Biomedical subjects

K Urano

Publications and source records attributed to K Urano.

At least 37 records · Page 2Linked to original sources

PubMed1996

A new approach to analysis of human sweating.

In human skin transplanted to the back of 3 strains of immuno-deficient mice the function of the eccrine sweat glands of the human transplant was tested by topical intradermal application of pilocarpine, adrenaline and atropine + pilocarpine. Sweat responses were observed in pre-selected fields of observation by means of video macroscope. The iodine starch reaction served as an indicator for the appearance of sweat sport and permitted the evaluation of areas wetted by sweat in the field of observation. Among 9 animals tested, the hybrids between the CB-17-scid mouse and the BALB/cA-nu mouse (BALB/cA-nu,scid) seemed to exhibit the most consistent sweating response to local pharmacological stimulation. According to histological examination, eccrine sweat glands were preserved in human skin transplanted into the back skin of the BALB/cA-nu,scid mouse strain. The heterologous, human skin graft provides a novel model permitting, independent of the normal sweat gland innervation, the analysis of molecular receptors of sweat gland cells by which the actions of natural transmitters and pharmacological agents are transduced.

Animals↗

PubMed1996

Macromolecule-macromolecule interaction in drug distribution. IV. Molecular weight dependency in the interaction of fractionated [3H]heparin with plasma proteins.

Molecular weight dependency in the interaction of fractionated [3H]heparin (FH) with plasma proteins was evaluated by determining the protein binding of low molecular weight fractionated [3H]heparin (LMWFH: 7000 Da) and high molecular weight fractionated [3H]heparin (HMWFH: 16000 Da) by ultrafiltration and the effects of plasma proteins on the uptake in rat hepatocytes in primary culture. The unbound fractions of LMWFH were 0.5 and 0.8 in the presence of alpha-globulin and albumin, respectively, and were about 10 times larger than those of HMWFH, 0.04 and 0.1, suggesting a reduction in binding with a decrease in molecular weight. However, while the uptake of LMWFH was reduced by these proteins by the extents similar to bound fractions of LMWFH, the uptake of HMWFH was reduced by extents far smaller than bound fractions and comparable with those for LMWFH. Thus, it seemed that, while only unbound LMWFH is available for uptake, HMWFH bound to proteins is to some extent available for uptake (protein-mediated transport). The protein-mediated transport of heparin seemed to reduce with a decrease in molecular weight. It was also shown that the extended uptake of LMWFH was smaller than that of HMWFH not only in the absence of proteins but also in the presence of alpha-globulin, the major binding protein. The lower uptake of LMWFH is consistent with in vivo suggestion of lower hepatic accumulation.

Animals↗

PubMed1996

Uptake mechanism of fractioned [(3)H]heparin in isolated rat kupffer cells: involvement of scavenger receptors.

The uptake of fractionated [(3)H]heparin was examined to elucidate the uptake mechanism in isolated rat Kupffer cells. The equilibrium binding of fractionated [(3)H]heparin to Kupffer cells was concentration-dependent with the dissociation constant of 5.7 nM and the maximum binding capacity of 1.5 pmol/10(6) cells. Several ligands of scavenger receptors inhibited the binding of fractionated [(3)H]heparin to Kupffer cells competitively and also the internalization of heparin, suggesting the involvement of scavenger receptors in the uptake of fractionated [(3)H]heparin. Fractionated [(3)H]heparin was also suggested to be internalized according to first order kinetics with the apparent internalization rate constant of 0.010 min (-1). Lowering temperature from 37 to 4 degrees C reduced the fraction internalized from 33% to 6% without affecting the total association, while the fraction internalized at 25 degrees C was comparable with that at 37 degrees C. Metabolic inhibitors (2,4-dinitrophenol and rotenone), an inhibitor of receptor-mediated and adsorptive endocytosis of polypeptides (phenylarsine oxide) and phagocytosis inhibitors (cytochalasine B and colchicine) did not inhibit the internalization of fractionated [3(H)]heparin. As known inhibitors of receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis did not affect the uptake of fractionated heparin, the scavenger receptor-mediated uptake is suggested to be ATP-independent and different from receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis, although for temperature dependency it showed the typical characteristics of receptor-mediated endocytosis.

2,4-Dinitrophenol↗

PubMed1996

Molecular weight dependency in the uptake of fractionated [3H]heparin in isolated rat Kupffer cells.

