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Biomedical subjects

F Kato

Publications and source records attributed to F Kato.

At least 73 records · Page 4Linked to original sources
PubMed1995

Purification and properties of two chitinases from Streptomyces sp. J-13-3.

Two chitinases (Chi-A and Chi-B) purified from Streptomyces sp. J-13-3 had the same molecular weights (31,000) and enzymatic properties (optimum pH and temperature of pH 6.0 and 45 degrees C) but had significantly different isoelectric points (3.9 for Chi-A, 3.5 for Chi-B). Chi-A and -B had identical N-terminal amino acid sequences (ADXAAAWNASSVYTGGGSASYNGHN), similar amino acid compositions, and immunological cross-reactivities. A concomitant decrease of Chi-A and increase of Chi-B was observed in their productions during cultivation.

Amino Acid Sequence↗
PubMed1995

Molecular forms of human brain natriuretic peptide (BNP) in plasma of patients on hemodialysis (HD).

Plasma brain natriuretic peptide (BNP) levels have been reported to increase in patients with heart failure and end-stage renal disease (ESRD); however, little is known about molecular forms of plasma BNP that increase in these diseases. In the present study, we analyzed the molecular forms of plasma BNP in ESRD patients of both before (pre-) and after (post-) hemodialysis (HD) state. The plasma extract was analyzed by gel filtration on a TSK-GEL G2000 SW column followed by a RIA for both BNP and atrial natriuretic peptide (ANP). In the pre-HD patients, a 14- to 2300-fold increase in plasma level of immunoreactive (ir-) BNP was observed when compared to normal controls. A ratio of BNP-32 to g-BNP (pro BNP) in plasma from the patients was much larger than that in plasma from normal subjects, indicating that the high plasma level of ir-BNP level in the patients on HD largely results from a marked increase in BNP-32. HD significantly (P < 0.01) lowered the plasma levels of both BNP-32 and g-BNP with a greater reduction in BNP-32 than in g-BNP. Whereas, a-ANP was a main molecular form of plasma ANP in both pre- and post-HD plasma. These results suggest that plasma BNP-32 plays an important role in the sodium-fluid balance and that secretion and metabolism of BNP may differ from those of ANP in the HD patients.

Adult↗
PubMed1995

Effects of chondroitinase ABC on degenerative intervertebral discs.

The effects of chondroitinase ABC on surgically induced degenerative rabbit intervertebral discs were determined during a 12-week period by magnetic resonance imaging, radiography, and histologic examination. Rabbit intervertebral discs were surgically extruded, inducing disc degeneration 12 weeks before injection of chondroitinase ABC. Magnetic resonance imaging showed a hypointense area in the center of the surgically induced disc degeneration. After injection of chondroitinase ABC, the hypointense area became more intense, but reversed somewhat by the end of the 12-week period. Additional evidence of the effects of chondroitinase ABC on a surgically induced degenerative disc model was shown by radiographic evidence of shrinkage of the disc after injection. Histologic examination revealed a fibrous degenerative disc induced by surgical extrusion. However, the staining properties of the matrix of the nucleus pulposus was similar to that of normal discs before chondroitinase ABC injection, but diminished after the injection, with slight recovery at 12 weeks. The results suggest that chondroitinase ABC induces chemonucleolysis in the degenerated disc. Also, chondroitinase ABC does not destroy the degenerative disc matrix ability to regenerate after 12 weeks.

Animals↗
PubMed1994

Improved method for mutagenicity testing of gaseous compounds by using a gas sampling bag.

A simple and safety gas exposure method was developed using a gas sampling bag as an exposure vessel and a preparation vessel of diluted gas. The gas exposure conditions such as amount of S9 in the plate, volume of gas for the plate, amount of top agar, exposure period and exposure temperature were examined by mutagenicity testing of 1,3-butadiene using the gas sampling bag. Mutagenicity tests of 14 compounds and 1,3-butadiene on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA were also examined by the developed gas exposure method. 1,3-Butadiene, propyne (methyl acetylene), monochlorodifluoromethane, ethylchloride, diborane and silane were mutagenic. 1-Butene, 2-butene, 2-methylpropene, methyl vinyl ether, trichlorofluoromethane, dichlorodifluoromethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, 1,1-difluoroethane and phosphine were not mutagenic on S. typhimurium TA98, TA100, TA1535 and TA1537, and E. coli WP2 uvrA with or without metabolic activation. These results were compatible with a previous report, and this developed method has the advantage that it can be tested easily and safely for combustible and self-combustible substances such as 1,3-butadiene and silane.

