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Biomedical subjects

S Tanabe

Publications and source records attributed to S Tanabe.

At least 145 records · Page 8Linked to original sources
PubMed1999

In vivo and in vitro evidence of blood-brain barrier transport of a novel cationic arginine-vasopressin fragment 4-9 analog.

The blood-brain barrier (BBB) transport and metabolism of a novel arginine-vasopressin fragment 4-9 [AVP(4-9), isoelectric point; (pI) = 9.2] analog, that is, cationic AVP(4-9) (C-AVP(4-9), PI = 9.8), were examined in vivo and in vitro. At 45 min after an i.v. administration to mice, the cerebrum-to-plasma concentration ratios of (35)S-labeled AVP(4-9) and (125)I-labeled C-AVP(4-9) were 0.103 and 0.330 ml/g cerebrum, respectively, and the BBB permeation clearances were 1.47 x 10(-4) and 3.10 x 10(-4) ml/min/g cerebrum, respectively. In the in vitro study using mouse brain capillary endothelial cells immortalized by SV40 infection (MBEC4), the acid-resistant binding values of (35)S-labeled AVP(4-9) and (125)I-labeled C-AVP(4-9) to MBEC4 at 120 min were 0.93 and 1.95 microliter/mg protein (as the cell/medium ratios), respectively. (35)S-labeled AVP(4-9) showed two-phase saturable acid-resistant binding, and its half-saturation constants (K(D)) were 3.8 nM (high affinity) and 45.7 microM (low affinity). (125)I-labeled C-AVP(4-9) showed single-phase saturable acid-resistant binding, with a K(D) value of 16.4 microM. The acid-resistant binding of (125)I-labeled C-AVP(4-9) was significantly dependent on temperature and medium osmolarity. The acid-resistant binding of (125)I-labeled C-AVP(4-9) was inhibited by dancylcadaverine, phenylarsine oxide (endocytosis inhibitors), 2,4-dinitrophenol (a metabolic inhibitor), and AVP(4-9), poly(L-lysine), and protamine (cationic substances), but not by poly(L-glutamic acid) (an anionic peptide) and the V(1) and V(2) vasopressin receptor antagonists. In addition, the conversion of C-AVP(4-9) to AVP(4-9) in the cerebral homogenate was confirmed by HPLC and mass spectrometry. The present results demonstrate that C-AVP(4-9) is transported through the BBB more effectively than AVP(4-9), via absorptive-mediated endocytosis, and that C-AVP(4-9) is converted to the neuroactive parent peptide, AVP(4-9), in the cerebrum.

Animals↗
PubMed1999

[Organochlorine pesticides and polychlorinated biphenyls in ambient air in the city of Gdańsk].

The concentrations of organochlorine pesticides such as DDTs, HCHs, CHLs, HCB and polychlorinated biphenyls (PCBs) were determined in ambient are samples collected in city of Gdańsk in 1991-1992 to understand concentrations, sources and seasonal distribution. Polyurethane foam plugs were used as adsorbents for collection of persitent organochlorines in ambient air samples. Identification and quantification of organochlorines were carried out using a capillary column gas chromatography and ECD (63Ni) detection. HCB, alpha-HCH, gamma-HCH, p,p'-DDT, o,p'-DDT, p,p'-DDE, o,p'-DDE, p,p'-DDD, o,p'-DDD and PCBs were detected in all samples, while the constituents of technical chlordan were absent in concentration above the detection limit of the method (trans-chlordane < 14 pg/m3, cis-chlordane < 8.1 pg/m3 and trans-nonachlor < 7.4 pg/m3). The concentrations of HCB and PCBs were depended on the air temperatures, hence their main source can be related to a process of degasing from the soil.

Air↗
PubMed1999

[Two regimens of combined 5'-deoxy-5-fluorouridine and cisplatin showing different dose intensities--investigation based on relative performances].

