Cytotoxic action of bisabololoxide A of German chamomile on human leukemia K562 cells in combination with 5-fluorouracil

German chamomile (Matricaria recutita L.) is a popular ingredient in herbal teas. In previous study, micromolar bisabololoxide A, one of main constituents in German chamomile, exerted cytotoxic action on rat thymocyte, a normal non-proliferative cell. This result prompted us to study the effect of bisabololoxide A on proliferative cancer cells and to seek the possibility of its use with 5-fluorouracil, an anticancer agent. In this study, the effect of micromolar bisabololoxide A on human leukemia K562 cells was cytometrically examined. Although the incubation of K562 cells with 10 μM bisabololoxide A for 72h did not significantly increase the percentage populations of dead cells and shrunken cells, the inhibitory action on the growth was obviously observed. It was not the case for the concentrations of less than 5 μM. The threshold concentration of bisabololoxide A to exert the cytotoxic action on K562 cells was ascertained to be 5-10 μM. Bisabololoxide A at 5-10 μM did not exert cytotoxic action on normal non-proliferative cells (rat thymocytes) in our previous study. Since the antiproliferative action of micromolar bisabololoxide A on cancerous cells was expected to be beneficial to cancer treatment, the modification of antiproliferative action of 5-fluorouracil (3-30 μM) by bisabololoxide A was studied. The combination of 5-fluorouracil and bisabololoxide further inhibited the growth of K562 cells although the additive inhibition of growth by bisabololoxide A became smaller as the concentration of 5-fluorouracil increased. Therefore, it is suggested that the simultaneous application of German chamomile containing bisabololoxide A may reduce the dose of 5-fluorouracil.

Identification of cytotoxic dimers in oxidation product from sesamol, a potent antioxidant of sesame oil

Phytophenols of edible plants have recently attracted much attention as potent antioxidants and related bioactive substances. These antioxidative phytophenols are very oxidizable due to their chemical properties, and their oxidation products must accumulate in the oxidizing foods when they are contained as active ingredients. In this investigation, several phytophenols, which are well known as potent antioxidants in food science, were oxidized by oxygen in the presence of a catalytic amount of Ferric ion. Caffeic acid, catechin, chlorogenic acid, rosmarinic acid, and sesamol were quickly oxidized, whereas eugenol, resveratrol, rutin, and quercetin were not under the stated conditions. The oxidation product mixtures of the quickly oxidized phytophenols were next subjected to a cytotoxic assay using normal cells. Among the products, the oxidation product from sesamol showed a remarkably high cytotoxic activity. To clarify the cytotoxic principle of the oxidation products, an assay-guided fractionation and subsequent isolation of the oxidation compound of sesamol was carried out. Structure analysis of the isolated compounds revealed that they are new dimeric compounds (2-5) of sesamol. The cytotoxic activity of the dimers was evaluated from the population of dead cells by a flow cytometric analysis of rat thymocytes in the presence of 100 μM of each compound. Compound 2 showed the most potent cytotoxic activity among them. Compound 2 has a typical conjugated carbonyl moiety and the moiety possibly contributes to its high toxicity from a structure-activity point of view.

Low micromolar zinc exerts cytotoxic action under H2O2-induced oxidative stress: excessive increase in intracellular Zn2+ concentration

The ability of zinc to retard oxidative processes has been recognized for many years. However, zinc is cytotoxic under certain oxidative stress. In this study, we investigated the effect of H2O2 on intracellular Zn2+ concentration of rat thymocytes and its relation to the cytotoxicity. Experiments were cytometrically performed by the use of fluorescent probes, propidium iodide, FluoZin-3-AM, and 5-chloromethylfluorescein diacetate. ZnCl2 potentiated cytotoxicity of H2O2 while TPEN, a chelator for intracellular Zn2+, attenuated it. Results suggested an involvement of intracellular Zn2+ in the cytotoxicity of H2O2. H2O2 at concentrations of 30microM or more (up to 1000microM) significantly increased intracellular Zn2+ concentration. There were two mechanisms. (1) H2O2 decreased cellular content of nonprotein thiols, possibly resulting in release of Zn2+ from thiols as cellular Zn2+ binding sites. (2) H2O2 increased membrane Zn2+ permeability because external ZnCl2 application further elevated intracellular Zn2+ concentration. Micromolar H2O2 may induce excessive elevation of intracellular Zn2+ concentration that is harmful to cellular functions. However, the incubation with micromolar ZnCl2 alone increased cellular content of nonprotein thiols, one of the factors protecting cells against oxidative stress. Though zinc is generally considered to be protective with its antioxidant property, this study reveals the toxic effect of zinc even in micromolar range under oxidative stress induced by H2O2.

