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Biomedical subjects

H Takayama

Publications and source records attributed to H Takayama.

At least 37 records · Page 2Linked to original sources
PubMed2001

Methyl chanofruticosinates from leaves of Kopsia flavida Blume.

Three new indole alkaloids with methyl chanofruticosinates skeletal system, viz., methyl 12-methoxy-N1-decarbomethoxychanofruticosinate, methyl 12-methoxychanofruticosinate and methyl 11,12-dimethoxychanofruticosinate, in addition to methyl 11,12-methylenedioxy-N1-decarbomethoxychanofruticosinate, have been isolated from the leaves of Kopsia flavida Blume. The structures of these three new indole alkaloids were assigned by NMR spectral data using various 2D-techniques.

Alkaloids↗
PubMed2001

Artoindonesianin L, a new prenylated flavone with cytotoxic activity from Artocarpus rotunda.

A new prenylated flavone, named artoindonesianin L (1), was isolated from Artocarpus rotunda (Hout) Panzer (Moraceae). Its structure was elucidated as on the basis of spectroscopic evidence. Along with this new compound, four known phenolic compounds were also isolated from this plant and identified as artonins M (2) and E (3), cycloartobiloxanthone (4) and artonin O (5). All these compounds showed significant cytotoxicity against murine P388 leukemia cells.

Animals↗
PubMed2001

Highly potent cell differentiation-inducing analogues of 1alpha,25-dihydroxyvitamin D3: synthesis and biological activity of 2-methyl-1,25-dihydroxyvitamin D3 with side-chain modifications.

Eight 2-methyl substituted analogues of 20-epi-22R-methyl-1alpha,25-dihydroxyvitamin D3 (5) and 20-epi-24,26,27-trihomo-22-oxa-1alpha,25-dihydroxyvitamin D3 (6: KH-1060) were convergently synthesized. Preparation of the CD-ring portions with modified side chains of 5 and 6, followed by palladium-catalyzed cross-coupling with the A-ring enyne synthons (20a-d), (3S,4S,5R)-, (3S,4R,5R)-, (3S,4S,5S)- and (3R,4R,5S)-3,5-bis[(tert-butyldimethylsilyl)oxy]-4-methyloct-1-en-7-yne, afforded two sets of four A-ring stereoisomers of 20-epi-2,22-dimethyl-1,25-dihydroxyvitamin D3 (7a-d) and 20-epi-24,26,27-trihomo-2-methyl-22-oxa-1,25-dihydroxyvitamin D3 (8a-d). The biological profiles of the hybrid analogues were assessed in terms of affinity for vitamin D receptor (VDR) and HL-60 cell differentiation-inducing activity in comparison with the natural hormone. The combined modifications of the A-ring at the 2-position and the side chain yielded analogues with high potency.

Antineoplastic Agents↗
PubMed2001

Synthesis and biological evaluation of all A-ring stereoisomers of 5,6-trans-2-methyl-1,25-dihydroxyvitamin D(3) and their 20-epimers: possible binding modes of potent A-ring analogues to vitamin D receptor.

BACKGROUND: The secosteroid 1 alpha,25-dihydroxyvitamin D(3) (1) has a wide variety of biological activities, which makes it a promising therapeutic agent for the treatment of cancer, psoriasis and osteoporosis. Insight into the structure-activity relationships of the A-ring of 1 is still needed to assist the development of more potent and selective analogues as candidate chemotherapeutic agents, as well as to define the molecular mode of action. RESULTS: All possible A-ring stereoisomers of 5,6-trans-2-methyl-1,25-dihydroxyvitamin D(3) (6a-h) and their 20-epimers (7a-h) were designed and efficiently synthesized. The dependence of the affinities for vitamin D receptor (VDR) and vitamin D binding protein (DBP), as well as the HL-60 cell differentiation-inducing activity, upon the stereochemistry of the A-ring and at C20 in the side chain was evaluated. CONCLUSIONS: The binding affinities and potency of the 5,6-trans and 5,6-cis analogues were enhanced by a 2-methyl substituent in a certain orientation. Molecular docking studies based upon the X-ray crystal structure of VDR suggested that the axial 2-methyl group would be accommodated in a pocket surrounded by hydrophobic amino acid residues in the ligand binding domain, resulting in enhanced interaction.