Patients with inoperable gastric cancer were given either of two regimens of combined 5'-deoxy-5-fluorouridine and cisplatin with different dose intensities. The results were compared based on ratios of the actual and the scheduled total doses of the regimens [relative performance (RP)]. The overall response rates and survival curves between the regimens showed no differences, but the incidences of severe adverse drug reactions was higher with regimen A, which had a higher dose intensity. Furthermore, survivals with regimen A were no different between the responding and non-responding patients, whereas the survivals of responding patients under regimen B were significantly longer than those of non-responding patients. Average RP were 0.87 with regimen A and 0.93 with regimen B. The mean RP of responding and non-responding patients were 0.94 and 0.84, respectively, with regimen A, and 0.99 and 0.89 with regimen B. Regarding survivals in both the RP = 1.0 and the RP < 1.0 groups, no difference was observed with regimen A. However, with regimen B, the RP = 1.0 group exhibited significantly better survival curves. Furthermore, survivals of the RP = 1.0 group under regimen B were much more favorable than in the RP = 1.0 group under regimen A. The above findings show that a regimen with an appropriate dose intensity has a favorable survival effect on patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

[Organochlorine pesticides and polychlorinated biphenyls in the Vistula river water].

The composition and loads of organochlorine pesticides (DDTs, HCBs, HCHs, CHLs) and polychlorinated biphenyls (PCBs) transported with the Vistula River waters to the Gulf of Gdansk in 1991-1992 has been determined. The method of organochlorine compounds measurement was capillary gas chromatography with ECD after adsorption of the analyte on Ambertlite XAD-2, resin and subsequent elution, clean-up and HPLC fraction of the extract. The concentrations of DDTs, HCBs, HCHs, CHLs and PCBs in the Vistula River water ranged between 120-840, 7.6-52, 1600-410,000, 8.1-57 and 120-300 pg/l, respectively. During 12 months period of the study the total load of DDTs, HCBz, HCHs, CHLs and PCBs transported with the Vistula River water to the Gulf of Gdańsk was assessed on 10.54, 0.73, 1377, 0.38 and 5.02 kg, respectively.

Environmental Pollutants↗
PubMed1998

Assay of nicotinamide deamidase activity using high-performance liquid chromatography.

A rapid, simple and reproducible method has been developed for the determination of nicotinamide deamidase activity using high-performance liquid chromatography (HPLC). Nicotinic acid (NA) liberated from nicotinamide (NAA) after a 15-min enzyme reaction was determined directly by HPLC without further separation steps. Both NA, the product, and NAA, the substrate were separated by reversed-phase ion-pair isocratic chromatography and detected at 261 nm. The present method could be applied to the measurement of deamidase activity in crude cell extracts prepared from several bacterial strains. The Michaelis constant of nicotinamide deamidase in Enterobacter agglomerans was 36 microM for NAA. This method is useful for the measurement of nicotinamide deamidase from various sources.

Bacteria↗
PubMed1998

A labile sulfur in trisulfide affects cytochrome P-450 dependent lipid peroxidation in rat liver microsomes.

The effects of trisulfide derivatives were studied on cytochrome P-450-dependent lipid peroxidation using rat liver microsomal systems. Cytochrome P-450-dependent lipid peroxidation was induced by carbon tetrachloride or tert-butylhydroperoxide and was evident by an increase in thiobarbituric acid-reactive substances (TBA-RS) and oxygen consumption. In these cytochrome P-450-dependent lipid peroxidation systems, pretreatment of microsome with trisulfide derivatives (cystine trisulfide and thiocyclam) significantly inhibited TBA-RS formation and oxygen consumption compared with disulfide or thiol analogs (cystine, nereistoxin, or cysteine). The labile sulfur contained in trisulfide disappeared during incubation with liver microsomes. In the CCl4-induced lipid peroxidation system, the cytochrome P-450 level and NAD(P)H-cytochrome P-450 reductase activity were significantly decreased by the addition of trisulfide derivatives. Therefore, in cytochrome P-450-dependent lipid peroxidation system, the potential effects of trisulfide appear to be mediated via enzyme inhibition. These results suggest that pretreatment of the trisulfide derivatives may affect the toxic function of exogenous xenobiotics or drugs, which are reduced by the liver enzyme cytochrome P-450 to radical species.

Animals↗
PubMed1998

The GroEL-like protein from Campylobacter rectus: immunological characterization and interleukin-6 and -8 induction in human gingival fibroblast.