Tri-n-butyltin increases intracellular Zn(2+) concentration by decreasing cellular thiol content in rat thymocytes

Effect of tri-n-butyltin (TBT), an environmental pollutant, on intracellular Zn(2+) concentration was tested in rat thymocytes to reveal one of cytotoxic profiles of TBT at nanomolar concentrations using a flow cytometer and appropriate fluorescent probes. TBT at concentrations of 30 nM or more (up to 300 nM) significantly increased the intensity of FluoZin-3 fluorescence, an indicator for intracellular Zn(2+) concentration, under external Ca(2+)- and Zn(2+)-free condition. Chelating intracellular Zn(2+) completely attenuated the TBT-induced augmentation of FluoZin-3 fluorescence. Result suggests that nanomolar TBT releases Zn(2+) from intracellular store site. Oxidative stress induced by hydrogen peroxide also increased the FluoZin-3 fluorescence intensity. The effects of TBT and hydrogen peroxide on the fluorescence were additive. TBT-induced changes in the fluorescence of FluoZin-3 and 5-chloromethylfluorescein, an indicator for cellular thiol content, were correlated with a coefficient of -0.962. Result suggests that the intracellular Zn(2+) release by TBT is associated with TBT-induced reduction of cellular thiol content. However, chelating intracellular Zn(2+) potentiated the cytotoxicity of TBT. Therefore, the TBT-induced increase in intracellular Zn(2+) concentration may be a type of stress responses to protect the cells.

Search for proton decay via p-->e+pi0 and p-->micro+pi0 in a large water Cherenkov detector

We have searched for proton decays via p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} using data from a 91.7 kt.yr exposure of Super-Kamiokande-I and a 49.2 kt.yr exposure of Super-Kamiokande-II. No candidate events were observed with expected backgrounds induced by atmospheric neutrinos of 0.3 events for each decay mode. From these results, we set lower limits on the partial lifetime of 8.2 x 10;{33} and 6.6 x 10;{33} years at 90% confidence level for p-->e;{+}pi;{0} and p-->micro;{+}pi;{0} modes, respectively.

WITHDRAWN: P.P.2 04 Chronological observation of glucose intolerance in myotonic dystrophy

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Cytometric analysis of cytotoxicity of polyphenols and related phenolics to rat thymocytes: potent cytotoxicity of resveratrol to normal cells

The chemopreventive and chemotherapeutic actions of polyphenols and related phenolics have received considerable attention since these compounds induce apoptosis in several types of cancer cells in vitro. A plausible criterion for the use of such compounds is that they should not exert any toxic effect on normal cells. However, information about the toxicity of polyphenols and related phenolics to normal cells is limited. In this study, the effects of polyphenols and related phenolics on rat thymocytes were examined by flow cytometric analysis with appropriate fluorescent probes. The compounds examined in this study were caffeic acid, rosmarinic acid, chlorogenic acid, (+)-catechin, 6-gingerol, sesamol, resveratrol, and eugenol. Of these, resveratrol was the most cytotoxic on rat thymocytes incubated for 24 hrs with 100 microM of this compound. Resveratrol at a concentration of 10 microM or more (up to 100 microM) led to a significant dose-dependent increase in the population of dead cells, shrunken living cells, annexin V-positive cells and cells with hypodiploidal DNA. In the presence of benzyloxycarbonyl-Val-Ala-Asp (OMe) fluoromethylketone (Z-VAD-FMK), a pan-inhibitor of caspases, the resveratrol-induced increase in the population of cells with hypodiploidal DNA was partially inhibited. Overall, it is suggested that resveratrol at a concentration of 10 microM or more induces apoptosis in normal cells as well as cancer cells (previously reported elsewhere). Thus, at concentrations that are suitable for chemopreventive and chemotherapeutic actions, resveratrol may exert a cytotoxic effect on normal cells.

