Biomedical subjects

M Hirota

Publications and source records attributed to M Hirota.

At least 271 records · Page 15Linked to original sources

PubMed1984

A monoclonal antibody, CSTO-1, against a stomach adenocarcinoma-associated antigen.

A monoclonal antibody, CSTO-1, has been produced against a stomach adenocarcinoma-associated antigen. The antibody is cytotoxic to stomach, colon, and lung adenocarcinoma lines but is completely noncytotoxic to normal blood elements and leukemic cell lines. The monoclonal antibody reacts with tumor cell membranes in enzyme-linked immunosorbent assay and is negative to cell membranes from various normal tissues. By immunoperoxidase testing, the antibody reacts with 18 of 22 stomach adenocarcinomas, 11 of 16 colon adenocarcinomas, 3 of 4 squamous cell carcinomas of the lung, and 1 of 4 lung adenocarcinomas. In addition, the antibody reacts with the superficial epithelium of normal tissues such as colon, stomach, esophagus, acinar cells and duct epithelium of the pancreas, bronchial epithelium of the lung, and sweat duct epithelium of the skin. Thus, the CSTO-1 antibody reacts to an antigen present in normal superficial epithelia, as well as on various tumors. It is of potential use in detecting these antigens on tumor sections and eventually may be used in immunotherapy.

Adenocarcinoma↗

PubMed1983

Salivary gland glucagon is a fictitious substance due to tracer-degrading activity resistant to protease inhibitors.

A high level of glucagon immunoreactivity was apparently detected in acid-saline extract from rat submandibular glands, but tracer glucagon added to the assay mixture was mostly damaged in spite of the presence of protease inhibitors commonly used in radioimmunoassay. Gel-filtration of the extract on a Bio-Gel P-10 column revealed strong tracer-degrading activity at the void fraction where the apparent immunoreactivity was eluted. Serial changes in apparent immunoreactivity of the extract fit well on the theoretical curve of an exponential tracer degradation. These findings indicate that the salivary gland glucagon is a fictitious substance due to tracer degradation during radioimmunoassay. Further study revealed that the glucagon molecule was hydrolyzed at the arginyl bonds and split into two fragments during incubation with the acid-saline extract from rat submandibular glands.

Animals↗

PubMed1983

Epstein-Barr virus activation by tung oil, extracts of Aleurites fordii and its diterpene ester 12-O-hexadecanoyl-16-hydroxyphorbol-13-acetate.

During the screening of plant oils for their Epstein-Barr virus (EBV)-activating potency, we found that tung oil possesses an activity comparable to croton oil. Tung oil from various sources and the extracts from its parental plant Aleurites fordii (Chinese tung oil tree), when used in combination with n-butyrate, were shown to efficiently activate EBV persisting in human lymphoblastoid Raji cells (non-producer). The major diterpene ester in the plant extract, 12-O-hexadecanoyl-16-hydroxyphorbol-13-acetate (HHPA), also exerted a similar activity. In producer P3HR-1 cells, both tung oil and HHPA increased the yield of infectious EBV by approximately five-fold. Since tung oil is used for the manufacture of oil paints, varnishes, waterproof substance, anticorrosives and other products, the implication of using such an agent with EBV-activating potency in our daily life is assessed and discussed.

Cells, Cultured↗

PubMed1983

Effect of membrane fluidizers on the number and affinity of chemotactic factor receptors on human polymorphonuclear leukocytes.

Chemotaxis by leukocytes appears to be initiated by the binding of chemo-attractants to specific cell surface receptors. In other biological systems, the affinity and functional activity of membrane receptors are regulated by the local microviscosity. The present studies were undertaken to determine if the number and/or affinity of chemotactic factor receptors expressed on human polymorphonuclear leukocytes were similarly affected. Aliphatic alcohols and cis-vaccenic acid, agents known to decrease membrane microviscosity, were studied for their effects on the binding of the radiolabeled chemoattractant f-Met-Leu-[3H]Phe to human polymorphonuclear leukocytes. Butanol and propanol increased the number of f-Met-Leu-[3H]Phe binding sites approximately 1.5 fold. More dramatically, these same agents enhanced the affinity of the receptor by ten-fold, without affecting the specificity of the receptor. Similarly, cis-vaccenic acid enhanced both the number and affinity of this chemotactic factor receptor on human polymorphonuclear leukocytes contain cryptic receptors for the N-formylated peptide chemotactic factors, but more importantly that the affinity of these receptors can exist in more than one state and can be modulated by membrane microviscosity. Alterations of membrane fluidity in leukocytes during chemotaxis may be an important mechanism for regulating their sensitivity to chemoattractants.

Alcohols↗

PubMed1983