The uptake of low molecular weight fractionated [3H]heparin (LMWFH, 10000 Da) was compared with that of high molecular weight fractionated [3H]heparin (HMWFH, 23000 Da) in isolated rat Kupffer cells. Several heparin analogs, including HMWFH and ligands of scavenger receptors, inhibited both the surface binding and internalization of LMWFH, suggesting the involvement of scavenger receptors in the uptake of LMWFH in isolated rat Kupffer cells as well as HMWFH, in spite of a large difference in molecular weight. Metabolic inhibitors (2,4-dinitrophenol and rotenone), receptor-mediated and adsorptive endocytosis of polypeptides (phenylarsine oxide) and phagocytosis inhibitors (cytochalasine B and colchicine) did not inhibit the internalization of LMWFH. These results suggest that the scavenger receptor-mediated uptake of LMWFH is ATP-independent and different from receptor-mediated and adsorptive endocytosis of polypeptides and phagocytosis, in agreement with our previous results for HMWFH. The equilibrium binding of LMWFH to Kupffer cells was concentration-dependent with the dissociation constant (Kd) of 50 nM and maximum binding capacity (Bmax) of 2.3 pmol/10(6) cells. The dissociation constant of LMWFH was an order of magnitude larger than that of HMWFH (5.7 nM), suggesting a decrease in binding affinity to scavenger receptors with a decrease in the molecular weight of fractionated heparin. It was also shown that LMWFH is internalized by scavenger receptors according to first-order kinetics with an apparent internalization rate constant (Kint,app) of 0.0053 min-1, which is about half that for HMWFH (0.0118 min-1). Molecular weight thus appears to be one of dominant factors determining the uptake of fractionated heparin by scavenger receptors in Kupffer cells, and may partly explain the reported lower hepatic uptake of low molecular weight heparin than that of unfractionated heparin.

2,4-Dinitrophenol↗

PubMed1995

Biodegradation ranks of priority organic compounds under anaerobic conditions.

The biodegradations of 52 priority organic compounds were evaluated under anaerobic conditions by two tests developed in a preceding paper (Urano et al., 1995). Namely, the biodegradabilities of the compounds were classified into 13 ranks by the method proposed by Urano et al. (1995). Most of the aliphatic alcohols and carboxylic acids were not inhibitory and were biodegraded, but the compounds having ether bonds or branched hydrocarbon groups were biodegraded slowly. Aliphatic aldehyde and amines were not so much inhibitory but were hardly biodegraded. The benzene substitutes having groups of -CH2OH, -CHO, -CH2CH(NH2)COOH, -COOH and -OH were easily biodegraded, but the compounds having groups of -NO2, -NH2 and -SO3H were hardly biodegraded. Most of the nitro compounds were inhibitory in the higher concentration test though they were reduced into amino compounds. Since the biodegradation characteristics of many organic compounds could be classified and discussed appropriately, the suitability of the proposed method is substantiated.

Anaerobiosis↗

PubMed1995

Testing and classification methods for the biodegradabilities of organic compounds under anaerobic conditions.

Biodegradability is one of the most important characteristics of an organic compound for predicting its fate and life in the environment and its application in biological wastewater treatment. But there is no general testing method for biodegradability under anaerobic conditions. The biodegradabilities of thirteen principal organic compounds was investigated in a batch test using vials under various conditions, such as the concentration of an organic compound, the cultivation method and the concentration of anaerobic bacteria for seeding. Two test methods in the standard concentration and the low concentration were developed. A new method to classify the biodegradabilities of organic compounds into thirteen ranks was proposed by considering inhibition, complete biodegradation and first step biodegradation.

Bacteria, Anaerobic↗

PubMed1995

Failure of genotoxic carcinogens to produce tumors in human skin xenografts transplanted to SCID mice.

Chemical carcinogenesis of human skin was investigated using human skin xenografts (16 full thickness and 48 split thickness skin grafts) transplanted to CB-17-scid (SCID) mice. Topical application of a carcinogen, i.e. 7,12-dimethylbenz[a]anthracene (DMBA), benzo[a]pyrene, methylcholanthrene or N-methyl-N'-nitro-N-nitrosoguanidine, to the human skin xenografts once a week for 25-30 weeks failed to produce skin tumors. Both DMBA application plus UV-B irradiation and alternate applications of the above four carcinogens in combination with UV-B irradiation also failed to produce tumors. All of these treatments induced skin papillomas in skins of host SCID mice. DMBA induced skin papillomas in allogenic CD-1 mouse skin grafts transplanted to SCID mice. These results indicate that susceptibility of human skin to these carcinogenic stimuli is much lower than that of mouse skin.