Tachycardia-dependent right bundle-branch block with supernormal conduction

This paper reports the case of a 76-year-old man in whom atrial flutter with varying atrioventricular block and intermittent right bundle-branch block was found. This is the first report on tachycardia-dependent right bundle-branch block associated with supernormal conduction in a case of atrial flutter. When an impulse is conducted to the ventricles beyond 0.72 s after a QRS complex of right bundle-branch block configuration, the impulse falls after the abnormally long effective refractor period of the right bundle branch and passes through the right bundle branch. When the conducted impulse occurs within 0.72 s after a QRS complex of right bundle-branch block configuration, the impulse usually falls in the refractory period and is blocked in the right bundle branch; however, only when the impulse occurs 0.48 or 0.49 s after that does it fall in the supernormal period and passes through the right bundle branch. The findings in the present report strengthen our previous suggestion that the presence of supernormal conduction plays an important role in the initiation of reentrant ventricular tachycardia.

Clotrimazole, an antifungal drug possessing diverse actions, increases membrane permeation of cadmium in rat thymocytes

In previous study, clotrimazole, an antifungal drug, exerted potent cytotoxic action on rat thymocytes in presence of metal divalent cations such as Cd(2+) and Pb(2+). To reveal one of toxicological characteristics of clotrimazole, we examined the effect of clotrimazole on intracellular concentration of metal divalent cations by flow cytometer with fluo-3, a fluorescent. Simultaneous application of clotrimazole and CdCl(2) significantly decreased the cell viability although their concentrations were not cytotoxic, respectively. Clotrimazole alone increased the intensity of fluo-3 fluorescence, suggesting an increased concentration of intracellular Ca(2+). The intensity of fluo-3 fluorescence augmented by the combination of clotrimazole and CdCl(2) was much higher than that by respective agents. Removal of external Ca(2+) further increased the intensity of fluorescence augmented by the combination. Furthermore, the application of MnCl(2) did not attenuate the intensity in the presence of CdCl(2). Therefore, it is suggested that the augmentation of fluo-3 fluorescence in the simultaneous presence of clotrimazole and CdCl(2) is Cd(2+)-dependent. Clotrimazole may increase membrane permeation of Cd(2+).

Autologous non-myeloablative haematopoietic stem cell transplantation for refractory systemic vasculitis

OBJECTIVE

For patients with systemic vasculitis (SV) refractory to conventional therapy, new treatment strategies aimed at aggressive induction of remission and relapse prevention are being sought. We herein report our single-centre experience in treating four patients with refractory SV employing non-myeloablative autologous haematopoietic stem cell transplantation (HSCT).

METHODS

Four patients with refractory SV (two with neurovascular Behcet disease, one with neurovascular Sjögren syndrome, and one with Wegener granulomatosis) were involved in an Institutional Review Board (IRB) and US Food and Drug Administration (FDA) approved phase I clinical trial of high dose chemotherapy and autologous HSCT. Peripheral blood stem cells were mobilised with cyclophosphamide (Cy) and granulocyte-colony stimulating factor (G-CSF). Conditioning regimen consisted of Cy 200 mg/kg and rabbit anti-thymocyte globulin 5.5 mg/kg intravenously (iv).

RESULTS

All four patients tolerated HSCT well without transplant related mortality or any significant toxicity. At median follow-up of 28 (range 22-36) months all patients were alive. Three patients (one with Behcet disease, one with Sjögren syndrome, and one with Wegener granulomatosis) entered a sustained remission at 6, 6 and 24 months, respectively, after transplant. They had significant decrease in disease activity and disease or treatment related damage, as measured by the Birmingham Vasculitis Activity Score and Vasculitis Damage Index, respectively. All three patients who achieved remission discontinued immunosuppressive therapy at the time of transplant and have not required treatment since. One patient with Behcet disease and positive for human leukocyte antigen (HLA)-B51 has not improved after HSCT.

CONCLUSION

We suggest non-myeloablative autologous HSCT is an alternative therapy for select patients with SV refractory to conventional immunosuppressive therapies.

