PubMed Health⌕ Search

Biomedical subjects

M Seki

Publications and source records attributed to M Seki.

At least 289 records · Page 16Linked to original sources
PubMed1991

Radiation-induced myeloid leukemia in C3H/He mice and the effect of prednisolone acetate on leukemogenesis.

We found that the incidence of spontaneous myeloid leukemia in C3H/He male mice was less than 1%, but it could be increased considerably by total-body X irradiation. The induction of myeloid leukemia was seen to increase after doses from 0.47 Gy (3%) to 2.84 Gy (23.9%), and then decrease after a dose of 4.73 Gy (13.6%). The administration of prednisolone acetate (synthesized glucocorticoid) after irradiation resulted in a significant increase in the incidence of myeloid leukemia from 23.9 to 38.5% after a dose of 2.84 Gy; however, corticosterone, a glucocorticoid secreted by cells, did not have such an enhancing effect.

Animals↗
PubMed1991

[Clinicopathological study on the intramural metastasis of the esophageal cancer].

Intramural metastasis and microscopical lymphatic permeation (distant-ly) distant more than 5mm from primary lesion were evaluated clinicopathologically in 207 patients with esophageal cancer, to reveal intramural lymphatic metastasis in esophageal cancer. Thirty-one lesions of intramural metastasis in 21 patients (10%) and 85 distant-ly lesions in 19 patients (9%) were observed. Both lesions existed mainly in lpm or sm layer and located within 5cm from primary lesion. As a direction of metastasis, intramural metastasis existed almost equivalently oral and anal from primary lesion, but distant-ly existed slightly more frequently in anal direction. When intramural metastatic lesion was recognized oral from primary lesion, lymph node involvement of the upper mediastinum was present in 67% of cases. On the other hand, intramural metastasis was seen anal from primary lesion and lymph node involvement of upper paragastric region was present in 100% of cases. Patients with intramural metastasis showed poor prognosis of one year of 50% survival period.

Esophageal Neoplasms↗
PubMed1991

[The effects of Cepharanthin on the recovery of hematopoietic stem cells after X-ray irradiation].

Administration of Cepharanthin (ceph) resulted in a significant acceleration of the recovery from leukopenia in 5-Gy X-ray irradiated mice. Then we examined the function of ceph on the recovery of hematopoietic stem cells after irradiation. The number of GM-CFU (granulocyte-macrophage committed stem cells) in the femur and spleen increased significantly in ceph compared to phosphate buffer solution administered groups. However, the time course of the recovery of GM-CFU did not differ between the two groups. These enhancing effects of ceph on GM-CFU were not observed when it was added to a bone marrow culture system. Therefore, the accelerating effects of the recovery from leukopenia after irradiation appears to be an indirect function of ceph.

Alkaloids↗
PubMed1991

[A study on hyperprolactinemia in female patients with alcoholics].

The clinical signs and symptoms of sexual dysfunction with amenorrhoea, loss of libido and infertility, are frequently found in chronic alcoholic women. But few investigations have been made concerning hormonal changes in fertile aged women experiencing sexual dysfunction. In order to assess prolactin levels of fertile-aged women with alcoholism under 40 years of age-excluding those with liver cirrhosis were surveyed. We found that many of them (82.6%) had moderate elevations of plasma prolactin. Hyperprolactinemia is commonly associated with amenorrhoea and hypogonadism. An acute alcohol loading experiment was conducted on 6 healthy female volunteers in luteal phases of their menstrual cycles in order to evaluate the effects of alcohol on the hypothalamo-pituitary-ovarian axis. Evidence was obtained that alcohol intake caused transient hyperprolactinemia. The present results indicated that hyperprolactinemia can occur with high frequency among alcoholic women and this causes sexual dysfunction and ovarian dysfunction. The etiology of hyperprolactinemia could not be explained solely by the direct action of alcohol, rather, liver dysfunction must be implicated.

Adult↗
PubMed1990

Genetic changes and histopathological types in colorectal tumors from patients with familial adenomatous polyposis.

