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Biomedical subjects

S Yoshioka

Publications and source records attributed to S Yoshioka.

At least 181 records · Page 10Linked to original sources
PubMed1993

Changes in carpal tunnel shape during wrist joint motion. MRI evaluation of normal volunteers.

This study evaluated dynamically the morphology of the carpal tunnel during the wrist motion. The object was to determine the transverse dimension (TD), anteroposterior (AP) dimension and cross-sectional area (CA) of the carpal tunnel in the neutral, flexed and extended positions. The wrists of eight male and eight female volunteers aged 20 to 38 years were studied. With wrist extension, AP and CA decreased while the TD increased at the pisiform level, and CA increased at the hamate level. With flexion, TD and CA decreased at the pisiform level and CA decreased at the hamate level. The results showed that the median nerve may be subjected to significant pressure at the pisiform level when the wrist is extended. During wrist flexion, the cross-sectional area decreased at both the level of the pisiform and the hook of the hamate.

Adult↗
PubMed1993

The effect of salts on the stability of beta-galactosidase in aqueous solution, as related to the water mobility.

The effect of salts (KI, KBr, NaCl, KCl, KF, phosphate, and Na2SO4) on the stability of beta-galactosidase in aqueous solution was studied from the aspect of changes in water mobility. At salt concentrations up to 200 mM, the inactivation rate of beta-galactosidase in all the salt solutions studied increased with increasing salt concentration. At higher concentrations, those salts which had little effect on the spin-lattice relaxation time, T1, of water (KI, KBr, and KCl) continued to increase the inactivation rate of beta-galactosidase with increasing concentration, while those salts which decreased the T1 of water (KF, phosphate, and Na2SO4) decreased the inactivation rate. It appeared that the decrease in water mobility caused by KF, phosphate, and Na2SO4 resulted in stabilization of beta-galactosidase. The results indicate that water mobility is an important factor in the denaturation rate of proteins.

Bromides↗
PubMed1993

Stability of beta-galactosidase, a model protein drug, is related to water mobility as measured by 17O nuclear magnetic resonance (NMR).

The inactivation of freeze-dried beta-galactosidase during storage was studied, focusing on the effect of water mobility as measured by the spin-lattice relaxation time, T1, of water using 17O NMR. Inactivation of beta-galactosidase lyophilized from phosphate buffer solution was studied as a function of water content, which in turn affected the T1 of water. An increase in the water content of freeze-dried beta-galactosidase brought about an increase in the T1 of water, as well as a rise in pH. For the freeze-dried enzyme with sufficient water content to be dissolved, the inactivation rate was related to the T1 of water rather than to the pH change. It is suggested that as the water content increases, the mobility of water around the enzyme increases, resulting in enhanced enzyme inactivation. The freeze-dried samples with limited moisture showed inactivation rates faster than those expected from the pH and water mobility, suggesting that the inactivation mechanism is different from that for the freeze-dried enzyme with a larger amount of water. Inactivation of beta-galactosidase in solutions was also studied as a function of phosphate buffer and sodium chloride concentrations, which in turn affected the T1 of water. Because the inactivation rate increased with increasing salt concentrations and the rate extrapolated to zero concentration was negligible, inactivation of the freeze-dried enzyme was apparently induced by the salts used as additives for lyophilization. The enhancing effect of phosphate buffer components, however, was reduced at higher concentrations, an effect related to the decrease in the T1 of water. This result may be ascribed to the decrease in water mobility caused by phosphate buffer components and is consistent with the observation that the inactivation rate of the freeze-dried enzyme with a relatively large amount of water decreased with decreasing T1 of water.

Aspergillus oryzae↗
PubMed1993

Aggregates formed during storage of beta-galactosidase in solution and in the freeze-dried state.

Aggregates formed during storage of freeze-dried beta-galactosidase were compared with those formed in solutions. Freeze-dried beta-galactosidase aggregated during storage in the presence of moisture, producing a protein precipitate which was soluble in guanidine hydrochloride solution but not in buffer solution. The protein precipitate dissolved in guanidine solution exhibited a large molecular size by high-performance size exclusion chromatography and converted to proteins of original size in the presence of dithiothreitol. It is suggested that the aggregation involves chemical interaction via covalent disulfide bonding. In contrast, beta-galactosidase in aqueous solution aggregated without formation of protein precipitates. Soluble aggregates were converted to proteins of original size in guanidine solution without dithiothreitol, suggesting noncovalent bonding. The difference in aggregation behavior may be ascribed to the difference in the water:protein ratio. We propose that inactivation of beta-galactosidase is due to formation of thermally denatured (unfolded) protein, which aggregates dependent on the water:protein ratio, either via noncovalent interactions at a high water:protein ratio in solution or via covalent interaction at a low water:protein ratio in the freeze-dried state.

