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Biomedical subjects

T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 199 records · Page 11Linked to original sources
PubMed1987

Production and properties of a mouse monoclonal IgE antibody to Schistosoma japonicum.

A monoclonal IgE antibody was prepared by fusion of NS-1 myeloma cells with spleen cells of C3H/He mice immunized with an extract of adult worms of Schistosoma japonicum (Sj). The antibody was able to elicit passive cutaneous anaphylaxis in the rat skin against Sj with the highest titer of 1/256,000 in an ascitic form but did not cross-react with any of antigens extracted from S. mansoni, Fasciola hepatica, Paragoniumus westermani, or Trichinella spiralis. Western blot analysis indicated that the monoclonal IgE antibody recognized epitopes on molecules of 82 kDa, 97 kDa, 160 kDa, and 200 kDa, at least some of which were recognized by IgG antibodies of patients with chronic schistosomiasis japonica. The IgE antibody also recognized a 97-kDa antigen expressed on the surface of mechanically transformed schistosomula. Passive transfer of the antibody into mice in an early stage of challenge infection resulted in a partial but significant reduction of recovery of adult worms. However, similar treatment was not effective for the protection if the antibody was given in the postlung stage of the infection. Moreover, eosinophil-mediated damage to schistosomula was observed in vitro in the presence of the monoclonal anti-Sj IgE antibody, whereas the damage was not observed in the presence of another monoclonal IgE antibody with dinitrophenyl specificity.

Animals↗
PubMed1987

Paragonimus westermani: a comparative study on the migration route of the diploid and triploid types in the final hosts.

Recent studies on chromosomes have shown the presence of diploid and triploid types of Paragonimus westermani. To determine any possible biological differences between them, the migration route and development of the diploid type in the final hosts were compared with those of the triploid type. In the cat, the definitive host, larvae of the diploid type migrated to the abdominal wall, remained there for two weeks, and then migrated to the lung. In the rat, the abnormal host, some orally administered metacercariae of the diploid type made cysts in the lung and laid eggs, but the triploid type did not lay any eggs. Neither type of P. westermani migrated to the liver of the rat, in contrast to the previously reported fact that P. miyazakii and P. ohirai migrate to the liver and develop there. From these results, it seems likely that the two types of P. westermani are closely related.

Abdomen↗
PubMed1987

Comparison among lipid constituents in native LDL, ultra-water-soluble LDL, and vessel wall, and their significance in arteriosclerosis.

The lipid constituents in native low-density lipoproteins (LDL), ultra-water-soluble LDL (UWS-LDL), and aortic intimal tissues were compared. These lipoproteins were obtained from healthy persons and patients with atherosclerotic diseases. Also, aortic intimas were separated from arterial walls obtained within 5 hr after the donor's death. (1) From the native LDL, cholesterol esters (CE), triglycerides (TG), small amounts of free fatty cid (FFA), free cholesterol (CF), and phospholipids (PL) were demonstrable by iodine vapor on TLC, but from UWS-LDL the above lipids plus a new lipid (spot X) were observed between TG and FFA on TLC. And also, an unknown spot with the same Rf value as spot X was recognized on TLC of lipid extract from the atherosclerotic lesion, but not from the normal intima. (2) The production of spot X in UWS-LDL is probably related to the oxidation of lipids in native LDL. Also, the spot X in UWS-LDL and the spot X in the atherosclerotic lesions are probably related to the oxidation of CE in these lipids. (3) The existence of UWS-LDL is important to the initiation and probably the progression of atherosclerosis.

Aorta↗
PubMed1987

The experimental study of the coronary reperfusion in the acute myocardial ischemia: the feasibility of the myocardial salvage.

In order to know the feasibility of coronary reperfusion by thrombolysis or aorto-coronary bypass graft in the early stages of the acute myocardial infarction, we studied the effect of the coronary artery reperfusion to acutely ischemic myocardium induced by the coronary artery occlusion in ninety-five anesthetized open-chest dogs. The major factors determining the extent of the myocardial salvage by the reperfusion were the duration of the occlusion time and the degree of the reperfusion injury. These two determinants were analysed by coronary circulation, the regional myocardial function, the mitochondrial metabolism, mitochondrial Ca and Mg contents, and morphological findings of the myocardium by electron-microscopy. The regional myocardial contractility (% systolic shortening) and the mitochondrial metabolism (oxidative phosphorylation) were significantly damaged by the reperfusion more in 60 minute occlusion than in 30 minute occlusion, although the coronary circulation (coronary blood flow, regional myocardial blood flow and coronary vascular resistance) and myocardial gas contents (PO2, PCO2 and pH) in the ischemic myocardium induced by less than 60 minute occlusion were almost recovered to the pre-occluded level by 60 minutes after reperfusion. By 120 minute reperfusion, the ischemic damage calculated from mitochondrial Ca and Mg contents (MC index: 1-[Mg/Ca] ischemia/[Mg/Ca] non-ischemia) was not changed in 30 minute occlusion but was significantly deteriorated in 60 minute occlusion. Therefore, coronary reperfusion must be started within 60 minutes or less after occlusion. A supplementary way to protect the myocardium from ischemia is needed as soon as possible before reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

[Inhibition by KB-2796, a new Ca2+ entry blocker, of the contractile response of isolated cerebral and peripheral arteries in the dog].