Animals↗
PubMed2001

Isolation and bioactivities of constitutents of the roots of Garcinia atroviridis.

Two new prenylated compounds, the benzoquinone atrovirinone (1) and the depsidone atrovirisidone (2), were isolated from the roots of Garcinia atroviridis. Their structures were determined on the basis of the analysis of spectroscopic data. While compound 2 showed some cytotoxicity against HeLa cells, both compounds 1 and 2 were only mildly inhibitory toward Bacillus cereus and Staphylococcus aureus.

Adolescent↗
PubMed2001

Effect of alpha-tocopherol on hepatocarcinogenesis in transforming growth factor-alpha (TGF-alpha) transgenic mice treated with diethylnitrosamine.

To examine the potentially chemopreventive effects of alpha-tocopherol on hepatocarcinogenesis, we fed the transgenic mice line MT42, which overexpresses transforming growth factor-alpha (TGF-alpha) and which has been established as having a high incidence of liver tumor, with different concentrations of alpha-tocopherol and examined the hepatic tumorigenesis of these mice. At 3 weeks of age, MT42 male mice received a single intraperitoneal injection of diethylnitrosamine (DEN), 5 mg/kg body weight, to initiate the formation of liver tumors. The mice were divided into three groups: group A, control diet (20 mg/kg of alpha-tocopherylacetate); group B, deficient diet (less than 1 mg/kg); group C, supplemented diet (500 mg/kg). Neoplastic change was determined at 40 weeks of age. The incidence of adenomas (p < 0.05), the maximum tumor size (p < 0.01), the mean relative liver weight (p < 0.01), and the proliferating cell nuclear antigen (PCNA) labeling indices of the non-tumor sites (p < 0.01) of group B were significantly higher than those of group C. No toxic effects of alpha-tocopherol were found. Alpha-tocopherol-deficient diet accelerated the hepatocarcinogenesis of TGF-alpha transgenic mice treated with DEN. At best, these data demonstrate that alpha-tocopherol-deficiency is not beneficial for prevention of hepatocarcinogenesis in this model. Alpha-tocopherol may be useful for the chemoprevention for liver cancer.

Alkylating Agents↗
PubMed2001

Changes of serum melatonin level and its relationship to feto-placental unit during pregnancy.

Serum melatonin concentrations were studied in normal pregnant women and in women with several types of pathologic pregnancies, e.g., twins, preeclampsia or intrauterine growth retardation (IUGR). Blood samples were collected from the maternal antecubital vein at 14:00 hr (daytime) and 02:00 hr (nighttime) during pregnancy, and also from the umbilical vein and artery immediately after delivery. Serum melatonin concentrations were measured by radioimmunoassay. Daytime serum melatonin levels in normal (single fetus; singleton) pregnancies were low. While the levels showed an increasing tendency toward the end of pregnancy, no statistically significant changes occurred. On the other hand, the nighttime serum melatonin levels increased after 24 weeks of gestation, with significantly (P < 0.01) high levels after 32 weeks; these values decreased to non-pregnant levels on the 2nd day of puerperium. Nighttime serum melatonin levels were significantly (P < 0.05) higher in twin pregnancies after 28 weeks of gestation than in singleton pregnancies, whereas the patients with severe preeclampsia showed significantly (P < 0.05) lower serum melatonin levels than the mild preeclampsia or the normal pregnant women after 32 weeks of gestation. Melatonin concentrations in umbilical vessels showed a higher tendency in neonates who were born during at night compared with the other neonates; moreover, those in the umbilical artery were generally higher than those in the umbilical vein. The present results indicate that in humans, the maternal serum melatonin levels show a diurnal rhythm, which increases until the end of pregnancy, reflecting some pathologic states of the feto-placental unit. Fetuses may produce melatonin with a circadian rhythm.

