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Biomedical subjects

M Imamura

Publications and source records attributed to M Imamura.

At least 757 records · Page 42Linked to original sources
PubMed1980

Variable expression and immunogenicity of an H-2K-coded alloantigen on murine tumours.

The K region of the H-2 major histocompatibility complex (MHC) of mice of H-2Kk haplotype codes for two distinct alloantigens. One of these alloantigens, designated k-common, is expressed by C3HfB/HeN mice (C3Hf). The other alloantigen, designated k-unique, is not expressed by C3Hf mice. The H-2 haplotype of C3Hf mice has been classified as kv1 and the variant antigen distinguishing this strain from mice of H-2Kk haplotype has been designated kv1-unique. Several transplacentally-induced lung tumours of C3Hf mice express the k-unique, rather than the expected kv1-unique, antigen. The immunogenicity of the k-unique antigen on C3Hf-derived lung tumours varies with different tumours. In particular, the capacity of the k-unique antigen to induce radioresistant immunity in C3Hf mice appears to be lost on long term cultured tumour cells even though the tumour remains susceptible to in vivo immune responses directed against the k-unique antigen. Alterations in expression and in immunogenicity of unique H-2-coded antigens may dictate the nature and efficacy of immune surveillance of autochthanous tumours.

Animals↗
PubMed1980

Reactions of potent mutagens, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and 2-amino-6-methyl-dipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1) with nucleic acid.

Two potent mutagens, 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2), isolated from a tryptophan pyrolysate, and 2-amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole (Glu-P-1), isolated from a glutamic acid pyrolysate, modified calf thymus DNA in the presence of rat liver microsomes. The major base modified by Trp-P-2 was identified wih 3-(3-guanyl)amino-1-methyl-5H-pyrido[4,3-b]indole. The major base modified by Glu-P-1 was identified with 2-(8-guanyl)amino-6-methyldipyrido[1,2-a:3',2'-d]imidazole. N-acetoxy-Glu-P-1 efficiently modified DNA without microsomes.

Animals↗
PubMed1979

Lung tumor-reactive cytotoxic lymphocytes generated in mixed lymphocyte reaction between C3HfeB/HeN (H-2kb) and C3H/HeN (H-2k) strain mice.

The tumor-associated transplantation antigen expressed by several transplacentally induced lung tumors of C3HfeB/HeN mice (H-2kb haplotype) has previously been shown to exist as a normal tissue alloantigen in mice of known H-2k and H-2a haplotypes. This antigen is not expressed in normal tissues of C3HfeB/HeN mice but is expressed in C3H/HeN mice, the strain from which the C3HfeB/HeN mice were originally derived. The present study indicates that spleen cells from C3HfeB/HeN and C3H/HeN mice respond reciprocally in the mixed lymphocyte reaction. Cytotoxic T lymphocytes specific for the tumor-associated alloantigen can be readily generated in mixed lymphocyte reactions in which spleen cells from C3HfeB/HeN mice are reacted with x-irradiated spleen cells from C3H/HeN or A strain mice. These cells are effective in suppressing the growth of the C3HfeB/HeN-derived lung tumor 85 in x-irradiated syngeneic recipients.

Animals↗
PubMed1979

Surgical importance of oblique projection in arteriography for carcinoma of the pancreas.

Oblique projections in celiac and superior mesenteric angiography have been of value in patients with carcinoma arising in various parts of the pancreas. Oblique views allow better perception of the slight and uncertain changes in the pancreatic vessels, which are not discernible on anteroposterior projections because of overlapping with the extrapancreatic vessels and the spine. Anteroposterior and oblique views of both celiac and superior mesenteric arteries are the first, and, therefore, the most essential, step in angiography of lesions of the pancreas.

Angiography↗
PubMed1979

Correlative evaluation of angiography and pancreatoductography in relation to surgery for cancer of the pancreas.

The results of preoperative angiograms and pancreatoductograms in 37 patients with cancer of the pancreas were correlated with each other, with the findings at laparotomy, and with survival times. Tumors which could not be detected by arteriography and/or pancreatography were resectable, except for those located in the uncinate process. Among the resectable tumors, those which were identified only by pancreatography were confined mostly to the parenchyma of the pancreas and were nearly 2 cm in size. Those patients were expected to have a long survival after total pancreatectomy. In contrast, those tumors which were diagnosed only by arteriography arose from the subcapsular portion of the gland or the uncinate process and showed macroscopic invasion to the capsule of the pancreas. These tumors, recurred within 1 year, despite total pancreatectomy. The resectable tumors showing both vascular and ductal invasion were more than 3 cm in size and extended far beyond the capsule of the gland, and patients with these tumors died within 1 year after operation. In this group no difference in survival time was seen among those treated by the Whipple procedure, those by total pancreatectomy, or those by resection of the total pancreas and the portal vein.

Adult↗
PubMed1978

Lung tumor-associated derepressed alloantigen coded for by the K region of the H-2 major histocompatibility complex.

Transplacental induction of lung tumors in C3HfeB/HeN (C3Hf) strain mice can be readily achieved with the carcinogen 1-ethyl-1-nitrosourea. Several of these tumors express, as a tumor-associated transplantation antigen (TATA), a normal tissue alloantigen present in strain A and C3H/HeN (C3H) mice. In the present study it was shown that the tumor-associated alloantigen on the C3Hf-derived lung tumor 85 was present in all mice of H-2(a) and H-2(k) haplotypes tested and in CBA (532) strain mice (H-2(ka) haplotype). Studies using congenic-resistant and recombinant strains of mice indicated that the genetic locus controlling the expression of this antigen was either within or to the left of the H-2K region of the major histocompatibility complex (MHC). Thus the antigen was expressed in B10.A (4R) mice (kkbbbb MHC haplotype) but not in B10 (bbbbbb) or B10.AQR mice (qkkddd). The antigen was expressed in all tissues tested of C3H and A strain mice. It was not detected on any tissue tested including embryo tissue of C3Hf mice or mice of MHC haplotype other than H-2(k) or H-2(a). Because C3Hf strain mice were originally derived from C3H strain mice (H-2(k)), the MHC haplotype of C3Hf mice has been provisionally designated H-2(kb). The finding of a tumor-associated change in the expression of a H-2K region-coded antigen is consistent with the concept that MHC-coded antigens may act as targets for immunological surveillance of tumors.

Animals↗
PubMed1977

Anti-tumour immunity by normal allogeneic blood transfusion in rat.

Growth of transplantable KMT-17 tumour in syngeneic WKA/MK rats was inhibited by i.v. preimmunization with whole blood from normal rats of allogeneic strains. The inhibitory effect was also observed in rats immunized with allogeneic white blood cells alone. The strength of the inhibitory effect mainly depended on the the strain of donor rat used; blood from Donryu and Kyoto strain rats produced the strongest inhibition, blood from Tokyo and Fischer strain rats produced moderate inhibition to the syngeneic tumour growth. Blood from ACI/N strain rats did not produce the inhibition. The mechanism of blood transfusion in inhibiting tumour growth is not yet clear. However, it seems that GVH reaction does not play an important role in the mechanism of the inhibition effect, because the effect was obtained by immunization with mitomycin C-treated allogeneic white blood cells and also by the immunization effect may be due to nonspecific active immunization. Significance of blood transfusion with special reference to clinical immunogtherapy of cancer is discussed.

Animals↗