Ebi3 knockout aggravates experimental periodontitis via Th17 polarization

AIM

To investigate the role of Ebi3-related cytokines (i.e., interleukin [IL]-35 and/or IL-27) in experimental periodontitis using Ebi3 knockout (KO) mice.

MATERIALS AND METHODS

The maxillary right second molar teeth of Ebi3 KO mice and C57BL/6 mice were tied with a silk ligature to induce periodontitis. Three days after ligation, gingival tissues were collected for gene expression analyses. Five days after ligation, the maxillae were removed for haematoxylin and eosin staining and immunohistochemistry. Seven days after ligation, the maxillae were removed for micro-computed tomography.

RESULTS

The ligated side of Ebi3 KO mice showed intense alveolar bone resorption, which was substantially more pronounced than in wild-type (WT) mice. IL-17A expression was significantly higher in the gingiva of the ligated side of Ebi3 KO mice compared with WT mice. IL-10 expression was significantly lower in Ebi3 KO mice than in WT mice. The ligature-induced alveolar bone resorption in Ebi3 KO mice that received recombinant IL-35 injection was significantly less compared with that in Ebi3 KO mice that received control injection.

CONCLUSIONS

Together, these findings suggest that Th17 cells exacerbate experimental periodontitis in mice lacking Ebi3 and that IL-35 may play a critical role in inhibiting periodontal tissue destruction.

Porphyromonas gingivalis Fimbriae Induce Osteoclastogenesis via Toll-like Receptors in RAW264 Cells

The effect of Mfa1 fimbriae of Porphyromonas gingivalis on the progression of bone resorption remains unclear, especially compared with another fimbriae, FimA. We investigated the effect of Mfa1 on osteoclastogenesis together with FimA. We also investigated the role of Toll-like receptors (TLRs) in Mfa1 recognition during osteoclast differentiation. Receptor activator of nuclear factor κβ ligand (RANKL)-prestimulated RAW264 cells were used to examine the effects of purified Mfa1 fimbriae. The number of osteoclasts was examined by tartrate-resistant acid phosphate (TRAP) staining, osteoclast activation was investigated by bone resorption assays, and gene expression of differentiation markers was examined by quantitative real-time PCR. Transfection of Tlr2 and Tlr4 siRNAs into RAW264 cells was also employed and their role in Mfa1 recognition was investigated. Mfa1 effectively induced the formation of TRAP-positive multinucleated cells and activated osteoclasts. Mfa1 also increased gene expression of Acp5, Mmp9, and Ctsk in RANKL-prestimulated RAW264 cells compared with the control. The osteoclastogenesis induced by Mfa1 was significantly decreased in cells transfected with Tlr2 or Tlr4 siRNAs compared with control siRNA. Our results revealed the role of Mfa1 fimbriae in osteoclastogenesis that may contribute to the partial elucidation of the mechanisms of periodontal disease progression and the development of new therapeutic strategies.

O-015 Results of urological consultation in the setting of IVF clinic

Study question

In the management of male infertility, we investigated whether urological consultation could improve the live birth rate, and who should visit urologists in the setting of IVF clinic.

Summary answer

Urologic consultation resulted in improvement of semen quality and live birth rate with more IVF use in those with adverse semen parameters.

What is known already

Male factor infertility exists in about a half of infertility couples. This accounts for about 8% in male reproductive age. Therefore, ideally every male partner of infertility couples attempting conception should have a urological evaluation. However, it is not very easy to access urologists who specialized in reproductive medicine in Japan because we have very few of such urologists. One the other hand, a certain number of couples are wasting their time during IVF failure without urological evaluation.

Study design, size, duration

This is a single-institution retrospective study. We enrolled male partners of infertility couples who visited Kameda IVF clinic Makuhari, Chiba, Japan, between May 2016 and December 2020 and followed at least one year. Live birth rate and the frequency of IVF use were investigated according to semen quality and urological consultation status. Chi-square tests and T tests were used to compare the results between groups.

Participants/materials, setting, methods

Among 2225 couples who visited Kameda IVF clinic Makuhari, 803 male partners (Group A, 36.0%) were evaluated by urologists who were specialized in male reproductive medicine. Remaining 1422 patients did not (Group B, 64.0%). Lifestyle evaluation, physical examination, semen analyses, scrotal ultrasonography, blood test including sexual hormones and zinc concentration were performed in Group A. Semen analyses and lifestyle evaluation were performed in Group B. Urological treatments were done according to factors of male infertility.

Main results and the role of chance

Semen quality was worse in Group A as compared to Group B (sperm motility, 28.5±16.9% vs. 46.0±17.0%; total sperm count, 105±108 million/mL vs. 176±155; total motile sperm count, 34±49 vs.87±98; mean±S.D.; p = 0.0001, 0.0001, 0.0001, A vs. B, respectively). After urologic consultation and managements, sperm motility was improved to 34±18% (p = 0.001). Live birth rate in groups A and B were similar (56.0% vs. 57.2%), however couples who obtained a child in Group A used IVF more often than those in Group B (70% vs. 49.9%, p < 0.001). Among those with adverse semen quality (total motile sperm count less than 15.6 million/mL, n = 472), 350 visited urologists (Group 1, 74.2%) and remaining 122 did not (Group 2, 25.8%). Live birth rate in Group 1 was significantly better than in Group 2 (65.3% vs. 54.1%, p = 0.0359). Use of IVF was significantly more frequent in Group 1 than Group 2 (79.3% vs. 63.6%, p = 0.0359) among who obtained a child. In those with better semen quality (motile sperm count >50 million, n = 900), 119 visited urologist (31.1%, Group 3) and 781 did not (Group 4). Live birth rate and the use of IVF were not different between Groups 3 and 4 (51.1% vs.60.9%; 50.4% vs. 62.9%).

Limitations, reasons for caution

This study is a single-institution, retrospective study in the setting of IVF clinic. There may be a selection bias since men first visit gynecologists. These could affect the study results.

Wider implications of the findings

In the setting of IVF clinic, urologic consultation resulted in improved semen quality and better live birth rate with the use of IVF, especially in those who have adverse semen parameters. The results of this study encourage patients to see urologists and physicians to introduce urologist to patients.

Trial registration number

not applicable

Porphyromonas gingivalis Components/Secretions Synergistically Enhance Pneumonia Caused by Streptococcus pneumoniae in Mice

Streptococcus pneumoniae is an important causative organism of respiratory tract infections. Although periodontal bacteria have been shown to influence respiratory infections such as aspiration pneumonia, the synergistic effect of S. pneumoniae and Porphyromonas gingivalis, a periodontopathic bacterium, on pneumococcal infections is unclear. To investigate whether P. gingivalis accelerates pneumococcal infections, we tested the effects of inoculating P. gingivalis culture supernatant (PgSup) into S. pneumoniae-infected mice. Mice were intratracheally injected with S. pneumoniae and PgSup to induce pneumonia, and lung histopathological sections and the absolute number and frequency of neutrophils and macrophages in the lung were analyzed. Proinflammatory cytokine/chemokine expression was examined by qPCR and ELISA. Inflammatory cell infiltration was observed in S. pneumoniae-infected mice and S. pnemoniae and PgSup mixed-infected mice, and mixed-infected mice showed more pronounced inflammation in lung. The ratios of monocytes/macrophages and neutrophils were not significantly different between the lungs of S. pneumoniae-infected mice and those of mixed-infected mice. PgSup synergistically increased TNF-α expression/production and IL-17 production compared with S. pneumoniae infection alone. We demonstrated that PgSup enhanced inflammation in pneumonia caused by S. pneumoniae, suggesting that virulence factors produced by P. gingivalis are involved in the exacerbation of respiratory tract infections such as aspiration pneumonia.