In helical strips of dog cerebral and peripheral arteries, KB-2796 (1-[bis(4-fluorophenyl)-methyl]-4-(2,3,4-trimethoxybenzyl)piperazine dihydrochloride), a new Ca2+ entry blocker, inhibited the contractile responses induced by K+, prostaglandin (PG) F2 alpha and serotonin in a non-competitive manner. KB-2796 inhibited the contraction induced by K+ more effectively than those induced by PGF2 alpha or serotonin. In cerebral arteries, the inhibition produced by KB-2796 was more prominent than in peripheral arteries. In renal arteries, serotonin produced contractions in concentrations 200-1,200 times higher than those sufficient to contract the other arteries. KB-2796 inhibited renal arterial contractions induced by serotonin and K+ to a similar extent. In renal arteries depolarized by replacement of the entire amount of NaCl in the bathing medium with KCl, PGF2 alpha produced additional contraction of the artery, whereas serotonin did not contract the artery. These results suggest that KB-2796 inhibits the contractility of cerebroarterial smooth muscle more preferentially than that of other arteries. The contractile response to serotonin of the renal artery appears to be associated with the voltage-dependent influx of Ca2+ as suggested in the cerebral arteries.

Animals↗
PubMed1986

Selective inhibition by ionophore A23187 of the enzyme isomerization in the catalytic cycle of sarcoplasmic reticulum Ca2+-ATPase.

The effect of a lipophilic antibiotic, ionophore A23187, on the purified Ca2+-ATPase from sarcoplasmic reticulum was investigated. When the enzyme was pretreated with A23187 in the presence and absence of Ca2+, the Ca2+-dependent ATPase activity was inhibited almost completely, but the activity of the contaminating Mg2+-ATPase was unaffected. The steady state level of the phosphoenzyme (EP) from ATP or Pi was not substantially altered. When the pretreatment was performed in the presence of Ca2+, EP formation from ATP was only slightly retarded, but EP decomposition was strongly inhibited. Under these conditions, the accumulated EP was ADP-sensitive. EP formation from Pi after chelating of Ca2+ was quite slow, whereas EP once formed was in rapid equilibrium with Pi of the medium. On the other hand, when the pretreatment was performed in the absence of Ca2+, EP formation from ATP was extremely slow, but EP once formed was in rapid dynamic equilibrium with ATP of the medium. EP formation from Pi was very fast, and this EP was in rapid equilibrium with Pi of the medium. These results demonstrate that A23187 selectively inhibits isomerization of the enzyme between the high Ca2+-affinity form and the low Ca2+-affinity form in the catalytic cycle, whether or not the enzyme is phosphorylated. This suggests that interactions between the enzyme protein and the surrounding lipids could play a crucial role in this isomerization.

Adenosine Triphosphate↗
PubMed1986

Characterization of the phosphoenzyme that is involved in the Ca2+ -Ca2+ exchange catalyzed by the Ca2+ -ATPase of sarcoplasmic reticulum vesicles.

The rate of Ca2+ efflux was determined with 45Ca2+ -loaded sarcoplasmic reticulum vesicles (mainly with the light fraction of vesicles) at pH 6.5 and 0 degrees C. The efflux depended on external Ca2+, Mg2+, ATP and ADP, but it was not activated by AMP. The results indicate that the efflux is derived from Ca2+ -Ca2+ exchange mediated by the phosphoenzyme (EP) of membrane-bound Ca2+ -ATPase. EP was formed with Ca2+ -loaded vesicles (light fraction) under similar conditions without added ADP. The subsequent addition of EGTA and ADP induced triphasic EP dephosphorylation. Three species of EP (EP1, EP2, and EP3) were distinguished on the basis of this dephosphorylation kinetics, EP1, EP2, and EP3, corresponding to the first, second, and third phases of the dephosphorylation. Dephosphorylation of EP1 and EP2 resulted in stoichiometric ATP formation, while dephosphorylation of EP3 led to stoichiometric Pi liberation. The rate of Ca2+ efflux was compatible with that of EP2 dephosphorylation, whereas it was much lower than the rate of EP1 dephosphorylation and much higher than the rate of EP3 dephosphorylation. The intravesicular Ca2+ concentration dependence of the rate of EP2 dephosphorylation agreed with that of the rate of Ca2+ efflux. The results suggest that isomerization between EP1 and EP2 is the rate-limiting process in the Ca2+ -Ca2+ exchange and that EP3 is not involved in this exchange.

Adenosine Diphosphate↗
PubMed1986

Do protozoa conceal a high potency of nucleoside triphosphate hydrolysis present in Toxoplasma gondii?

ATP hydrolytic activity in whole cell homogenates of some protozoa was assayed in the presence or absence of dithiothreitol. The activities in all protozoan cell homogenates, except Toxoplasma gondii, ranged from 0.6 to 32 mumol/mg protein/hr, irrespective of the presence or absence of dithiothreitol. A remarkably higher activity, 11,690 mumol/mg protein/hr, was observed for T. gondii in the presence of dithiothreitol. These results indicate that the higher ATP hydrolytic potency observed for T. gondii is not universal to protozoa, rather it is unique to T. gondii.

Adenosine Triphosphate↗