Animals↗
PubMed1994

Intraoperative ultrasonographic evaluation of the spinal cord in cervical myelopathy.

Intraoperative spinal ultrasonography (IOSS) was used to evaluate and monitor the spinal cord in 49 patients with cervical myelopathy. Intraoperative spinal ultrasonography demonstrated movements of the dura mater and the spinal cord at the cardiac rate, with some variability in intensity and mode. It also delineated the anterior surface of the spinal canal and configuration of the spinal cord. Statistical analysis showed no correlation between clinical outcome and morphologic restoration, and between clinical outcome and variations in intensity or mode of the pulsatile spinal cord movements. Spinal cord motions were surmised to be generated not only by the anterior spinal artery, but also by other factors. Dural pulsations clearly did not always imply the absence of compression of the spinal cord. Intraoperative spinal ultrasonography was thus quite useful for monitoring decompression in cervical myelopathy.

Adult↗
PubMed1994

Preschool sarcoidosis manifesting as juvenile rheumatoid arthritis: a case report and a review of the literature of Japanese cases.

Nine Japanese cases of sarcoidosis in children of 4 years of age or younger have been reported in the literature, including the case presented here. Clinically, preschool sarcoidosis is distinctly different from that of older children; it is characterized by a triad of skin, joint and eye lesions without pulmonary involvement. It is easily confused with juvenile rheumatoid arthritis which also presents the symptoms of arthritis and uveitis. We report on a patient with preschool sarcoidosis who was initially diagnosed as having juvenile rheumatoid arthritis. We recommend prompt skin biopsy to differentiate between these conditions.

Arthritis, Juvenile↗
PubMed1994

Anti-inflammatory and immunosuppressive effects of 1,6-anhydro-3,4-dideoxy-2-furfuryl-beta-D-threo-3-enopyranose (MT2221), a novel anhydro-enopyranose derivative, on experimental animal models.

The anti-inflammatory effects of 1,6-anhydro-3,4-dideoxy-2-furfuryl-beta-D-threo-3-enopyranose (MT2221) were investigated using animal models and compared with the effects of dexamethasone (DEX) and cyclosporin A (CYA). MT2221 inhibited carrageenan-induced acute inflammation and adjuvant arthritis in rats, as well as the delayed-type hypersensitive response and collagen-induced arthritis (CIA) in mice. However, it seemed that this compound was more effective against murine CIA than upon the other inflammation models. The MT2221 mode of action differed from those of conventional non-steroidal anti-inflammatory drugs (NSAIDs) and disease modifying anti-rheumatic drugs (DMARDs). All of these drugs are effective against acute inflammation or adjuvant arthritis models, but not against murine CIA. DEX and CYA did inhibit murine CIA, but in other animal models, their mode of action differed from that of MT2221. Moreover, allograft transplantation in mice showed that MT2221 slightly prolonged the allograft survival time. These results suggest that MT2221 has not only anti-inflammatory but also immunosuppressive effects based upon a novel mechanism of action that is different from NSAIDs, DMARDs, DEX and CYA.

Animals↗
PubMed1993

The increased signal intensity at the vertebral body endplates after chemonucleolysis demonstrated by magnetic resonance imaging.

Changes in signal intensity observed by magnetic resonance imaging in the contiguous end plates of injected discs after chemonucleolysis over a period of 2 years in 28 patients were evaluated. These changes appeared to be of two types; a transiently increased signal intensity on T2-weighted images, and a progressively increased signal intensity on T1-weighted images with isointense or hyperintense signal on T2-weighted images. The former appeared within three months and disappeared within 2 years. This change was observed in six patients (21%), whose mean age was higher than that of the other patients. This change correlated with the preinjection state of the affected disc. The latter appeared after 2 years and was accompanied by sclerotic changes on roentgenograms. These changes were observed in five patients (18%). The discs, of which the contiguous end plates showed these changes, did not recover the decreased nuclear signal intensity in four patients. These changes are considered to be a sign of degenerative spondylosis in the treated segment.

Adult↗
PubMed1993

New transducers for intraoperative spinal sonography. Technical note.

