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H Ikeda

Publications and source records attributed to H Ikeda.

At least 757 records · Page 42Linked to original sources
PubMed1993

Pro-opiomelanocortin messenger RNA levels in anterior pituitaries of female Wistar fatty rats.

We have studied pro-opiomelanocortin (POMC) gene expression by quantifying the POMC mRNA contents in anterior pituitaries of female Wistar fatty rats, a strain obtained by transfer of the fa gene in Zucker rat to Wistar Kyoto rat, in an attempt to understand the role of ACTH synthesis in altered ACTH and corticosterone secretion in these rats. Five- and 12-week-old female Wistar fatty rats and their lean littermates were examined. Plasma ACTH levels were significantly higher in fatty rats than in lean rats (5 weeks: 114.5 +/- 17.5 pg/ml vs. 54.3 +/- 12.4 pg/ml; 12 weeks: 83.8 +/- 12.3 pg/ml vs. 51.7 +/- 6.8 pg/ml; P < 0.01). There was no significant difference between 5-week-old fatty rats and lean rats in POMC mRNA contents nor in POMC/beta-actin ratios in anterior pituitaries. Twelve-week-old fatty rats, however, had significantly higher POMC mRNA contents and also higher POMC/beta-actin ratios in anterior pituitaries than those in lean littermates (P < 0.01, approximately three-fold difference between lean and obese rats). These data suggest that the difference in POMC mRNA contents between lean and obese rats becomes apparent as they grow and develop obesity and the elevated POMC mRNA levels are at least partly responsible for the increased ACTH secretion in 12-week-old fatty rats.

Adrenocorticotropic Hormone↗
PubMed1993

Radiation therapy for carcinoma of the major salivary glands. Results of conventional irradiation technique.

From January 1967 through November 1991, a total of 135 patients with carcinoma of the major salivary glands (parotid: 95; submandibular: 39; sublingual: 1) were treated at our department. 40 patients had adenocarcinoma, 29 adenoid cystic carcinoma, 24 mucoepidermoid carcinoma and 16 squamous cell carcinoma. 100 patients were irradiated postoperatively and the remaining 35 were treated with radiation alone. Total radiation doses delivered were 50 Gy for the postoperative group and 50 to 66 Gy for the group receiving only radiation using a 60Co single portal with or without wedged paired or single electron portal boost. Actuarial five-year survivals after radiation therapy were 55% for the postoperative group and 26% for radiation only group (p = 0.0004). The local control rates for the postoperative group were 83% for adenocarcinoma, 81% for adenoid cystic carcinoma, 83% for mucoepidermoid carcinoma and 62% for squamous cell carcinoma. Corresponding figures for the radiation only group were 40% for adenocarcinoma, 38% for adenoid cystic carcinoma and 33% for mucoepidermoid carcinoma. Conventional irradiation techniques continue to play an important role because they offer superior local control for postoperative patients with carcinoma of the major salivary glands. However, the local control rates for the radiation only group were only 30 to 40%, so that new irradiation modalities such as provided by a high LET machine are needed for these patients.

Adenocarcinoma↗
PubMed1993

[Isokinetic torque of quadriceps in patients with untreated anterior cruciate ligament injury of the knee joint].

UNLABELLED: In order to study the role of muscle strength in patients with untreated anterior cruciate ligament (ACL) injury of the knee joint, the torque of the quadriceps was isokinetically measured during concentric contraction (CC) and passive eccentric contraction (PEC). The results were compared with those in normal individuals and sports players. Ninety patients with untreated ACL injury were subjected for the study. There were 50 men and 40 women. The normal group consisted of 20 students and the sports player group consisted of 20 soccer players. The peak torque and the torque at 30 degrees flexion of the quadriceps were isokinetically measured during CC and PEC by using a BIODEX machine. RESULTS: In patients with ACL injury, the peak torque was smaller in the injured side as compared with the uninjured side. At the same angle velocity, decrease of PEC in the injured side was larger than that of CC. These results were compared with the normal group and the sports player group. There was significant difference in the peak torque per body weight among each groups. But, the torque per body weight at 30 degrees flexion was almost consistent in these three groups. DISCUSSION: A considerable quadriceps atrophy occurs following ACL injury. In our experience, patients with functional absence of ACL are much more difficult to return to vigorous sports which require explosive eccentric contraction than to return to endurance sports which require repetitive concentric contractile efforts of the quadriceps. In the present study, decrease of the passive eccentric contraction in the injured side was more pronounced than that of the concentric contraction. From these results, the significantly decreased passive eccentric torque in the patients with untreated ACL injury can be a factor to cause instability of the knee joint in active daily life as well as in sports activities.