IL-35 and RANKL Synergistically Induce Osteoclastogenesis in RAW264 Mouse Monocytic Cells

Interleukin (IL)-35 is an immunosuppressive cytokine mainly produced by regulatory T cells. IL-35 mediates immunological functions by suppressing the inflammatory immune response. However, the role of IL-35 in bone-destructive diseases remains unclear, especially in terms of osteoclastogenesis. Therefore, the current study investigated the synergistic effect of IL-35 on osteoclastogenesis that is involved the pathogeneses of periodontitis and rheumatoid arthritis. Osteoclastic differentiation and osteoclastogenesis of RAW264 (RAW) cells induced by receptor activator of nuclear factor (NF)-κB ligand (RANKL) and IL-35 were evaluated by tartrate-resistant acid phosphate staining, hydroxyapatite resorption assays, and quantitative polymerase chain reaction. The effect of IL-35 on RANKL-stimulated signaling pathways was assessed by Western blot analysis. Costimulation of RAW cells by RANKL and IL-35 induced osteoclastogenesis significantly compared with stimulation by RANKL alone. Phosphorylations of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase tended to be increased by RANKL and IL-35 compared with RANKL or IL-35 alone. Additionally, the osteoclastogenesis induced by RANKL and IL-35 was suppressed by inhibition of ERK. In this study, IL-35 and RANKL induced osteoclastogenesis synergistically. Previous reports have shown that IL-35 suppresses the differentiation of osteoclasts. Therefore, IL-35 might play dual roles of destruction and protection in osteoclastogenesis.

Molecular signatures associated with cognitive deficits in schizophrenia: a study of biopsied olfactory neural epithelium

Cognitive impairment is a key feature of schizophrenia (SZ) and determines functional outcome. Nonetheless, molecular signatures in neuronal tissues that associate with deficits are not well understood. We conducted nasal biopsy to obtain olfactory epithelium from patients with SZ and control subjects. The neural layers from the biopsied epithelium were enriched by laser-captured microdissection. We then performed an unbiased microarray expression study and implemented a systematic neuropsychological assessment on the same participants. The differentially regulated genes in SZ were further filtered based on correlation with neuropsychological traits. This strategy identified the SMAD 5 gene, and real-time quantitative PCR analysis also supports downregulation of the SMAD pathway in SZ. The SMAD pathway has been important in multiple tissues, including the role for neurodevelopment and bone formation. Here the involvement of the pathway in adult brain function is suggested. This exploratory study establishes a strategy to better identify neuronal molecular signatures that are potentially associated with mental illness and cognitive deficits. We propose that the SMAD pathway may be a novel target in addressing cognitive deficit of SZ in future studies.

Superconducting pairing and the pseudogap in the nematic dynamical stripe phase of La2-xSrxCuO4

Fully absorption coefficient corrected Raman spectra were obtained in La2-xSrxCuO4. The B1g spectra have a Fleury-Loudon type two-magnon peak (resonant term) whose energy decreases from 3180 cm(-1) (394 meV) to 440 cm(-1) (55 meV) on increasing the carrier density from x = 0 to 0.25, while the B2g spectra have a 1000-3500 cm(-1) (124-434 meV) hump (hill) whose lower-edge energy increases from x = 0 to 0.115 and then stays constant to x = 0.25. The B2g hump is assigned to the electronic scattering (non-resonant term) of the spectral function with magnetic self-energy. The completely different carrier density dependence arises from anisotropic magnetic excitations of spin-charge stripes. The B1g spectra were assigned to the sum of k ∥  and k⊥ stripe excitations and the B2g spectra to k⊥ stripe excitations according to the calculation by Seibold and Lorenzana (2006 Phys. Rev. B 73 144515). The k ∥  and k⊥ stripe excitations in fluctuating spin-charge stripes were separately detected for the first time. The appearance of only k⊥ stripe excitations in the electronic scattering arises from the charge hopping perpendicular to the stripe. This is the same direction as the Burgers vector of the edge dislocation in metal. The successive charge hopping in the Burgers vector direction across the charge stripes may cause Cooper pairs as predicted by Zaanen et al (2004 Ann. Phys. 310 181). Indeed, this is supported by the experimental fact that the superconducting coherent length coincides with the inter-charge stripe distance in the wide carrier density range. The one-directional charge hopping perpendicular to the stripe causes the flat Fermi surface and the pseudogap near (π,0) and (0,π), but the states around (π/2,π/2) cannot be produced. The low-energy Raman scattering disclosed that the electronic states at the Fermi arc around (π/2,π/2) are coupled to the A1g soft phonon of the tetragonal-orthorhombic phase transition. This suggests that the Fermi arc is produced by the electron-phonon interaction. All the present Raman data suggest that Cooper pairs are formed at moving edge dislocations of dynamical charge stripes.

Correlation between Raman sum and optical conductivity sum in La(2-x)Sr(x)CuO4

In a strongly correlated electron system, the single-particle spectral function changes into a coherent peak and incoherent humps which extend over 1 eV. The incoherent parts lose the symmetry and k dependence, so that the Raman spectra with different symmetries become identical and they are expressed by the optical conductivity. We found that the B1g and B2g spectra in La(2-x)Sr(x)CuO4 become identical above 2000 cm(-1) in the underdoped phase, if Fleury-Loudon type B1g two-magnon scattering is removed. The first Raman susceptibility moment correlates with the generalized optical conductivity moment. The good correlation arises from the incoherent states of a hump from 1000 to 4000 cm(-1). The hump is the only structure of the incoherent electronic states in the mid-infrared absorption spectra below 1.4 eV at low carrier densities. The energy is twice the separated dispersion segments of the spin wave in the k(perpendicular) stripe direction. The incoherent state is formed by the magnetic excitations created by the hole hopping in the antiferromagnetic spin stripes in the real space picture.

Catalytic lectin (leczyme) from bullfrog (Rana catesbeiana) eggs

Catalytic lectins (leczymes) of frog eggs are sialic acid-binding lectins that have intrinsic RNase activity. They inhibit tumor cell proliferation in vitro and in vivo, although their cytotoxic mechanism remains unclear. RNase A has no tumoricidal activity. It is hypothesized that leczymes bind to cell surface sialoglycoconjugate receptors, enter the cell, and subsequently degrade RNA. In order to investigate the cytotoxic mechanism of cSBL, a leczyme from Rana catesbeiana eggs, we established cSBL-resistant clone RC-150 from mouse leukemia P388 cells. cSBL-treated P388 cells showed extensive RNA degradation over the course of 1 h, whereas cSBL-treated RC-150 cells showed no RNA degradation even over the course of 24 h. Treatment of P388 cells with cSBL led to decreased concentration of intracellular Ca2+, decreased protein kinase A activity, and increased protein kinase G activity. Incubation with cSBL decreased glutathione levels and enhanced glutathione-S-transferase (GST) activity in P388 cells, but had no effect on RC-150 cells. We conclude that cSBL-specific degradation of RNA occurs in cSBL-sensitive tumor cells, that cSBL leads to alteration of signal transduction and an intracellular protein kinase cascade reaction, and that internalized cSBL is detoxified by GST or thioltransferase. Our findings support a bifunctional model in which a leczyme is both an adhesive protein (binding to sialoglycoconjugates) and an enzyme (displaying RNnase activity).

Involvement of prolactin-releasing peptide in the activation of oxytocin neurones in response to food intake

Food intake activates neurones expressing prolactin-releasing peptide (PrRP) in the medulla oblongata and oxytocin neurones in the hypothalamus. Both PrRP and oxytocin have been shown to have an anorexic action. In the present study, we investigated whether the activation of oxytocin neurones following food intake is mediated by PrRP. We first examined the expression of PrRP receptors (also known as GPR10) in rats. Immunoreactivity of PrRP receptors was observed in oxytocin neurones and in vasopressin neurones in the paraventricular and supraoptic nuclei of the hypothalamus and in the bed nucleus of the stria terminalis. Application of PrRP to isolated supraoptic nuclei facilitated the release of oxytocin and vasopressin. In mice, re-feeding increased the expression of Fos protein in oxytocin neurones of the hypothalamus and bed nucleus of the stria terminalis. The increased expression of Fos protein in oxytocin neurones following re-feeding or i.p. administration of cholecystokinin octapeptide (CCK), a peripheral satiety factor, was impaired in PrRP-deficient mice. CCK-induced oxytocin increase in plasma was also impaired in PrRP-deficient mice. Furthermore, oxytocin receptor-deficient mice showed an increased meal size, as reported in PrRP-deficient mice and in CCKA receptor-deficient mice. These findings suggest that PrRP mediates, at least in part, the activation of oxytocin neurones in response to food intake, and that the CCK-PrRP-oxytocin pathway plays an important role in the control of the termination of each meal.

