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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 631 records · Page 35Linked to original sources
PubMed1984

Induction of lymphosarcoma in sheep inoculated with bovine leukaemia virus.

Five sheep were experimentally inoculated with BLV in order to study the humoral immune response in animals infected with bovine leukaemia virus (BLV). During experimental periods of 46 months, 2 sheep died with leukaemia and one sheep showed splenomegaly and proliferation of tumour cells. The other 2 sheep were clinically normal. All of the inoculated sheep developed antiviral antibodies 1 month after inoculation and BLV could be re-isolated in lymphocytes 2 to 3 months after inoculation. Antibody against glycoprotein antigen (gp51) of BLV appeared earlier than the antibody against protein antigen (p24) and antibody titres of the former were higher than those of the latter during the course of the experiment. The complement dependent antibody cytotoxicity test was performed for the detection of antibody against BLV-related cell membrane antigen with 2 different kinds of target cells; FLK cells which are foetal lamb kidney cells chronically infected with BLV and SF-28 cells which are sheep fibroblasts transformed with BLV in vitro. All 5 sheep developed cytotoxic antibodies against both types of cells. In sera from two leukaemic sheep, cytotoxic antibody titres against SF-28 cells gradually decreased 30 months after inoculation and finally became negative one to 3 months before they died of leukaemia. However, these leukaemic sheep persistently produced antibodies against gp51 and p24.

Animals↗
PubMed1984

Suppression of natural cytotoxic activity of lymphocytes from cattle and sheep during the progress of bovine leukosis.

Peripheral blood lymphocytes (PBL) from cattle and sheep exhibited natural cytotoxicity on a fetal lamb kidney (FLK) cell line that was persistently infected with bovine leukemia virus (BLV) by 20-h 51Cr release assay. This cytotoxic activity was tested using PBL from normal cattle and sheep or BLV-infected animals. Although cytotoxic activity was also found in PBL from normal animals and from BLV-infected, but clinically healthy animals, the activity in PBL from animals with persistent lymphocytosis or leukemic animals was markedly decreased. The cytotoxic activity of PBL from 3 sheep sequentially tested before and during the disease was found to decrease gradually with the progress of the disease, and finally no cytotoxic activity was found at the time of death due to leukemia. These results suggest that the natural cytotoxic activity in PBL may have a role in immunosurveillance for progress of the tumor.

Animals↗
PubMed1984

Pyrogenicity of yeast mannans in rabbits.

A few yeast mannans free from protein and phosphorus showed pyrogenic activity in rabbits although the extent of this activity was considerably lower than that of the bacterial lipopolysaccharides (LPS). The pyrogenic activity was not abolished by treatment with sodium deoxycholate. This result showed that the mannans themselves participated in the pyrogenicity, excluding any possibility of LPS contamination in the mannans. Concerning the relationship between chemical structure and pyrogenicity of these mannans, it was demonstrated that a mannan possessing a highly branched structure exhibited stronger pyrogenicity than that of a less branched one.

Animals↗
PubMed1984

Lethal effect of neutral mannan fraction of bakers' yeast in mice.

A simple polysaccharide, the neutral mannan from Saccharomyces cerevisiae wild type strain (WNM) was found to kill ddY strain mice by intravenous administration, showing a LD50 value of 12.2 mg/kg. On the other hand, the acidic mannan fraction from the same yeast containing phosphate (WAM025), and chemically phosphorylated WNM (WNM-P) were practically non-toxic. Concerning the relationship between chemical structure and lethal effect of these mannans, it was demonstrated that a mannan possessing a highly branched structure exhibited stronger lethality than those with less branched structures. Against C3H/HeJ strain mice with no responsiveness to lipopolysaccharide, the LD50 value of WNM was as high as 75 mg/kg. Pretreatment with 500 mg/kg of D-mannose, N-acetyl-D-glucosamine, D-galactose, and L-fucose prevented mice from the lethal effects of WNM. However, WNM (LD100) did not show any lethal effect in mice for 2 to 12 hr after treatment with dexamethasone, an anti-inflammatory steroid.

Anaphylaxis↗
PubMed1984

Growth-inhibition of leukemia L-1210 ascites tumor by combination of carrageenan and mitomycin C in vivo.

A purified i-carrageenan prepared by means of pronase digestion and fractional precipitation with KCl was investigated for its growth-inhibitory effect on mouse leukemia L-1210 transplanted in (C57BL/6 x DBA/2)F1 (BDF1) mice. This carrageenan specimen was not growth-inhibitory on this tumor when it was administered alone in a dose of 0.1 to 10 mg/kg/d, 4 times. However, in combination, with a small amount of mitomycin C, 0.25 mg/kg/d, a remarkable tumor growth-inhibition has manifested affording a complete regression of this tumor. Acid phosphatase alpha-galactosidase and active oxygen generation activities of the peritoneal exudate cells in the carrageenan-administered mice were remarkably higher than those of the control mice. Therefore, the booster effect of this carrageenan preparation on antitumor activity of mitomycin C is assumed to be associated with the inflammatory activity of this sulfated polysaccharide.

