Biomedical subjects
Publications and source records attributed to M Kotani.
The study of biomagnetic fields originating in a biological body is called biomagnetism. Among various fields of biomagnetism, this paper reviews the research and clinical works in magnetocardiogram, neuromagnetism, magneto-oculogram, magnetopneumogram and magnetic measurement for cell motility carried out in Japan.
A single intraperitoneal injection with a 10 mg estriol (E3) in aqueous suspension induced a large and prolonged elevation of serum alpha-fetoprotein (AFP) in adult mice. E3 also raised the mitotic activity of hepatocytes in the absence of liver injury. Although both the AFP concentration and hepatocyte proliferation reached the peak on day 5 after E3 administration, a high level (about 12,500 ng/ml) of serum AFP persisted for a long period after hepatocyte proliferation declined. Five mg E3 showed a remarkable threshold effect on AFP elevation and 3 mg E3 on hepatocyte proliferation. Immunohistochemical studies indicated AFP production by hepatocytes in adult mice after the E3 administration.
The splenic macrophages of rats and mice were studied by light and fluorescence microscopy to determine their phagocytotic uptake of carbon and neutral polysaccharide (Fic-F), and their lysosomal enzyme activities. In rats, the large macrophages of the marginal zone (MZ) showed a moderate to strong acid phosphatase activity, and took up most of the Fic-F, even though they showed a weak phagocytotic activity to carbon particles. Red-pulp macrophages, however, ingested a large quantity of carbon particles, and are considered to be the major scavengers in the rat spleen. In contrast, the MZ macrophages in the mouse spleen were the major scavengers and showed a vigorous uptake of both carbon and Fic-F. In rats, the marginal metallophils (MM), located at the outer border of the periarterial lymphatic sheath and boundary between the MZ bridging channel and surrounding tissue, ingested Fic-F, whereas those located around the follicular area did not. In mice, on the other hand, the MM never ingested Fic-F. Lightly carbon-ladened small cells were constantly seen in the MZ of both rats and mice. They showed little acid phosphatase activity and did not ingest Fic-F. They were also present in the blood circulation.
A single oral administration of a pharmacological dose of estriol (E3) immediately after transplantation of small liver fragments of mice under the kidney capsule induced a remarkable growth of regenerating liver tissue. The hepatocytes were successfully arranged in cords with well developed sinusoids between them. The cytoplasm of the hepatocytes showed prominent basophilia. In mice injected with carbon intravenously, large numbers of carbon-laden endothelial lining cells and Kupffer cells appeared in the newly building sinusoids. E3 raised the mitotic activity of the regenerating hepatocytes markedly and for a long period. The act of E3 on mitosis was much more effective on the regenerating hepatocytes than on the recipient's own hepatocytes.
The spleen of (PvG/c X DA)F1 rats, intravenously injected with carbon, was investigated. Large heavily carbon-laden (LHC) macrophages, which were found only in the red pulp at 30 min, appeared along marginal zone bridging channels (MZBC) from the red pulp towards the white pulp side successively during 1-6 h after carbon injection. After this time, they appeared in the periarterial lymphatic sheaths (PALS) near MZBC and then in the deeper PALS along the arteries by 5-10 days. Frequently, they were found in rows from MZBC into the white pulp. These findings suggest migration of LHC macrophages from the red towards the white pulp trough MZBC. Possible migration of LHC macrophages through MZBC was observed for a long period--at least 3 months examined. LHC macrophages came together preferentially in PALS and in and around the germinal centers consisting of large pyroninophilic lymphoblastoid cells. Occasionally, possible migration of LHC macrophages from regions around sinuses crossing the marginal zone vertically (vertical sinus) was also observed. Sinuses accompanied by LHC macrophages often ran parallel in close association with MZBC, particularly at sites of MZBC near the red pulp.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The induction of unresponsiveness to mycobacterial adjuvant took a longer time in male DA rats than in female rats. A shift in the induction time of unresponsiveness in males toward the female type was brought about by castration, but could be reverted to the male type by the application of testosterone. The transfer study revealed that cells capable of preventing arthritis required a longer incubation time for their development in males than in females. This suggests that testosterone inhibits the development of suppressor cells in adjuvant arthritis.
Diazepam (10(-5)-3 X 10(-4) M) selectively enhanced the negative inotropic responses of guinea-pig atria and the relaxation of guinea-pig taenia coli caused by adenosine and ATP. In the atria, the effect of 2-chloroadenosine, a stable analog of adenosine, was not affected by diazepam. Segments of guinea-pig atria or taenia coli took up 3H-activity during incubation with [3H]adenosine but did not take up 32P-activity from [32P]ATP. Diazepam at concentrations sufficient to enhance the in vitro responses reduced by half the uptake of 3H-activity into the preparations. Adenosine (10(-6) M) and ATP (10(-6) M) were degraded to inactive inosine during incubation with atrial segments and their degradation was inhibited by diazepam. In contrast, in rat atria, diazepam did not enhance the negative inotropic effects of adenosine and ATP, and did not prevent the uptake of adenosine. These results suggest that in guinea-pig atria and taenia coli, diazepam like dipyridamole, acts as an adenosine potentiator by preventing the uptake and degradation of adenosine.
