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Biomedical subjects

S Katoh

Publications and source records attributed to S Katoh.

At least 163 records · Page 9Linked to original sources
PubMed1995

Monoclonal antibodies to CD44 and their influence on hyaluronan recognition.

Antibodies to CD44 have been used to inhibit a variety of processes which include lymphohemopoiesis, lymphocyte migration, and tumor metastasis. Some, but not all, CD44-mediated functions derive from its ability to serve as a receptor for hyaluronan (HA). However, sites on CD44 that interact with either ligands or antibodies are poorly understood. Interspecies rat/mouse CD44 chimeras were used to analyze the specificity of 25 mAbs and to determine that they recognize at least seven epitopes. Amino acid substitutions that resulted in loss of antibody recognition were all located in the region of homology to other cartilage link family proteins. While at least five epitopes were eliminated by single amino acid replacements, multiple residues had to be changed to destroy binding by other antibodies. One antibody was sensitive to changes in any of three separate parts of the molecule and some antibodies to distinct epitopes cross-blocked each other. Certain antibodies had the ability to increase HA binding by lymphocytes but this did not correlate absolutely with antibody specificity and was only partially attributable to CD44 cross-linking. Antibodies that consistently blocked HA recognition were all sensitive to amino acid changes within a short stretch of CD44. Such blocking antibodies interacted with CD44 more strongly than ligand in competition experiments. One large group of antibodies blocked ligand binding, but only with a particular cell line. This detailed analysis adds to our understanding of functional domains within CD44 and requirements for antibodies to influence recognition of one ligand.

Amino Acid Sequence↗
PubMed1995

Pulmonary arteriovenous fistula associated with unequal branching of the pulmonary artery system.

A 60-year-old woman was admitted to our hospital with shortness of breath and was diagnosed to have pulmonary arteriovenous fistula with unequal branching of the pulmonary artery system, as assessed by pulmonary angiography. The concomitant occurrence has not been reported previously. Although the etiology of these abnormalities is unknown, these abnormalities are considered to have occurred during an early stage of fetal development. The analysis of a concomitant occurrence of these abnormalities may be useful in elucidating the etiology of pulmonary arteriovenous fistula.

Arteriovenous Fistula↗
PubMed1995

Cranioplasty with split-thickness calvarial bone.

Cranioplasty with autogenous split-thickness calvarial bone was performed in 10 patients. Follow-up for a mean of 19 months (range 2-43 mos) showed satisfactory protection of the brain and cosmetic reconstruction. No serious complication was seen except in one patient with postoperative epidural abscess. Split-thickness calvarial bone graft is recommended in patients with previous infection or high risk of infection, in poorly vascularized recipient sites resulting from multiple operations or irradiation, and in younger patients aged more than 7 years.

Adolescent↗
PubMed1995

FK506 treatment of graft-versus-host disease developing or exacerbating during prophylaxis and therapy with cyclosporin and/or other immunosuppressants. Japanese FK506 BMT Study Group.

A phase II study of the efficacy and safety of FK506, a new potent immunosuppressant, has been conducted in 49 patients with GVHD after allogeneic BMT. Eighteen patients with acute GVHD and 31 with chronic GVHD entered the study. FK506 was administered at an initial dose of 0.05 mg/kg i.v. or 0.15 mg/kg orally twice a day to those whose GVHD had become uncontrollable with cyclosporin and/or other immunosuppressants. The response to FK506 was evaluated in 13 patients with acute and 26 with chronic GVHD. A marked response was observed in 5 and a good response in 2 of 13 patients with acute GVHD. For those with chronic GVHD, the response was marked in 2 patients, good in 10 and poor in 8. The most common adverse effects were renal toxicity (53.1%), followed by nausea and vomiting (30.6%) and a feeding of warmth (18.4%). There was a correlation between renal toxicity and whole blood levels of FK506. The dose should be adjusted to keep a trough level between 15 and 25 ng/ml. FK506 is promising in the treatment of both acute and chronic GVHD, even if it is intractable with other immunosuppressants, and may be most effective if administered early in the course of GVHD.