Adolescent↗
PubMed1993

Immunoreactivities of Reed-Sternberg cells and their variants in the sequential biopsy of Hodgkin's disease.

Reactivities of Reed-Sternberg (RS) cells for antibodies against T-lymphocytes and B-lymphocytes together with CD30 and CD15 were examined in the sequential biopsies of Hodgkin's disease (HD). For this purpose, six patients with lymphocyte predominant (LP) HD, each three of nodular and diffuse types, and three with mixed cellularity (MC) HD were examined. Numbers of times of biopsy in these cases were 25, the intervals between each biopsy ranged from 1 to 92 (median 12) mo. Positive reactivities of the RS cells for CD20, 45R, w75, w74, and/or MB1 were observed in all but one with nodular LPHD. Five of six cass with LPHD showed positive reaction for CD30 and/or CD15. RS cells in all of the present MCHD cases showed a positive reaction for CD30 with each one case showing positive reaction for CD15, CD20, and w75. RS cells in two of three cases with MCHD showed a positive reaction for CD20 or w75. RS cells did not show positive reaction for any antibodies against T-lymphocytes. Sequential biopsy revealed that two of three cases with nodular LPHD and one of three with diffuse LPHD changed to MCHD and two of three with MCHD changed to LDHD. Reactivity of RS cells for CD30 was consistent even when the histologic subtypes changed. Expression of CD15 by RS cells was labile; appearance of disappearance of this antigen during sequential biopsy was frequent. Positive reactivities of RS cells for anti-B-lymphocytes antibodies in LPHD cases disappeared in two cases when histology changed to MCHD. In one case with MCHD, the RS cells became reactive for anti-B-lymphocytes antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Role of total body irradiation as based on the comparison of preparation regimens for allogeneic bone marrow transplantation for acute leukemia in first complete remission.

The role of total body irradiation (TBI) for allogeneic bone marrow transplantation (BMT) for acute leukemia in first complete remission was reevaluated in this study. From Japanese BMT Registry, data of 123 acute leukemia patients in first complete remission who underwent allogeneic bone marrow transplantation in 22 hospitals between 1988 and 1990 were available for the present comparative study of preparation regimens with or without total body irradiation. Two-year survivals were 77% and 51% in the TBI containing regimen group and in the non-TBI regimen group, respectively (p = 0.0010). Corresponding two-year relapse rates were 16% and 37%, respectively (p = 0.0197). Corresponding probabilities of developing interstitial pneumonitis were 21% and 24%, respectively (p = 0.8127). The analysis of causes of death indicated that non-TBI regimen increased the incidence of septicemia and lethal organ failures, such as liver, heart, lung and other multiple sites. It was emphasized that an additional role of total body irradiation was to disperse the treatment-related toxicity in allogeneic bone marrow transplantation for acute leukemia.

Acute Disease↗
PubMed1992

Purification and characterization of DNA topoisomerase IV in Escherichia coli.

