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BackgroundMalarial parasites are susceptible to oxidative stress. The effects of α-tocopheryloxy acetic acid (α-TEA), a vitamin E analog, on infection by Plasmodium berghei ANKA and P. falciparum in mice and human red blood cells (RBCs), respectively, were examined in this study. MethodsFor in vivo studies in mice, RBCs infected with P. berghei ANKA were inoculated via intraperitoneal injection and α-TEA was administered to C57BL/6J male mice after infection. The blood–brain barrier (BBB) permeability was examined by Evans blue staining in experimental cerebral malaria at 7 days after infection. The in vitro inhibitory effect of α-TEA on P. falciparum 3D7 (chloroquine-sensitive strain) and K1 (multidrug-resistant strain) was tested using a SYBR Green I-based assay.ResultsWhen 1.5 % α-TEA was administered for 14 days after infection, 88 % of P. berghei ANKA-infected mice survived during the experimental period. Nevertheless, all the control mice died within 12 days of infection. Furthermore, the Evans blue intensity in α-TEA-treated mice brains was less than that in untreated mice, indicating that α-TEA might inhibit the destruction of the BBB and progression of cerebral malaria. The in vitro experiment revealed that α-TEA inhibited the proliferation of both the 3D7 and K1 strains.ConclusionsThis study showed that α-TEA is effective against murine and human malaria in vivo and in vitro, respectively. Although α-TEA alone has a sufficient antimalarial effect, future research could focus on the combined effect of α-TEA and already existing drugs. The prophylactic antimalarial activity of premedication with α-TEA may also be an interesting perspective in the future.

Background Malaria parasites are known to be vulnerable to oxidative stress. In this study, the effects of the administration of α-tocopheryloxy acetic acid (α-TEA), which is a vitamin E analogue mitocan, on Plasmodium yoelii infection in mice were examined. Methods Alpha-TEA was mixed with diet and fed to C57BL/6J mice before and/or after infection. For parasite infection, 4 × 104 red blood cells infected with P. yoelii (strain 17XL) were inoculated by intraperitoneal injection. In another series of experiment, the effect of the oral administration of α-TEA on P. yoelii 17XL infection in mice was examined. Finally, the combined effect of α-TEA and dihydroartemisinin or chloroquine on P. yoelii 17XL infection was examined. Results When 0.25% α-TEA was mixed with the diet for 7 days before infection and 14 days after infection (in total for 21 days), for 14 days after infection, and for 11 days from the third day after infection, all P. yoelii 17XL-infected mice survived during the observation period. However, all control mice died within 12 days after infection. These results indicated that α-TEA functions effectively even when administered post-infection. The oral administration of α-TEA for P. yoelii 17XL infection was also significant. Although the infected mice in the solvent control died within 10 days after infection, 90% of the mice infected with P. yoelii 17XL survived during the observation period when treated with 10 mg/head/day of α-TEA for 3 days from day 3 after infection. Although the combined effect of α-TEA and dihydroartemisinin (DHA) or chloroquine on P. yoelii 17XL infection was significant, no synergistic or additive effects were observed from the survival curve. Conclusions This study showed the beneficial effects of α-TEA on the experimental infection of mice with P. yoelii 17XL. The stimulatory action of α-TEA on mitochondria and the accompanying reactions, such as reactive oxygen species production, and induction of apoptosis might have some effect on malarial infection.

α-Tocopheryl succinate (α-TOS), a derivative of vitamin E, is synthesized by esterification of α-tocopherol. It has been reported that α-TOS inhibits the mitochondrial complex II resulting in generation of reactive oxygen species, which triggers selective apoptosis in a large number of cancer cells, while it appears largely non-toxic towards normal cells. Plasmodium parasites are well known to have high sensitivity to oxidative stress. Thus, α-TOS is suspected to impact Plasmodium parasites by oxidative stress. In this study, to ascertain whether α-TOS is an appropriate candidate for an anti-malarial drug, C57BL/6J mice were infected with P. yoelii 17XL and P. berghei ANKA, a lethal strain of rodent malaria and experimental cerebral malaria (ECM), and treated with several concentrations of α-TOS by intraperitoneal administration on 1, 3, 5, and 7 days post infection (dpi). In addition, the permeability of the blood brain barrier (BBB) was examined by Evans blue staining in ECM on 7 dpi. As a result of α-TOS treatment, parasitemia was decreased and survival rate was significantly increased in mice infected with both parasites. Furthermore, the intensity of Evans blue staining on brains taken from α-TOS-treated mice was weaker than that of untreated mice. This means that α-TOS might inhibit the breakdown of BBB and progress of cerebral malaria. These findings indicate that vitamin E derivatives like α-TOS might be a potential candidate for treatment drugs against malaria.