Roles of oxytocin neurones in the control of stress, energy metabolism, and social behaviour

Oxytocin neurones are activated by stressful stimuli, food intake and social attachment. Activation of oxytocin neurones in response to stressful stimuli or food intake is mediated, at least in part, by noradrenaline/prolactin-releasing peptide (PrRP) neurones in the nucleus tractus solitarius, whereas oxytocin neurones are activated after social stimuli via medial amygdala neurones. Activation of oxytocin neurones induces the release of oxytocin not only from their axon terminals, but also from their dendrites. Oxytocin acts locally where released or diffuses and acts on remote oxytocin receptors widely distributed within the brain, resulting in anxiolytic, anorexic and pro-social actions. The action sites of oxytocin appear to be multiple. Oxytocin shows anxiolytic actions, at least in part, via serotoninergic neurones in the median raphe nucleus, has anorexic actions via pro-opiomelanocortin neurones in the nucleus tractus solitarius and facilitates social recognition via the medial amygdala. Stress, obesity and social isolation are major risk factors for mortality in humans. Thus, the oxytocin-oxytocin receptor system is a therapeutic target for the promotion of human health.

Phason and amplitudon in the charge-density-wave phase of one-dimensional charge stripes in La(2-x)Sr(x)CuO4

The present systematic Raman scattering experiments reveal the phason and amplitudon of the charge density wave (CDW) mode in the charge stripes of La(2-x)Sr(x)CuO4. Only about 15% of the electronic density of states condenses into the CDW state. The symmetries of the CDW modes change by the rotation of the stripes at the insulator-metal transition. The energy of the phason is finite at 0.06 < or = x < or = 0.1 and zero at x = 0.035 and 0.115 < or = x < or = 0.135, which suggests that the CDW is commensurate at 0.06 < or = x < or = 0.1 and incommensurate otherwise. The zero-energy phason seems to reduce T(c) at x = 1/8.

Effect of modification of the carboxyl groups of the sialic acid binding lectin from bullfrog (Rana catesbeiana) oocyte on anti-tumor activity

The sialic acid binding lectin from bullfrog Rana catesbeiana oocyte (cSBL) is known to have anti-tumor activity. In order to investigate the relationship between the net charge of cSBL and its anti-tumor effect, cSBL was modified with a water-soluble carbodiimide (EDC) in the presence of three kinds of nucleophiles, taurine, glycine methylester and ethylenediamine. cSBL having four carboxyl groups was partially modified (ca. 2 residues). The anti-tumor activity of modified cSBLs was in the order of ethylenediamine-modified cSBL > glycine methylester-modified cSBL > taurine modified cSBL > or = native cSBL. The results suggested that anti-tumor activity seems to increase with the increase in positive net charge, possibly enhancing the interaction of cSBL with sialoglycoprotein on the surface of tumor cells. The ribonuclease activity of ethylenediamine-modified cSBL decreased with the progress of the reaction, but the number of internalized molecules in the tumor cell increased. Thus, for antitumor activity, a higher incorporation of cSBL with reasonable RNase activity seems to be more important than total RNase activity.

Reversal of vinblastine resistance in human leukemic cells by haloperidol and dihydrohaloperidol

Haloperidol, an antipsychotic, was investigated in cells overexpressing P-glycoprotein to detemine whether it was a clinically effective drug to reverse for reversing multidrug resistance (MDR) mediated by P-glycoprotein. A nontoxic concentration of haloperidol (1-30 microM) enhanced the cytotoxic effects of vinblastine (VBL) concentration-dependently in VBL-resistant human leukemia (K562/VBL) cells, but had no effect in the parent cells. Haloperidol also enhanced the cytotoxicities of epirubicin, doxorubicin and actinomycin D in the K562/VBL cells, but not those of idarubicin or cisplatin; this enhancement was less than that of the VBL toxicity in the VBL-resistant tumor line. Haloperidol increased the intracellular accumulation of VBL in the K562/VBL cells, and the binding of [3H]-azidopine to the cell-surface protein, P-glycoprotein, was inhibited by haloperidol in a concentration-dependent manner. Haloperidol was less potent than verapamil. Thus, haloperidol appeared to potentiate anticancer agents through the reversal of MDR by competitively inhibiting drug-binding to P-glycoprotein. In contrast, the main metabolite of haloperidol, dihydrohaloperidol, without antipsychotic activity, had less of an effect. Therefore, haloperidol might be useful in reversing drug-resistance.

Mechanism of resistance to oxidative stress in doxorubicin resistant cells

Doxorubicin (DOX) is an anthracycline drug widely used in chemotherapy for cancer patients, but it often gives rise to multidrug resistance in cancer cells. The purpose of this work was to study the effect of hydrogen peroxide in DOX-sensitive mouse P388/S leukemia cells and in the DOX-resistant cell line. Hydrogen peroxide induced a significant increase in dose- and time-response cell death in cultured P388/S cells. The degree of cell death in P388/DOX cells induced by hydrogen peroxide was less than that in P388/S cells treated with hydrogen peroxide. Parent cells exposed to 3 mM of hydrogen peroxide showed a loss of mitochondrial membrane potential correlated with cell death. Hydrogen peroxide at a concentration greater than 0.3 mM increased the intracellular Ca2+ of P388/S cells dose-dependently; however, no change following addition of hydrogen peroxide (0.3-1 mM) was observed in the resistant cells. Hydrogen peroxide (0.1 and 1 mM) treatment also induced the production of intracellular ROS in P388/S cells, while no such increase was produced by this substance in P388/DOX cells. Resistant cells also showed a significant level of glutathione (GSH) compared with the parent cells. In addition, N-acetyl-L-cysteine and reduced GSH antioxidants abolished death of P388/S cells caused by hydrogen peroxide. Therefore, it is believed that the reduced effect of oxidative stress towards the resistant cells may be related to an increase in intracellular GSH level.

[Survey of consciousness of community residents regarding the community life of disabled persons with service dogs]

PURPOSE

Service dogs have received much attention as effective choices for promoting participation in society of disabled persons. The purpose of this study was to obtain the fundamental data to prepare guidelines regarding service dogs use in community life, by making clear the problems in terms of public health and community welfare through a survey of attitudes towards service dogs in community residents.

METHODS

Study 1 was conducted as follows. The subjects were 423 community residents between their teens and seventies who participated in health and welfare lectures in 4 metropolitan areas. A questionnaire survey was conducted just after watching a promotion video about service dogs, including several items on aspects not accept, were anxious about or were unpleasant in the case of community life of a disabled person and a service dog. Study 2 was as follows. A questionnaire survey was conducted inside a supermarket in the central part of Tokyo. One group of subjects were 103 shopping customers who witnessed a shopping scene featuring a disabled person with her service dog, and the other subjects were 84 customers who were not witnessed to the scene. The same survey was simultaneously performed for impression about the shopping scene.

RESULTS

Study 1 showed that 31.8% of all the respondents replied that they had some knowledge of service dogs before watching the video. A total of 20.4% (32.5% of the elderly) replied that there were places where service dogs should not enter. Concretely speaking, these included restaurants for 7.3-22.5% and medical institutions for 8.5-12.5% of the respondents. A third of all the respondents (51.3% of older persons) replied they could not endure some actions by service dogs, concretely "carrying food in the mouth" was highly pointed out by 27.3%. Zoonosis (15.3-19.0%), hair scattering (9.5-21.3%), injuries (4.4-7.4%) were also pointed out as main sources of anxiety or uncomfortable feelings. Such negative opinions were especially apparent among those aged 60 years and older. Also, 44.1% knew some disabled person. Cross tabulation showed those who had experience of taking care of a dog were significant less anxious about "vague anxiety or discomfort," and "zoonosis" than those who had not (P < 0.01). On the other hand, most of both witness (79.6%), and non-witness groups (81.0%) replied that it was heartwarming that the service dog assisted with shopping. None expressed discomfort about the presence of "service dog" inside the supermarket. In terms of carrying a commodity in the mouth, 92.2% and 89.1% in both groups replied that they don't mind, especially if safety was guaranteed for public health, and 91.3% and 95.2% in both groups replied that they had no other problems. Moreover, none of them would not entering stores. Significant differences were seldom in replies between the witness and non-witness groups.

