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Biomedical subjects

H Itokawa

Publications and source records attributed to H Itokawa.

At least 19 recordsLinked to original sources
PubMed2006

Astrocytes co-express aquaporin-1, -4, and vascular endothelial growth factor in brain edema tissue associated with brain contusion.

INTRODUCTION: Brain edema may be life threatening. The mechanisms underlying the development of traumatic brain edema are still unclear; however, mixed mechanisms including vasogenic, ischemic, and neurotoxic types of edema may be contributors. Recent studies indicate that astrocytes, aquaporins (AQPs; a protein family of water channels), and vascular endothelial growth factor (VEGF) may have important roles in the formation and resolution of brain edema. We studied the expression of AQPs and VEGF in the edematous brain. METHODS: We investigated the expression of AQP1, AQP4, and vascular endothelial growth factor (VEGF) in contusional brain tissue surgically obtained from 6 patients. Glial fibrillary acidic protein (GFAP) was also stained to detect astrocytes and to clarify the location of those proteins. The specimens received immunohistological staining and 3-color immunofluorescent staining, and were observed using confocal laser scanning microscopy. RESULTS: AQP1, AQP4, and VEGF were co-expressed in GFAP-positive astrocytes. AQP1 and AQP4 were expressed strongly in astrocytic end-feet. The astrocytes were located in the edematous tissue, and some cells surrounded cerebral capillaries. CONCLUSION: Our results suggest that AQP1, AQP4, and VEGF are induced in astrocytes located in and surrounding edematous tissue. Those astrocytes may regulate the water in- and out-flow in the injured tissue.

Adolescent↗
PubMed2003

Very early expression of vascular endothelial growth factor in brain oedema tissue associated with brain contusion.

BACKGROUND: Brain oedema associated with cerebral contusion can be life-threatening. Mechanisms of the development of brain oedema are still unclear. METHOD: We investigated the expression of vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 (KDR/Flk-1) in the contusional brain tissue obtained during neurosurgery from 5 patients. FINDINGS: VEGF is expressed in some but not all the astrocytes, and KDR/Flk-1 is expressed in vascular endothelial cells in the con-tusional tissue as early as 3 hours after onset. CONCLUSION: The results suggested that the VEGF is induced in the contusional tissue in the very early period after onset, and that it increases capillary permeability via KDR/Flk-1 resulting in vasogenic type brain oedema.

Adolescent↗
PubMed2001

Cytotoxic activity of Typhonium flagelliforme (Araceae).

The plant Typhonium flagelliforme (Araceae), commonly known as the 'rodent tuber', is often included as an essential ingredient in various herbal remedies recommended for cancer therapies in Malaysia. Various extracts prepared from either the roots, tubers, stems or leaves were tested for cytotoxic activity on murine P388 leukaemia cells using the MTT assay method. Both the chloroform (IC50 = 6.0 microg/mL) and hexane (IC50 = 15.0 microg/mL) extract from the 'roots and tubers' exhibited weak cytotoxic activity. The hexane extract (IC50 = 65.0 microg/mL) from the 'stems and leaves' exhibited weaker cytotoxic activity than the chloroform extract (IC50 = 8.0 microg/mL). Although the juice extract from the 'roots and tubers' is frequently consumed for cancer treatment, it exhibited poor cytotoxic activity. Further analysis using an amino acid analyser revealed that the juice extract contained a high concentration of arginine (0.874%). A high tryptophan content (0.800%) was confirmed by NMR and HPLC analysis.

Amino Acids↗
PubMed2001

Cyclolinopeptides F-I, cyclic peptides from linseed.

Four cyclic peptides, cyclolinopeptides F-I, were isolated from seeds of Linum usitatissimum. Their structures were elucidated by extensive 2D NMR spectroscopic methods and by chemical degradation. Further, their immunosuppressive activity is examined.

Amino Acid Sequence↗
PubMed2001

Nitrous oxide production in high-loading biological nitrogen removal process under low COD/N ratio condition.