Acid Phosphatase↗
PubMed1984

In vitro cytolysis of MM46 tumor cells by mouse phagocytes activated by acidic mannan fraction of bakers' yeast.

An acidic mannan from bakers' yeast designated as WAM025 was investigated for its augmentative effect on cytolytic activity of phagocytes obtained from the peritoneal cavity of C3H/He strain mice, which had been administered i.p. with this acidic polysaccharide, 150 mg/kg/d, 5 and 10 times. The result of assay for the cytolytic effect of WAM025-activated phagocytes by measuring the amounts of 3H-uridine of the MM46 tumor cells indicated that a marked lysis of the target cells took place by a 24-h incubation with the activated phagocytes and that a decrease of this effect was observed by the additions of either phagocytic inhibitors or active oxygen scavengers. Because generation of active oxygens from the WAM025-activated phagocytes was also diminished by the additions of the same inhibitors and scavengers, it indicated that active oxygens participated in an important role in the cytolytic effect displayed by the WAM025-activated phagocytes.

Animals↗
PubMed1984

Open-loop analysis of PaCO2 oscillation in the dog.

Venous CO2 loading and/or unloading using an artificial lung was performed on dogs to evaluate whether changes in the rate of carbon dioxide output (VCO2) can be involved in the control of respiration. As the signal providing VCO2 information, small fluctuations in arterial PCO2 (delta PaCO2) which synchronized with the respiratory cycle were estimated from both the mean PaCO2 and the fluctuations in arterial pH (delta pH) measured with a catheter tip ISFET (ion sensitive field-effect transistor) pH sensor inserted in the common carotid artery. The open-loop method was used to analyze the effects of various respiratory parameters such as VCO2, tidal volume, and respiratory frequency on the changes in delta pH and delta PaCO2. Findings are: (1) delta PaCO2 was linearly proportional to VCO2 while the correlation between delta pH and VCO2 was less linear, (2) magnitude of delta pH was dependent on the changes in tidal volume while delta PaCO2 was not, (3) both the amplitude and the positive slope of PaCO2 oscillation were functions of respiratory frequency. These results suggest the possibility that if VCO2 itself takes part in the control of ventilation, it will be CO2 oscillation which links ventilation with VCO2.

Animals↗
PubMed1984

In vitro and in vivo detection of infectious pancreatic necrosis virus in fish by enzyme-linked immunosorbent assay.

A double antibody enzyme-linked immunosorbent assay (ELISA) was used to detect infectious pancreatic necrosis virus (IPNV). The ELISA detected VR299 strain of IPNV at a dose of 10 to 20 ng of purified IPNV protein or 10(4) TCID50 in tissue culture fluid. Specificity of ELISA was demonstrated by an ELISA inhibition test. The ELISA did not detect infectious hematopoietic necrosis virus. Normal cell culture fluid and virus-non-inoculated rainbow trout (Salmo gairdneri Richardson) homogenate did not react in the test system. The IPNV was detected in rainbow trout fry inoculated with IPNV. Although infective virus titer in fish decreased rapidly 1 week after inoculation, IPNV antigen was detected by ELISA for 15 days. The IPNV antigen was detected in the fish tissue after inactivation of infective virus. The ELISA is a rapid and reliable method for the diagnosis of IPNV infection.

Animals↗
PubMed1984

Protection by vaccination against bovine leukemia virus infection in sheep.

Four preparations were tested as potential vaccines to protect sheep against bovine leukemia virus (BLV) infection. Purified glycoprotein (gp) 51 and protein (p) 24 antigens from the virus and glutaraldehyde-fixed fetal lamb kidney (FLK) cells chronically infected with BLV or sheep fibroblasts transformed with BLV (SF-28 cells) were used to inoculate 12 sheep. Each vaccine was given 3 times 2 and 4 weeks apart to 3 sheep. Six sheep vaccinated with gp51 antigen or fixed FLK cells developed complement-fixing antibody against gp51; the titers ranged from 1:8 to 1:128 at the time of virus challenge exposure at postinoculation week 9. Although the 6 sheep inoculated with p24 antigen or fixed SF-28 cells developed antibody against the respective inoculum, none of these sheep had gp51 antibody at the time of challenge exposure. All 12 vaccinated and 2 control sheep were challenge exposed with BLV-infected lymphocytes, and cells from the sheep subsequently were tested for infection by syncytium assay. Sheep inoculated with gp51 antigen or FLK cells were protected, but sheep inoculated with p24 antigen or SF-28 cells became infected. The cytotoxic activity of lymphocytes from protected and nonprotected sheep was not different from that of normal sheep. Seemingly, purified gp51 antigen or fixed FLK cells were capable of preventing BLV infection in sheep. Humoral immune responses to gp51 appears to have an important role in protection against BLV infection, whereas cytotoxic activity of lymphocytes does not.

Animals↗
PubMed1984

[Relationship between CT findings and consciousness in patients with hypertensive putamen hemorrhage].