CONCLUSION

Although the respondents were extremely affirmative regarding the image of service dogs, it became clear that anxiety about public health aspects such as "zoonosis" or "utilization of medical institutions" was persisting. On the whole, negative opinions were more apparent in the elderly.

Effects of N(G)-nitro-L-arginine methyl ester on endotoxin-induced leakage of lactate dehydrogenase and cytotoxicity in J774A.1 cells

In the present study, we investigated the effects of the nitric oxide (NO) synthase inhibitor N(G)-nitro-L-arginine-methyl ester (L-NAME) on tissue injury or cytotoxicity caused by endotoxin challenge by assaying lactate dehydrogenase (LDH) isozymes and cell viability in J774A.1 cells. In mice treated with L-NAME (10 mg kg(-1), i.v.), the activity of LDH in serum 18 h after endotoxin (6 mg kg(-1), i.p.) injection was not significantly different from that in mice treated with endotoxin alone. Mice injected with endotoxin exhibited leakage of LDH isozymes 3 and 5, but L-NAME did not protect against endotoxin-induced acute leakage of LDH isozymes. Treatment with L-NAME (10-1000 microM) significantly inhibited NO generation by endotoxin (1 microg ml(-1))-activated J774A.1 cells. However, L-NAME (10-1000 microM) did not affect endotoxin-induced cytotoxicity in J774A.1 cells. These findings suggested that endotoxin-induced NO formation may not contribute to tissue injury or cytotoxicity caused by endotoxin.

Roles of selenium in endotoxin-induced lipid peroxidation in the rats liver and in nitric oxide production in J774A.1 cells

We examined the role of selenium (Se) in the mechanism of oxidative stress caused by endotoxin by feeding rats deficient a diet in this element. In rats fed the Se-deficient diet (concentration of Se, less than 0.027 microg g(-1)) for 10 weeks, Se level and glutathione peroxidase (GSH-Px) activity in the liver were about 47 and 43% lower, respectively, than those in rats fed a Se-adequate diet (Se, 0.2 microg g(-1)). Rat fed the Se-deficient diet and given endotoxin (6 mg kg(-1), i.p.) showed a mortality rates of about 43% at 18 h. Nevertheless, no lethality was observed with endotoxin (4 mg kg(-1), i.p.) challenge. Levels of serum lactate dehydrogenase and acid phosphatase leakage were significantly higher in Se-deficient rats than those in Se-adequate diet 18 h after endotoxin (4 mg kg(-1), i. p.) challenge. Superoxide anion generation and lipid peroxide formation in the liver of Se-deficient rat were markedly increased 18 h after endotoxin (4 mg kg(-1), i.p.) injection compared with those in the endotoxin/Se-adequate diet group, whereas non-protein sulfhydryl level in the liver after administration of endotoxin to Se-deficient rats was lower than that in Se-adequate rats treated with endotoxin. We investigated whether Se can suppress nitric oxide (NO) generation and cytotoxicity in endotoxin-treated J774A.1 cells. Treatment with Se (10(-6) M) markedly inhibited endotoxin (0.1 microg ml(-1))-induced NO production in J774A.1 cells. Se induced an increased activity of GSH-Px in cells after 24 h of incubation, suggesting that the preventive effect of Se on NO production in endotoxemia is due to the induction of Se-GSH-Px activity. However, Se did not affect endotoxin-induced cytotoxicity in J774A.1 cells. These findings suggested that the oxidative stress caused by endotoxin may be due, at least in part, to changes in Se regulation during endotoxemia.

Modification of tumor necrosis factor-induced acute toxicity D-galactosamine challenge by polymyxin B, an anti-endotoxin

Polymyxin B (PMB), an antibiotic with anti-endotoxin activity, was used to examine the participation of endogenously produced endotoxin in the enhancement of recombinant human tumor necrosis factor (rhTNF)-induced toxicity in D-galactosamine (GalN)-sensitized mice. GalN-sensitized mice (700 mg/kg, intraperitoneally (i.p.)) injected together with rhTNF (1x10(4) U/mouse, intravenously (i.v.)) exhibited severe symptoms, with 100% mortality at 18 h. However, mice pretreated with PMB (20 mg/kg, i.p.) showed protection against the rhTNF-induced lethality following GalN sensitization. Little or no effects were observed on alanine aminotransferase (ALT) activity or lactate dehydrogenase (LDH) isozyme leakage in serum in mice 7 h after administration of rhTNF alone. Administration of rhTNF to GalN-sensitized mice resulted in marked increases in ALT activity and LDH isozyme leakage relative to those in mice treated with rhTNF alone. In mice pretreated with PMB, the levels of ALT and LDH isozyme leakage 7 h after rhTNF/GalN injection were significant decreased as compared with those in mice treated with rhTNF/GalN. Similarly, injection of PMB markedly decreased lipid peroxide formation in the liver of the GalN-sensitized mice treated with rhTNF. The injection of a low endotoxin dose (0.1 mg/kg, i.p.) markedly increased the lethality in mice treated with rhTNF (5x10(3) U/mouse, i.v.) and GalN, and these animals showed 100% mortality at 8 h. These findings suggested that the extent of TNF-induced toxicity caused by GalN administration may be a result of synergism between TNF and gut-derived endotoxin. It is likely that endogenously produced endotoxin play a significant role in rhTNF/GalN-hypersensitized mice.

Enhancement of doxorubicin activity in multidrug-resistant cells by mefloquine

We studied the effect of the antimalarial drug mefloquine on the resistance of K562 cells to doxorubicin. Mefloquine synergistically potentiated the cytotoxicity of doxorubicin for doxorubicin-resistant K562 cells (K562/DXR) at a concentration of 0.5-3 microM, but had hardly any synergistic effect in the parental cell line (K562) at the same concentration. Mefloquine was more potent than verapamil, a known modulator of multidrug-resistance. Since doxorubicin resistance in these cells is associated with the expression of high levels of P-glycoprotein, we evaluated the effect of mefloquine and of P-glycoprotein activity in cytofluorographic efflux experiments with the fluorescent dye rhodamine 123. Our results indicate that mefloquine inhibits the P-glycoprotein pump-efflux activity in a dose-related manner. Moreover, mefloquine reduces the expression of the immunoreactive P-glycoprotein in K562/DXR cells as evaluated by cytofluorimetric assay. Taken together, the results indicate that mefloquine reverses the multidrug-resistance phenotype through direct interaction with P-glycoprotein.

Potentiation of acetaminophen hepatotoxicity by doxapram in mouse primary cultured hepatocytes

The augmentation by doxapram (DOP) of the reduction in viability and of the apoptosis of cells induced by acetaminophen (AA) was examined in mouse primary cultured hepatocytes. Loss of viability on exposure to AA and/or DOP in cultured hepatocytes was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and the apoptosis of cultured hepatocytes was detected by nuclear morphologic observation and from a ladder-like DNA fragmentation pattern. The combination of AA (5 mM) and DOP (10, 20, 50 or 100 microM) potentiated the reduction in cell viability and increased the oxidative stress. Hepatocytes exposed for 24 h to AA (5 mM) plus DOP (100 microM), showed atrophy of nuclei, including chromatin condensation and a ladder-like DNA fragmentation pattern, characteristic of apoptosis. Benzyl-oxycarbonyl-Asp-CH2OC (O)-2,6-dichlorobenzene (Z-Asp-CH2-DCB, 50 microM), an inhibitor for caspases, improved the viability and ladder-like DNA fragmentation in cells exposed to DOP (200 or 500 microM) alone or AA ( 5 mM) plus DOP (100 microM). However, loss of viability on exposure to a high concentration of AA (10 mM) and ladder-like DNA fragmentation were not affected by Z-Asp-CH2-DCB. These results indicated that the synergistic increase in oxidative stress, activation of caspases and DNA fragmentation induced by DOP potentiated the hepatotoxicity of AA.