Although ultrasonography during spinal cord surgery has been widely accepted, it still has limitations in clinical application because of the size of the transducers needed and the immersion method. The authors report on newly designed microprobe transducers used to evaluate intramedullary spinal cord lesions and to monitor surgical procedures. This microprobe system permitted the microscopic use of intraoperative ultrasonography without requiring saline immersion.

Female↗
PubMed1993

[A case of intrathoracic dumb-bell ganglioneuroma and a surgical approach using spinal evoked potentials (SEP)].

A successfully treated case of a seven-year-old girl with a left intrathoracic Dumb-bell ganglioneuroma is reported. The tumor was 10 cm in diameter. Preoperative angiography revealed that the location of tumor was very close to the Adamkiewicz artery. In order to prevent the artery from damaging, spinal evoked potentials (SEP) was used during the surgery and was very useful for monitoring the spinal cord. Although SEP has often been employed in spine surgery, the literature on the use of it for posterior mediastinal tumor is scarce. It is considered that SEP is very useful for not damaging the feeding artery to the spinal cord, and for preventing the postoperative neurologic complications.

Child↗
PubMed1993

Administration and dosage of iohexol, a nonionic contrast medium, for dynamic renal computed tomography.

We investigated the optimal method of administering iohexol, which contains 300 mg iodine/ml (Omnipaque 300), a nonionic contrast medium, to maintain adequate renal contrast while reducing artifacts during dynamic CT scanning. In this study, 76 patients with renal disease received 10-50 ml of iohexol as follows: group I (14 patients), 20 ml injected as an intravenous bolus for 5 sec, followed by 30 ml intravenous drip infusion for 5 min; group II (18 patients), bolus of 20 ml injected for 5 sec; group III (13 patients), 20 ml diluted with sterile water (total volume 40 ml), and injected as a bolus for 8 sec; group IV (15 patients), 20 ml injection for 5 sec followed by intravenous drip infusion of 200 ml of Hartmann-Ringer's solution given at maximum speed; and group V (14 patients), 10 ml diluted with sterile water (total volume 20 ml) injected as a bolus for 5 sec. We found that corticomedullary differentiation was most distinct on the images obtained from group IV. We concluded that a lower concentration of iohexol (150 mg iodine/ml) given by intravenous fluid loading can provide superior CT images.

Adult↗
PubMed1993

Comparison of tissue reaction with chondroitinase ABC and chymopapain in rabbits as the basis of clinical application in chemonucleolysis.

Although chemonucleolysis with chymopapain is an approved treatment for lumbar intervertebral disk herniation, recent serious complications have raised doubt concerning its safety. It is therefore necessary to search for a safer and more selective agent than chymopapain for chemonucleolysis. Experimental chemonucleolysis with chondroitinase ABC was thus tested and compared with chymopapain. Acute tissue reactions to chondroitinase ABC were investigated and compared with chymopapain. The epidural space, yellow ligament, sciatic nerve, knee joint, and Achilles tendon were examined. Chymopapain damaged nervous and ligamentous tissues as well as cartilaginous tissue. Chondroitinase ABC did not damage nervous and ligamentous tissue. Chondroitinase ABC affected only cartilaginous tissue, and its action was chiefly limited to digestion of the matrix. Chondroitinase ABC has high enzymatic specificity for matrix in vivo. In addition, chondroitinase ABC is less toxic to noncartilaginous tissues than chymopapain. Chondroitinase ABC might be a more suitable and safer enzyme than chymopapain for chemonucleolysis.

Achilles Tendon↗
PubMed1992

Changes seen on magnetic resonance imaging in the intervertebral disc space after chemonucleolysis: a hypothesis concerning regeneration of the disc after chemonucleolysis.

Measurements of the intervertebral disc space were made by magnetic resonance imaging and plain film examinations over a period of 2 years in 26 patients who had undergone chemonucleolysis. The height of the posterior portion of the disc decreased after 3 months and never recovered; the height of the anterior portion also decreased but recovered slightly over the same period. The angle of lordosis and the range of motion in the treated segment were decreased, but recovered. Marked decrease in signal from the disc was observed after 2 weeks which did not recover till 2 years after chemonucleolysis. We suspect that the disc degenerated markedly after chemonucleolysis and changed into a type of scar tissue, maturation of which could stabilize the affected segment.

