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K Arai

Publications and source records attributed to K Arai.

At least 19 recordsLinked to original sources
PubMed1992

The carboxyl terminus of RAP30 is similar in sequence to region 4 of bacterial sigma factors and is required for function.

Transcription factor beta gamma (RAP30/74) from rat liver was previously shown in biochemical studies to control the binding of RNA polymerase II to promoters by a mechanism analogous to that utilized by bacterial sigma factors, by decreasing the affinity of polymerase for nonpromoter sites on DNA and by increasing the affinity of the enzyme for the preinitiation complex (Conaway, R. C., Garrett, K. P., Hanley, J. P., and Conaway, J. W. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 6205-6209). By constructing and analyzing mutants of beta gamma, we have identified a novel functional domain located in the carboxyl terminus of the gamma (RAP30) subunit. This domain shares sequence similarity with region 4 of bacterial sigma factors; in particular, it exhibits striking similarity to the carboxyl-terminal regions 4.1 and 4.2 of SpoIIIC (Bacillus subtilis sigma k). Evidence from biochemical studies argues that a mutant gamma (RAP30), lacking amino acid sequences similar to sigma homology region 4.2, is able to assemble with the beta (RAP74) subunit to form a mutant beta gamma (RAP30/74) with impaired ability to interact with RNA polymerase II.

Amino Acid Sequence↗
PubMed1992

Protein kinase C mutants in the auto-inhibitory region exhibit two distinct properties.

To define the role of the auto-inhibitory region of protein kinase C (PKC), Arg22-Lys23-Gly24-Ala25-Leu26-Arg27, site-directed mutations were introduced into the basic residues. Three mutants, PKCAla22,23, PKCAla27, and PKCAla22,23,27, apparently fell into two distinct types with regard to their biochemical properties and biological activities, as judged by the enhancement of a c-fos promoter in Jurkat cells and by the initiation of germinal vesicle breakdown (GVBD) in Xenopus laevis oocytes. (i) PKCAla22,23 and PKCAla27 had activators independent in vitro kinase activity, high phosphorylation levels in vivo, and localized in both cytosolic and particulate fractions. These mutants were not fully biologically active. (ii) PKCAla22,23,27 had a low phosphorylation level in vivo, was found predominantly in the particulate fraction and was the most biologically active. These results suggest that basic residues in the auto-inhibitory domain account for the regulation of kinase activity and the cytosolic retention of PKC. The particulate association or the cytosolic clearance of PKC may facilitate signal transduction in the cell.

Amino Acid Sequence↗
PubMed1992

Differences in the enzymatic nature and the sugar-chain structure of gamma-glutamyl transferase between normal and carcinomatous human kidney and prostate.

The enzymatic and immunological nature, and the sugar chain structure, of gamma-glutamyl transferase (GGT) purified from tissues of benign prostatic hypertrophy (BPH), prostatic carcinoma (PCa) and renal cell carcinoma (RCa), were compared with those of the normal prostate (NP) and kidney (NK). The specific activities of GGTs in NP, NK, BPH, PCa and RCa were 78.9, 22.5, 105, 92.5 and 52.5 mU/mg protein, respectively. The molecular masses of GGTs from BPH, PCa and RCa were 72 kDa, 78 and 108 kDa, and 79 and 105 kDa, respectively. The Michaelis constants (Km), optimum pHs and the inhibition of GGT activities by several chemical compounds, revealed that the GGT from BPH, PCa and RCa was similar to that of normal GGT. Immunologically, the IgG fraction against anti-human seminal plasma GGT fused to the all of the GGTs tested. The sugar chain heterogeneities of the various GGTs, detected by the serial-lectin affinity technique, differed from one another. The sugar chain of GGT from BPH resembled the sugar chain from NP. On the contrary, the sugar chains of GGTs from PCa and RCa were markedly different from those from normal tissues. In the GGT from PCa, multi-antennary complex type sugar chains were more increased than the enzyme of NP. In general, as previously reported, the sugar chains of GGTs from carcinomatous tissues of prostate and kidney had an increased content of bisecting GlcNAc (beta 1-->4) containing complex type sugar chains. Moreover, the reductions of the biantennary complex type sugar chain with fucose linkage and the hybrid type sugar chain were obvious in the GGT from carcinomatous tissues of the prostate and kidney.

