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Biomedical subjects

K Kuwata

Publications and source records attributed to K Kuwata.

At least 91 records · Page 5Linked to original sources
PubMed1987

The charge effects of the self-diffusion constant of bovine mercaptalbumin.

The charge effect on the translational self-diffusion constant, D, of polyelectrolytes has been quantitatively analyzed based on dynamic light scattering experiments. Perfectly monodisperse bovine mercaptalbumin has been used at low pH as a positively charged polyelectrolyte sample. Completely linear plots of log(g2(t)-1) vs. time t have been obtained for uncharged states of the protein, for the correlation function of the scattered light intensity, g2(t). The plots deviate from linearity as polyions bear the charges. The D values for various ionic states, obtained from the initial slopes of the plots, have been analyzed using the simple theory of Imai and Mandel (N. Imai and M. Mandel, Macromolecules 15 (1982) 1562) derived based on the Onsager-Navier-Stokes equation for solvent flow with counterion distribution around a polyion. It has turned out that the experimental D values coincide well with the theory and that the characteristic nature of D can be elucidated principally from the charge effect.

Diffusion↗
PubMed1987

[A case of double neoplasms--small cell carcinoma in the mediastinum and squamous cell carcinoma of the esophagus].

A 62-year-old Chinese man was admitted to our hospital because of dysphagia and hoarseness. Chest X-rays showed a superior mediastinal mass, and an operation for the removal of this mediastinal tumor was performed. The histological diagnosis indicated a small cell carcinoma, probably arising from the lung. He was readmitted to our clinic one year later with a complaint of dysphagia due to an esophageal cancer. Radical surgery for the esophageal cancer was performed, and the histological findings showed a well differentiated squamous cell carcinoma. The histogenesis of this carcinoma was considered to be independent of the earlier mediastinal tumor.

Adenocarcinoma↗
PubMed1986

Surgical clinicopathologic study of malignant fibrous histiocytoma.

Fifteen men and six women, ranging in age from 20 to 79 years, with malignant fibrous histiocytoma comprised this series. Amputation of the right lower extremity was performed in one patient, wide resection in 7 and marginal excision in 9, respectively. In the other 4 patients, a non-curative resection was carried out. Adjuvant chemotherapy was prescribed post-operatively for 12 patients. Histologic grade of the surgical specimens was Stage I in 3, II in 6, III in 8 and IV in 4. Among fourteen patients living from 10 months to 9 years and 9 months after the operation, the 7 subjected to a wide resection are all disease free. Seven patients died of a local recurrence or a distant metastases. The survival rate of the patients with Stages I, II is significantly higher than those with Stages III, IV. These results show that a wide resection is to be favored and that staging is useful to estimate the prognosis.

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

High-performance liquid chromatographic studies on non-mercapt in equilibrium with mercapt conversion of human serum albumin. II.

High-performance liquid chromatographic (HPLC) analysis of human serum albumin (HSA) on a GS-520 column with 0.03 M sodium phosphate buffer-0.15 M sodium sulphate (pH 6.87) showed three peaks, the principal component corresponding to human mercaptalbumin (HMA) and the secondary and tertiary components to nonmercaptalbumin (HNA). Using HPLC analysis, the nonmercapt----mercapt conversion of HSA during haemodialysis and the mercapt----nonmercapt conversion after haemodialysis in chronic renal failure were re-confirmed, indicating that HMA is a covalent carrier protein for sulphur-containing amino acids. Fractions of HMA in various liver diseases were significantly lower than those of healthy male adults.

Adult↗
PubMed1985

Ion-exchange high-performance liquid chromatographic studies on sulphydryl-catalysed structural alterations of bovine mercaptalbumin.

The N-A isomerization (the intramolecular SH/S-S exchange reaction) of bovine mercaptalbumin (BMA) in alkaline medium was studied by using ion-exchange high-performance liquid chromatography (HPLC) and moving-boundary electrophoresis. Results obtained by ion-exchange HPLC on the N-A isomerization of BMA were consistent with those by moving-boundary electrophoresis and showed at least two kinds of the A-form, A1 and A2, indicating that the N-A isomerization is a multi-step reaction. The rate of the N-A isomerization was strongly suppressed in [2H]water solution. The suppression by [2H]water might support the current view that intra- and intermolecular hydrophobic and/or hydrogen bonds are strengthened in [2H]water.

Animals↗
PubMed1985

Electron spin relaxation of synthetic melanin and melanin-containing human tissues as studied by electron spin echo and electron spin resonance.