Effect of nitric oxide synthase inhibitors on lipid peroxide formation in liver caused by endotoxin challenge

This study investigated the effect of nitric oxide on lipid peroxide formation during endotoxaemia. Nitric oxide synthase inhibitors N(G)-monomethyl-L-arginine acetate (L-NMMA, 20 mg/kg, intravenously), N(G)-nitro-L-arginine-methyl ester (L-NAME, 10 mg/kg, intravenously), and N(G)-nitro-L-arginine (L-NA, 10 mg/kg, intravenously), and a relatively selective inducible nitric oxide synthase inhibitor aminoguanidine (10 mg/kg, intravenously), did not protect against endotoxin-induced death of mice. Superoxide dismutase activity in liver 18 hr after administration of endotoxin (6 mg/kg, intraperitoneally) to L-arginine analogues (L-NMMA, L-NAME, L-NA)-treated mice was lower than in mice treated with endotoxin alone, whereas the administration of L-arginine analogues increased xanthine oxidase activity in the livers of endotoxin-injected mice compared with mice treated with endotoxin alone. In mice treated with L-arginine analogues and aminoguanidine, the levels of non-protein sulfhydryl and lipid peroxide in liver 18 hr after endotoxin injection did not show significant differences from mice treated with endotoxin alone. L-Arginine analogues and aminoguanidine had little effect on lipid peroxide formation in liver caused by endotoxin. Treatment with aminoguanidine (300 microM) significantly inhibited endotoxin-induced intracellular peroxide in J774A.1 cells, however, aminoguanidine did not affect endotoxin-induced cytotoxicity in J774A.1 cells. Our results clearly demonstrate that treatment with catalase (10 microg/ml), D-mannitol (10 mM), or superoxide dismutase (100 U/ml), has little or no effect on nitric oxide production by endotoxin (1 microg/ml)-activated J774A.1 cells. These findings suggest that nitric oxide is not crucial for lipid peroxide formation during endotoxaemia. Therefore, it is unlikely that nitric oxide plays a significant role in liver injury caused by free radical generation in endotoxaemia.

Reversal of multidrug resistance in human leukemia K562 by tamolarizine, a novel calcium antagonist

A new type of organic Ca2+ channel blocker, tamolarizine, was examined for its reversing effect on multidrug-resistant tumor cells. Tamolarizine synergistically potentiated the cytotoxicity of doxorubicin for doxorubicin-resistant K562 cells (K562/DXR) at a concentration of 0.1-10 microM, but had hardly any synergistic effects in the parental cell line (K562) at the same concentration. Moreover, tamolarizine inhibits the P-glycoprotein pump-efflux activity in a dose-related manner and reduces the expression of the immunoreactive P-glycoprotein in K562/DXR cells as evaluated by cytofluorimetric assay. These results indicate that tamolarizine reverses the multidrug-resistance phenotype through direct interaction with P-glycoprotein.

Reversal of acquired resistance to doxorubicin in K562 human leukemia cells by astemizole

This study demonstrates that astemizole, a non-sedating anti-histaminergic drug with low toxicity in vivo, greatly potentiates the growth-inhibitory activity of doxorubicin in doxorubicin-resistant human leukemia cells (K562/DXR). Astemizole synergistically potentiated the cytotoxicity of doxorubicin for K562/DXR cells at a concentration of 0.1-3 microM in a dose-dependent manner, whereas they showed hardly any synthergistic effect in the parental cell line (K562) at the same concentration. Since doxorubicin resistance in these cells is associated with the expression of high levels of P-glycoprotein, we evaluated the effect of astemizole on P-glycoprotein activity in cytofluorographic efflux experiments with doxorubicin. Our results indicate that astemizole inhibits the P-glycoprotein pump-efflux activity in a dose-related manner. Moreover, it also inhibits the photolabeling of P-glycoprotein by [3H]azidopine in a dose-dependent manner. These findings provide a biological basis for the potential therapeutic application of astemizole as an anticancer drug either alone or in combination with doxorubicin to multidrug-resistant leukemic cells.

Role of endogenous endotoxin on tumor necrosis factor-hypersensitivity caused by D-galactosamine challenge

We examined the role of endotoxin in the mechanism of recombinant human tumor necrosis factor (rhTNF)-hypersensitivity caused by D-galactosamine (GalN). We used polymyxin B, an antibiotic with anti-endotoxin activity, to determine the participation of endogenous endotoxin. The glycogen and blood glucose level of rhTNF (1 x 10(4) units/mouse, i.v.)-injected mice was lower at 7 h post-intoxication than that in the control. Administration of rhTNF to GalN (700 mg/kg, i.p.)-treated mice resulted in lower levels of glycogen and blood glucose than those in animals treated with rhTNF alone. In mice pretreated with polymxin B (20 mg/kg, i.p.), the level at 7 h after rhTNF/GalN-injection was markedly increased compared to that in mice treated with rhTNF/GalN alone. The injection of a low endotoxin dose (0.1 mg/kg, i.p.) markedly decreased the rectal temperature in mice treated with rhTNF (5 x 10(3) units/mouse, i.v.) and GalN, and none of these animals survived after treatment for 18 h. These findings suggest that endogenously produced endotoxin may contribute to the extent of rhTNF-hypersensitivity caused by GalN.

Characterization of hydrogen peroxide-induced apoptosis in mouse primary cultured hepatocytes

The influence of oxidative stress by hydrogen peroxide (H2O2) was examined in mouse primary cultured hepatocytes. A change in morphology was observed in hepatocytes incubated for 30 min in saline A containing H2O2. The percentage of dead cells, as measured by the fluorescence method, was increased in a dose-dependent manner. In addition, a ladder-like DNA fragmentation pattern was detected by agarose gel electrophoresis 1 h after exposure to 3 mM H2O2. This phenomenon was prolonged for 24 h. Hydrogen peroxide-induced cell viability reduction and DNA fragmentation were dose-dependently protected by the addition of antioxidants (N-acetylcysteine, L-ascorbic acid), a metal-chelator (1,10-phenanthroline), iron-chelator (deferoxamine) and intracellular calcium ion chelator (quin 2-AM). No influence, however, was detected by endonuclease inhibitors (zinc, aurintricarboxylic acid) and poly (ADP-ribose) polymerase inhibitors (3-aminobenzamide, theophylline). These results following H2O2-induced cell viability reduction suggested that oxidative stress by H2O2 itself or H2O2-derived changes involved in ferrous or intracellular calcium ions resulted in apoptosis in mouse primary cultured hepatocytes. These phenomena are not likely to be associated with endonuclease or poly (ADP-ribose) polymerase.

Combination acetaminophen and doxapram potentiated hepatotoxicity in mouse primary cultured hepatocytes

Doxapram-induced potentiation of acetaminophen-induced reductions in cell viability and apoptosis was examined in mouse primary cultured hepatocytes. Loss of viability following exposure of acetaminophen and/or doxapram in cultured hepatocytes was assessed by monitoring [3H]-thymidine incorporation and mitochondrial activity, and apoptosis of hepatocytes was determined by nuclear microscopic observation and from detection of a ladder-like DNA fragmentation pattern in agarose gel electrophoresis. The combination of acetaminophen (5 mM) and doxapram (10, 20, 50 or 100 microM) potentiated the reduction in cell viability and increased lipid peroxide levels of hepatocytes. Hepatocytes exposed for 24 h to acetaminophen (5 mM) plus doxapram (100 microM) showed atrophy of nuclei including chromatin condensation and a ladder-like DNA fragmentation pattern characteristic of apoptosis. Antioxidant (N-acetylcysteine), iron-chelator (deferoxamine), intracellular calcium ion chelator (quin 2-AM), endonuclease inhibitor (aurintricarboxylic acid) and poly (ADP-ribose) polymerase inhibitor (3-aminobenzamide) all improved the viability of cells and eliminated the ladder-like DNA fragmentation in cells exposed to acetaminophen plus doxapram. In conclusion, the combination acetaminophen and doxapram potentiated the reduction in cell viability and apoptosis in mouse primary cultured hepatocytes. We suggest that careful observation for hepatotoxicity is recommended when acetaminophen and doxapram are prescribed simultaneously.

