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Biomedical subjects

S Katoh

Publications and source records attributed to S Katoh.

At least 253 records · Page 14Linked to original sources
PubMed1990

The complete amino acid sequence of the mature form of rat sepiapterin reductase.

The partial amino acid sequence of rat sepiapterin reductase was determined using peptides generated by cleavage of the S-carboxyamidomethylated protein with Achromobacter protease I, cyanogen bromide, chymotrypsin or BNPS-skatole. The protein began with N-acetyl methionyl residue at the N-terminus and ended with isoleucyl residue at the C-terminus. The present results essentially coincided with the amino acid sequence predicted from the nucleotide sequence of the cDNA recently reported by Citron et al. (Proc. Natl. Acad. Sci. USA 87, 6436-6440 (1990)), clarified the processing event during the biosynthesis and provided the complete amino acid sequence of the mature form of the enzyme.

Alcohol Oxidoreductases↗
PubMed1990

[Clinical usefulness of 67Ga-citrate scintigraphy combined early image in malignant lymphoma--detection of abdominal lesions].

In order to improve the diagnostic accuracy in detecting abdominal lesions of malignant lymphoma, we studied prospectively the usefulness of 67Ga-citrate scintigraphy combined 5 to 6-hour early image with conventional 72-hour delayed image after injection. During the period from July 1986 to September 1988, total 41 67Ga-citrate scintigrams performed on 28 patients with malignant lymphoma (3 Hodgkin's disease, 25 non-Hodgkin lymphoma) were evaluated between early and delayed image regarding to such points as follows; 1) the physiologic bowel uptake of 67Ga-citrate, 2) detection of abdominal lesions indicated by other diagnostic modalities involving computed tomography, lymphography and ultrasonography. Following results were obtained: 1) Prominent bowel uptake of 67Ga-citrate thought to be difficult to interpret the scintigram was observed in only 1 of 41 (2%) on early image versus 13 of 41 (32%) on delayed image. 2) Known lesion sites were detected in 24 of 31 (77%) on early image versus 21 of 31 (68%) on delayed image, resulting in 26 of 31 (84%) in combination with both images. 3) There were 2 false-positive and 5 false-negative lesions. Two false-positive lesions on early image were explained by physiologic hepatic uptake with ill-defined outline and bladder uptake. On the other hand, all of 5 lesions on delayed image were explained by prominent bowel uptake. 4) Two patients were revealed higher splenic uptake comparing with hepatic uptake on both images, later proved to be diffuse splenic involvement without evidence of lesions on other diagnostic modalities. 5) The lesions less than 2 cm in diameter could not be detected in both images.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Neoplasms↗
PubMed1990

Effects of histidine residues on adsorption equilibrium of peptide antibodies.

Histidine and arginine residues in a peptide, which represent residues 112-121 of myoglobin, were replaced by alanine, and antibodies for these peptides were raised in rabbits. Adsorption equilibria between these peptides and antibodies were measured to identify the essential amino acid residues for specific binding and their effects on adsorption behavior. Protonation of one histidine residue affected strongly the dependence of adsorption equilibrium on pH, and the adsorption capacities of the antibodies against the peptides containing this essential histidine residue rapidly decreased at around pH 5-6, which corresponds to the pKa value of histidine. Immunization with peptide sequences containing such histidine residues is one method to obtain suitable antibodies for immunoaffinity chromatography, which have a weak affinity for the elution step under mild conditions.

Adsorption↗
PubMed1990

Identification of sequences responsible for positive and negative regulation by E1A in the promoter of H-2Kbm1 class I MHC gene.

The mechanism of transcriptional regulation of the H-2Kbm1 major histocompatibility complex (MHC) class I gene by adenovirus type 12 E1A (Ad12-E1A) was studied in transfected rat embryonal fibroblasts. Results of long-term expression of the chloramphenicol acetyl transferase (CAT) gene placed under the control of the 5'-flanking region of the mouse MHC class I gene. H-2Kbm1, and the results of nuclear run-on transcription assays, yield evidence for both positive and negative regulation of H-2Kbm1 by E1A gene product. Deletion studies in the H-2Kbm1 promoter region revealed that a proximal 58 bp upstream sequence (-194 to -136, relative to the cap site) and a distal 316 bp sequence (-1837 to -1521) respectively contribute to positive and negative regulation mediated by the E1A gene product. Both regulatory elements of MHC class I gene promoter region are responsible for the differential expression of the H-2Kbm1 gene in Ad12 transformed cells. A nuclear factor binding to the negative element has been detected only in extracts derived from cells expressing Ad12-E1A.

