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Biomedical subjects

T Enomoto

Publications and source records attributed to T Enomoto.

At least 163 records · Page 9Linked to original sources
PubMed1996

Effects of a small dose of triazolam on P300 and resting EEG.

The aim of the present study was to clarify whether cognitive impairments caused by benzodiazepines (BDZs) are a consequence of their specific direct effects on cognitive function or whether they are explained as secondary effects of increased sleepiness. Ten healthy men (mean age, 33.9 years) participated in two experimental sessions in a randomized cross-over, double-blind study: in one session subjects were given a placebo and in the other they were given 0.125 mg triazolam (TRZ). Each experimental session was conducted on 1 day. After a pre-drug EEG recording and an event-related potential (ERP) recording, under an oddball paradigm, subjects took the TRZ or placebo orally at 1000 hours. Thereafter, EEG and ERP recording sessions, following the same procedure as the pre-drug sessions, were conducted at 1, 2, 4, 6 and 8 h after drug administration. The EEG and ERP recordings from Cz and Pz referred to the bilaterally linked ear electrodes were used. We found that P300 latency was significantly prolonged in TRZ condition at 2 h (Pz) and 4 h (Cz and Pz) after TRZ, and that the P300 amplitude was significantly reduced at 2 h (Cz and Pz) and 4 h (Pz) after TRZ, compared to the same times after placebo. The absolute power values for the theta (4-7 Hz), alpha 1 (8-9 Hz), and alpha 2 (10-12 Hz) bands did not differ at any measurement time between the treatments. Only the beta band (13-19 Hz) power value was significantly elevated after the TRZ administration (versus placebo). No significant sedative effects were detected in subjective measurements. These results indicate that a single oral dose of 0.125 mg TRZ caused cortical changes without distinct general sedation or subjective sleepiness.

Adult↗
PubMed1996

Antibody to gp39, the ligand for CD40 significantly inhibits the humoral response from Graves' thyroid tissues xenografted into severe combined immunodeficient (SCID) mice.

Experimental evidence suggests that interference with gp39-CD40 interactions may have therapeutic potential in prevention of certain autoimmune disorders (i.e., collagen-induced rheumatoid arthritis). The binding between CD40 expressed on mature B cells and CD40 ligand (CD40L, gp39) transiently expressed on activated T helper cells (Th) further stabilizes the interactions (between Th and B cells) and co-ordinates the responses of the interacting cells during antigen presentation, and is essential for thymus-dependent humoral immunity. Graves' disease is the most common form of hyperthyroidism, in which hyperactivity of the thyroid gland is due to an autoantibody directed against the thyrotropin receptor (TSHR). The main objective of our study was to determine the role of interactions between gp39 and CD40 in "an established" human Graves' disease (GD). Severe combined immunodeficient (SCID) mouse served as a vehicle for human Graves' thyroid tissue. This experimental setting allows us to study, observe, and immunomodulate human autoimmune tissue in so called in vivo condition. We studied the effects of ip administration of anti-gp39 mAb on humoral response, thyroid function tests, expression of adhesion molecules, and HLA-DR on human thyrocytes and histopathological changes from human GD thyroid tissue xenografts. GD thyroid tissue from 4 patients was xenografted into 20 SCID mice (0.8 g/mouse). Human immunoglobulin G (IgG) levels became detectable in SCID mice 1 week after xenograftment. Ten SCID mice were sequentially administered anti-gp39 mAb (250 micrograms/mouse/ dose) ip every 4 days until the end of the experiment. Ten control animals were injected with vehicle (PBS) in similar fashion. Blood samples were taken every 2 weeks from the tail veins for measurement of the humoral response [human IgG, thyroid-stimulating antibody (TSAb), antithyroperoxidase (anti-TPO), and antithyroglobulin (anti-Tg), Abs], and thyroid function tests. After 8 weeks, animals were sacrificed and thyroid tissue was examined histologically. The humoral response from the intrathyroidal lymphocytes was measured and the tissue morphology of GD was preserved during the 8-week period in phosphate-buffered saline (PBS)-treated SCID mice xenografted with GD xenografts. However, administration of anti-gp39 mAb completely blocked or significantly decreased the humoral response in all treated animals. On the other hand, no significant histological changes were associated with the administration of anti-gp39 mAb. The degree of lymphocytic infiltration in thyroid tissue xenografts was comparable in both groups. Serum thyroxine values were normal in both groups. In spite of a profound immunosuppressive effect on the humoral response by directly blocking CD40-gp39 interactions in vivo, this did not result in complete deletion of the responding Th in the thyroid specimens.