Exposure to hydrogen peroxide induces cell death via apoptosis in primary cultured mouse hepatocytes

To investigate whether direct oxidant damage induces hepatotoxicity via an apoptotic cell suicide pathway, we exposed primary cultured mouse hepatocytes to pro-oxidant hydrogen peroxide. We demonstrate that brief exposure to a concentration of hydrogen peroxide (3 mM) can induce hepatocyte cell death via apoptosis as shown by toxicity assays, specific DNA staining, and the appearance of DNA laddering on agarose gels. When hepatocytes were treated with N-acetylcysteine 15 min prior to hydrogen peroxide exposure, the cells were found to be protected from cytotoxicity and apoptosis. These results suggest that direct oxidative injury serves as a general trigger for apoptosis in the liver, and that other apoptotic stimuli, such as exposure to acetaminophen, also involve oxidative injury. Hydrogen peroxidase-induced apoptosis may serve as a valuable model for further studies of apoptosis in the liver.

Tandem repeat structure of rhamnose-binding lectin from catfish (Silurus asotus) eggs

The primary structure of catfish (Silurus asotus) egg lectin (SAL) was determined. SAL cDNA contained 1448-bp nucleotides and 308 amino acid residues, deduced from open reading frame. The SAL mature protein composed of 285-amino acid residues was followed by a predicted signal sequence having 23 residues. The mRNA of SAL was found to be expressed in eggs, but not in liver. SAL is composed of three tandem repeat domain structures divided into exactly 95 amino acid residues each, and all cysteine positions of each domain were completely conserved. Sequence homologies between the three domains, termed D1 (1-95), D2 (96-190) and D3 (191-285), were as follows; D1-D2, 28%; D2-D3, 33%; D1-D3, 43%. Two conserved peptide motifs, -(AN)YGR(TD)S(T)XCS(TGR)P- and -DPCX(G)T(Y)KY(L)-, appear to exist at the N- and C-terminal regions of each domain, respectively. The kinetic parameters of SAL obtained by measuring surface plasmon resonance were as follows: K(a) (M(-1)) for neohesperidosyl-BSA, 7. 1 x 10(6); for melibiosyl-BSA, 4.9 x 10(6); and for lactosyl-BSA, 5. 2 x 10(5). These results show that RBLs including SAL comprise a family of alpha-galactosyl binding lectins having characteristic tandem repeat domain structures.

Hot water extract of bark of Nikko maple (Acer nikoense) induces apoptosis in leukemia cells

In screening for antitumor constituents in traditional crude drugs, we used three cultured cell lines: mouse leukemia P388 cells, doxorubicin-resistant P388 cells and leczyme (catalytic lectin)-resistant P388 cells. The hot water extract (HWE) of the bark of Nikko maple (Acer nikoense) showed concentration-dependent inhibitory effects on the growth of these three cell lines. DNA fragmentation and morphological changes, accompanied by condensed and fragmented nuclei, were observed in the leukemia cell lines cultured with HWE of the bark of Nikko maple. Treatment with this HWE increased the expression of sialylated glycoconjugates on the apoptotic cells. These results suggest that HWE induces cell death via apoptosis in vitro.

Potentiation of acetaminophen hepatotoxicity and mortality by doxapram in mice

Whether a single dose of doxapram (DOP) can modulate the acute toxicity and the hepatotoxicity induced by acetaminophen (AA) was examined. Pretreatment with DOP (40 mg/kg, i.p.) 30 min prior to the administration of AA dose-dependently potentiated the lethality of AA in both native mice and mice fasted for 18 h, and the potentiating activity was greater in fasted mice than in native mice. The hepatotoxicity of AA was assessed by plasma transaminases activity (glutamyl oxaloacetic transaminase, GOT; glutamyl pyruvic transaminase, GPT) and the amount of plasma lipid peroxides at 6, 12, 18, 24, 36 and 48h after the administration of AA and histopathological examination of liver sections at 24 h after the administration of AA. DOP (40 mg/kg, i.p.) did not increase the plasma transaminase activity or the lipid peroxides level significantly, whereas AA administration to DOP-treated animals produced earlier maximal elevation of transaminase and lipid peroxide values compared to AA alone. These findings indicate that mortality and hepatotoxicity of AA is potentiated by DOP in mice.

Thalidomide promotes the release of tumor necrosis factor-alpha (TNF-alpha) and lethality by lipopolysaccharide in mice

We investigated the in vivo effects of thalidomide on the production of tumor necrosis factor-alpha (TNF-alpha). An in vivo systemic release of TNF-alpha occurred after the injection of lipopolysaccharide (LPS) in male ddY mice, and the TNF-alpha serum levels reached 652.2 +/- 75.7 pg/ml 90 min after the injection of LPS (0.3 mg/kg, i. p.). When thalidomide (1, 3, or 6 mg/kg) was administered intraperitoneally 3 h before the injection of LPS (0.3 mg/kg, i. p.), thalidomide markedly enhanced LPS-induced TNF-alpha release in a dose-dependent manner. The TNF-alpha serum levels at 90 min were 640 +/- 58.6, 1985 +/- 132.6, and 2795 +/- 203.5 pg/ml, respectively, compared to 628.6 +/- 64.4 pg/ml in mice treated with LPS-alone. Pretreatment with a single injection of thalidomide (1, 3, or 6 mg/kg, i. p.) dose-dependently increased the subsequent mortality caused by a challenge with LPS (15 mg/kg, i. p.), a dose that caused death in 10% of the control mice. We conclude that thalidomide enhances in vivo TNF-alpha secretion and the lethality of LPS in mice.

Cepharanthine inhibits proliferation of cancer cells by inducing apoptosis

Cepharanthine, a biscoclaurine alkaloid extracted from Stephania cepharantha Hayata was examined for a possible apoptosis-inducing effect in murine P388 doxorubicin-sensitive (P388/S) and -resistant (P388/DOX) cells. A significant increase in LDH release from cells was observed after P388/S and P388/DOX cells had been exposed to cepharanthine for 24 h. Cepharanthine (10 micrograms/ml) markedly induced apoptosis in resistant cells after 6 h and 24 h. By the means of agarose electrophoresis the DNA ladder was detected in cell lines treated with cepharanthine for 24 h. Cepharanthine (1-10 micrograms/ml) also induced the production of reactive oxygen species in P388/DOX cells, while no such cepharanthine-induced increase in reactive oxygen species was observed in P388/S cells. Flow cytometry analysis showed a high level of Fas-antigen expression in P388/DOX cells treated with cepharanthine. Furthermore, we found that the inhibitition of DNA and protein synthesis caused by cepharanthine (10 micrograms/ml) was more significant in resistant cells than in sensitive cells. Cepharanthine had no effect on the GSH content of P388/S and P388/DOX cells. Our experimental results suggest that cepharanthin can induce apoptosis both in P388/S and P388/DOX cells, especially in the latter. Apoptosis induced by cepharanthine may be implicated in the production of reactive oxygen species and Fas-antigen expression in tumor cells.

Apoptotic cell death induced by physarumin (hemagglutinin from myxomycete, Physarum polycephalum)

Physarumin, a carbohydrate-binding protein (hemagglutinin or lectin), was isolated from the plasmodium of Physarum polycephalum. Physarumin agglutinated not only several species of erythrocytes but also tumor cells such as AH109A ascites hepatoma cells, sarcoma 180 ascites cells and mouse leukemia P388 cell lines. Physarumin had tumor cell growth-inhibitory activity, and induced the apoptosis of P388 cell lines. Physarumin-induced apoptosis required binding to a 68 kDa counter-receptor on the P388 cell surface. Since the agglutinating and antiproliferative activities of physarumin were inhibited by asialofetuin and thyroglobulin, respectively, it is suggested that physarumin reacts with the galactose moiety of carbohydrate chains of physarumin receptor.