Effects of influent COD/N ratio on N2O emission from a biological nitrogen removal process with intermittent aeration, supplied with high-strength wastewater, were investigated with laboratory-scale bioreactors. Furthermore, the mechanism of N2O production in the bioreactor supplied with low COD/N ratio wastewater was studied using 15N tracer method, measuring of reduction rates in denitrification pathway, and conducting batch experiments under denitrifying condition. In steady-state operation, 20-30% of influent nitrogen was emitted as N2O in the bioreactors with influent COD/N ratio less than 3.5. A 15N tracer study showed that this N2O originated from denitrification in anoxic phase. However, N2O reduction capacity of denitrifiers was always larger than NO3(-)-N or NO2(-)-N reduction capacity. It was suggested that a high N2O emission rate under low COD/N ratio operations was mainly due to endogenous denitrification with NO2(-)-N in the later part of anoxic phase. This NO2(-)-N build-up was attributed to the difference between NO3(-)-N and NO2(-)-N reduction capacities, which was the feature observed only in low COD/N ratio operations.

Bioreactors↗
PubMed2001

Anti-HIV and cytotoxic activities of Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine/chalcone as co-ligand.

Ru(II)/Ru(III) polypyridyl complexes containing 2,6-(2'-benzimidazolyl)-pyridine or chalcone as co-ligands were synthesized and characterized previously (Mishra, L.; Sinha, R. Indian J. Chem., Sec. A 2001, in press. Mishra, L.; Sinha, R. Indian J. Chem., Sec. A, 39A, 2000, 1131). Their interaction with aqueous buffered calf thymus DNA was measured. (Novakova, O.; Kasparkova, J.; Vrana, O.; van Vliet, P. M., Reedijk, J.; Brabec, V., Biochem. 34, 1995, 12369 and these results prompted additional screening for anti-HIV (human immunodeficiency virus) activity against DNA replication in H9 lymphocytes and cytotoxic activity against eight tumor cell lines. The most active compounds were 17 in the former assay (EC(50) < 0.1 microg/mL and TI > 23.1) and 3, 8, 10, and 14 in the latter assay, especially selectively against the 1A9 ovarian cancer cell line (IC(50) = 4.1, 3.8, 3.6, and 2.5 microg/mL, respectively).

Anti-HIV Agents↗
PubMed2000

4-Aza-2,3-dehydro-4-deoxypodophyllotoxins: simple aza-podophyllotoxin analogues possessing potent cytotoxicity.

4-Aza-2,3-dehydro-4-deoxypodophyllotoxin analogues 3a-n were synthesized through quinolines 2a-n. Comparison of their cytotoxicity against P-388 leukemia cells revealed that the steric effects of the ring B substituents on the activity are greater than the electronic effects, while the presence of a methoxy group on the ring E is not essential to exhibit potent cytotoxicity. Analogues 3a and 3b proved to be more than twice as cytotoxic as natural podophyllotoxin (1).

Antineoplastic Agents, Phytogenic↗
PubMed2000

Steroidal saponins from the leaves of Cestrum sendtenerianum.

Five steroidal saponins were isolated from the EtOH extract of Cestrium sendtenerianum (Solanaceae), as confirmed by detailed analysis of their 1H, 13C, and two-dimensional NMR spectral data, and by the results of hydrolytic cleavage. The saponins were revealed to contain three hydroxyl groups at the C-1beta, C-2alpha, and C-3beta positions in the spirostanol skeleton, and to bear a di- or triglycoside at C-3 as the common structural features. One of the compounds, a spirostanol triglycoside, showed weak cytotoxic activity on HL-60 human promyelocytic leukemia cells, with an IC50 value of 7.7 microg/ml.

Carbohydrate Conformation↗
PubMed1999

[Antitumor compounds isolated from higher plants].

A lot of anticancer agents have been isolated from natural sources, especially from microorganisms and plants. However, there is no special type of compounds for cancer therapy. Various types of substances are effective for various types of cancers and tumors: for instance, alkaloids, lignans, terpenes and steroids, etc. In this report, the authors will describe especially about higher plants.

Alkaloids↗
PubMed1998

Cytotoxic quassinoids from Simaba cedron.