Adult↗
PubMed1992

Molecular cloning of rabbit CAP-50, a calcyclin-associated annexin protein.

CAP-50 is a member of annexin family proteins which binds specifically to calcyclin in a Ca2+ dependent manner (Tokumitsu. H., Mizutani. A., Minami. H., Kobayashi. R., and Hidaka. H. (1992) J. Biol. Chem. 267,8919-8924). The cDNA representing the rabbit form of this protein has been cloned from rabbit lung cDNA library. Sequence analysis of two overlapping clones revealed a 81-nucleotides 5'-nontranslated region, 1512-nucleotides of open reading frame, a 672-nucleotides 3'-nontranslated region, and a poly(A) tail. Authenticity of the clones was confirmed by comparison of portions of the deduced amino acid sequence with eight sequences of proteolytic peptides obtained from rabbit lung protein. CAP-50 cDNA encodes a 503 residue protein with a calculated M(r) of 54,043 and shows that the protein is composed of four imperfect repeats and hydrophobic N-terminal region. C-terminal region including four imperfect repeats shows 58.1% identity with human synexin (annexin VII), 48.0% identity with annexin I, 47.4% identity with annexin II, 60.1% identity with annexin IV, 54.5% identity with annexin V. Hydrophobic N-terminal region composed of 202 amino acid residues is not homologous with other annexin proteins suggesting that CAP-50 is a novel member of annexin family proteins.

Amino Acid Sequence↗
PubMed1992

Pyrogenic action of endothelin in conscious rabbit.

Injection of 0.3 nmol/kg endothelin(ET)-1 into the ear vein of conscious rabbits induced a significant increase in body temperature. ETB receptor specific agonist, namely 4-Ala-ET-1, also caused an elevation of the body temperature in a dose-dependent manner by injection into the ear vein of rabbit. These results suggest that ET play important roles in regulation of body temperature through selective stimulation of ETB receptor.

Analysis of Variance↗
PubMed1992

Calreticulin is present in the acrosome of spermatids of rat testis.

We have already succeeded in purifying a calcium-binding protein (CalBP) from rat spermatogenic cells [Nakamura et al., Biochem. Biophys. Res. Commun., 176 (1991) 1358]. In this study, the location of this protein within rat testis was examined, using a rabbit antisera for this protein. The antigen was localized on the developing acrosomes during spermiogenesis. The NH2-terminal amino acid sequence obtained for rat CalBP was identical to that of calreticulin obtained for the skeletal muscle of mice and closely resembled that for rabbit calreticulin. On the immunoblot analysis, the purified rat CalBP reacted with an antibody raised against rabbit skeletal muscle calreticulin. The results indicate that calreticulin is present in the acrosome of spermatids of rat testes.

Acrosome↗
PubMed1992

Antisera to calreticulin inhibits sperm motility in mice.

Mouse sperm were rapidly immobilized when exposed to rabbit antisera against rat calreticulin. The inhibition of sperm motility was concentration dependent at dilutions 1:50-350. The velocity of sperm did not change significantly as long as they were motile. Neither motility nor velocity of sperm was affected by adding sheep antisera to bovine calmodulin. The antisera to calreticulin also inhibited in vitro fertilization of mouse eggs. Using the avidin-biotin-peroxidase complex method, the antigen was found to be localized in the acrosome of sperm. The results indicate that calreticulin is present in the acrosome of mouse sperm and may play an important role in sperm motility.

Animals↗
PubMed1992

Stimulation of mouse connective tissue-type mast cells by hemopoietic stem cell factor, a ligand for the c-kit receptor.

