Search PubMed⌕ Search

Biomedical subjects

K Kataoka

Publications and source records attributed to K Kataoka.

At least 127 records · Page 7Linked to original sources
PubMed1999

CNS-specific prostacyclin ligands as neuronal survival-promoting factors in the brain.

Prostacyclin (PGI2) is a critical regulator of the cardiovascular system, via dilatation of vascular smooth muscle and inhibition of platelet aggregation (Moncada, S. 1982, Br. J. Pharmacol., 76, 3). Our previous studies demonstrated that a novel subtype of PGI2 receptor, which is clearly distinct from a peripheral subtype in terms of ligand specificity, is expressed in the rostral region of the brain, e.g. cerebral cortex, hippocampus, thalamus and striatum, and that (15R)-16-m-17,18,19,20-tetranorisocarbacyclin (15R-TIC) and 15-deoxy-16-m-17,18,19,20-tetranorisocarbacyclin (15-deoxy-TIC) specifically bind to the central nervous system (CNS)-specific PGI2 receptor. Here, we report that these CNS-specific PGI2 receptor ligands, including PGI2 itself, prevented the neuronal death. They prevented apoptotic cell death of hippocampal neurons induced by high (50%) oxygen atmosphere, xanthine + xanthine oxidase, and serum deprivation. IC50s for neuronal death were approximately 30 and 300 nM for 15-deoxy-TIC and 15R-TIC, respectively, which well correlated with the binding potency for the CNS-specific PGI2 receptor. 6-Keto-PGF1alpha (a stable metabolite of PGI2), peripheral nervous system-specific PGI2 ligands and other prostaglandins (PGs) than PGI2 did not show such neuroprotective effects. In vivo, 15R-TIC protected CA1 pyramidal neurons against ischaemic damage in gerbils. These results indicate that CNS-specific PGI2 ligands have neuronal survival-promoting activity both in vitro and in vivo, and may represent a new type of therapeutic drug for neurodegeneration.

Animals↗
PubMed1999

Multilevel vertebral body replacement with a titanium mesh spacer for aneurysmal bone cyst: technical note.

A 64-year-old male presented with abrupt tetraparesis caused by a minor impact. Diagnostic images obtained on admission showed an aneurysmal bone cyst visible in the cervical spine at the fourth to upper sixth level, although the patient had been wearing a halo brace to diminish the symptoms. The vertebral body from the fourth to the sixth level was dissected, and this space was packed with a titanium cage filled with ceramic bone fragments mixed with fibrin glue. The combination of a titanium cage and an anterior locking plate can be made easily for anterior spinal fusion with enough rigidity to maintain the necessary space during fusion without any major support equipment. Both edges of the titanium mesh cage cut into the vertebral body to hold the cage in place. The other part, the titanium plate, makes it secure until ceramic bone fragments in the cage promote bony ingrowth for fusion.

Bone Cements↗
PubMed1999

Cytokine expression and induction of acinar cell apoptosis after pancreatic duct ligation in mice.

To clarify the role of cytokines and acinar cell apoptosis in the pathogenesis of acute pancreatitis, we investigated the expression of intrapancreatic cytokines and apoptosis-related molecules in mice after pancreatic duct ligation (PDL). From day 1 or 3 after PDL, the expression of interleukin-1alpha (IL-1alpha), IL-1beta, IL-1 receptor antagonist, IL-6, IL-10, and tumor necrosis factor (TNF-alpha) mRNA were up-regulated in the pancreas, suggesting that these cytokines may be involved in the development of pancreatitis after PDL. Acinar cell apoptosis was observed in the pancreas at rates of 0.13 +/- 0.03, 1.32 +/- 0.38, and 0.86 +/- 0.23% on days 1, 3, and 7 after PDL, respectively. Significant increases in intrapancreatic mRNA levels of TNF-alpha, Fas ligand (FasL), and IL-1beta-converting enzyme (ICE) were observed from day 3 after PDL with the appearance of acinar cell apoptosis. The serum amylase activity peaked on day 1 after PDL and gradually decreased on days 3 and 7 after PDL. These results suggest that acinar cell apoptosis induced after PDL may modulate the progression of acute pancreatitis by reducing the release of digestive enzymes and may therefore be a host defense mechanism, and that acinar cell apoptosis after PDL may be mediated by the TNF-alpha and/or Fas/FasL and ICE system.

Amylases↗
PubMed1999

Reduction of the side effects of an antitumor agent, KRN5500, by incorporation of the drug into polymeric micelles.

