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Biomedical subjects

S Katoh

Publications and source records attributed to S Katoh.

At least 181 records · Page 10Linked to original sources
PubMed1994

Phosphorylation by Ca2+/calmodulin-dependent protein kinase II and protein kinase C of sepiapterin reductase, the terminal enzyme in the biosynthetic pathway of tetrahydrobiopterin.

Sepiapterin reductase, the terminal enzyme in the biosynthetic pathway of tetrahydrobiopterin, was stoichiometrically phosphorylated by Ca2+/calmodulin-dependent protein kinase II and protein kinase C (Ca2+/phospholipid-dependent protein kinase) in vitro. Maximal incorporation of phosphate into the enzyme subunit by these was 3.05 +/- 0.05 (n = 4) and 0.74 +/- 0.03 (n = 5) 32P mol per mol enzyme subunit, respectively. The enzyme was not phosphorylated by cyclic nucleotide-dependent protein kinase of either the cAMP-dependent or cGMP-dependent type in this study. Dihydropteridine reductase, another enzyme working in direct supply of tetrahydrobiopterin, was also a good substrate for Ca2+/calmodulin-dependent protein kinase II. Phosphorylation of sepiapterin reductase by these protein kinases modified the kinetic properties of the enzyme. It is likely that these multifunctional Ca(2+)-activated protein kinases may play a role in the regulation of the physiological function of the BH4-generating enzymes in vivo, as was previously found in the case of BH4-requiring enzymes.

Alcohol Oxidoreductases↗
PubMed1994

Purification of secreted alpha-amylases by immunoaffinity chromatography with cross-reactive antibody.

Two isozymes of rice alpha-amylases expressed and secreted by recombinant yeast were purified by immunoaffinity chromatography by using cross-reactive antibody. Antibodies raised against partially purified barley alpha-amylase adsorbed rice alpha-amylases in fermentation broth by a cross-reaction. By use of these antibodies as ligands, rice alpha-amylases were concentrated and purified to a high degree in one-step immunoaffinity chromatography. Because of the differences in the contaminating impurities between the barley alpha-amylase (antigen) from barley malt and rice alpha-amylases (target protein) secreted from yeast, the high purity of eluted alpha-amylases was attained without the use of highly purified antigen for immunization. Utilization of cross-reactive antibodies in immunoaffinity chromatography is useful for the purification of recombinant proteins in the absence of a sufficient amount and high enough purity of the target proteins to be purified.

Antibodies↗
PubMed1994

Oblique odontoid fracture. Case report and review of the literature.

The case of a 89 year old patient with an oblique odontoid fracture is reported. The fracture was oblique extending from the middle of the anterior aspect of the dens to the posterior junction with the body. There was also posterior displacement. This fracture was different from the previously reported two vertical fractures of the odontoid. The possible mechanism of the lesion, and the management of this patient are discussed.

Aged↗
PubMed1994

Spinal cord injuries in Japan: a nationwide epidemiological survey in 1990.

To survey the situation of traumatic spinal cord injuries (SCI) in Japan, the SCI Prevention Committee of the Japanese Medical Society of Paraplegia sent out by mail study charts in the form of questionnaires to institutions nationwide. Using the statistical method of the nationwide epidemiological survey described by Hashimoto et al,1 the annual estimated incidence was obtained from the number of patients registered, and from the questionnaire reply rate at each prefecture. The number of registered patients in 1990 was 3465 and the mean reply rate was 56.6%. There were 2665 registered patients with a neurological deficit (Frankel A-D) and the annual SCI incidence was 39.4 per million. The male:female ratio was 4.3:1 and the ratio of cervical cord injures to those caudal to the cervical cord was 2.9:1. The mean age at the time of injury was 48.5 years. The cause most frequently seen was traffic accidents, the second most frequent being falls from a height. Besides those two, sports injuries and falls on level ground were the third most frequent causes of SCI in the young generation and in elderly people respectively.

Accidental Falls↗
PubMed1994

Increased production of eicosanoids, TXA2, PGI2 and LTC4 in experimental spinal cord injuries.

