Biomedical subjects

M Enomoto

Publications and source records attributed to M Enomoto.

At least 73 records · Page 4Linked to original sources

PubMed1996

Detection and characterization of the flagellar master operon in the four Shigella subgroups.

Strains in the genus Shigella are nonmotile, but they retain some cryptic flagellar operons whether functional or defective (A.Tominaga, M. A.-H. Mahmoud, T. Mukaihara, and M. Enomoto, Mol. Microbiol. 12:277-285, 1994). To disclose the cause of motility loss in shigellae, the presence or defectiveness of the flhD and flhC genes, composing the master operon whose mutation causes inactivation of the entire flagellar regulon, was examined in the four Shigella subgroups. The flhD operon cloned from Shigella boydii and Shigella sonnei can activate, though insufficiently, the regulon in the Escherichia coli flhD or flhC mutant background. The clone from Shigella dysenteriae has a functional flhD gene and nonfunctional flhC gene, and its inactivation has been caused by the IS1 element inserted in its 5' end. The operon of Shigella flexneri is nonfunctional and has suffered an IS1-insertion mutation at the 5' end of the flhD gene. Comparison of restriction maps indicates that only the central 1.8-kb region, including part of the flhC gene and its adjacent mot operon, is conserved among the four Shigella subgroups as well as in E. coli, but in Salmonella typhimurium the whole map is quite different from the others. Motility loss in shigellae is not attributable to genetic damage in the master operon of a common ancestor, but it occurs separately in respective ancestors of the four subgroups, and in both S. dysenteriae and S.flexneri IS1 insertion in the master operon might be the primary cause of motility loss.

Chromosome Mapping↗

PubMed1996

[A 52-week oral toxicity study of a new antineoplastic agent S-1 in dogs].

52-week oral repeated-dose S-1 toxicity studies were conducted. Male and female dogs were orally treated with 0, 0.1, 0.5 or 2.5 mg/kg/day for 52 weeks and permitted to recover for 13 weeks. Furthermore, to estimate the no-toxic dose, male and female dogs were given S-1 orally for 52 weeks at doses of 0, 0.004 and 0.02 mg/kg/day. The 2.5 mg/kg/day regimen produced one dead or moribund dog of each sex; black-brown patch (melanin deposition) and inflammatory changes in the eyes and skin; decreased in body weight gains; increases in MCV, MCH, monocyte ratio, and serum protein and uric acid; decreases in lymphocyte ratio and erythrocyte count, hematocrit, hemoglobin, albumin, A/G ratio, cholesterol (esterified, total and free), phospholipids, triglycerides, cholinesterase activity and creatinine; increases in relative liver and adrenal weights. Histopathological examinations revealed melanin deposits in superficial lymph nodes, increases in macrophage and plasma cell accumulation, and corneal atrophy accompanied by melanin deposits and capillary proliferation. A slight black-brown patch (melanin deposition) in the conjunctiva and skin was observed in the 0.1 and 0.5 mg/kg/day groups. No drug-related changes were observed in groups that received 0.02 and 0.004 mg/kg/day. All changes observed during the treatment period disappeared during recovery except for melanin deposits in the conjunctiva and superficial lymph nodes, corneal opacity, and a few hematological and blood chemistry parameters. In conclusion, the no-toxic dose in these 52-week studies was estimated to be 0.02 mg/kg/day.

Administration, Oral↗

PubMed1996

[Correlation between periventricular lucency and extracranial arterial lesions].

This study was done to clarify relationships between the degree of periventricular lucency (PVL), and lesions in the carotid arteries and the legs as detected with B-mode ultrasonography and the ankle pressure index, respectively. According to the distribution of PVL on computed tomography, 45 patients were divided into 2 groups: 22 patients with diffuse PVL (from the periventricular white matter to the subcortical area, DPVL group) and 23 patients with PVL localized in the frontal deep white matter (LPVL group). Plaque, defined as a thickened intima-media complex of 2.1 mm or more, was divided into two types; mural plaque and nodular plaque. Hypertension was more common in the DPVL group than in control groups, which consisted of 70 age-matched patients with cerebral thrombosis without PVL (CTH group) and 50 controls with neither PVL nor cerebrovascular lesions (NCT group). All patients in the DPVL group met the diagnostic criteria for Binswanger's disease proposed by Bennett DA. The incidence of low API indices (< 0.9) in the DPVL group (45%) was significantly higher than that in the NCT group, and it was slightly higher than that in the LPVL group. Carotid lesions, mainly nodular plaques, were seen in 82% of patients in the DPVL group and in 74% of those in the LPVL group; these percentages were significantly higher than those in the CTH (49%) and NCT (40%) groups. In particular, bilateral carotid lesions were more common in the DPVL group than in the other three groups. The degree of PVL correlated with lesions in the carotid arteries and the legs. These correlations suggest that the arterial lesions not only resulted from a risk factor (hypertension) for PVL, but also promoted PVL by causing extra- and intra-cranial arterial lesions. Furthermore, they imply that LPVL is a precusor to DPVL.