The subunits of topoisomerase IV (topo IV), the ParC and ParE proteins in Escherichia coli, were purified to near homogeneity from the respective overproducers. They revealed type II topoisomerase activity only when they were combined with each other. In the presence of Mg2+ and ATP, topo IV was capable of relaxing a negatively or positively supercoiled plasmid DNA or converting the knotted P4 phage DNA, whether nicked or ligated, to a simple ring. However, supercoiling activity was not detected. The topoisomerase activity was not detectable when the purified ParC and ParE proteins were combined with the purified GyrB and GyrA proteins, respectively. This is consistent with the result that neither a parC nor a parE mutation was compensated by transformation with a plasmid carrying either the gyrA or the gyrB gene. Simultaneous introduction of both the gyrA and gyrB plasmids corrected the phenotypic defect of parC and parE mutants. The results suggest that DNA gyrase can substitute for topo IV at least in some part of the function for chromosome partitioning. Antisera were prepared against the purified ParC, ParE, GyrA, and GyrB proteins and used to investigate cellular localization of these gene products. ParC protein was found to be specifically associated with inner membranes only in the presence of DNA. This result suggests that one of the functions of topo IV might be to anchor chromosomes on membranes as previously proposed for eukaryotic topoisomerase II.

Bacterial Proteins↗
PubMed1992

Prognostic factor of telecobalt therapy for early glottic carcinoma.

BACKGROUND: Local control rates of T1 and T2 glottic carcinoma treated with radiation alone were reported as 80-91% and 63-76%, respectively. The authors investigated the factors that affect the local control rate for early glottic carcinoma. METHODS: From 1967 through 1982, 330 patients with early glottic carcinoma (T1: 274 patients; T2: 56) were treated with telecobalt therapy at the Department of Radiology, Osaka University Hospital, Osaka, Japan. RESULTS: Five-year actuarial survival rates of patients with T1 and T2 were 79% and 80%, respectively. Five-year local disease control rates of patients with T1 and T2 disease were 81% and 67%, respectively. In 243 of 254 patients treated with 2 Gy a day, tumor response could be evaluated at the dose level of 40 Gy. For tumors treated with a daily dose of 2 Gy, local control rates of 153 tumors that disappeared at 40 Gy and 90 tumors that persisted at 40 Gy were 83% and 62%, respectively (P < 0.001). Field size and daily fraction size did not affect the local control rate. CONCLUSION: Evaluation of tumor response at 40 Gy was an important indicator of local disease control for early glottic cancers treated with 2 Gy a day.

Cobalt Radioisotopes↗
PubMed1992

Characterization of cDNA encoding the mouse DNA topoisomerase II that can complement the budding yeast top2 mutation.

Several cDNA clones encoding mouse DNA topoisomerase II were obtained from a mouse spermatocyte cDNA library and the entire coding sequence of the gene was determined. The mouse DNA topoisomerase II consists of 1528 amino acids with a molecular weight of 173 kDa. It shares significant homologies with the other eucaryotic enzymes, although species-specific sequences are observed in their highly charged C-terminal regions. The complete mouse TOP2 cDNA was put under yeast GAL1 promoter and examined for complementation of top2ts mutation in S.cerevisiae. We found that the cloned mouse gene could rescue the temperature-sensitive top2ts mutation, depending on its induction by galactose. The functional expression of the mouse DNA topoisomerase II in yeast was further confirmed by enzymatic assays and by immunological methods with antibodies specific for the mouse enzyme.

Amino Acid Sequence↗
PubMed1992

In vitro proliferation and the cytotoxic specificity of a cryopreserved cytotoxic T cell clone reacting against human autologous tumor cells.

Proliferation and functional maintenance of CTL after cell cryopreservation often proves to be quite difficult. We developed an improved method for proliferating cryopreserved CTL, and for gaining their specific cytotoxic function. T cells were cryopreserved at -180 degrees C in RPMI 1640 containing 50% FCS and 10% DMSO. The cryopreserved T cells were well recovered by culturing in a medium containing the supernatant of primary cultures with TIL and autologous tumor cells, in addition to a high concentration (350 U/ml) of rIL-2. Furthermore, these cells were proliferated more efficiently when MMC-treated autologous tumor cells were used in vitro as a feeder and an antigenic stimulant. However, such a high dose IL-2 cultivation resulted in the loss of cytotoxic reactivity of CTL clone. In contrast, the withdrawal of rIL-2 from in vitro cultivation for 24 h prior to the cytotoxic assays conferred the specificity of cytotoxicity on CTL. By these methods, one can obtain a large number of CTL, and pursue the physiologic detail of the specific cytotoxic mechanism of CTL against autologous human tumor cells.

