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Biomedical subjects

M Kimoto

Publications and source records attributed to M Kimoto.

At least 163 records · Page 9Linked to original sources
PubMed1988

B lymphocyte lineage-restricted expression of mb-1, a gene with CD3-like structural properties.

A gene, called m-mb-1, was isolated from a murine pre-B-minus T lymphocyte subtracted library. It was found expressed as mRNA at low to medium abundance in early progenitors of the B lineage, in pre-B and mature B lineage cell lines, in normal resting B lymphocytes and in polyclonally activated B cell blasts. The gene was not expressed in plasmacytomas, in cell lines of the monocyte/macrophage, the T lymphocyte or the fibroblast lineages, nor in thymus, liver, heart, kidney, lung or brain. The nucleotide sequence of the m-mb-1 gene encodes a putative membrane glycoprotein with 220 amino acids, which includes a leader sequence, a putative extracellular domain with two potential N-glycosylation sites, a transmembrane portion and a putative intracellular domain. The partial sequence of a human homologue, h-mb-1, shows nearly 90% homology in nucleotide as well as amino acid sequences to the murine form of a stretch of the putative intracytoplasmic domain. Antibodies raised against a fusion protein of m-mb-1 with protein A, affinity purified for their m-mb-1 specificity, stained pre-B and mature B cell lines on their surface, but did not stain T cell lines and fibroblasts. Antibodies raised against a stretch of 20 amino acids of the putative intracellular domain with 90% homology between the mouse and human protein did not stain the surface of any cell lines tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1988

The hypocholesterolemic action of the undigested fraction of soybean protein in rats.

Soybean protein was exhaustively digested with endo- and exo-type microbial proteases and the effect of the digestible low molecular fraction (LMF) and the undigested high molecular fraction (HMF) on the serum cholesterol level was compared to that of the intact protein in rats given a cholesterol-enriched diet. The HMF, peptides relatively abundant in hydrophobic amino acids, was found to be substantially hypocholesterolemic when fed at the nitrogen level equivalent to that of the 20% soybean protein diet, and not only serum but also liver cholesterol levels were similar to those usually encountered in rats given diets free of cholesterol. There was a dose-dependent reduction of serum and liver cholesterol when casein was replaced stepwise with HMF. The cholesterol-lowering action could be attributable to an increased fecal steroid excretion.

Animals↗
PubMed1988

Effects of perfusion pressure during flushing on the viability of the procured liver using noninvasive fluorometry.

The influence of perfusion pressure and flow rate on hepatic cellular viability was investigated in the procured liver using noninvasive pyridine nucleotide fluorometry, in relation to other metabolic indices such as nicotinamide adenine dinucleotide (NAD) concentration, adenine nucleotides, tissue ketone bodies, and mitochondrial phosphorylative activity. Rat liver was perfused at a controlled flow rate through the portal vein with a nonrecirculating open-end-design perfusion system driven by a roller pump using cooled oxygenized Euro-Collins' solution. The maximum pressures (mean pressure in parentheses) of experimental groups were 8 (5) mmHg, 15 (9) mmHg, 40 (25) mmHg, 80 (50) mmHg, 120 (73) mmHg, 240 (152) mmHg. The amplitude between oxidation and reduction levels (RxA) in the fluorometric trace, and the gradient or velocity of the trace curve from oxidation to reduction (RxV) were determined by the measurement of fluorescence from NAD phosphate, reduced form (NADPH) using a new fluorometric device. Other metabolic indices were measured after attainment of a fully oxygenated state. RxA decreased in accordance with the increase of pressure. Similar results were obtained in the changes of NAD concentration, total adenine nucleotides, and total tissue ketone bodies, possibly due to the wash-out of these metabolites. RxV decreased in inverse proportion to the increase of pressure. There were close positive correlations between RxV and tissue ketone body ratio (acetoacetate/3-hydroxybutyrate) (r = 0.793, less than 0.01), RxV and respiratory control ratio in isolated mitochondria (r = 0.617, P less than 0.05), RxV and state 3 respiration (r = 0.792, P less than 0.01), and RxV and phosphorylation rate (r = 0.833, P less than 0.01). These results suggest that perfusion pressure and flow rate can easily deteriorate the energy metabolism of the procured liver, and that the gravity-induced hydrostatic pressure presently used in procurement perfusion should be reevaluated on the basis of energy metabolism.

