خيارات البحث
النتائج 1 - 10 من 13
In vitro propagation of rabies virus in mouse dorsal root ganglia cells
2009
Hara, Y.(Hokkaido Univ., Sapporo (Japan)) | Sunden, Y. | Ochiai, K. | Umemura, T.
Rabies virus (RV) is highly neurotropic and migrates to the neuronal soma by retrograde axonal transport from nerve terminals, after which it is taken by anterograde axonal transport to be finally released into the central nervous system (CNS) from which it disseminates, resulting in lethal encephalitis. Dorsal root ganglia (DRG) are crucial in the initial events of the infection by RV since they can act as a gate for the viral entrance into the CNS. In the present study, we examined cell tropism of RV and the roles of neuronal cytoskeletal components in the production of viral nucleoprotein (N protein) using cultured nerve cells and non-neuronal cells from DRG of newborn mice. Our in vitro study demonstrated a low propagation rate of RV in nerve cells, susceptibility of non-neuronal cells to RV, and independence of cytoplasmic synthesis of viral N protein from the neuronal cytoskeleton. The present study also suggests that Schwann cells should be considered as another possible candidate supporting RV propagation.
اظهر المزيد [+] اقل [-]Evaluation of the potency, optimal antigen level and lasting immunity of inactivated avian influenza vaccine prepared from H5N1 virus
2009
Sasaki, T.(Kyoto Biken Lab. Inc., Uji (Japan)) | Isoda, N. | Soda, K. | Sakamoto, R. | Saijo, K. | Hagiwara, J. | Kokumai, N. | Ohgitani, T. | Imamura, T. | Sawata, A. | Lin, Z. | Sakoda, Y. | Kida, H.
Test vaccines comprised of inactivated water-in-oil emulsions containing various antigen levels were prepared using a non-pathogenic H5N1 avian influenza (AI) virus, A/duck/Hokkaido/Vac-1/04 (H5N1). The potencies of these test vaccines were evaluated by two experiments. In the first experiment, the triangular relationship among the antigen levels of test vaccines, the hemagglutination inhibition (HI) antibody response, and the protective effect against challenge with a highly pathogenic avian influenza (HPAI) virus, A/chicken/Yamaguchi/7/04 (H5N1), was confirmed. Then lasting immunity of chickens after a single-shot vaccination was confirmed in the second experiment. As a result, complete protection after the challenge was observed in chickens immunized by test vaccines with an antigen level of 160 HA units/dose or higher. Thus, it was ascertained that the minimum antigen level in the AI vaccine was 160 HA units/dose, and the minimum HI antibody titer that could protect chickens from HPAI virus infection-related death was considered to be 1:16. Dose-dependent HI antibody responses were observed in chickens after the vaccination. Thus, 640 HA units/dose were thought to be similar to the optimal antigen level. Alternatively, the HI antibody titers of chickens, injected with the vaccine containing 640 HA units/dose, were maintained at 1:181 or higher for 100 weeks after the single-shot vaccination.
اظهر المزيد [+] اقل [-]Protective effect of Pleurotus cornucopiae mushroom extract on carbon tetrachloride-induced hepatotoxicity
2009
Bohi, K.M.E.(Zagazig Univ., Kaluobyia (Egypt)) | Hashimoto, Y. | Muzandu, K. | Ikenaka, Y. | Ibrahim , Z.S. | Kazusaka, A. | Fujita, S. | Ishizuka, M.
Pleurotus cornucopiae (PC) mushrooms are found in the field and commonly known in Japan as Tamogidake mushrooms. The present study investigated the protective effects of an aqueous extract of PC on carbon tetrachloride (CCl4)-induced hepatotoxicity and the possible mechanism involved in this protection including cytochrome P450 (CYP) 2E1. Wistar rats were pretreated with aqueous extracts of PC (0, 100, 200, and 400 mg/kg) orally for 8 days prior to the intraperitoneal administration of a single dose of CCl4 (0.5 ml/kg) or corn oil. Pretreatment with PC mushroom extract significantly prevented the increased serum enzyme activities of alanine and aspartate aminotransferases in a dose-dependent manner, and suppressed the expression of CYP2E1. PC mushroom extract also protected hepatocytes from the damage effects of CCl4 as remarked by histological and electromicroscopical findings. It was concluded that repeated daily doses of aqueous extracts of PC mushroom reduced the toxic effects exerted by CCl4 on the liver.
اظهر المزيد [+] اقل [-]Proinsulin C-peptide induces c-Jun N-terminal kinase 1 expression in LEII mouse lung capillary endothelial cells
2009
Furuya, D.T., Hokkaido Univ., Sapporo (Japan) | Ishii, T. | Kamikawa, A. | Shimada, K. | Machado, U.F. | Saito, M.;Kimura | Kimura, K.
