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T Kanazawa

Publications and source records attributed to T Kanazawa.

At least 145 records · Page 8Linked to original sources
PubMed1992

Transformed growth phenotype of mouse mammary epithelium in primary culture induced by specific fetal mesenchymes.

When mesenchyme from fetal mammary or salivary gland is implanted into adult mouse mammary gland, adjacent epithelium responds with intense hyperplasia. The hyperplastic cells are more vulnerable than are non-stimulated cells to transformation in vivo by a chemical carcinogen or by mammary tumor virus. This system provides a potentially useful model for determining how stroma contributes to mammary tumorigenesis. We have developed co-culture systems and used them to investigate in more detail the nature of the signal produced by the mesenchyme cells. Monolayers of mesenchyme cells were prepared on tissue-culture wells. The mesenchyme cells were trapped on the surface by a thin overlay of agarose. Primary mammary epithelial cells were cultured atop this barrier layer, either as organoids in collagen gels for assessment of anchorage-dependent growth, or as single-cell dispersions in soft agarose for assessment of anchorage-independent growth. Our procedures for assay of anchorage-independent growth allow us for the first time to detect and measure this transformation-defining characteristic in non-immortalized mammary epithelial cells in primary culture. Fetal mammary fat pad precursor tissue and fetal salivary mesenchyme both stimulated anchorage-dependent growth of mammary epithelium, with cell number increasing as much as fifteenfold during a 6-day culture period. These same fetal tissues also stimulated anchorage-independent growth of the mammary epithelial cells, with colony-forming efficiencies of up to 40% in co-cultures with salivary mesenchyme. No colonies formed in the absence of mesenchyme. Cells of colonies contained keratin, which indicates that the colonies grew from epithelial cells and not from a contaminant of another cell type. When co-cultured epithelial cells were subsequently re-cultured in the absence of mesenchyme, they lost their ability to grow independent of anchorage. No colonies grew in co-cultures with fetal cells from heart, kidney, or lung, which is consistent with the lack of stimulation by these tissues in the mammary gland in vivo. A tumor promoter, 12-O-tetradecanoylphorbol acetate (TPA), also caused anchorage-independent growth of the dispersed mammary epithelial cells. Culture medium conditioned by primary or early-passage salivary mesenchyme cells was capable of stimulating growth under both anchorage-dependent and anchorage-independent conditions, confirming that these effects are mediated by a paracrine factor. The results indicate that stimulatory fetal mesenchymes produce soluble molecules that act analogously to transforming growth factors.

Animals↗
PubMed1992

Larvicidal properties of macrophages induced by cloned murine schistosomal egg antigen-specific CD4 positive T-helper lymphocytes.

The role of T-helper (TH) lymphocytes in activating peritoneal macrophages (PM) to kill larvae of the helminth Schistosoma mansoni (schistosomula) was investigated with the use of egg antigen-specific CD4 positive TH clones of both the TH1 and TH2 types. Results showed that stimulated TH1 clones, in exceedingly small numbers, or supernatants thereof, conferred on PM the ability to kill schistosomula. The molecule responsible for PM activation was found to be interferon-gamma (IFN-gamma). IFN-gamma-induced PM larvicidal activity was dependent on live cells, energy, as well as protein synthesis, and appeared to be mediated by toxic nitrogen metabolites. In contrast, egg antigen-specific TH2 clones, or their supernants, failed to induce PM larval killing, as they did not secrete IFN-gamma, or any equivalent macrophage activating factor. We postulate a mechanism by which egg antigen-specific TH1 clones may be capable of playing a critical role in the resistance to schistosomal reinfection through IFN-gamma-mediated activation of macrophage helminthotoxicity.

Animals↗
PubMed1992

[A case of retroperitoneal teratoma showing high level of CA19-9].

We report a case retroperitoneal mature teratoma showing an abnormally high CA19-9 (carbohydrate antigen 19-9) serum level in a 30-year-old woman. She was hospitalized for an episode of left upper abdominal pain. High CA19-9 tissue level and immunohistochemical findings were found in removed tissue. This case is the third report of a CA19-9-producing teratoma and literature was reviewed and discussed.

Adult↗
PubMed1991

The cell-mediated response to schistosomal antigens at the clonal level. In vivo functions of cloned murine egg antigen-specific CD4+ T helper type 1 lymphocytes.