Animals↗
PubMed1996

Application of clonal analysis. Differential diagnosis for synchronous primary ovarian and endometrial cancers and metastatic cancer.

Simultaneous involvement of the endometrium and the ovary by carcinoma is a familiar problem in the routine practice of surgical pathology. Such cases may be considered either examples of a single primary carcinoma with metastasis or as synchronous primary neoplasms. The distinction between these two possibilities is made based on clinicopathologic observations, and therefore may not be definitive. In the present study, the authors used molecular techniques to analyze the clonal composition of five cases of concurrent adenocarcinomas of the endometrium and ovary that were clinicopathologically diagnosed as synchronous primary tumors. Patterns of X-chromosome inactivation, mutations in the K-ras gene, mutations or allelic loss of the p53 gene, or human papillomavirus detection were identical in both endometrial and ovarian lesions in three of the cases suggesting that those three cases represented single primary tumors with metastases. In both of the other two cases, the patterns of X-chromosome inactivation clearly demonstrated the presence of independent primary tumors. The application of molecular technology may play an important role for the differential diagnosis between synchronous primary carcinomas and a single carcinoma with metastasis.

Adult↗
PubMed1996

Variant mutational activation of the K-ras oncogene in renal mesenchymal tumors induced in newborn F344 rats by methyl(methoxymethyl)nitrosamine.

Renal mesenchymal tumors were induced at high incidence in F344 rats by a single intraperitoneal injection of methyl(methoxymethyl)nitrosamine (DMN-OMe) within 48 h after birth. DNAs from 18 of 35 mesenchymal tumors contained transforming ras sequences in NIH3T3 transfection assays: K-ras (17/18) or N-ras (1/18). Single-stranded conformational polymorphism analysis or dideoxy sequencing of polymerase chain reaction-amplified K-ras gene fragments revealed that these neoplasms contained a variety of activating mutations in the K-ras oncogene. Alterations in codon 12 predominated and included GGT --> GAT transitions, GGT --> GTT or TGT transversions, and previously reported insertion mutations, although some tumors expressed more than one mutation and the pattern of mutations even varied within tumors. Mutations were also found in exons 2 and 3. In addition, tumor transplantability into syngeneic hosts correlated positively and significantly with K-ras activation. Renal mesenchymal tumors with transforming mutations in exon 1 were often successfully passaged (10/12) while tumors which lacked mutations in exon 1 were infrequently transplantable (2/14). While the observed base substitutions in K-ras are consistent with adduct formation, the presence of insertion mutations and intratumor heterogeneity of alterations suggest that ras activation in DMN-OMe-induced tumors is not necessarily an early event in tumorigenesis.

Animals↗
PubMed1996

Association between atopic asthma and a coding variant of Fc epsilon RI beta in a Japanese population.

A genetic association study was performed with coding variants of Fc epsilon RI beta in relation to atopic and non-atopic asthma in a Japanese population (n = 400). A coding variant of Gly237Glu in exon 7 of Fc epsilon RI beta gene showed association with atopic asthma (OR = 3.00, chi 2 = 5.10, p < 0.03), but not with non-atopic asthma; this was seen particularly in childhood asthma (OR = 3.92, chi 2 = 8.66, p < 0.005). This variant is also associated with very high total serum IgE levels (> mean + 3 SD, OR = 8.56, chi 2 = 46.2, p < 0.0001), but not any allergen specific IgE. However, Leu181lle, another variant of Fc epsilon RI beta related to atopy in British and Australian populations, was not found in this Japanese population. These results suggest that variants of Fc epsilon RI beta may be an important genetic cause of the atopic asthma.