Loss of heterozygosity (LOH) and K-ras mutation were analyzed in 111 colorectal polyps and 26 invasive carcinomas from 40 patients with familial adenomatous polyposis of distinct histopathological types. LOH, being less than 2% in moderate adenomas, was detected on chromosome 5q (20%) in severe adenomas, on 5q (26%) and 17p (38%) in intramucosal carcinomas, and on 5q (52%), 17p (56%), 18 (46%), and 22q (33%) in invasive carcinomas. LOH on chromosome 5q occurred most frequently in the region close to the APC gene both in adenomas and carcinomas, and a loss of the normal allele of the APC gene was demonstrated in 3 cases. K-ras mutation markedly increased in the step of development from moderate (11%) to severe (36%) adenomas. These results suggest the following mechanisms for the development of colon tumors in patients with familial adenomatous polyposis: (a) the heterozygous mutant/wild-type condition at the APC gene causes formation of mild or moderate adenoma; (b) the loss of the normal allele in the APC gene leads to a change from moderate to severe adenoma; (c) LOH on chromosome 17p contributes to the conversion of adenoma to intramucosal carcinoma; (d) LOH on other chromosomes, such as 18 and 22q, are involved in the progression of intramucosal carcinoma to invasive carcinoma; and (e) K-ras mutation may also affect the development of moderate to severe adenoma.

Adenomatous Polyposis Coli↗
PubMed1990

Expression and function of a 90-kilodalton homodimeric molecule (10D1 antigen) on human thymocytes.

The 10D1 Ag is a 90-kDa homodimeric molecule specifically expressed on a subpopulation of human T cells, and is involved in an alternative pathway of T cell activation. In the present study, we have examined the expression and function of the 10D1 Ag on human thymocytes. Three-color FMF analysis showed that the 10D1 Ag was highly expressed on minor but distinct subpopulations of double-negative and CD4 single-positive thymocytes, and weakly on a part of double-positive thymocytes, but not on CD8 single-positive thymocytes. In double-negative thymocytes, the vast majority of 10D1+ cells were immature thymocytes of CD7+2+3- phenotype. Interestingly, 10D1 mAb could induce the proliferation of CD4 single-positive thymocytes in the presence of goat anti-mouse Ig to cross-link the 10D1 Ag. The treatment of thymocytes with OKT4 mAb plus C but not with OKT8 mAb plus C totally abrogated the proliferative response induced by 10D1 mAb, indicating that the 10D1-responsible thymocytes were of CD4+8- phenotype. This 10D1 mAb-induced thymocyte proliferation was perfectly dependent on the endogenous IL-2/IL-2R system since a complete inhibition was observed with anti-IL-2 and anti-IL-2R mAb. The proliferating CD4 single positive thymocytes predominantly expressed the IL-2R alpha (p55) but not a detectable level of the IL-2R beta (p75). These results indicate that, although the 10D1 Ag can be detected on the CD7+2+3-4-8- thymocytes, its functional expression is restricted to a minor more mature CD4+ thymocyte population as well as in peripheral blood T cells, and the implications of these findings are discussed.

Antibodies, Monoclonal↗
PubMed1990

Detection of C3bBb-stabilizing activity (C3 nephritic factor) in the serum from patients with membranoproliferative glomerulonephritis.

It is known that membranoproliferative glomerulonephritis (MPGN), hypocomplementaemia and C3 nephritic factor (C3NeF) are closely related to each other, and the presence or absence of C3NeF in the serum is important for evaluating the nature of MPGN. However, some difficulties have been encountered in detecting this factor and therefore a new assay permitting the direct detection of C3NeF without purifying IgG from the patient's serum has been devised. Using this assay method, C3bBb-stabilizing activity was observed even in sera from MPGN patients who were non-hypocomplementaemic. Furthermore, among 98 cases with hypocomplementaemia. C3NeF was found to be absent in 66 cases.

Complement C3 Convertase, Alternative Pathway↗
PubMed1990

Activin A stimulates meiotic maturation of the rat oocyte in vitro.

The effect of activin A on meiotic maturation was analyzed in oocytes from immature rats treated with PMSG. Activin A, which was purified as the erythroid differentiation factor, accelerated the maturation of not only follicle-enclosed oocytes and oocyte-cumulus complexes, but also denuded oocytes, as measured by an increase in the percentage of oocytes with germinal vesicle breakdown (GVBD). Oocyte maturation was not accelerated by activin A in the presence of the inhibitor of GVBD such as cyclic-AMP. These results showed activin A is a potent in vitro stimulator of oocyte maturation.

Activins↗
PubMed1990

DNA helicase and nucleoside-5'-triphosphatase activities of polyoma virus large tumor antigen.