Animals↗
PubMed1988

Effect of helper and/or cytotoxic T-lymphocyte depletion on low-dose streptozocin-induced diabetes in C57BL/6J mice.

The low-dose streptozocin (STZ) model of diabetes has been reported to involve direct STZ beta-cytotoxicity and/or immunologically mediated beta-cell destruction. Because the T-lymphocyte dependency of such a model is controversial, we further assessed the role of T-lymphocytes by determining the occurrence and magnitude of hyperglycemia as well as the pancreatic insulin contents in both STZ-injected nude C57BL/6J male mice and STZ-injected euthymic C57BL/6J male mice selectively depleted in helper and/or cytotoxic T-lymphocytes with monoclonal antibodies (MoAbs). The effectiveness of MoAb treatment was assessed in lymph node cells by flow-microfluorometry analysis and in spleen cells by concanavalin A stimulation, allospecific cytotoxic T-lymphocyte activity, and T-lymphocyte lymphokine production. Sixteen days after the first STZ injection, hyperglycemia (plasma glucose greater than 200 mg/dl) occurred in significantly fewer helper T-lymphocyte-depleted mice (P less than .005) or helper and cytotoxic T-lymphocyte-depleted mice (P less than .001) than in non-MoAb-treated mice. However, a progressive increase in the number of mice with hyperglycemia ensued in all MoAb-treated groups, and 2 mo after STZ was administered, the prevalence of hyperglycemia, mean plasma glucose levels, and pancreatic insulin contents did not differ significantly from the values obtained in the non-MoAb-treated animals. Similarly, STZ-injected C57BL/6J male nude mice developed hyperglycemia that was associated with a marked decrease in pancreatic insulin contents on a time course comparable with that of STZ-injected euthymic C57BL/6J male mice depleted in helper or in helper and cytotoxic T-lymphocytes by MoAbs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Conditions for thiamin assay by cyanogen bromide oxidation.

Optimum conditions for the assay of thiamin were studied using a cyanogen bromide (BrCN) oxidation method. The adopted procedure included neither pre-purification of samples through an ion exchanger nor extraction of the thiochrome into an organic solvent. The 0.25 M BrCN (the concentration before the addition of alkali) and the final NaOH concentration of approx. 1% gave the highest yield of thiochrome by a laboratory-prepared BrCN. To obtain the highest intensity of fluorescence, a concentrated BrCN (1.8 M) was introduced in place of the conventional BrCN (0.11 M), obtaining 300% or more intensity of fluorescence. For the oxidation of thiamin diphosphate, 0.15-0.2 M of laboratory-prepared BrCN gave the highest intensity of fluorescence instead of the 0.25 M for free thiamin. For simultaneous oxidation of free thiamin and thiamin diphosphate, therefore, 0.23-0.24 M of laboratory-prepared BrCN was deduced to give the best yield of fluorescence. With a solution of commercially obtained solid CNBr, optimum concentrations for the oxidation of thiamin were about 0.04 M for CNBr and about 0.16% for NaOH. When the sample contained in inhibitor of oxidation, such as ascorbic acid, the percentage of inhibition decreased inversely proportional to the concentration of the sample in a rough approximation. The degree of inhibition was not reduced by the increased amount of BrCN reagent. Thus the possibility was indicated that thiamin in an ascorbic acid-contaminated sample could be determined accurately by extrapolating values for serially diluted samples.

Ascorbic Acid↗
PubMed1988

Resistance to tolerance induction to human gammaglobulin (HGG) in autoimmune BXSB/MpJ mice: functional analysis of antigen-presenting cells and HGG-specific T helper cells.

