*, strong interaction between water and BPA* and rapid exchange between bound and bulk water in the gel state.

Animals↗
PubMed1985

[Evidence for the existence of inactive renin in the rat brain. Part II. Distribution of inactive renin in the brain of spontaneously hypertensive rats].

Inactive renin in the brain of spontaneously hypertensive rat was investigated. The results are as follows. Treatment with either trypsin or glandular kallikrein of the brain tissue extract caused a rapid and apparent increase in the renin activity at either 0 or 27 degrees C. The molecular weight of the active renin was estimated to be 41,000 or 50,000 daltons, while that of the trypsin-activatable inactive renin was found to be 44,000 or 57,000 daltons on a column chromatography with Sephadex G-100. The contents of the active renin was the highest in the hypothalamus, followed by the striatum, thalamus, midbrain, medulla oblongata, cerebral cortex and cerebellum, while the contents of the trypsin-activatable inactive renin was the highest in the hypothalamus, followed by the striatum, thalamus, cerebellum, midbrain, cerebral cortex and medulla oblongata. These results suggest that inactive renin(s) exist in the brain of spontaneously hypertensive rat. It seems likely that the brain renin-angiotensin system is modulated by the conversion of inactive to active renin(s), which, in turn, plays at least in part a role in the blood pressure regulation through generation of angiotensin II in spontaneously hypertensive rats.

Animals↗
PubMed1985

Multiple forms of immunoreactive renin in human pituitary tissue.

Immunoreactive renin was demonstrated in pituitary tissues of postmortem human subjects with different diseases. The specific immunoreactive renin activity comprised the majority of the tissue renin-like activity (mean, 83%), indicating the absence of nonspecific actions of proteases such as cathepsin D. We used three pituitary specimens with high levels of the specific renin activity for further biochemical characterization of the enzyme. Small differences were found in the molecular mass (45 K, 42 K and 37 K), binding to concanavalin A-Sepharose, and isoelectric points (pI) (4.72, 4.78, 4.86, 5.06, 5.28 and 5.44). These results seem to be interpreted as evidence for the presence of specific renin in the human pituitary with microheterogeneity.

Chromatography, Affinity↗
PubMed1985

Self-association mode of a flavoenzyme D-amino acid oxidase from hog kidney. I. Analysis of apparent weight-average molecular weight data for the apoenzyme in terms of models.

The self-association of D-amino acid oxidase apoenzyme in 0.1 M sodium pyrophosphate, pH 8.3, at 25 degrees C was studied by low-angle laser light scattering. The concentration (c) dependence of the apparent weight-average molecular weight (Mwapp) was determined over a wide concentration range of 0.04 to 6.1 mg/ml. The extrapolated Mwapp value, to zero enzyme concentration, corresponded to the Mr value of the monomer. The self-association mode of the apoenzyme was systematically explored with nonlinear least-squares analysis of the Mwapp versus c data. The simplest model that fitted the data well was a model of isodesmic indefinite self-association of the monomer with the isodesmic association constant of 0.467 +/- 0.034 liter/g. The monomer-dimer model proposed previously, but only in a low enzyme concentration range of less than 0.9 mg/ml at 5-20 degrees C (Henn, S. W., and Ackers, G. K. (1969) Biochemistry 8, 3829-3838), did not fit the Mwapp versus c data either in the limited low concentration range or in the whole concentration range examined at 25 degrees C. To test the validity of the chosen model, the observed sedimentation boundary profiles were compared with the idealized boundary profiles calculated for the better-fit models. The profile calculated with the model of the isodesmic indefinite self-association mechanism was qualitatively consistent with the observed ones. The utility of the nonlinear least-squares procedure for analyzing self-associating systems was demonstrated.

Animals↗
PubMed1985

Self-association mode of a flavoenzyme D-amino acid oxidase from hog kidney. II. Stoichiometry of holoenzyme association and energetics of subunit association.

