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Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 1,297 records · Page 72Linked to original sources
PubMed1980

Formation of mononuclear phagocyte (macrophage) colonies by mouse spleen cells in liquid culture. I. Kinetics of appearance of colonies and characterization of macrophage colony-forming cells.

When spleen cells of the adult mouse were tested for the formation of mononuclear phagocyte (macrophage) colonies by the liquid culture technique with an incubation period of 7--8 days, about 100 macrophage colonies were produced from 1 X 10(6) cells. The number of macrophage colonies appearing after 2 days of incubation was small, but thereafter increased progressively up to at least 8 days. In the later stages of incubation (after day 6) large colonies consisting of more than 100 cells appeared. Macrophage colonies in the early stages consisted almost solely of macrophages. On day 6 significant numbers of small round mononuclear cells with no detectable phagocytic activity were seen in the center of large colonies, and by day 8 marked crowding of these cells had occurred. The peripheral region of the large colonies consisted mainly of macrophages and the intermediate region of middle-sized round or slightly stretched cells with weak phagocytic activity. Approximately two-thirds of the colony-forming cells still remained after glass-adherent cells were removed from the spleen cells by passing over a glass-bead column. In cultures of glass-nonadherent cells macrophage colonies were not generated in the early stage. The number of colony-forming cells did not change significantly even after actively phagocytic cells were rigorously removed from the spleen cells. In addition, no macrophage colonies were generated in cultures of spleen cells treated with mitomycin C.

Animals↗
PubMed1980

Microbial adjuvant and autoimmunity. IV. Production of lesions in the exocrine pancreas of mice by repeated injection of syngeneic pancreatic extract together with the capsular polysaccharide of Klebsiella pneumoniae.

Definite lesions in the exocrine pancreas were produced when SMA mice were immunized eight times at intervals of 30 days with a mixture of extract of pooled pancreas from syngeneic mice and the capsular polysaccharide of Klebsiella pneumoniae type I Kasuya strain (CPS-K), whereas no pancreatic lesions were produced in mice given CPS-K alone or pancreatic extract alone. The typical histological changes were characterized by infiltration with lymphocytes, plasma cells, and other mononuclear cells, degeneration and lysis of the acinar cells, destruction of the lobular architecture, and replacement of fatty tissue and fibrous connective tissue. The endocrine islets were well preserved. No specific histological changes were produced in the organs other than the pancreas in these mice. Most of mice immunized with pancreatic extract mixed with CPS-K produced serum precipitins to syngeneic pancreatic antigens. However, severe pancreatic lesions were also produced in mice showing no definite precipitin production.

Adjuvants, Immunologic↗
PubMed1980

Interferon and cytotoxic factor (cytotoxin) released in the blood of mice infected with Mycobacterium bovis BCG. III. Interferon and cytotoxin induced by the specific antigen as compared with those induced by bacterial lipopolysaccharide.

The time course of development and decline of the ability of BCG-infected mice to produce interferon in the serum in response to the intravenous infection of purified protein derivative of tuberculin (PPD) was very similar to that of their systemic hypersensitivity to PPD. A cytotoxic factor (cytotoxin) was produced in parallel with interferon in the serum of BCG-infected mice after stimulation with PPD. The duration of the period in which cytotoxin-production responsiveness to PPD was definitely detectable was much shorter than that for interferon-production responsiveness although the periods for the maximum production of interferon and cytotoxin coincided. The kinetics of release of interferon in the serum of BCG-infected mice after stimulation with PPD did not parallel that of release of cytotoxin. The four kinds of activities, interferons and cytotoxins induced by PPD and lipopolysaccharide (LPS) in the serum of BCG-infected mice, were compared for their stability to heating at 56 C and to treatment at pH 2. The kinetics of inactivation of these four activities differed significantly, when the serum was either heated at 56 C or treated at pH 2. Interferon produced in response to LPS could be neutralized by anti-L cell(NDV) interferon rabbit serum as easily as L cell (NDV) interferon, 16 times as much antiserum was required to neutralize the same amount of interferon in response to PPD, but cytotoxins induced by PPD and LPS were not neutralized at all by the antiserum. From these findings it is thought likely that interferons and cytotoxins induced by PPD and LPS in the serum of BCG-infected mice are different substances, although the antigenic relationship between cytotoxins induced by PPD and LPS remains unknown.

