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Biomedical subjects

N Endo

Publications and source records attributed to N Endo.

At least 145 records · Page 8Linked to original sources
PubMed1988

In vitro and in vivo augmentation by muroctasin of the production of the third component of complement by murine macrophages.

In vitro and in vivo examinations were carried out to assess the influence of N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys (L18), muroctasin) on the biosynthesis of the 3rd component of complement (C3) of murine peritoneal macrophages. The amount of C3 in the supernatant of the macrophages cultured in serum free minimal essential medium (MEM) was measured using the enzyme-linked immunosorbent assay (ELISA) system. The in vitro C3-production by the cultured macrophages was inhibited by treatment with cycloheximide, but promoted dose-relatedly with MDP-Lys (L18). The in vitro ability of peritoneal macrophages derived from mice treated subcutaneously with MDP-Lys (L18) to produce C3 was also augmented significantly: a diphase pattern of production was noticed during the 120 h following administration. According to the immunoelectrophoretic analysis, C3 thus produced by cultured peritoneal macrophages was identical with the native C3 in serum.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1988

Stimulation of plasma fibronectin production in mice by muroctasin.

The production of plasma fibronectin (PFN) in mice treated subcutaneously with N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-lysine (MDP-Lys(L18), muroctasin), was examined. The plasma levels of PFN in mice increased significantly by treatment with a single dose of 10 to 100 micrograms/mouse of MDP-Lys(L18). A slight strain difference in the PFN levels among Std: ddY, C3H/He, and DBA 2 mice was observed: the percent increases at the maximal level in Std: ddY, C3H/He, and DBA/2 mice were 21.6, 19.9, and 10.4, respectively. In Std: ddY mice, the concentration of PFN reached the maximal level at 15 h post-treatment, and decreased gradually of the normal level by 48 h. These results indicate that MDP-Lys(L18) stimulates the PFN production in mice.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1987

A novel covalent modification of antibodies at their amino groups with retention of antigen-binding activity.

A novel method of covalent modification of antibodies at their amino groups with retention of antigen-binding activity is described. The procedure is as follows: (a) blockade of those amino groups of antibodies whose integrity is essential to their antigen-binding activity with 2,3-dimethylmaleic anhydride, a reversible amino group-blocking reagent; (b) modification of residual amino groups with reagents reactive with the amino groups; and (c) removal of dimethylmaleyl groups by hydrolysis. This procedure was used for covalent conjugation of methotrexate (MTX) with two monoclonal antibodies against human melanoma-associated antigens using MTX N-succinimidyl ester. MTX attached to the antibodies at sites other than the amino groups via less stable bond(s) was removed by treatment with hydroxylamine.

Amines↗
PubMed1987

Enhanced responsiveness to parathyroid hormone and induction of functional differentiation of cultured rabbit costal chondrocytes by a pulsed electromagnetic field.

Pulsed electromagnetic fields promote healing of delayed united and ununited fractures by triggering a series of events in fibrocartilage. We examined the effects of a pulsed electromagnetic field (recurrent bursts, 15.4 Hz, of shorter pulses of an average of 2 gauss) on rabbit costal chondrocytes in culture. A pulsed electromagnetic field slightly reduced the intracellular cyclic adenosine 3',5'-monophosphate (cAMP) level in the culture. However, it significantly enhanced cAMP accumulation in response to parathyroid hormone (PTH) to 140% of that induced by PTH in its absence, while it did not affect cAMP accumulation in response to prostaglandin E1 or prostaglandin I2. The effect on cAMP accumulation in response to PTH became evident after exposure of the cultures to the pulsed electromagnetic field for 48 h, and was dependent upon the field strength. cAMP accumulation in response to PTH is followed by induction of ornithine decarboxylase, a good marker of differentiated chondrocytes, after PTH treatment for 4 h. Consistent with the enhanced cAMP accumulation, ornithine decarboxylase activity induced by PTH was also increased by the pulsed electromagnetic field to 170% of that in cells not exposed to a pulsed electromagnetic field. Furthermore, stimulation of glycosaminoglycan synthesis, a differentiated phenotype, in response to PTH was significantly enhanced by a pulsed electromagnetic field. Thus, a pulsed electromagnetic field enhanced a series of events in rabbit costal chondrocytes in response to PTH. These findings show that exposure of chondrocytes to a pulsed electromagnetic field resulted in functional differentiation of the cells.