The self-association pattern of D-amino acid oxidase holoenzyme in 0.1 M sodium pyrophosphate, pH 8.3, at 25 degrees C was examined by the low-angle laser light-scattering method. As to the results of nonlinear least-squares analysis of the apparent weight-average molecular weight (Mwapp) versus protein concentration (c) data, the following three models fitted equally well the data over the concentration range of 0.03-11.4 mg/ml: 1) the model of isodesmic indefinite self-association of the monomer where the dimerization constant differs from the isodesmic association constant, 2) the model which involves the dimerization of the monomer and isodesmic indefinite self-association of the dimer, and 3) the model which involves the trimerization of the monomer and isodesmic indefinite self-association of the trimer. In a more limited concentration range (0.3-11.4 mg/ml), a model of isodesmic indefinite self-association of the stable dimer where the dimer does not dissociate into the monomers cannot be excluded from the above three models. Measurements with the concentration range lowered to 0.03 mg/ml enabled us to exclude unequivocally the model involving such a stable dimer and to extrapolate the Mwapp data to the Mr of the monomer at infinite dilution as in the case of the apoenzyme. The observed sedimentation boundary profiles were qualitatively consistent with the idealized boundary profiles calculated with the model which involves the dimerization of the monomer and isodesmic indefinite self-association of the dimer, so this model is the most probable of the models examined. These results provide the first evidence that the association mode of the holoenzyme is different from that of the apoenzyme, i.e. isodesmic indefinite self-association of the monomer (Tojo, H., Horiike, K., Shiga, K., Nishina, Y., Watari, H., and Yamano, T. (1985) J. Biol. Chem. 260, 12607-12614). The overall linkage scheme, between binding of coenzyme FAD and subunit association, was considered, and the overall free energy change in each process in the scheme was calculated. The total stabilization energies of the intersubunit interaction in the holoenzyme relative to the apoenzyme were found to be -2.2 kcal/mol at the dimerization step and -0.5 kcal/mol at the step of the addition of the dimer to any 2i-mer (i = 1,2, ...).

Animals↗
PubMed1985

Observations of energy metabolism in neuroectodermal tumors using in vivo 31P-NMR.

The energy metabolism of living tumors in rats and hamsters were investigated by obtaining in vivo 31P-NMR spectra, and the effects of chemotherapy on tumors were evaluated by observing the changes of these spectra. Tumor cells of rat glioma, human glioblastoma and human neuroblastoma were inoculated subcutaneously in the lumbar region of the animals. After the tumor grew to over 1.5 cm in diameter, in vivo 31P-NMR spectrum data was obtained selectively from the tumor with a TMR-32 spectrometer (Oxford Research Systems, U.K.). Several peaks (ATP, inorganic phosphate (Pi), phosphodiesters and phosphomonoesters (PME) were observed in the tumors. The heights of these peaks varied widely corresponding to the tumor growth. However, the spectrum pattern of each tumor in an active stage was found to be essentially the same regardless of histological type or tumor origin. The phosphocreatine (PCr) peak was small, ATP and PME peaks were large and tissue pH calculated from the chemical shift of Pi was low in each tumor group. After intravenous injection of a large dose of a chemotherapeutic agent, ATP peaks decreased and the Pi peak increased gradually, resulting in a dominant Pi peak pattern after several hours in all groups. With lower drug doses, spectrum changes were temporarily seen in the tumors. These findings indicated that drugs with a high dose have a selective and a direct action on the energy metabolism of tumor tissues. In vivo 31P-NMR spectra measurement is very valuable not only to investigate the energy metabolism in tumor tissue but also to evaluate the effects of chemotherapy on the tumor.

Animals↗
PubMed1985

In vivo studies of energy metabolism in experimental cerebral ischemia using topical magnetic resonance. Changes in 31P-nuclear magnetic resonance spectra compared with electroencephalograms and regional cerebral blood flow.

The energy state of the brain during and after transient cerebral ischemia was examined in rats by in vivo measurement of 31P-nuclear magnetic resonance (NMR) spectra using a topical magnetic resonance spectrometer. EEGs and regional CBF (rCBF) were monitored on the same ischemic models. Immediately after the induction of ischemia, the height of the ATP and phosphocreatine peaks in the spectrum began to decrease with a concurrent increase of the inorganic phosphate (Pi) peak. The calculated pH from the chemical shift of Pi decreased during ischemia. The EEG pattern became flat immediately after ischemic induction. The rCBF decreased below the sensitivity level of the measuring instrument. With 30-min ischemia, the 31P-NMR spectrum returned to a normal pattern rapidly after recirculation. However, recovery of the EEG was delayed. The rCBF after recirculation showed postischemic hyperemia followed by hypoperfusion. In cases of 120-min ischemia, none of the spectra showed recovery. Thus, we could investigate the dynamic process of pathophysiological changes occurring in the ischemic brain in vivo.

Animals↗