Electron spin lattice relaxation times (T1) and the phase memory times (Tm) were obtained for the synthetic melanin system from 3-hydroxytyrosine (dopa) by means of electron spin echo spectroscopy at 77 degrees K. Saturation behavior of the ESR spectra of melanins in melanin-containing tissue and of the synthetic melanin was also determined at the same temperature. The spin lattice relaxation time and the spectral diffusion time of the synthetic melanin are very long (4.3 ms and 101 microseconds, respectively, in the solid state), and the ESR signal saturates readily at low microwave powers. On the other hand, ESR spectra of natural melanins from the tissues chosen for this study, as well as those of synthetic melanins which contain Fe3+ of g = 4.3 and Mn2+ of g = 2, are relatively difficult to saturate compared with samples without such metal ions. These results show clearly that a large part of those two metal ions in sites responsible for the ESR spectral components with these particular g values are coordinated to melanin in melanin-containing tissue, and modify the magnetic relaxation behavior of the melanin. Accumulations of these metal ions in melanins are different from system to system, and they increase in the order: hair (black), retina and choroid (brown), malignant melanoma of eye and skin, and lentigo and nevus of skin.

Copper↗
PubMed1985

Qualitative and quantitative analysis of muscarinic acetylcholine receptors in the piebald lethal mouse model of Hirschsprung's disease.

Cholinergic innervation in the aganglionic bowel of the piebald lethal mouse model of Hirschsprung's disease was investigated by analysis of muscarinic acetylcholine receptors before and after administration of hexamethonium. After hexamethonium administration in the normal rectum, the maximum specific binding (Bmax) of [3H]quinuclidinyl benzilate increased from 196.6 to 346.2 fmol/mg protein without affecting the dissociation constant. This increase of muscarinic acetylcholine receptors was associated with a decrease in the 50% effective dose (ED50) of contractile response to oxotremorine from 3.8 X 10(-7) M to 6.5 X 10(-8) M. In the aganglionic rectum, hexamethonium administration did not change the Bmax (166.4 fmol/mg protein) or dissociation constant value. The ED50 of contractile response to acetylcholine and oxotremorine (4.3 X 10(-8) M, 6.5 X 10(-8) M) was lower than that in the normal rectum (1.9 X 10(-7) M, 2.0 X 10(-7) M), but it was not changed by hexamethonium. It is concluded that cholinergic innervation is congenitally absent in the aganglionic rectum in piebald lethal mice.

Acetylcholine↗
PubMed1985

HPLC-studies on nonmercapt-mercapt conversion of human serum albumin.

Human mercaptalbumin (HMA) and nonmercaptalbumin (HNA) could be separated by high-performance liquid chromatography (HPLC) at neutral pH. Using HPLC, the present authors found the nonmercapt-mercapt conversion (HNA----HMA) during hemodialysis and the mercapt-nonmercapt conversion (HMA----HNA) after hemodialysis in chronic renal failure, indicating HMA as the covalent carrier protein for sulfur-containing amino acids.

Chromatography, High Pressure Liquid↗
PubMed1985

Circular dichroic and fluorometric studies on the acid-induced isomerization of bovine plasma albumin--1 -anilino-8-naphthalenesulfonate complex.

The acid-induced isomerization (the N-F transition) and expansion of bovine plasma albumin--1-anilino-8-naphthalenesulfonate complex, BPA-ANS1.0 complex (molar ratio of added ANS to BPA = 1.0) were studied by measuring fluorescence and induced CD spectra of ANS. Decrease in the reciprocal of fluorescence polarization, increase in fluorescence intensity and blue shift of fluorescence of ANS in BPA-ANS1.0 complex were correlated with the initial part of the N-F transition and/or the N-F1 transition. Induced CD spectra of ANS showed positive bands at 250-258 and 320-350 nm and one negative band at 280 nm. Most of changes (decreases) in -[theta]280 were also correlated with the initial part of the N-F transition and/or the N-F1 transition. Changes in fluorescence parameters and induced CD spectra of ANS (-[theta]280) might indicate the conformational changes around a strong ANS binding site in the N-terminal domain (Reed et al. (1975), Jonas & Weber (1970) and Brown & Shockley (1982].

Anilino Naphthalenesulfonates↗
PubMed1984

Endoscopic extraction of foreign bodies from the duodenum: four cases in infancy.

Four cases of foreign bodies in the duodenum were treated using a flexible fibre-optic panendoscope. All the patients were boys and eight months to four years of age. The ingested foreign materials were an injection needle, a marking pin, a hairpin and a curtain hook. Endoscopic extraction was attempted, because the ingested objects might cause perforation or obstruction of the gastrointestinal tract. Until recently, they had to be carefully watched or prophylactic operation suggested. Under general anaesthesia, duodenal endoscopy was easily performed and extraction of foreign bodies was not found to be difficult during infancy. This is considered to be a safer and less hazardous way than careful watching or prophylactic operation.

Child, Preschool↗
PubMed1984

A multiple regression equation for prediction of posthepatectomy liver failure.