Buffers↗
PubMed1993

Decreased protein-stabilizing effects of cryoprotectants due to crystallization.

The stabilizing effects of various additives against inactivation of an enzyme (beta-galactosidase from Aspergillus oryzae) during freeze-drying were studied, with a focus on their crystallinity. The crystalline morphology of mannitol and inositol in freeze-dried cakes depended on the solute concentrations before freezing and the freeze-drying method used. The additives in their amorphous state showed concentration-dependent stabilization of the enzyme, whereas additive crystallization during freeze-drying decreased their effects. Heat treatment before freeze-drying also caused crystallization and diminished the stabilizing effects. Noncovalent soluble aggregates were observed in the inactivated enzyme solution. These results show the importance of maintaining the amorphous state of additives used as stabilizing agents during freeze-drying.

Asparaginase↗
PubMed1993

Dissecting aneurysm of the posterior inferior cerebellar artery: case report.

A patient with a dissecting aneurysm of a posterior inferior cerebellar artery who presented with Wallenberg's syndrome is reported. A 31-year-old man suddenly experienced an occipital headache, vertigo, and vomiting, followed by dysphagia. A neurological examination revealed partial Wallenberg's syndrome. Vertebral angiography revealed aneurysmal dilatation at the origin of the left posterior inferior cerebellar artery, with distal luminal narrowing. T1-weighted magnetic resonance imaging demonstrated an area of high-signal intensity, indicating an intramural hemorrhage in the arterial wall of the narrowed lumen. The dissecting aneurysm with a typical intramural hematoma of the posterior inferior cerebellar artery was entrapped with clips after an anastomosis of the left occipital artery to the distal posterior inferior cerebellar artery. The diagnosis and the treatment of dissecting aneurysms of the posterior inferior cerebellar artery are discussed.

Adult↗
PubMed1993

[Urodynamic evaluation for bladder dysfunction after radical hysterectomy].

Bladder dysfunction after radical hysterectomy and/or radiotherapy for uterine cancer is a serious problem. Its pathogenesis has not been well elucidated. Urodynamic and clinical evaluations were performed in 53 patients; 24 of them underwent radical hysterectomy and postoperative radiotherapy (RH + RT), 13 had radical hysterectomy alone (RH), 7 had modified radical hysterectomy (mRH), 9 had radiotherapy alone (RT). Nine preoperative patients without micturition disturbance were examined, serving as controls. Patients with more than 50 ml of residual urine were only 3 in RH + RT, 2 in RH and 1 in RT. Bladder volumes at maximum desire to void were significantly lower in RT than in controls. Intravesical pressures at maximum desire to void were significantly higher in RH + RT and RH than in controls, but there were no significant differences between mRH or RT and controls. Detrusor compliances significantly decreased after radical hysterectomy and/or radiotherapy. Maximum urethral closure pressures significantly decreased after radical hysterectomy with or without radiotherapy. In RH + RT, 18 patients (75%) of them mainly complained of urinary incontinence. Their functional profile lengths were significantly shorter than in controls. We conclude that the pelvic plexus injury by radical hysterectomy compromise both urethral closure function and bladder compliance.

Aged↗
PubMed1992

Purification and properties of Aspergillus niger beta-glucosidase.

Beta-glucosidase was purified from a crude cellulase preparation from Aspergillus niger by affinity chromatography on a methacrylamide-N-methylene-bis-methacrylamide copolymer bearing cellobiamine. The purified enzyme was a dimer with an isoelectric point of 4.0. The molecular mass of the enzyme was estimated to be 240 kDa by gel-permeation chromatography. The enzyme hydrolyzed specifically beta-glucosidic bonds and catalyzed transglucosylation of the beta-glucosyl group of cellobiose to yield 4-O-beta-gentiobiosylglucose in the presence of organic solvents or under neutral conditions.

Aspergillus niger↗
PubMed1992

Effect of water mobility on drug hydrolysis rates in gelatin gels.

The stability of drugs incorporated in gelatin gels was studied, with a focus on the water mobility in the gels. Trichlormethiazide hydrolysis and kanamycin-catalyzed flomoxef hydrolysis in gelatin gels were chosen as models for apparent first-order and second-order hydrolysis, respectively. The mobility of water in gelatin gels was determined by NMR, ESR, and dielectric relaxation spectroscopies. The amount of bound water in the gels was determined from dielectric relaxation spectra. Spin-lattice relaxation time of water determined by 17O NMR and rotational correlation time of an ESR probe determined by an ESR probing method were useful in determining the microviscosity of the gels. The hydrolysis rate of trichlormethiazide in the gels was found to depend on the amount of free water available for the reaction, while that of flomoxef depended on the microviscosity of the gels, which reflected the mobility of water molecules. Thus the dependence of hydrolysis rates on the water mobility was influenced by the hydrolysis mechanism.