Aged↗

PubMed1996

Fulminant hepatic failure monitored by technetium-99m-DTPA-galactosyl-human serum albumin scintigraphy.

We describe a 43-yr-old woman with fulminant hepatic failure whose progress was monitored scintigraphically using 99m-Tc-galactosyl-human serum albumin (99mTc-GSA). On admission, the liver was atrophic and the heart was delineated distinctly by scintigraphy with 99m-Tc-GSA. The receptor index, calculated by dividing the radioactivity of the liver region of interest by the radioactivity of the liver plus heart regions of interest at 15 min post-tracer injection, was very low. As the patient's condition improved, the right lobe of the liver enlarged while the left lobe became atrophic; after 4 mo, the left lobe almost completely disappeared. Delineation of the heart gradually became less distinct, and the receptor index slowly increased. Hepatic receptor imaging with 99m-Tc-GSA can define both the hepatic functional reserve and morphological changes of the liver, so it is useful for the diagnosis and follow-up study of fulminant hepatic failure.

Adult↗

PubMed1995

Hepatocyte growth factor promotes the growth of cytotrophoblasts by the paracrine mechanism.

Both placental and decidual tissues contained extractable HGF, the former HGF level (31.4 +/- 23.4 ng/mg total protein) being approximately 30 times the latter HGF level. When the localization of HGF protein and HGF mRNA in placental tissues was examined by immunohistological staining and in situ hybridization, HGF protein and HGF mRNA were detected in the mesenchymal cells of the placenta, but were absent in the cytotrophoblast and syncytiotrophoblast. Although c-met protein was expressed in the cytotrophoblast, this receptor was not detectable in the syncytiotrophoblast by immunohistochemical methods. c-met mRNA was detected in placental cell line (tPA30-1) and 4 choriocarcinoma cell lines (BeWo, Jar, Jeg-3, and NUC-1), but HGF mRNA was absent in these cells. When cytotrophoblast cells were cultured in a serum-free medium in the presence of HGF, their DNA synthesis was enhanced depending on the HGF concentration, although human placental lactogen secretion itself was not affected by HGF. These results demonstrated that HGF promotes the growth of the cytotrophoblast by the paracrine mechanism, although it does not serve as a placental differentiation factor.

Base Sequence↗

PubMed1995

A case of multiple osteochondroma in the rat.

The occurrence of spontaneous osteochondroma in rats is extremely rare and only a few cases have been reported. Spontaneous multiple osteochondroma was found in a male SD strain rat, at the age of 58 weeks from the control group in a toxicity study. Histological findings of both a walnut-sized mass involving the humerus and scapula of right forelimb and a soybean-sized mass adjacent to the costochondrial junction of the right posterior rib were similar in appearance. The outer layer of the tumors consisted of hyaline cartilage and the core of the tumors consisted of trabecular bone with abundant fatty bone marrow. The periosteum of the surface was continuous with that of the parent bone, and cortical bone and the medullary cavity of the parent bone communicated with those of the tumors. Because of showing progressive enlargement, multiple osteochondromas in the rat were considered to be neoplastic in nature.

Animals↗

PubMed1994

Localization of stem cell factor (SCF) and c-kit mRNA in human placental tissue and biological effects of SCF on DNA synthesis in primary cultured cytotrophoblasts.

The supernatant of homogenized human placental tissues at early and late stages of pregnancy were found to contain 40-100 pg of stem cell factor (SCF)/mg of total protein by enzyme linked immunosorbent assay. When the SCF mRNA expression was examined by reverse transcriptase-polymerase chain reaction (RT-PCR), the secretory type and membrane-bound type SCF mRNA were detected in the human placental tissues in the early stages of pregnancy and in a human placental cell line;tPA30-1 cells. However, the secretory type SCF mRNA was predominant and membrane-bound type SCF mRNA was absent or very weak in the term placental tissues. When the distribution of SCF mRNA and c-kit mRNA in the placental tissues was examined by in situ hybridization, SCF mRNA was detected in the cytotrophoblast, the intermediate trophoblastic cell column and the stromal cells, while c-kit mRNA was detected in the cytotrophoblast and the intermediate trophoblastic cell column. Both c-kit and SCF mRNA were absent or very weak in the syncytiotrophoblasts. The supernatant of primary cultured cytotrophoblasts and tPA30-1 cells were found to contain SCF. In cytotrophoblasts in the early stage of pregnancy cultured in the presence of recombinant human secretory type SCF, DNA synthesis was increased depending on the SCF concentration. These findings indicate that SCF is a cytokine which promotes the growth of placental cells by the autocrine and paracrine mechanism.