Autoimmune male, but not female, BXSB/MpJ mice resist the induction of tolerance to human gammaglobulin (HGG). To better define the cellular basis for this abnormality, we have compared in vitro the functional activity of antigen-presenting cells between tolerant-resistant male and susceptible female mice, and evaluated in vivo the immunological status of HGG-specific T helper cells in male BXSB mice after the treatment with monomeric deaggregated HGG (DHGG). Our results indicated that there were no significant differences in the ability of male and female antigen-presenting cells to present HGG to either male or female HGG-specific immune T blasts. Further, thymic cells from DHGG-treated male BXSB mice failed to support anti-HGG antibody responses when adoptively transferred with non-treated bone marrow cells, and that draining lymph node cells from male as well as female BXSB mice treated with DHGG prior to the challenge of immunogenic aggregated HGG (AHGG) were unable to exhibit the proliferation upon in vitro restimulation with AHGG. This indicates that HGG-specific T helper cells were indeed tolerized in tolerant-resistant male BXSB mice by the treatment with DHGG. In contrast, when the tolerance induction was inhibited by bacterial lipopolysaccharides, HGG-specific T helper cells from such mice exhibited a marked proliferation upon in vitro restimulation with AHGG. These results suggest that the cellular defect in the abnormal resistance to tolerance induction to HGG in male BXSB mice resides neither in the antigen-presenting cells nor in the HGG-specific T helper cells, and that the mechanism responsible for this abnormality in male BXSB mice is basically different from that involved when tolerance is overcome by lipopolysaccharide.

Animals↗
PubMed1988

[A case of colon cancer with pulmonary metastasis treated effectively by uracil futraful].

A 57-year-old female was admitted for advanced ascending colon cancer with a solitary pulmonary metastasis measuring 1.5 cm in diameter. As laparotomy revealed an absolute noncurable tumor of stage V (H0, p2, s2 n1 (+], palliative right hemicolectomy was performed. A pathological diagnosis of well differentiated adenocarcinoma was made postoperatively. A daily dose of 400 mg of UFT was given orally. After 8 months, plain chest film and tomography revealed a reduction in the size of the pulmonary metastasis to 1.0 cm in diameter. The metastatic lung tumor was controlled for a period of 1 year and 9 months. It was suggested that UFT was rather effective for pulmonary metastasis from colon cancer.

Adenocarcinoma↗
PubMed1988

Quantitative analysis of integrated Ed alpha gene expression in C57BL/6 transgenic mice.

We performed quantitative analysis of Ed alpha gene expression in the transgenic mice, created by microinjecting cloned Ed alpha gene fragments into C57BL/6 fertilized eggs. DNA dot-blot analysis revealed that Ed alpha gene-introduced transgenic mice (B6Ed alpha transgenic mice) contain 20 copies per cell of the Ed alpha gene in their genome. RNA dot-blot analysis revealed that the amount of Ed alpha mRNAs in B6Ed alpha transgenic spleen cells is 20-40-fold higher than those in normal BALB/c or (BALB x C57BL/6)F1 (CBF1) spleen cells. However, the amount of Ed alpha molecules expressed on B6Ed alpha transgenic spleen cells was similar to that expressed on normal BALB/c of CBF1 spleen cells on a gene-dose basis. The amount of endogenous Ed alpha mRNA in the B6Ed alpha transgenic spleen cells was almost equal to that of normal B6 spleen cells. Since the cell surface I-E molecule is formed by non-covalent association of E alpha and E beta chain, these results suggest that, in spite of the high expression of integrated Ed alpha gene in the cytoplasm of B6Ed alpha transgenic mice, the amount of Ed alpha gene expression on the cell surface is limited by the amount of endogenous Eb beta gene products.

Animals↗
PubMed1987

Occurrence of a new enzyme catalyzing the direct conversion of NG,NG-dimethyl-L-arginine to L-citrulline in rats.

An enzyme concerned with the degradation of NG,NG-dimethyl-L-arginine to L-citrulline was investigated in rats. The enzyme purified from rat kidney catalyzed the direct conversion of NG,NG-dimethyl-L-arginine to L-citrulline with liberation of dimethylamine from the methylated guanidino moiety. The reaction required no co-factor and the maximum activity was obtained at pH 6.5. The enzyme was highly specific for NG,NG-dimethyl-L-arginine.