Histological observations of the mouse spleen were carried out at different times after intravenous carbon injection. Large carbon-laden macrophages appeared in great numbers in the marginal zone soon after injection. They came together favorably around the germinal centers. Possible migration of these cells toward the germinal centers diffusely from the periphery of the white pulp or through the periarterial lymphoid sheath was suggested. These macrophages entered the germinal centers on a large scale and clustered for a long period--at least 180 days. Since the same type of macrophages were observed persistently in the marginal zone, it was thought that some of them might arise from the blood stream. Possible migration of these cells from the marginal zone toward the germinal centers was also persistently observed. A second type of much smaller carbon-laden macrophages was seen in the white pulp. However, they never showed any favorable localization in the germinal centers as did large carbon-laden macrophages.
In the first experiment, histological observation of the mouse spleen was carried out after intravenous carbon injection. Large carbon-laden macrophages were found in the marginal zone soon after injection and then they appeared to migrate into the white or red pulp. Macrophages migrating deeply into the white pulp came together favorably around the germinal centre and entered the majority of the germinal centres by 10 days. In the second and third experiments, syngeneic transfer of rat peritoneal macrophages labeled with carbon were performed. They were injected either retrograde via hepatic artery or directly into the splenic artery. Carbon-laden macrophages were found in the germinal centres in the spleen 12 to 24 hours after injection though in a limited number. Possible migration of intrinsic as well as extrinsic macrophage from the marginal zone into the germinal centre was demonstrated.
The bursa of Fabricius was isolated from gut-derived antigens by ligating the bursal duct on the 18th day of incubation. Ligation of the bursal duct (BDL) suppressed the bursal development, spontaneous germinal centre formation in the spleen and the development of serum "natural" agglutinins for bacteria or heteroerythrocytes. Moreover, administration of sterilized cecal contents into the bursal lumen at BDL led to normal level of serum "natural" agglutinins. These findings strongly suggest that the bursa of Fabricius possesses an antigen-dependent process which modulates the development of immune system. Antigen-trapping mechanism of the bursa may supply information about environmental antigens for this process.
The susceptibility of congenitally anemic, and mast cell deficient W/Wv mice to infection with Strongyloides ratti was examined. After a primary infection, W/Wv mice showed greater and more persistent peak larval counts than did normal littermates. Worm expulsion was also slower in W/Wv mice than in +/+ mice. Furthermore, difference in susceptibility was expressed as early as 24 h after infection, suggesting not only that protective mechanisms of the gut but also of the connective tissue were defective in W/Wv mice. Reconstitution with bone marrow or spleen cells from +/+ mice was effective in restoring the protective response in W/Wv mice, whereas thymocytes or mesenteric lymph nodes had no effect. Both connective tissue and mucosal mast cells were repaired in W/Wv mice after marrow reconstitution and infection. Since relatively long incubation period was required for the expression of such reconstituting activities, bone marrow cells seem to contain precursor cells of the effector and/or regulator cells.
A single oral administration of natural principal estrogens, estrone (E1), 17 beta-estradiol (E2) and estriol (E3), caused active proliferation of hepatocytes of adult mouse liver. Steroid hormones tested (testosterone, progesterone and cortisone) other than estrogens were not stimulants of proliferation of hepatocytes. Among these three natural estrogens, E3 was found to be the most potent stimulant of hepatocyte proliferation and E1 was the weakest. The possible mechanism of the hepatocyte-proliferating potency of estrogens was discussed in close relationship to their stimulating effect on the reticuloendothelial system.
Explore the source record for details and available documents.
Granulocyte-macrophage colony-stimulating activity (GM-CSA) in mouse serum was examined after a single intraperitoneal injection with 10 mg estriol (E3). GM-CSA was detectable as early as 6 h after E3 administration and reached a peak by 24 h. Elevation of GM-CSA in the serum was maintained for at least 30 days. Using 0.1-10 mg of E3 there was a dose-dependent increase in serum GM-CSA when tested 24 h after E3 treatment. The majority of GM-CSA was adsorbed onto Concanavalin A-Sepharose 4B and was eluted by 0.2 M methyl-alpha-D-mannopyranoside, suggesting its glycoprotein nature. When E3-treated mouse serum was applied onto Sephacryl S-300 without any pretreatment, GM-CSA was detected as a sharp single peak with an apparent molecular weight of 440,000 daltons. When GM-CSA was treated with neuraminidase, however, and then applied to Sepharose CL-6B under disaggregating conditions (6 M guanidine HCl), the minimum molecular weight of the active component was estimated as 13,000 daltons.
The entry of environmental antigens into the lumen of the bursa of Fabricius was prevented by ligating the bursal duct prior to hatching (BDL: bursal duct ligation). The development of 'natural' serum agglutinins for bacteria and heteroerythrocytes was markedly suppressed by BDL. The antigen-specific recovery was observed by simultaneous administration of sterile antigens into the bursal lumen at the time of BDL. These results strongly suggest that the bursa of Fabricius is a major channel through which environmental antigens stimulate the immune system and induce the formation of 'natural' serum agglutinins.