Base Sequence↗

PubMed1994

Characteristics of somatic mutation of the adenomatous polyposis coli gene in colorectal tumors.

Mutation of the adenomatous polyposis coli (APC) gene was analyzed in 500 colorectal tumors from 70 familial adenomatous polyposis (FAP) and 102 non-FAP patients and in normal tissues from 119 FAP patients, using polymerase chain reaction-single-strand conformation polymorphism and direct sequencing methods. These tumors were histopathologically diagnosed. Sixty-eight germ line mutations (62% deletion, 9% insertion, and 29% single-base substitution) and 241 somatic mutations (56% deletion, 12% insertion, and 32% single-base substitution) were detected. All mutations formed stop codons resulting in truncated APC proteins, except for one germ line mutation. Differences were found between somatic and germ line mutations, including 3 new hot spots of mutation at codons 1378, 1450, and 1487-1490, which frequently occurred in somatic mutations but not in germ lines. The frequency of mutation in each histopathological type of FAP tumor was 53% in moderate adenoma, 64% in severe adenoma, 52% in intramucosal carcinoma, and 33% in invasive carcinoma, whereas the loss of heterozygosity including the APC gene increased with development to each histopathological type. A similar tendency was observed in non-FAP tumors. Additionally, we found 10 FAP tumors that had both somatic mutation and loss of heterozygosity. These tumors were assumed to have developed from moderate adenomas with germ line and somatic mutations, followed by deletion of the allele with germ line mutation. These results suggest that inactivation of the APC gene by two mutations is involved in the development of moderate adenoma, and loss of heterozygosity of the APC gene is associated with further development to carcinoma. It was also observed that the distribution of 75 somatic mutations from one FAP patient on the APC sequence was similar to the distribution of 159 somatic mutations from 83 patients with FAP and non-FAP, which suggests that the position of somatic mutation is mostly due to the APC sequence itself.

Adenoma↗

PubMed1994

Interleukin-8 production by CD16-CD56bright natural killer cells in the human early pregnancy decidua.

Decidual CD16-CD56bright natural killer (NK) cells were sorted from the decidual mononuclear cells (MNC) at the early pregnancy using a fluorescence activated cell sortor. The CD16-CD56bright NK cell population occupies a major population in the decidual MNC, in contrast to a very small population (< 1%) in the peripheral blood MNC. These decidual CD16-CD56bright NK cells produced a large amount of IL-8, i. e., mean of 96.7 +/- 19.8 ng/ml in the 24 hr-cultured supernatants without any stimulant, which was comparable to the IL-8 production by LPS-stimulated peripheral blood MNC. Most of the IL-8 was ascribable to the production from decidual CD16-CD56bright NK cells. Intracytoplasmic IL-8 in the decidual CD56bright NK cells was also detected by flow cytometry. RT-PCR methods confirmed IL-8 mRNA expression in this population, while no or very scarce expression of IL-1 alpha and IL-1 beta mRNA was observed. The present study is a first observation revealing that decidual CD16-CD56bright NK cells express IL-8 mRNA and produce IL-8.

Antigens, CD↗

PubMed1994

Clinicopathological study of proliferating cell nuclear antigen (PCNA) of hepatocytes in primary biliary cirrhosis.

The DNA synthesis activities of hepatocytes in primary biliary cirrhosis (PBC) and other chronic liver diseases and control subjects were examined by staining proliferating cell nuclear antigen (PCNA) with anti-PCNA monoclonal antibody. The number of PCNA-positive cells (PCNA value) was significantly higher in PBC (375 +/- 281 parts per thousand; ppt) than in other chronic liver diseases, i.e., chronic hepatitis (95 +/- 83 ppt), liver cirrhosis (72 +/- 71 ppt), and alcoholic liver disease (73 +/- 56 ppt), and in control subjects (11 +/- 14 ppt). The PCNA value of PBC in stages I-III of Scheuer's classification was remarkably high, while in stage IV it was low. Even in identical, Scheuer's stages, the PCNA value of PBC was higher in patients who were not given ursodeoxycholic acid (UDCA) than in those who received UDCA. In identical patients, the PCNA value was lowered significantly after UDCA treatment. It was concluded that the DNA synthesis activity of PBC in stages I-III was accelerated and that UDCA can alleviate the abnormality in DNA synthesis activity.