To characterize the roles of C-peptide in vascular homeostatic processes, we examined the genes regulated by C-peptide in LEII mouse lung microvascular endothelial cells. Treatment of the cells with C-peptide increased the expression of c-Jun N-terminal kinase 1 (JNK1) mRNA dose-dependently, accompanied by an increase in JNK1 protein content. Prior treatment of the cells with PD98059, an ERK kinase inhibitor or SB203580, a p38MAPK inhibitor, abrogated the C-peptide-elicited JNK1 mRNA expression. These results indicate that C-peptide increases JNK1 protein levels, possibly through ERK- and p38MAPK-dependent activation of JNK gene transcription.
اظهر المزيد [+] اقل [-]Radioecological investigation of food of animal origin in Belgrade environment
2009
Gordana, V., Belgrade Univ. (Serbia) | Svetlana, G. | Branislava, M. | Milan, O. | Branko, P.
The activity concentrations of sup(40)K, sup(238)U, sup(232)Th and sup(137)Cs were measured using gamma spectrometric method in different food chain samples from Serb Belgrade environment during the periods May-June 2007 and May-June 2008 year. Relatively high activities of sup(40)K and sup(137)Cs were detected in the soil. These results indicate that sup(137)Cs is present in Belgrade environment even 20 years after nuclear accident in Chernobyl. However, in the samples of feedstuffs, animal products and bio indicators (meat of wild animals and fish), activity concentrations of primordial radionuclides and sup(137)Cs were low and below the detection limits. Results of these trials have shown that investigated animal products from the natural environment around Belgrade, are radioactivity safe.
اظهر المزيد [+] اقل [-]A perspective on Theileria equi infections in donkeys
2009
Kumar, S.(National Research Centre on Equines, Haryana (India)) | Kumar, R. | Sugimoto, C.
The donkey population has remained unchanged in the last two decades despite a decrease in the overall population of equids, emphasizing the usefulness of the donkey as a draught and pack animal. Piroplasmosis in donkeys, caused by Theileria equi and Babesia caballi, has been recognized as a serious problem of major economic importance as the affected animals manifest decreased working capacity, loss of appetite, etc. In tropical countries, T. equi infections are more wide-spread and pathogenic than those caused by B. caballi. Donkeys usually remain asymptomatic carriers with positive antibody titres throughout life. Transmission of infection occurs from animal to animal through ticks such as Hyalomma spp. Rhipicephalus spp. and Dermacentor spp. The clinical form of the disease is diagnosed by peripheral blood smear examination, but in carrier donkeys it is very difficult to demonstrate the parasite in stained blood smears as the parasitaemia is extremely low. For diagnosis of such low grade infection or carrier animals, serological tests and DNA-based molecular diagnostic techniques, which are discussed in the present review, have become mandatory. Currently, there is no suitable pharmacotherapy available to clear the T. equi infection from affected donkeys, though some new drugs and drug combinations used against this disease condition have been discussed. In the present situation, there is an urgent need for international cooperation and coordination for development of sensitive molecular diagnostic tools and effective pharmacotherapies for curtailment of the disease condition. Hence, it is imperative to develop and exchange reagents and technology developed through human resource sharing in the interest of sustainability of donkey husbandry.
اظهر المزيد [+] اقل [-]Growth variation in skull morphology of Kuril harbor seals (Phoca vitulina stejnegeri) and spotted seals (Phoca largha) in Hokkaido, Japan
2009
Nakagawa, E., Hokkaido Univ., Sapporo (Japan) | Kobayashi, M. | Suzuki, M. | Tsubota, T.
We examined morphological growth variations in skull features between the Kuril harbor seal and the spotted seal in Hokkaido, Japan. Skulls from 80 Kuril harbor seals and 41 spotted seals were collected, and we measured 29 metric and 6 non-metric cranial characteristics. Three growth classes were defined according to the postnatal developmental stage: pups (0 year), subadults (1-4 years old) and adults (more than 5 years old). We detected sexual dimorphism in Kuril harbor seal pups, subadults, and adults. Although interspecies differences were detected in each growth class, Kuril harbor seals were larger and more massive than spotted seals; this feature was already detectable in pups. We did not detect certain cranial characteristics with which to identify the two species, but it was possible to identify any unknown specimens to their species, sex, and growth class using the cranial data generated in this study. Using 6 non-metric cranial characteristics, we identified significant interspecies differences with regard to the shape of the temporozygomatic suture and the extent of the nasal-incisive suture; the shape of the temporozygomatic suture and the shape of the nares were indicators of growth class in Kuril harbor seals. Although non-metric cranial characteristics have a lower discriminating power than metric characteristics, they are easy to use in the field even by inexperienced researchers.
اظهر المزيد [+] اقل [-]Strain differences of cerebral ventricles in mice: Can the MRL/MpJ mouse be a model for hydrocephalus?
