Search PubMed⌕ Search

Biomedical subjects

K Sayama

Publications and source records attributed to K Sayama.

88 records · Page 5Linked to original sources
PubMed1989

Characterization of two possible forms of type IV collagen from human kidney cortex.

Type IV collagen was isolated from human kidney cortex according to the purification of mouse kidney type IV collagen (MKIVC) with minor modifications as described previously [Oikawa, T., et al. (1986) Chem. Pharm. Bull. 34, 789-797]. Chromatography of human kidney type IV collagen (HKIVC) on a column of DEAE-cellulose resulted in its separation into two fractions, i.e., one (HKIVC-1) passed through and the other (HKIVC-2) adsorbed to the column, similar to MKIVC. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Bio-Gel A-5m chromatography revealed that both HKIVC-1 and -2 differed from each other in the ratios of major and minor components. Amino acid analyses also demonstrated that there was a significant difference in the contents of several amino acid residues between both type IV collagens and their 80-kDa components, one of the major ones. These results indicate the possibility that there exist two forms of type IV collagen in human kidney.

Amino Acids↗
PubMed1986

Number of hits necessary for complement-mediated hemolysis.

The number of hits necessary for the C8 and C9 steps of immune hemolysis was reexamined with a previously unemployed experimental design, in which various numbers of EAC1-7, excess of the supplementary component and a constant amount of the component tested were incubated in a constant volume (Inoue et al. 1976. Infect. Immun. 13: 337). Our results were consistent with previous findings; the steps of guinea pig C8 and C9, the human C8 each followed a one-hit mechanism, while that of human C9 showed ka multi-hit response. When lysis of sensitized erythrocytes (EA) by normal human serum was analysed in a similar way, one-hit curves were obtained. This result, taken together with the above results, suggests that immune hemolysis occurs by a single lesion including a single C8 and multiple C9 in the case of human complement and that normal human serum contains sufficient excess of C9. On the other hand, when C9-deficient human serum was used for lysis of EA, multiple-hit curves were obtained. The mechanism of lysis by C5b-8 may differ from that by C5b-9.

Animals↗
PubMed1985

Complement profile in a C1 inhibitor deficient family.

Complement components and anaphylatoxins in a C1 inhibitor (C1INH) deficient family were studied. C4a was increased when C1INH was decreased, and C3a was increased in subjects with systemic lupus erythematosus (SLE)-like symptoms and with angioedema attacks. Danazol was effective in controlling the clinical as well as complement abnormalities including low CH50, C1INH and C4, which increased within 10 days after danazol treatment was started. Two-dimensional immunoelectrophoresis of C1INH showed that there was no functionally or electrophoretically abnormal C1INH present before or after danazol treatment. C3a and C4a were considered to play important roles in the pathogenesis of angioedema and associated SLE-like symptoms.

Anaphylatoxins↗
PubMed1984

Inhibition of immune precipitation by complement.

Normal human complement serum (NHS) inhibited precipitin reactions between tetanus toxoid and human or rabbit anti-tetanus toxoid IgG antibody, between bovine serum albumin (BSA) and rabbit anti-BSA IgG antibody, and between hen egg albumin and rabbit anti-egg albumin IgG antibody. Ethylene-diaminetetraacetic acid (EDTA) prevented this inhibition. Mg-ethyleneglycol-bis(aminoethyl)-tetra-acetic acid-(EGTA) also prevented the inhibition except with lower concentrations of antibody and antigen. Therefore, the inhibition of immune precipitation seemed to occur mainly through the classical pathway of complement activation. The alternative pathway was usually dispensable, but it augmented the inhibition. Guinea pig complement serum (NGS) was less effective than NHS in inhibiting immune precipitation. Guinea pig serum deficient in C4 (C4DGS) did not inhibit the immune precipitation. Mouse complement serum was effective for inhibiting precipitation, and C5-deficient serum was as effective as normal serum. Therefore, the inhibition of immune precipitation is considered to occur by activation of complement up to the step of C3. The size of the soluble immune complexes formed in the presence of NHS varied depending on the concentrations of antibody and antigen, even when the ratio of antigen to antibody was constant. On incubation at 37 degrees C immune precipitation was inhibited by 1/2 dilution of NHS for 2 to 3 hr and then gradually increased to the level in the absence of complement. When the immune complexes were formed in the presence of serum containing complement, fragments of C4 and C3 were incorporated into the soluble immune complexes. The C3 fragments incorporated into the soluble complexes were C3b, iC3b, C3c, and C3d, some of which were bound covalently with heavy chains of IgG antibody molecules. Some of the covalent linkages between C3 fragments and IgG seemed to be destroyed by alkali treatment, but not by hydroxylamine treatment. The formation of covalent bonds between IgG and C3 and probably C4 was essential for inhibition of immune precipitation, because inhibitors of their formation, such as putrescine, cadaverine, and salicylhydroxamic acid, effectively prevented the inhibition of precipitation. When antigen and antibody reacted in the presence of mixtures of various combinations of isolated complement components, C1, C4, C2, and C3 showed maximal inhibition of immune precipitation, whereas factors I and H had little effect.