The authors studied 66 patients with hypertensive putamen hemorrhage and noted a close relationship between the CT classification according to the shape of the suprasellar cistern (S) and the third ventricle (III), and the state of altered consciousness: when S is not deformed and III is identified in CT images, the patient may be in a clear or confusional state; if S is not deformed but III is not identified or is packed with hematoma, consciousness may be somnolent or stuporous; if S is deformed and III is not identified or is packed with hematoma, the patient may be in a semicomatose or comatose state. However, within several hours after onset there are exceptional cases in which the states of consciousness do not correlate with the CT findings. In these cases, however, with conservative therapy the state of consciousness corresponded well with the CT findings. From the neurosurgical points of view, immediate removal of the hematoma is required when the patient's consciousness is relatively good despite of large hematoma. If at the acute stage the state of consciousness, which corresponded well with the CT findings at initial examination, has deteriorated, rebleeding or enlargement of hematoma must be suspected.

Brain↗
PubMed1984

Extracellular virulence factors of fish Vibrio: relationships between toxic material, hemolysin, and proteolytic enzyme.

Biological activities of cell-free culture filtrate of 3 virulent strains of fish Vibrio were examined to determine the relationship to the pathogenesis of fish vibriosis. Among the 3 strains examined, V anguillarum strains NCMB6 and NCMB571 produced hemolysin and protease, whereas V ordalii strain N7802 did not. Culture filtrate of strain NCMB571 were lethal to rainbow trout and produced a cytotoxic effect on fish cell line. Results revealed that the extracellular products may be involved in the pathogenesis of fish vibriosis.

Animals↗
PubMed1984

Partial purification of extracellular toxic material of fish Vibrio.

Hemolytic activity of 3 pathogenic strains, of fish Vibrio commonly associated with vibriosis (V anguillarum NCMB6 and NCMB571 strains, and Vibrio sp N7802 strain) was examined, using chicken and mammalian erythrocytes. Vibrio strains NCMB6 and NCMB571 and their culture filtrates had hemolytic activity against 8 kinds of erythrocytes tested, whereas Vibrio strain N7802 produced only a little amount of hemolysin. Strain NCMB571 culture filtrate and its material partially purified by column chromatography were lethal in mice. From 2 peaks of protein, hemolysin was recovered from the 1st peak, which coincided with toxicity in mice. Heat-inactivation of culture filtrate indicated that hemolytic materials may be thermolabile proteins, but that toxic material may be comparatively thermostable.

Animals↗
PubMed1984

[Grading of tricuspid regurgitation by pulsed Doppler echocardiography and liver function tests].

Recently, pulsed Doppler echocardiography has been used for the quantitative evaluation of tricuspid regurgitation (TR). However, there are some problems about the clinical significance of TR diagnosed by Doppler examination probably because of the excellent sensitivity in detecting TR. In the present study, we used liver function tests as an indicator of the visceral damage caused by TR and compared them to the severity of TR estimated by Doppler examination. Forty Doppler examinations were performed in 33 cardiac patients including seven, in which the examinations were repeated because the severity of TR changed during the clinical course. The severity of TR was classified into four grades according to the maximal extent of the regurgitant signal. Abnormal liver function was defined by the abnormalities of at least one of the following six tests: cholinesterase (CHE), gamma-GTP, leucine aminopeptidase (LAP), total bilirubin, alkaline phosphatase and GPT. Abnormal liver function tests were present in one of eight patients without TR, two of 10 with 1 + TR, four of seven with 2 + TR, seven of eight with 3 + TR, and six of seven with 4 + TR. The incidence of abnormal liver function tests increased parallel to the grade of TR and was very frequent in patients with 3 + or 4 + TR. TR diagnosed as greater than 3 + by Doppler examination is considered to have an important clinical significance and an indication of the intensive therapy.

Cholinesterases↗
PubMed1984

[Atrial septal defect associated with an abnormal chamber of the right ventricle: report of a case].

A case of atrial septal defect associated with an abnormal chamber behind the right ventricle, which was heretofore undescribed, was reported. A 41-year-old woman was admitted to our hospital for the evaluation of a heart murmur. A Levine 3/6 ejection systolic murmur and a fixed splitting of the second heart sound were audible. Two-dimensional echocardiography disclosed an atrial septal defect and an abnormal chamber behind the right ventricle. This accessory chamber communicating with the right atrium was separated from the right ventricle by a membranous structure. The motion of this membrane showed a wide excursion just like that of the atrio-ventricular valve. On the M-mode echocardiogram, the anterior tricuspid leaflet and this membrane were recorded simultaneously without intervening septal echoes and this finding was very similar to that obtained in the single ventricle. Cardiac catheterization revealed that the pressure pattern in the abnormal chamber was that of the right atrium but its intracardiac electrocardiogram showed a right ventricular pattern. The complex morphological aspect of this case was confirmed by angiography and surgery. The developmental process of this very unusual anomaly is not clear, but it may be a kind of congenital anomaly related to Ebstein's anomaly.

Adult↗