Amidohydrolases↗
PubMed1987

Molecular studies on thiaminase I.

The thiaminase I gene of Bacillus thiaminolyticus was cloned on a 1.6 kb DNA fragment (enzyme molecular weight 42,000), and was expressed in both Escherichia coli and Bacillus subtilis. When a selection drug was absent, the plasmid was maintained stably for approx. 100 generations in wild-type E. coli. Instability of the thiaminase gene was demonstrated in the thiamin pyrophosphate-requiring mutant of E. coli from which the plasmid was deleted rapidly. Wild-type E. coli accumulated the enzyme in its periplasm. A method for the detection of thiaminase I enzyme in SDS-polyacrylamide gel was developed. Thiaminase I of B. thiaminolyticus was found to exist in two sizes, 44 and 42 kDa, among different strains. Moreover, thiaminase of 42 kDa became approximately 41 kDa after a long-term culture, most likely because of the action of proteinases. Thiaminase expressed in E. coli from a thiaminase-positive recombinant plasmid was 42 kDa, and showed the same mobility on SDS-polyacrylamide gele electrophoresis as the enzyme isolated from the young culture of the parent strain of B. thiaminolyticus used for cloning. This value was, therefore, considered to represent intact thiaminase that had escaped from the attack of bacilli proteinases.

Alkyl and Aryl Transferases↗
PubMed1987

Metabolism of NG,NG-and NG,N'G-dimethylarginine in rats.

The metabolic fates of NG,NG-and NG,N'G-dimethylarginines in rats were investigated isotopically and novel metabolites, alpha-keto-delta-(N,N-dimethylguanidino)-and alpha-keto-delta-(N,N'-dimethylguanidino)valeric acids and gamma-(N,N-dimethylguanidino)-and gamma-(N,N'-dimethylguanidino)butyric acids were identified. In the case of the rats injected with NG,NG-dimethyl-L-[1,2,3,4,5-14C]arginine, about 13% of the radioactivity was recovered in the first 12-h urine and was distributed in the following metabolites (relative ratios): unchanged NG,NG-dimethyl-L-arginine (35.2%), gamma-(N,N-dimethylguanidino)butyric acid (18.4%), alpha-keto-delta-(N,N-dimethylguanidino)valeric acid (16.4%), and N alpha-acetyl-NG,NG-dimethyl-L-arginine (8.5%). The radioactivity retained in the tissues was found mainly in citrulline and was further distributed in ornithine, arginine, and glutamic acid and even in protein-bound arginine. In the case of NG,N'G-dimethyl-L-[1,2,3,4,5-14C]arginine-injected rats, about 75% of the radioactivity was excreted in the first 12-h urine and was recovered in the following metabolites (relative ratios): N alpha-acetyl-NG,N'G-dimethyl-L-arginine (48.4%), unchanged NG,N'G-dimethyl-L-arginine (23.7%), alpha-keto-delta-(N,N'-dimethylguanidino)valeric acid (20.2%), and gamma-(N,N'-dimethylguanidino)butyric acid (9.6%). In the tissues, most of the radioactivity was associated with unchanged NG,N'G-dimethyl-L-arginine. These findings show that both dimethylarginines are metabolized by a pathway forming the corresponding alpha-ketoacid analogs and the oxidatively decarboxylated products of the alpha-ketoacids in addition to the N alpha-acetyl conjugates identified previously (K. Sasaoka, T. Ogawa, and M. Kimoto (1982) Arch. Biochem. Biophys. 219, 454-458), and NG,NG-dimethyl-L-arginine is catabolized by an additional pathway leading to the formation of citrulline and its metabolically related amino acids. By considering their catabolism, an attempt to use urinary dimethylarginines as an index of in vivo breakdown of tissue proteins is invalid at least in rats.

Animals↗
PubMed1987

Nucleoside-triphosphatase and hydrolysis of thiamin triphosphate in Escherichia coli.