It is now well established that the granulomatous inflammation surrounding the eggs of Schistosoma mansoni is mediated by Th lymphocytes. Our laboratory has recently cloned murine CD4+ Th cells specific for schistosomal egg Ag (SEA). In the current study, SEA-specific IL-2-producing Th1 clones were tested for their ability to mediate local delayed-type hypersensitivity (DTH) reactions, as well as granuloma formation in vivo. Marked delayed-onset erythema and induration developed in footpads of normal syngeneic hosts injected with SEA together with SEA-specific Th1 clones. Histologic examination of these lesions revealed typical, predominantly mononuclear, cell infiltrates characteristic of DTH reactions. Conversely, no reactions were observed in allogeneic hosts, in the absence of SEA, or with the use of a control Th1 clone. Moreover, adoptive transfer of cloned SEA-specific Th1 cells to normal syngeneic mice mediated, in 4 days, the formation of vigorous granulomas around schistosomal eggs embolized in the lungs. Such granulomas, which were quantitated by computer-assisted morphometric analysis, were comparable in size to those elicited by lung-embolized eggs in SEA/CFA-immunized mice. In contrast, significantly smaller granulomas were observed in normal recipients of eggs plus a control Th1 clone or of eggs alone. Our data indicate that Ag-specific, MHC-restricted, local DTH reactions, as well as egg granuloma formation in vivo, can be mediated by monoclonal SEA-specific Th1 cells. They suggest that T cell sensitization to only small numbers of SEA determinants may be sufficient to elicit the hepatointestinal granulomatous inflammation associated with schistosomiasis.

Animals↗
PubMed1991

Murine monoclonal antibodies reactive with staphylococcal enterotoxins A, B, C2, D, and E.

By fusion of mouse spleen cells immunized with five different staphylococcal enterotoxins (SEA, SEB, SEC2, SED, and SEE) with myeloma cells, we obtained 15 hybridomas producing monoclonal antibodies (mAbs). Four mAbs were reactive with both SEA and SEE, whereas 8 mAbs were reactive with SEB and SEC2. One mAb reacted with SEA, SED, and SEE. The other two mAbs were found to be reactive with all five serotypes of SEs. The mAbs specific for five serotypes of SEs were found to be most reactive with SED, reactive with SEA, and slightly less reactive with SEB, SEC2, and SEE. Those mAbs with specificities for all serotypes of SEs may be valuable to prepare immunoadsorbent(s) for isolation of SEs and to detect SEs in foods and clinical specimens involved in outbreaks of staphylococcal food poisoning.

Animals↗
PubMed1991

Inhibition by A23187 of conformational changes involved in the Ca(2+)-induced activation of sarcoplasmic reticulum Ca(2+)-ATPase.

We previously showed that A23187 in high ionophore/protein ratios almost completely inhibits the sarcoplasmic reticulum Ca(2+)-ATPase [Hara, H. & Kanazawa, T. (1986) J. Biol. Chem. 261, 16584-16590]. In an attempt to obtain information on the mechanism of this inhibition, the effects of A23187 on conformational changes involved in the Ca(2+)-induced activation of the enzyme were investigated. The purified enzyme from sarcoplasmic reticulum of rabbit skeletal muscle as well as the purified enzyme labeled with fluorescein 5-isothiocyanate (FITC) were preincubated with A23187 in the absence of Ca2+ at pH 7.0 and 0 degrees C for 45 min. The activation of the enzyme following addition of CaCl2 was assessed by determining the capacity for rapid formation of phosphoenzyme from ATP. This activation was strongly inhibited by the preincubation with A23187. This indicates that the previously observed inhibition of the Ca(2+)-ATPase is mostly due to hindrance of the Ca(2+)-induced activation of the enzyme. In the control, in which the FITC-labeled enzyme was preincubated without A23187, the fluorescence intensity of the bound FITC decreased in a biphasic manner upon addition of CaCl2. The first rapid phase of this fluorescence drop was unaffected by A23187, whereas its second slow phase was almost completely inhibited by this drug. These results show that the Ca(2+)-dependent conformational change is biphasic and that the second slow phase (but not the first rapid phase) of this conformational change is inhibited by A23187. This suggests that the observed inhibition of Ca2+ activation is attributed to hindrance of the second slow phase of the Ca(2+)-dependent conformational change.

Animals↗
PubMed1991

Effects of low-density lipoprotein from normal rabbits on hypercholesterolemia and the development of atherosclerosis.