Animals↗

PubMed1995

PUVA suppresses the expression of cell adhesion molecules of lymphocytes.

To determine the therapeutic mechanism of PUVA in psoriasis vulgaris, the effects of PUVA on activated T lymphocytes were investigated in vitro. Peripheral blood mononuclear cells (PBMC) obtained from healthy volunteers were activated with Con A stimulation (Con A blasts). Both untreated PBMC and Con A blasts were irradiated with UVA light in the presence of 8-methoxypsoralen (8-MOP). The expressions of CD4, CD8, VLA-4 and LFA-1 of PBMC and Con A blasts were stained with each monoclonal antibody and the intensity of fluorescence was analyzed by FACScan. PUVA-treated PBMC showed decreased response to both Con A and PHA stimulation. PUVA treatment also suppressed the IL-2 production of Con A blasts and IL-2 response of PBMC with increasing UVA fluence. The expressions of LFA-1, VLA-4, CD4, CD8 and CD25 (IL-2R) molecules were decreased in PUVA-treated Con A blasts. Con A blasts were more sensitive than untreated PBMC to PUVA treatment. These results suggest that the therapeutic effects of PUVA on psoriasis vulgaris can be induced by suppression of the expression of cell surface molecules of activated T lymphocytes.

Cell Adhesion Molecules↗

PubMed1995

Uptake of low molecular weight fractionated [3H]heparin by rat hepatocytes in the primary culture.

The uptake of low molecular weight fractionated [3H]heparin (LMWFH: 7000 Da) was examined, for comparison with that of high molecular weight fractionated [3H]heparin (HMWFH:20000 Da), in a primary culture of rat hepatocytes. The uptake of LMWFH increased almost linearly with time up to 60 min (extended uptake), although a faster uptake was observed in the initial 2 min (initial uptake). Both the initial and extended uptake were saturable, and the maximum uptake velocity (Vmax) and the Michaelis constant (Km) were estimated to be 10.7 pmol/min/mg protein and 398 nM, respectively, for the initial uptake and 0.34 pmol/min/mg protein and 116 nM, respectively, for the extended uptake. The Km for the extended uptake was 5 times larger than that of 21 nM for HMWFH, but the other parameters were comparable with those for HMWFH. Thus, an increase in Km, or a decrease in the apparent affinity, with a decrease in molecular weight in the extended uptake may be responsible for the reported lower hepatic uptake of low molecular weight heparin, compared with unfractionated heparin. It was also shown that both the initial and the extended uptake of LMWFH were inhibited by several analogs of heparin, including HMWFH, and anionic compounds such as 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), suggesting that LMWFH and HMWFH, in spite of a large difference in the molecular weight, share the same specialized uptake mechanism, in which an anionic moiety and/or heparin-like structure plays an important role.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed1994

Influence of chemicals commonly found in a water environment on the Salmonella mutagenicity test.

The influence of 16 organic chemicals commonly found in a water environment--such as phenols, phthalic esters and phosphoric esters--on the Salmonella mutagenicity test was investigated. The test chemicals were subjected to the mutagenicity test using a fixed dose of various positive standard mutagens such as 2-nitrofluorene, Trp-P-1, Trp-P-2, 2-aminofluorene and benzo[a]pyrene, thus testing them for their influence on the mutagenic activities. The influence of each chemical was classified into one of five groups as follows: (1) toxic and inhibitory to mutagenicity; (2) toxic and promotive to mutagenicity; (3) non-toxic and inhibitory to mutagenicity; (4) non-toxic and promotive to mutagenicity; and (5) non-toxic and having no effect on mutagenicity. It is concluded that chemicals in the water environment may influence the results of a mutagenicity test on environmental samples. In particular, an effect may be noted with regard to wastewater and sediments which contain these chemicals in higher concentrations eventhough they themselves are not mutagenic.

Hydrocarbons↗

PubMed1993

Potentiation of therapeutic effect of recombinant tumor necrosis factor against B16 mouse melanoma by combination with recombinant interleukin 2.