Cephalosporins↗
PubMed1992

Differential diagnosis of idiopathic fibrosis from malignant lymphadenopathy with PET and F-18 fluorodeoxyglucose.

Idiopathic fibrosis and malignant lymphoma were studied with positron emission tomography (PET) using 2-deoxy-2-[F-18]fluoro-D-glucose (F-18DG). Cases of retroperitoneal fibrosis and sclerosing peritonitis showed low F-18DG uptake with the mass/muscle radioactivity (M/M) ratio 2.0 and 1.9, respectively. A case of para-aortic adenopathy from malignant lymphoma showed high F-18DG uptake with the M/M ratio 9.4. F-18DG PET study may be useful for the differential diagnosis of idiopathic fibrosis and malignant lymphadenopathy.

Aged↗
PubMed1992

High serum alkaline phosphatase level of meningioma cell origin: case report and review of the literature.

A 13-year-old boy with an anaplastic meningioma at the site of the jugular foramen had an increased serum level of aklaline phosphatase (ALPase) (liver form) in the serum before surgery. Immediately after excision of the tumor, the serum ALPase level decreased dramatically. Histochemical and immunohistochemical examinations revealed ALPase activity (liver form) in the neoplastic cells. This case would be the third with clinical evidence that the increased level of serum ALPase is of neoplastic cell origin from the meningioma. The implications of ALPase in brain tumors are discussed.

Adolescent↗
PubMed1992

Metabolic fate of [14C]triglyceride-entrapped lactosylceramide-bearing liposomes after intravenous injection into mouse.

We investigated the distribution and fate of liposomes after their intravenous injection into a mouse. Liposomes were composed of dimyristoylphosphatidylcholine, cholesterol and dicetylphosphate (7:2:1, molar ratio) with or without lactosylceramide. They were characterized as small unilamellar vesicles, approximately 100 nm in diameter, using gel-exclusion chromatography on a Sephacryl S-1000, freeze-fracture electron microscope and dynamic light scattering method. Liposomes were very stable in serum as seen by the results of leakage of the entrapped marker and electrophoresis experiments. We demonstrated that liposomes were internalized by way of an endocytotic process via coated vesicles detected in the electron microscope. The increase in liver uptake of lactosylceramide-bearing liposomes was mostly accounted for by enhanced uptake in the parenchymal cells, while uptake by non-parenchymal cells was only slightly increased. This observation supported the notion that a galactose-specific receptor was involved in liver uptake of lactosylceramide liposomes. The lactosylceramide-bearing liposomes were preferentially recovered in the liver and were found to first be predominantly localized in the mitochondria-lysosomal fraction. They were then decomposed by lysosomal enzymes, and the hydrolyzed components were reincorporated into membrane phospholipids in the microsomal fraction. At the same time, a rapid and reversible exchange of phosphatidylcholine between microsomes and mitochondria was demonstrated.

Absorption↗
PubMed1992

Effect of radiation therapy against intracranial hemangiopericytoma.

Seven cases of intracranial hemangiopericytoma were studied retrospectively to investigate the efficacy of radiation therapy. Tumor response evaluated by computed tomography and magnetic resonance imaging was obvious after 20-30 Gy irradiation. The total reduction rate was 80-90% and continued as long as 5-7 months after treatment. In five patients receiving radiation therapy before radical removal, the tumors were easily removed without massive hemorrhage. Histological inspection of specimens after irradiation showed a significant disappearance of tumor cells. Pyknosis frequently occurred in endothelial cells, and proliferating vessels with hyalinoid degeneration were also seen. Reticulin fibers between tumor cells were fewer, split, or absent. Preoperative radiation therapy is useful in the treatment of hemangiopericytoma involving considerable surgical risk. Postoperative radiation therapy should be given even if removal is complete.

Adolescent↗
PubMed1992

[Brain metastases from Wilms' tumor without systemic involvement--a case report and review].

A 3-year-old boy presented with multiple brain metastases 21 months after the resection of stage II Wilms' tumor. Metastasis to other organs was not found. He was treated by total removal of a large metastatic tumor in the left temporal lobe and post-operative radiotherapy and chemotherapy. He has been in complete remission for 20 months after surgery. Cerebral metastasis from Wilms' tumor without systemic metastases is very rare. It is speculated that brain metastases occurred in this patient because most of the anticancer agents used in the primary treatment for Wilms' tumor were not able to cross the blood brain barrier.