Adenovirus Early Proteins↗
PubMed1990

Effects of surface charges and cholesterol content on amino acid permeabilities of small unilamellar vesicles.

The permeabilities of amino acids through bilayer lipid membranes were determined using small unilamellar vesicles (SUV). Alanine, lysine, arginine, and glutamate show permeabilities on the order of 10(-10)-10(-11) cm/s in the case of SUV prepared from dimyristoylphosphatidylcholine and dicetylphosphate. An increase in the amount of negative charges introduced by dicetylphosphate enhanced the permeability of the positively charged amino acid (i.e., lysine). The permeabilities of net charged amino acids decreased with an increase in cholesterol content, and became less than 10(-12) cm/s with the membrane which consists of equimolar amounts of dimyristoylphosphatidylcholine and cholesterol.

Alanine↗
PubMed1990

67Ga in transferrin-unbound form is taken up by inflamed liver of mouse treated with CCl4.

In order to investigate whether or not transferrin is involved in the uptake of 67Ga by inflamed liver (acute inflammatory tissues) the uptake of 67Ga by the liver of mice treated with carbon tetrachloride (CCl4) was studied. The serum GPT value reached its maximum on the 1st day after the CCl4 treatment. The uptake of 67Ga by the liver also reached its maximum on the 1st day after the CCl4 treatment and the amount uptaken into inflamed liver was about 6 times that uptaken into normal liver. On the other hand, the uptake of 125I-transferrin into inflamed liver on the 1st day after CCl4 treatment was only about 1.6 times that into normal liver. Moreover, cold Fe3+ decreased the uptake of 67Ga by normal liver but increased the uptake of 67Ga by inflamed liver. These results show that transferrin plays an important role in the uptake of 67Ga by normal liver but not by inflamed liver, i.e. 67Ga in the transferrin-unbound form is preferentially taken up by inflamed liver.

Animals↗
PubMed1990

Cause for dark, chilling-induced inactivation of photosynthetic oxygen-evolving system in cucumber leaves.

Effects on oxygen evolution of the storage of detached cucumber (Cucumis sativus) leaves at 0 degrees C in the dark were investigated with thylakoids and oxygen-evolving photosystem II membranes isolated from stored leaves. The cold and dark treatment of leaves selectively inactivated electron transport on the oxidizing side of photosystem II. Photosystem II membranes isolated from treated leaves were largely depleted of two proteins of 20 and 14 kilodaltons, which correspond to the extrinsic 23- and 17- kilodalton proteins of spinach functioning in oxygen evolution. The manganese content of photosystem II membranes was also markedly reduced by the treatment. Thus, the inactivation of oxygen evolution induced by the dark, chilling treatment is ascribed to solubilization of the 20- and 14-kilodalton proteins and extraction of manganese.

Journal Article↗
PubMed1990

Co-culture of human hair follicles and dermal papillae in a collagen matrix.

Human hair follicles, either alone or in combination with dermal papillae, were cultured in a collagen matrix. When plucked hair follicles were cultured alone, spike-like structures composed of outer root sheath cells started growing around the follicle and then radiated into the gel. When isolated dermal papillae were embedded close to the follicles, spikes started growing earlier and grew more rapidly than without the papillae. In cultures of excised follicles from which the dermal papilla had been removed, epithelial cells (possibly hair bulb cells) started growing out from the bulbous portion and then also formed spikes. In the presence of a papilla, the spikes elongated toward the papilla, finally reaching and surrounding it. These findings suggest that dermal papilla cells produce a factor(s) that enhances growth of follicular epithelial cells and also attracts those cells. In cultures of whole excised follicles, two major characteristic patterns of cellular growth were recognized. When the dermal papilla remained inside the bulb in contact with the hair bulb matrix, the hair matrix cells proliferated and differentiated in the normal manner, resulting in elongation of the hair shaft and follicle. But when the papilla was detached from the hair bulb matrix, epithelial cells proliferated from the bulbous portion and finally formed hair follicle-like structures. Thus, attachment of the dermal papilla to the hair bulb matrix in the bulbous portion appears to be necessary for growth of the hair and follicle in the normal manner. Our model may be useful for examining the interaction between follicular epithelial cells and dermal papillae and for studying the growth of hair and follicles in vitro.

Adult↗
PubMed1990

Elevated expression of proto-oncogenes during interleukin-5-induced growth and differentiation of murine B lineage cells.

