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Phospholipase C-mediated vasorelaxing action of melatonin in rat isolated aorta
2005
Kim, S.J. (Chonbuk National University, Jeonju, Republic of Korea) | Baek, S.S. (Chonbuk National University, Jeonju, Republic of Korea) | Kang, H.S. (Chonbuk National University, Jeonju, Republic of Korea) | Kim, J.S. (Chonbuk National University, Jeonju, Republic of Korea), E-mail: kimjs@chonbuk.ac.kr
Melatonin, the principal hormone of the vertebral pineal gland, participates in the regulation of cardiovascular system in vitro and in vivo. However, the effects of melatonin on vascular tissues are still vague. The aim of this study was to assess the relationship between phospholipase C (PLC) and nitric oxide synthase (NOS)/cyclic guanosine 3',5'-monophosphate (cGMP) signaling cascade in the relaxatory action of melatonin in isolated rat aorta. Melatonin induced a concentration-dependent relaxation in phenylephrine (PE)- and KCl-precontraceted endothelium intact (+E) aortic rings.
Show more [+] Less [-]Effect of lithium on endothelial-dependent relaxation to melatonin in rat aorta
2005
Kim, S.J. (Chonbuk National University, Jeonju, Republic of Korea) | Yu, Xian Feng (Chonbuk National University, Jeonju, Republic of Korea) | Cho, I.G. (Chonbuk National University, Jeonju, Republic of Korea) | Kang, H.S. (Chonbuk National University, Jeonju, Republic of Korea) | Kim, J.S. (Chonbuk National University, Jeonju, Republic of Korea), E-mail: kimjs@chonbuk.ac.kr
Melatonin, the principal hormone of the vertebral pineal gland, participates in the regulation of cardiovascular system in vitro and in vivo. Lithium inhibits both inositol polyphosphate phosphatase (IPPase) and inositol monophosphatase (IMPase), which are involved in a wide range of signal transduction pathways. The aim of the present study was to assess the effect of lithium on endothelial-dependent relaxation to melatonin and on the melatonin-induced inhibition of contraction by phenylephrine (PE) in isolated rat aorta. Melatonin induced a concentration-dependent relaxation in PE-precontracted in endothelium-intact (+E) aortic rings.
Show more [+] Less [-]Effect of intensity of fecal pat sampling on estimates of Escherichia coli O157 prevalence
2005
Echeverry, A. | Loneragan, G.H. | Wagner, B.A. | Brashears, M.M.
To evaluate site-to-site variation within fecal pats from cattle with regard to detection of Escherichia coli O157 and determine the effect on the accuracy of prevalence estimates of assay of multiple samples collected from the same fecal pat. 120 freshly voided fecal pats collected from 2 beef feedlots. Procedures-5 samples were systematically collected from each fecal pat and analyzed for E coli O157 via selective preenrichment techniques, immunomagnetic separation, and biochemical tests. Presumptive isolates were definitively identified via agglutination assays and polymerase chain reaction techniques. Best estimators of prevalence were calculated from the distribution of E coli O157-positive samples per pat. Of the 120 fecal pats, 96, 13, 4, 2, 3, and 2 fecal pats had 0, 1, 2, 3, 4, and 5 E coli O157-positive samples, respectively. The greatest estimate of E coli O157 prevalence (20%) was achieved when all 5 samples were assessed; this estimate represented a 2.4- fold increase in prevalence, compared with that provided via analysis of 1 sample/pat (8.2%). Compared with assessment of 5 sites/pat, the relative sensitivity of detecting an E coli O157-positive fecal pat via analysis of 1 site/pat was 40.1%. Results suggest that estimates of E coli O157 prevalence derived from sampling of 1 location/pat are likely underestimates of the true prevalence of this pathogen in fecal pats (and by extension, cattle). Additional research is warranted to confirm these results in situations of high and low prevalence and across different feedlots.
Show more [+] Less [-]Life expectancy in a follow-up study of a birth cohort of boxer dogs from post weaning to 10-years of age
2005
Hagen, van, M.A.E. | Ducro, B.J. | Knol, B.W.