Antigens, Surface↗
PubMed1992

A rat model of human T lymphocyte virus type I (HTLV-I) infection. 1. Humoral antibody response, provirus integration, and HTLV-I-associated myelopathy/tropical spastic paraparesis-like myelopathy in seronegative HTLV-I carrier rats.

Human T lymphocyte virus type I (HTLV-I) can be transmitted into several inbred strains of newborn and adult rats by inoculating newly established HTLV-I-immortalized rat T cell lines or the human T cell line MT-2. The transmission efficiency exceeds 80%, regardless of strain differences or the age at transmission. The production of anti-HTLV-I antibodies significantly differs among the strains and depends on the age at the time of transmission. Rats neonatally inoculated with HTLV-I-positive rat or human cells generally become seronegative HTLV-I carriers throughout their lives, whereas adult rats inoculated with HTLV-I-positive cells at 16 wk of age become seropositive HTLV-I carriers. The HTLV-I provirus genome is present in almost all organs, regardless of whether the carriers are seronegative or seropositive. According to antibody titers to HTLV-I, there are three groups of inbred rat strains: ACI, F344, and SDJ (high responders); WKA, BUF, and LEJ (intermediate responders); and LEW (low responder). Three of three 16-mo-old seronegative HTLV-I carrier rats of the WKA strain developed spastic paraparesis of the hind legs. Neuropathological examinations revealed that the lesions were confined primarily to the lateral and anterior funiculi of the spinal cord. Both myelin and axons were extensively damaged in a symmetrical fashion, and infiltration with massive foamy macrophages was evident. The most severe lesions were at levels of the thoracic cord and continued from the cervical to the lumbar area. These histopathological features as well as clinical symptoms largely parallel findings in humans with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). These HTLV-I carrier rats, in particular the WKA rats described above, can serve as a useful animal model for investigating virus-host interactions in the etiopathogenesis of HTLV-I-related immunological diseases, particularly HAM/TSP.

Aging↗
PubMed1992

Cloning and sequencing of the aculeacin A acylase-encoding gene from Actinoplanes utahensis and expression in Streptomyces lividans.

Aculeacin A acylase (AAC), produced by Actinoplanes utahensis, catalyzes the hydrolysis of the palmitoyl moiety of the antifungal antibiotic, aculeacin A. Using mixed oligodeoxyribonucleotide probes based on the N-terminal amino acid (aa) sequences of the two subunits of AAC, overlapping clones were identified in a cosmid library of A. utahensis DNA. After the sub-cloning of a 3.0-kb fragment into Streptomyces lividans, the recombinant produced AAC extracellularly. The nucleotide sequence of this fragment predicted an open reading frame of 2358 bp with GTG start and TGA stop codons. The deduced 786-aa sequence should correspond to a single polypeptide chain, indicating that this polypeptide is processed to the active form which is composed of the two subunits. Threefold more AAC was obtained from the S. lividans recombinant carrying the cloned gene than the original A. utahensis strain.

Actinomycetales↗
PubMed1992

Low c-kit expression of cultured mast cells of mi/mi genotype may be involved in their defective responses to fibroblasts that express the ligand for c-kit.

