Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 235 records · Page 13Linked to original sources

PubMed1996

Interleukin-1 alpha activates an NF-kappaB-like factor in osteoclast-like cells.

We investigated the NF-kappaB transcription factor in osteoclast-like cells. Osteoclast-like cells were differentiated from mouse bone marrow cells in co-culture with mouse calvaria-derived primary osteoblasts in the presence of 1alpha,25-dihydroxyvitamin D3 and prostaglandin E2 in collagen gel-coated dishes. We enriched osteoclast-like cells from the co-cultures by Pronase treatment. When the enriched osteoclast-like cells were treated with phorbol 12-myristate 13-acetate, interleukin-1 (IL-1), calcitonin, or macrophage colony-stimulating factor, only IL-1 activated an NF-kappaB-like factor, which specifically bound to a kappaB motif DNA sequence, as detected by an electrophoretic mobility shift assay. IL-1 also activated NF-kappaB induction in osteoblasts. However, the NF-kappaB-like factor induced by IL-1-stimulated osteoclast-like cells is of smaller molecular size than the factor in osteoblasts, as shown by an electrophoretic mobility shift assay. The NF-kappaB activity of osteoclast-like cells was recognized completely by antibodies against the p50 subunit, and only partially by antibodies against the p65 subunit of NF-++kappaB. Antibodies against c-Rel, Rel B, and p52 did not recognize the NF-kappaB-like factor. These results suggest that IL-1 activates an NF-kappaB-like factor in osteoclast-like cells, which contains p50 and p65-related proteins.

Animals↗

PubMed1996

Targeted disruption of gp130, a common signal transducer for the interleukin 6 family of cytokines, leads to myocardial and hematological disorders.

gp130 is a ubiquitously expressed signal-transducing receptor component shared by interleukin 6, interleukin 11, leukemia inhibitory factor, oncostatin M, ciliary neurotrophic factor, and cardiotrophin 1. To investigate physiological roles of gp130 and to examine pathological consequences of a lack of gp130, mice deficient for gp130 have been prepared. Embryos homozygous for the gp130 mutation progressively die between 12.5 days postcoitum and term. On 16.5 days postcoitum and later, they show hypoplastic ventricular myocardium without septal and trabecular defect. The subcellular ultrastructures in gp130-/- cardiomyocytes appear normal. The mutant embryos have greatly reduced numbers of pluripotential and committed hematopoietic progenitors in the liver and differentiated lineages such as T cells in the thymus. Some gp130-/- embryos show anemia due to impaired development of erythroid lineage cells. These results indicate that gp130 plays a crucial role in myocardial development and hematopoiesis during embryogenesis.

Animals↗

PubMed1996

A new inositol 1,4,5-trisphosphate binding protein similar to phospholipase C-delta 1.

We have reported that two inositol 1,4,5-trisphosphate binding proteins, with molecular masses of 85 and 130 kDa, were purified from rat brain; the former protein was found to be the delta 1-isoenzyme of phospholipase C (PLC-delta 1) and the latter was an unidentified novel protein [Kanematsu, Takeya, Watanabe, Ozaki, Yoshida, Koga, Iwanaga and Hirata (1992) J. Biol. Chem. 267, 6518-6525]. Here we describe the isolation of the full-length cDNA for the 130 kDa Ins(1,4,5)P3 binding protein, which encodes 1096 amino acids. The predicted sequence of the 130 kDa protein had 38.2% homology to that of PLC-delta 1. Three known domains of PLC-delta 1 (pleckstrin homology and putative catalytic X and Y domains) were located at residues 110-222, 377-544 and 585-804 with 35.2%, 48.2% and 45.8% homologies respectively. However, the protein showed no PLC activity to phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol. The 130 kDa protein expressed by transfection in COS-1 cells bound Ins(1,4,5)P3 in the same way as the molecule purified from brain. Thus the 130 kDa protein is a novel Ins(1,4,5)P3 binding protein homologous to PLC-delta 1, but with no catalytic activity. The functional significance of the 130 kDa protein is discussed.