Adult↗
PubMed2001

Fas gene mutations in prostatic intraepithelial neoplasia and concurrent carcinoma: analysis of laser capture microdissected specimens.

Fas (Apo-1/CD95) is a cell-surface receptor involved in cell death signaling through binding of Fas ligand. Mutations of the Fas gene might be involved in proliferative diseases of the prostate by prolongation of programmed cell death of prostatic epithelial cells. Using the laser capture microdissection method, Fas gene mutations were examined on genomic DNA extracted from lesions with high-grade prostatic intraepithelial neoplasia (HGPIN), a possible precursor of prostatic cancer (PCA), and from PCA. A total of 193 lesions, 111 with HGPIN, 55 with PCA, and 27 benign glands, were microdissected from 27 patients with PCA. Polymerase chain reaction-amplified products were directly sequenced. Loss of heterozygosity (LOH) was examined at four sites of known polymorphisms. Fas gene mutations were detected in HGPIN: 4 of 27 (14.8%) cases or 4 of 111 (3.6%) lesions. All were point mutations: three missense and one nonsense in the death domain. Benign proliferative glands adjoining HGPIN and/or PCA, and PCA never showed mutations. LOH was found in 31.3% of PCA and 25% of HGPIN lesions, but was never found in benign glands. Exclusive occurrence of Fas mutations in HGPIN might underlie the development of these lesions. Occasional findings of LOH in HGPIN and PCA suggested that genetic instability might occur during the early phase of prostatic carcinogenesis.

Alleles↗
PubMed2001

Ulcerative proctitis, rectal prolapse, and intestinal pseudo-obstruction in transgenic mice overexpressing hepatocyte growth factor/scatter factor.

Hepatocyte growth factor/scatter factor (HGF/SF) can stimulate growth of gastrointestinal epithelial cells in vitro; however, the physiological role of HGF/SF in the digestive tract is poorly understood. To elucidate this in vivo function, mice were analyzed in which an HGF/SF transgene was overexpressed throughout the digestive tract. Nearly a third of all HGF/SF transgenic mice in this study (28 of 87) died by 6 months of age as a result of sporadic intestinal obstruction of unknown etiology. Enteric ganglia were not overtly affected, indicating that the pathogenesis of this intestinal lesion was different from that operating in Hirschsprung's disease. Transgenic mice also exhibited a rectal inflammatory bowel disease (IBD) with a high incidence of anorectal prolapse. Expression of interleukin-2 was decreased in the transgenic colon, indicating that HGF/SF may influence regulation of the local intestinal immune system within the colon. These results suggest that HGF/SF plays an important role in the development of gastrointestinal paresis and chronic intestinal inflammation. HGF/SF transgenic mice may represent a useful model for the study of molecular mechanisms associated with a subset of IBD and intestinal pseudo-obstruction. Moreover, our data identify previously unappreciated side effects that may be encountered when using HGF/SF as a therapeutic agent.

Animals↗
PubMed2001

Zinc supplementation enhances the response to interferon therapy in patients with chronic hepatitis C.

We evaluated the synergistic effect of zinc supplementation on the response to interferon (IFN) therapy in patients with intractable chronic hepatitis C in a pilot study using natural IFN-alpha with or without zinc. No clinical differences were observed between patients treated with IFN alone (n=40) and IFN with polaprezinc (IFN + Zn, n=35). All patients were positive for HCV genotype Ib and had more than 105 copies of the virus/mL serum. Ten million units of natural IFN-alpha was administered daily for 4 weeks followed by the same dose every other day for 20 weeks. In the IFN + Zn group, patients received an additional dose of 150 mg/day polaprezinc orally throughout the 24-week IFN course. No additional side-effects of polaprezinc were noted but four out of 40 IFN alone treatment and three out of 35 IFN + Zn group withdrew because of side-effects. Complete response (CR) was defined as negative HCV RNA in the serum on PCR and normal aminotransferase level 6 months after therapy. Incomplete response (IR) was normal liver enzyme and positive serum HCV RNA. Both of them were evaluated at the 6 months after the completion of the treatment. Patients with higher levels of serum HCV (more than 5 x 105 copies/mL) had little response in both treatment groups. Patients with moderate amount of HCV (105 to 4.99 x 105/mL) showed high response rates in combination group (CR: 11/27, 40.7%; CR + IR 15/27, 64.3%), better than IFN alone (CR: 2/15, 18.2%; CR + IR: 2/15, 18.2%). Serum zinc levels were higher in patients with IFN + Zn group than in the IFN group. Our results indicate that zinc supplementation enhances the response to interferon therapy in patients with intractable chronic hepatitis C.