Animals↗
PubMed1980

Mitral cleft in ostium primum atrial septal defect assessed by cross-sectional echocardiography.

We attempted to detect mitral deformities in ostium primum atrial septal defect using real-time cross-sectional echocardiography. Transverse sections of the anterior mitral leaflet echo were examined in 11 patients with this malformation who subsequently received surgical treatment. The section for observing the transverse view of te anterior leaflet was along the sagittal plane of the body, because of the deformity of the mitral annulus. Each echocardiographic finding was compared with the surgical and angiographic findings. On the echocardiogram, the superior and inferior parts of the anterior mitral leaflet separated into two parts during diastole in all patients with mitral cleft. Thin linear echoes connected the ridges of the cleft and the ventricular septum in seven patients in whom the accessory chordae at that area were revealed at surgery. The systolic configuration of the anterior leaflet echo varied among the patients. The severity of the miral regurgitation seemed to relate not only to the size of the cleft but also to the systolic configuration of the anterior mitral leaflet. After surgery, diastolic separation of the anterior leaflet echo was no longer observed. However, the abnormal systolic configuration of the anterior leaflet was unchanged.

Adolescent↗
PubMed1980

Age-hardening of dental Ag-Pd-Cu-Au alloys.

Age-hardening mechanisms of dental Ag-Pd-Cu-Au alloys were investigated by means of electron microscopic observations. Hardening was due to the precipitation of the L10 type CuPd-ordered platelet in the grain interior and to the discontinuous precipitation at the grain boundary. The characteristics of age-hardening curves were determined by rates of continuous and discontinuous precipitation.

Copper↗
PubMed1979

Transmission of chronic spongiform encephalopathy with kuru plaques from humans to small rodents.

An unusual case of spongiform encephalopathy was transmitted directly from a human to rats and mice. After serial passages, incubation periods were shortened to about six months in rats and four months in mice. Clinical symptoms were similar in rats and mice, including ruffled fur, arched back, bradykinesia, and hind limb paralysis. Pathologically, a spongy state, proliferation of astrocytes, and neuronal changes were observed. Electron microscopic observation of the parietal cortex of rats and mice disclosed many membrane-bound vacuoles in the neuropil, predominantly in dendrites. In the pons of mice, intramyelinic vacuoles and accumulation of extracellular fluid were prominent. The clinicopathological symptoms of the affected animals resembled those in other experimental spongiform encephalopathies, especially scrapie.

Animals↗
PubMed1979

Adult type mucolipidosis with beta-galactosidase and sialidase deficiency. Histological and biochemical studies.

A case of adult type mucolipidosis with beta-galactosidase and sialidase deficiency is described. This patient, a woman aged 20, had mental retardation, macular cherry-red spots, corneal clouding, gargoyle-like face, cerebellar ataxia, myoclonus and convulsions beginning at the age of 14. Bony deformities, vacuoles in the peripheral lymphocyte and foamy cells in the bone marrow were also noted. Biopsy study of the sural nerve and vermiform appendix disclosed many vacuoles in almost every kind of cells, although the accumulated substance in these vacuoles could not be characterized histochemically or ultrastructurally. Deficient leukocyte beta-galactosidase and sialidase were confirmed. There was increased urinary sialoglycopeptide and increased siliac acid and hexosamine in the glycoprotein of lymphocytes. Leukocytes sialidase activites of the parents were 30 to 50% of the control values. These results suggest a genetic defect of sialidase.

Adult↗