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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 325 records · Page 18Linked to original sources
PubMed1999

Large bursa formation associated with osteochondroma of the scapula: a case report and review of the literature.

Bursitis or large bursa formation associated with osteochondroma has rarely been reported. A 33-year-old male presented with upper back pain, a rapidly developing mass beside the lateral border of his right scapula and snapping elicited by movement of the scapula. Plain radiograms and CT revealed osteochondroma on the ventral surface of the scapula without any unmineralized component and a huge cystic lesion around the osteochondroma. Aspiration of the cystic lesion showed the presence of sero-sanguineous fluid. MRI following the aspiration showed a thin cartilaginous cap with distinct outer margin and no soft tissue mass around the cap. Pathological examinations confirmed the diagnosis of osteochondroma with the large bursa formation. Clinical examination 19 months postoperatively showed an uneventful clinical course.

Adult↗
PubMed1999

Auxin polar transport and flower formation in Arabidopsis thaliana transformed with indoleacetamide hydrolase (iaaH) gene.

Involvement of auxin polar transport in flower formation of Arabidopsis thaliana was studied using a pinformed (pin) mutant (Rpin) transformed with the indoleacetamide hydrolase (iaaH) gene and the phenocopy of the pin mutant, which was induced by 9-hydroxyfluorene-9-carboxylic acid (HFCA). The application of indoleacetamide (IAM) did not change aberrant structure of the aerial part of Rpin (pin/pin), but extremely inhibited its root growth. Treatment with IAM increased the endogenous concentrations of free and conjugated IAA in Rpin normal (pin/+ or +/+) due to the expression of the iaaH gene, to 140% and 428% of those in non-treated plants, respectively, and those in Rpin to 378% and 120%, respectively. The activity of IAA polar transport in the inflorescence axis of Rpin remained low even in the presence of IAM, the activity being almost similar, to that in the pin mutant. The activity of IAA polar transport in the HFCA-induced phenocopy of the pin mutant was also extremely low, and it was not restored by the simultaneous application of IAA. Arabidopsis thaliana responded to HFCA applied from 7 to 11 d and from 25 to 29 d after germination in the wild-type plant (Enkheim ecotype) and the late flowering mutant (fb mutant), respectively. These results suggest that the construction of the system of auxin polar transport and its normal activities are essential for the differentiation and the formation of floral meristem in the early growth stage of Arabidopsis thaliana.

Amidohydrolases↗
PubMed1999

Pathology of ossification of the posterior longitudinal ligament and ligamentum flavum.

Ossification takes place in the posterior longitudinal ligament and ligamentum flavum of the spine under certain conditions of unknown nature. Ossification of these ligaments has the following characteristics: (1) ectopic bone formation occurring within the spinal ligaments; (2) ossification accompanies ligamentous tissue hyperplasia and cell proliferation; (3) before ossification, fibrocartilaginous cell proliferation, calcification and tissue resorption with vascular ingrowth take place sequentially; (4) ossification of the ligament has a specific site of predilection and often occurs in combination with senile ankylosing vertebral hyperostosis (Forestier's disease) or diffuse idiopathic skeletal hyperostosis; and (5) ossification and symptom development are remarkably more frequent in the Japanese population. Recent studies revealed that bone morphogenetic proteins and transforming growth factor-beta played an important role in the matrix hyperplasia and ossification of the spinal ligament, and metabolic and genetic aberration often characterized patients suffering from this disorder.

Humans↗
PubMed1999

The effect of erythropoietin on interleukin-1beta mediated increase in nitric oxide synthesis in vascular smooth muscle cells.

OBJECTIVE: Recently, we observed that recombinant human erythropoietin (rHuEPO) inhibits the interleukin (IL)-1beta induced nitric oxide (NO) production and inducible NO synthase (iNOS) expression in cultured rat vascular smooth muscle cells (VSMC). The mechanisms of these inhibitory effects of rHuEPO were evaluated. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was performed to identify a specific erythropoietin receptor (EpoR). Tyrosine phosphorylation of phospholipase C (PLC) was analyzed by combination of immunoprecipitation and Western blotting. Protein kinase C (PKC) activities were analyzed by phosphorylation assay of myelin basic protein (MBP4-14). VSMC were incubated with test agents for 24 h and nitrite as a stable NO metabolite was measured. iNOS mRNA and protein expression was analyzed by Northern and Western blotting, respectively. RESULTS: RT-PCR analysis revealed that EpoR m-RNA was expressed; furthermore, it might be alternatively spliced in VSMC. rHuEPO induced tyrosine phosphorylation of PLC-gamma1 and activation of PKC. rHuEPO inhibited not only IL-1beta induced nitrite production, but also the expression of iNOS mRNA and protein. These inhibitory effects of rHuEPO were reversed in the presence of PKC inhibitors, calphostin C (1 pmol/l) or staurosporine (10 nmol/l). PKC activation by phorbol myristate acetate inhibited nitrite production. The inhibitory effect of rHuEPO on IL-1beta induced nitrite production was also eliminated in PKC depleted cells or in the existence of anti-EpoR antibody. CONCLUSION: rHuEPO inhibits IL-1beta induced NO production by suppressing iNOS mRNA and protein expressions through EpoR, and the PLC-gamma1 and PKC pathway may be involved.