Amino Acid Sequence↗

PubMed1996

Digital sensory nerve conduction velocity and vibration perception threshold in peripheral neurological test for hand-arm vibration syndrome.

To evaluate peripheral neuropathy in patients with vibration syndrome, an examination was conducted of sensory nerve conduction velocity (SCV) in the digital segment of the median nerve in the middle finger and vibration perception threshold (VPT) at 125 Hz on the same middle fingertip. In addition, possible correlations were investigated between the two measurements. SCVs in the digital segment were measured by stimulating at the wrist electrically and recording from two pairs of electrodes in the finger. Fractionated SCVs were also measured in the palm-to-finger, wrist-to-palm, and elbow-to-wrist segments. The subjects were 52 patients with vibration syndrome and 40 healthy controls of similar age. SCVs in the digital segment and the wrist-to-palm segment were significantly slower in the patients than in the controls, and VPTs were higher in the patients. The strongest correlation of VPTs with SCVs among nerve segments measured was shown in the digital segment. With an increase in VPTs, SCVs in the digital segment tended to be slower, and slowed digital SCVs were encountered more frequently: 13% in VPTs below 5.0 dB and 56% in VPTs above 17.5 dB. Slowed digital SCVs were found in 43% of the patients and increased VPTs were encountered in 92%.

Arm↗

PubMed1996

Basic fibroblast growth factor inhibits osteoclast-like cell formation.

Basic fibroblast growth factor (bFGF) inhibited osteoclast-like cell formation in co-cultures of mouse bone marrow cells either with the mouse stromal cell line, ST2, or with primary osteoblastic cells. Basic FGF significantly inhibited the osteoclast-like cell formation, induced by 1 alpha,25-dihydroxyvitamin D3[1 alpha, 25(OH)2D3] when the cytokine was added to the culture, at an intermediate stage, suggesting that bFGF inhibits the differentiation of the osteoclast progenitors. With regard to target cells, bFGF directly affected ST2; it increased [3H] thymidine uptake and decreased the number of alkaline phosphatase-positive cells. In contrast, bFGF had no inhibitory effect on the colony formation of bone marrow cells induced by macrophage colony stimulating factor in methylcellulose culture. In addition, ST2 cells treated with bFGF produced similar amounts of colony forming activity to those without the cytokine. These findings indicated that the bFGF is not involved in the proliferation of progenitor cells even in the presence of ST2 cells. Furthermore, bFGF inhibited osteoclast-like cell formation induced not only by 1 alpha,25(OH)2D3, but also by prostaglandin E2 and by interleukin-11. These results suggest that bFGF inhibits the common site of osteoclast-like cell formation, as induced by different mechanisms. Our data also indicated that the target cells for bFGF in inhibiting osteoclast formation are not osteoclast progenitors but stromal cells such as ST2 and osteoblastic cells, which support osteoclast development.

Acid Phosphatase↗

PubMed1996

Testicular toxicity of gallium arsenide, indium arsenide, and arsenic oxide in rats by repetitive intratracheal instillation.

The testicular toxicities of two compound semiconductor materials, gallium arsenide (GaAs) and indium arsenide (InAs), and arsenic oxide (As2O3) were examined in rats by repetitive intratracheal instillation of these substances in suspension twice a week, a total of 16 times. A single instillation dose was 7.7 mg/kg in the GaAs and the InAs groups and 1.3 mg/kg in the As2O3 group. A significant decrease in sperm count and significant increase in the proportion of morphologically abnormal sperm were found in the epididymis in the GaAs group. Especially, abnormal sperm with a straight head increased markedly in this group. In the GaAs-treated rats, there was 40-fold increase in the degenerating late elongated spermatids at the postspermiation stages, stages IX, XI, and XI. From these results, it is indicated that GaAs disturbed the spermatid head transformation at the late spermiogenic phases and caused spermiation failure. InAs caused a sperm count decrease in the epididymis, though its testicular toxicity was relatively weak compared with that of GaAs. As2O3, a probable dissolution arsenic product of GaAs and InAs in vivo, did not show any testicular toxicities in this study. It seems likely that, along with arsenics, gallium and indium play a role in the testicular toxicities of GaAs and InAs.