Adult↗
PubMed1996

Alterations in left ventricular wall stress and coronary circulation in patients with isolated systolic hypertension.

OBJECTIVES: To study the alterations in cardiac function and coronary circulation in patients with isolated systolic hypertension (ISH). PATIENTS: Ten patients with a history of ISH were studied and findings were compared with those of seven normotensive subjects. All of the patients had angiographically normal coronary arteries. They underwent cardiac catheterization, and haemodynamic variables and coronary flow velocity were measured. All of the patients also underwent treadmill exercise testing. MAIN OUTCOME MEASURES: Left ventricular mass was evaluated by echocardiography. The coronary flow velocity data were obtained by using the intracoronary Doppler catheter technique. ST-segment depression was observed on the exercise electrocardiogram. RESULTS: Systemic vascular resistance did not differ, whereas total arterial compliance was decreased in the ISH patients versus the controls (P < 0.001). The left ventricular mass of the ISH patients was increased slightly, but their left ventricular systolic wall stress was greater than that of the controls (P < 0.01). The coronary flow reserve ratio and the ratio of diastolic to total coronary flow were decreased in the ISH patients versus the controls (P < 0.01). ST-segment depression on the exercise electrocardiogram was frequently observed in the hypertensive patients (80 versus 0% in control subjects, P < 0.01). CONCLUSIONS: Patients with ISH were characterized haemodynamically by a decrease in arterial compliance. They showed an increase in left ventricular systolic wall stress and also showed decreases in coronary flow reserve ratio and in the relative diastolic coronary flow. Such alterations observed in patients with ISH are detrimental to the heart and may contribute to a reduced exercise capacity and the induction of subendocardial ischaemia during exercise.

Adult↗
PubMed1996

Characterization of the properties of a human homologue of Escherichia coli RecQ from xeroderma pigmentosum group C and from HeLa cells.

We showed that DNA-dependent ATPase Q1 (DNA helicase Q1) from xeroderma pigmentosum complementation group C (XP-C) cells elutes from FPLC Mono Q column at higher concentrations of KCl than that from other human cells (35). We purified DNA helicase Q1 from XP-C and HeLa cells. The purified fractions of both cells contained a major polypeptide with a molecular mass of 73 kDa and had the same enzymatic properties, including salt- and temperature-sensitivity. Characterization using an anti-DNA helicase Q1 antibody indicated that this enzyme localized in the nuclei and was not modified by incorporating phosphate groups through phosphorylation and ADP-ribosylation. No interactions of DNA helicase Q1 with other proteins were indicated by immunoprecipitation of the helicase from crude extracts. No difference was observed in XP-C cells in intracellular localization of DNA helicase Q1, phosphorylation, and the interaction with other proteins as compared to HeLa cells.

Adenosine Triphosphatases↗
PubMed1996

Microtubule disruption induces the formation of actin stress fibers and focal adhesions in cultured cells: possible involvement of the rho signal cascade.

To obtain insight into the molecular dynamics and involvement of microtubules and the related signal molecules in the regulation of cell locomotion, we studied the influence of microtubule disruption on actin stress fibers and focal adhesion assembly in addition to cell morphology. We found that all microtubule-disrupting drugs including colcemid and vinblastine rapidly and reversibly induce the formation of actin stress fibers and focal adhesions containing vinculin, accompanied by activated cell motility in serum-starved Balb/c 3T3 cells. In contrast, taxol, a microtubule-stabilizing drug, completely inhibited these effects of the microtubule-disrupting drugs. A microinjection of C3 ADP-ribosyltransferase, a specific inhibitor of rho GTPase, blocked the stress fiber and focal adhesion assembly induced by the microtubule disruption. These results suggested that microtubules contain signal molecules that regulate the formation of stress fibers and focal adhesions by activating the rho signal cascade. We postulate that microtubule-releasing and stress fiber-inducing factors link the intrinsically variable and irregular actin filament dynamics to coordinated and directional locomotion in the process of cell movement.