Animals↗
PubMedDate not supplied

Attenuation of live E. coli-induced acute lung injury by X-ray irradiation in guinea pigs.

Irradiation is suspected to injure inflammatory cells, such as neutrophils and mononuclear phagocytes, cells known to contribute to the development of acute lung injury (ALI). This study examined whether preexposure to x-ray irradiation modifies ALI induced by E. coli injected intravenously in guinea pig. Thirty animals were divided into two control and two irradiated subgroups: the first control group received saline only (n = 8), and the second control group received E. coli, 2 x 10(9)/kg body weight, suspended in saline (n = 6), IV. The first irradiated group received a single 12-Gy dose + saline (n = 6), and the second irradiated group received a single 12-Gy dose + E. coli (n = 10). The lung wet-to-dry-weight ratio (W/D) and 125I-albumin lung tissue/plasma ratio (T/P) were measured as markers of lung injury. W/D was significantly higher in the control E. coli group than in the other groups. T/P in the control E. coli group was also increased compared with T/P measured in the other groups. In the control E. coli group, a marked increase in bronchoalveolar lavage (BAL) neutrophils was observed compared with the control saline group. However, no significant difference in BAL neutrophil counts was observed between the control and irradiated E. coli groups. In contrast, BAL macrophages were significantly reduced in the irradiated E. coli groups compared with the control E. coli group. These findings suggest that x-ray irradiation attenuates E. coli-induced ALI in guinea pigs, an effect explained, at least in part, by a reduction in the number of alveolar macrophages.

Analysis of Variance↗
PubMedDate not supplied

A congenic line of the DDD mouse strain, DDD/1-Mtv-2/Mtv-2: establishment and mammary tumorigenesis.

A single dominant gene on chromosome 18, Mtv-2, controls both the early appearance of mammary tumors and expression of mouse mammary tumor virus (MMTV) in the milk. A congenic DDD mouse strain, DDD/1-Mtv-2/Mtv-2 (DDD-Mtv-2), was developed by introducing this gene from GRS/AJms (GR) into DDD/1 mice by repeating 12 backcrosses and subsequent inbreeding using mammary tumors as a marker for selection. Southern blot analysis of the liver DNA from the resulting congenic mice with EcoRI and MMTV-U3 prove revealed that two DNA fragments corresponding to Mtv-2 were specifically transferred from GR to congenic mice. Detection of MMTV-gp52 antigen in the mammary gland and mammary tumor development in DDDfDDD-Mtv-2 mice demonstrated the production of infectious mature MMTV by Mtv-2 in congenic mice. About 80% of breeding DDD-Mtv-2 females developed mammary tumors in the course of one-year follow-up. The tumor incidence was lower and the tumor age higher than those in GR mice, suggesting less active functioning of the gene on the DDD genetic background. About 70% of these tumors were morphologically classified as pale cell and type P carcinomas peculiar to GR mice. The gene seemed to control the histologic features of mammary tumors. Congenic mice carried an MMTV provirus in an incomplete form on Y chromosome. The DDD-Mtv-2-strain will provide a new model for biological and molecular researches into mouse mammary tumorigenesis.

Animals↗
PubMedDate not supplied

Differences of milk-transmitted murine mammary tumor virus (MMTV) among mouse strains.

To clarify the oncological differences of milk-transmitted Murine Mammary Tumor Virus (MMTV) in various strains, BALB/c mice were foster-nursed on C3H/He, GR, DDD, DDD/1-Mtv-2/Mtv-2 and FM strains and observed for the development and morphology of mammary tumors, followed by testing tumors for pregnancy dependence (PD) after transplantation. MMTV were different in tumorigenicity and morphology and PD of induced tumors among the mouse strains. These differences of MMTV appeared not to be parallel with the difference in specificity of superantigens which are encoded by MMTV on the previous report. Interestingly, host factors influenced the properties of MMTV produced by the same endogenous Mtv gene.

Animals↗
PubMedDate not supplied

Metallothionein expression in transplantable mouse mammary tumors.