Animals↗
PubMed1999

FILAMENTOUS FLOWER controls the formation and development of arabidopsis inflorescences and floral meristems.

Phenotypic analysis of single and multiple mutants as well as in situ localization analysis of the expression patterns of floral genes have revealed that the FIL AMENTOUS FLOWER (FIL) gene plays important roles in establishing the inflorescence in Arabidopsis. As previously reported, the fil mutant generates clusters of both filamentous structures and flowers with floral organs of altered number and shape. The structural resemblance of the filamentous structures to peduncles and the expression pattern of the APETALA1 (AP1) gene have shown that these filamentous structures are underdeveloped flowers that fail to form receptacles and floral organs, indicating that one of the roles of the FIL gene is to support the development of the floral meristem. That FIL also is involved in fate determination in the floral meristem is demonstrated by the homeotic conversion of flowers to inflorescences in fil ap1 double mutants and in fil ap1 cauliflower triple mutants. In double mutants with flowering-time loci (i.e., f t or f wa), leafy (lf y), and unusual floral organs (ufo), filamentous structures are formed, but very few or no flowers with floral organs develop. The enhanced phenotype in the fil ap1 and the fil lfy double mutants suggests that the FIL protein may work together with AP1 and LFY proteins. The FIL gene also may be involved in the cell fate determination of floral organ primordia, possibly by controlling the spatial expression patterns of the class A and C floral organ identity genes.

Arabidopsis↗
PubMed1999

Enhanced sonodynamic antitumor effect of ultrasound in the presence of nonsteroidal anti-inflammatory drugs.

The antitumor effects of non-steroidal anti-inflammatory drugs, tenoxicam and piroxicam, against sarcoma 180 cells cultured in 7-week-old male mice were examined in vitro under ultrasonic irradiation. The survival rate of tumor cells when tenoxicam or piroxicam was added to sarcoma 180 suspension under ultrasonic irradiation was significantly lower than that when ultrasound alone was applied. Furthermore, when L-histidine, a scavenger of singlet oxygen and hydroxyl radical, or D-mannitol, a scavenger of hydroxyl radical, was used concurrently, the survival rate of tumor cells was significantly higher with L-histidine. From the above findings, it is surmised that tenoxicam and piroxicam increase the antitumor effects of ultrasound by increasing the production of singlet oxygen and other active oxygen species.

Animals↗
PubMed1999

Prevention of lung metastasis by intra-tumoral injection of Cepharanthin and staphylococcal enterotoxin B in transplantable rat osteosarcoma.

The antitumor effect of intra-tumoral injection of Cepharanthin, a biscoclaurin alkaloid extracted from Stephania cephalanta Hayata, and staphylococcal enterotoxin B was evaluated using F344 male rats bearing transplantable rat osteosarcoma, S-SLM. A macroscopic lung metastatic nodule of tumor was transplanted into the subcutaneous back space, and 0.5 mg of Cepharanthin and 2 pg of staphylococcal enterotoxin B were injected into the tumor on days 12, 13 and 14. On day 28, all animals were killed with an overdose of pentobarbital sodium, and the transplanted tumors and lungs were examined. The wet weight of the lungs of the rats treated with Cepharanthin and staphylococcal enterotoxin B was significantly lower, and apoptosis in the lung metastatic nodules was significantly higher than that of the control or that of rats treated with only Cepharanthin or staphylococcal enterotoxin B. In the transplanted tumors, infiltration of TRAP (tartrate-resistant acid phosphatase)-positive multinucleated giant cells was prominent in the rats treated with Cepharanthin and staphylococcal enterotoxin B. These findings indicate that intra-tumoral injection of Cepharanthin and staphylococcal enterotoxin B induced infiltration of TRAP-positive multinucleated giant cells within the transplanted rat osteosarcoma, and reduced lung metastasis.

Acid Phosphatase↗
PubMed1999

[A case of Chlamydia pneumonia and systemic lupus erythematosus (SLE) pleurisy].

A 40-year-old female was admitted with right chest pain. SLE was absent from her past history, although she complained of polyarthralgia in winter. Atypical pneumonia/pleuritis was suspected by chest X-ray film, showing a nodular shadow in the right lower field and moderate pleural effusion. Chlamydia pneumonia was diagnosed by elevated anti-C. psittsci antibody, while characteristics of pleural fluid revealed serositis accompanied by SLE because of the high titered anti-DNA antibody and the low titered complement. She was cured by clarithromycin and subsequent administration of prednisolone and cyclophosphamide.

Adult↗
PubMed1999

Failure of cdc2 promoter activation and G(2)/M transition by ANG II and AVP in vascular smooth muscle cells.