Acute Disease↗
PubMed1995

Lesions of the lumbar posterior end plate in children and adolescents. An MRI study.

We have reviewed 37 patients under the age of 18 years with lesions of the lumbar posterior end plate. All but one were active in sport, and most were seen because of low back pain. An abnormality was commonly found at the inferior rim of the body of L4 and at the superior rim of the sacrum. All adjacent intervertebral discs showed a decrease of signal intensity on the T2-weighted MRI. In 12 patients there was no interposed tissue at the posterior end-plate lesions. When disc material had migrated posteriorly none protruded beyond the posterior margin of the end plate, the dissociated portion of which was the main element compressing neural tissue. The posterior end-plate lesion should be regarded as a vertebral non-articular osteochondrosis.

Adolescent↗
PubMed1995

Lumbar spondylolysis in children and adolescents.

We investigated 185 adolescents under the age of 19 years with spondylolysis. All but five were active in sport. The pars defect was classified into early, progressive and terminal stages. Of the 346 pars defects in 185 patients, 39.6% were early, 29.5% progressive and 30.9% in the terminal stages. Conservative management produced healing in 73.0% of the early, 38.5% of the progressive and none of the terminal defects. These results suggest that spondylolysis is caused by repetitive microtrauma during growth and can be successfully treated conservatively if treatment is started in the early stage. There was elongation of the pars interarticularis as the pars defect progressed, and this is likely to be a consequence of the defect rather than a contributing cause.

Adolescent↗
PubMed1995

[Perioperative management of patients with Meigs syndrome].

We report our perioperative management of three cases of Meigs syndrome. The major pre-operative problems in Meigs syndrome are physical trouble caused by giant mass in peritoneal space, respiratory distress, and poor nutrition. These problems must be settled before the operation. The important points in the pre-operative management are 1) respiratory care employing the intermittent positive pressure breathing (IPPB) and the pleural effusion drainage, and 2) the correction of intravascular volume and the concentration of albumin and hemoglobin by transfusion of massive lactated Ringer solution and albumin solution and/or whole blood when they are necessary. During the operation, the epidural anesthesia under spontaneous breathing is the best method of anesthesia. According to circumstances, we adopt the intra-tracheal intubation with continuous positive airway pressure breathing (CPAP). We can generally deal with excessive bleeding by transfusion of lactated Ringer solution and plasma expander, during the first half of operation. By the end of the operation, however, the correction of the concentration of albumin and hemoglobin must be made by the fresh frozen plasma and blood transfusion. After the operation, we use epidural analgesia to control the postoperative pain. We have succeeded in the treatment of three cases of Meigs syndrome owing to our perioperative management as described above.

Analgesia, Epidural↗
PubMed1995

The efficacy of indomethacin in the treatment of uremic pericarditis.

Uremic pericarditis is common in patients undergoing chronic hemodialysis and has been difficult to cure using conservative medical and surgical methods of treatment. Indomethacin therapy for uremic pericarditis has been reported infrequently. We present a case of uremic pericarditis in which indomethacin was particularly effective. The patient was a 45-year-old woman with thrombocytopenia due to Banti's syndrome and congestive heart failure with pericardial effusion. She had been undergoing hemodialysis for 3 years for chronic renal failure due to chronic glomerulonephritis. Uremic pericarditis was diagnosed based on serological laboratory results, aspirated pericardial fluid, and an echocardiogram. She was treated with oral doses of 25 mg t.i.d. indomethacin in addition to hemodialysis and extracorporeal ultrafiltration method. Pericardial effusion and left ventricular dysfunction disappeared after indomethacin therapy for 38 days. There are conflicting reports on the efficacy of indomethacin therapy in patients with uremic pericarditis. While indomethacin therapy was very effective in our case, there may be many causes of uremic pericarditis for which indomethacin may not be efficacious. Further investigations of indomethacin therapy for patients with uremic pericarditis are necessary to elucidate the therapeutic mechanism by which indomethacin acts.

Administration, Oral↗
PubMed1995

[A case of hypertensive hypertrophy in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were observed after antihypertensive therapy].