BACKGROUND: The metal binding protein, metallothionein (MT) is involved in various physiological processes. In various human tumors, moreover, MT is reported to play an important role in carcinogenesis. MATERIALS AND METHODS: MT expression was investigated immunohistochemically and chromatographically in a transplantable pregnancy-dependent mouse mammary tumor (TPDMT-4) and related autonomous tumor sublines (T4-OI320 and -OI320CY). RESULTS: All tumor lines showed MT expression in the nucleus and/or cytoplasm of tumor cells. However, adenoacanthomatous T4-OI320 whose structure was different histopathologically from the remaining adenocarcinomas showed over-expression of MT in the basal layer of squamous metaplastic nodules. Cell proliferation activity estimated by the BrdU labeling method (BrdU index) was highest in the squamous nodules and correlated with the degree of MT expression (r = 0.96). By contrast, the BrdU index in T4-OI320CY was inversely correlated with the MT index (r = -0.91). CONCLUSIONS: The present investigation suggests expression of isotype MT in the transplantable mouse mammary tumors which may be involved in the carcinogenesis.

Adenocarcinoma↗
PubMedDate not supplied

Accelerated decline of blood glucose after intravenous glucose injection in a patient with Cowden disease having a heterozygous germline mutation of the PTEN/MMAC1 gene.

The PTEN/MMAC1, a putative tumor suppressor, has been demonstrated to dephosphorylate phosphatidylinositol 3, 4, 5-triphosphate, a key molecule involved in the insulin signaling pathway. The PTEN may act, therefore, as a negative regulator of insulin signaling. The patient with Cowden disease, having a heterozygous PTEN/MMAC1 gene mutation, a C to T substitution of a single base at codon 130, was suspected to have decreased amount of PTEN protein with phosphatase signature motif. We thought that the patient might be more sensitive to insulin than normal subjects. As expected, administration of a bolus of glucose resulted in a more rapid clearance of blood glucose than was observed in 5 control subjects, indicating the presence of insulin hypersensitivity in the patient. The euglycemic hyperinsulinemic clamp study provided additional evidence.

Adult↗
PubMedDate not supplied

Effects of green tea on growth, food utilization and lipid metabolism in mice.

To find whether green tea has anti-obesity effects in mice, female ICR mice were fed on diets containing 1, 2 and 4% green tea powder for 16 weeks and the body weight and food intake were weighed. After the administration of green tea, the ovaries, kidneys, adrenals, liver, spleen, brain, pituitary and intraperitoneal adipose tissues in the mice were weighed and lipid levels in the serum and in the liver and serum leptin levels were measured. It was found that body weight increase and intraperitoneal adipose tissues were remarkably suppressed by the administration of diets containing 2 and 4% green tea powder. Food intake was suppressed by feeding the 4% green tea diet. Concentrations of total cholesterol in the liver, triglycerides in serum and liver and nonestrified fatty acids in serum from mice which were administered green tea diet were lower than those in the controls. Leptin levels in serum showed a decrease with green tea treatments. These results indicated that lipid metabolism in mice was suppressed by the administration of green tea powder and thereby the fatty accumulation and body weight increase was suppressed.

Adipose Tissue↗
PubMedDate not supplied

In vitro fertilization of oocytes from polyovular follicles in mouse ovaries exposed neonatally to diethylstilbestrol.

In 35-day-old female ICR/JCL mice given 5 daily injections of 1 microgram diethylstilbestrol (DES) from the day of birth, a significantly higher incidence of polyovular follicles was found in the ovaries than in those of age-matched control mice. Gap junctions of granulosa cells of mature follicles in neonatally DES-exposed mice were larger than those of the controls. When stimulated by gonadotropins (PMSG and hCG) and caged with males, the number of tubal embryos in DES-exposed mice was less, but the rate of fertilization and development was not different compared to the controls. Division of oocytes collected from the ovaries of 40-day-old DES-exposed and control mice after stimulation of gonadotropins was examined 24 to 72 h after in vitro insemination to ascertain whether fertilization had occurred in oocytes from polyovular follicles. Seventy-seven % of oocytes from uniovular follicles of control mice developed up to 8-cell stage embryos following in vitro insemination; 66% of those from similar follicles of DES-exposed mice developed into the same stage. By contrast, only 47% of oocytes from polyovular follicles of DES-exposed mice showed the division up to 8-cell stage 72 h after insemination, indicating a significantly lower fertilization rate compared to the oocytes from uniovular follicles of control and DES-exposed mice. Without insemination, oocytes taken from the same pools in these experiments never divided during the period of manipulation and incubation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