Adult↗
PubMed2001

Immunohistochemical detection of the c-met proto-oncogene product in the congenital melanocytic nevus of an infant with neurocutaneous melanosis.

Transgenic mice overexpressing hepatocyte growth factor/scatter factor (HGF/SF) demonstrate extensive pigmented nevi in both skin and leptomeninges of the central nervous system resembling human neurocutaneous melanosis. We immunohistochemically detected HGF/SF receptor, Met, in a congenital nevus of an infant with neurocutaneous melanosis, indicating that deregulation of HGF/SF-Met signaling in the critical period of development may lead to this fatal syndrome.

Animals↗
PubMed2001

Induction of manganese superoxide dismutase by tumour necrosis factor-alpha in human endometrial stromal cells.

The present study was undertaken to investigate the effect of tumour necrosis factor-alpha (TNFalpha) on superoxide dismutase (SOD) expression in human endometrial stromal cells (ESC) and to determine whether there is a difference in responsiveness to TNFalpha between ESC and decidualized ESC. TNFalpha increased manganese-SOD (Mn-SOD) mRNA level and Mn-SOD activity in a dose-dependent manner in ESC. The concentration of TNFalpha required for an effect was lower for decidualized ESC than for non-decidualized ESC. TNFalpha had no effect on copper-zinc-SOD (Cu,Zn-SOD) expression in either type of cell. Incubation of ESC with actinomycin D, an RNA synthesis inhibitor, blocked TNFalpha-induced Mn-SOD mRNA expression, but cycloheximide, a protein synthesis inhibitor, had no effect. H7, an inhibitor of protein kinase C (PKC), also inhibited TNFalpha-stimulated Mn-SOD mRNA expression in both types of cells. These findings suggest that TNFalpha-induced Mn-SOD expression is regulated at the transcription level and mediated by PKC-dependent phosphorylation and that de-novo protein synthesis is not required for the TNFalpha effect. In summary, TNFalpha induces Mn-SOD expression in human ESC. This phenomenon may be important for protection of ESC from cytokine-mediated oxidative stress.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2001

Evidence for a Schiff base formation of peptides derived from RecA with single-stranded oligonucleotides containing 5-formyl-2'-deoxyuridine.

We report some evidence for a Schiff base formation of 5-formyl-2'-deoxyuridine containing oligonucleotides with oligopeptide derived from the DNA binding site of RecA protein. We have demonstrated that cross-linked products were successfully detected by lowering the peptide concentrations. This is probably due to the reduced formation of large aggregates.

Amino Acid Sequence↗
PubMed2001

Regulation and role of vascular endothelial growth factor in the corpus luteum during mid-pregnancy in rats.