A case of hypertensive hypertrophy is described in which both regression of hypertrophy and improvement of the abnormalities in iodine-123-metaiodobenzylguanidine (MIBG) myocardial imagings were seen after 7 months of antihypertensive therapy. A 58-year-old man was diagnosed as having essential hypertension and hypertensive hypertrophy. The patient was treated with antihypertensive drugs and showed regression of left ventricular hypertrophy on electrocardiograms and echocardiograms. MIBG observations made before and after antihypertensive therapy showed increased heart-to-mediastinum activity ratio and decreased cardiac washout ratio. Despite the many theories addressing the mechanisms of regression of left ventricular hypertrophy, the process is still unclear. In the present case, the improvement of cardiac sympathetic nervous dysfunction might have been related to the regression of left ventricular hypertrophy because the abnormality in MIBG images improved. MIBG, therefore, may be helpful in clarifying the mechanisms of the regression of hypertensive hypertrophy.

3-Iodobenzylguanidine↗
PubMed1995

Bone mineral density of the lumbar spine in patients with ossification of the posterior longitudinal ligament of the cervical spine.

Bone mineral density (BMD) of the lumbar spine in patients with ossification of the posterior longitudinal ligaments of the cervical spine (OPLL) was measured to elucidate the relation of spinal ossification with systemic hyperostotic condition. BMD in the lateral projection had a statistically significant correlation with that in the anteroposterior projection, and the former was considered to reflect the condition more accurately than was the latter, which may include the ossified spinal ligaments. BMD of patients with continuous and mixed types of OPLL was higher than that of those with the segmental type. Patients with OPLL and ossification of the other spinal ligaments had higher BMDs than did those without ossification. These results suggest that the BMD of the lumbar spine may reflect the systemic hyperostotic tendency and advancement of the ossification.

Absorptiometry, Photon↗
PubMed1995

Non-machinery-based system for cell-free, concentrated autogenous ascitic fluid reinfusion.

A non-machinery-based system for the reinfusion of ascitic fluid was developed and assessed. In fundamental studies utilizing bovine serum, this procedure proved economical, quick and useful. The most suitable filter was PS-R (#405-2). Bovine serum with a protein concentration below 3.0 g/dl was treated using this system. Samples containing blood (prepared to 0.5% hematocrit) were also treated, but the treatment time required was double that of serum with the same protein concentration. In both cases the protein recovery ratios were about 90%. We conducted clinical studies on 62 occasions (machinery-based system; 31 times, non-machinery-based system; 31 times) on 19 cases of ascites refractory to treatment with various drugs including diuretics. Clarification of the differences between the non-machinery-based system, indicated the former to be superior. This new procedure is easier because of its use of no machinery, and the high protein recovery ratio proved its usefulness.

Adult↗
PubMed1994

The roles of the N-linked carbohydrate chain of rice alpha-amylase in thermostability and enzyme kinetics.

The thermostability and kinetics of starch hydrolysis were compared between a rice alpha-amylase isozyme Amy1A and its mutant enzyme that lacks an N-linked carbohydrate chain. Elimination of the N-glycosylation site in Amy1A reduced the thermostability of the enzyme. The temperature dependence of the kinetic parameters (Vm and Km) and substrate recognition of the enzymes were also affected by elimination of the N-glycosylation site. These results suggest that the N-linked carbohydrate chain of Amy1A has important roles in the thermostability and reaction kinetics of the enzyme.

Amino Acid Sequence↗
PubMed1994

Homogeneous immunoassay of antibody by use of liposomes made of a model lipid of archaebacteria.