The physiological role of the vasoconstrictive hormones arginine vasopressin (AVP) and angiotensin II (ANG II) in the development of vascular hyperplasia is still unclear. We examined the effects of these hormones on cell cycle regulation of cultured rat vascular smooth muscle cells (VSMC). AVP and ANG II were able to induce G(1)/S transition and DNA synthesis in serum-starved quiescent VSMC but failed to promote further progression into G(2)/M phases. AVP and ANG II enhanced the expression and activity of cdk2, cyclin E, and proliferating cell nuclear antigen but did not induce expression of cdc2/cyclin B complex, a critical regulator of G(2)/M transition. The failure of cdc2 mRNA induction was found to be caused by a defect in cdc2 promoter activation. Binding of free E2F-1 to the cdc2 promoter did not occur in hormone-treated VSMC, which may account for the defective induction of cdc2. The absence of cdc2 promoter activation and G(2)/M transition may be important for the prevention of hyperplasia under physiological conditions but underlies the hypertrophy of VSMC.

Angiotensin II↗
PubMed1999

Mechanism of biphasic response of renal nerve activity during acute cardiac tamponade in conscious rabbits.

Renal sympathetic nerve activity (RSNA) responses to acute cardiac tamponade were studied in conscious rabbits with all reflexes intact (Int) or after either surgical sinoaortic denervation (SAD) or administration of intrapericardial procaine (ip-Pro) or intravenous procaine (iv-Pro). In Int rabbits, the mean arterial pressure (MAP) remained relatively constant until the pericardial volume reached 7. 7 ml, whereas the RSNA increased to 226% [compensated cardiac tamponade (CCT)], then, at a pericardial volume of 9.3 ml, the MAP fell sharply and RSNA decreased to 34% [decompensated cardiac tamponade (DCT)]; 1 min after cessation of pericardial infusion, an intravenous injection of naloxone resulted in increases in both MAP and RSNA. In SAD rabbits, RSNA did not alter throughout CCT and DCT, but increased on injection of naloxone. In ip-Pro rabbits, RSNA increased during CCT but did not decrease during DCT, whereas, in iv-Pro rabbits, the RSNA response was similar to that in Int rabbits. These results indicate that RSNA responses to cardiac tamponade are biphasic, with an increase during CCT and a decrease during DCT. Sinoaortic baroreceptors are involved in mediating the increase in RSNA, whereas cardiac receptors may be involved in mediating the decrease in RSNA. An endogenous opioid may be responsible for the decrease in RSNA seen during DCT.

Acute Disease↗
PubMed1999

Massive pulmonary hemorrhage due to cytomegalovirus infection in a Japanese patient with alpha-1-antitrypsin-deficient emphysema.

Although alpha(1)-antitrypsin (AAT) deficiency is one of the most common hereditary diseases and a recognized cause of emphysema in Caucasians, variants of this deficiency are extremely rare among Orientals. We present here a Japanese emphysema patient with the AAT deficiency variant originally identified as S(iiyama). After an 8-year follow-up period, the patient suffered from repeated pulmonary Pseudomonas aeruginosa infection for 4 years. He died suddenly of massive pulmonary hemorrhage. The pathologic examination revealed a necrotic hematoma in the right S10 lobe, which exhibited pneumonia due to cytomegalovirus (CMV) infection. Pulmonary hemorrhage due to CMV can occur and be fatal in patients with emphysema and AAT deficiency.

Adult↗
PubMed1999

XAIP1: a Xenopus homologue of yeast actin interacting protein 1 (AIP1), which induces disassembly of actin filaments cooperatively with ADF/cofilin family proteins.

We carried out affinity column chromatography using Xenopus ADF/cofilin (XAC), identified several polypeptides in oocytes specifically bound to this column with actin, and isolated a full-length cDNA clone for a 65 kDa protein in this fraction. The predicted amino acid sequence revealed that the 65 kDa protein has seven obvious WD repeats and exhibits striking homology with yeast actin interacting protein 1 (AIP1). Thus, we designated this protein Xenopus AIP1 (XAIP1). We purified XAIP1 from Xenopus oocytes, and its interaction with actin was characterized by a pelleting assay, photometrical analysis and electron microscopy. Although XAIP1 itself cosedimented with F-actin and increased unsedimented actin to some extent, it induced a rapid, drastic disassembly of actin filaments associated with XAC. Electron microscopic observation revealed that XAIP1 severs actin filaments in the presence of XAC. To elucidate the in vivo effects of XAIP1, the purified protein was injected into blastomeres at the two-cell stage. Although the localization of XAIP1 was similar to that of XAC, at the cortical cytoskeleton and diffusely in the cytoplasm, injection of a large amount of XAIP1 arrested development and abolished the strong cortical staining of both actin and XAC. From these results, we concluded that XAIP1 regulates the dynamics of the cortical actin cytoskeleton cooperatively with XAC in eggs.

Actin Depolymerizing Factors↗