We investigated the antidiabetic effects of E3030, which is a potent dual activator of peroxisome proliferator-activated receptor (PPAR) α and PPARγ, in an animal model of diabetes, C57BL/KsJ-db/db mice (db/db mice), and the lipidemic effects of E3030 in beagle dogs, whose PPARα and PPARγ transactivation responses to E3030 were similar to those of humans. E3030 activated human PPARα, mouse PPARα, dog PPARα, human PPARγ, mouse PPARγ, and dog PPARγ with EC50 values of 65, 920, 87, 34, 73, and 34 nM, respectively, in the chimeric GAL4-PPAR receptor transactivation reporter assay. In db/db mice orally administered E3030 decreased blood glucose, triglyceride (TG), non-esterified fatty acids (NEFA), and insulin levels and increased blood adiponectin levels during a 14-day experimental period. Significant effects on blood glucose and adiponectin levels were observed at a dose of 3 mg/kg or greater. Furthermore, significant effects on blood TG, NEFA, and insulin levels were observed at doses of 1 mg/kg or more. An oral glucose tolerance test (OGTT) performed on Day 15 showed that E3030 at 3 mg/kg improved glucose tolerance in this model. Fourteen days of oral treatment with E3030 at a dose of 0.03 mg/kg or greater showed remarkable TG- and non high-density lipoprotein (non-HDL) cholesterol–lowering effects in beagle dogs. These results were similar to those observed for the PPARα agonist fenofibrate. E3030 also reduced apo C-III levels on Days 7 and 14, and elevated lipoprotein lipase (LPL) levels on Day 15. These results indicate that the TG- and non-HDL cholesterol-lowering actions of E3030 involve combined effects on reduction of apo C-III and elevation of LPL, resulting in increased lipolysis. The experimental results in animals suggest that E3030 has potential for use in the treatment of various aspects of metabolic dysfunction in type 2 diabetes, including dyslipidemia, hyperglycemia, hyperinsulinemia, and impaired glucose disposal. Keywords:: E3030, peroxisome proliferator-activated receptor (PPAR) α, PPARγ, PPARα/γ agonist

Oxidative stress affects bone turnover. Preventative effects of antioxidants such as vitamin E on reduced bone mineral density and fractures associated with aging, osteoporosis, and smoking have been examined in animals and humans. The effects of vitamin E (α-tocopherol; αT) on bone health have yielded conflicting and inconclusive results from animal studies. In this study, to determine the bone effects of αT, we investigated the in vivo effects of αT on the bone mineral density, bone mass, bone microstructure, bone resorption, and osteogenesis through peripheral quantitative computed tomography (pQCT) measurements, micro-computed tomography (micro-CT) analyses, and bone histomorphometry of lumbar vertebrae and femurs in normal female Wistar rats fed diets containing αT in different quantities (0, 30, 120, or 600 mg/kg diet) for 8 weeks. To validate our hypotheses regarding bone changes, we examined ovariectomized rats as an osteoporosis model and control sham-operated rats in parallel. As expected, ovariectomized rats had reduced bone mineral density in lumbar vertebrae and the distal metaphyses of their femurs, reduced bone mass and deteriorated microstructure of cancellous bones in the vertebral body and distal femur metaphyses, and reduced bone mass due to resorption-dominant enhanced bone turnover in secondary cancellous bones in these sites. In comparison, αT administered to normal rats, even at the highest dose, did not induce reduced bone mineral density of lumbar vertebrae and femurs or a reduced bone mass or fragile microstructure of cancellous bones of the vertebral body and distal femur metaphyses. Instead, αT-fed rats showed a tendency for an osteogenesis-dominant bone mass increase in secondary cancellous bones in the vertebral body, in which active bone remodeling occurs. Thus, αT consumption may have beneficial effects on bone health.