Polyoma virus large tumor antigen (PyV T antigen) has been purified to near homogeneity by immunoaffinity column chromatography. We have detected DNA helicase and ATPase (nucleoside-5'-triphosphatase) activities in the purified PyV T antigen fraction and characterized these activities. The ATPase activity was stimulated about 2-fold by poly(dT), which was the most effective stimulator among the synthetic polynucleotides tested. Natural nucleic acids, such as calf thymus native and heat-denatured DNA, and single-stranded circular fd DNA were also effective, but the degree of stimulation was less than 1.5-fold. The basal and poly(dT)-stimulated ATPase activities showed similar preference for nucleoside 5'-triphosphates, requirement for divalent cations, and pH optima. The preference for nucleoside 5'-triphosphates was ATP, dATP greater than CTP, UTP much greater than GTP. The only difference observed between the two activities was salt sensitivity. The basal ATPase activity was resistant to KC1 up to 300 mM. In contrast, poly-(dT)-stimulated activity was reduced to the level of basal activity at 300 mM KC1. DNA helicase activity required divalent cations and was dependent on hydrolysis of ATP. The activity showed similar preference for nucleoside 5'-triphosphates, requirement for divalent cations, and pH optimum as the two ATPase activities, and the salt sensitivity of DNA helicase activity was similar to that of poly(dT)-stimulated ATPase activity. The helicase activity was inhibited competitively by the addition of single-stranded or double-stranded DNA, and a relatively high inhibitory activity was observed with poly [d(A-T)]. The PyV T antigen helicase was found to migrate in the 3' to 5' direction along the DNA strand to which the protein bound.

Adenosine Triphosphatases↗
PubMed1990

A rapid turbidimetric immunoassay for serum antistreptolysin-O.

We designed a rapid, quantitative turbidimetric immunoassay for serum antistreptolysin-O (ASO), based on the immunoprecipitating velocity with purified streptolysin-O (SLO), which can be measured turbidimetrically at 340 nm. The assay system involves polyoxyethylene mono-p-nonylphenyl ether to accelerate and enhance the immunoprecipitation reaction. No antibody excess phenomenon is observed, up to 1,700 U/ml. Grossly icteric sera can be assayed. Patient sera gave acceptable results. Free cholesterol offers no interference. The standard curve is linear for values up to 800 U/ml. Results measured by the proposed method and those by the conventional microtitration method correlated well. Analytical recovery averaged 90.1% (80.3%-102.5%). Within-run and day-to-day CVs ranged from 2.1% to 3.5% and from 2.5% to 6.9%, respectively. Working SLO is stable for at least 15 days at 4 degrees C. The proposed method has proven to be superior to other available methods for measuring serum ASO.

Antistreptolysin↗
PubMed1990

Intracellular processing and immunogenicity of the envelope proteins of human T-cell leukemia virus type I that are expressed from recombinant vaccinia viruses.

Two types of recombinant vaccinia viruses (VVs) expressing the env gene of the human T-cell leukemia virus type I (HTLV-I) were reported previously. One recombinant VV, WR-proenv1, synthesized the authentic env protein. In the other recombinant VV, WR-env17, the env gene was inserted within the signal sequence of the VV hemagglutinin (HA) gene, so that the reading frame for the env gene was in phase with that for the HA gene. Comparative studies were performed on the mode of expression and processing of the env proteins in relation to their immunogenicity. In WR-env17-infected cells, translation was initiated exclusively from the initiation methionine of the HA to produce nascently the chimeric env protein, including the altered HA signal peptide. Both this altered HA signal peptide and the internalized env signal peptide functioned as insertion signals for the endoplasmic reticulum. Although about half of the nascent chimeric protein was cleaved at the carboxyl terminus of the internalized env signal peptide to produce the authentic env protein, the other half was cleaved at the carboxyl terminus of the altered HA signal peptide alone to synthesize the chimeric protein. These events led to a less efficient transport of the env protein produced by WR-env17 from the rough endoplasmic reticulum to the Golgi apparatus than that of the authentic env protein synthesized by WR-proenv1. The efficiency of the processing and transport of the env protein affected the immunogenicity of these two recombinant VVs.

Animals↗
PubMed1990

Hemadsorption and fusion inhibition activities of hemagglutinin analyzed by vaccinia virus mutants.