The proliferative capacity of mouse connective tissue-type mast cells (CTMC) was analyzed by using a newly discovered c-kit ligand, termed stem cell factor (SCF). More than 90% of CTMC in the peritoneal cavity responded to recombinant rat SCF (rrSCF) and were able to give rise to pure mast cell colonies in methylcellulose culture. Serial observation (mapping) of growth of individual CTMC in culture containing rrSCF confirmed their striking proliferative ability. No serum but accessory cells (non-CTMC cells) in the peritoneal population were required for the clonal growth of CTMC induced by rrSCF in our methylcellulose culture of whole peritoneal cells. The rrSCF-induced mast cell colony formation from peritoneal CTMC was completely inhibited by the addition of anti-c-kit antibody, which can block the binding of SCF to c-kit, to the culture. When IL-3 was combined with rrSCF, mast cell colonies dramatically increased in size. Mapping studies revealed that the combination of the two factors augmented the proliferative rate of CTMC. Approximately 60% of the constituent cells of the mast cell colonies which were formed from peritoneal CTMC in the culture containing rrSCF alone were stained with berberine sulfate, which is a characteristic of CTMC. However, most mast cells which were induced by rrSCF+IL-3 from peritoneal CTMC contained berberine(-)-safranin(-)-Alcian blue(+) granules. Although IL-4 exhibited little synergism with rrSCF in the induction of CTMC proliferation, the addition of IL-4 to the culture containing rrSCF+IL-3 resulted in an increase in mast cells which retained CTMC characteristics.

Animals↗
PubMed1992

An 11-base-pair DNA sequence motif apparently unique to the human interleukin 4 gene confers responsiveness to T-cell activation signals.

We have identified a DNA segment that confers responsiveness to antigen stimulation signals on the human interleukin (IL) 4 gene in Jurkat cells. The human IL-4 gene, of 10 kilobases, is composed of four exons and three introns. A cis-acting element (P sequence) resides in the 5' upstream region; no additional DNA segments with enhancer activity were identified in the human IL-4 gene. For further mapping purposes, a fusion promoter was constructed with the granulocyte/macrophage colony-stimulating factor basic promoter containing 60 base pairs of sequence upstream from the cap site of the mouse granulocyte/macrophage colony-stimulating factor gene and various lengths of the 5' upstream sequence of the IL-4 gene. The P sequence was located between positions -79 and -69 relative to the transcription start site of the human IL-4 gene, and this location was confirmed by base-substitution mutations. The plasmids carrying multiple copies of the P sequence showed higher responsiveness to the stimulation. The binding protein(s) that recognize the P sequence of the IL-4 gene were identified by DNA-mobility-shift assays. The binding of NF(P) (a DNA binding protein that specifically recognizes the P sequence) to the P sequence was abolished when oligonucleotides carrying base substitutions were used, indicating that the NF(P) interaction is sequence-specific and that binding specificity of the protein paralleled the sequence requirements for IL-4 expression in vivo. The P sequence does not share homology with the 5' upstream sequence of the IL-2 gene, even though surrounding sequences of the IL-4 gene share high homology with the IL-2 gene. We conclude that a different set of proteins recognize IL-2 and IL-4 genes.

Animals↗
PubMed1992

[Doppler sonography in the diagnosis of liver tumors].