This article reports a multiple regression equation for prediction of posthepatectomy liver failure. In phase I, using the correlations between 17 preoperative parameters (Xi) and the postoperative course scored (Y) of the past 36 hepatectomized patients, we proposed the following multiple regression equation: Y = -110 + 0.942 X resection rate (%) + 1.36 X ICG retention rate (%) + 1.17 X patient's age + 5.94 X ICG maximal removal rate (mg/kg/min). With the equation, the calculated Y value (prediction score) of these patients revealed that prediction scores of the eight nonsurvivors with liver failure were more than 50 points while those of the 28 survivors were 50 points or less. In phase II, the relationships between early prognosis and a precalculated prediction score were prospectively found the same as that seen in phase I. These findings indicate that our formula is a useful prognostic index for prediction of posthepatectomy liver failure.

Adult↗
PubMed1984

Prediction of the safe limits of hepatectomy by combined volumetric and functional measurements in patients with impaired hepatic function.

By use of computed tomography measurements, preoperative estimations of the safe limits of hepatic resection have been attempted in 38 patients with primary hepatocellular carcinoma who underwent hepatectomies of varying degrees. Twenty eight (73.7%) of these 38 patients had cirrhosis. Preoperative computed tomography estimations of volume of liver and hepatocellular carcinoma have been compared with measured volume of the resected specimens. The average differences between the estimated and actual volumes of resected liver and hepatocellular carcinoma were within 10% and 7%, respectively. To quantify the extent of hepatectomy, the "parenchymal hepatic resection rate" (formula: see text) was provided. As an indicator of functional impairment of the liver, the retention rate 15 minutes after an intravenous injection of indocyanine green dye (ICG) at 0.5 mg/kg (ICG R15) was used. A close correlation was observed between the parenchymal hepatic resection rate and ICG R15 relative to the patients' outcome, indicating their potential use in the prediction of the safe limits of hepatectomy and the probable development of posthepatectomy liver failure.

Carcinoma, Hepatocellular↗
PubMed1983

Increase in muscarinic acetylcholine receptors in mouse intestine by hexamethonium treatment.

The effects of hexamethonium (C6) administration on muscarinic acetylcholine receptors (mACh-R) in the intestine and brain of mice were investigated. Mice were treated with C6 with an osmotic mini-pump (330 mg/kg/day) for one week and then the binding of 3H-quinuclidinylbenzilate (3H-QNB) in the intestine and brain were assayed. This treatment increased the maximum specific binding (Bmax) of 3H-QNB from 160 to 320 fmoles/mg protein in the ileum and from 190 to 340 fmoles/mg protein in the rectum, without affecting the KD values in these regions. On the contrary, C6 treatment did not change the Bmax or KD value in brain tissues. This C6 treatment increased the sensitivity of the contractile response of the intestine to muscarinic agonists, possibly by increasing mACh-R.

Animals↗
PubMed1983

Simultaneous radical surgical treatment for membranous obstruction of the inferior vena cava and the coincident hepatocellular carcinoma--the first successful case.

To our knowledge, this is the first report of a patient for whom a successful radical treatment for both membranous obstruction of the inferior vena cava (MOVC) and coincident hepatocellular carcinoma (HCC) were simultaneously carried out. A 36 year old Japanese man with Budd-Chiari syndrome due to MOVC was found to have HCC in the right hepatic lobe during a shunt operation between the inferior vena cava (IVC) and the right atrium (RA), using a vascular prosthetic graft. He was referred to us from another institute for further operative procedures. Both the mediastinum and the abdomen were entered through a long midline incision with longitudinal splitting of the sternum. The graft that had been occluded by thrombus was removed. Transcardiac membranotomy was achieved by manual manipulation and then by Tubb's dilator. The hepatic tumor with an abundant surgical margin of the liver was resected. The tumor of 2.5 X 2.5 X 2.0 cm was a well differentiated clear cell type HCC associated with congestive liver cirrhosis. Postoperative contrast and pressure studies through IVC showed satisfactory results. Serum alfa-fetoprotein levels decreased from 503 to 12 ng/ml. The patient is well at least for 44 months after the surgery without any recurrence at the time of completion of this writing.

Adult↗
PubMed1983

Serum and erythrocyte acetylcholine esterase in Hirschsprung's disease.

Determination of acetylcholine esterase in serum (S-AChE) and erythrocytes (E-AChE) was carried out in nine patients with Hirschsprung's disease and 16 normal controls. S-AChE was significantly elevated in patients with Hirschsprung's disease, while no significant difference was observed in E-AChE in these two groups. In 17 patients with Hirschsprung's disease, S-AChE and E-AChE were determined after definitive operation. Twelve of these patients underwent a Duhamel type procedure in which a small part of the aganglionic bowel segment remained unresected. Five patients were treated by Swenson's procedure performing complete resection of the aganglionic bowel segment. S-AChE in patients treated by the Duhamel type procedure remained elevated, while it was as low as that in normal controls in patients who underwent Swenson's procedure. There was no significance in E-AChE in both groups. This study suggests a close relation of the level of S-AChE to the extent of the aganglionic bowel segment in Hirschsprung's disease.

Acetylcholinesterase↗