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Biomedical subjects

N Kanzaki

Publications and source records attributed to N Kanzaki.

18 recordsLinked to original sources
PubMed2002

In situ study of partially crystallized Bioglass and hydroxylapatite in vitro bioactivity using atomic force microscopy.

The present work investigates, in situ, the in vitro bioactivity of partially crystallized 45S5 Bioglass (BG) as a function of immersion time in a simulated body fluid (SBF) using atomic force microscopy (AFM). The results obtained for the crystallized BG were compared to those of hydroxyapatite c- and a-faces. The calcium phosphate layer grows on the crystallized 45S5 B by multiple two-dimensional nucleation and fusion of these two-dimensional islands, which is essentially the same mode as for the hydroxyapatite c-face. The surface of the crystallized 45S5 BG was almost fully covered with a dense and compact calcium phosphate layer after 24 h. The calcium phosphate formation on the crystallized BG arises from a low surface energy of the surface layer and/or an effect of the layer to lower the resistance when the growth units of calcium phosphate incorporate into the growing island. These results indicate that the crystallized 45S5 BG is suitable to be used as a filler for polymeric matrix bioactive composites, as it maintains a high bioactivity associated with a stiffer behavior (as compared to standard BG).

Biocompatible Materials↗
PubMed2001

Calcium phosphate clusters.

The potential energy surfaces associated with [Ca3(PO4)2n clusters are analyzed in detail using ab initio calculations for n ranging from one to four. Considering separated clusters, energy criteria favor the so-called Posner's cluster Ca9(PO4)6, which is the core of the actual structural model of amorphous calcium phosphate. This is rationalized through the existence of a distinct CaO bonding pattern in this cluster. Considering aggregated clusters as a possible model for amorphous calcium phosphate, the aggregation of Ca3(PO4)2 clusters appears as an alternative to Posner's hypothesis.

Biocompatible Materials↗
PubMed2001

Ulcerative duodenitis accompanying ulcerative colitis.

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon of unknown etiology. There are varied manifestations in the natural course of UC. However, duodenum is not generally considered a target organ of UC. Here, we report two patients with steroid-responsive ulcerative duodenitis with colitis that was consistent with UC, but not with Crohn's disease. We also reviewed six cases of ulcerative duodenitis with UC. Duodenal lesion with UC may be a more common phenomenon, although infrequently clinically manifested under steroid therapy. Upper gastrointestinal tract inflammation in UC warrants further studies to ascertain whether the duodenum is a target organ in UC, especially in steroid-free conditions.

Adult↗
PubMed2001

Inhibitory effects of small-molecule CCR5 antagonists on human immunodeficiency virus type 1 envelope-mediated membrane fusion and viral replication.

We established a human immunodeficiency virus type 1 (HIV-1) envelope (Env)-mediated membrane fusion assay and examined the small-molecule CCR5 antagonist TAK-779 and its derivatives for their inhibitory effects on HIV-1 Env-mediated membrane fusion and viral replication. The membrane fusion assay is based on HIV-1 long terminal repeat-directed beta-D-galactosidase reporter gene expression in CD4- and CCR5-expressed HeLa (MAGI-CCR5) cells after cocultivation with effector 293T cells expressing HIV-1 Env. Inhibition of HIV-1 replication was also determined in MAGI-CCR5 cells infected with the corresponding cell-free HIV-1. TAK-779 effectively suppressed R5 HIV-1 (strain JR-FL) Env-mediated membrane fusion as well as viral replication. Its 50% inhibitory concentrations (IC(50)s) for membrane fusion and viral replication were 0.87 +/- 0.11 and 1.4 +/- 0.1 nM, respectively. These values corresponded well to the IC(50) for (125)I-RANTES (regulated on activation, T cell expressed, and secreted) binding to CCR5 (1.4 nM). The inhibitory effects of 18 TAK-779 derivatives on membrane fusion differed from one compound to another. However, there was a close correlation among their inhibitory effects on membrane fusion, viral replication, and RANTES binding. The correlation coefficient between their IC(50)s for membrane fusion and viral replication was 0.881. Furthermore, since this assay depends on Env expressed in the effector cells, it is also applicable to the evaluation of CXCR4 antagonists. These results indicate that the HIV-1 Env-mediated membrane fusion assay is a useful tool for the evaluation of entry inhibitors.

Amides↗
PubMed2000

Discovery of novel, potent, and selective small-molecule CCR5 antagonists as anti-HIV-1 agents: synthesis and biological evaluation of anilide derivatives with a quaternary ammonium moiety.