Arachidonate metabolites have many kinds of bioactivities. Thromboxane A2 (TXA2) stimulates platelet aggregation and vasoconstriction, whereas prostaglandin I2 (PGI2) antagonises its activities. Thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) are determined in biological materials. Production of TXB2, 6-keto-PGF1 alpha and leukotriene C4 (LTC4), which have potent vascular permeability, was measured by radioimmunoassay in experimental spinal cord injured animals. TXB2 level in the rat spinal cord reached a peak concentration of 133.6 +/- 3.8 pmol/g cord, and 6-keto-PGF1 alpha increased to 26.2 +/- 11.7 pmol/g cord 5 minutes after the injury. There was good correlation between TXB2 production and vascular damage as monitored by fluorescein uptake. When OKY-046 ((E)-3-[4-(1-imidazolylmethyl) phenyl]-2-propenoic acid), which selectively inhibits TXA2 synthetase activity, was administered 10 minutes before injury, the increase in TXB2 production was inhibited by more than 80%, but the degree of vascular damage was reduced by only 40%. In the guinea pig spinal cord, LTC4 levels reached a peak concentration of 2.2 +/- 0.4 pmol/g cord 10 minutes after compression, while that of TXB2 reached 146.8 +/- 6.2 pmol/g cord. The increased production of TXB2 was correlated with the degree of compression injury while that of LTC4 production did not. These findings suggest that vasoactive eicosanoids, TXA2, PGI2 and LTC4, play important roles in secondary damage following spinal cord injury, although their roles may be different among species of animals.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Human parvovirus B19-induced aplastic crisis in iron deficiency anemia.

Human parvovirus B19 (HPVB19) infects and replicates in erythroid progenitor cells. Its specific cytotoxic effect on these cells results in aplastic crises in patients with congenital hemolytic anemias. Aplastic crisis due to HPVB19 infection in a healthy girl revealed occult iron deficiency anemia. The condition is characterized by a high serum iron level in the aplastic phase and rapid recovery after administration of iron. Temporary HPVB19-induced red blood cell aplasia could occur in patients with other anemias, particularly those with non-inherited form of hemolysis.

Adolescent↗
PubMed1994

Experimental approaches for the reconstitution of hair in vitro.

When plucked follicles were cultured together with isolated dermal papillae in a collagen gel matrix, outer root sheath cells (ORSCs) grew more rapidly and actively than without the papillae. Cultured dermal papilla cells also activated the colony growth of ORSCs in vitro. These results may suggest the existence of some papilla-derived factor(s) activating the growth of ORSCs. In cultures of excised whole follicles whose dermal papilla had been removed, epithelial cells of bulb matrix origin grew out from the bulbous portion, and formed spikes. When a dermal papilla was implanted close to the follicle, the spikes elongated toward the papilla, and finally reached and surrounded it. This finding suggests that dermal papillae may produce some factor(s) attracting epithelial cells of hair bulb origin. In cultures of excised whole follicles, when the dermal papilla remained originally positioned in contact with the hair bulb matrix, the hair and follicle elongated for more than 1 week. But when the dermal papilla was detached from the bulb matrix, the matrix cells proliferated into the gel and formed a hair-follicle-like structure (folliculoid). In cultures of excised whole follicles whose papilla-matrix junction had been damaged by dispase, elongation of the hair and follicle was almost completely suppressed. Thus, the attachment of the dermal papilla to the bulb matrix appears to be necessary for normal hair and follicle growth.

Cell Division↗
PubMed1994

Involvement of membrane-bound transglutaminase in the invagination of transferrin into rat reticulocyte plasma membrane.

We demonstrated the invagination of transferrin into reticulocyte plasma membrane to learn whether membrane-bound transglutaminase (TGase, a Ca(2+)-dependent enzyme) is involved in this invagination. The invagination was assessed by acid-resistance assay and antibody-inaccessibility assay. The invagination was blocked in the absence of ATP. [14C]Putrescine, a substrate for TGase, was incorporated into the membrane during the invagination. This incorporation was decreased in the absence of ATP or transferrin and was completely blocked in the presence of monodansylcadaverine or EGTA. The TGase inhibitor and EGTA also decreased the invagination. In the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis, the labeling of 43 kDa membrane protein with [14C]putrescine and the increase in aggregation of proteins were observed in a transferrin-, ATP- and Ca(2+)-dependent manner. These results provide the first evidence for modification of protein by TGase accompanying the invagination of transferrin into the membrane, and suggest that membrane-bound TGase is involved in the invagination step of endocytosis.