Treatment of B16 melanoma-bearing mice with recombinant tumour necrosis factor (rTNF) caused a marked inhibition of tumour growth but did not result in the complete cure of the tumour-bearing mice. In contrast, combination therapy of B16-bearing mice with r-TNF and recombinant interleukin 2 (rIL-2) potentiated the therapeutic effect of rTNF and 30% of the mice were totally cured from tumour. Spleen cells obtained from B16-bearing mice showed markedly decreased immune responses including IL-2 production, IL-2 responsiveness and mixed lymphocyte reaction owing to the existence of suppressor macrophages. However, spleen cells obtained from mice cured with rTNF plus rIL-2 showed the same level of T cell responsiveness as that from normal mice. The decreased induction of alloantigen-specific cytotoxic T lymphocytes (CTL) in B16-bearing mice was also recovered after treatment with rTNF plus rIL-2. Moreover, B16-specific CTL, which could not be induced in normal or B16-bearing mice, was effectively induced from the spleen cells of B16-cured mice by rTNF and rIL-2. These results demonstrated that local therapy of melanoma with rTNF and rIL-2 was effective and induced systemic antitumour immunity in vivo.

Animals↗

PubMed1993

Macromolecule-macromolecule interaction in drug distribution. III. Kinetic characterization of the uptake of fractionated [3H]heparin and the effect of plasma proteins in the perfused rat liver.

The concentration-dependent hepatic uptake of fractionated [3H]heparin, a macromolecular model drug, was kinetically characterized and the effect of plasma proteins, albumin and alpha-globulin, was evaluated in the perfused rat liver as part of an ongoing effort to elucidate the mechanism of interaction of macromolecular drugs with biological macromolecules and the role of this interaction in the drugs' distribution. In the absence of proteins, the uptake of fractionated [3H]heparin was saturable with the maximum uptake velocity (Vmax) of 7.6 pmol/min/g liver and the Michaelis constant (Km) of 32.2 nM, suggesting the involvement of a specialized transport. alpha-Globulin (8.0 mg/ml) reduced the uptake of fractionated [3H]heparin at lower heparin at lower heparin concentrations. However, albumin (40 mg/ml) did not affect the uptake of fractionated [3H]heparin, suggesting an insignificant interaction. Assuming that fractionated [3H]heparin bound to alpha-globulin cannot be uptaken and that the reduction in uptake was solely attributable to the saturable Scatchard-type binding of fractionated [3H]heparin to alpha-globulin, the dissociation constant (Kd) and the binding capacity (n) were estimated to be 2.1 nM and 0.002, respectively. In in vitro binding experiments by ultrafiltration, Kd and n were estimated as 168 nM and 0.5, respectively, for alpha-globulin and 1021 nM and 0.02, respectively, for albumin, suggesting lower affinity and higher capacity in vitro for each protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Monoclonal antibody against actin cross-reacts with the Thy-1 molecule and inhibits lymphocyte function-associated antigen-1 dependent cell-cell interaction of T cells.

To assess the molecular mechanisms involved in cell-cell interactions of T cells, we produced a mAb that could block PMA-induced homotypic T cell aggregation. The established mAb (TN14 mAb) showed an inhibitory effect on T cell aggregation as large as that of mAb against lymphocyte function-associated Ag-1. TN14 mAb showed a strong reactivity with cell surface molecules on T cells, whereas it did not react with any cell surface Ag on macrophages, B cells, bone marrow cells, or WEHI 164 cells, which were used for immunization. However, all cell lysates could react with TN14 mAb in Western blotting analysis, indicating that TN14 mAb recognized some cytoplasmic protein. From biochemical analysis, TN14 mAb was demonstrated to react with the 43-kDa cytoskeletal protein actin. Moreover, from an immunoprecipitation study, TN14 mAb was demonstrated to cross-react with the Thy-1 molecule on T cells. The binding activity of TN14 mAb with the Thy-1 molecule on T cells was strongly blocked by the addition of purified actin, indicating that TN14 mAb recognized an actin-related epitope of the Thy-1 molecule. TN14 mAb blocked not only T cell aggregation but also cell-mediated cytotoxicity by CTL. These results strongly support the hypothesis that the Thy-1 molecule, a member of the Ig superfamily, may play an important role in cell-cell interactions of T cells.

Actins↗

PubMed1991

[Detection of point mutation of Kirsten ras oncogene in pancreatic carcinoma by polymerase chain reaction].