The value of color duplex Doppler sonography in evaluating tumor vascularity was investigated in 82 hepatic tumors (61 hepatocellular carcinomas, 11 metastatic cancers, eight adenomatous hyperplasia, one focal nodular hyperplasia, and one cholangiocellular carcinoma) receiving angiography, 64 intrahepatic arteries, and five hepatic cysts. The minimum diameter of the intrahepatic arteries (lateral inferior subsegmental arteries) from which signals could be weakly obtained by using a 3.5 MHz transducer was 0.7 mm. Twenty-eight (74%) of 38 tumors with signals within them had definite tumor vessels on angiography, and continuous blood flow within the tumors showed an association with the dilated tumor vessels. Eighteen (69%) of 26 tumors with signals within them receiving conventional angiography had tumor vessels greater than 0.7 mm. However, only 17 (31%) of 55 tumors less than or equal to 3 cm showed signals within them in contrast to 21 (78%) of 27 tumors greater than 3 cm. Three of eight adenomatous hyperplasias, which were angiographically undetected and had portal or hepatic venous branches, showed signals within them. Four tumors that had abnormally high velocity arterial signals (greater than 0.63 m/sec) within them showed no arteriovenous shunt. Evaluation of tumor vascularity according to the Doppler sonographic findings at the periphery of the tumor was difficult. This was attributed to the fact that the real sample volume was larger than that on B-mode image, with no correlation seen between the signals at the tumor periphery or the existence of arteries surrounding the tumor and tumor vascularity. Although a correlation was seen between tumor vascularity or tumor size and peak systolic velocity determined at the tumor periphery (p less than 0.05), five of six tumors with abnormally high velocities (greater than 0.63 m/sec) at the tumor periphery were greater than or equal to 5 cm in diameter. Doppler signals of the artery feeding the arteriovenous shunt were characterized by abnormally high velocity and low resistive index. In conclusion, Doppler sonography is somewhat useful in evaluating tumor vascularity, but less so in small hepatic tumors.

Adult↗
PubMed1992

Characterization of immunoreactive endothelin in human urine.

We developed three antibodies, specific and sensitive to endothelin-1 (ET-1), and established two sandwich and three competitive enzyme immunoassays (EIAs). By using these EIAs, large immunoreactive ET (IR-ET) of molecular weight 10 k Da was identified as a main component of IR-ETs in human urine. This large IR-ET, which reacted with two antibodies specific for N-terminal region of ET-1 but not with the antibody against C-terminal peptide of ET-1, was partially purified by six-step procedure and examined by Western blotting after SDS polyacrylamide gel electrophoresis. The large IR-ET was detected as a single band at molecular weight of 10 k Da both in reduced and non-reduced conditions. From these results, the large IR-ET was thought to consist of a single polypeptide chain and possess the steric restricted N-terminal region of ET-1.

Amino Acid Sequence↗
PubMed1992

Structure of mouse interleukin 3 (IL-3) binding protein (AIC2A). Amino acid residues critical for IL-3 binding.

Despite the high degree of sequence homology between two mouse proteins AIC2A and AIC2B (91% at the amino acid level), only the AIC2A protein binds interleukin 3 (IL-3). Soluble AIC2A protein bound IL-3 with affinity similar to the membrane-bound AIC2A protein, indicating that binding of IL-3 to AIC2A was mediated by the external domain alone. The extracellular domain of the AIC2A protein has two repeats of the common motif shared by members of the cytokine receptor family. Neither one of these repeats alone bound IL-3. Hybrids of AIC2A and AIC2B revealed that the first domain of the cytokine receptor motif could be replaced with the AIC2B sequence without an affinity change, suggesting the importance of the second domain. By changing individual amino acid residues of AIC2A in the second domain which differ from those of AIC2B, we identified several amino acid residues critical for IL-3 binding. All these residues are located at the putative hinge region within the second domain.

Amino Acid Sequence↗
PubMed1992

Effect of local tumor removal and retained oncolysate on lung metastasis.