Acids↗
PubMed1994

Pleural multicystic mesothelial proliferation.

We report a rare case of pleural multicystic mesothelial proliferation occurring in a 62-year-old Japanese woman. Macroscopically, the lesion consisted of multiple thin wall cysts containing clear serous fluid. Histologic studies, including hematoxin-eosin stain, as well as the immunohistochemical method, revealed that the lesion was mesothelial in origin and consistent with a reactive change.

Antigens↗
PubMed1994

Malignant T cell lymphoma associated with sarcoidosis.

We report an unusual case of non-Hodgkin T cell lymphoma associated with sarcoidosis. A 44-year-old woman was histologically diagnosed as having sarcoidosis in 1966. Diffuse interstitial lung disease and erythematous skin nodules disappeared following steroid therapy. Twenty years after sarcoidosis onset erythematous nodosum recurred and biopsy specimens revealed non caseating epithelioid granuloma. Thirty-seven months later a malignant T cell lymphoma developed in the skin portion where sarcoid lesions recurred. We discuss the possible relationship between the sarcoid inflammatory process and the development of a malignant T cell clone as origin of the T cell lymphoma.

Adult↗
PubMed1994

[A case of pulmonary tuberculosis with HIV infection--review of 5 cases in Japan].

Recently we encountered a case of pulmonary tuberculosis with HIV infection. The patient was 54-years old male. His chief complaints were anemia, emaciation and severe diarrhea. He was admitted to our hospital on September 18, 1992. He had been diagnosed in another clinic as having pulmonary tuberculosis before the admission to our hospital. His chest films taken on admission revealed homogeneous infiltrates with cavitation in right upper lobe. Serial chest X-rays consisted with the findings of post-primary tuberculosis. Sputum smear for acid fast bacilli was positive. From his clinical manifestations and life-history, we had a suspicion that he had infected with HIV. Laboratory findings were as follows: serum albumin level was 1.9 g/dl, CRP was 10.2 mg/dl, serological tests for HIV were positive by EIA, IFA and western blott method, total lymphocyte count was 819/microliters, CD4+ T lymphocyte count was 120/microliter CD4+/CD8+ ratio was 0.2. He was treated with AZT, isoniazid, streptomycin and rifampicin. The disease progressed rapidly and interstitial pneumonia, jaundice and clouding of consciousness appeared at the terminal stage. He expired on October 14, 1992. In this paper, the authors reported a case of pulmonary tuberculosis with HIV infection and also reviewed 5 cases of pulmonary tuberculosis associated with HIV in Japan.

Adult↗
PubMed1994

[Clinical study of a new injectable cephem, FK037, for acute bacterial prostatitis].

FK037, a new injectable cephem antibiotic, was administered in the treatment of 13 acute bacterial prostatitis (mean age 53.5, range 30-79), and its effectiveness and safety were evaluated. The human prostatic fluid (PF) concentration of FK037 on 7 specimens 1 hour after 1 g i.v.d., was in the range of 0.87-7.47 micrograms/ml (mean +/- SD, 3.43 +/- 2.23 micrograms/ml), whereas, the serum concentration averaged 45.3 +/- 2.88 micrograms/ml, the ratio of PF/serum consequently being 0.08 +/- 0.05. In the clinical study, 1g of FK037 was administered to 13 patients by i.v.d. twice a day for 7-9 days. Bacteriological eradication on expressed prostatic secretion (EPS) was obtained for all clinical isolates which included 11 strains of Escherichia coli (MIC < or = 0.05 microgram/ml), 2 of Enterococcus faecalis, and each one of Staphylococcus aureus and Morganella morganii. Symptomatical cure was 100% in all cases. As for safety profile, no side effects were noted. In laboratory values, slight elevation of transaminase were detected in 3 cases, but they were transient and returned to normal 1-2 weeks after completion of the therapy. We conclude that FK037 is highly effective in the treatment of acute bacterial prostatitis, and is well tolerated in comparison with other relative antimicrobials.

Acute Disease↗
PubMed1994

Neurological recovery after conservative treatment of cervical cord injuries.