Liposomes made of 1,2-di(3RS,7R,11R-phytanyl)-sn-glycero-3-phosphocholine (DPhyPC), which was synthesized as one of the model lipids existing in archaebacterial halophiles, showed excellent stability. Because of this high stability, DPhyPC liposomes could be constituted high ratios (50%) of N-[4-(p-maleimidophenyl) butyryl] dipalmitoyl phosphatidylethanolamine (MPB-DPPE), and consequently could bind large amounts of antigen (alpha-chymotrypsinogen A) on the liposome surface in comparison with those made of ordinary lipids, such as dipalmitoylphosphatidylcholine (DPPC). Though the characteristics of the DPhyPC liposomal membranes in lysis by the classical complement pathway were similar to those of DPPC liposomes, a high sensitivity and a low detection limit in the liposome immune lysis assay (LILA) of antibodies were attained by binding large amounts of the antigen. Further, by coupling sufficient amounts of antigen, almost all the DPhyPC liposome surface was covered with the antigen, and such liposomes showed higher resistance against non-specific lysis caused by complement activity in serum samples, which may be effective in reducing positive-false errors in LILA.

Animals↗
PubMed1994

Morphologic analysis of the cervical spinal cord, dural tube, and spinal canal by magnetic resonance imaging in normal adults and patients with cervical spondylotic myelopathy.

STUDY DESIGN: Transverse areas of the spinal canal, the dural tube and the spinal cord of the cervical spine of normal adults and patients with cervical spondylotic myelopathy (CSM) were analyzed by magnetic resonance imaging (MRI). OBJECTIVES: Correlations of the results of MRI to clarify the pathogenesis of CSM. SUMMARY OF BACKGROUND DATA: Relationships between the area of the spinal cord and that of the dural tube or the spinal canal have been reported, but there is no report to compare the relationships among the three in patients with CSM and normal adults. METHODS: T1-weighted MR images of the cervical spine of 96 normal adults and 74 patients with CSM were evaluated by measuring the transverse areas of the three structures mentioned above in the axial plane. RESULTS: In normal adults, the maximal transverse area of the spinal cord was 85.8 mm2 at C4/5 and the minimal transverse areas of the dural tube and the spinal canal were 186.0 mm2 at C5/6 and 236.1 mm2 at C4, respectively. At the unaffected level of C3, the ratio of the canal to the spinal cord was significantly higher in CSM patients than in age-matched normal adults. The transverse area of the spinal cord and the ratio at the maximal compression level showed significant correlations with the severity of neurological symptoms. CONCLUSION: These results suggest that the narrow area and high ratio of the spinal canal to the spinal cord are responsible for a static factor in CSM.

Adult↗
PubMed1994

Characterization of soluble CD44 in the circulation of mice. Levels are affected by immune activity and tumor growth.

ELISA determinations revealed substantial concentrations (0.49 to 2.10 micrograms/ml) of soluble CD44 in murine serum, with some variation among normal mouse strains. At least three species of CD44 were identified by immunoprecipitation and SDS-PAGE analysis of serum. The most prominent was indistinguishable in mobility from that extracted from normal and transformed lymphocytes and was estimated in this way to be approximately 90 kDa. A similar estimate resulted from gel filtration under nondenaturing conditions, followed by ELISA. However, lymphocyte membrane-extracted and soluble CD44 had different mobilities after treatment with neuraminidase plus O-glycosidase, and the core protein of soluble CD44 might be 17 to 20 kDa smaller than that of CD44 on lymphocyte membranes. Furthermore, an Ab to cytoplasmic residues of CD44 failed to recognize soluble CD44 recovered from the circulation or in lymphoma culture supernatants. These observations would be consistent with cleavage of CD44 from cell surfaces; and protease inhibitors slowed the loss of CD44 from cultured lymphomas. Serum CD44 levels were significantly reduced in immunodeficient CD17.SCID and BALB/c.Xid mice, and elevated in tumor-bearing mice. Mild graft-vs-host (GVH) reactions also resulted in increased concentrations of CD44, as did autoimmune disease in BXSB and MRL/lpr strains of mice. Serum with high concentrations of CD44 partially blocked the binding of one ligand, hyaluronate, to CD44-bearing hybridoma cells. The degree of inhibition was positively correlated with CD44 concentration. These findings indicate that substantial quantities of CD44 can be released into the circulation by cleavage from cell surfaces and that this process is markedly influenced by immune system activity and tumor growth. The material seemed to be intact and potentially functional.

Amino Acid Sequence↗