We reported earlier that oncolysate retained in the excision wound of a local tumor inhibits growth of remote tumor in the rat. We further studied this effect on pulmonary metastasis. C57BL/6 mice were given B16 melanoma F10 cells subcutaneously into the gluteal area (Day 0) and then intravenously on Day 10. On Day 14, mice were divided into four groups. Group 1 received a sham operation and no further treatment. Tumors were excised in the remaining mice. Group 2 received tumor excision alone. Groups 3 and 4 received injections of freeze-lysed tumor cells (TC) and lysate modified (PTC) with a hapten, L-phenylalanine mustard (PhM), respectively, into excision wounds. On Day 24, metastases were assessed by determining metastatic burden. Average diameters of excised tumors in repeated experiments ranged from 8.7 to 10.9 mm. In repeat experiments, pulmonary metastatic burden increased by as much as 52 to 181% in the tumor excised group (Group 2) in comparison with those receiving sham surgery (Group 1). However, metastatic burden was always reduced in Group 3. An even greater reduction was seen in Group 4. To study the possible involvement of macrophages, the production of prostaglandin-E2 (PGE2) and cytotoxicity of macrophages in these animals were examined. It was found that tumor excision enhanced PGE2 production by macrophages and suppressed their cytotoxicity, while TC inoculation prevented both of these changes. An even greater prevention was observed with PTC inoculation. These results indicate an association among macrophage cytotoxicity, PGE2 production of macrophages, and metastasis. In order to clarify the mechanism for these reactions, we did experiments using adherent splenic macrophages from the four groups of animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Use of mammalian cell expression cloning systems to identify genes for cytokines, receptors, and regulatory proteins.

Mammalian cell expression cloning has become a standard technique for the isolation of mammalian genes or cDNAs. Its advantage is that the biological functions of the gene of interest are used for cloning. Therefore, the identified cDNAs or genes should be functional in vivo, and there is no need for physical or chemical information about the gene products, so that protein purification in sufficient quantity to raise antibodies or to obtain amino acid sequences is not necessary. Here, we summarize recent progress in mammalian cell cloning systems, and discuss the possible directions in which this technique will lead.

Animals↗
PubMed1992

Nasal reconstruction with a thin, free flap prefabricated with a silicone sheet: case report.

When the reconstruction of facial tissue requires the use of a flap, this is best carried out with a thin flap that matches the texture of facial skin. For this reason, the authors often use postauricular and subclavicular donor sites. In the reported case, a prefabricated flap was created in the patient's subclavicular skin, by utilizing a silicone sheet and transferring the thoracodorsal vessels. Two weeks after the procedure, this prefabricated flap was transplanted with microsurgical techniques, to reconstruct the ala nasi, after a limited resection of a cavernous hemangioma that preserved the alar cartilage. A very favorable outcome was achieved.

Adult↗
PubMed1992

Comparison of clinical usefulness of very-low-calorie diet and supplemental low-calorie diet.

Forty-five overweight patients (12 male, 33 female) were prescribed a very-low-calorie diet (VLCD) or a supplemental low-calorie diet (LCD), randomly, at an outpatient clinic. Twenty obese patients [31.6 +/- 13.1 y; body mass index (BMI) 32.9 +/- 6.1] were treated with a VLCD of 1757 kJ/d for 1-2 mo (five packages of Optifast 70/d; Sandoz Nutrition, Minneapolis). Another 25 patients (35.3 +/- 11.7 y; BMI 31.9 +/- 4.4) were treated by a supplemental LCD of 3515-5021 kJ/d for 1-2 months, which consisted of two to three packages of Optifast 70 and 2678-3682 kJ of conventional balanced meals. By the fourth week, the weight reduction obtained by the VLCD was significantly greater than that achieved by the supplemental LCD (P less than 0.01). At the eighth week, however, effect of the VLCD and the supplemental LCD in terms of weight reduction did not differ significantly. No serious side effects were observed in either treatment group. However, remarkable elevation of serum uric acid concentration was detected in seven patients on the VLCD. The treatment period of the VLCD is limited to less than or equal to 3 mo. On the other hand, obese patients can be treated with the supplemental LCD for greater than 3 mo. Therefore, the supplemental LCD is considered to be useful in the treatment of moderately obese Japanese patients on an outpatient basis.

Adult↗
PubMed1992

A case of giant cell tumor of the parotid gland.

In this study, we report a recent patient with a giant cell tumor located in the parotid gland. This condition appears to be very rare; there have been only a few reports of similar patients. The origin of the tumor has remained unclear in previous patients, as well as in our present patient, and awaits further investigation.

Giant Cell Tumors↗