To clarify whether or not normal LDL separated from normal rabbits is atherogenic, 0.75 mg of normal LDL-cholesterol in 6 ml of 0.85% saline and 6 ml of saline alone were injected every day for 5 weeks into the auricular vein of two groups of rabbits, respectively. The inoculated rabbits were fed a standard diet containing 0.5 and 1% cholesterol. Blood was drawn before injection and at 1, 2, 3 and 5 week intervals thereafter. After 5 weeks, all rabbits were sacrificed. Following exsanguination, the aorta was stained by Sudan III. The Sudan III staining was more extensive in rabbits injected with saline than in those that received LDL. In addition, plasma cholesterol, plasma phospholipid, VLDL-cholesterol and LDL-cholesterol levels were lower in LDL-injected rabbits than in those injected with saline. But HDL-cholesterol levels were not significantly different between LDL-cholesterol and saline-injected rabbits. Although the exact cause of antiatherogenic effect of normal LDL is not clear, it seems reasonable to suggest that at least some normal LDL acts as a 'good' lipoprotein, namely antiatherogenic lipoprotein, in our experimental protocol.

Animals↗
PubMed1991

The pathophysiology of myocardial stunning: reversibility, accumulation and continuity of the ischemic myocardial damage after reperfusion.

In order to understand the pathophysiology of myocardial stunning, reversibility, accumulation and continuity of ischemic myocardial damage after reperfusion should be studied. Then, to analyze these three factors, myocardial function, metabolism and morphology under ischemia and reperfusion were studied in anesthetized, open-chest dogs. When myocardial ischemia was induced by occlusion of the left anterior descending coronary artery, percentage regional systolic shortening (%SS) of ischemic myocardium sharply decreased and became stable 10 min after occlusion. After reperfusion, ischemic myocardium showed active shortening after within 30-min occlusion, but did not after more than 60-min occlusion. During 90-min of ischemia, extracellular K+ concentration (Ke) steeply increased for first 10 min and was almost stable for next 10 min. Then, Ke straightly increased till 90 min. Metabolic rates, calculated from myocardial tissue CO2 and pH, steeply increased for first 20 min and sharply decreased for next 10 min. After 30 min, these two variables were almost stable, near zero. By electron-microscopy with cytochemistry, distribution of Na/K ATPase to myocardial cell membrane was observed to be almost after 15-min occlusion but distinctly sparse with destruction of cell membrane after 30-min occlusion. Therefore, irreversible myocardial damage appears after about 20-min ischemia and is almost complete after 60 min. Reversibility of damage to ischemic myocardium after reperfusion may mainly occur within 60-min ischemia. Although stunned myocardium in a narrow sense is may appear after reperfusion within less than 20-min of ischemia, stunned myocardium in a broad sense may appear within less than 60-min ischemia. When reversible myocardial ischemia (4- or 15-min occlusion) was repeated after short time intervals (20-min reperfusion), %SS of ischemic myocardium was gradually decreased with each ischemic episode. Active shortening of ischemic myocardium disappeared after more than two episodes of 15-min occlusion. Fluctuation of PCO2, pH and Ke of ischemic myocardium was gradually depressed with each occlusion. Metabolic viability of ischemic myocardium was cumulatively depressed by repeated brief occlusion. Naturally, myocardial damage was more severe after repeated 15-min occlusion than after 4-min occlusion. Accumulation of ischemic myocardial damage may arise as brief ischemia, which only induces reversible damage, is repeated. At last, continuity of ischemic myocardial damage was studied. The effect of 5-min occlusion to %SS of ischemic myocardium was apparently reversed after 90-min reperfusion. Early contractile failure was advanced even after very short duration of ischemia. Thus, myocardial function will be latently damaged.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Role of renomedullary thromboxane A2 in development of doca-salt hypertension.