The native GroEL-like protein was purified from Campylobacter rectus, a putative periodontal pathogen, by affinity chromatography on ATP-agarose followed by high performance liquid chromatography on Superose 6. The purified 64-kDa protein (denatured form of GroEL-like protein) was immunoreactive by SDS-PAGE and Western immunoblotting with the monoclonal antibody directed against heat shock protein 60 of human origin. The native GroEL-like protein stimulated both interleukin-6 (IL-6) and IL-8 secretion by a confluent monolayer of human gingival fibroblast in their culture supernatant. During the 22-h incubation, the amounts of IL-6 and IL-8 were increased by 5.4- and 3.5-fold, respectively. These data suggested that the GroEL-like protein might be considered to be a virulence factor of C. rectus in periodontal disease.

Amino Acid Sequence↗
PubMed1998

Intramolecular cross-linking of the extrinsic 33-kDa protein leads to loss of oxygen evolution but not its ability of binding to photosystem II and stabilization of the manganese cluster.

The extrinsic 33-kDa protein of photosystem II (PSII) was intramolecularly cross-linked by a zero-length cross-linker, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The resulting cross-linked 33-kDa protein rebound to urea/NaCl-washed PSII membranes, which stabilized the binding of manganese as effectively as the untreated 33-kDa protein. In contrast, the oxygen evolution was not restored by binding of the cross-linked protein, indicating that the binding and manganese-stabilizing capabilities of the 33-kDa protein are retained but its reactivating ability is lost by intramolecular cross-linking of the protein. From measurements of CD spectra at high temperatures, the secondary structure of the intramolecularly cross-linked 33-kDa protein was found to be stabilized against heat treatment at temperatures 20 degrees C higher than that of the untreated 33-kDa protein, suggesting that structural flexibility of the 33-kDa protein was much decreased by the intramolecular cross-linking. The rigid structure is possibly responsible for the loss of the reactivating ability of the 33-kDa protein, which implies that binding of the 33-kDa protein to PSII is accompanied by a conformational change essential for the reactivation of oxygen evolution. Peptide mapping, N-terminal sequencing, and mass spectroscopic analysis of protease-digested products of the intramolecularly cross-linked 33-kDa protein revealed that cross-linkings occurred between the amino group of Lys48 and the carboxyl group of Glu246, and between the carboxyl group of Glu10 and the amino group of Lys14. These cross-linked amino acid residues are thus closely associated with each other through electrostatic interactions.

Amino Acid Sequence↗
PubMed1998

The Two Nuclei in the Dikaryon of the Homobasidiomycete Coprinus cinereus Change Position after Each Conjugate Division

We constructed a common-AB diploid strain of Coprinus cinereus and mated this to a compatible haploid strain to construct a diploid-haploid dikaryon. We examined the positions of the diploid and haploid nuclei in the apical and subapical cells of the dikaryon by fluorescence microscopy and microfluorometry. In 60% of apical cells the leading nucleus (the nucleus proximal to the hyphal apex) was diploid and the second nucleus (the nucleus distal to the apex) was haploid, whereas in the remaining 40% of apical cells the order of the two nuclei was reversed. It was also observed that in 97% of hyphae examined the order of the diploid and haploid nuclei was reversed between the apical cell and the subapical cell. Based on these observations, we conclude that the two nuclei alternate in taking the leading and second positions in the apical cell at almost every conjugate division in the dikaryon. Copyright 1998 Academic Press.

Journal Article↗
PubMed1998

Accumulation Features of Polychlorinated Biphenyls and Organochlorine Pesticides in Resident and Migratory Birds from South India