For intravenous (i.v.) injection of a water-insoluble antitumor drug, KRN5500, we have successfully incorporated KRN5500 into polymeric micelles. In the present study, in vitro and in vivo anti-tumor activity against several human tumor cell lines and toxicity in mice of polymeric micelles incorporating KRN5500 (KRN/m) were evaluated in comparison with those of the prototype KRN5500. KRN/m was found to express similar antitumor activity to KRN5500 in the in vitro and in vivo systems. However, the vascular damage and liver focal necrosis observed with KRN5500 i.v. injection were not seen when KRN/m was administered i.v. Therefore, we expect that KRN/m will be superior to KRN5500 for clinical use and that the methodology of polymeric micelle drug carrier systems can be applied to other water-insoluble drugs.

Animals↗
PubMed1999

Secretion of functional salivary peptide by Streptococcus gordonii which inhibits fimbria-mediated adhesion of Porphyromonas gingivalis.

Porphyromonas gingivalis, a putative periodontopathogen, can bind to human salivary components with its fimbriae. We have previously shown that fimbriae specifically bind to a peptide domain shared by a major salivary component, i.e., proline-rich (glyco)proteins (PRPs). The synthetic domain peptide PRP-C (pPRP-C) significantly inhibits the fimbrial binding to PRPs. In this study, a recombinant strain of Streptococcus gordonii secreting pPRP-C was generated as a model of a possible approach to prevent the oral colonization by the pathogen. A duplicate DNA fragment (prpC) encoding pPRP-C was obtained by self-complementary annealing of synthetic oligonucleotides. prpC was connected downstream to a promoter and a gene encoding a signal peptide of Streptococcus downei glucosyltransferase I in frame. The linked fragments were inserted into the plasmid pMNK-4 derived from pVA838. The constructed plasmid was inserted to produce the transformant S. gordonii G9B, which then successfully secreted recombinant pPRP-C (r-pPRP-C) of the expected size. The concentrated bacterial culture supernatant containing r-pPRP-C inhibited the binding of P. gingivalis cells and fimbriae to PRP1 in a dose-dependent manner up to 72 and 77%, respectively. The r-pPRP-C concentrate also inhibited the coaggregation of P. gingivalis with various streptococcal strains as effectively as synthetic pPRP-C in a dose-dependent manner. Collectively, pPRP-C was found to be able to prevent P. gingivalis adherence to salivary receptor protein and plaque-forming bacteria. These results suggest that this recombination approach with a nonperiodontopathic bacterium may be suitable for the therapeutic prevention of P. gingivalis adherence to the oral cavity.

Bacterial Adhesion↗
PubMed1999

Distribution of Porphyromonas gingivalis strains with fimA genotypes in periodontitis patients.

Fimbriae (FimA) of Porphyromonas gingivalis are filamentous components on the cell surface and are thought to play an important role in the colonization and invasion of periodontal tissues. We previously demonstrated that fimA can be classified into four variants (types I to IV) on the basis of the nucleotide sequences of the fimA gene. In the present study, we attempted to detect the four different fimA genes in saliva and plaque samples isolated from patients with periodontitis using the PCR method. Four sets of fimA type-specific primers were designed for the PCR assay. These primers selectively amplified 392-bp (type I), 257-bp (type II), 247-bp (type III), and 251-bp (type IV) DNA fragments of the fimA gene. Positive PCR results were observed with reference strains of P. gingivalis in a type-specific manner. All other laboratory strains of oral and nonoral bacteria gave negative results. The sensitivity of the PCR assay for fimA type-specific detection was between 5 and 50 cells of P. gingivalis. Clinical samples were obtained from saliva and subgingival plaque from deep pockets (>/=4 mm) of 93 patients with periodontitis. Bacterial genomic DNA was isolated from the samples, and the targeted fragments were amplified by PCR. The presence of P. gingivalis was demonstrated in 73 patients (78.5%), and a single fimA gene was detected in most patients. The distribution of the four fimA types among the P. gingivalis-positive patients was as follows: type I, 5.4%; type II, 58.9%; type III, 6. 8%; type IV, 12.3%; types I and II, 6.8%; types II and IV, 2.7%; and untypeable, 6.8%. P. gingivalis with type II fimA was detected more frequently in the deeper pockets, and a significant difference of the occurrence was observed between shallow (4 mm) and deep (>/=8 mm) pockets. These results suggest that P. gingivalis strains that possess type II fimA are significantly more predominant in periodontitis patients, and we speculate that these organisms are involved in the destructive progression of periodontal diseases.