Mutant mice of mi/mi genotype are osteopetrotic and deficient in tissue mast cells due to a defect in osteoclasts and mast cells. In an effort to further understand the mechanisms behind why mi/mi mouse-derived cultured mast cells (mi/mi-CMC) responded to interleukin-3 (IL-3), but not to the proliferative stimuli presented by fibroblasts, mi/mi-CMC and congenic normal (+/+) mouse-derived CMC (+/+-CMC), both of which expressed the phenotypic characteristics of immature mast cells, were cocultured with Swiss albino/3T3 fibroblasts in a medium containing IL-3. In the in vitro CMC/fibroblast coculture, mi/mi-CMC did not acquire the phenotypes of connective tissue-type mast cells (CTMC), while +/+-CMC did. In addition, attachment of mi/mi-CMC to the fibroblasts was found to be significantly lower than that of +/+-CMC. Because the interaction of c-kit product with its ligand (stem cell factor [SCF]) is known to play an important role not only in proliferation and differentiation of mast cells but also in attachment of CMC to fibroblasts, the expression and function of c-kit were investigated in mi/mi-CMC and +/+-CMC. Recombinant rat SCF (rrSCF164) induced a dose-dependent proliferation of +/+-CMC. Also, rrSCF164 induced +/+-CMC to acquire the phenotypes of CTMC in the medium containing IL-3. By contrast, rrSCF164 did not stimulate the proliferation of mi/mi-CMC nor induce a phenotypic change of the cells from immature mast cells to mature, CTMC-like mast cells. Immunoblotting with antiphosphotyrosine antibody showed that rrSCF164 induced considerable tyrosine phosphorylation of 145- to 165-Kd protein, the product of c-kit, in +/+-CMC, whereas tyrosine phosphorylation of the protein was barely detectable in mi/mi-CMC. Northern blot and flow cytometry analyses showed that mi/mi-CMC expressed much less c-kit at both protein and message levels than +/+-CMC. Further, mi/mi-CMC were found to differ from +/+-CMC in the expression of mouse mast cell protease-6 (MMCP-6) and MMCP-2 messenger RNA transcripts. These results suggest that the gene product of the mi locus may be important in regulating the expression of gene products such as c-kit, and that mast cell deficiency of mi/mi mice appears to be due, at least in part, to impaired signaling through the c-kit receptor because of the low c-kit expression.

3T3 Cells↗
PubMed1992

Bioluminescence detection system of mutagen using firefly luciferase genes introduced in Escherichia coli lysogenic strain.

A rapid and convenient microbial sensing system for mutagens was developed based upon the induction of prophage from Escherichia coli lysogenic strain and bioluminescence. The system consisted of lysogenic E. coli encoding firefly luciferase genes and a photodetection system. Measurement of mutagen mitomycin C was achieved by measuring the luminescence intensity emitted from E. coli lysogenic strain for the recombinant phage in the presence of luminescence substrates. Approximately 1 h after addition of mitomycin C, the luminescence began to be observed, and 3 h after, it attained a level of 2 times greater than that of 1 h. Irradiation with ultraviolet light also produced light based on induction of phage from the E. coli lysogenic strain for the recombinant phage. On the other hand, when nonmutagenic toxic compounds like sodium azide were added to the reaction medium, luminescence was not observed. Mitomycin C could be detected within 1 h with this sensing system, at concentrations down to 10(2) ng/assay.

Bacteriophage lambda↗
PubMed1992

Studies on antidiabetic agents. 11. Novel thiazolidinedione derivatives as potent hypoglycemic and hypolipidemic agents.

In the course of further chemical modification of the novel antidiabetic pioglitazone (AD-4833, U-72,107), a series of 5-[4-(2- or 4-azolylalkoxy)benzyl- or -benzylidene]-2,4-thiazolidinediones was prepared and evaluated for hypoglycemic and hypolipidemic activities in insulin-resistant, genetically obese, and diabetic KKA(y) mice. Replacement of the 2-pyridyl moiety of pioglitazone by a 2- or 4-oxazolyl or a 2- or 4-thiazolyl moiety greatly enhanced in vivo potency. The corresponding 5-benzylidene-type compounds, in which a methine was used as a linker between the benzene ring and the thiazolidinedione ring, also had potent biological activity. Among the compounds synthesized, 5-[4-[2-(5-methyl-2-phenyl-4-oxazolyl)ethoxy]benzyl]-2,4- thiazolidinedione (18) exhibited the most potent activity, more than 100 times that of pioglitazone. The synthesis and structure-activity relationships for this novel series of derivatives are detailed.