Autologous non-myeloablative hematopoietic stem cell transplantation in patients with systemic sclerosis

Autologous hematopoietic stem cell transplantation (HSCT) utilizing a myeloablative regimen containing total body irradiation has been performed in patients with systemic sclerosis (SSc), but with substantial toxicity. We, therefore, conducted a phase I non-myeloablative autologous HSCT study in 10 patients with SSc and poor prognostic features. PBSC were mobilized with CY and G-CSF. The PBSC graft was cryopreserved without manipulation and re-infused after the patient was treated with a non-myeloablative conditioning regimen of 200 mg/kg CY and 7.5 mg/kg rabbit antithymocyte globulin. There was a statistically significant improvement of modified Rodnan skin score whereas cardiac (ejection fraction, pulmonary arterial pressure), pulmonary function (DLCO) and renal function (creatinine) remained stable without significant change. One patient with advanced disease died 2 years after the transplant from progressive disease. After median follow-up of 25.5 months, the overall and progression-free survival rates are 90 and 70% respectively. Autologous HSCT utilizing a non-myeloablative conditioning regimen appears to result in improved skin flexibility similar to a myeloablative TBI containing regimen, but without the toxicity and risks associated with TBI.

Synergic cytotoxic action induced by simultaneous application of zinc and clotrimazole in rat thymocytes

In our previous study, the application of clotrimazole, an antifungal drug, with CdCl(2) or PbCl(2) significantly increased cell lethality of rat thymocytes, even though their individual concentrations were ineffective in affecting the viability. This observation prompted us to study the case for the combination of clotrimazole and ZnCl(2) because the use of zinc as a nutritional supplement has become common. Their combination induced very potent cytotoxic action on rat thymocytes with "bell-shape" dose-response relation. An acceleration of apoptotic process by the combination was suggested for the mechanism. The present result may provide a new insight into toxicological characteristics of clotrimazole.

A phase I/II study of an antitumor vaccination using α (1,3) galactosyltransferase expressing allogeneic tumor cells in pancreatic cancer

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Background: Prognosis of pancreatic cancer remains poor despite surgical resection. In a phase I trial, we examined the safety and feasibility of antitumor vaccination in Pts with surgically resected pancreatic cancer with two irradiated genetically altered human pancreatic cancer cell lines engineered to express xenotransplantation antigens by retroviral transfer of the murine a(1,3) galactosyltrasferase gene {HyperAcute Pancreatic Cancer Vaccine (HAPa)}. Methods: Pts had undergone complete surgical resection for stage IA to IIB pancreatic adenocarcinoma, ECOG PS≤2, no immunosuppressive drug use and an adequate organ function were eligible. Various adjuvant treatments were allowed prior to the start of HAPa according to the institutional preferences (5FU/radiation, cisplatin/gemicitabine followed by 5FU/radiation, 5FU/radiation followed by gemicitabine or gemicitabine/capecitabine/bevasizumab/radiation). Six Pts were scheduled to receive 12 every two week-intradermal injections (initial priming dose followed by 11 boost doses). The first cohort (Pts 1–3) was to receive at lower doses (2 × 108 cells priming and 1 x 108 cells boost). The second cohort (Pts 4–6) was to receive at higher doses (5 x 10^8 cells priming and 3 x 10^8 cells boost). Toxicity was assessed using the CTC v3.0. Results: To date, 6 Pts, 3 males, 3 females, median age 59 (range 50–66) were treated. Two Pts completed all 12 injections. Others received 9, 6, 6 and 4 injections, respectively. To date no serious adverse events can be attributed to the vaccine. Adverse events (≤CTC grade 2) attributable to the vaccine include injection site pain/discomfort and local skin reaction in all Pts. Other adverse events (≤grade 2) include hyperkalemia, fever and increased LDH levels in one Pt. One Pt with non-malignant hepatic lesions at the time of initial surgery was removed from the study after confirmation of metastatic disease in the liver. At this point the median 6.5 (range 9–4) months in the study all remaining (5/6) patients have no evidence of recurrent disease. Conclusions: Preliminary data indicate that antitumor vaccination with genetically altered allogeneic human pancreatic cancer cells expressing a(1, 3) galactosyltrasferase is safe and feasible

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