A membrane-bound nonspecific triphosphatase of E. coli was solubilized and purified to a homogeneous SDS-acrylamide gel electrophoresis band. It was found to be a single polypeptide of 16 kDa requiring no Mg2+, with an optimal pH at 6.5. The substrate specificity was broad and a nonspecific Mg2+-independent ribonucleoside-triphosphatase (NTPase) activity was expressed together with thiamin-triphosphatase activity. The molecular size and characteristics were clearly different from the known NTPase (EC 3.6.1.15). Using the purified thiamin-triphosphatase II, ATP:thiamin-diphosphate phosphoryl transferase (EC 2.7.4.15) activity was demonstrated with an optimal pH of approx. 5.3. Considering its kinetic parameters and other characteristics, however, the thiamin triphosphate synthesizing activity was not thought to take part in cellular thiamin triphosphate synthesis. The possibility that thiamin-triphosphatase II plays a part in the hydrolysis of thiamin triphosphate to control its cellular level is suggested.

Cell Membrane↗
PubMed1987

Benign renal angiomyolipoma with regional lymph node involvement. Report of a case showing enlargement five years after nephrectomy.

A case of renal angiomyolipoma followed by massive enlargement of the angiomyolipoma in regional lymph nodes five years after nephrectomy is reported. On the basis of its histology and the absence of distant metastasis, we considered this to be a benign, hamartomatous, and multicentric lesion. Considering the rather rapid growth, however, this case raises some questions with regard to the treatment of this condition, i.e., whether removal of a renal angiomyolipoma should be accompanied by lymphadenectomy, and whether the lymph nodes should be carefully scrutinized by CT scanning or echography preoperatively.

Adult↗
PubMed1987

[Effects of intravenous feeding on adjuvant chemotherapy--an experimental study on the distribution of 5-FU after injection of tegafur (1)].

Forty-eight male Donryu rats inoculated with Sato lung cancer were used to experimentally determine the effects of intravenous feeding on the concentrations of the chemotherapeutic agents FT-207 and 5-FU in the blood, as well as in the liver and tumorigenic tissue. Following FT-207 administration, the blood, tumor and liver tissue levels were lower than in the IVH group (oral administration). The liver 5-FU concentration, at 0.10 +/- 0.02 microgram/g, was significantly higher in the intravenous feeding group than in the p.o. group (0.05 +/- 0.01 micrograms/g). The 5-FU blood concentration rose quickly, reaching 0.051 +/- 0.013 micrograms/ml and 0.035 +/- 0.004 micrograms/ml at 9 and 12 hours, respectively, following treatment. This was significantly higher than in the p.o. group, which showed corresponding levels of 0.031 +/- 0.004 microgram/ml and 0.022 +/- 0.002 microgram/ml, respectively. The increase in the 5-FU level within the tumor was markedly high in the IVH group compared to the p.o. group, and it peaked at 9 hours following administration. The concentration in the IVH group was thus higher than in the p.o. group at any given time. At 24 hours after treatment, the IVH group level was 0.35 +/- 0.09 microgram/g, against 0.27 +/- 0.05 microgram/g in the p.o. group. The blood concentration of 5-FU following intravenous feeding maintained a high value for a long time, and the 5-FU tumor concentration also remained at a high level. The intravenous route was therefore considered to be advantageous for antitumor chemotherapy.

Animals↗
PubMed1987

[Serum concentration of 5-FU and tegafur (FT-207) after administration of tegafur (FT-207) suppository with the colostomy].