Adolescent↗
PubMed1992

Intraoperative sonography of intramedullary spinal cord tumours.

Intraoperative spinal sonography was performed 23 times in 20 patients with intramedullary spinal cord tumours, and the sonographic features were examined. Eight cases of astrocytoma were classified into three types: type 1, seen in 3 children, had intramedullary, circular or oval, hyperechogenic multiple tumour shadows; type 2 presented inter-multimyelomere, relatively well-defined single tumour shadows corresponding to grade III and I for two juvenile and aged cases each, respectively; and type 3 appeared ill-defined and diffusely infiltrating. The relationships between these types, the ages of patients and histological grades were considered a potential clue to mechanisms of occurrence and infiltration of astrocytoma. All 7 ependymomas had syrinxes, of three types; central canal was very large, the tumour lying within it like an island; or the tumour was in contact with a cephalocaudal side part of the syrinx; or the tumour had a syrinx or cyst. Sonographic images thus differ according to the tumour, but differential diagnosis is currently limited. Development of sonographic equipment, with upgrading its resolving power are hoped for.

Adolescent↗
PubMed1992

Intraoperative ultrasonography of extramedullary spinal tumours.

Intraoperative spinal sonography (IOSS) was performed in 28 patients with extramedullary spinal tumours. Images were obtained of 31 tumours, because 2 patients had multiple tumours. There were 17 neurilemmomas, 9 meningiomas and 2 dermoid cysts. All tumours appeared well-defined and highly echogenic. There was no difficulty differentiating extramedullary spinal tumours from intramedullary masses excepting case, a big neurilemmoma at the conus medullaris. All images were assessed with reference to the surface of the lesions, the existence of cysts, and movement. Neurilemmomas had smooth surfaces, some cysts, and exhibited a "floating" movement. Meningiomas had irregular surfaces, were more highly echogenic than neurilemmomas, and adhered tightly to the dura mater. However, some neurilemmomas and meningiomas did not have these, and it was not always possible to differentiate them. Although IOSS has limitations of resolution, it gave useful information about the size of the tumours, the degree of displacement of the spinal cord, and even about the type of tumour in some cases. It was extremely helpful to the surgeon.

Adult↗
PubMed1992

Serial changes observed by magnetic resonance imaging in the intervertebral disc after chemonucleolysis. A consideration of the mechanism of chemonucleolysis.

Changes in the intervertebral disc after chemonucleolysis in 26 patients were observed by magnetic resonance imaging for 1 year, and from the results a mechanism for chemonucleolysis was considered. A reduction in size of the herniation was not recognized 2 weeks after treatment, when chymopapain had caused necrosis of the disc, but began after 4 weeks, when regeneration of the disc had occurred. The herniation was further reduced after 3 months, and the disc had become fibrocartilaginous in a cicatricial process. Marked decrease in disc signal was observed after 2 weeks, and never recovered. From these facts, it is considered that chymopapain might never cause primary diminution of disc herniation, and any reduction of herniation that occurs is due to the effects of a secondary cicatricial contraction.

Adolescent↗
PubMed1992

Purification and properties of mycodextranase from Streptomyces sp. J-13-3.

An enzyme hydrolyzing nigeran (alternating alpha-1,3- and alpha-1,4-linked glucan) was purified from the culture filtrate of Streptomyces sp. J-13-3, which lysed the cell wall of Aspergillus niger, by percipitation with ammonium sulfate and column chromatographies on DEAE-Sephadex A-50, CM-Sephadex C-50, chromatofocusing, and Sephadex G-100. The final preparation was homogenous in polyacrylamide gel electrophoresis (PAGE). The molecular weight of the enzyme was 68,000 by SDS-PAGE and gel filtration. The optimum pH and temperature for the enzyme activity were 6.0 and 50 degrees C, respectively. The enzyme was stable in the pH range from 6.0 to 8.0 and up to 50 degrees C. The enzyme activity was inhibited significantly by Hg+, Hg2+, and p-chloromercuribenzoic acid. The Km (mg/ml) for nigeran was 3.33. The enzyme specifically hydrolyzed nigeran into nigerose and nigeran tetrasaccharide by an endo-type of action, indicating it to be a mycodextranase (EC 3.2.1.61) that splits only the alpha-1,4-glucosidic linkages in nigeran.

Carbohydrate Sequence↗