Animals↗

PubMed1996

Lipopolysaccharides from Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans promote osteoclastic differentiation in vitro.

Bacterial lipopolysaccharides possess bone-resorbing activity. Here, lipopolysaccharides from three putative periodontopathic bacteria were examined for effects on osteoclast-like cell formation of bone marrow cells from lipopolysaccharide-responsive C3H-HeN and non-responsive C3H/HeJ mice. The bone marrow cells were cultured with or without various doses of lipopolysaccharide in the presence of 1,25-dihydroxyvitamin D3 and dexamethasone. These lipopolysaccharide preparations significantly increased the number of osteoclast-like cells formed in the culture of C3H/HeN marrow cells; the same as lipopolysaccharides from Escherichia coli and a synthetic lipid A with E. coli-type structure (LA-15-PP), at doses from 0.1 to 1 microgram/ml. This stimulating effect of each lipopolysaccharides was uniformly abrogated by the addition of polymyxin B at 5 micrograms/ml. All the lipopolysaccharide and the synthetic lipid A had no effect on osteoclast formation of the C3H/HeJ marrow cells, whereas lipopolysaccharide from Porphyromonas gingivalis and Prevotella intermedia showed significant mitogenic activity on C3H/HeJ spleen cells. It seems likely that the activity of lipopolysaccharides to augment osteoclast-like cell formation in the bone marrow cell cultures is derived from a common structure of the lipid A portion.

Acid Phosphatase↗

PubMed1996

Characteristics of pancreatic injury in children: a comparison with such injury in adults.

A retrospective study of eight pediatric patients (under 15 years of age) who had pancreatic injuries was undertaken. Comparisons were made with 59 adult patients who sustained pancreatic injuries over the same 15-year period. All the pediatric injuries and 96.6% of the adult resulted from blunt abdominal trauma. Bicycle accidents (children, 75.0%; adults, 0%; P < .001) and automobile accidents (children, 0%; adults, 61.0%; P < .01) were the most common causes of pancreatic injury in the two groups. There was no significant difference in the incidence of abdominal pain or peritoneal irritation between the groups. However, abdominal pain in the adults was poorly localized. Isolated pancreatic injuries were noted in 62.5% of the pediatric patients and in 15.3% of the adult patients (P < .05). Associated intraabdominal injuries were present in 25.0% of the children and in 69.5% of the adults (P < .05). The duodenum was injured in two (25.0%) pediatric patients and in 10 (16.9%) adult patients. Whereas the duodenal injuries in pediatric patients were intramural hematomas without perforation in both cases, all but one of these injuries in adults were perforations or transections (P < .05). There was a significant difference in the type of pancreatic injury between the two groups (P < .05). Surgery was performed in 12.5% of the pediatric cases and in 78.0% of the adult cases (P < .01). There were no deaths among the pediatric patients, but 8.5% of the adults died in the hospital. The difference with respect to clinical course might be related to the differences in cause of injury.

Abdominal Injuries↗

PubMed1996

A cysteine protease inhibitor stored in the large granules of horseshoe crab hemocytes: purification, characterization, cDNA cloning and tissue localization.

A cysteine protease inhibitor with an apparent Mr = 12,600, designated limulus (L)-cystatin, was isolated from hemocyte lysates of the Japanese horseshoe crab (Tachypleus tridentatus), using two steps of chromatography, including dextran sulfate-agarose, and carboxymethylated papain-agarose. L-cystatin inhibits amidolytic activity of papain by forming a noncovalent 1:1 complex with an equilibrium constant (Ki) of 0.08 nM. It also inhibits cathepsin L (Ki = 0.17 nM) and ficin (Ki = 0.52 nM), but not argingipain (a bacterial cysteine protease) and calpains. A cDNA for L-cystatin was isolated and the open reading frame coded for a mature protein of 114 amino acids, of which 99 residues were confirmed by peptide sequencing. L-cystatin shows significant sequence identities to members of the family 2 cystatin, such as bovine colostrum cystatin (33%) and human cystatin S (31%). Northern blotting revealed expression of the mRNA in hemocytes and slightly in heart but expression was negligible in hepatopancreas, intestine, stomach, and muscle. Immunoblotting revealed the localization to be in the large granules of hemocytes. Furthermore, L-cystatin has an antimicrobial activity against Gram-negative bacteria, which is much stronger than that of chicken egg white cystatin. These data suggest that the large granule-derived L-cystatin serves synergistically to accomplish an effective defense against invading microbes, together with other defense molecules that are released in response to external stimuli.