To clarify the role of renal thromboxane (TX)A2 in the development of deoxycorticosterone acetate (DOCA)-salt induced hypertension, relationship between systolic blood pressure and the synthesis of renal TXA2 was investigated in 18 rats without and with OKY-046 administration which suppressed the synthesis of renal TXA2. Systolic blood pressure was significantly higher in DOCA-salt group than in control and OKY groups. The synthesis of 6-keto-prostaglandin(PG)F1 alpha and TXB2 in both renal arteries and cortical slices were more enhanced in DOCA-salt and OKY groups than in control group, but there was no significant difference between DOCA-salt and OKY groups. In contrast, the synthesis of 6-keto-PGF1 alpha in renomedullary slices did not vary significantly among three groups, and that of TXB2 was more increased in DOCA-salt group than in control and OKY groups. The cumulative sodium retention was significantly greater in DOCA-salt group than in control group. Administration of OKY-046 reduced the cumulative sodium retention in DOCA-salt rats by 45% toward that of the control group. These results might suggest that the enhanced production of renomedullary TXB2 was important to the development of DOCA-salt induced hypertension.

Animals↗
PubMed1991

[Orthostatic purpura: report of two cases].

Two patients with orthostatic purpura were reported. Case 1: A 47-year-old man was admitted to our institution because of multiple purpuric eruptions over the legs after the long periods of sitting or standing. Bleeding time was 4.0 min. Platelet aggregation induced by ADP was disaggregated and no aggregation was observed when induced by collagen and epinephrine. He was diagnosed as having release abnormality of the platelets caused by glutathione administered for treatment of liver damage for several years. Purpura, however, appeared even though platelet function became normal after discontinuing glutathione. Purpura proved to be induced by the long periods of sitting or standing. Case 2: A 37-year-old woman was admitted to our hospital because of purpuric eruptions over the legs for three years. Bleeding time was 2.0 min. Platelet aggregation induced by ADP, epinephrine, collagen and ristocetin was normal. Purpura was caused by long periods of standing without movement. Wearing elastic pantyhose showed reduced appearance of the purpura. Biopsy specimens from both patients revealed no abnormal findings. Both patients had no abnormal results in coagulation studies. Purpura seemed to be caused by the increased capillary pressure after the prolonged periods of standing. No case report concerning orthostatic purpura or mechanical purpura has been published.

Adult↗
PubMed1991

[Evaluation of the results of extracorporeal shock-wave lithotripsy (ESWL) for solitary upper urinary tract stone].

We performed extracorporeal shock-wave lithotripsy (ESWL) on 1,701 patients in a total of 2,438 sessions using the Dornier kidney lithotriptor Model HM III from July 1985 to the end of June 1990. Among the patients with a solitary stone, 1,200 cases were available for the follow-up study in which the results of ESWL were analyzed according to the location and size of the stone. ESWL performed against stones at pelvis and calyces gave the best results. The results obtained on stones less than 20 mm in diameter were especially favorable with a success rate of 84%. ESWL performed against ureter stones showed poor results with a success rate of 62% for the stones smaller than 20 mm in diameter. We further studied the results of ESWL performed against ureter stones by dividing the patients into three groups: the patients treated in situ, the patients with ureteral stents and the patients with D-J stents. The results for stones larger than 10 mm in diameter were significantly better in the patients with D-J stents than in the patients treated in situ or the patients with ureteral stents. Among the patients treated in situ, the results were significantly worse for impacted stones than for non-impacted stones when the stone size was 10-20 mm in diameter.

Evaluation Studies as Topic↗
PubMed1990

Characterization of the substrate-induced conformational change of N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine-labeled sarcoplasmic reticulum Ca2(+)-ATPase by using different kinds of substrate.

Cys-674 of the sarcoplasmic reticulum Ca2(+)-ATPase was labeled with N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine without a loss of the catalytic activity, and changes in the fluorescence intensity upon addition of seven kinds of substrate were followed by the stopped-flow method. The steady-state fluorescence intensity and anisotropy were also determined. When Ca2+ was present, the fluorescence intensity and anisotropy decreased greatly upon addition of any substrate used. The observed affinity for each substrate agreed with the previously observed affinity of the catalytic site. The fluorescence drop induced by the adenine nucleotides, ATP and adenosine 5'-(beta, gamma-methylene)triphosphate (a nonhydrolyzable ATP analog), was much faster than that induced by other substrates. The ATP-induced fluorescence drop preceded phosphoenzyme formation when the ATP concentration was high, but the fluorescence drop coincided with phosphoenzyme formation when it was slowed by reducing ATP concentrations. The fluorescence drop induced by ITP or acetyl phosphate was slow even at high concentrations of the substrate, and it coincided with phosphoenzyme formation. When Ca2+ was absent, the fluorescence intensity and anisotropy decreased only slightly upon addition of any substrate other than the adenine nucleotides. They decreased substantially upon addition of the adenine nucleotides, but the kinetics of this fluorescence drop were quite different from that of the fluorescence drop induced by any substrate in the presence of Ca2+. These results show that the conformational change, which makes the bound label less constrained, is induced by substrate binding to the catalytic site of the Ca2(+)-activated enzyme. This change precedes phosphoenzyme formation in the catalytic cycle and is greatly accelerated by the adenine moiety of the substrate.

