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Biomedical subjects

N Ishida

Publications and source records attributed to N Ishida.

At least 469 records · Page 26Linked to original sources
PubMed1980

Demonstration of IgG EA (early antigen) and IgM MA (membrane antigen) antibodies in CMV infection of healthy infants and in those with liver disease.

The sequence of antibody production to various virus-specific antigens in CMV infection in infancy was studied. In healthy infants, IgG EA antibody was demonstrated in 18% of cord sera, and disappeared within two months after birth in all cases not shedding virus. The nonmaternal EA antibody was produced following virus excretion and decreased rapidly following cessation of virus excretion. Thus, demonstration of EA antibody in infants after 2 months of age was found to indicate acquired CMV infection, even when CMV could not be isolated. IgM MA antibody did not persist as long as EA antibody, disappearing before cessation of virus excretion. Both IgG EA and IgM MA antibodies were more frequently demonstrated in infants with hepatitis than in healthy infants. These findings suggest the possible association of CMV with hepatitis in infants.

Antibodies, Viral↗
PubMed1980

Immunosuppressive factors from mastocytoma cells cultured in serum-free medium.

Immunosuppressive factors were isolated from culture fluids of DBA/2 mouse mastocytoma cells grown in serum-free RPMI-1640 medium by measurement of inhibitory activity on tritiated thymidine uptake of DBA/2 spleen cells responding to Escherichia coli lipopolisaccharide (LPS) and concanavalin A (ConA) and by comparison of the number of hemolytic antibody-forming cells in vitro after simultaneous addition of the factors with sheep red blood cells (SRBC). The culture fluids were separated into four fractions with immunosuppressive activities: F-I (mol wt, > 30,000), and F-II (mol. wt, 10,000-30,000), F-III (mol wt, 2,000-10,000), and F-IV (molwt, 700-2,000), F-IV specifically suppressed lymphocyte responses to E. coli LPS at concentrations of 50-200 microgram/ml. The other three fractions also showed immunosuppressive activities in both Con-A-induced and E. coli LPS-induced lymphocyte responses. The four fractions as well as crude culture fluids of mastocytoma cells expressed as immunosuppressive effect when injected into the peritoneal cavities of DBA/2 mice at doses of 24-180 microgram/day for 5 consecutive days. The fractions with a molecular weight equivalent to F-IV of mastocytoma culture supernatant were detected little, if any, in the supernatant from a nonmalignant cell culture. No suppressive effects of the fraction with a molecular weight greater than 2,000 (equivalent to F-I + F-II + F-III) from nonmalignant cell culture were found on lymphocyte responses to mitogens or SRBC at the concentrations used (100-200 microgram/ml).

Animals↗
PubMed1980

Mouse spleen cell nuclear protein kinases and the stimulating effect of dsDNA on NHP phosphorylation by cyclic AMP-independent protein kinase in vitro.

cAMP-dependent (designated as enzyme I, about 68,000 daltons) and cAMP-independent protein kinase (designated as enzyme II, about 45,000 daltons) have been partially purified from the nuclei of mouse spleen cells. Both kinases phosphorylated calf thymus histones as well as non-histone proteins (NHP) and required Mg2+ (8 mM) or Mn2+ (2 mM) for maximal activity. NEM (0.5 mM), which is an inhibitor of SH-enzymes, inhibited the histone phosphorylating activity of enzyme II by more than 90%, whereas it inhibited the activity of enzyme I by less than 10%. Moreover, the activity of enzyme II was more sensitive to high temperature than that of enzyme I. Non-histone protein (CM-III protein) served as a more effective substrate for enzyme II than histones; the Km value for CM-III protein was 34.4 micrograms/ml whereas that for histone H2a (14,300 daltons) was 155 micrograms/ml (1.08 x 10(-5) M). CM-III protein phosphorylation by enzyme II in vitro was greatly stimulated by the addition of dsDNA, but not by single-stranded DNA or bacterial ribosomal RNA. However, the phosphorylation of CM-III protein by enzyme I was less than 50% of that of histones, and there was no stimulatory effect. SDS-gel electrophoresis showed that two distinct NHPs (about 13,000 and 19,000 daltons) prepared from calf thymus chromatin were preferentially phosphorylated by enzyme II in vitro in the presence of dsDNA. This finding suggests that these two NHPs may be specific phosphate acceptors of cAMP-independent protein kinase (enzyme II) in the nuclei of mouse spleen cells.

Animals↗
PubMed1980

Glycopeptide composition of hepatitis B surface antigen.

Three major polypeptides of hepatitis B surface antigen (HBsAg), with mol. wt. 22,000 (p22), 27,000 (p27) and 68,000 (p68), were separated by preparative SDS-PAGE. These three peptides as well as intact HBsAg were found to have almost identical amino acid compositions and carbohydrate was detected in p27 and p68 by PAS staining. Papain treatment of p68 produced two distinct peptides p27 and p22. Moreover, when an artificial mixture of p27 and p22 in a ratio of 1:1 was treated with 0.2 M-periodate for 30 min at 37 degrees C, only p22 was detectable. These results suggest that p68 is composed of p27 and p22, and that p27 is a glycosylated product of p22. Thus, from the evidence obtained, it is possible that p22 (22,000 peptide) is the minimum size of the unique hepatitis B virus (HBV) gene product involved.

Amino Acids↗
PubMed1980

Antigenic conversion from HBcAg to HBeAg by degradation of hepatitis B core particles.