Agglutinins↗

PubMed1996

Tachycitin, a small granular component in horseshoe crab hemocytes, is an antimicrobial protein with chitin-binding activity.

Small granules of horseshoe crab hemocytes contain two known major antimicrobial substances, tachyplesin and big defensin (S5), and at least five protein components (S1 to S6), with unknown functions. In the present study, we examined the biological properties and primary structure of a small granular component S2, named tachycitin. This component was purified from the acid extract of hemocyte debris by two steps of chromatography. The purified tachycitin was a single chain protein with an apparent M(r) = 8,500 on Tricine-SDS-polyacrylamide gel electrophoresis. Ultracentrifugation analysis revealed tachycitin to be present in monomer form in solution. Tachycitin inhibited the growth of both Gram-negative and -positive bacteria, and fungi, with a bacterial agglutinating property. Moreover, tachycitin and big defensin acted synergistically in antimicrobial activities. The amino acid sequence and intrachain disulfide bonds of tachycitin were determined by amino acid and sequence analyses of peptides produced by enzymatic cleavages. The mature tachycitin consisted of 73 amino acid residues containing five disulfide bonds with no N-linked sugar. A cDNA coding for tachycitin was isolated from a hemocyte cDNA library. The open reading frame coded for an NH2-terminal signal sequence followed by the mature peptide and an extension sequence of -Gly-Arg-Lys at the COOH-terminus, which is a putative amidating signal. The COOH-terminal threonine amide released after digestion of tachycitin with lysylendopeptidase was identified. The NH2-terminal 28 residues of tachycitin shows sequence homology to a part of chitin-binding regions found in antifungal chitin-binding peptides, chitin-binding lectins, and chitinases, all of which have been isolated from plants. Tachycitin showed a specific binding to chitin but did not bind with the polysaccharides cellulose, mannan, xylan, and laminarin. Tachycitin may represent a new class of chitin-binding protein family in animals.

Amino Acid Sequence↗

PubMed1996

Role of repeat computed tomography after emergency endoscopic retrograde pancreatography in the diagnosis of traumatic injury to pancreatic ducts.

Endoscopic retrograde pancreatography (ERP) is performed on patients with pancreatic injury after abdominal trauma. To delineate pancreatic ductal injuries more accurately, we performed repeat computed tomography (CT) shortly after completion of ERP. We describe our experiences with six patients to demonstrate the feasibility and utility of this method. In our cases, the diagnosis of pancreatic ductal injury was made with certainty on the basis of the presence of extravasated contrast medium. This protocol is useful for reaffirmation of injuries noted on ERP, for diagnosis of injuries not noted on ERP, and for exclusion of injuries in patients with equivocal results of ERP. Moreover, the protocol is easy to implement because it involves only the transfer of the patient from the endoscopy to the CT suite. The technique can be used to clarify potentially confusing situations.

Abdominal Injuries↗

PubMed1996

In vivo and in vitro cellular response to Schistosoma japonicum eggs in hosts with differing susceptibilities.