Chronic Disease↗

PubMed1994

A study of CD45RO, CD45RA and CD29 antigen expression on human decidual T cells in an early stage of pregnancy.

The decidua is the place where the fertilized egg is implanted and where the immunocompetent cells of the mother come into direct contact with genetically disparate cells of the conceptus. Although the T cells in the decidua are exposed to fetal antigens, the fetus is not rejected by maternal immunocompetent cells. In the present study, we examined surface markers to determine whether the T cells in the human decidua are naive T cells without or memory T cells with a history of antigen stimulation. Although few T cells were present in the decidua, as compared to the peripheral blood, CD45RO+, CD29+ and CD45RA- CD4+ T cells as well as CD45RO+, CD29+ and CD45RA- CD8+ T cells, which are considered to be memory T cells, were in the majority, with only small numbers of CD45RO-, CD29- and CD45RA+ CD4+ and CD8+ cells, which are naive T cells, present. Also, the decidual mononuclear cells secreted IL-2 and IL-4. Since IL-4 is secreted only by memory T cells, it is suggested that in the decidua memory T cells increase in number and secrete cytokines, thereby in some way influencing the phenomenon of fertility.

Antigens, CD↗

PubMed1994

Macrophage colony-stimulating factor induces the growth and differentiation of normal pregnancy human cytotrophoblast cells and hydatidiform moles but does not induce the growth and differentiation of choriocarcinoma cells.

In the present study, we examined whether or not macrophage colony-stimulating factor (M-CSF; CSF-1) is involved in the growth and differentiation of human chorionic, hydatidiform mole and choriocarcinoma cells. M-CSF promotes the growth of early gestation chorionic cells, hydatidiform mole cells, and a human term placenta cell line (tPA30-1). However, the growth of choriocarcinoma cells, BeWo, Jar, Jeg-3, and NUC-1, was not influenced at all by M-CSF. M-CSF promoted the secretion of human chorionic gonadotropin (hCG) and human placental lactogen (hPL), which are secreted from differentiated trophoblast, from early gestation chorionic cells and from hydatidiform mole cells. However, the secretion of hCG and hPL from choriocarcinoma cells was not affected by M-CSF. When M-CSF localization was examined by immunohistochemical staining, M-CSF was detected in chorionic and hydatidiform mole cells, but was absent in choriocarcinoma cells. These results suggest that the growth and differentiation of normal chorionic and hydatidiform mole cells are M-CSF-dependent, while the growth and differentiation of choriocarcinoma cells are not.

Base Sequence↗

PubMed1994

Molecular characterization of intact, but cryptic, flagellin genes in the genus Shigella.

Flagellin genes (fliC) were detected in two species of the genus Shigella. The fliCSF gene cloned from Shigella flexneri produced normal-type flagella in an Escherichia coli delta fliC strain while the fliCSS genes from two Shigella sonnei strains produced curly-type flagella and their expression is repressible by Salmonella FljA repressor. The fliCSF gene (1650 bp) shared high similarity with the E. coli fliCE gene not only in the 5' and 3' constant sequences but also in the upstream and downstream sequences. The fliCSS genes (1572 bp) shared high similarity with the Salmonella typhimurium fliCS gene in the operator and 3' constant sequences and also shared high similarity with the fliCE gene in the downstream sequence, suggesting that the fliCSS gene has undergone horizontal transfer and recombination. Differences in nucleotide sequences of the central variable regions among the four fliC genes, including fliCE and fliCS, suggest that they started differentiation in each lineage approximately 80 million years ago. Loss of motility in Shigella seems to be evolutionarily a recent event.

Amino Acid Sequence↗

PubMed1993

Coexistence of somatic and germ-line mutations of APC gene in desmoid tumors from patients with familial adenomatous polyposis.

Desmoid tumors, which are locally invasive with recurrence but without metastasis, are frequently observed in patients with familial adenomatous polyposis after abdominal surgery or during pregnancy. This study analyzed mutation of the adenomatous polyposis coli gene in 8 desmoid tumors from 7 familial adenomatous polyposis patients using polymerase chain reaction-single-strand conformation polymorphism and the direct sequencing method. Seven somatic mutations, 1 somatic allele loss, and 6 germ-line mutations were detected. The majority of adenomatous polyposis coli gene mutations were deletions of 1 to 19 base pairs in exon 15, and all mutations led to the formation of stop codons. A somatic mutation with repetition of 82 base pairs from codon 1399 to 1426 was also observed in a desmoid, which was most likely caused by an error during replication or repair replication. No mutation was detected in exons 1 to 2 of H-ras, K-ras, and N-ras genes and in exons 5 to 8 of p53 gene, in these tumors. The simultaneous existence of somatic and germ-line alterations of adenomatous polyposis coli gene observed in all 8 tumors strongly suggests that inactivation of both alleles of adenomatous polyposis coli gene is involved in the development of desmoid tumors.