Vaccinia virus IHD-J strain induces hemagglutinin (HA) on the surface membrane of infected cells and does not elicit cell-cell fusion (F-). We isolated 21 independent hemadsorption-negative (HAD-) mutant viruses from IHD-J and five HAD+ revertants from one of these mutants. Of the 21 mutants, 19 that synthesized either no or little HA at the cell surface caused cell-cell fusion (F+), whereas none of the five revertants that synthesized HA at the cell surface induced cell-cell fusion. Furthermore, anti-HA monoclonal antibody B2D10 induced extensive polykaryocytosis of IHD-J-infected cells and suppressed the ability of the IHD-J-infected cell extract to inhibit the polykaryocytosis induced by IHD-W. The other 2 of the 21 HAD- mutants, B1 and A2, which induced HAs at the cell surface, showed F- and F+ phenotype, respectively. The HA molecule of mutant B1 had a single amino acid substitution of Lys for Glu-121 in its extracellular domain, whereas that of mutant A2 had a single substitution mutation of Tyr for Cys-103. We conclude that the vaccinia HA is a fusion inhibition protein, that the active sites for the two activities reside separately in its extracellular domain, and that cysteine-103 is important in forming the proper tertiary structure of the protein to exert both activities.

Animals↗
PubMed1990

[Induction and functional analysis of gamma delta TCR-bearing T cells from human tonsil by Streptococcus pyogenes stimulation].

The killer cell characteristics of gamma delta TCR-bearing T cells induced from human tonsil by streptococcus pyogenes stimulation were examined. Immunohistologic staining of tonsil showed that gamma delta TCR-bearing T cells were mainly located in the interfollicular area connected with stratified squamous epithelium. Streptococcus pyogenes could induce the proliferation of gamma delta TCR-bearing T cells from tonsil in the presence of low-dose of IL-2. This streptococcus pyogenes-induced gamma delta TCR-bearing T cell proliferation was likely to be independent on the IL-2/IL-2R system since an obvious inhibition was not observed with anti-IL-2 and anti-IL-2R mAbs. More importantly, these gamma delta TCR-bearing T cells exhibited cell-mediated cytotoxic activity in a 4 hr 51 Cr-release assay. In addition, immunocytochemical staining revealed that these cells contained a killer protein perforin. These results demonstrate that gamma delta TCR-bearing T cells from tonsil exhibit typical killer cell characteristics. These data also suggest that gamma delta TCR-bearing T cells in human tonsil may play a cytotoxic role in protecting the integrity of tonsil from infection.

Cytotoxicity, Immunologic↗
PubMed1990

[The management of drooling in patients with cerebral palsy--submandibular duct relocation].

Drooling is a significant problem demonstrated by individuals of all ages with a variety of etiologies such as neurological disorders, cerebral palsy, mental retardation and others. Persistent drooling not only creates troublesome hygienic problems for patients, teachers, nurses, and playmates because of the constant soiling of clothes, toys, and work materials, but also causes an odor from their clothing and bibs. The older patient with normal cognition is disturbed by the drooling and may become depressed and reclusive. Successful management of drooling alleviates these problems, improves appearance and self-esteem and significantly reduces the time involved in the care of the sufferers. The author, who had studied at the University of Toronto for 2 years, acquired the technique of submandibular duct relocation under the guidance of Dr. Crysdale. We carried out the surgical procedure of submandibular duct relocation for drooling on six patients who had cerebral palsy. The surgical procedure resulted in a dramatic decrease in drooling and odor levels. All of them improved in appearance, and the time involved in the care of the suffers was significantly reduced. The complication of ranula, however, appeared in two cases, which suggested a much higher frequency than that in the report of Crysdale. It seems that a detailed explanation to parents and teachers about the advantages and disadvantages of submandibular duct relocation is important.

Cerebral Palsy↗
PubMed1990

[Study for improvement of oral health among the elderly. Present status of dental care service at elderly homes].

Since the dental environment at a living place could potentially become a factor causing a need for dental care, all 33 elderly homes (27 of which responded to the survey) in Tokyo were investigated for the purpose of identifying the present status of dental care service and the problems existing at these homes. The following are the obtained conclusions. 1. The rate of homes with dental care facilities is as low as 19.2%, and cooperation by dental care institutions, including house calls, is ensured only at the low rate of 11.1%. As a result, usually patients visit the dental institutions. 2. The involvement of the dental staff, including part-time, was 44.4%, less than half of the homes surveyed. The homes wishing to employ or receive service from dental staff accounted for 76.9%. The homes also expected them to be engaged in the activities of overall oral hygiene, including not only dental treatment, but also participation in the planning of oral hygienic management. However, 23.1% of the respondents did not wish to employ any dental staff or receive any such service. 3. Specific programs for the guidance and management of oral hygiene were not observed. Homes that conducted dental examination periodically and those that carried out activities related to oral hygiene during Dental Health Week were also lacking. In addition, the homes which had assigned personnel responsibility for oral hygiene represented only 12.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