Tegafur (FT-207) suppositories were administered at a rate of 750 mg via the artificial anus (ST Group) following surgery of rectal cancer. Comparative studies were conducted of changes in blood concentrations of 5-FU and tegafur at the time of initial administration and following one week of continuous use for the low-anterior resection cases (LA Group) and the rectal administration cases (RE Group). FT-207 concentration at initial administration was low in the ST group compared to those for both LA and RE groups which received anal administration of the drug, but only little changes were noted. Blood concentration one hour after administration was 11.1 micrograms/ml, elevated to 14.3 micrograms/ml at two hours, and remained at 10 micrograms/ml and above for six hours following administration. The ST group 5-FU concentrations at two, four and six hours after administration were significantly lower than those in the RE group but the changes were little. Blood concentrations were 0.015 microgram/ml at one hour after administration, 0.017 micrograms/ml at two hours and maintained virtually the same level thereafter. An effective concentration of 0.012 microgram/ml was maintained even at ten hours following administration. After one week of administration of the suppositories, the ST group showed the lowest concentration among three groups, but it was approximately double compared to the initial concentration; FT-207 showed nearly the same concentration in the LA group and 5-FU blood concentration was 0.025 microgram/ml at one hour after administration, reached to a maximum of 0.030 microgram/ml at two hours and maintained 0.020 microgram/ml and higher at ten hours. 5-FU concentration in the LA and RE groups after one week of continuous administration showed a dual-peaked pattern. No patient with an abnormal artificial anus was involved in this study. The artificial anus is thought to be an adequate and effective administration route of FT-207 suppositories.

Adult↗
PubMed1987

[Effects of intravenous alimentation on adjuvant chemotherapy--an experimental study on the distribution of 5-FU after injection of tegafur (2)].

The stomach, small and large intestines, heart, lungs, bone and kidneys were removed from 48 Sato lung cancer-bearing rats used in the previous experiments and given 90 mg/kg of tegafur (FT-207) by single intravenous administration and tissue 5-FU and FT-207 concentrations were measured. FT-207 concentration in the alimentary canal was somewhat lower than the blood concentration, but both were lowered in parallel. 5-FU concentration in the stomach and large intestines showed virtually identical changes in both IVH and PO groups, but IVH group tended to have higher concentration. IVH group showed higher values than PO group anytime, particularly in the large intestines. A reduction of the side effects on the digestive system via intravenous alimentation was thought due to the elimination of mechanical stimulation via a cessation of oral feeding. 5-FU concentration in the bone was highest in PO group at six hours after administration and blood concentration changes were parallel, but there was virtually no change in IVH group. Maximum values were found one hour after administration and slowly declined thereafter; at 24 hrs the values were 0.059 +/- 0.013 microgram/g, relatively high compared to the PO group at 0.041 +/- 0.022 microgram/g. In the present study under intravenous alimentation, the concentration changes were slight in spite of 5-FU maximum concentration being lower than that by oral feeding and the long-term high concentration which was maintained; this is thought to be a disadvantageous action with regard to the bone marrow. FT-207 concentration in the kidney, heart and lungs was the same as that for the blood, with a gradual reduction in IVH group. 5-FU concentration was the same for the kidneys and IVH group quickly reached to the high levels compared to PO group with only slight changes thereafter. Effects of continuous water load might be involved but not clear.

Animals↗
PubMed1986

Alteration of the T cell self-specificity repertoire by treatment with anti-Ia antibody during embryonic life.

The effect of anti-Ia antibody on the development of murine neonatal self-Ia-reactive T lymphocytes in the thymus was studied. A C57BL/6 (B6) mouse pregnant with (B6 X C3H/He)F1 (B6C3F1) embryos was injected with monoclonal anti-I-Ek (m alpha I-Ek) antibody every other day starting from the 12th day of gestation. The mixed leukocyte culture reaction (MLR) responses of thymocytes from m alpha I-Ek-treated neonatal mice were assayed against adult B6 (H-2b), C3H/H3 (H-2k) or BALB/c (H-2d) splenic stimulator cells. The syngeneic MLR response of m alpha I-Ek-treated B6C3F1 neonatal thymocytes against C3H stimulator cells was augmented compared to that of untreated neonatal thymocytes. Experiments utilizing recombinant inbred strains of mice as well as monoclonal anti-Ia antibody blocking experiments suggested that the antigen(s) responsible for this augmentation of syngeneic MLR resided in the I-Ek molecule. The MLR response against B6 or BALB/c stimulator cells was not influenced by m alpha I-Ek treatment. We speculate that m alpha I-Ek antibody blocked the expression of I-Ek molecules in B6C3F1 embryos and this resulted in the alteration of T cell self-specificity repertoire in the thymus. Our results support the concept that Ia molecules play important roles for the elimination of self-reactive T lymphocyte clones in the thymus.

Animals↗