Potentiation of pirarubicin activity in multidrug resistant cells by rifampicin

The effect of the anti-tuberculosis drug rifampicin on pirarubicin activity was investigated in multidrug-resistant cells overexpressing P-glycoprotein. Rifampicin increased the sensitivity of pirarubicin to anthracycline-resistant mouse leukemic P388 cells and significantly enhanced the cytotoxicity and intracellular accumulation of pirarubicin in resistant cells, but had no effect in parent cells. By contrast, two other rifamycins, rifamycin B and SV, had no effect on pirarubicin accumulation in resistant cells. Rifampicin also enhanced pirarubicin-induced apoptosis and G2/M blockade on the cell cycle in resistant cells. These results show that rifampicin enhances the cytotoxic action of pirarubicin in resistant cells, at least partly via the inhibition of cellular pirarubicin efflux.

Reversal of multidrug resistance by tacrolimus hydrate

Tacrolimus hydrate, a potent immunosuppressant produced by Streptomyces tsukubaensis, was examined for its effect on epirubicin activity in multidrug-resistant P388 leukemia (P388/R) cells overexpressing P-glycoprotein and the parent (P388/S) cells. In the absence of modulator, the 50% inhibitory concentration for epirubicin after 48-h incubation, determined using a microculture tetrazolium assay, was 0.8 microgram/ml in P388/R cells and 0.009 microgram/ml in P388/S cells. P388/R cells demonstrated a 90-fold reduction in sensitivity to epirubicin. Tacrolimus hydrate (1 and 10 microM) markedly enhanced epirubicin cytotoxicity by 4.2- and 26.7-fold for P388/R cells. A significant increase in LDH release from cells by tacrolimus hydrate was also observed in P388/R cells treated with epirubicin. Tacrolimus hydrate had a marked effect on epirubicin-induced G2/M blockade in the resistant cells. Both tacrolimus hydrate and cyclosporin A dramatically increased the accumulation of epirubicin by the resistant cells, while these compounds had no effect on epirubicin accumulation in the parent cells. Thus, tacrolimus hydrate is able to down-modulate P-glycoprotein-associated resistance through inhibition of P-glycoprotein function, suggesting that the drug may be a candidate for killing drug-resistant tumor cells.

The enhancing effect of tumour necrosis factor-alpha on oxidative stress in endotoxemia

The enhancing effect of tumour necrosis factor-alpha (TNF-alpha) on oxidative stress with or without a sublethal dose of endotoxin was examined. The mortality of mice treated with recombinant human TNF-alpha (1 x 10(4) units/mouse, intravenously) and endotoxin (0.01-1 mg/kg, intraperitoneally) was dependent on the dose of endotoxin. The liver lipid peroxide level, superoxide anion generation and serum lactate dehydrogenase activity, especially serum lactate dehydrogenase-5 isozyme leakage, in mice 2-4 hr after administration of recombinant human TNF to endotoxin-pretreated mice (0.5 mg/kg, intraperitoneally) were markedly higher than in those without endotoxin, whereas the administration of recombinant human TNF significantly decreased the non-protein sulfhydryl level, superoxide dismutase and glutathione peroxide activities in the liver of endotoxin-injected mice compared with those in mice treated with recombinant human TNF or endotoxin alone. Furthermore, findings clearly demonstrated that J774A.1 cells stimulated with recombinant human TNF (1 x 10(4) units/ml) can effectively produce nitric oxide in the presence of endotoxin, and the production was dependent on the dose of endotoxin (0.01-10 micrograms/ml). The level of lipid peroxide in mice 4 hr after administration of recombinant human TNF and lead acetate (50 mg/kg, intravenously) was markedly higher than that in the mice treated with recombinant human TNF alone. By contrast, injection of polymyxin-B (20 mg/kg, intraperitoneally, an anti-endotoxin drug) markedly decreased the lipid peroxide level in the liver of the mice treated with recombinant human TNF and lead acetate. These findings suggest that the oxidative stress caused by TNF occurs as a enhancing effect of endotoxin or by bacterial translocation from the intestinal gut under reduction of reticuloendothelial system function in various disease states, and that the effect of TNF may cause a marked increase of toxicity of oxidative stress by endotoxin.

Effects of antitumor activity and protection of shock symptoms by a traditional Chinese medicine (sho-saiko-to) in recombinant human tumor necrosis factor administered mice

The effects of a traditional Chinese medicine Sho-saiko-to (Kampo prescription) were investigated on the various metabolic disorders and antitumor activity of recombinant human tumor necrosis factor (rhTNF) administered to mice. The glycogen level in liver of rhTNF (5 x 10(4) units/mouse, i.v.)-injected mice was markedly lower at 4 h post-intoxication than that in the control, whereas the administration of rhTNF to Sho-saiko-to (500 mg/kg/d, p.o.)-pretreated mice resulted in a greater level of glycogen than that in rhTNF alone-treated mice. In mice pretreated with Sho-saiko-to, the level of fibrinogen 4 h after rhTNF injection markedly increased as compared to that in mice treated with rhTNF alone. We also estimated the NO2 in murine macrophage cell line J774A.1 using mice serum after administration of Sho-saiko-to. Our results clearly demonstrated that J774A.1 cells stimulated with endotoxin (1 micrograms/ml) and rhTNF (1 x 10(4) units/ml) can effectively produce nitric oxide (NO), and ascertained the suppressive effect of Sho-saiko-to (500 mg/kg/d, p.o)-pretreated serum on NO generation by endotoxin/TNF-activated J774A.1 cells. When the cells were incubated with endotoxin/TNF and Sho-saiko-to pretreated serum (10-100 microliters), the NO level was significantly lower than that in control serum incubated with endotoxin/TNF alone. The effect of Sho-saiko-to (1 and 10 micrograms/ml) on in vitro cytotoxicity by rhTNF in Meth-A Sarcoma cells was observed to be in a dose dependent fashion. In addition, there was a remarkable enhancement of antitumor activity of rhTNF by Sho-saiko-to pretreatment in mice. These findings suggest that the Kampo prescription Sho-saiko-to may protect mice from severe shock syndrome by rhTNF, and that it may enhance rhTNF-induced activity.

[Studies on reversing effect of multidrug resistance by dipyridamole. I. modulation of epirubicin-induced effects on cell proliferation and cell cycle by dipyridamole]

Dipyridamole, a nucleoside membrane transport inhibitor, enhanced the cytotoxicity of epirubicin for mouse leukemia P388 cells by a factor of 1.8-fold and that for 30-fold doxorubicin-resistant sublines of P388 cells (P388/DOX) by a factor of 6.5-fold. This interaction was shown to be truly synergistic by DNA histogram and median effect analysis. The dipyridamole enhancement of the cytotoxicity of epirubioin was a dose-dependent effect; it was greatest when cells were exposed to dipyridamole before treatment with epirubicin. In cell cycle experiments, 1-5 microM dipyridamole increased the accumulation of G2 + M phase produced by the treatment with 0.5-1 microM epirubicin. Dipyridamole, however, did not appear to alter the patterns of DNA histogram in sensitive cells. These results suggest that the increase of the accumulation of G2 + M phase in resistant cells is an important factor for the interaction between epirubicin and dipyridamole.

Augmentation of epirubicin cytotoxicity by cycloheximide

The effect of cycloheximide (CH) on the cytotoxic activity of the anthracycline antibiotic epirubicin (EPI) was examined in cell cultures of murine leukemia doxorubicin (DOX)-sensitive P388 and -resistant P388 cells. The addition of CH (0.002 mu g/ml) to the growth medium markedly enhanced the EPI-induced cytotoxic effect in sensitive cells as well as that observed in resistant cells. CH, however, did not affect the intracellular content of EPI. The inhibition of DNA synthesis in leukemia cells was remarkable with the combination of EPI and CH compared with each drug alone. These results suggest that the combination of EPI and CH appears to be useful in killing mouse leukemia cells.