3T3 Cells↗
PubMed1995

Microsatellite instability and alterations in the hMSH2 gene in human ovarian cancer.

The role of the replication error-positive (RER+) phenotype in the development of specific subtypes of sporadic ovarian carcinomas was examined by screening for the presence of microsatellite instability (MI) in 47 tumors. The overall frequency of ovarian MI was 17% only. However, MI occurred in 50% of the ovarian endometrioid-type tumors, which was significantly more often than in all the other histological subtypes combined (8%). Five of the 8 RER+ tumors exhibited most marked type I instability, possibly representing a different mechanism than for the remaining type 2 tumors. The cDNA of the mutation suppression gene hMSH2, the gene most often associated with MI, was screened for alterations in 8 MI-positive and 5 MI-negative ovarian tumors. Only 3 changes were found. Complete loss of hMSH2 mRNA expression was detected in I tumor, while another expressed only an abnormal transcript containing a deletion of exon 3. One additional RER+ serous adenocarcinoma contained a rare polymorphism with a non-conservative amino acid change. One of 8 RER+ tumors showed loss of heterozygosity at the hMSH2 loci. Genetic instability, caused in part by alterations in the hMSH2 gene, may play an important role in the sporadic endometrioid subtype of ovarian tumors. Other mutator-phenotype genes may be responsible for the remaining cases of RER+ ovarian tumors.

Base Sequence↗
PubMed1995

Stimulation of DNA synthesis by mouse DNA helicase B in a DNA replication system containing eukaryotic replication origins.

A number of DNA helicases have been isolated from mammalian cells, but their abilities to stimulate DNA replication accompanied with DNA unwinding have not been addressed so far. We constructed a model DNA replication system using the yeast autonomously replicating sequence (ARS) as the replication origin. In this system, SV40 T antigen as a DNA helicase assembles to the replication origin where the DNA duplex is unwound by torsional stress due to the negative supercoiling of template DNA, which leads to bidirectional DNA replication from the origin. We report here that DNA helicase B isolated from mouse FM3A cells can greatly stimulate DNA synthesis in this replication system in place of SV40 T antigen. DNA synthesis was dependent on the presence of single-stranded DNA binding protein (RP-A), DNA polymerase alpha/primase from mouse cells, and Escherichia coli DNA gyrase. DNA gyrase was required not only at elongation as a DNA swivelase but also at initiation to increase negative superhelical density of template DNA with the assistance of RP-A. A mammalian DNA fragment containing a replication initiation zone upstream of the c-myc gene as well as the yeast ARS fragment acted as a cis-element in this system using DNA helicase B. Both DNA helicase B and SV40 T antigen have the ability to extensively unwind the template DNA in the presence of RP-A and DNA gyrase, which may be crucial for stimulation of DNA synthesis in this system.

Adenosine Triphosphatases↗
PubMed1995

Stimulation of mouse DNA primase-catalyzed oligoribonucleotide synthesis by mouse DNA helicase B.

Many prokaryotic and viral DNA helicases involved in DNA replication stimulate their cognate DNA primase activity. To assess the stimulation of DNA primase activity by mammalian DNA helicases, we analyzed the synthesis of oligoribonucleotides by mouse DNA polymerase alpha-primase complex on single-stranded circular M13 DNA in the presence of mouse DNA helicase B. DNA helicase B was purified by sequential chromatography through eight columns. When the purified DNA helicase B was applied to a Mono Q column, the stimulatory activity for DNA primase-catalyzed oligoribonucleotide synthesis and DNA helicase and DNA-dependent ATPase activities of DNA helicase B were co-eluted from the column. The synthesis of oligoribonucleotides 5-10 nt in length was markedly stimulated by DNA helicase B. The synthesis of longer species of oligoribonucleotides, which were synthesized at a low level in the absence of DNA helicase B, was inhibited by DNA helicase B. The stimulatory effect of DNA helicase B was marked at low template concentrations and little or no effect was observed at high concentrations. The mouse single-stranded DNA binding protein, replication protein A (RP-A), inhibited the primase activity of the DNA polymerase alpha-primase complex and DNA helicase B partially reversed the inhibition caused by RP-A.