2009
Hino, K.(Hokkaido Univ., Sapporo (Japan)) | Otsuka, S. | Ichii, O. | Hashimoto, Y. | Kon, Y.
Hydrocephalus is an intractable disease characterized by the excessive accumulation of cerebrospinal fluid (CSF) in the cerebral ventricles. There are many cases in both human and animals; however, the cause and mechanism of its development is not clearly understood. In this study, differences of cerebral ventricles in 5 inbred mice strains (MRL/MpJ, C57BL/6, C3H/He, DBA/2 and BALB/c) were investigated by histological techniques to determine the possibility of a new animal model for hydrocephalus. Our analysis showed that significant differences in the volume and the surface area of lateral ventricles in the 5 inbred strains, with MRL/MpJ mice having the largest lateral, third, aqueduct and fourth ventricles. In addition, when MRL/MpJ mice were compared to BALB/c mice on 0 day after birth, the former already had larger lateral ventricles than the latter. Although there was no significant difference in the ratios of ependymal cell types in MRL/MpJ mice and BALB/c mice, the number and the diameter of lipid droplets in MRL/MpJ mice were, interestingly, smaller than those in BALB/c mice. It is well known that ependymal cells absorb nutritional substances in CSF by endocytosis, suggesting the possibility that their decrease may relate to the larger cerebral ventricles in MRL/MpJ. In conclusion, MRL/ MpJ mice have greater volumes in cerebral ventricles than other strains and may be useful for a model showing high susceptibility to hydrocephalus.
اظهر المزيد [+] اقل [-]Change in body weight of mothers and neonates and in milk composition during denning period in captive Japanese black bears (Ursus thibetanus japonicus)
2009
Iibuchi, R.(Hokkaido Univ., Sapporo (Japan)) | Nakano, N. | Nakamura, T. | Urashima, T. | Shimozuru, M. | Murase, T. | Tsubota, T.
Japanese black bears, Ursus thibetanus japonicus, have been classified as a vulnerable species so that data on reproduction are needed to maintain and/or extend their population. They are known to have a peculiar style of reproduction, giving birth to their neonates and raising them during denning, a period of complete fasting. In this study, we investigated the metabolic rate and milk composition of mother bears raising neonates, and the changes in body weight of the neonates under captive conditions. Seven female bears kept in dens were weighed once a month, and the amount of energy they used was calculated. From birth, cubs were also weighed and their growth rate was determined. In addition, the milk composition was analyzed to investigate its characteristics. As a result, it was found that mother bears used 34% more energy than did solitary females. There was no significant difference in the energy used for nursing whether they had single or twin cubs. On the other hand, the body weight gain of single cubs was significantly higher than that of twin cubs, suggesting that the growth of the cubs was highly affected by the suppression of mother's energy consumption during the fasting period. The milk had high fat and low sugar concentrations. This indicates that mother bears used the fat accumulated prior to denning for their main energy source when raising cubs. Considering all results together, Japanese black bears showed remarkable efficiency in the use of energy for reproduction during the fasting period.
اظهر المزيد [+] اقل [-]Generation of congenic mouse strains by introducing the virus-resistant genes, Mx1 and Oas1b, of feral mouse-derived inbred strain MSM/Ms into the common strain C57BL/6J
2009
Moritoh, K.(Hokkaido Univ., Sapporo (Japan)) | Yamauchi, H. | Asano, A. | Yoshii, K. | Kariwa, H. | Takashima, I. | Isoda, N. | Sakoda, Y. | Kida, H. | Sasaki, N. | Agui, T.
Mx1 (Myxovirus resistance protein) and Oas1b (Oligoadenylate synthetase-1), induced by type 1 interferon (IFN), play a role in early antiviral innate immunity by inhibiting the replication of viruses. In mice, Mx1 and Oas1b confer resistance to the infection of orthomyxoviruses including influenza viruses and flaviviruses including West Nile viruses, respectively. Laboratory mice have been used to study the mechanisms of the pathogenesis of these virus infections; however, it is possible that they are not a suitable model system to study these viruses, since most of the inbred laboratory mouse strains lack both genes. It has been reported that feral mouse-derived inbred strains show resistance to the infection of these viruses due to the presence of intact both genes. In this study, we generated congenic strains in which the Mx or Oas locus of the MSM/Mx (MSM) mouse was introduced to the most widely used mouse strain, C57BL/6J (B6). B6.MSM-Ms mice showed resistance to the infection of influenza virus but not of West Nile virus. On the other hand, B6.MSM-Oas mice showed resistance to the infection of West Nile virus but not of influenza virus. Our results indicate that Mx1 and Oas1b show highly antiviral specificity in mice possessing the same genetic background. Therefore, these congenic mice are useful for not only infection study but also investigation of host defense mechanism to these viruses.
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