Animals↗
PubMed1992

Diversity of immunodominant 56-kDa type-specific antigen (TSA) of Rickettsia tsutsugamushi. Sequence and comparative analyses of the genes encoding TSA homologues from four antigenic variants.

There are several antigenic variants in Rickettsia tsutsugamushi, and a type-specific antigen (TSA) of 56-kilodaltons located on the rickettsial surface is responsible for the variation. The primary structures of the protein in two variants, Gilliam and Karp, have been reported independently by us and Stover et al. by cloning and sequencing the corresponding genes (Ohashi, N., Nashimoto, H., Ikeda, H., and Tamura, A. (1990) Gene (Amst.) 91, 119-122; Stover, C. K., Marana, D. P., Carter, J. M., Roe, B. A., Mardis, E., and Oaks, E. V. (1990) Infect. Immun. 58, 2076-2084). In the present study, genes encoding the TSA homologues of the other four variants, Kato, Kawasaki, Kuroki, and Shimokoshi, which are all distinguishable serologically, were cloned and sequenced, and consequently, it became possible to compare the primary structures of the six antigenic variants. The sequence analyses revealed a complete open reading frame encoding 55,308-56,745-dalton proteins with 521-532 amino acids, in which a putative signal peptide consisting of 22 amino acids was recognized at the NH2-terminal end. Transcription of the gene is regulated by several tandem promoters. All TSA molecules have the characteristics of transmembrane proteins with alternating hydrophobic and hydrophilic regions, and contain four variable domains with spans of 16-40 amino acids which are located in the hydrophilic regions in the molecule and show different amino acid sequences among the strains. Phylogenetic classification among the R. tsutsugamushi strains based on TSA homologues supports the antigenic relationships known in the closely and distantly related strains.

Amino Acid Sequence↗
PubMed1992

[Endobronchial intraluminal brachytherapy for patients with tracheobronchial carcinoma with high dose-rate 192-Iridium remote afterloading method].

Endobronchial intraluminal brachytherapy was conducted for 5 patients with tracheobronchial carcinoma using 192Iridium high dose-rate afterloading machine (microSelectron HDR) and guide tubes of 1.9 mm in outer diameter. Four patients with bronchial non-small cell carcinoma and one with tracheal adenocarcinoma were applied, and a dose of 6 Gy/Fr. at points 1 cm from the source once a week, and a cumulative dose of 18 Gy/3 Fr. was delivered. Guide tubes could be placed up to 3 tubes via the vocal airway, and new computer planning system could afford to calculate dose from independent lining of the source into optimization. This could be done with safety, and no remarkable acute side effects were observed attributable to this method.

Brachytherapy↗
PubMed1992

Vasoactive intestinal polypeptide presynaptically enhances the synaptic transmission in cultured sympathetic neurons.

We studied the effects of vasoactive intestinal polypeptide (VIP) on the cholinergic synaptic transmission that was developed between rat sympathetic neurons in culture. Electrophysiological examinations revealed that the amplitude of fast excitatory postsynaptic potential (fast EPSP) was increased by VIP (0.2-0.8 microM) reversibly and dose-dependently, whereas transient nicotinic depolarization evoked by pressure application of acetylcholine (ACh) was not affected by VIP. In most of the cells examined, VIP depolarized membrane potential by a few millivolts with concomitant increases in membrane conductance. Furthermore, the VIP-induced depolarization was suppressed by Co2+ but not by hexamethonium or atropine. Hence it is highly likely that the peptide augmented the amplitude of fast EPSPs by increasing ACh release from the presynaptic cell. These results demonstrate that VIP influences the presynaptic phase of cholinergic synaptic transmission between sympathetic neurons.

Acetylcholine↗