Objective-To determine mortality rate over time, risk factors for death, and heritability of life expectancy in Boxers. Animals-1,733 purebred Boxers born in The Netherlands between January 1994 and March 1995. Procedure-Dogs were followed up from weaning (ie, 49 days of age) to 10 years of age through use of a written questionnaire sent to owners every 6 months. Mortality rate over time, risk factors potentially associated with death, and heritability of life expectancy were examined by use of a proportional hazards model based on the Weibull distribution. Results Estimated mortality rate during the 10-year study period for this birth cohort of Boxers was 45%. The probability of surviving to 5 years of age was 88%; the probability of surviving to 10 years of age was 55%. Estimated effective heritability of life expectancy was 0.076, meaning that in this population, an estimated 76% of the observed variation in life expectancy could be attributed to genetic differences among dogs that were passed from parents to their offspring. Conclusions and Clinical Relevance-Results suggest that cumulative incidence of death from weaning to 10 years of age among this birth cohort of Boxers was 45%. The estimated heritability of life expectancy suggested that life expectancy can be improved by use of selective breeding.
Show more [+] Less [-]Effect of a trivalent vaccine against Staphylococcus aureus mastitis lymphocyte subpopulations, antibody production, and neutrophil phagocytosis
2005
Lee, J.W. | O'Brien, C.N. | Guidry, A.J. | Paape, M.J. | Shafer-Weaver, K.A. | Zhao, X.
The effect of a novel bovine mastitis trivalent vaccine, containing Staphylococcus aureus capsular polysaccharide type 5 (T5), 8 (T8), and 336 (T336), on lymphocyte subpopulations, antibody production, and neutrophil phagocytosis was evaluated. Twenty pregnant heifers were immunized with either the trivalent alone, trivalent emulsified in Freund's incomplete adjuvant (FICA), trivalent in aluminum hydroxide, or adjuvant only (FICA). Immunization was done 30 d before the expected calving date followed by 2 boosts in a 2-week interval. Compared to FICA, serum antigen-specific immunoglobulin (Ig)G1 and IgG2 were significantly increased in all the vaccinated groups before parturition and sustained until 3 wk postpartum. In comparison with the trivalent alone, formulation with either adjuvant enhanced production of IgG2, but not IgG1. Immune sera, which contained the highest amount of antibodies, slightly increased neutrophil phagocytosis to the 3 serotypes of killed S. aureus, but most of the differences were not significant due to large variation between the cows. The percentage of CD4+ lymphocyte was significantly higher in vaccinated groups than that of FICA 4 wk after the primary immunization. In comparison with FICA, cows inoculated with trivalent vaccine and adjuvants had an increased percentage of CD8+ lymphocytes at 2 time points, 2 wk before and after calving. Our results indicated that the whole cell trivalent vaccine, with or without adjuvants, is able to elicit antibody responses specific to the 3 capsular polysaccharide antigens. The increase of T8-specific IgG2 was more noticeable when the vaccine was emulsified with adjuvants.
Show more [+] Less [-]Viral and bacterial diseases in livestock in Mongolia
2005
Odontsetseg, N. (Hokkaido Univ., Sapporo (Japan)) | Mweene, A.S. | Kida, H.
5371 This review focuses on the status of infectious diseases that are serious for animal health and have adverse economic effects in Mongolia. Data presented here are limited due to the lack of published or other easily available documents. Foot-and-mouth disease continues to cause substantial economic losses as exemplified by the outbreak of infection with serotype O PanAsia lineage virus. In the case of the 2001 outbreak, a 65%reduction in export revenues was recorded. In order to ascertain the free status of Mongolia from rinderpest, sero-epidemiological surveillance has been carried out since 2001. In 2004, Mongolia was certified free from rinderpest by Office Interna-tional des Epizooties (OIE). A sharp rise in both animal and human brucello-sis incidence has become a serious problem. Rabies and anthrax remain endemic with occasional human cases. Other prevailing infectious diseases are contagious pustular dermatitis, contagious agalactia, enterotoxemia and ¡pas-teurellosis. The current programs for the control of infectious diseases in livestock in Mongolia lack a definite policy that would enable rapid implementation. A large-scale surveillance of infectious diseases in animals and management of appropriate preventive measures are urgently required in Mongolia.
Show more [+] Less [-]Cloning and characterization of cDNA encoding a prohibitin-like protein from Theileria orientalis
2005
He, W.(Hokkaido Univ., Sapporo (Japan)) | Ohashi, K. | Sugimoto, C. | Tsuji, M. | Onuma, M.
A cDNA clone encoding a prohibitin-like protein (Toprh) was isolated from a piroplasm cDNA library of Theileria orientalis and its nucleotide sequence was determined. An open reading frame, encoding a polypeptide of 278 amino acid residues, was found in Toprh cDNA sequence. An intron of 89 bp was identified when this cDNA clone was compared with the Toprh gene in the genome of T. orientalis. The deduced amino acid sequence of Toprh shares 93.8, 93.1 and 69.1% identities with the prohibitins of T. parva (from chromosome 1), T. annulata (from chromosome 1), and Plasmodium falciparum, (from chromosome 10), respectively. By Western blot analysis, Toprh was found to be expressed in the piroplasm stage of the parasites.