Persistent organochlorines such as DDT and its metabolites (DDTs), hexachlorocyclohexane isomers (HCHs), chlordane compounds (CHLs), hexachlorobenzene (HCB), and polychlorinated biphenyls (PCBs) were determined in whole-body homogenates of resident and migratory birds collected from South India. Organochlorine contamination pattern in birds varied depending on their migratory behaviour. Resident birds contained relatively greater concentrations of HCHs (14-8,800 ng/g wet wt) than DDTs and PCBs concentrations. In contrast, migrants exhibited elevated concentrations of PCBs (20-4,400 ng/g wet wt). The sex differences in concentrations and burdens of organochlorines in birds were pronounced, with females containing lower levels than males. Inland piscivores and scavengers accumulated greater concentrations of HCHs and DDTs while coastal piscivores contained comparable or greater amounts of PCBs. Global comparison of organochlorine concentrations indicated that resident birds in India had the highest residues of HCHs and moderate to high residues of DDTs. It is, therefore, proposed that migratory birds wintering in India acquire considerable amounts of HCHs and DDTs. Estimates of hazards associated with organochlorine levels in resident and migratory birds in India suggested that Pond Heron, Little Ringed Plover, and Terek Sandpiper may be at risk from exposure to DDTs.

Journal Article↗
PubMed1998

Age-dependent accumulation of heavy metals in baikal seal (Phoca sibirica) from the Lake Baikal.

Concentrations of Fe, Mn, Zn, Cu, Cd, and Hg were determined in the liver, kidney, and muscle of 60 Baikal seals collected from Lake Baikal in 1992 to investigate age-dependent accumulation. Among essential elements, Fe concentrations in the muscle, liver, and kidney increased with age, suggesting development of diving ability. The concentrations of Mn, Zn, and Cu decreased with age, especially at immature stages. Toxic elements such as Hg and Cd decreased in adult males and thus the male-female difference was clearly observed in their concentrations, which differed from patterns usually found in marine mammals. Such accumulation patterns were due to difference in the feeding rates between males and females under low exposure to Hg and Cd. In addition, a greater excretion of Hg than that of Cd through molting and parturition was estimated.

Aging↗
PubMed1998

Distribution of 14 elements in tissues and organs of oceanic seabirds.

The concentrations of 14 trace elements (Li, V, Mn, Co, Cu, Zn, Se, Rb, Sr, Ag, Cd, Cs, Pb, and Hg) were determined in tissues and organs of three species and in the liver of 11 species of seabirds. Comparatively high concentrations of Li, Co, Sr, and V were found in the femur. Cd, Se, Cu, and Mn concentrations were relatively higher in the kidney than in other tissues and organs. Rb, Cs, and Pb concentrations were rather uniform among tissues. Concentrations of essential elements such as Mn, Cu, and Co were comparable among seabird species, except high Cu concentrations in northern giant petrel. Among nonessential elements, concentrations of Cd and Hg were variable according to seabird species. Pb levels were low in all the species. High Se levels (100 microg/g dry weight) were found in the liver of black-footed albatross and grey petrel. There were significant positive correlations between Se and Cd concentrations in three species and between Se and Hg in black-footed albatross, suggesting that Se has an antagonistic action on the toxic effects of Cd and Hg. Concentrations of Li, V, Ag, and Cs were usually low (less than 1 microg/g dry weight).

Animals↗
PubMed1998

Intellectual functions and regional cerebral haemodynamics after extensive omental transplantation spread over both frontal lobes in childhood moyamoya disease.

Most accepted operations for childhood moyamoya disease have attempted to increase cerebral blood flow (CBF) in the ischaemic cortical areas around the central fissure. Developed ischaemic brain damage in the prefrontal area may lead to poor intellectual outcome and restrict patients' daily lives. Thus, extensive cerebral revascularization in both the ischaemic anterior and middle cerebral artery territories is mandatory. We describe the long-term follow-up results for intellectual outcome and performance status and make an evaluation of regional cerebral haemodynamics after extensive omental transplantation spread over both frontal lobes performed as the initial management. In the past 10 years, 10 moyamoya patients less than 12 years of age consecutively underwent omental transplantation. The omental flap was spread over not only the symptomatic hemisphere but also the contralateral frontal lobe after a large craniotomy. Superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis was accomplished simultaneously. On the contralateral hemisphere, STA-MCA anastomosis combined with encephalomyosynangiosis was subsequently performed. The clinical observation period averaged 6.7 years (ranged 1.9 to 9.2 years). Apart from 2 patients in whom severe mental retardation had been disclosed pre-operatively, full-scale intelligence quotient scores have been maintained at over 90, that is, within the normal intellectual range. With respect to quality of life (QOL), these 8 patients have been leading normal daily lives since the operation. The focal decrease in CBF observed in the frontal lobe pre-operatively in 7 cases had disappeared after surgical treatment. In these patients, serial post-operative MR angiography revealed developed omental vessels and STAs. Deterioration of intellectual functions and QOL as well as cerebral ischaemic events in paediatric moyamoya patients can be prevented by extensive omental transplantation spread over both frontal lobes combined with STA-MCA anastomosis.