Highly purified and homogenous hepatitis B core particles were obtained from an autopsy liver. The core particles consisted mainly of an electrophoretically single major polypeptide with a molecular weight of 20,000 daltons. When antigenic conversion from hepatitis B core antigen (HBcAg) to hepatitis B e antigen was achieved by treating these core particles by sonication or by passing them through an anti-HBc IgG-conjugated Sepharose 4B column, no appreciable changes were found in the above protein composition. The same antigenic conversion was also achieved by centrifugation of core particles in CsCl, which revealed the process of morphological disintegration accompanied by antigenic conversion. These observations may support the hypothesis that HBcAg resides on a protein conformation which consists of a polypeptide sharing HBe antigenicity.

Chromatography, Affinity↗
PubMed1980

Selective inhibition of nucleoside transport into mouse lymphoma L-5178Y cells by cimicfugoside.

Cimicifugoside, a triterpenoid from Cimicifuga simplex, is a potent inhibitor of thymidine-3H uptake by Raji cells, L-cells cl 1D cells, HeLa S3 cells and L-5178Y cells without affecting the growth rate of any cell type tested. It has also inhibited the uptake of purine and pyrimidine ribosides and deoxyribosides of adenosine, inosine, uridine and nucleoside analogs in L-5178Y cells. It did not inhibit phosphorylation of thymidine or adenosine, or the transport of nucleic acid bases, sugars, amino acids and arabinosyl analogs of nucleosides. The results suggest that cimicifugoside is a potent and selective inhibitor of nucleoside transport at the plasma membrane site of mammalian cells.

Animals↗
PubMed1980

The immune response of splenic lymphocytes after cimicifugoside treatment in vitro and pretreatment in vivo.

Pretreatment of mouse splenocytes with Shigella lipopolysaccharide and concanavalin A followed by 50 ng/ml of cimicifugoside resulted in a 69% and 31% inhibition of blastogenesis compared to controls. The plaque forming colony assay using sheep erythrocytes (SRBC) showed a decreased number of plaque forming colonies after exposure of the splenic cells to 1 microgram/ml of cimicifugoside. Cimicifugoside, 0.1 mg/mouse i.p. suppressed the anti-SRBC response in the plaque forming assay. The major inhibition of the antibody response occurred when cimicifugoside was administered 1 day before the primary immunization with SRBC. The delayed type hypersensitivity to picryl chloride was suppressed after i.v. administration of cimicifugoside, 1.0-2.0 mg/mouse. The immunosuppressive activity of cimicifugoside is preferentially directed toward B-cell function with larger doses being required for suppression of T-cell function.

Animals↗
PubMed1980

The promoting effect of amphotericin B on the incorporation of neocarzinostatin into human gastric cancer tissue.

AmB/NCS combination therapy against cancer was evaluated. Six gastric cancer patients were treated in this manner, and 7 gastric cancer patients treated with NCS alone to serve as the control. AmB sirup was administered orally for 4 days before surgical operation. NCS was given intraveously at the onset of gastric surgery. Lesion tissues and healthy tissues were collected from each patient and the NCS titers were measured by bioassay. It was shown in the majority of the gastric cancer cases that the NCS levels in the lesion tissues were substantially higher than in the surrounding normal tissues, whereas in the gastric cancer patients who received NCS alone, no significant differences were found between the tissues.

Adult↗
PubMed1980

Transfer factor from BCG-sensitized mice.

A mouse model was established for the study of transfer factor (TF). TF was extracted from the spleens of sensitized mice and examined for activity by the footpad test, which showed that mouse and human TF possessed similar properties. Parenteral administration of TF imparted to unsensitized mice immunologically specific, delayed type hypersensitivity within 24 hr. The magnitude of the response the recipients was proportional to the dose of TF. TF activity was relatively heat-stable, detectable in a fraction of molecular weight of ca 1,000 and apparently contained nucleic acids. Nude mice responded negatively to TF but following administration of viable naive spleen cells a positive response was observed, which suggests that the thymus plays an important role in the expression of TF phenomenon and that the target of TF is the T cells.

Animals↗
PubMed1980

Morphological and functional studies of human fetal liver cells in primary monolayer culture.

Livers from human fetuses between the 16th and 24th weeks of gestation were dissociated by successive dispase and collagenase digestion followed by two cycles of low-speed differential centrifugation. This improved method recovered approximately 1 X 10(7) cells (90% hepatocytes and 90% viable cells) from 4 g of liver tissue. These hepatocytes were set into primary culture and monolayer granular hepatocytes were obtained within a week. Both albumin and alpha-fetoprotein production was demonstrated in these granular hepatocytes by the immunoperoxidase method for 2 weeks and alpha-fetoprotein production in the culture medium occurred for a week by the single radial immunodiffusion method. The morphological features of the granular hepatocytes could be distinguished from those of the other type of epithelial cells with clear cytoplasm. During the cultivation period, gradual changes from granular to clear hepatocytes with high mitotic activity were found.

Albumins↗
PubMed1980

The biological effect of a nonprotein component removed from neocarzinostatin (NCS).

The biological effects of both nonprotein component (NPC) and PC (protein component) from NCS have been studied in vivo and in vitro. NPC was found to not only inhibit DNA synthesis in growing cells but also induce DNA degradation in vivo and in vitro. However, neither these two biological activities of PC were detected even at a 100-times higher concentration of NPC (0.2 micrograms/ml) which inhibited 50% DNA synthesis in growing cells. NPC-induced DNA degradation in vitro was stimulated by 2-mercaptoethanol as has been reported for NCS. These results show that the NPC removed from NCS is responsible for the biological activities such as the inhibition of DNA synthesis in growing cells and the induction of DNA degradation in vivo and in vitro.

Antibiotics, Antineoplastic↗