Adult↗
PubMed1999

Assessment of exocrine pancreatic dysfunction in chronic pancreatitis.

The clinical diagnosis of chronic pancreatitis is usually based on imaging studies, pancreatic function tests, and the presence of characteristic clinical features. In Japan, diagnostic criteria for chronic pancreatitis were established in 1995. The secretin test (a duodenal intubation test) and the combination of noninvasive tests, N-benzoyl-L-tyrosyl-p-aminobenzoic acid (BT-PABA) and fecal chymotrypsin (FCT), have been recommended for evaluating exocrine pancreatic function in patients with chronic pancreatitis. In the present study, the diagnostic value of these two noninvasive tests was compared to the secretin test. Although noninvasive tests are less sensitive and specific for determining exocrine pancreatic dysfunction than the secretin test, greater reliability for diagnosing chronic pancreatitis can be obtained by performing the BT-PABA and FCT simultaneously. Assessment of exocrine pancreatic function is important not only to diagnose chronic pancreatitis but also to decide a treatment method with pancreatic enzyme preparation.

4-Aminobenzoic Acid↗
PubMed1999

Structural fragility and inflammatory response of ruptured cerebral aneurysms. A comparative study between ruptured and unruptured cerebral aneurysms.

BACKGROUND AND PURPOSE: Despite technical advances in endovascular and microsurgical treatment, patients with aneurysmal subarachnoid hemorrhage still have a high mortality and morbidity rate. To improve the treatment results in patients with aneurysms, we must better understand the pathophysiology of cerebral aneurysms and the mechanisms leading to their rupture. Therefore, we studied the pathological differences between unruptured and ruptured aneurysms. METHODS: Ruptured (n=44) and unruptured (n=27) aneurysms were obtained at surgery. The aneurysmal endothelium was scored from 0 (normal) to 5 (complete disruption) by using a scanning electron microscope. The aneurysmal wall was evaluated by immunohistochemical methods. The wall structure was scored from 1 (dense collagen and rich, smooth muscle cells) to 5 (hyaline-like structure). The degree of inflammatory cell invasion into the wall was also scored from 0 (very few cells) to 3 (many cells). RESULTS: Ruptured aneurysms manifested significant endothelial damage (score of 3.7 versus 0.8; Mann-Whitney U test, P<10(-3)), significant structural changes of the wall (3.7 versus 1.7, P<10(-5)), and significant inflammatory cell invasion (2.2 versus 0.8, P<10(-4)) compared with unruptured aneurysms. There was a significant correlation between the score for wall structure and the score for inflammatory cell invasion (Rs=0. 63; Spearman rank correlation test, P<10(-5)). The pathophysiology of several symptomatic unruptured aneurysms was similar to that of ruptured aneurysms. CONCLUSIONS: We conclude that the pathophysiology of unruptured, asymptomatic and ruptured aneurysms is different. The wall of ruptured aneurysms was found to be fragile, possibly because macrophage infiltration into the aneurysmal wall resulted in loss of smooth muscle cells and in degradation of matrix proteins.

Aneurysm, Ruptured↗
PubMed1999

Selective delivery of adriamycin to a solid tumor using a polymeric micelle carrier system.

The anticancer drug, adriamycin (ADR), was incorporated by physical entrapment into polymeric micelles for selective delivery to a murine solid tumor colon adenocarcinoma 26 (C 26). In vivo antitumor activity of ADR was greatly enhanced by this incorporation into polymeric micelles. Using one polymeric micelle delivery system, the tumor completely disappeared at two doses, while free ADR exhibited a fair inhibition effect on tumor growth only at the maximum tolerated dose. Biodistribution analysis revealed that the physically entrapped micellar ADR accumulated at tumor sites in a highly selective manner. These results indicate that these polymeric micelles are a promising system for delivering hydrophobic anticancer drugs selectively to solid tumor sites using a passive targeting mechanism.

Adenocarcinoma↗
PubMed1999

[A case of diffuse pleural mesothelioma disclosed by a 7 mm tumor shadow on chest X-ray film during a regular physical checkup].

We encountered a patient with diffuse pleural mesothelioma pointed out by a tumor shadow 7 mm in diameter on a chest X-ray film obtained during a regular physical checkup. Computed tomography (CT) scans disclosed several small tumors, slightly thickened pleura, and a small amount of pleural effusion. A cytological examination of the effusion, as well as a bronchoscopic examination, were both unable to detect any evidence of malignancy. The patient was referred to the respiratory medicine department of our hospital, where further bronchoscopic examinations were performed but no conclusive diagnosis was obtained. The patient was therefore referred to our department. CT scans revealed enlarged tumors, markedly thickened pleura, and an increase in pleural effusion. This time a cytological analysis of effusion samples was positive for malignant mesothelioma cells. A pleuropneumonectomy was performed, but tumor cells were partially exposed on the dissected surface. Recurrent tumors were disclosed by CT scans 15 months later. Our conclusion was that a thoracoscopic examination should have been performed for diagnostic purposes at an earlier stage.