Cerebral Revascularization↗
PubMed1998

Organochlorine pesticides and polychlorinated biphenyl congeners in wild terrestrial mammals and birds from Chubu region, Japan: interspecies comparison of the residue levels and compositions.

In order to understand the residue levels of organochlorine compounds (OCs) and their accumulation patterns in wildlife inhabiting Chubu region, Japan, the concentrations of polychlorinated biphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), DDT compounds (DDTs) and hexachlorobenzene (HCB) were measured in 8 species of terrestrial mammals and 10 species of birds. In view of feeding habits, the contamination levels of OCs were found to be higher in omnivorous mammals than in herbivorous ones, and in fish-eating ones and raptores than in omnivorous birds. In fox and dog, PCB-180 (2, 2', 3, 4, 4', 5, 5'-heptachlorobiphenyl) was the most dominant PCB congener, while in the other species PCB-153 (2, 2', 4, 4', 5, 5'-hexachlorobiphenyl) was the most persistent. The ratios of lower chlorinated PCB congeners (tri- to tetra-) to total PCBs were larger in fish-eating birds than in the other birds. The results indicate that the compositions of PCB congeners would reflect the differences of feeding habits and xenobiotic metabolizing systems among each species.

Animals↗
PubMed1998

Intracranial facial nerve neurinoma: surgical strategy of tumor removal and functional reconstruction.

BACKGROUND: Three cases with intracranial facial neurinoma underwent tumor removal and facial nerve reconstruction with or without tympanoplasty. Surgical strategy for each case was tailored to: (1) the site of main tumor mass, (2) its extension along the facial nerve, and (3) involvement of the auditory organs. METHODS: Surgeries adopted in the three cases were: transpetrosal approach with intracranial-intratemporal facial nerve anastomosis, middle fossa and transmastoid approach with intratemporal facial nerve anstomosis and tympanoplasty, and middle fossa and transmastoid approach with intracranial-intratemporal facial nerve anastomosis and tympanoplasty. The greater auricular nerve was used as the nerve graft for all three cases. RESULTS: In the follow-up period of 8-13 months there was no tumor recurrence; facial function was scored 20/90 in modified May's scoring system in each case, but two are still in the process of functional recovery. One of the two cases who underwent tympanoplasty showed complete recovery of hearing within 1 month, and the other showed worsened hearing, which was not serviceable at 3 months postoperatively. CONCLUSION: Systematic surgical approach for tumor removal, facial nerve reconstruction, and auditory reconstruction should be considered in cases with intracranial facial neurinoma due to its varied clinical features.

Aged↗
PubMed1998

In vitro inhibition of hepatic cytochrome P450 and enzyme activity by butyltin compounds in marine mammals.

The present study attempted to examine the in-vitro inhibition of hepatic microsomal P450 content and activity by butyltins in marine mammals and discussed on their possible effects in animals in the wild. Decreases in P450 content and the activities of ethoxyresorufin O-deethylase (EROD, catalyzed by CYPIA subfamily) and penthoxyresorufin O-depentylase (PROD, catalyzed by CYP2B subfamily) by tributyltin (TBT) were observed in in-vitro experiments using hepatic microsomes of a pinniped and a cetacean. Among P450 family, EROD activity is more sensitive to TBT than P450 content and PROD activity, indicating a specific mode of action of TBT on different P450 forms. On the other hand, dibutyltin and monobutyltin have no inhibitory effect on EROD activity at concentrations less than 0.5 mM, indicating that the inhibition of enzyme activity in hepatic microsome of marine mammal is mainly by TBT. TBT concentrations that affect P450 contents and activities are above 10 times higher than the values found in the liver of various marine mammals.

Journal Article↗