A comparative study of the cellular response to Schistosoma japonicum eggs was conducted in order to explore its significance, using hosts with differing susceptibilities to the parasite. In experimentally induced, synchronized hepatic granuloma formation, animal species formed each characteristic feature of the granulomas, and the magnitude of tissue reaction was significantly larger in highly susceptible hosts, such as mice and hamsters, while less susceptible hosts, such as rats and quails, formed smaller granulomas. Confluent neutrophils were seen within the tissue lesions for mice and hamsters, while rats and quails showed obviously scanty neutrophils. Guinea pigs failed to develop any granulomas. When splenic cells and bone marrow cells were used for in vitro granuloma formation, bone marrow cells showed markedly higher reactions than splenic cells from naive or sensitized animals and the reactivities of bone marrow cells from susceptible hosts, mice and hamsters, were clearly higher than those from rats, indicating similar results to those of in vivo granuloma formation. This study indicates that the in vivo and in vitro cellular response to S. japonicum eggs varies greatly according to the host's susceptibility, independent of whether the host is a naive or sensitized animal. Our results seem to support the concept that the parasites exploit the host immune system in order to complete their life-span.

Animals↗

PubMed1996

Vitamin D receptor in endometrial carcinoma and the differentiation-inducing effect of 1,25-dihydroxyvitamin D3 on endometrial carcinoma cell lines.

In view of the potential of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] as a cell-differentiation-inducing agent in endometrial cancer, the localization of the vitamin D receptor (VDR) was examined immunohistochemically in 21 endometrial adenocarcinoma specimens, and the effect of 1,25(OH)2D3 on cell growth, as well as the phenotypic changes for cell maturation after treatment with 1,25(OH)2D3, was investigated in 2 endometrial carcinoma cell lines (AMEC-1, RL95-2). The VDR was detected in 14 of the 21 endometrial carcinoma specimens. The growth of RL95-2 cells expressing VDR was inhibited to 44% when cultured with 50 nM 1,25(OH)2D3 for 6 days. In contrast, the growth of AMEC-1 cells not expressing VDR was completely uninhibited even when cultured with 100 nM 1,25(OH)2D3 for 6 days. The RL95-2 cells exposed to 50 nM 1,25(OH)2D3 for 6 days had an increasing expression for 52.5 kD or 45 kD cytokeratin polypeptide, and they became columnar with pronounced polarity and formed gland-like structures when cultured in collagen gel. These results suggest that endometrial adenocarcinoma is a target for 1,25(OH)2D3, which appears to function as a cell-differentiation-inducing agent for the treatment of endometrial cancer.

Adenocarcinoma↗

PubMed1996

The expression of IL-6 and its related genes in acute leukemia.

Acute myeloid leukemia (AML) blast cells frequently produce interleukin-6 (IL-6) and other cytokines such as colony-stimulating factors (CSF: G-CSF, M-CSF, and GM-CSF), tumor necrosis factor (TNF)-alpha, and IL-1. The AML blast cells that produced IL-6 alone could not form autonomous in vitro colonies, whereas the blast cells that coexpressed CSF in addition to IL-6 were able to form such colonies. This suggests that IL-6 acts as a costimulator to enhance CSF-induced clonogenicity of AML blast cells. TNF-alpha and IL-1 that are produced from the blast cells may stimulate the growth of the AML blast cells by inducing production of CSF in bone marrow stromal cells or in the blast cell population itself. Improvement of clinical manifestations by the administration of an anti-IL-6 murine monoclonal antibody in a patient with AML-M5B confirmed an important role of IL-6 in in-vivo growth of the blast cells. The mRNA expression of IL-6 and its related genes in AML and acute lymphoid leukemia (ALL) blast cells was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR). IL-6 mRNA expression was common in AML, but rare in ALL, whereas the IL-6 receptor (IL-6R) mRNA was expressed in almost all cases of AML and in more than half of the cases of ALL. In contrast, gp130 was ubiquitously expressed in both AML and ALL. A significant correlation between the levels of IL-6R expression and the responsiveness of the blast cells to exogenous IL-6 was observed. This suggests the possibility of the rapid prediction of the responsiveness of leukemic cells to exogenous IL-6 (IL-6 administration for therapy) by rapid measurement of IL-6R mRNA by RT-PCR.

Acute Disease↗

PubMed1996

An improved mounting method for observation of thick specimens using confocal microscopy.