Inhibition of doxorubicin-induced cell death in vitro and in vivo by cycloheximide

We studied the effects of the protein synthesis inhibitor, cycloheximide (CH), on cell killing by doxorubicin (DOX) in vitro and in vivo. At the concentration of CH used (1 microgram/ml) the cytotoxicity of DOX was reduced in cultured P388 leukemia cells. An analysis of the DNA histogram obtained by flow cytometry showed that DOX exerts its growth-inhibitory effect by blocking the cell cycle at the G2/M phase in P388 cells. Treatment with CH diminished this blocking effect. When CH was added to the growth medium before DOX exposure, no change in intracellular DOX accumulation was observed. Treatment with CH (15 mg/kg) significantly diminished the lethality of DOX (20 mg/kg) in mice and it also reduced the antitumor activity of mice with P388 leukemia. Thus, CH inhibited cell death induced by DOX in vitro and in vivo. These results suggest that CH has an antagonistic effect on the pharmacological actions of DOX in cells and mice. The cytoprotective effect of CH may be due to protein synthesis inhibition.

Effect of glutathione depletion by buthionine sulfoximine on doxorubicin toxicity in mice

The role of the glutathione (GSH) system in vivo or in drug resistance has received much attention, since GSH is a major component of the cellular detoxification system. We Studied the effect of GSH depletion by buthionine sulfoximine (BSO), a potent inhibitor of gamma-glutamylcysteine synthetase, on doxorubicin (DOX) toxicity in mice. The administration of BSO (30 mM in drinking water for 5 days) significantly decreased the tissue GSH. The GSH depletion in various tissues by BSO was associated with a decrease in the detoxification of DOX in mice. A single dose of 20 mg/kg of DOX significantly reduced body weight and rectal temperature in mice 3 days after injection. The combination with BSO and cepharanthine (biscoclaurine alkaloid), a P-glycoprotein (P-gp) inhibitor, significantly potentiated decrease in body and hypothermia induced by DOX. The study demonstrates that BSO markedly increases the toxicological effect of DOX with the alterations in GSH of tissues and Suggests that the intracellular accumulation of DOX is not a factor.

Depressive effect of a traditional Chinese medicine (sho-saiko-to) on endotoxin-induced nitric oxide formation in activated murine macrophage J774A.1 cells

The present study investigated whether or not Sho-saiko-to (crude powder extract, TJ-9) can suppress nitric oxide (NO) generation by endotoxin-activated J774A.1 cells in order to study the preventive mechanism of Sho-saiko-to against endotoxemia. In this experiment, we estimated the NO2- in the murine macrophage cell line J774A.1 using the Griess method. Our results clearly demonstrated that J774A.1 cells stimulated with endotoxin (0.01-10 micrograms/ml) can effectively produce NO, and the production was dependent on the dose of endotoxin. On the other hand, we investigated the suppressive effect of TJ-9 (10-100 micrograms/ml) on NO generation by endotoxin (0.1 microgram/ml)-activated J774A.1 cells. The NO level when the cells were incubated with endotoxin and TJ-9 (10-20 micrograms/ml) was slightly lower than that in cells treated with endotoxin alone. In contrast, treatment with TJ-9 (50-100 micrograms/ml) significantly inhibited endotoxin-activated NO generation in J774A.1 cells, whereas the treatment with TJ-9 (10-100 micrograms/ml) alone was ineffective in inducing NO formation and in inhibiting cell viability in the J774A.1 cells. These findings suggest that a Kampo presciption of Sho-saiko-to shows a suppressive effect on NO generation in macrophages stimulated with endotoxin, and that it may be useful in improving endotoxin-shock symptoms.

Protection against cisplatin lethality and renal toxicity by chlorpromazine in mice

The effect of chlorpromazine on acute lethal toxicity and nephrotoxicity induced by cisplatin was studied in mice. Chlorpromazine (i.p.) given 1 h before cisplatin greatly reduced lethal and renal toxicities of cisplatin, while chlorpromazine did not reduce the antitumor activity of cisplatin against sarcoma 180 in ddY mice or El-4 leukemia in C57BL/6J mice.

Structure of the 5' upstream region and the regulation of the rpoS gene of Escherichia coli

The nucleotide sequence of the 5' upstream region of the Escherichia coli rpoS gene was determined and analyzed. At least four promoters responsible for rpoS transcription were identified, and designated P1, P2, P3 and P4, P1 being furthest from the upstream. Using lacZ fusion genes, the P2 promoter was found to be the strongest of the four. All of these promoters are regulated similarly, and their activity is enhanced 2 to 3-fold in stationary phase. P1 and P2 transcription start sites were determined by primer extension analyses. The P2 promoter region shows similarity to the consensus sigma 70-type promoter sequence, and was recognized by both E sigma 70 and E sigma 38 holoenzymes in vitro. The mRNA transcribed from the most distal promoter, P1, appears to include another open reading frame (orf-281), indicating that the two open reading frames comprise an operon. The rpoS gene product (sigma 38) was rapidly degraded after addition of chloramphenicol to cultures in the exponential, but not the stationary phase. This strongly suggests that posttranslational regulation is involved in the control of rpoS expression.

Drug interaction effects on antitumour drugs (XV): Disulfiram as protective agent against cyclophosphamide-induced urotoxicity without compromising antitumour activity in mice

The prevention of cyclophosphamide-induced urotoxicity by disulfiram was studied in mice. A single dose of cyclophosphamide (100-400 mg/kg, intraperitoneally) produced a significant dose-dependent increase in urinary bladder weight within 48 hr of treatment. Disulfiram prevented cyclophosphamide-induced bladder damage in a dose-dependent manner in mice when orally administered simultaneously with antitumour agents, but failed to diminish the acute toxicity, leukocytotoxicity and immunotoxicity of cyclophosphamide. The protective effect of disulfiram on the bladder was critically dependent on administration timing. Oral administration of disulfiram between 60 min. before and 60 min. after the injection of cyclophosphamide was found to be effective. The optimum time was simultaneous administration of both drugs. Diethyldithiocarbamate and carbon disulfide, metabolites of disulfiram, prevented cyclophosphamide-induced bladder damage when administered simultaneously with cyclophosphamide 1 to, 3 or 5 hr afterwards. Disulfiram slightly potentiated the antitumour activity of cyclophosphamide against Sarcoma 180 or EL-4 leukaemia in vivo when administered simultaneously with cyclophosphamide. In contrast, diethyldithiocarbamate or carbon disulfide did not interfere with cyclophosphamide antitumour activity when administered 3 hr after cyclophosphamide. From these preliminary studies, disulfiram appears to be a likely candidate for protection against cyclophosphamide-induced urotoxicity without compromising the therapeutic utility of the alkylating agent.

Inhibition of cell proliferation by Rana catesbeiana and Rana japonica lectins belonging to the ribonuclease superfamily

Two frog egg lectins [Rana catesbeiana lectin (SBL-C) and Rana japonica lectin] preferentially agglutinate a large variety of human and animal tumor cells but not blood cells, lymphocytes, or fibroblasts. These lectins belong to the superfamily of pyrimidine base-specific RNases. The two lectins bound to a heparin-Sepharose column and were eluted from the column by an increase of NaCl molarity. Both their tumor cell-agglutinating activity and RNase activity were inhibited by heparin, and also by polyamines, such as spermine. Both lectins inhibited P388 leukemia cell proliferation. The inhibitory activity of SBL-C was blocked by addition of heparin. SBL-C inhibited protein synthesis by P388 cells, but RNase A did not. No lectin-induced antiproliferative effect was observed after sialidase treatment of cells. The antiproliferative activity of SBL-C was also inhibited by ammonium chloride treatment. These results suggest that internalization of the lectins by lectin receptor (sialoglycoconjugate)-mediated endocytosis is followed by cell death due to inhibition of protein synthesis. Administration of SBL-C i.p. delayed time to death in mice receiving i.p. transplants of Sarcoma 180 and Mep II cells.