Adenosine Triphosphatases↗
PubMed1995

Association of human papillomavirus with malignant and premalignant lesions of the uterine endometrium.

The possible association of human papillomavirus (HPV) with endometrial hyperplasia and endometrial adenocarcinoma was investigated. DNA from frozen tissues of 30 endometrioid carcinomas of Japanese patients was tested for HPV DNA by Southern blot hybridization analysis. Screening with HPV type 58 probe under low stringency conditions showed the presence of HPV DNA in two of 30 endometrioid carcinomas. High stringency hybridization identified HPV type 16 in the two positive specimens. The presence of HPV was further analyzed by polymerase chain reaction (PCR)-Southern blot analysis of DNA from archival tissue blocks of the initial 30 endometrioid carcinomas as well as an additional 17 endometrioid carcinomas and 13 atypical hyperplasias of the endometrium from Japan and 38 endometrioid carcinomas from the United States. Polymerase chain reaction amplification using type 16-specific HPV primers for a portion of the E6 open reading frame was positive in six of 47 (13%) endometrioid carcinomas from Japan, including two in which HPV 16 was not detected by Southern blot analysis and two of 38 (5%) endometrioid carcinomas from the United States. Polymerase chain reaction amplification using L1 consensus sequence primers was positive for HPV in two of 13 (15%) endometrial hyperplasias, 13 of 47 (28%) endometrioid carcinomas from Japan, and six of 38 (16%) endometrioid carcinomas from the United States. Slot blot hybridization identified HPV type 16 in seven of the L1 PCR products, including all but one specimen testing positive for HPV type, 16 using E6 type specific primers. In situ hybridization was positive for HPVs 16/18 in glandular epithelial tumor cells in six of the PCR-positive specimens. An additional specimen showed staining for HPVs 16/18 in acellular luminal debris in association with squamous metaplasia of the tumor, but staining was negative in the glandular cells of the tumor. Human papillomavirus was not detected by in situ hybridization in the remaining specimen, which was PCR positive for HPV 16. In situ hybridization was weakly positive for HPVs 31/33/35 in one specimen and was weakly positive for HPVs 6/11 in benign endometrial epithelial cells but not in tumor cells of another specimen that tested positive for HPV by L1 PCR. Two dimensional gel electrophoresis performed on two specimens showed that HPV DNAs were integrated into cellular DNA with no episomal coexistence. These findings suggest that HPV, especially HPV 16, may play an etiologic role in a fraction of endometrioid adenocarcinomas.

Adult↗
PubMed1995

Loss of expression and loss of heterozygosity in the DCC gene in neoplasms of the human female reproductive tract.

In order to identify the possible role of the DCC gene in neoplasms of the human female reproductive tract, messenger RNA expression of the DCC gene was examined by reverse transcriptase-polymerase chain reaction, and expression of the DCC gene product was detected immunohistochemically. While histologically normal endometrium, cervical epithelium and ovary expressed detectable mRNA of the DCC gene, three of eight (37%) endometrial carcinomas, one of two (50%) cervical carcinomas and 9 of 22 (41%) ovarian malignant tumours had significantly reduced or negligible DCC expression, and another endometrial carcinoma and two other ovarian tumors underexpressed DCC when compared with histologically normal endometrial or ovarian tissues. Impaired DCC mRNA expression was detected more frequently in grade 3 ovarian epithelial tumours than in grade 1 tumours (P = 0.002). Loss of expression of the DCC gene product detected by immunohistochemistry significantly correlated with the loss of mRNA expression in ovarian carcinomas (P = 0.01 by chi-square test) or in both endometrial and ovarian carcinomas combined (P = 0.001). Loss of heterozygosity of the DCC gene was also evaluated by restriction fragment polymorphism analysis of the polymerase chain reaction-amplified DNA fragment. Loss of heterozygosity of the DCC gene was detected in one of seven (14%) informative cases of endometrial carcinomas, 1 of 11 (9%) informative cases of cervical carcinomas and two of six (33%) informative cases of ovarian tumours. These results demonstrate that inactivation of the DCC gene, especially by the loss of expression, plays a significant role in the aetiology of neoplasms of the human reproductive tract.