The search for new small-molecule CCR5 antagonists by high-throughput screening (HTS) of the Takeda chemical library using [(125)I]RANTES and CHO/CCR5 cells led to the discovery of lead compounds (A, B) with a quaternary ammonium or phosphonium moiety, which were synthesized to investigate new MCP-1 receptor antagonists. A series of novel anilide derivatives 1 with a quaternary ammonium moiety were designed, synthesized, and tested for their CCR5 antagonistic activity. Through the optimization of lead compounds, we have found N,N-dimethyl-N-[4-[[[2-(4-methylphenyl)-6, 7-dihydro-5H-benzocyclohepten-8-yl]carbonyl]amino]benzyl]tetrahydr o-2 H-pyran-4-aminium chloride (1r, TAK-779) as a highly potent and selective nonpeptide CCR5 antagonist with a IC(50) value of 1.4 nM in the binding assay. Compound 1r also inhibited the replication of macrophage (M)-tropic HIV-1 (Ba-L strain) in both MAGI-CCR5 cells and PBMCs with EC(50) values of 1.2 and 3.7 nM, respectively. The synthesis and structure-activity relationships of 1r and its related compounds are detailed.

Amides↗
PubMed2000

Mucin ball-producing extrahepatic bile duct carcinoma.

The characteristic features of surgically curable mucin-producing extrahepatic bile duct carcinoma (MPEBC) have not previously been elucidated. Three (6.5%) of 46 patients who underwent surgery in our department for bile duct carcinoma between 1986 and 1997 had MPEBC. Clinicopathological features, diagnostic procedures and operative methods for patients with MPEBC were investigated. Tumors in the bile duct were identified by cholangioscopy combined with cholangiography after removal of mucin balls. Tumors were located close to the hepatic confluence in these patients. Two patients underwent hepatic lobectomy together with caudate lobectomy while the other underwent resection of the hepatic confluence. Absence of residual tumors was confirmed histologically in these patients. All three patients remain alive without evidence of recurrence, 22-54 months after surgery. MPEBC is a curable disease. Accurate localization in the biliary tree is essential and can only be obtained after, i) removal of mucin balls, and ii) extensive diagnostic work-up including cholangiography, cholangioscopy and intraoperative pathological examination.

Adenocarcinoma, Mucinous↗
PubMed2000

[A patient with multiple pulmonary metastases from colonic cancer who survived for 5 years by effectual administration of 5'-DFUR].

The patient was a 69-year-old woman who had been diagnosed with a bowel obstruction due to colonic cancer, with simultaneous multiple pulmonary metastases. The primary lesion was resected and 5'-DFUR was administered for 2 years at an out-patient clinic. During those 2 years, there was no change in CEA value and the pulmonary lesions were fading on the roentogenograms. It then became doubtful whether the pulmonary shadows were real metastases or not, and 5'-DFUR administration was discontinued. After stopping the medication, her CEA value rose and the tumor shadows increased in intensity. 5'-DFUR was therefore re-administrated and her CEA value declined. Afterwards, a re-elevation in CEA value was seen, and low-dose FP therapy was added on an out-patient basis. Anti-cancer chemotherapy of 5'-DFUR (oral) and low-dose FP (i.v.) was contributed to her 5-year survival.

Administration, Oral↗
PubMed1999

A small-molecule, nonpeptide CCR5 antagonist with highly potent and selective anti-HIV-1 activity.

The beta-chemokine receptor CCR5 is considered to be an attractive target for inhibition of macrophage-tropic (CCR5-using or R5) HIV-1 replication because individuals having a nonfunctional receptor (a homozygous 32-bp deletion in the CCR5 coding region) are apparently normal but resistant to infection with R5 HIV-1. In this study, we found that TAK-779, a nonpeptide compound with a small molecular weight (Mr 531.13), antagonized the binding of RANTES (regulated on activation, normal T cell expressed and secreted) to CCR5-expressing Chinese hamster ovary cells and blocked CCR5-mediated Ca2+ signaling at nanomolar concentrations. The inhibition of beta-chemokine receptors by TAK-779 appeared to be specific to CCR5 because the compound antagonized CCR2b to a lesser extent but did not affect CCR1, CCR3, or CCR4. Consequently, TAK-779 displayed highly potent and selective inhibition of R5 HIV-1 replication without showing any cytotoxicity to the host cells. The compound inhibited the replication of R5 HIV-1 clinical isolates as well as a laboratory strain at a concentration of 1.6-3.7 nM in peripheral blood mononuclear cells, though it was totally inactive against T-cell line-tropic (CXCR4-using or X4) HIV-1.

Amides↗
PubMed1999

[Home anti-cancer chemotherapy with continuous infusion of 5-FU combined with low-dose cisplatin injection via implantable venous port with portable balloon pump].