Adenomatous Polyposis Coli↗

PubMed1993

Purification and molecular cloning of chymase from human tonsils.

A chymotrypsin-like protease was purified to homogeneity from human tonsils by a series of chromatographic procedures. The purified enzyme gave a single protein band with an apparent molecular mass of 30 kDa on SDS-PAGE. The sequence of the first 21 amino acids at the N-terminus of the enzyme was determined. A cDNA for the enzyme was cloned by PCR amplification from extracted tonsillar mRNA using a supposed N-terminal oligonucleotide primer and a conserved C-terminal primer of the chymase family. The deduced amino acid sequence of the isolated clone was identical to that of human chymase in connective tissue-type mast cells from heart except for a Ser instead of a Cys at the N-terminal 7th position.

Amino Acid Sequence↗

PubMed1993

The effect of interleukin 2 and transforming growth factor-beta 2 (TGF-beta 2) on the proliferation and natural killer activity of decidual CD16- CD56bright natural killer cells.

The present study, using flow cytometry, demonstrated that CD16- CD56bright natural killer (NK) cells, which are abundant in the decidua, have both interleukin-2 receptor alpha (IL-2R alpha) and interleukin-2 receptor beta (IL-2R beta). The NK activity and DNA synthesis of CD16- CD56bright NK cells were markedly elevated even by treatment with small amounts of IL-2. These results indicate that decidual CD16- CD56bright NK cells possess a high-affinity receptor for IL-2. Transforming growth factor-beta 2 (TGF-beta 2), which is contained in the decidua and is thought to serve as a major immunosuppressive factor, reduced the NK activity of decidual CD16- CD56bright NK cells, but it hardly affected the IL-2-induced augmentation of the NK activity or DNA synthesis of decidual CD16- CD56bright NK cells. The conclusion has therefore been reached that once IL-2 is produced in the decidua, the IL-2-induced potentiation of the NK activity of decidual CD16- CD56bright NK cells cannot be suppressed by TGF-beta 2.

Antigens, CD↗

PubMed1993

Beta 1 integrins mediate chondrocyte interaction with type I collagen, type II collagen, and fibronectin.

Chondrocytes isolated from the cephalic region of sterna from 14-day-old chick embryos used beta 1 integrins and required either Mg2+ or Mn2+ for attachment to plates coated with type I collagen, type II collagen, and fibronectin. beta 1 integrin was concentrated in adhesion plaques of the chondrocytes plated on type I collagen, type II collagen, and fibronectin substrates. Chondrocytes expressed at least 3 alpha-subunits, including alpha 3, alpha 5, and putative alpha 2. alpha 5, but not alpha 3, had a higher molecular weight in chondrocytes than in fibroblasts. Levels of alpha 3 and alpha 5 were about 25-30% of that in fibroblasts. When the chondrocytes were cultured in the presence of ascorbate in suspension, the cells aggregated into clusters. This aggregation was dependent on beta 1 integrin and type II collagen.

Amino Acid Sequence↗

PubMed1993

Nucleotide sequence and regulated expression of the Salmonella fljA gene encoding a repressor of the phase 1 flagellin gene.

The nucleotide sequence of Salmonella abortus-equi fljA, which together with the phase 2 flagellin gene constitutes the fljBA operon and encodes the repressor for the phase 1 flagellin gene fliC, was determined. The repressor was predicted to be a basic protein consisting of 179 amino acid residues (M(r) = 20419 Da) encoded by ORFII. This was confirmed by the fact that host fliC is repressed by plasmid-encoded ORFII, which indeed expresses a 20 kDa product as determined by urea SDS-polyacrylamide gel electrophoresis. An amino acid sequence capable of forming a helix-turn-helix type of structure was predicted in the C-terminal region of FljA. A rho-independent intercistronic terminator was detected between fljB and fljA. Chloramphenicol acetyltransferase (CAT) assays of fusions indicated that the terminator is capable of reducing expression of fljA to the level of a few percent, relative to fljB in broth cultures and to 1% in M9 glycerol cultures.

Amino Acid Sequence↗