The present study was undertaken to investigate the role of vascular endothelial growth factor (VEGF) in luteal angiogenesis and the regulation of VEGF in the corpus luteum (CL) during mid-pregnancy in rats. Protein concentrations and mRNA levels of VEGF in the CL significantly increased from Day 9 to Day 12 and remained at the same level as Day 12 until Day 15. To study whether estradiol is involved in VEGF expression between Day 12 and Day 15, rats undergoing hypophysectomy-hysterectomy on Day 12 were treated with estradiol until Day 15. Protein concentrations and mRNA levels of VEGF in the CL were significantly decreased by hypophysectomy-hysterectomy, and this inhibitory effect was completely reversed by estradiol treatment. Changes in vascular density in the CL were parallel to those in VEGF expression. To examine whether the effect of estradiol is mediated by VEGF, anti-VEGF antibody was administered to hypophysectomized-hysterectomized rats simultaneously with estradiol. The recovery in the vascular density, CL weight, and serum progesterone concentration caused by estradiol was significantly inhibited by the anti-VEGF antibody treatment. In conclusion, the present study has demonstrated that VEGF contributes to luteal angiogenesis, CL development, and progesterone production during mid-pregnancy in rats and that luteal VEGF expression is increased by estradiol.

Animals↗
PubMed2001

Longitudinal changes of metabolites in frontal lobes after hemorrhagic stroke of basal ganglia: a proton magnetic resonance spectroscopy study.

BACKGROUND AND PURPOSE: We investigated serial metabolic changes in frontal lobes of patients with deep intracerebral hemorrhage (ICH) to examine the correlation between N-acetylaspartate (NAA) and degree of motor impairment or clinical outcome. METHODS: - Twenty patients with deep ICH were examined with proton magnetic resonance spectroscopy with the application of a multivoxel method (1 voxel=10x10x20 mm; 64 voxels). NAA/creatine ratios in the white matter of the primary motor and premotor areas on both sides were measured sequentially: within 48 hours, at 2 weeks, and 1 month after onset. The National Institutes of Health Stroke Scale and Barthel Index for disability were measured for each patient. RESULTS: - In the primary motor area on the affected side, where the hematoma did not extend, the NAA/creatine ratio decreased sequentially. At 48 hours and 2 weeks after onset, a negative correlation was detected between NAA/creatine and hematoma volume, but there was no correlation 1 month later. At 2 weeks, NAA/creatine correlated negatively with motor impairment (r=-0.750), and there was a significant correlation with clinical outcome as early as 2 weeks after onset (r=0.954). These sequential changes of NAA/creatine varied according to patients' long-term clinical outcome. Patients with poor outcome demonstrated notable reduction of NAA/creatine over the bilateral frontal lobes. CONCLUSIONS: - The delayed gradual reduction of NAA/creatine ratio in the frontal lobes correlates with motor deficit and clinical outcome after deep ICH, suggesting that the neural networks in the frontal lobe could be important for recovery.

Aged↗
PubMed2000

Structure-specific control of differentiation and apoptosis of human promyelocytic leukemia (HL-60) cells by A-ring diastereomers of 2-methyl-1alpha,25-dihydroxyvitamin D(3) and its 20-epimer.

1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) has been shown to modulate not only proliferation and differentiation but also apoptosis of malignant cells, indicating that it would be useful for the treatment of hyperproliferative diseases such as cancer and psoriasis. Little information is available concerning structural motifs of the 1alpha,25(OH)(2)D(3) molecule responsible for modulation of differentiation and apoptosis. We synthesized all possible A-ring diastereomers of the 2-methyl-1alpha,25(OH)(2)D(3) and its 20-epimer and evaluated their biological activities in human promyelocytic leukemia (HL-60) cells. Surprisingly, the potent analogues could be clearly divided into two groups: (i) those bearing the 1alpha- and 3beta-hydroxyl groups on the A-ring were potent inducers of differentiation and growth inhibitors of HL-60 cells and (ii) those bearing the 1beta-hydroxyl group together with either 3alpha- or 3beta-hydroxyl groups on the A-ring were potent stimulators of apoptosis in these cells. We have clearly identified for the first time the structural motifs on the basis of the stereochemistry of both hydroxyl groups at positions 1 and 3 of the A-ring of the 1alpha,25(OH)(2)D(3) molecule responsible for the induction of differentiation and apoptosis of HL-60 cells. These findings provide useful information not only for structure-function studies of 1alpha,25(OH)(2)D(3) analogues but also for the development of therapeutic agents for the treatment of leukemia and other cancers.

Apoptosis↗