Show more [+] Less [-]Examination of the Lunatic fringe and Uncx4.1 expression by whole-mount in situ hybridization in the embryo of the CKH-Jsr (jumbled spine and ribs) mouse
2005
Okano, S. (Hokkaido Univ., Sapporo (Japan)) | Asano, A. | Sasaki, N. | Kon, Y. | Watanabe, T. | Agui, T.
The CKH-Jsr (jumbled spine and ribs) mouse was found as a spontaneous mutant with malformation of vertebrae, that is, a short trunk and kinky tail. We examined Lunatic Fringe (Lfng and Uncx4. 1 expression in the presomitic mesoderm (PSM) and somites of Jsr-mutant (CKH-Jsr/+) embryos to elucidate pathogenesis of the Jsr mutation. Expression pattern of Lfng in the PSM of Jsr-mutant embryos was similar to that of the normal (C57BL/6) embryos. However, expression pattern of Uncx4. 1 in the somites of Jsr-mutant embryos was impaired to be irregular and mosaic, suggesting that the anterior-posterior (A-P) polarity is disordered in the Jsr mutant. These results indicate that the Jsr mutation disrupts the A-P polarity of somites during the somitogenesis without altering Lfng expression pattern in the PSM.
Show more [+] Less [-]Lycopene and beta-carotene ameliorate catechol estrogen-mediated DNA damage
2005
Muzandu, K. (Hokkaido Univ., Sapporo (Japan)) | Bohi, K.E. | Shaban, Z. | Ishizuka, M. | Kazusaka, A. | Fujita, S.
The consumption of fruits and vegetables is associated with a reduced risk of various ailments, including cancer and cardiovascular diseases. Carotenoids, such as lycopene and beta-carotene, are natural constituents of edible plants and may protect against disease. In this study, the influence of lycopene and beta-carotene on DNA damage caused by catechol-estrogens in vitro is examined. One possible mechanism by which catechol estrogens such as 4- hydroxyestradiol (4-OHE2) and 2- hydroxyestradiol, which cause DNA damage in naked plasmid DNA as well as in cells, contributing to the process of carcinogenesis, is through the generation of reactive oxygen species. It was found that both carotenoids at concentrations ranging from 0.25 to 10 MicroM significantly inhibit strand breakage induced by 4- OHE2/copper sulphate by up to 90%in plasmid DNA with beta-carotene being slightly more effective. No pro-oxidant or cytotoxic effects were observed at the concentrations tested. These carotenoids had a similar, though reduced effect on DNA damage as measured by the comet assay, in Chinese hamster lung fibroblasts. The results obtained show that both lycopene and beta-carotene, most probably and mainly through their potent antioxidant properties, are able to inhibit catecholestrogen-mediated DNA damage.
Show more [+] Less [-]Upregulation of renal renin-angiotensin system in mouse diabetic nephropathy
2005
Tamura, J.(Hokkaido Univ., Sapporo (Japan)) | Konno, A. | Hashimoto, Y. | Kon, Y.
The aim of this study was to clarify the role of the renal renin-angiotensin system (RAS) in diabetic nephropathy (DN) , which was induced by injection of streptozotocin (STZ). Male CBA/N and CBA/J mice were compared in this study. The former possesses a single renin gene, Ren1. whereas the latter carries two renin genes, Ren1 and Ren2. To examine the molecular dynamics of renal RAS, including renin, angiotensinogen (Agt), angiotensin-converting enzyme (Ace), angiotensin type 1 (Agtr1) and type 2 (Agtr2) receptors in experimental DN, we performed laser-microdissection (LMD) followed by reverse transcriptase nested polymerase chain reaction using each specific primer pairs and immunohistochemistry for renin and angiotensin 2. CBA/N mice had a higher response after injection of STZ than CBA/J mice, showing a significant increase of the kidney/body weight ratio, although there was no significant difference between the two strains for the blood glucose level or pancreatic beta-cell response. The onset of renal pathological changes associated with DN was earlier and more severe in CBA/N mice than in CBA/J mice. Distinct immunoreactivities for renin and angiotensin 2 were newly distributed on the flattered epithelial cells in the dilated distal tubules in the cortex as well as the collecting ducts in the cortex and medulla, and were demonstrated more intensity in CBA/N mice than in CBA/J mice. Micro dissectional analysis in both models revealed a higher incidence of RAS-related gene expression in CBA/J, Ren 2 mice than in CBA-N, Ren 1 mice.
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