Antineoplastic Agents↗
PubMed1992

[Urodynamic study on urinary disturbance after therapy of uterine cancer].

It is well known that urinary disturbance often appears after radical hysterectomy for uterine cancer and is aggravated by additional radiation therapy. The aim of this study is to elucidate the pathogenesis and to establish the treatment method of urinary disturbance after therapy for uterine cancer. Forty-five patients with urinary disturbance and ten normal controls were subjected to this study. Changes in clinical symptoms and findings in the Urodynamic study (UDS) in 12 severe cases were investigated before and after treatment with beta 2-stimulant (Mabuterol HCL). Clinical symptoms in cases treated by radiation therapy alone were rare and mild without any pad exchanges, and appeared 5 years after treatment for uterine cancer. Findings of UDS in these cases were mild low compliance of detrusor at maximum desire to void (Cmdv) and mild low bladder volume at maximum desire to void (Vmdv). In cases treated by radical hysterectomy alone, Cmdv decreased immediatelly after the operation and then maximum urethral closure pressure (cPura) gradually decreased. Concerning the cases treated by radical hysterectomy and radiation, severe low Cmdv and severe low Vmdv appeared 5 years after the treatment for uterine cancer in almost all cases, and low cPura appeared immediately after the operation in half of the cases. Treatment with beta 2-stimulant significantly improved urinary frequency, voided volume and urinary incontinence. In UDS findings, Vmdv and Cmdv were significantly improved by the treatment with beta 2-stimulant. The functional profile length and cPura value were not significantly changed. In uroflowmetry, the maximum flow rate and average flow rate were significantly improved by the treatment with beta 2-stimulant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists↗
PubMed1991

Characterization of CS-045, a new oral antidiabetic agent, II. Effects on glycemic control and pancreatic islet structure at a late stage of the diabetic syndrome in C57BL/KsJ-db/db mice.

Antidiabetic effects of CS-045 were evaluated in 5-month-old C57BL/KsJ-db/db mice (db/db). CS-045 administered for 3 weeks to diabetic db/db mice as a 0.2% food admixture improved hyperglycemia (855 +/- 25 v 298 +/- 62 mg/dL, P less than .01) and glucose intolerance, and lowered plasma triglyceride (299.6 +/- 28.7 v 76.3 +/- 20.7 mg/dL, P less than .01) and free fatty acid (FFA) levels (1.16 +/- 0.14 v 0.57 +/- 0.07 mEq/L, P less than .01). Food intake was not changed, while a small but significant increase in body weight was observed in CS-045-treated mice. Plasma insulin levels gradually increased after 5 days of CS-045 treatment, and a nonsignificant increase was observed in plasma insulin levels after 3 weeks (1.85 +/- 0.50 v 4.54 +/- 1.47 mg/mL). In contrast, the plasma glucagon levels decreased after 3 weeks of CS-045 treatment. Histological examination by aldehyde-fucshin staining demonstrated that pancreatic beta cells in CS-045-treated db/db mice were heavily regranulated, whereas most of the beta cells were extensively degranulated in nontreated db/db mice. The heavily regranulated state of beta cells was also compatible with an increase in pancreatic insulin content in CS-045-treated db/db mice. Electron microscopic analysis showed a well-developed endoplasmic reticulum and the accumulation of much amorphous structural material in the intracisternal space of beta cells from CS-045-treated db/db mice, which were suggestive of an increase in insulin synthesis. Moreover, CS-045 treatment decreased exocrine-containing islets, which was associated with the islets' degeneration process. Immunohistochemical staining of islets showed that CS-045 treatment normalized the distribution pattern of endocrine cells in the islets of db/db mice, reflected by a predominantly peripheral location of alpha and delta cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1991

Potential radiopharmaceuticals labeled with titanium-45.

The potential of some compounds labeled with cyclotron-produced titanium-45 (45Ti) as radiopharmaceuticals was studied. Properties of colloid formation of 45TiOCl2 or 45TiO-phytate in vivo resulted in the highest radioactivity uptake in the rat liver, followed by the spleen, suggesting potential for imaging the reticuloendothelial system. Three 45TiO-complexes with diethylenetriaminepentaacetic acid, citric acid and human serum albumin showed the highest radioactivity levels in the blood over 6 h. The binding of the 45Ti with plasma transferrin in vitro and in vivo suggested that these compounds can be used for estimating the blood volume. Also, potential as an indicator representing the breakdown of the blood-brain barrier in the rat was demonstrated by autoradiography.

Animals↗