Humans↗
PubMed1999

[Association between the results of blood test and blood PCB level of chronic Yusho patients twenty five years after the outbreak].

A cross-sectional study on the association between the results of blood test and the blood concentration of PCB was conducted on the chronic Yusho patients. The subjects were 265 Yusho patients (134 men and 131 women) who received the annual nationwide health examination for Yusho in 1993. The results of the blood test and questionnaire survey at the annual health examination were used for the analyses using ANCOVA. Serum levels of triglycerides, total cholesterol, GOT, GPT, gamma-GTP, total bilirubin, and conjugated bilirubin were associated with the blood concentration of PCB adjusting for sex, age, drinking habit, smoking habit and body mass index (BMI). Because the distribution of the serum levels was strongly skewed to the right except that of serum concentration of total cholesterol, they were log transformed to approximate to the Normal distribution. The association between age and the blood concentration of PCB was significant (P < 0.001), although the associations of sex, drinking habit, smoking habit and BMI to the blood concentration of PCB were not significant. With the adjustment for sex, age, drinking habit, smoking habit and BMI, the serum concentrations of triglycerides and total cholesterol were significantly associated with the blood PCB level expressed by loge (blood concentration of PCB in ppb-1) (P = 0.02 and P < 0.001, respectively). The associations of serum levels of GOT, GPT, gamma-GTP, total bilirubin and conjugated bilirubin to the PCB level were not significant. The results of this study suggests the need of careful observation on the serum lipids of Yusho patients, especially those with high concentration of blood PCB, because the serum concentrations of total cholesterol and triglycerides are prominent risk factors of heart diseases.

Adult↗
PubMed1999

[A case of primary transitional cell carcinoma of the prostate].

We report a rare case of primary transitional cell carcinoma of the prostate. A 66-year-old man was referred to our hospital with the chief complaints of pollakisuria and residual urine sensation on January 21, 1998. Under a preoperative diagnosis of benign prostatic hyperplasia, transurethral resection of the prostate was performed. Histopathological examination revealed grade 3 transitional cell carcinoma. Then the transrectal needle biopsy of the prostate and random biopsy of the urinary bladder were performed. Since no metastatic tumors or tumor cells were detected in either the prostate or urinary bladder or any other organs, this patient was diagnosed with primary transitional cell carcinoma of the prostate. Three courses of adjuvant chemotherapy (M-VAC) were performed, and tumor recurrence was not recognized 9 months after the operation. This is the 35th case of primary transitional cell carcinoma of the prostate in the Japanese literature.

Aged↗
PubMed1998

In vitro dissociation of antifungal efficacy and toxicity for amphotericin B-loaded poly(ethylene oxide)-block-poly(beta benzyl L aspartate) micelles.

Amphotericin B (AmB) is a membrane-active drug used frequently for the treatment of systemic fungal diseases. Limitations for the use of AmB include poor water solubility and potential for serious systemic toxicities. Recently, it has been demonstrated that the aggregation state of AmB is a determinant factor for toxicity. To increase its therapeutic index, AmB has been solubilized in micelles based on poly(ethylene oxide)-block-poly(beta-benzyl-l-aspartate) (PEO-block-PBLA), using a dialysis method of drug loading. The aggregation state of AmB has been investigated by electronic absorption spectroscopy. AmB loaded in PEO-block-PBLA micelles is non-hemolytic for concentrations up to 15 microgram/ml. AmB as Fungizone(R) initiates hemolysis at 1.0 microgram/ml. The onset of hemolysis correlates with the respective critical aggregation concentrations (CACs) of AmB. The antifungal activity of the AmB-loaded PEO-block-PBLA micelles is four to eight times higher than Fungizone(R) in terms of minimal inhibitory concentrations (MICs). PEO-block-PBLA has no antifungal activity for concentrations up to 200 microgram/ml. The basis for the increase in antifungal activity of AmB-loaded PEO-block-PBLA micelles is unclear, but may be related to a stabilizing effect of the polymeric micelles against auto-oxidation of the AmB heptaene moiety or alternatively, an enhancement in membrane perturbation of fungal cells.

Amphotericin B↗