When applying aqueous media to mount thick specimens, air bubbles occur frequently between coverslips and slide glasses. This results in an increase of background signal by confocal microscopy. Using Spurr's resin as a mounting medium, we could observe thick specimens with oil immersion objective lens without the use of coverslips, then avoid air bubbles near the specimen. Fading of the fluorescence appeared to be less in specimens mounted by the resin than in specimens mounted by aqueous media. Further, the new method increased depth of field so that more planes of specimens could be analyzed.

Animals↗

PubMed1996

Pathology and cellular kinetics of gallbladder with an anomalous junction of the pancreaticobiliary duct.

OBJECTIVES: Anomalous junction of the pancreaticobiliary duct (AJPBD) is thought to be an important risk factor for gallbladder carcinoma in Japan. In this report, we examine histopathology and cellular kinetics of gallbladder mucosae of patients with AJPBD and the possible risk of gallbladder carcinoma. METHODS: We examined 62 gallbladders from patients with AJPBD (group A), 16 gallbladder carcinomas from patients with AJPBD (group B), 60 gallbladder carcinomas from patients without AJPBD (group C), and six normal gallbladders from patients without AJPBD (group D). Histopathology, mucosal heights, and proliferative cell nuclear antigen-labeling index were obtained from routinely processed tissue specimens. RESULTS: The incidence of hyperplastic changes in group A and in the noncancerous regions (NCRs) of group B was greater than in the NCRs of group C (p < 0.05). The incidence of dysplastic changes in the NCRs of group B was greater than in the NCRs of group C (p < 0.05). The mucosal heights in group A and in the NCRs of group B were higher than in the NCRs of group C (p < 0.05). A high proliferative cell nuclear antigen-labeling index was observed in group A and in the NCRs of group B, where hyperplastic changes were frequently observed. CONCLUSIONS: These results suggest that a sequence of hyperplastic changes with a corresponding increase in cellular kinetics with progression through dysplasia to carcinoma may be important in carcinogenesis in gallbladders of patients with AJPBD. AJPBD itself may be a possible risk for gallbladder carcinoma.

Adolescent↗

PubMed1996

Chronic toxicity of indium arsenide and indium phosphide to the lungs of hamsters.

Chronic toxicity of indium arsenide (InAs) and indium phosphide (InP) was studied in male Syrian golden hamsters which received InAs or InP particles containing a total dose of 7.5 mg of arsenic or phosphorus by intratracheal instillations once a week for 15 weeks. As a control, hamsters were treated with the vehicle, phosphate buffer solution. During their total life span, the cumulative body weight gain of hamsters in the InAs group was suppressed significantly compared with that in the control group, but not in the InP group when compared with that in the control group. Concerning the histopathological findings of the lung, the incidence rates of proteinosis-like lesions, alveolar or bronchiolar cell hyperplasia, pneumonia, emphysema and metaplastic ossification observed in the InAs or InP group were significantly higher than those observed in the control group. From these results, it would seem that InAs and InP produced severe damage to the lungs of hamsters.

Animals↗

PubMed1996

High frequency of p53 gene mutation in adenocarcinomas of the gallbladder.

p53 mutations in adenocarcinomas of the gallbladder were analyzed by deoxynucleotide sequencing of the gene. Of 23 cases, 16 (70%) harbored 18 missense mutations in exon 5, 6, or 8 of the p53 gene. The characteristics of the p53 mutation spectrum observed in gallbladder carcinomas were (a) frequent mutations at an A:T pair [10 (55%) of 18 mutations], (b) high transversion incidence [12 (66%) of 18 mutations], and (c) only one mutation at the CpG site. The immunohistochemical study revealed that 36 (55%) of 65 cases showed an abnormal accumulation of p53 immunoreactivity, and 12 (52%) of 23 cases had p21 expression. No statistical correlation was observed between p53 and p21 immunoreactivity. These results suggest that p53 mutations may confer the carcinogenesis of the adenocarcinoma of the gallbladder with the specific mutation spectrum of p53.

Adenocarcinoma↗