Interleukin 5 (IL-5), a lymphokine produced by helper T cells, is involved in the regulation of growth and differentiation of B cells and other hematopoietic cells. To elucidate IL-5-mediated intracellular mechanisms, we have established IL-5-dependent and -independent murine early B cell lines, J6 and MJ88-1, respectively, and examined the effect of IL-5 on the expression of proto-oncogenes during proliferation. Two- to 3.5-fold increases in the levels of c-myb, c-myc, c-fos, and c-fms mRNA were observed in J6 cells, compared with those in MJ88-1 cells. Further, a role of IL-5 in the proto-oncogene expression during differentiation was examined by using thymidine-treated murine B-cell chronic leukemia BCL1-B20 cells with growth arrest. After 4-day culture, the amount of IgM secreted from BCL1-B20 cells was augmented 4-6 fold in the presence of IL-5. Although expression of c-myb, c-fos, and c-fms mRNA did not change, only c-myc mRNA expression was elevated within 30 min of stimulation with IL-5 and reached a maximal level by 1 hr. Addition of phorbol 12-myristate 13-acetate (PMA) or IL-4 to the culture of BCL1-B20 cells inhibited both the IL-5-mediated augmentation of IgM secretion and the elevated expression of c-myc mRNA. These findings suggest that the IL-5 signal may be associated with the up-regulation of c-myc expression.

Animals↗
PubMed1990

Double-blind test of human urinary macrophage colony-stimulating factor for allogeneic and syngeneic bone marrow transplantation: effectiveness of treatment and 2-year follow-up for relapse of leukaemia.

A randomized, double-blind placebo-controlled phase III clinical trial was performed to study the effects of human urinary macrophage colony-stimulating factor (hM-CSF) after allogeneic and syngeneic bone marrow transplantation (BMT) in 60 hM-CSF treated and 59 placebo control patients. HM-CSF was administered at a daily dose of 2 x 10(5) units/kg from day 1 to day 14 after BMT. Significant differences between hM-CSF and control patient were found in the recovery time to greater than 0.5 x 10(9) granulocytes/l and the survival rate during the initial 120 d without retransplantation. There was no difference in the incidence or grade of graft-versus-host disease (GVHD). There was no difference in the rate of leukaemic relapse at 24-36 months after BMT in patients with acute lymphocytic, acute nonlymphocytic, or monocytic leukaemia. The results of this trial show that human M-CSF improves the outcome of BMT without any influence on the occurrence of leukaemic relapse or GVHD.

Adolescent↗
PubMed1990

Conversion of normal Ly-1-positive B-lineage cells into Ly-1-positive macrophages in long-term bone marrow cultures.

We obtained eight different cell lines in the long-term bone marrow culture system that showed a germ-line configuration of the joining (J) region segments of the Ig heavy-chain (IgH) genes. Their surface markers were CD45R+, Ly-1+, Lyb-2+, cIgM-, sIgM-, Ia-, Thy-1-, Mac-1-, and IL-2R (Tac)+. Use of very young mice and the presence of IL-5 were important for preferential promotion of the survival of B-lineage lymphocytes bearing the Ly-1 markers. When we treated two of them (J8 and J10) with 5-azacytidine for 24 h followed by co-culture with stromal cells and IL-5, they became Ly-1+, sIgM+ B cells, and Ly-1+, Mac-1+ macrophagelike cells, respectively. After other early lymphoid lines (J1, J8, and J13) were maintained by co-culture with ST2 and IL-5 for more than a year, they showed a heterogeneous DNA rearrangement profile of the J region segment of the IgH gene, although only J13 rearranged the kappa-light chain gene. Northern blot analysis revealed that these cell lines expressed C mu-mRNA, and lambda 5-mRNA, consistent with normal pre-B cells. Intriguingly, J1, J8, and J13 expressed c-fms mRNA constitutively. When J13 cells were co-cultured with ST2 and GM-CSF in place of ST2 and IL-5, they acquired Mac-1 expression and retained Ly-1 expression. They were morphologically macrophages, nonspecific-esterase-positive, and showed phagocytosis of latex beads. These results support evidence for a close relationship between the myeloid and Ly-1+ B-cell pathways of differentiation, and indicate that our IL-5-dependent clones are multipotential intermediates in differentiation from pro-B cells to B cells and macrophages.

Animals↗
PubMed1990

Correlation between levels of plasma adenosine triphosphate and stress to the fetus at delivery.