Alprostadil↗
PubMed1987

The molecular abnormality of albumin Niigata: 269 Asp----Gly.

A slow albumin variant was isolated from the serum of a patient with bisalbuminemia. Reverse-phase peptide mapping revealed a single altered peak when tryptic digests of the normal and variant albumin were compared. After rechromatography and amino acid analysis, a sequence of Tyr-Ile-Cys-Glu-Asn-Gln-Gly-Ser was obtained for the mutant peptide, while a sequence of Tyr-Ile-Cys-Glu-Asn-Gln-Asp-Ser was obtained for the normal peptide. This establishes the mutation as 269 Asp----Gly and the new albumin has been named albumin Niigata.

Adult↗
PubMed1987

In vitro cytotoxicity of a human serum albumin-mediated conjugate of methotrexate with anti-MM46 monoclonal antibody.

In studies on antitumor antibody:drug conjugates as potential antitumor agents, methotrexate (MTX) was conjugated with a murine monoclonal antibody (aMM46) to an antigen on ascitic mouse mammary tumor MM46 cells (MM antigen) with human serum albumin (HSA) as an intermediary. MTX was linked to HSA which had been conditioned to have about 1 mol of thiol group per mol of HSA by dithiothreitol treatment followed by oxidation on standing at 4 degrees C. The MTX linking was performed, without protection of the thiol group of HSA, by using MTX N-succinimidyl ester prepared via MTX intramolecular anhydride. The resulting HSA:MTX was reacted with the immunoglobulin with the maleimide group introduced. The aMM46:HSA:MTX obtained retained both antibody binding and drug activities. The cytotoxicity of aMM46:HSA:MTX against MM antigen-positive MM46 cells was greater than that of control 96.5 (anti-human melanoma-associated antigen, p97):HSA:MTX and was inhibited by unconjugated aMM46. No different cytotoxicity of aMM46:HSA:MTX compared with that of 96.5:HSA:MTX was observed against MM antigen-negative mouse mammary tumor MM48 cells. The presence of ammonium chloride or leupeptin abrogated the selective cytotoxicity against MM46 cells of aMM46 conjugate but did not affect the nonspecific cytotoxicity of 96.5:HSA:MTX. These results support the idea that the selective cytotoxicity of aMM46:HSA:MTX is antibody directed and exhibited through lysosomal degradation of the conjugate.

Ammonium Chloride↗
PubMed1987

Target-selective cytotoxicity of methotrexate conjugated with monoclonal anti-MM46 antibody.

In studies on antitumor antibody-cytotoxic drug conjugates as potential tumor-selective cytotoxic agents, methotrexate (MTX) was conjugated via its active ester derivative with a murine monoclonal antibody (aMM46) to a mouse mammary tumor antigen (MM antigen) on syngeneic, ascitic C3H/He mouse mammary tumor MM46 cells. The conjugate retained full antibody activity, as assayed by complement-dependent cytolysis. The target-selective cytotoxicity of aMM46-MTX was verified by the observations that this conjugate showed greater cytotoxicity than the corresponding normal mouse immunoglobulin (nIg) conjugate to MM46 cells, neither aMM46 nor nIg being cytotoxic, and that it showed less cytotoxicity to MM antigen negative mouse mammary tumor MM48 cells than to MM46 cells, its cytotoxicity to MM48 cells being similar to that of the nIg conjugate. From the results of assays of cell binding and uptake of 131I-labeled aMM46 and aMM46-3H-MTX, aMM46 and aMM46-MTX were internalized after their binding to MM46 cell surface antigen. Leupeptin, an inhibitor of the lysosomal endopeptidase cathepsin, decreased the cytotoxicity of aMM46-MTX, supporting the involvement of lysosomal degradation of the conjugate in its action.

Animals↗