The antitumor activity of mouse polymorphonuclear leukocyte (PMN) treated with a beta-1,3-D-glucan from Alcaligenes faecalis var. myxogenes IFO 13140 (TAK-N) and its carboxymethylated derivative (CM-TAK) was investigated in vitro and in vivo. ICR mouse PMN showed strong cytotoxicity against sarcoma 180 cells and inhibition of the growth of the tumor cells in vitro in the presence of TAK-N but not in the presence of CM-TAK. Since the cytotoxicity induced by TAK-N was almost completely inhibited by catalase, it seems to be mediated by H2O2 production by PMN. On the other hand, TAK-N induced no cytotoxicity in macrophages and neither did CM-TAK in PMN or in macrophage. Intraperitoneal injection of TAK-N into ICR mice induced a large number of PMN and macrophages in the peritoneal cavity. The peritoneal exudate PMN which were harvested at 10 to 72 h after TAK-N injection showed cytotoxicity against sarcoma 180 cells, but the peritoneal exudate macrophages did not. Treatment of sarcoma 180 ascites tumor-bearing ICR mice with TAK-N at a dose of 100 mg/kg prolonged significantly the survival time over that of the control. These results indicate that TAK-N induces PMN cytotoxicity against sarcoma 180 cells not only in vitro but also in vivo. The antitumor effect of TAK-N on sarcoma 180 ascites tumor seems to be derived from PMN stimulated with TAK-N.

A cell-separation technique was designed on the basis of specific interaction between macrophages and chemically modified collagens in the presence of serum. When unseparated mouse peritoneal exudate cells containing approximately 50% macrophages and 50% lymphocytes were incubated in dishes coated with unmodified and chemically modified collagens, only macrophages adhered more rapidly and in greater numbers to succinylated and methylated collagen than to unmodified collagen. The adherent macrophages could be easily detached from the substrata by divalent cation chelating agents. The purity and recovery of macrophages separated by this method were approximately 92-94% and 41-48%, respectively.

The relative fibrin-binding, fibrinolytic and fibrinogenolytic properties of single-chain pro-urokinase, an inactive proenzyme form of human urokinase purified from cultured human kidney cells, and urokinase were compared. The affinity of single-chain pro-urokinase for fibrin was much higher than that of urokinase. In Vitro thrombolytic studies showed that single-chain pro-urokinase is approximately three times more potent in fibrinolysis than urokinase and that it does not degrade fibrinogen in the plasma at a concentration, at which complete plasma clot lysis takes place; whereas, urokinase extensively degrades the fibrinogen in the plasma. These specific, potent thrombolytic properties of single-chain pro-urokinase seem to be due to its high affinity for fibrin and to its conversion from the inactive single-chain form to the active two-chain form on the thrombus by the catalytic amount of plasmin generated during coagulation. This single-chain pro-urokinase obtained from human kidney cells by tissue culture should prove advantageous than urokinase in thrombolytic therapy.

In order to study the relationship between the structure of pro-urokinase (pro-UK) and its clearance rate from circulation, three epidermal growth factor (EGF)-like domain deleted pro-UK mutants were constructed. Δ10–42, pro-UK, Δ10–45 pro-UK, and Δ10–49 pro-UK lacking Asn-10—Cys-42, Asn-10—Asp-45, and Asn-10—Thr-49, respectively, were compared with natural and recombinant pro-UKs (n-pro-UK and r-pro-UK) in terms of amidolytic activity and plasma clearance rate. Each pro-UK mutant gave almost the same enzymatic constants as n- and r-pro-UKs in terms of amidolytic activity. When 125I-labelled pro-UK and its derivatives were intravenously injected into rats, the clearance rate of pro-UK derivatives lacking EGF-like domain was significantly prolonged compared with those carrying intact EGF-like domain; for instance, the half-lives of Δ10–42 pro-UK, Δ10–45 pro-UK and Δ10–49 pro-UK were 8.2 ± 1.5 min, 6.3 ± 0.3 min and 7.1 ± 0.3 min, respectively, while those of n- and r-pro-UKs were 1.6 ± 0.1 min and 2.3 ± 0.0 min. Therefore, it is suggested that the pro-UK molecule is partially recognised and cleared by hepatic cells through EGF-like domain.

The bridging of IgG antibody molecules by either multivalent antigen or protein A adsorbed to a polymer surface triggers superoxide anion (O-2) generation from mouse peritoneal macrophages. Macrophages, upon stimulation with IgG adsorbed to a hydrophobic polymer, polystyrene, also significantly generated O-2. In contrast, soluble IgG did not stimulate macrophages. From these results we speculated that IgG adsorbed to polystyrene produces the same kind of a conformational change in its Fc region as seen in immune complexes, and leads to enhancement of the ability of the Fc region to bind macrophage Fc receptors, acting as a multivalent cross-linking agent to aggregate the Fc receptors. The surface charge density of the immunosorbent did not affect the antigen recognition function of antibody, but markedly affected its effector function. These findings suggest that activation of the Fc receptor-mediated function of macrophages requires, on the one hand, optimal conformational change and orientation of IgG and immune complexes adsorbed to the polymer surface and, on the other hand, the bridging of IgG molecules by multivalent agents.