Regarding to the pancreatic cancer, outcomes of the patients surgically treated have been poor. By using polymerase chain reaction (PCR), paraffin-embedded specimens of the pancreatic carcinoma were confined point mutation in Kirsten (K)-ras codon 12. Then, incidence and type of point mutation of this oncogene and correlative studies with stage, T or N factor of pancreatic cancer were analysed. Extremely high incidence of K-ras gene mutation was shown in present report. The highest mode of point mutation of K-ras oncogene was GGT to GAT coded aspartic acid. Cases without point mutation in K-ras codon 12 were significantly frequent in papillary adenocarcinoma than in tubular type. There were not correlative result among mutation types, stage and T factor of pancreatic cancer. Most patients with pancreatic cancer who survived more than 2 years have not shown mutation to aspartic acid. Four cases including two cases of mucin producing pancreatic cancer did not have point mutation in K-ras codon 12. Pathogenesis of mucin producing cancer can be distinguished from typical pancreatic cancer by detection of point mutation in K-ras codon 12 using PCR.

Codon↗

PubMed1990

Pollution by the fungicide pentachloronitrobenzene in an intensive farming area in Japan.

Environmental pollution by pentachloronitrobenzene (PCNB) was investigated at Tsumagoi, an intensive farming area, where a great amount of PCNB has been applied. High concentrations of PCNB were detected in river water near an area of cabbage cultivation. Further, pentachloroaniline (PCA) and pentachlorothioanisole (PCTA), which are the principal biodegradation products of PCNB, were also detected, and their ratios to PCNB were higher in autumn than in summer. PCNB concentrations in soil were similar to those of river sediment, in which PCNB was concentrated 5000-10,000 times over levels in river water. The biodegradation rate of PCNB in river water was higher than in river sediment and soil. The formation rates of PCA from PCNB were higher in river sediment and soil than in river water. It is considered that PCA remains for a long time in the environment and accumulates in river sediment and soil.

Agriculture↗

PubMed1988

Chlorinated organic compounds in urban air in Japan.

Air pollution by the principal chlorinated organic compounds chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene and tetrachloroethylene was investigated over a period of approximately 1 year at 15 sites in an urban area. Each compound was detected in the range from approximately 0.1 to several ppb; the concentrations of these compounds, with the exception of carbon tetrachloride, were higher than their global pollution levels. The concentrations of 1,1,1-trichloroethane and trichloroethylene especially were very high in the industrial regions, and the concentration of tetrachloroethylene was very high in the industrial and commercial regions. Concentrations were low in spring and summer and high in fall, winter and the rainy season. The correlation between the reciprocal of wind speed and concentrations was found to be subject to seasonal variations. Intake of chlorinated organic compounds by man from the air was estimated from the data to be larger than the allowable intakes determined by WHO and EPA for drinking water.

Air Pollutants↗

PubMed1988

Method for evaluating mutagenicity of water. I. A new method of preparing samples for mutagenicity test.

A sample preparation method for a convenient and quantitative mutagenicity test of water was developed using two new superior resinous adsorbents. One, CSP800, is a small particle size and highly porous polystyrene resin, and the other, CHPA25, is a small particle size and highly porous anion-exchange resin. CSP800 adsorbed more nonionic compounds from water than conventional resins, and CHPA25 adsorbed anionic compounds not adsorbed by conventional resins. Sample water (10 l) at pH 5 was fed at 550 ml h-1 into two columns in series, one containing 5 ml of CSP800 and the other 2 ml of CHPA25. The adsorbed substances were subsequently desorbed by DMSO from CSP800 and by 4 N NaNO3 from CHPA25, at 10 ml h-1. Various organic substances, which were measured by different indices such as total trihalomethanes (THM), total organic halogen (TOX) and the absorbence at 260 nm, could be recovered by this method much more efficiently and conveniently than by conventional methods.

Chromatography, Ion Exchange↗

PubMed1988

Method for evaluating mutagenicity of water. II. Conditions for applying new sample preparation method to the Ames test.

Conditions for the application of a new sample preparation method developed in a previous study using the small particle size and highly porous polystyrene and anion-exchange resins CSP800 and CHPA25 were investigated. The desorbing solvents DMSO and 4 N NaNO3 (0.5 ml), corresponding to 11 of water sample, could be dosed on a plate for the mutagenicity test, the Ames test. It was confirmed that trace impurities from the resins were not mutagenic. The mutagenicity of several drinking water samples was determined by this new method and evaluated quantitatively by converting to the concentrations of the standard mutagens, 4-nitroquinoline-1-oxide and 2-aminoanthracene, without S9 and with S9 respectively. Furthermore, the mutagenicity of the nonionic pollutants adsorbed on CSP800 and that of the anionic pollutants adsorbed on CHPA25 could be evaluated separately.

Dose-Response Relationship, Drug↗