We reviewed a series of 53 patients with closed traumatic complete injuries of the cervical spinal cord. They were admitted within two days to a spinal injuries centre, treated conservatively by six weeks of bedrest and skull traction, then mobilised in a neck support for six weeks. Eight patients had temporary neurological deterioration, four spontaneously and four after cervical manipulation; seven of these recovered to the initial neurological level without surgery. Of 40 patients followed for more than 12 months, 19 recovered useful motor power in local muscles which were initially paralysed (zonal recovery); one patient showed distal motor recovery. Zonal recovery did not correlate with the mechanism of skeletal injury or with the degree of residual canal stenosis. Sensory sparing and an initial neurological level higher than the level of skeletal injury were both good prognostic signs for zonal recovery.

Adolescent↗
PubMed1993

Dephosphorylation on tyrosine of epidermal growth factor receptor is inhibited by Ca2+ pretreatment in isolated liver membrane.

The autophosphorylation of epidermal growth factor receptor of the liver membrane was enhanced by pretreatment with 1 mM Ca2+. This enhancement was blocked by 30 microM genistein, but not by 30 microM H-7. In immunoblotting analysis, the amount of phosphotyrosine increased in the Ca(2+)-pretreated membrane. When dephosphorylation processes were studied, receptor dephosphorylation occurred in a time-dependent manner in the untreated membrane, but not in the Ca(2+)-pretreated membrane. In the presence of sodium vanadate, receptor phosphorylation increased in the untreated membrane, but not in the Ca(2+)-pretreated membrane. Inhibition of dephosphorylation did not occur in the membrane pretreated with Ca2+ in the presence of monodansylcadaverine, a transglutaminase (TGase) inhibitor. These results suggest that Ca2+ pretreatment causes the inhibition of some protein tyrosine phosphatase via a Ca(2+)-involved mechanism such as activation of TGase and results in the enhancement of receptor phosphorylation.

Adenosine Triphosphate↗
PubMed1993

(R)-1,2,3,4-tetrahydro[1]benzothieno[2,3-c]pyridines: novel optically active compounds with strong 5-HT1A receptor binding ability exhibiting anticonflict activity and lessening of memory impairment.

(R)-1,2,3,4-Tetrahydro[1]benzothieno[2,3-c]pyridine derivatives (60-114) were synthesized. The (R)-isomers have affinity for the 5-HT1A receptor while the (S)-isomers have no such ability. The affinity of the (R)-isomers was discussed on the basis of structure-activity relationships between the affinity and hydrophobicity of the (R)-isomers. Compounds 71 and 107, which are representative derivative compounds, have anticonflict activity and lessening of memory impairment. In particular, compound 107 cannot bind to receptors other than the 5-HT1A receptor, demonstrating that it is a unique compound with a different mechanism of action from that of conventional anxiolytics.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1993

Magnetic resonance imaging study on the results of surgery for cervical compression myelopathy.

The morphologic changes and signal intensity of the spinal cord on preoperative magnetic resonance images were correlated with postoperative outcomes in 74 patients undergoing decompressive cervical surgery for compressive myelopathy. The transverse area of the spinal cord on T1-weighted images at the level of maximum compression was closely correlated with the severity of myelopathy, duration of disease, and recovery rate as determined by the Japanese Orthopaedic Association score. In patients with ossification of the posterior longitudinal ligament or cervical spondylotic myelopathy, the increased intramedullary T2-weighted magnetic resonance imaging signal at the site of maximal cord compression and duration of disease significantly influenced the rate of recovery. A multiple regression equation was then developed with these three variables to predict surgical outcomes.

Cervical Vertebrae↗
PubMed1993

Nucleotide sequence of the Mn-stabilizing protein gene of the thermophilic cyanobacterium Synechococcus elongatus.

The nucleotide sequence of the psbO gene encoding the extrinsic 33 kDa protein (the Mn-stabilizing protein) from the thermophilic cyanobacterium Synechococcus elongatus was determined. The deduced amino acid sequence consisted of 272 residues; 26 for the signal peptide and 246 for the mature protein. The amino acid sequences of nine proteolytic peptides from the isolated protein completely agreed with the deduced amino acid sequence. Several unique variations of amino acids were found in the primary structure, of which some may be related to the high thermostability of the protein.

Amino Acid Sequence↗