Adenocarcinoma↗
PubMed1995

Alteration of the p53 tumor suppressor gene and activation of c-K-ras-2 protooncogene in endometrial adenocarcinoma from Colorado.

The authors previously reported a significant frequency of activating point mutations in codon 12 and 13 of the K-ras gene in endometrial carcinoma and endometrial atypical hyperplasia from Osaka, Japan. They also showed that alterations of the p53 gene are found frequently in those tumors. This study was designed to reveal possible demographic differences in the prevalence of K-ras and p53 mutations in endometrial carcinoma. Tumor-enriched areas of paraffin-embedded histologic sections obtained through the Colorado Central Cancer Registry were isolated and extracted for DNA. Fragments amplified by polymerase chain reaction (PCR) were screened for transforming mutations in codon 12, 13, or 59-63 of K-ras by direct sequencing. Of 38 endometrial adenocarcinomas that were analyzed, K-ras activation was detected in 4 cases (11%), three in codon 12 (a single case with a GGT-->AGT transition, a single case with a GGT-->GAT transition, and a single case with a GGT-->TGT transversion) and one in codon 13 (a GGC-->GAC mutation). The prevalence of K-ras mutations was significantly lower in endometrial carcinomas from Colorado (4 of 38, 11%) than in those from Osaka, Japan (17 of 57, 31%; P = .02). Mutations in exons 5-8 of p53 were screened by PCR-SSCP analysis, and subsequently confirmed by direct sequencing. Mutations in the p53 gene were detected in 5 of 38 endometrial carcinomas from Colorado (13%), including a single base substitution mutation in 3 cases (60%) and a deletion mutation in 2 cases (40%). Mutations in the p53 gene were significantly more frequently found in G3 cancers (3 of 7, 43%) than G1-G2 cancers combined (2 of 31, 6%; P = .025). Although the prevalence of p53 mutations in endometrial carcinomas from Colorado was not significantly different compared to that from Osaka, Japan (9 of 40, 23%), a G:C-->A:T transition at a CpG site, which was the most common base substitution mutation among Japanese, was not included in any tumors from Colorado. A rare polymorphism in codon 213 (CGA-->CGG) was observed in three cases. These observations may indicate that genetic or environmental factors may significantly influence the pathway of endometrial carcinogenesis.

Adenocarcinoma↗
PubMed1995

Efficient replication of polyomavirus DNA in a cell-free system supplemented with Escherichia coli single-stranded DNA binding protein, which exhibits species-specificity in the requirement for DNA polymerase alpha-primase.

We established a modified cell-free system for polyomavirus (PyV) DNA replication, which was supplemented with Escherichia coli single-stranded DNA binding protein (SSB). DNA synthesis in this system was enhanced by 1.4- to over 15-fold depending upon the amount of cell extracts contained in the reaction mixture. By supplementing with E. coli SSB, we were able to reduce the amount of cell extracts in the reaction mixture, and to lower the concentrations of creatine phosphate and Tris, rendering this system more resistant to salts than the conventional PyV DNA replication system. The modified system was characterized using mutant cell extracts which had heat-inactivated DNA polymerase alpha. DNA synthesis in the system was dependent on PyV T antigen, the PyV origin of DNA replication, mutant cell extracts, and DNA polymerase alpha-primase complex purified from wild-type cells. The DNA polymerase alpha-primase complex was not replaced by DNA polymerase alpha, indicating that this system requires a functional DNA polymerase alpha-primase complex. This system exhibited species-specificity in the requirement for DNA polymerase alpha-primase; only mouse DNA polymerase alpha-primase but not human DNA polymerase alpha-primase functioned in this system.

Animals↗