Animals↗
PubMed1990

Existence of a low-affinity ATP-binding site in the unphosphorylated Ca2(+)-ATPase of sarcoplasmic reticulum vesicles: evidence from binding of 2',3'-O-(2,4,6-trinitrocyclohexadienylidene)-[3H]AMP and -[3H]ATP.

ATP-binding sites in the unphosphorylated Ca2(+)-ATPase of sarcoplasmic reticulum vesicles were titrated with 2',3'-O-(2,4,6-trinitrocyclohexadienylidene)-[3H]AMP (TNP-AMP) or -[3H]ATP (TNP-ATP) in the absence of Ca2+ at pH 7.0 and 0 degrees C by using a centrifugation procedure. In some measurements, the bound TNP-nucleotides were chased with ATP. The data were analyzed by best-fit computer programs as well as by Scatchard plots. The results showed the existence of 1 mol of TNP-AMP binding sites with high affinity (Kd = 7.62 nM) per mole of phosphorylatable sites. The affinity of these sites for ATP (Kd = 10.1 microM) agreed with that of catalytic sites for ATP in the absence of Ca2+. The results further showed the existence of 2 mol of TNP-ATP binding sites with uniform affinity (Kd = 156 nM) per mole of phosphorylatable sites. Half of the bound TNP-ATP was fully chased by low concentrations of ATP. The affinity of this class of the sites for ATP (Kd = 8.9 microM) again agreed with that of catalytic sites for ATP. The other half of the bound TNP-ATP was fully chased only by much higher concentrations of ATP. Thus, the affinity of this class of the sites for ATP (Kd = 791 microM) was much lower than that of catalytic sites for ATP. Similar measurements were performed with sarcoplasmic reticulum vesicles pretreated by N-(iodoacetyl)-N'-(5-sulfo-1-naphthyl)ethylenediamine. Although the affinities for TNP-ATP and for ATP were appreciably altered by this pretreatment, the results were essentially the same as those obtained with native vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Monophosphate↗
PubMed1990

Selective inhibition by lasalocid of hydrolysis of the ADP-insensitive phosphoenzyme in the catalytic cycle of sarcoplasmic reticulum Ca2(+)-ATPase.

The effect of a carboxylic ionophore (lasalocid) on the sarcoplasmic reticulum Ca2(+)-ATPase was investigated. The purified enzyme was preincubated with lasalocid in the presence of Ca2+ and the absence of K+ at pH 7.0 and 0 degrees C for 2 h. The Ca2(+)-dependent ATPase activity was strongly inhibited by this preincubation, whereas the activity of the contaminant Mg2(+)-ATPase was unaffected. The steady-state level of the phosphoenzyme (EP) intermediate remained constant over the wide range of lasalocid concentrations. The Ca2(+)-induced enzyme activation was unaffected. The kinetics of phosphorylation of the Ca2(+)-activated enzyme by ATP as well as the rate of conversion of ADP-sensitive EP to ADP-insensitive EP were also unaffected. Accumulation of ADP-insensitive EP was greatly enhanced, and almost all of the EP accumulating at steady state was ADP-insensitive. Hydrolysis of ADP-insensitive EP was strongly inhibited. A similar strong inhibition of the Ca2(+)-dependent ATPase activity by lasalocid was found with sarcoplasmic reticulum vesicles. To examine the effect of lasalocid on the conformational change in each reaction step, the Ca2(+)-ATPase of sarcoplasmic reticulum vesicles was labeled with a fluorescent probe (N-iodoacetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine) without a loss of catalytic activity and then preincubated with lasalocid as described above. The conformational changes involved in hydrolysis of ADP-insensitive EP and in the reversal of this hydrolysis were appreciably retarded by lasalocid. The conformational changes involved in other reaction steps were unaffected. These results demonstrate that hydrolysis of ADP-insensitive EP in the catalytic cycle of this enzyme is selectively inhibited by lasalocid.

Adenosine Diphosphate↗