Adenosine triphosphate (ATP) and its metabolites are released from intracellular stores and levels of ATP in the plasma are affected by hypoxia and by exercise. We examined levels of plasma ATP in the fetus at the time of obstetrical delivery. The arterial (ACB), venous cord (VCB) and maternal venous blood (MVB) samples were collected immediately after clamping of the cord. ATP was determined by the bioluminescence method. The levels of plasma ATP were significantly higher in ACB than in VCB or in MVB. There were significant correlations between the levels of ATP in ACB and in VCB, between the levels in ACB and in MVB and between the levels in MVB and in VCB. In case of delivery by elective cesarean section, the levels of ATP in ACB were significantly higher than those in ACB of the fetus delivered vaginally. We found a significant correlation between the levels of plasma ATP in ACB and PO2 in VCB, though there was no significant correlation between the levels of ATP and pH and PCO2. These observations suggest that ATP in ACB may be of fetal origin, that the levels decrease concomitantly in response to stress during vaginal delivery and correlate with the oxygen supplied from the placenta.

Adenosine Triphosphate↗
PubMed1990

Mechanisms of atrial natriuretic peptide (ANP) secretion by rat hearts perfused in vitro--Ca2(+)-dependent signal transduction for ANP release by mechanical stretch.

Effects of temperature, contraction frequency, and intraatrial pressure on immunoreactive ANP release were investigated in isolated rat hearts perfused in Langendorff or working mode. A reduction of temperature from 37 C to 27 degrees C caused a decrease of ANP release by 64% indicating its marked temperature-dependency (Q10 = 2.92). An increase of atrial contraction frequency from 300 to 500/min in Langendorff-perfused hearts did not cause a significant change in the ANP release. An elevation of left atrial filling pressure of working hearts from 8 to 18 and 28 cmH2O was associated with pressure-dependent, and reversible increase of the ANP release. This pressure-induced release of ANP was inhibited in a low calcium (50% Ca2+) medium or by nifedipine (10(-7) M). N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (W-7, 10(-7)M), a potent calmodulin inhibitor, or ryanodine (10(-8)M) had similar inhibitory action against the pressure-induced increase of ANP release. These results indicate that ANP secretion is primarily regulated by mechanical stretch or distension of the atrial wall, while the atrial contraction frequency is less important as a physiological stimulus for the secretion. The stretch-induced ANP secretion may require an influx of calcium through the voltage-dependent Ca2+ channels. It was also suggested that Ca2+ release from the sarcoplasmic reticulum leading to an activation of calcium-calmodulin kinase may be included in the intracellular processes of ANP release by mechanical stretch.

Animals↗
PubMed1990

[Antigenicity test of mofezolac (N-22)].

Antigenicity studies of mofezolac (N-22) were examined in mice and guinea pigs and the following results were obtained. The findings of active systemic anaphylaxis, passive hemagglutination test, 4 hour passive cutaneous anaphylaxis (4-hr PCA) and 8-day PCA in guinea pigs revealed that N-22 possessed neither immunogenic nor eliciting potentiality. However, N-22 was shown to be eliciting antigenicity in mice when given N-22-ovalbumin conjugate plus Freund's complete adjuvant (FCA) as immunogen.

Anaphylaxis↗
PubMed1990

Inhibition by sodium citrate on 67Ga adsorption to various materials.

The adsorption of 67Ga to the inner surface of stainless steel, polyethylene and silicone tubings was studied. The three tubings remarkably adsorbed 67Ga in order of stainless steel, silicone and polyethylene tubing. Sodium citrate inhibited the adsorption of 67Ga in a dose-dependent manner. These phenomena were also observed in blood sampling via the catheter inserted into the external jugular vein. These results show that constant concentration of sodium citrate is necessary for the in vitro study of 67Ga in order to prevent the adsorption to the surface of experimental materials.

Adsorption↗
PubMed1990

The influences of dexamethasone and indomethacin on 67Ga uptake by normal tissues.

Dexamethasone (DEX) increased 67Ga uptake by the liver and spleen at 4, 8, and even 24 h after the injection of 67Ga. These results showed that DEX influenced 67Ga accumulation as well as the initial entry of 67Ga in the liver and spleen. On the other hand, indomethacin (IM) decreased 67Ga uptake by the liver and spleen at 4 h after the injection of 67Ga but did not influence the uptake at 8 or 24 h after the injection of 67Ga. Moreover, DEX or IM little influenced 67Ga uptake by the kidney and muscle. These results suggest that the influence of DEX or IM on 67Ga uptake or accumulation is specific for the liver and spleen.

Animals↗