Home anti-cancer chemotherapy was performed for patients with advanced cancer of the digestive plantable venous port placed beneath the skin via the subclavian vein. 128 patients under 75 years old (enrolled: 6 patients with esophageal, 65 with gastric, 44 with colorectal, 5 with cholangio, 5 with pancreatic, one with hepatic and one with ileal cancer) were treated. Continuous intravenous infusion of 5-FU (300-400 mg/body/day) combined with low-dose injection of cisplatin (5 mg/body/day) was continued for 10 days, and repeated 3 times for 6 weeks. The response rate was 23.6% in 72 patients with valuation of tumor mass. In 83 patients for whom a tumor marker evaluation was also performed, an effect was seen in 30.1%. No severe side effects such as renal dysfunction were observed, and no special infusions were needed. Therefore, a quality of life was maintained in which bathing was possible and patients were released from the hospital. Hyperalimentation through the venous port, and palliation during the terminal stage, is easily accomplished. It is useful method for surgery, chemotherapy and palliative therapy in the treatment of cancer.

Aged↗
PubMed1998

Influence of age and gender on iodine-123 MIBG kinetics in normal lung.

UNLABELLED: Iodine-123 MIBG is a biochemical marker that can be used to monitor pulmonary norepinephrine (NE) metabolism. The purpose of this study was to characterize pulmonary I-123 MIBG kinetics in relation to age and gender. MATERIALS AND METHODS: Seventeen healthy volunteers and 14 patients with no cardiac or pulmonary disorders were included in this study (age range: 24 to 88 years, mean age 50.2 +/- 17.6 years; 16 males, 15 females). Planar images were obtained 15 min (early) and 3 h (delayed) after injection of I-123 MIBG (111 MBq). Pulmonary uptake of I-123 MIBG was quantified based on the lung-to-mediastinum ratio (LMR) on early and delayed images. The lung clearance rate (LCR) was calculated form both the early and delayed images. RESULTS: Both early and delayed LMR values increased slightly, although they showed no significant correlations with age. There was a significant inverse correlation between LCR and age (r = -0.57, p < 0.001). Neither LCR nor LMR differed significantly between male and female patients, but the mean age of the men was lower than that of the women. CONCLUSIONS: Pulmonary I-123 MIBG kinetics may reflect age-dependent changes in NE metabolism. The effects of age should be taken into account when assessing pulmonary NE metabolism with I-123 MIBG.

3-Iodobenzylguanidine↗
PubMed1997

Improved cardiac iodine-123 metaiodobenzylguanidine accumulation after drug therapy in a patient with Parkinson's disease.

A 72-year-old woman with Parkinson's disease and autonomic dysfunction underwent I-123 MIBG cardiac imaging to study sympathetic neuronal integrity. This revealed a defect in the infero-posterior wall. Tc-99m sestamibi myocardial perfusion imaging revealed no abnormalities. On follow-up I-123 MIBG SPECT, the defect was less prominent and the parkinsonian symptoms were ameliorated by drug therapy. Cardiac I-123 MIBG imaging may be a promising new method for evaluating drug therapy in patients with Parkinson's disease.

3-Iodobenzylguanidine↗
PubMed1989

High homology between 6-aminohexanoate-cyclic-dimer hydrolases of Flavobacterium and Pseudomonas strains.

The nucleotide sequences of the genes for 6-aminohexanoate-cyclic-dimer hydrolases of Flavobacterium sp. strain K172 (F-nylA) and Pseudomonas sp. NK87 (P-nylA), enzymes essential for the degradation of a by-product of the nylon-6 industry, were obtained by the dideoxynucleotide chain-termination method. A 1,479-base-pair open reading frame starting at a GTG and terminating at a TGA was found for the both of the genes. The P-nylA and F-nylA genes encoded polypeptides of 493 amino acids and had only 10 base substitutions in the coding region, which caused seven amino acid substitutions.

Amidohydrolases↗
PubMed1984

Construction of hybrid genes of 6-aminohexanoic acid-oligomer hydrolase and its analogous enzyme. Estimation of the intramolecular regions important for the enzyme evolution.

Hybrids were constructed of the genes for two homologous enzymes, 6-aminohexanoic acid-oligomer hydrolase (EII, one of the nylon oligomer degradation enzymes), and its probable evolutionary antecedent (EII'). The structural genes of EII (nylB) and EII' (nylB') have 88% similarity in their nucleotide sequences, an open frame encoding a peptide of 392 amino acids, conserved restriction sites, and in vitro recombination between these genes at the corresponding restriction sites generated genes directing various hybrid enzymes. In a comparison of the EII, EII', and the hybrid enzymes, we concluded that one or more of the four amino acid alterations that occurred in the intramolecular region (between amino acids 162-257) of EII' is essential to the adaptation of the enzyme to nylon oligomer degradation, and that its effect is enhanced 20-fold by one or more further alterations in the 258-380 region. Our results also suggest that this technique is useful for improving enzyme characteristics.

Amidohydrolases↗