Four new quassinoids, cedronolactones A-D (1-4), together with nine known compounds, simalikalactone D (5), chaparrinone (6), chaparrin (7), glaucarubolone (8), glaucarubol (9), samaderine Z (10), guanepolide (11), ailanquassin A (12), and polyandrol (13), were isolated from the wood of Simaba cedron. The chemical structures of 1-4 were elucidated on the basis of their chemical and spectral properties. Cedronolactone A (1) was shown to exhibit a significant in vitro cytotoxicity (IC50 0.0074 microg/mL) against P-388 cells.

Alkaloids↗
PubMed1998

Triterpenoid saponin from Vaccaria segetalis.

A new triterpenoid saponin, vaccaroid B, has been isolated from the seeds of Vaccaria segetalis and its structure was elucidated to be 3beta-hydroxyolean-12-en-23, 28-dioic acid-28-O-beta-D-glucopyranosyl-(1-->3)- beta-D-glucopyranosyl-(1-->6)-[6- O-(3-hydroxy-3-methylglutaryl)-beta-D-glucopyranosyl-(1-->2)]- beta-D-glucopyranoside by spectroscopic methods.

Carbohydrate Conformation↗
PubMed1998

Structure-cytotoxic activity relationship for the toad poison bufadienolides.

The toad poison bufadienolides including natural and derivatized compounds were tested for their cytotoxic effects on primary liver carcinoma cells PLC/PRF/5 and their structure-cytotoxic activity relationships were studied. For this study, a ligand-binding model was developed by using a pharmacophore mapping program, Distance Comparisons (DISCO). The structural features that are common to the 3D structures of active bufadienolides were identified to provide approach to a 3D QSAR method by using Comparative Molecular Field Analysis (CoMFA) study and to correlate the steric and electrostatic fields of the molecules to their activities. A valuable model which enables prediction of their activities was obtained from the CoMFA analysis, which may be employed for the drug designs of new bufadienolide analogues.

Antineoplastic Agents↗
PubMed1998

[A case of dural arteriovenous fistula in the transverse and sigmoid sinus which developed over five years].

We report a case of dural arteriovenous fistula (dAVF) of the transverse and sigmoid sinus which developed over five years. The patient was a 64-year-old man, who had a history of congestive heart failure and transient ischemic attack (TIA). No abnormal lesions were detected in the cerebral angiograms five years prior to the time the etiology of his TIA was investigated. He suddenly suffered from left hemiparesis and the CT scan showed right parietal subcortical hemorrhage. Right carotid angiogram demonstrated dAVF of the transverse and sigmoid sinus supplied by the right occipital and ascending pharyngeal arteries. We thought the reason for the subcortical hemorrhage in this patient was due to the disturbance of venous return in the right cerebral hemisphere. We underwent direct embolization of the right transverse sinus by interlocking detachable coils. Postoperative cerebral angiograms demonstrated the disappearance of dAVF and he was discharged. Whether dAVF is a congenital anomaly or not, has been controversial. Since the dAVF in this case had newly developed over five years, it is suggested that dAVF is an acquired lesion.

Arteriovenous Fistula↗
PubMed1997

Ester-type cephalotaxus alkaloids from Cephalotaxus harringtonia var. drupacea.

Three alkaloids, neoharringtonine, homoneoharringtonine and 3'S-hydroxyneoharringtonine, were isolated from the leaves and stems of Cephalotaxus harringtonia var. drupacea. Their structures were established by spectroscopic methods, including two-dimensional NMR and CD spectra, and their antileukaemic activity was evaluated using P-388 leukaemia cells.

Alkaloids↗
PubMed1997

Cytotoxic triterpenes from Cleome africana.

Eighteen dammarane-type triterpenes were obtained from the whole plant of Cleome africana by means of cytotoxic bioassay-directed fractionation. Twelve of them were novel compounds whose structures were elucidated by various spectroscopic methods.

Animals↗
PubMed1997

Cyclic octapeptides from Stellaria dichotoma var. lanceolata.

Two new cyclic octapeptides, dichotomin H, cyclo(-Ala-Pro-Thr-Phe-Tyr-P ro-Leu-Ile-), and dichotomin I, cyclo(-Val-Pro-Thr-Phe-Tyr-Pro-Leu-Ile-) have been isolated from the roots of Stellaria dichotoma L. var lanceolata Bge., and their structures were elucidated by extensive two-dimensional NMR methods and chemical degradation.

Amino Acid Sequence↗